COMPONENT FOR A PROSTHETIC JOINT

专利摘要:
use of tic cemented by nb and ti in prosthetic joints. an improved composition of sintered titanium carbide is provided. the composition provides an improved degree of strength and toughness and enhanced compatibility with medical imaging. the composition provides good compatibility with polycrystalline diamond, achieving a good mechanical fit in terms of combined compressibility and thermal expansion during the sintering process to minimize the stress or cracking between the substrate and the diamond layer.
公开号:BR112012026799B1
申请号:R112012026799-0
申请日:2011-04-07
公开日:2021-04-13
发明作者:Bill J. Pope；Richard H. Dixon；Jeffery K. Taylor；Troy Medford；Dean C. Blackburn；Victorian Carvajal；David P. Harding；Clayton F. Gardinier
申请人:Dimicron, Inc；
IPC主号:

专利说明:

Background
[0001] The present disclosure relates to methods, materials and apparatus for making super hard components (i.e., polycrystalline cubic boron nitride and polycrystalline diamond) and other hard components. Summary of the invention
[0002] Various methods, materials and devices for making super hard components and other hard components are revealed. Brief description of the drawings
[0003] Figure 1A represents a quantity of diamond input adjacent to a metal alloy substrate before sintering the diamond input and the substrate to create a PDC.
[0004] Figure 1B represents a sintered PDC in which the diamond table, the substrate and the transition zone between the diamond table and the substrate are shown.
[0005] Figure 1BB represents a sintered PDC in which there is a continuous gradient transition from substrate metal through the diamond table.
[0006] Figure 1C represents a substrate before using a CVD or PVD process to form a diamond volume on the substrate.
[0007] Figure 1D represents a compact diamond formed by a CVD or PVD process.
[0008] Figure 1E represents a device, which can be used to load diamond input before sintering.
[0009] Figure 1F represents an oven cycle for removing a binder material from the diamond input before sintering.
[00010] Figures 1G and 1GA represent a pre-compaction assembly, which can be used to reduce free space in diamond input before sintering.
[00011] Figure 2 represents the anvils of a cubic press that can be used to provide a sintering environment of high pressure and high temperature, or for edge formation.
[00012] Figures 3A-1 through 3A-11 represent control of large volumes of powder inputs, such as diamond.
[00013] Figures 4A-4I1 represent some example super hard constructions.
[00014] Figures 5-12 represent the preparation of super hard materials for use in the manufacture of a spinal implant component with a diamond joint surface.
[00015] Figures 13A-13G represent some configurations of super hard material and substrate.
[00016] Figures 14-36 represent preparation of super hard material before sintering and removal after sintering.
[00017] Figures 37a-37c represent sintering of arcuate super hard surfaces.
[00018] Figures 38-50 represent machining and finishing of super hard joint diamond spinal implant components. Detailed Description
[00019] Reference will now be made to the drawings in which the various elements of the modalities will be discussed. People versed in the design of prosthetic joints and other supporting surfaces will understand the application of the various modalities and their principles for sintering and edge formation of super hard and hard components, including those used in prosthetic joints of all types, and components of prosthetic joints , wherever hard, durable or biocompatible products are desired, and for devices other than those exemplified here.
[00020] Various modalities of the manufacturing systems, devices, processes and materials disclosed here refer to components and super-hard and hard surfaces. More specifically, some refer to diamond and sintered polycrystalline diamond (PCD) surfaces. Some modalities make or use a polycrystalline diamond compact (PDC) to provide a biocompatible surface or part for long use, low friction and very strong. Any surface or device that experiences wear and requires strength and durability will benefit from the advances made here.
[00021] The table below provides a comparison of sintered PDC with some other materials. TABLE 1 - COMPARISON OF SINTERIZED PCD WITH OTHER MATERIALS


[00022] In view of the superior hardness of sintered PCD, it is expected that sintered PCD will provide improved durability and wear characteristics.
[00023] In a PDC, the diamond table is chemically bonded and mechanically attached to the substrate in a manufacturing process that typically uses a combination of high pressure and high temperature to form the sintered PCD (see below). The chemical bonds between the diamond table and the substrate are established during the sintering process by combinations of unsatisfied sp3 carbon bonds with unsatisfied substrate metal bonds. Mechanical fixing is a result of the shape of the substrate and diamond table and differences in the physical properties of the substrate and diamond table as well as the gradient interface between the substrate and the diamond table. The resulting sintered PDC forms durable modular support joints and inserts.
[00024] The diamond table can be polished to a glass-like finish and very smooth to obtain a very low coefficient of friction. The high surface energy of sintered PDC makes it work very well as a hinge and load bearing surface when a lubricating fluid is present. Its inherent nature allows it to perform very well when a lubricant is absent as well.
[00025] Although there is discussion here regarding PDCs, the following materials could be considered to form prosthetic joint components: polycrystalline diamond, monocrystal diamond, natural diamond, diamond created by physical vapor deposit, diamond created by chemical vapor deposit, diamond-like carbon, carbonate, cubic boron nitride, hexagonal boron nitride, or a combination thereof, cobalt, chromium, titanium, vanadium, stainless steel, niobium, aluminum, nickel, hafnium, silicon, tungsten, molybdenum, aluminum, zirconium , nitinol, cobalt chromium, cobalt chromium molybdenum, cobalt chromium tungsten, tungsten carbide, titanium carbide, tantalum carbide, zirconium carbide, hafnium carbide, Ti6 / 4, silicon carbide, chromium carbide, vanadium carbide, yttrium stabilized zirconia, magnesium stabilized zirconia, zirconia-hardened alumina, hafnium titanium molybdenum, alloys including one or more of the above metals, ceramics, quartz, gr sapphire, sapphire, combinations of these materials, combinations of these and other materials, and other materials can also be used for a desired surface. Sintered polycrystalline diamond compacts
[00026] A useful material for making joint support surfaces is a sintered polycrystalline diamond compact. Diamond has the highest hardness and the lowest coefficient of friction of any material currently known. Synthesized PDCs are chemically inert, impermeable to all solvents, and have the highest thermal conductivity at room temperature of any known material.
[00027] In some embodiments, a PDC provides exclusive chemical bonding and mechanical gripping between the diamond and the substrate material. A PDC, which uses a substrate material, will have a chemical bond between the substrate material and the diamond crystals. The result of this structure is an extremely strong link between the substrate and the diamond table.
[00028] A method by which PDC can be manufactured is described later in this document. In summary, it involves sintering diamond crystals with each other, and with a substrate under high pressure and high temperature. Figures 1A and 1B illustrate the physical and chemical processes involved in the manufacture of PDCs.
[00029] In figure 1A, a quantity of diamond input 130 (such as diamond powder or crystals) is placed adjacent to a substrate containing metal 110 before sintering. In the region of the diamond input 130, individual diamond crystals 131 can be seen, and between the individual diamond crystals 131 there are interstitial spaces 132. If desired, an amount of catalyst-solvent metal can be placed in the interstitial spaces 132. The substrate may also contain catalyst-solvent metal.
[00030] Substrate 110 may be an appropriate pure metal or alloy, or a cemented carbide containing an appropriate alloy or metal as a cementing agent such as cobalt-cemented tungsten carbide or other materials mentioned herein. Substrate 110 may be a metal with high tensile strength. On a chromium-cobalt substrate, the chromium-cobalt alloy will serve as a catalyst-solvent metal to solvate diamond crystals during the sintering process.
[00031] The illustration shows the individual diamond crystals and the contiguous metal crystals on the metal substrate. The interface 120 between diamond powder and substrate material is a region where the connection of the diamond table to the substrate must occur. In some embodiments, a boundary layer of a third material other than diamond and the substrate is placed at interface 120. This boundary layer material, when present, can serve a variety of functions including, but not limited to, increasing the connection of the diamond table with the substrate, and reduction of the residual stress field at the diamond substrate interface.
[00032] After diamond powder or crystals and substrate are assembled as shown in figure 1A, the assembly is subjected to high pressure and elevated temperature as described later here to cause diamond crystals to bond with diamond crystals and the substrate. The resulting structure of a sintered polycrystalline diamond table attached to a substrate is called a polycrystalline diamond compact or a PDC. A compact, as the term is used here, is a composite structure of two different materials, such as diamond crystals, and a metal substrate. The analogous structure incorporating cubic boron nitride crystals in the sintering process instead of diamond crystals is called polycrystalline cubic boron nitride (PCBNC) compact. Many of the processes described here for the manufacture and finishing of PDC structures and parts work in a similar way to PCBNC. In some embodiments, PCBNC can be replaced by PDC. It should be noted that a PDC can also be made of independent diamond without a separate substrate, as described elsewhere here.
[00033] Figure 1B represents a PDC 101 after sintering high pressure and high temperature of diamond input on a substrate. In the PDC structure, there is an identifiable volume of substrate 102, an identifiable volume of diamond table 103, and a transition zone 104 between diamond table and substrate containing diamond crystals and substrate material. Crystalline grains of substrate material 105 and synthesized diamond crystals 106 are shown.
[00034] On a casual examination, the finished compact of figure 1B will appear to consist of a solid diamond table 103 attached to substrate 102 with a discrete boundary. On close examination, however, a transition zone 104 between diamond table 103 and substrate 102 can be characterized. This zone represents a gradient interface between the diamond table and the substrate with a gradual transition of ratios between diamond content and metal content. On the substrate side of the transition zone, there will be only a small percentage of diamond crystals and a high percentage of substrate metal, and on the diamond table side, there will be a high percentage of diamond crystals and a low percentage of metal. substrate. Due to this gradual transition from polycrystalline diamond to substrate metal ratios in the transition zone, the diamond table and the substrate have a gradient interface.
[00035] In the transition zone or gradient transition zone where diamond crystals and substrate metal are intermixed, chemical bonds are formed between the diamond and metal. From the transition zone 104 to the diamond table 103, the metal content decreases and is limited to catalyst-solvent metal that fills the three-dimensional vein-like structure with interstitial void space, openings or roughness 107 in the table structure. sintered diamond 103. The catalyst-solvent metal found in the voids or openings 107 may have been wiped off the substrate during sintering or the catalyst-solvent metal may have been added to the diamond input prior to sintering.
[00036] During the sintering process, there are three types of chemical bonds that are created: diamond-to-diamond bonds, diamond-to-metal bonds, and metal-to-metal bonds. In the diamond table, there are diamond-to-diamond bonds (spa carbon bonds) created when diamond particles partially solvate in the catalyst-solvent metal and are then bonded together. On the substrate and on the diamond table, there are metal-to-metal bonds created by the high pressure and high temperature sintering process. And in the gradient transition zone, diamond-to-metal bonds are created between diamond and catalyst-solvent metal.
[00037] The combination of these various chemical bonds and the mechanical grip exerted by catalyst-solvent metal on the diamond table as well as on the interstitial spaces of the diamond table diamond structure provide extraordinarily high bond strength between the diamond table and the substrate. Interstitial spaces are present in the diamond structure and those spaces are typically filled with catalyst-solvent metal, forming veins of catalyst-solvent metal in the polycrystalline diamond structure. this bonding structure contributes to the compact's extraordinary fracture toughness, and the metal veins in the diamond table act as energy dissipators by stopping the propagation of incipient cracks in the diamond structure. The transition zone and metal vein structure provide the compact with a gradient of material properties between those of the diamond table and those of substrate material, further contributing to the extreme toughness of the compact. The transition zone can also be called an interface, a gradient transition zone, a composition gradient zone, or a composition gradient, depending on its characteristics. The transition zone distributes substrate / diamond stress over the thickness of the zone, reducing the high temperature stress of a distinct linear interface. The residual stress in question is created as the pressure and temperature are reduced at the conclusion of the high pressure / high temperature sintering process due to the difference in pressure and thermal expansive properties of the substrate and diamond materials.
[00038] The diamond sintering process takes place under conditions of extremely high pressure and high temperature. According to the inventors' best theoretical and experimental understanding, the diamond sintering process progresses through the following sequence of events: under pressure, a cell containing unbound diamond powder input or crystals (diamond input) and a substrate is heated to a temperature above the melting point of the substrate metal 110 and molten metal flowing or sweeping into the interstitial voids 107 between the adjacent diamond crystals 106. It is carried by the pressure gradient to fill the voids as well as being pulled inward by the surface energy or capillary action of the large surface area of the diamond crystals 106. As the temperature continues to rise, carbon atoms on the surface of the diamond crystals dissolve in this interstitial molten metal, forming a carbon solution.
[00039] At the appropriate temperature and pressure limit, diamond becomes the thermodynamically favored crystalline carbon allotrope. As the solution becomes supersaturated with respect to C.sub.d (carbon diamond), carbon in that solution begins to crystallize like a diamond on the surfaces of diamond crystals by connecting adjacent diamond crystals together with diamond-diamond bonds in a sintered polycrystalline diamond structure 106. The interstitial metal fills the remaining void space that forms the vein-like lattice structure 107 in the diamond table by capillary forces from pressure driving forces. Due to the crucial role that interstitial metal plays in forming a solution of carbon atoms and stabilizing these reactive atoms during the diamond crystallization phase in which the polycrystalline diamond structure 106 is formed, the metal is referred to as a catalyst-solvent metal .
[00040] Figure 1BB represents a polycrystalline diamond compact having both substrate metal 180 and diamond 181, but in which there is a continuous gradient transition 182 from substrate metal to diamond. In such a compact, the gradient transition zone can be the entire compact, or a portion of the compact. The substrate side of the compact can contain almost pure metal for easy machining and attachment to other components, while the diamond side can be extremely hard, smooth and hard for use in a hostile work environment.
[00041] In some embodiments, an amount of catalyst-solvent metal can be combined with the diamond input prior to sintering. This is found to be necessary when forming thick PCD tables, solid PDC structures, or when using multimodal fine diamonds where there is little residual free space in the diamond powder. In each of these cases, there may not be enough ingress of catalyst-solvent metal through the scanning mechanism to properly mediate the sintering process as a solvent-catalyst. The metal can be added by directly adding powder, or by generating metal powder on the spot with an attrition laminator or by the well-known method of chemical reduction of metal salts deposited in diamond crystals. Added metal can constitute any amount less than 1% by weight, the greater than 35%. This additional metal can consist of the same metal or alloy as found in the substrate, or it can be a different metal or alloy selected due to its mechanical and material properties. Example ratios of diamond inputs to catalyst-solvent metal prior to sintering include mass ratios of 70:30, 85:15, 90:10 and 95:15. The metal in the diamond input can be additional powder metal, metal added by an attractor method, vapor deposition or chemical reduction of powdered metal.
[00042] When sintering diamond on a substrate with an interface boundary layer, it may be that no catalyst-solvent metal from the substrate is available to sweep into the diamond table and participate in the sintering process. In this case, the boundary layer material, if composed of an appropriate material, metal or alloy that can function as a catalyst-solvent, can serve as a scanning material mediating the diamond sintering process. In other cases where the desired boundary material cannot serve as a catalyst-solvent, an appropriate amount of catalyst-solvent metal powder as described here is added to the diamond crystal input as described above. This assembly is then carried out through the sintering process. In the absence of a substrate metal source, the catalyst-solvent metal for the diamond sintering process must be supplied entirely from the added metal powder. The boundary material can chemically bond to the substrate material, and can chemically bond to the diamond table and / or the catalyst-solvent metal added to the diamond table. The rest of the sintering and fabrication process can be the same as with the conventional catalyst-solvent sweep and fabrication process.
[00043] For the sake of simplicity and clarity in this patent, the substrate, transition zone, and diamond table were discussed as separate layers. However, it is important to realize that the finished sintered object can be a composite structure characterized by a transition from a continuous gradient of substrate material to a diamond table instead of as distinct layers with clear and discrete boundaries, hence the term “compact”.
[00044] In addition to the sintering processes described above, diamond parts suitable for use as modular support inserts and joint components can also be manufactured as independent polycrystalline diamond structures or solid without a substrate. These can be formed by placing the diamond powder combined with an appropriate amount of catalyst-solvent metal powder added as described above in a refractory metal can (typically Ta, Nb, Zr or Mo) with a shape that approximates the shape of the desired final part. This assembly is then carried out through the sintering process. However, in the absence of a substrate metal source, the catalyst-solvent metal for the diamond sintering process must be supplied entirely from the added metal powder. With appropriate finishing, objects thus formed can be used as they are, or bonded to metal or other substrates.
[00045] Sintering is a method of creating a diamond table with a strong and durable constitution. Other methods of producing a diamond table that may or may not be bonded to a substrate are possible. Currently, these are typically not as strong or durable as those manufactured using the sintering process. It is also possible to use these methods to form diamond structures directly on substrates suitable for use as joints and modular support inserts. A polycrystalline diamond table with or without a substrate can be manufactured and later fixed to inserts and modular support joints in a place such that it will form a surface. Fixation can be performed with any appropriate method, including welding, brazing, sintering, diffusion welding, diffusion bonding, inertial welding, adhesive bonding, or use of fasteners such as screws, bolts, or rivets. In the case of fixing a diamond table without a substrate with another object, the use of such methods as brazing, diffusion / bonding or inertial welding may be more appropriate.
[00046] Although sintering at high temperature / high pressure is a method for creating a diamond surface, other methods for producing a volume of diamond can also be employed. For example, chemical vapor deposition (CVD), or physical vapor deposition (PVD) processes can be used. CVD produces a diamond layer by thermally cracking an organic molecule and depositing carbon radicals on a substrate. PVD produces a diamond layer by electrically causing carbon radicals to be ejected from a source material and deposit on a substrate where they form a diamond crystal structure.
[00047] The CVD and PVD processes have some advantages over sintering. Sintering is performed on large and expensive presses at high pressure (such as 45-68 kilobars) and at high temperatures (such as 1200 to 1500 degrees Celsius). It is difficult to obtain and maintain desired component shape using a sintering process due to the flow of high pressure media used and possible deformation of substrate materials.
[00048] On the contrary, CVD and PVD occur at atmospheric pressure or lower, so that there is no need for a pressure medium and there is no deformation of substrates.
[00049] Another disadvantage of sintering is that it is difficult to obtain some geometries in a sintered PDC. When CVD or PVD are used, however, the gas phase used for depositing carbon radicals can fully conform to the shape of the object being coated, making it easy to obtain a desired non-flat shape.
[00050] Another potential disadvantage of sintering PDCs is that the finished component will tend to have large residual stresses caused by differences in the coefficient of thermal expansion and modulus between the diamond and the substrate. Although residual stresses can be used to improve part resistance, they can also be disadvantageous, when CVD or PVD is used, residual stresses can be minimized because the PVD and CVD processes do not involve a significant pressure transition (from 68 Kbar to atmospheric pressure in high pressure and high temperature sintering) during manufacture.
[00051] Another potential disadvantage of sintering PDCs is that some substrates have been discovered that are suitable for sintering. Tungsten carbide is a common choice for substrate materials. Non-flat components were made using other substrates. When CVD or PVD are used, however, synthetic diamond can be placed on many substrates, including titanium, most carbides, silicon, molybdenum and others. This is because the temperature and pressure of the CVD and PVD coating processes are low enough that differences in thermal expansion coefficient and modulus between diamond and substrate are not as critical as they are in a high pressure and high temperature sintering process. .
[00052] An additional difficulty in the manufacture of synthesized PDCs is that as the size of the part to be manufactured increases, the size of the press must also increase. Diamond sintering will only occur at certain pressures and temperatures, such as those described here. To manufacture larger sintered polycrystalline diamond compacts, press plunger pressure (tonnage) and size of tools (such as dies and anvils) must be increased to obtain the pressure required for sintering to occur. However, increasing the size and capacity of a press is more difficult than simply increasing the dimensions of its components. There may be practical physical size limitations on the size of the press due to the manufacturing process used to produce press tools.
[00053] Tools for a press are typically made of cemented tungsten carbide. To make tools, the cemented tungsten carbide is sintered in a vacuum oven followed by pressing in a hot isostatic press apparatus (“IIIP”). Edge formation must be carried out in a manner that maintains a uniform temperature throughout the tungsten carbide to obtain uniform physical qualities. These requirements impose a practical limit on the size of tools that can be produced for a press that is useful for sintering PDCs. The limit on the size of tools that can be produced also limits the size of the press that can be produced.
[00054] CVD and PVD manufacturing devices can be increased in size with some limitations, allowing them to produce polycrystalline diamond compacts of almost any desired size.
[00055] CVD and PVD processes are also advantageous because they allow precise control of the thickness and uniformity of the diamond coating to be applied to a substrate. The temperature is adjusted in the range of 500 to 1000 degrees Celsius, and the pressure is adjusted in a range less than 1 atmosphere to obtain the desired thickness of the diamond coating.
[00056] Another advantage of CVD and PVD processes is that they allow the manufacturing process to be monitored as it progresses. A CVD or PVD reactor can be opened before the manufacture of a part is completed so that the thickness and quality of the diamond coating being applied to the part can be determined. From the thickness of the diamond coating that has already been applied, time to completion of fabrication can be calculated. Alternatively, if the coating is not of the desired quality, the manufacturing processes can be aborted to save time and money.
[00057] On the contrary, the sintering of PDCs is carried out as a batch process that cannot be interrupted, and the sintering progress cannot be monitored. The pressing process must be carried out until completion and the part can only be examined later.
[00058] A cubic press (that is, the press has six anvil faces) can be used to transmit high pressure for assembly under sintering or edge formation. For example, a cubic press applies pressure along 3 geometry axes from six different directions. Alternatively, a belt press and a cylindrical cell can be used to obtain similar results. Other presses that can be used include a cylinder-piston press and a tetrahedral press. With reference to figure 2, a representation of the 6 anvils of a 3720 cubic press is provided. The anvils 3721, 3722, 3723, 3724, 3725 and 3726 are located around a pressure assembly 3730 to perform sintering or edge formation by using high temperature and high pressure. The exact conditions of sintering or edge formation depend on the materials used, size of the component being manufactured, and the desired material and strength properties in the finished product.
[00059] A cubic dressing is normally based on six carbide anvils spun on solid hydraulic cylinders converging simultaneously into a high pressure capsule in the shape of a cube. This tri-axial system generates an essentially isostatic high pressure condition, which is particularly suitable for sintering products with complex three-dimensional geometries. Such a press system will be integrated with computerized control systems to ensure optimal and compatible temperature, time and pressure sintering conditions.
[00060] A belt press uses two carbide punches converging on a high pressure capsule contained in a carbide matrix to generate the extreme pressure required to sinter polycrystalline products. Steel belts fitted by shrinkage pre-tension the internal carbide matrix, allowing it to withstand the immediate internal pressure that occurs during sintering.
[00061] A cylinder-piston press is similar to a belt press, with a high pressure capsule contained in the cylindrical bore of a carbide die. Two free-floating carbide pistons engage the bore, pressurizing the capsule when the load is applied by conical carbide anvils. The carbide matrix is supported by radial hydraulic pressure instead of a series of steel belts. This allows simultaneous pressurization of both the inside and the outside of the die. Since this press is essentially a gasket-free system, there is very little movement of material in the pressure volume during pressurization and heating. PVD and CVD diamond
[00062] CVD is performed in a device called a reactor. A basic CVD reactor includes four components. The first component of the reactor is one or more gas inlets. Gas inlets can be chosen based on whether gases are pre-mixed prior to introduction into the chamber or whether the gases are allowed to mix for the first time in the chamber. The second component of the reactor is one or more sources of energy for the generation of thermal energy. A power source is needed to heat the gases in the chamber. A second energy source can be used to heat the substrate material evenly to obtain a uniform diamond coating on the substrate. The third component of the reactor is a stage or platform on which a substrate is placed. The substrate will be coated with diamond during the CVD process. Stages used include a fixed stage, a translation stage, a rotation stage and a vibrating stage. An appropriate stage should be chosen to achieve the desired quality and uniformity of diamond coating. The fourth component of the reactor is an outlet port for removing exhaust gas from the chamber. After the gas has reacted with the substrate, it must be removed from the chamber as quickly as possible so that it does not participate in other reactions, which would be detrimental to the diamond coating.
[00063] CVD reactors are classified according to the energy source used. The energy source is chosen to create the desired species needed to deposit a thin diamond film. Some types of CVD reactor include plasma-assisted microwave, hot filament, electron beam, single, double or multiple laser beam, are DC and jet discharge. These reactors differ in the way in which they transmit thermal energy to the gas species and in their efficiency in dividing gases into the species required for diamond deposits. It is possible to have a set of lasers to perform local heating inside a high pressure cell. alternatively, a set of optical fibers could be used to provide light in the cell.
[00064] The basic process by which CVD reactors work is as follows. A substrate is placed in the reactor chamber. Reagents are introduced into the chamber via one or more gas inlets. For diamond CVD, methane (CH. Sub.4) and hydrogen (H.sub.2) gases can be taken into the chamber in a pre-mixed form. Instead of methane, any carbon-containing gas to which the carbon is sp3 bonded can be used. Other gases can be added to the gas flow to control the quality of the diamond film, deposit temperature, gain structure and growth rate. These include oxygen, carbon dioxide, argon, halogens and others.
[00065] The gas pressure in the chamber is maintained at approximately 100 torn. Flow rates for gases through the chamber are approximately 10 standard cubic centimeters per minute for methane and approximately 100 standard cubic centimeters per minute for hydrogen. The composition of the gas phase in the chamber is in the range of 90-99.5% hydrogen and 0.5-10% methane.
[00066] When gases are introduced into the chamber, they are heated. Heating can be accomplished by many methods. In a plasma-assisted process, the gases are heated by passing them through a plasma. Otherwise, the gases can be passed over a series of wires like those used in a hot filament reactor.
[00067] Heating of methane and hydrogen will divide them into several free radicals. Through a complicated mixture of reactions, carbon is deposited on the substrate and joins with another carbon to form a crystalline diamond by sp3 bonding. The atomic hydrogen in the chamber reacts with and removes hydrogen atoms from methyl radicals attached to the substrate surface to create molecular hydrogen, leaving a clear solid surface for additional free radical deposition.
[00068] If the substrate surface promotes the formation of sp2 carbon bonds, or if the gas composition, flow rates, substrate temperature or other variations are incorrect, then graphite instead of diamond will grow on the substrate.
[00069] There are many similarities between CVD reactors and processes and PVD reactors and processes. PVD reactors differ from CVD reactors in the way they generate the type of deposit and in the physical characteristics of the type of deposit. In a PVD reactor, a source material plate is used as a thermal source, instead of having a separate thermal source as in CVD reactors. A PVD reactor generates electrical polarization through a source material plate to generate and eject carbon radicals from the source material. The reactor bombards the source material with high energy ions. When high energy ions collide with source material, they cause the desired carbon radicals to be ejected from the source material. Carbon radicals are ejected radially from the source material into the chamber. The carbon radicals are then deposited on whatever is in their path, including the stage, the reactor itself and the substrate.
[00070] With reference to figure 1C, a substrate 140 of appropriate material is represented having a deposit face 141 on which diamond can be deposited by a PVD or CVD process. Fig. 1D represents the substrate 140 and the deposit face 141 on which a diamond volume 142 has been deposited by CVD or PVD processes. A small transition zone 143 is present in which both diamond and substrate are located. In comparison to figure 1B, it can be seen that the PVD or CVD diamond deposited on a substrate does not have the most extensive gradient transition zone of sintered polycrystalline diamond compacts because there is no sweeping of catalyst-solvent metal through the table. diamond in a PVD or CVD process.
[00071] Both CVD and PVD processes obtain diamond deposits per line of sight. Means (such as vibration and rotation) are provided to expose all desired surfaces for diamond deposition. If a vibrating stage is to be used, the surface will vibrate up and down with the stage and thereby present all surfaces to the free radical source.
[00072] There are several methods that can be implemented to coat cylindrical objects with diamond using CVD or PVD processes. If a plasma-assisted microwave process is to be used to obtain diamond deposits, then the object to receive the diamond must be directly under the plasma to obtain the highest quality and most uniform diamond coating. A rotation or translation stage can be used to present every aspect of the surface to the plasma for diamond coating. As the stage rotates or translates, all portions of the surface can be placed directly under the coating plasma in order to obtain a sufficiently uniform coating.
[00073] If a hot filament CVD process is used, then the surface must be placed in a stationary stage. Wires or filaments (typically tungsten) are extended over the stage so that their coverage includes the surface to be coated. The distance between the filaments and the surface and the distance between the filaments themselves can be chosen to obtain a uniform diamond coating directly under the filaments.
[00074] Diamond surfaces can be manufactured by CVD and PVD process by coating a substrate with diamond or by creating an independent volume of diamond, which is then assembled for use. A diamond-independent volume can be created by CVD and PVD processes in a two-step operation. First, a thick diamond film is deposited on an appropriate substrate, such as silicon, molybdenum, tungsten or others. Second, the diamond film is released from the substrate.
[00075] As desired, segments of diamond film can be cut, as by using a Q-switched YAG laser. although diamond is transparent to a YAG laser, there is usually a sufficient amount of carbon bound by sp2 (as found in graphite) to allow cutting to occur. If not, then a line must be drawn on the diamond film using carbon-based paint. the line should be sufficient to allow the cut to start, and after starting, the cut will proceed slowly.
[00076] After an appropriately sized piece of diamond has been cut from a diamond film, it can be attached to a desired object to serve as a surface. For example, the diamond can be fixed to a substrate by welding, diffusion bonding, bonding bonding, mechanical bonding or bonding by high temperature and high pressure in a press.
[00077] Although CVD and PVD diamonds on a substrate do not have a gradient transition zone that is found in sintered polycrystalline diamond compacts, the CVD and PVD process can be conducted to incorporate metal into the diamond table. As mentioned elsewhere here, incorporating metal into the diamond table increases the adhesion of the diamond table to its substrate and can reinforce the polycrystalline diamond compact. The incorporation of diamond in the diamond table can be used to obtain a diamond table with a coefficient of thermal expansion and compressibility different from that of pure diamond, and consequently increasing the fracture toughness of the diamond table in comparison with pure diamond. Diamond has a low coefficient of thermal expansion and low compressibility compared to metals. Therefore, the presence of metal with diamond in the diamond table obtains a coefficient more similar to metal and a higher thermal expansion and the average compressibility for the diamond table than for pure diamond. consequently, residual stresses at the diamond table and substrate interface are reduced, and delamination of the diamond table from the substrate is less likely.
[00078] A pure diamond crystal also has low fracture toughness. Therefore, in pure diamond, when a small crack is formed, every diamond component fails catastrophically. In comparison, metals have a high fracture toughness and can accommodate large cracks without catastrophic failure. The incorporation of metal in the diamond table achieves greater fracture toughness than pure diamond. In a diamond table having interstitial spaces and metal in those interstitial spaces, if a crack forms in the diamond and propagates to an interstitial space containing metal, the crack will end at the metal and catastrophic failure will be avoided. Due to this characteristic, a diamond-to-metal table in its interstitial spaces is able to withstand much higher forces and workloads without catastrophic failure compared to pure diamond.
[00079] Diamond-diamond bonding tends to decrease as the metal content in the diamond table increases. CVD and PVD processes can be conducted so that a transition zone is established. However, the surface can be essentially pure PCD for low wear properties.
[00080] Generically PVD and CVD diamonds are formed without large interstitial spaces filled with metal. Consequently, most PVD and CVD diamonds are more fragile or have a lower fracture toughness than synthesized PDCs. CVD and PVD diamonds can also exhibit the maximum residual stresses possible between the diamond table and the substrate. It is possible, however, to form CVD and PVD diamond films that have metal incorporated in them with a uniform or functionally gradient composition.
[00081] One method of incorporating metal into a PVD or CVD diamond film is to use two different source materials to simultaneously deposit the two materials on a substrate in a PVD or CVD diamond production process. This method can be used regardless of whether diamond is being produced by CVD, PVD or a combination of the two.
[00082] Another method for incorporating metal into a CVD diamond film is chemical vapor infiltration. This process would first create a layer of porous material, and then fill the pores by infiltrating chemical vapor. The thickness of the porous layer should be approximately equal to the desired thickness for the gradient or uniform layer. The size and distribution of the pores can be used to control the final composition of the layer. The vapor infiltration deposit occurs primarily at the interface between the porous layer and the substrate. As the deposit continues, the interface along which the material is deposited moves out from the substrate to fill pores in the porous layer. As the growth interface moves outward, the deposit temperature along the interface is maintained by moving the sample in relation to a heater or by moving the heater in relation to the growth interface. It is imperative that the porous region between the outside of the sample and the growth interface is maintained at a temperature that does not promote material deposition (the pore filler material or undesirable reaction products). The deposit in this region would close the pores prematurely and prevent infiltration and deposit of the desired material in internal pores. The result would be a substrate with open porosity and poor physical properties. Laser diamond deposit
[00083] Another alternative manufacturing process that can be used to produce surfaces and components involves the use of energy beams, such as laser energy, to vaporize constituents on a substrate and redeposit those constituents on the substrate in a new form, such as in the form of a diamond coating. As an example, a metal, polymer or other substrate can be obtained or produced containing carbon, carbides or other desirable constituent elements. Appropriate energy, such as laser energy, can be directed to the substrate to cause constituent elements to move from within the substrate to the surface of the substrate adjacent to the area of application of energy to the substrate. The continuous application of energy to the constituent elements concentrated on the substrate surface can be used to cause vaporization of some of those constituent elements. The vaporized constituents can then be reacted with another element to change the properties and structure of the vaporized constituent elements.
[00084] Next, the vaporized and reacted constituent elements (which can be diamond) can be diffused on the substrate surface. A separate fabricated coating can be produced on the surface of the substrate having a chemical composition equal to or different from that of the vaporized and reacted constituent elements. Alternatively, some of the altered constituent elements that have been diffused into the substrate can be vaporized and reacted again and deposited as a coating on the substrate. Through this process and variations thereof, suitable coatings such as diamond, cubic boron nitride, diamond-like carbon, B.sub4C, SiC, TiC, TiB, cCN, Cr.sub.3C.sub2, and Si.sub.3N. sub.4 can be formed on a substrate.
[00085] In other manufacturing environments, high temperature laser application, electroplating, cathodic sublimation, plasma deposition excited by energy laser or other methods can be used to place a diamond volume, diamond-like material, a hard material or a super hard material in a place that will serve as a surface.
[00086] In light of the disclosure here, those of ordinary skill in the art will understand the apparatus, materials and process conditions necessary for the formation and use of high quality diamond on a substrate using any of the manufacturing methods described here to create a surface diamond. Material ownership considerations
[00087] In areas outside joints and modular support inserts, particularly in the field of rock drill cutters, polycrystalline diamond compacts have been used for some time. Historically, these cutters were cylindrical in shape with a flat diamond table at one end. The diamond surface of a cutter is much smaller than the surface required for most modular support inserts and joints. As such, polycrystalline diamond cutter manufacturing methods and geometry are not directly applicable to joints and modular support inserts.
[00088] There is a specific problem posed by the manufacture of a non-flat diamond surface. Non-planar component design requires pressure to be applied radially when making the part. During the high pressure sintering process, described in detail below, all displacements must be along a radian that emanates from the center of the sphere that will be produced to obtain the non-flat geometry. To achieve this in high pressure / high temperature compression, an isostatic pressure field must be created. During the manufacture of such non-flat parts, if there is any component of voltage deviation, it will result in distortion of the part and may render the manufactured part useless.
[00089] Special considerations that must be made when making non-flat polycrystalline diamond compacts are discussed below. Module
[00090] Most polycrystalline diamond compacts include both a diamond table and a substrate. The material properties of the diamond and substrate may be compatible, but the sintering process at high temperature and high pressure in the formation of a polycrystalline diamond compact can result in a component with excessively high residual stresses. For example, for a polycrystalline diamond compact using tungsten carbide as the substrate, the sintered diamond has a Young's modulus of approximately 120 million p.s.i., and tungsten carbide cemented with cobalt has a modulus of approximately 90 million p.s.i. Module refers to the slope of the stress curve plotted against the stress for a material. Module indicates the stiffness of the material Volume module refers to the ratio of isostatic stress to isostatic stress, or the reduction in unit volume of a material versus the pressure or stress applied.
[00091] As diamond and most substrate materials have such a high modulus, a very small displacement or tension of the polycrystalline diamond compact can induce very large stresses. If the stresses exceed the resistance to deformation of the diamond or substrate, the component will fail. The stronger polycrystalline diamond compact is not necessarily tension-free. In a polycrystalline diamond compact with optimal residual stress distribution, more energy is needed to induce a fracture than in a stress-free component. Thus, the difference in modulus between the substrate and the diamond must be observed and used to design a component that will have the best strength for its application with sufficient abrasion resistance and fracture toughness. Thermal expansion coefficient (“CTE”)
[00092] The extent to which diamond and its substrate differs in how they deform in relation to changes in temperature also affects their mechanical compatibility. The thermal expansion coefficient (“CTE”) is a measure of the unit change of a dimension with unit change in temperature or the propensity of a material to expand under heat or to contract when cooled. As a material experiences a phase change, calculations based on CTE in the initial phase will not be applicable. It is observable that when compacts of materials with different CTEs and modules are used, they will tension differently at the same tension.
[00093] PCD has a CTE in the wheel of (0.0508 - 0.1016 mm per mm) 2 - 4 micro inches per inch (10.sup ..- 6 inches) of material per degree (.mm.pol. / pol.grau.C). on the contrary, carbide has a CTE of the order of 6-8 mu.pol./pol.grau. although these values appear to be numerically close, the influence of the high modulus creates very high residual stress fields when a temperature gradient of hundreds of degrees are imposed on the combination of substrate and diamond. The difference in thermal expansion coefficient is less of an issue in simple flat PDCs than in the manufacture of complex or non-flat shapes. When a non-flat PDC is manufactured, differences in the CTE between the diamond and the substrate can cause high residual stress with subsequent cracking and failure of the diamond table, the substrate or both at any time during or after sintering at elevated temperature / high pressure . Expansion and deviatoric stresses
[00094] The substrate and diamond assembly will experience a reduction in free volume during the sintering process. The sintering process, described in detail below, involves subjecting the diamond and substrate assembly to pressure commonly in the range of approximately 40 to approximately 68 kilobar. The pressure will cause a reduction in volume of the substrate. Some geometric distortion of the diamond and / or substrate may also occur. The stress that causes geometric distortion is called the deviatoric stress, and the stress that causes change in volume is called the dilation stress. In an isostatic system, the deviatoric stresses add up to zero and only the dilatoric tension component remains. Failure to consider all of these stress factors when designing and sintering a complex geometry polycrystalline diamond component (such as concave and convex non-planar polycrystalline diamond compacts) will likely result in process failure. Diamond input free volume reduction
[00095] As a consequence of the physical nature of the input diamond, large amounts of free volume are present unless special preparation of the input is undertaken prior to sintering. It is necessary to eliminate as much of the free volume in the diamond as possible, and if the free volume present in the diamond input is too large, then sintering may not occur. It is also possible to eliminate the free volume during sintering if a press with sufficient piston displacement is used. It is important to maintain a desired uniform geometry of the diamond and substrate during any process that reduces free volume in the input, or a defective or distorted component may result. Selection of catalyst-solvent metal
[00096] The formation of synthetic diamond in a high temperature and high pressure press without the use of catalyst-solvent metal is not a viable method at this time, although it may become viable in the future. A catalyst-solvent metal is required to obtain the desired synthetic diamond crystal formation. The catalyst-solvent metal primarily solvates carbon preferably from the sharp contact points of the diamond input crystals. It then recrystallizes the carbon as a diamond in the interstices of the diamond matrix with sufficient diamond-diamond bonding to obtain a solid with 95 to 97% theoretical density with solvent metal 5-3% by volume. That solid distributed over the substrate surface is referred to here as a polycrystalline diamond table. The catalyst-solvent metal also increases the formation of chemical bonds with substrate atoms.
[00097] One method for adding the catalyst-solvent metal to the diamond input is to cause it to sweep from the substrate containing the catalyst-solvent metal during high temperature and high pressure sintering. Powdered catalyst-solvent metal can also be added to the diamond input prior to sintering, particularly if thicker diamond tables are desired. An attractor method can also be used to add the catalyst-solvent metal to the diamond input prior to sintering. If too much or too little catalyst-solvent metal is used, then the resulting part may not have the desired mechanical properties, so it is important to select an amount of catalyst-solvent metal and a method of adding it to the forward input that it is suitable for the specific part to be manufactured. Diamond input particle size and distribution
[00098] The durability of the finished diamond product is integrally linked to the size of the input diamond and also to the particle distribution. The selection of the appropriate size (s) of diamond input and particle distribution depends on the service requirement of the specimen and also its working environment. The durability of polycrystalline diamond is increased if smaller diamond input crystals are used and a highly bonded diamond-diamond table is obtained.
[00099] Although polycrystalline diamond can be made from a single modal diamond input, the use of multimodal input increases both impact resistance and wear resistance. The use of a combination of large crystal sizes and small crystal sizes of diamond input together provides a part with high impact resistance and wear resistance, in part because the interstitial spaces between the large diamond crystals can be filled with crystals small diamond rings. During sintering, the small crystals will solvate and reprecipitate in a way that links all diamond crystals into a tightly bonded and strong compact. Diamond input loading methodology
[000100] Contamination of the diamond input before or during loading will cause the sintering process to fail. Great care must be taken to ensure the cleanliness of the diamond input and any binder or catalyst-solvent metal added prior to sintering.
[000101] To prepare for sintering, clean diamond input, substrate and container components are prepared for loading. The diamond input and the substrate are placed in a refractory metal container called a “can” that will seal its contents against external contamination. The diamond input and substrate will remain in the can as long as it is sintered at high temperature and high pressure to form a polycrystalline diamond compact. The can can be sealed by electron beam welding at an elevated temperature and in a vacuum.
[000102] Sufficient diamond aggregate (powder or grain of sand) is loaded to account for linear shrinkage during sintering at elevated temperature and elevated pressure. The method used for loading diamond input into a sintering can affects the overall shape and tolerances of the final part. In particular, the packing density of the input diamond across the high should be as uniform as possible to produce a good quality sintered polycrystalline diamond compact structure. When loading, diamond bonding can be avoided by adding and staging in stages.
[000103] The degree of uniformity in the density of the input material after loading will affect the geometry of the PDC. The load of the input diamond in a dry form versus the load of diamond combined with a binder and the subsequent process applied for the removal of the binder will also affect the characteristics of the finished PDC. To properly pre-compact diamond for sintering, pre-compact pressures must be applied under isostatic conditions. Selection of substrate material
[000104] The properties of unique diamond material and their relative differences in modulus and CTE compared to the most potential substrate material diamond make the selection of an appropriate polycrystalline diamond substrate a formidable task. A wide disparity in material properties between the diamond and the substrate creates challenges for the successful manufacture of a PDC with the displayed strength and durability. Even very hard substrates appear to be soft compared to PCD. The substrate and diamond must be able to withstand not only sintering pressure and temperature, but must be able to return to room temperature and atmospheric pressure without delamination, cracking or otherwise failing.
[000105] The selection of substrate material also requires consideration of the intended application for the part, impact strength and resistances displayed, and the amount of catalyst-solvent metal that will be incorporated into the diamond table during sintering. Substrate materials must be selected with material properties that are compatible with those in the diamond table to be formed. Substrate geometry
[000106] In addition, it is important to consider whether to use a substrate that has a smooth surface or a surface with topographic characteristics. Substrate surfaces can be formed with a variety of topographic characteristics so that the diamond table is attached to the substrate with either a chemical bond or a mechanical grip. The use of topographic features on the substrate provides a larger surface area for chemical bonds and with the mechanical grip provided by the topographic features, it can result in a stronger and more durable component. Sample materials and manufacturing steps
[000107] The inventors discovered and determined materials and manufacturing processes to build PDCs for use in a joint and modular support insert. It is also possible to manufacture the surfaces invented by methods and to use materials other than those listed below.
[000108] The steps described below, such as selection of substrate material and geometry, selection of diamond input, loading and sintering methods, will affect each other, even though they are listed as separate steps that must be taken to manufacture a PDC or a polycrystalline cubic boron nitride compact, no step is completely independent of the others, and all steps must be standardized to ensure the success of the manufacturing process. Selection of substrate material and / or catalyst-solvent metal
[000109] To manufacture any polycrystalline component, an appropriate substrate must be selected (unless the component must be independent without a substrate). Table 2 - some substrates for prosthetic joint applications


[000110] The CoCr used as a substrate in the catalyst-solvent metal can be CoCrMo or CoCrW or another appropriate CoCr. Alternatively, an Fe-based alloy, a Ni-based alloy (such as Co — Cr — W — Ni) or another alloy can be used. Co and Ni alloys tend to provide a corrosion resistant component. The above substrates and catalyst-solvent metals are examples only. In addition to these substrates, other materials may be suitable for use as substrates for the construction of modular support inserts and joints and other surfaces.
[000111] When titanium is used as the substrate, it is possible to put a thin tantalum barrier layer on the titanium substrate. The tantalum barrier prevents mixing of titanium alloys with cobalt alloys used in the diamond input. If the titanium alloys and cobalt alloys mix, it is possible that a detrimentally low melting eutectic intermetallic compound will be formed during the high temperature and high pressure sintering process. The tantalum barrier bonds to both titanium and copper alloys, and to the PDC that contains cobalt-catalyst-solvent metals. Thus, a PDC made using a titanium substrate with a tantalum barrier layer and diamond input that has cobalt catalyst-solvent metals can be very strong and well formed. Alternatively, the titanium substrate can be provided with an alpha box oxide coating (an oxidation layer forming a barrier that prevents the formation of a eutectic metal.
[000112] If a cobalt chromium molybdenum substrate is used, a thin tungsten layer or a thin cobalt and tungsten layer can be placed on the substrate before loading the diamond input to control the formation of chromium carbide (CrC) during sintering.
[000113] In addition to those listed, other suitable substances can be used to form PDC surfaces. In addition, it is possible within the scope of the claims to form a diamond surface for use without a substrate. It is also possible to form a surface from any of the super hard materials and other materials listed here, in which case a substrate may not be necessary. In addition, if it is desirable to use a type of diamond or carbon other than PCD, the substrate selection may differ. For example, if a diamond surface is to be created by using a chemical vapor deposit or physical vapor deposit, then the use of an appropriate substrate for those manufacturing environments and for the compositions used will be necessary. Determination of substrate geometry
[000114] A substrate geometry suitable for the compact to be manufactured and suitable for the materials being used must be selected. To manufacture a non-concave acetabular cup, a convex non-flat femoral head, or a non-flat surface, it is necessary to select a substrate geometry that will facilitate the manufacture of these parts. To ensure proper diamond formation and to avoid compact distortion, forces acting on the diamond and the substrate during sintering must be strictly radial. Therefore, the substrate geometry on the contact surface with diamond input to manufacture an acetabular cup, a femoral head, or any other non-flat component is generally non-flat.
[000115] As mentioned earlier, there is a wide disparity in the characteristics of synthetic diamond material and substrate materials most available. In particular, module and CTE are of concern. However, when applied in combination with each other, some substrates can form a stable and strong PDC. The table below lists physical properties of some substrate materials. Table 3A - material properties of some substrates


[000116] The use of cobalt or titanium chrome substrates individually for the manufacture of non-flat PDCs can result in cracking of the diamond table or separation of the substrate from the diamond table. In particular, it appears that the dominant property of titanium during sintering at high pressure and high temperature is compressibility while the dominant property of chromium cobalt during sintering is CTE. In some embodiments, a substrate of two or more layers can be used to obtain dimensional stability during and after manufacture.
[000117] In several embodiments, a single layer substrate can be used. In other embodiments, a two-layer substrate can be used, as discussed. Depending on the properties of the components being used, however, it may be desired to use a substrate that includes three, four or more layers. Such multi-layered substrates are intended to fall within the scope of the claims. Substrate surface topography
[000118] Depending on the application, it may be advantageous to include topographic characteristics of substrate surface in a substrate that must be formed in a PDC. Regardless of whether a one-piece, two-piece or multi-piece substrate is used, it may be desirable to modify the surface of the substrate or provide topographic characteristics on the substrate to increase the total diamond surface area to increase the substrate contact with diamond and provide a mechanical grasp of the diamond table.
[000119] The placement of topographic features on a substrate serves to modify the substrate surface geometry or contours than the substrate surface geometry or contours would have formed as a simple non-planar or flat figure. Topographic characteristics of substrate surface may include one or more different types of topographic characteristics that result in protruding, notched or contoured characteristics that serve to increase the surface, mechanically lock the diamond table to the substrate, prevent crack formation or prevent crack propagation. .
[000120] Topographic characteristics of substrate surface or substrate surface modifications serve a variety of useful functions. The use of substrate topographic characteristics increases the total substrate surface contact area between the substrate and the diamond table. this increased surface contact area between diamond table and substrate results in a greater total number of chemical bonds between diamond table and substrate than if the topographic characteristics of the substrate surface were absent, thereby obtaining a stronger PDC.
[000121] The topographic characteristics of the substrate surface also serve to create a mechanical lock between the substrate and the diamond table. Mechanical locking is achieved by the nature of the topographic characteristics of the substrate and also increases the strength of the PDC.
[000122] Topographic characteristics of substrate surface can also be used to distribute the residual stress field of the PDC over a larger surface area and over a larger volume of diamond and substrate material. This larger distribution can be used to keep the stresses below the threshold for crack initiation and / or crack propagation at the diamond substrate / table interface, the diamond itself and the substrate itself.
[000123] Topographic characteristics of substrate surface increase the depth of the gradient interface or transition zone between diamond table and substrate, to distribute the residual stress field across a longer segment of the compact composite structure and obtain a more strong.
[000124] Substrate surface modifications can be used to create a sintered PDC that has residual stresses that strengthen the strength of the diamond layer and provide a more robust PDC with greater break resistance than if no topographic surface characteristics were used. This is because to break the diamond layer, it is necessary to first overcome the residual stresses in the part and then to overcome the resistance of the diamond table.
[000125] Topographic characteristics of substrate surface redistribute forces received by the diamond table. topographic characteristics of the substrate surface cause a force transmitted through the diamond layer to be relayed from a single force vector over multiple force vectors. This redistribution of forces shifting to the substrate avoids conditions that would deform the substrate material at a faster rate than the diamond table, as such differences in deformation can cause cracking and failure of the diamond table.
[000126] Topographic characteristics of substrate surface can be used to decrease the intensity of the tension field between the diamond and the substrate to obtain a stronger part.
[000127] Topographic characteristics of substrate surface can be used to distribute the residual stress field throughout the PDC structure to reduce the stress per volume of the structure unit.
[000128] Topographic characteristics of substrate surface can be used to mechanically lock the diamond table to the substrate by causing the substrate to compress over one edge of the diamond table during manufacture. Swallowtail, non-plant and lentate modifications act to provide force vectors that tend to compress and increase the diamond table and substrate interface during cooling as the substrate expands radially.
[000129] Topographic characteristics of substrate surface can also be obtained to obtain a manageable shape. as mentioned here, differences in coefficient of thermal expansion and modulus between diamond and the chosen substrate can result in failure of the PDC during manufacturing. For certain parts, the strongest interface between substrate and diamond table that can be obtained when topographic substrate characteristics are used can obtain a polycrystalline diamond compact that can be successfully manufactured. However if a similar part of the same dimensions is to be made using a substrate with a simple substrate surface instead of specialized topographic substrate surface characteristics, the diamond table may crack or separate from the substrate due to differences in coefficient of thermal expansion or diamond module and substrate.
[000130] Examples of useful topographic substrate surface characteristics include waves, notches, ridges, other longitudinal surface characteristics (any of which can be arranged longitudinally, latitudinally, crossing each other at a desired angle, in random patterns and in patterns geometric), three-dimensional textures, non-flat segment depressions, non-flat segment protuberances, triangular depressions, arcuate depressions, arcuate depressions, partially non-flat depressions, partially non-flat protuberances, cylindrical depressions, cylindrical depressions, rectangular depressions rectangular, polygonal shaped depressions of side n where n is an integer, protrusions of polygonal shape of side n, a pattern of crest inserts, an iron pattern of protruding structures, dimples, nozzles, protuberances, ribs, fenestrations cutouts the ridges or ridges that have a cross-sectional shape that is rounded, triangular, arched, square, polygonal, curved or otherwise, or other shapes. Machining, pressing, extrusion, drilling, injection molding and other manufacturing techniques to create such shapes can be used to obtain desired substrate topography. Illustration of topographic characteristics of example substrate is found in US patent no. 6,709,463 which is hereby incorporated as a reference in its entirety.
[000131] Although many substrate topographies have been represented on convex non-flat substrates, those surface topographies can be applied to convex non-flat substrate surfaces, other non-flat substrate surfaces, and flat substrate surfaces. Substrate surface topographies that are variations or modifications of those shown, and other substrate topographies that increase the strength or durability of the component can also be used. Diamond input selection
[000132] It is predicted that typically the diamond particles used will be in the range of less than 1 micron to more than 100 microns. In some embodiments, however, diamond particles as small as 1 nanometer can be used. Smaller diamond particles are preferred for smoother surfaces. Commonly, diamond particle sizes will be in the range of 0.5 to 2.0 microns or 0.1 to 10 microns.
[000133] An example diamond input is shown in the table below. Table 3B - Example bimodal diamond input

[000134] This formulation mixes some smaller and some larger diamond crystals so that during sintering, the small crystals can dissolve and then recrystallize to form a lattice structure with the larger diamond crystals. Titanium carbonitride powder can be optionally included in the diamond input to prevent excessive diamond grain growth during sintering to produce a finished product that has smaller diamond crystals.
[000135] Another example of a diamond input is provided in the table below. Table 4- Example trimodal diamond input

[000136] The trimodal diamond input described above can be used with any appropriate diamond input having a first size or diameter “x”, a second size 0.1 times, and a third size 0.01 times. This ratio of diamond crystals allows conditioning of the input up to approximately 89% of theoretical density, closing most of the interstitial spaces and providing the most dense diamond table in the finished polycrystalline diamond compact.
[000137] Another example of a diamond input is provided in the table below. Table 5 - example trimodal diamond input
Another example of a diamond input is provided in the table below. Table 6 - example trimodal diamond input

[000138] Another example of a diamond input is provided in the table below. Table 7 - example trimodal diamond input

[000139] In some embodiments, the diamond input used will be diamond dust having a larger dimension of approximately 100 nanometers or less. In some embodiments, some catalyst-solvent metal is included with the diamond input to aid in the sintering process, although in many applications there is a significant sweep of catalyst-solvent metal from the substrate during sintering as well. Solvent metal selection
[000140] It has already been mentioned that solvent metal will sweep the substrate through the diamond input during sintering to solvate some diamond crystals so that they can later recrystallize and form a diamond-diamond lattice network that characterizes PCD. In the event of making a PCD-independent compact without a substrate, solvent metal can be mixed with diamond crystals before sintering to achieve the same result. Even if a substrate is being used, it is possible to include some catalyst-solvent metal in the diamond input when desired to supplement the sweep of catalyst-solvent metal from the substrate.
[000141] Traditionally, cobalt, nickel and iron were used as solvent metals to make PCD. Platinum and other materials could also be used for a binder.
[000142] CoCr can be used as a catalyst-solvent metal to sinter PCD to obtain a more wear-resistant PDC. Infiltration of diamond particles with Cobalt (Co) metal produces standard PDC. As cobalt infiltrates the diamond, carbon is dissolved (mainly from the smaller diamond grains) and re-precipitates over the larger diamond grains causing the grains to grow together. This is known as liquid phase sintering. The remaining pore spaces between the diamond grains are filled with cobalt metal.
[000143] In one example, the cobalt chromium alloy (CoCr) can be used as the solvent metal that acts similarly to the metal Co. however, it differs in that the CoCr reacts with some of the dissolved carbon resulting in the precipitation of CoCr carbides . These carbides, like most carbides, are harder (abrasion resistant) than cobalt metal and result in a PDC that is more resistant to abrasion or wear.
[000144] Other metals can be added to Co to form metal carbides as precipitates in the pore spaces between the diamond grains. These metals include the following, but not limited to, Ti, W, Mo, V, Ta, Nb, Zr, Si and combinations thereof.
[000145] It is important not only to add the solvent metal to the diamond input, but also to include solvent metal in an appropriate proportion and mix it evenly with the input. The use of approximately 86% diamond input and 15% solvent metal per mass (weight) provided good results, other reasons for diamond input to solvent metal may include 5:95, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 65:35, 75:25, 80:20, 90:10, 95: 5, 97: 3, 98: 2, 99: 1, 99, 5: 0, 5, 99, 7: 0, 3, 99, 8: 0, 2, 99.9: 0.1 and others.
[000146] To mix the diamond input with catalyst-solvent metal, first the quantities of input and solvent metal to be mixed can be put together in a mixing vessel, like a mixing vessel made of the catalyst-solvent metal wanted. Then the combination of input and solvent metal can be mixed at an appropriate speed (such as 200 rpm) with dry methanol and attritor spheres for an appropriate period of time, such as 30 minutes. the attractor spheres, the mixing device and the mixing container can be made of the catalyst-solvent metal. The methanol can then be decanted and the diamond input separated from the attractor spheres. The input can then be dried and cleaned by burning in a molecular hydrogen oven at approximately 1000 degrees Celsius for approximately 1 hour. the input is then ready for loading and sintering. Alternatively, it can be stored in conditions that will keep it very clean. Suitable ovens that can be used to burn also include hydrogen plasma ovens and vacuum ovens. Diamond Input Load
[000147] With reference to figure 1E, an apparatus for carrying out a charging technique is shown. The apparatus includes a spinning rod 151 with a longitudinal geometric axis 152, the fixing rod being able to spin around its longitudinal geometric axis. The spinning rod 151 has an end 153 matched to the size and shape of the part to be manufactured. For example, if the part to be manufactured is non-flat, the spinning rod end 153 may be non-flat.
[000148] A compression ring 154 is provided with a hole 155 through which the spinning rod 151 can project. A die 156 can be provided with a cavity 157 also matched to the size and shape of the part to be made.
[000149] To load diamond input, the spinning rod is placed in a drill chuck and the spinning rod is aligned with the central point of the die. The depth at which the spinning rod stops in relation to the matrix cavity is controlled with a clamping screw and monitored with a dial indicator.
[000150] The matrix is loaded with a known quantity of diamond input material. The spinning rod is then rotated around its longitudinal geometric axis and lowered into the die cavity to a predetermined depth. The spinning rod contacts and rearranges the diamond input during this operation. Then the spinning rod wiring is stopped and the spinning rod is locked in place.
[000151] The compression ring is then lowered around the outside of the spinning rod to a point where the compression ring contacts diamond input in the matrix cavity. The part of the compression ring that contacts the diamond is annular. The compression ring is tapped up and down to compact the diamond. This type of compaction is used to distribute diamond material throughout the cavity at the same density and can be done in stages to avoid bonding. The conditioning of the diamond with the compaction ring makes the density of the diamond around the sample equator very uniform and the same as that of the polar region in the cavity. In this configuration, the diamond sinters in a truly non-flat way and the resulting part maintains its sphericity at close tolerances. Control of large volumes of powder inputs, such as diamond
[000152] The following information provides additional instruction on control and preprocessing of diamond input before sintering polycrystalline cubic boron nitride (PCBN) and PDC powders reduce in volume during the sintering process. The amount of shrinkage experienced depends on several factors such as: 1. The amount of metal mixed with the diamond. 2. The charge density of the powders. 3. The volume density of diamond metal mixing. 4. The volume of powder loaded. 5. Particle size distribution (PSD) of the powders.
[000153] In most PDC and PCBN sintering applications, the volume of powder used is small enough that shrinkage is easily controlled, as shown in figure 3A-1. Figure 3A-1 illustrates a can 3A-54 in which halves of can 3A-53 contain a substrate 3A-52 and a diamond table 3A-51. However, when sintering large volumes of diamond powders in spherical configurations, shrinkage is large enough to cause deformation of the 3A-66 containment cans as shown in figure 3A-2 and the cross section of figure 3A-3. The diamond sintered 3A-75 but the can has 3A-77 deformations and 3A-78 wrinkles, resulting in a non-uniform and damaged part. The following method is an improved method of loading, pre-compressing, densifying and sealing refractory can for spherical and non-flat parts loaded with large volumes of diamond and / or metal powders. The processing steps are described below.
[000154] With reference to figure 3A-4 and its cross section in figure 3A-5, PDC or PCBN powders 3A-911 are loaded against a 3A-99 substrate and into a 3A refractory metal containment assembly -913 having 3A-910 half coatings and a 3A-912 seal. Extra powder can be loaded perpendicular to the splice in the can to accommodate shrinkage.
[000155] With reference to figure 3A-6, a can assembly 3A-913 is placed in a compacting device 3A-1014, which can be a cylindrical support or slide 3A-1015 with two hemispherical punches 3A-1016 and 3A- 1017. The device is designed to support the containment cans and allow the 3A-910 can half liners to slide into the seam during the pressing operation.
[000156] With reference to figure 3A-7-1, the relationship of the half can coatings 3A-910 with the junction 3A-91 and the hole punch 3A-1016 is seen.
[000157] With reference to figure 3A-7, a compacting device 3A-1014 is illustrated with a can 3A-913 placed in a press 3A-1218 and the upper punches 3A-1016 and lower 3A-1017 compress the can assembly 3A-913. The containment can halves 3A-910 slide one after the other avoiding deformation while the powdered input is compressed.
[000158] With reference to figure 3A-8, the upper punch 3A-24 and upper press connection 3A-25 are retracted and a crimping die 3A-20 is fixed to the cylinder of the compaction device 3A-21. The can assembly 3A-913 rests against the lower punch 3A-22 which is attached to the lower press connection 3A-23.
[000159] With reference to figures 3A-9 and 3A-9-1, the lower punch 3A-22 is raised towards the upper punch 3A-24, pushing excess can material 3A- 27 into the hemispheric portion of the matrix. curl 3A-19 by folding the excess around the top can 3A-26.
[000160] With reference to figure 3A-10, the lower punch is raised by expelling the can assembly 3A-13 from the cylinder 3A-28 of the compacting device 3A-21.
[000161] With reference to figure 3A-11, the can assembly 3A-913 emerges from the spherical compression operation with high load density. The part can then be sintered in a cubic or other press without deformation or breakage of the containment cans as the 3A-190 Latvian half liners are superimposed. General connection of diamond input
[000162] Another method that can be used to maintain a uniform density of the input diamond is the use of a binder. A binder is added to the correct volume of the input diamond, and then the combination is compressed into a can. Some binders that can be used include polyvinyl butyryl, polymethyl methacrylate, polyvinyl formaldehyde, polyvinyl chloride acetate, polyethylene, ethyl cellulose, methyl abietate, paraffin wax, polypropylene carbonate and polyethyl methacrylate.
[000163] In one embodiment, the process of connecting a diamond input includes four stages. First, a binder solution is prepared. A binder solution can be prepared by adding approximately 5 to 25% plasticizer in poly (propylene carbonate) pellets and dissolving this mixture in solvent such as 2-butanone to make approximately 20% by weight solution.
[000164] Plasticizers that can be used include generically non-aqueous binders, glycol, dibutyl phthalate, benzyl butyl phthalate, benzyl alkyl phthalate, diethyl hexyl phthalate, diisoecyl phthalate, diisononyl phthalate, diethyl phthalate, dipropylene dibenzoate glycol, mixed glycols dibenzoate, 2-ethyl hexyl diphenyl dibenzoate, mixed glycols dibenzoate, 2-ethyl hexyl diphenyl phosphate, diphenyl isodecyl phosphate, diphenyl isodecyl phosphate, tricrestyl phosphate ethyl ethoxide, adipoxy phosphate and adip , triisooctyl trimellitate, dioctyl phthalate, epoxidized linseed oil, epoxidized soybean oil, triethyl acetyl citrate, propylene carbonate, various phthalate esters, butyl stearate, glycerin, polyalkyl glycol derivatives, diethyl oxalate, wax paraffin and triethylene glycol. Other suitable plasticizers can also be used.
[000165] Solvents that can be used include 2-butanone, methylene chloride, chloroform, 1,2-dichloroethane, trichlorethylene, methyl acetate, ethyl acetate, vinyl acetate, propylene carbonate, n-propyl acetate, acetonitrile , dimethyl formamide, propionitrile, n-methyl-2-pyrrolidene, glacial acetic acid, dimethyl sulfoxide, acetone, methyl ethyl ketone, cycloxanone, oxisolve 80a, caprotactone, butyralactone, tetrahydrofuran, 1,3-dioxane, propylene oxide, acetate of celosolve, 2-methoxy ethyl ether, benzene, styrene, xylene, ethanol, methanol, toluene, cyclohexane, chlorinated hydrocarbons, esters, ketones, ethers, ethyl benzene and various hydrocarbons. Other suitable solvents can be used as well.
[000166] Second, diamond is mixed with the binder solution. Diamond can be added to the binder solution to obtain approximately 2-25% binder solution (the percentage is calculated without considering 2-butanone).
[000167] Third, the mixture of diamond and binder solution is dried. This can be accomplished by placing the binder and diamond solution mixture in a vacuum oven for approximately 24 hours at approximately 50 degrees Celsius to propel out any 2-butanone solvent.
[000168] Fourth, the diamond and binder can be compressed into shape. When the diamond and binder are removed from the oven, they will be in a lump that can be broken into pieces that are then pressed into the desired shape with a compacting press. A press axis of the desired geometry can be contacted with the diamond connected to form it in a desired shape. When the diamond and binder have been pressed, the shaft is retracted. The final density of diamond and binder after pressing can be at least approximately 2.6 grams per cubic centimeter.
[000169] If a volatile binder is used, it must be removed from the diamond formed before sintering. The formed diamond is placed in an oven and the bonding agent is aerated or pyrolyzed for a sufficient period of time so that there is no binder remaining. The quality of PDC is reduced by strange contamination of the diamond or substrate, and great care must be taken to ensure that contaminants and binder are removed during the kiln cycle. The combination of temperature and elevation time is critical for effective binder pyrolysis. For the binder example given above, the deglutinating process can be used to remove the binder as follows. (see figure 1F while reading this description can be useful).
[000170] First, the formed diamond and binder are heated from room temperature to approximately 500 degrees Celsius. The temperature can be increased by approximately 2 degrees Celsius per minute until approximately 500 degrees Celsius is reached. Second, the temperature of the formed and bonded diamond is maintained at approximately 500 degrees Celsius for approximately 2 hours. Third, the temperature of the diamond is raised again. The temperature can be increased from approximately 500 degrees Celsius by approximately 4 degrees per minute until a temperature of approximately 950 degrees Celsius is reached. Fourth, the diamond is kept at approximately 950 degrees Celsius for approximately 6 hours. Fifth, the diamond is then allowed to return to room temperature at a temperature drop of approximately 2 degrees per minute.
[000171] In some embodiments, it may be desirable to pre-form a diamond input bonded by an appropriate process, such as injection molding. The diamond input may include diamond crystals of one or more sizes, catalyst-solvent metal, and other ingredients to control diamond recrystallization and distribution of catalyst-solvent metal. The manipulation of the diamond input is not difficult when the desired final curvature of the part is flat, convex or conical dome. However, when the desired final curvature of the part has complex contours, as illustrated here, providing the uniform thickness and contour accuracy of the PDC is more difficult when using powdered diamond input. In such cases, it may be desirable to preform the diamond input before sintering.
[000172] If it is desirable to pre-form a diamond input before loading it into a sintering can, instead of placing powdered diamond input in the can, the steps described here and variations thereof can be followed. First, as already described, a suitable binder is added to the diamond input. Optionally, powdered catalyst-solvent metal and other components can be added to the input as well. The binder will typically be a polymer chosen for certain characteristics, such as melting point, solubility in various solvents, and CTE. One or more polymers can be included in the binder. The binder can also include an elastomer and / or solvents as desired to obtain desired binding, fluid flow and injection molding characteristics. The working volume of the binder to be added to an input can be equal to or slightly greater than the measured volume of void space in an amount of lightly compressed powder. Since binders typically consist of materials such as organic polymers with relatively high CTEs, the workload should be calculated for the expected injection molding temperatures. The binder and input must be mixed thoroughly to ensure uniformity of composition. When heated, the binder and input will have sufficient fluid character to flow in high pressure injection molding. The heated input and binder mixture is then injected under pressure into molds of the desired shape. The molded part then cools in the mold until it hardens, and the mold can then be opened and the part removed. Depending on the desired final PDC geometry, one or more components of molded diamond input can be created and placed in a PDC sintering can. In addition, the use of this method allows the diamond input to be molded into a desired shape and then stored for long periods of time before use in the sintering process, thereby simplifying manufacturing and resulting in more efficient production.
[000173] As desired, the binder can be removed as an injection-molded diamond input. A variety of methods are available to achieve this. For example, by treating the furnace with hydrogen or simple vacuum, the binder can be removed as a diamond input. In such a method, the form would be brought to a desired temperature in a vacuum or in a very low pressure hydrogen (reduction) environment. The binder will then volatilize with increasing temperature and be removed from the form. The form can then be removed from the oven. When hydrogen is used, it helps to maintain extremely clean and chemically active surfaces in diamond crystals in the form of a diamond input.
[000174] An alternative method for removing the binder from the form involves using two or polymer binders (such as polyethylene) with different molecular weights. After initial injection molding, the diamond input form is placed in a solvent bath that removes the lower molecular weight polymer, leaving the higher molecular weight polymer to maintain the shape of the diamond input shape. Then the diamond input form is placed in an oven for the treatment of very low pressure hydrogen or vacuum to remove the higher molecular weight polymer.
[000175] Removal of partial or complete binder from the diamond input form can be performed before assembling the form in a pressure assembly for PDC sintering. Alternatively, the pressure assembly including the diamond input form can be placed in an oven for the treatment of a very low pressure hydrogen oven or vacuum and removal of binder. Diluted binder
[000176] In some embodiments, diluted binder can be added to PCD, PCBN or ceramic powders to maintain shape. This technique can be used to provide an improved method of forming powders of PDC, PCBN, ceramic or cermet in layers of various geometries. A PDC, PCBN, ceramic or cermet powder can be mixed with a temporary organic binder. This mixture can be mixed and fused or calendered on a sheet (ribbon) of the desired thickness. The sheet can be dried to remove water or organic solvents. The dry tape can then be cut into shapes necessary to conform to the geometry of a corresponding substrate. The tape / substrate assembly can then be heated in a vacuum oven to expel the binder material. The temperature can then be raised to a level where the cermet or ceramic powder melts with itself and / or with the substrate, thereby producing a uniform continuous cermet or ceramic coating attached to the substrate.
[000177] With reference to figure 5, a matrix 55 with a cup / can in it 54 and diamond input 52 against it are represented. A hole punch 53 is used to form diamond input 52 in a desired shape. Binder liquid 51 is not added to the powder until after the diamond, PCBN powder, ceramic or cermet 52 is in the desired geometry. Dry powder 52 is formed by spinning using a rotary formed hole punch 53 in a refractory containment can 54 sustained in a holding matrix 55. In another method shown in figure 6, input powder 62 is added to a mold 66. A hole punch forms the input in the format. A vibrator 67 can be used to help the powder 62a take the shape of the mold 66. After the powder input is in the desired geometry, a diluted solution of an organic binder with a solvent is allowed to infiltrate through the powder granules.
[000178] As shown in figures 7 and 8, a layer of powder 88 can be loaded, and after a few minutes, when the binder is sufficiently cured at room temperature, another layer 89 can be loaded on top of the first layer 88. This method it is particularly useful in the production of PDC or PCBN with multiple layers of varying powder particle size and metal content. The process can be repeated to produce as many layers as desired. Figure 7 shows a sectional view of a spherical powder load, in multi-layers using a first layer 88, second layer 89, third layer 810, and final layer 811. The binder content must be kept to a minimum to produce good charge density and limit the amount of gas produced during the binder removal phase to reduce the tendency of the containment cans 84 to be displaced from an accumulation of internal pressure.
[000179] After all the layers of powder are loaded, the binder can be burned in a vacuum oven in a vacuum of approximately 200 milliliters or less and at the desired time and temperature profile, as shown in figure 9. An acceptable binder is 0.5 to 5% propylene carbonate in methyl ethyl ketone. An example binder firing cycle can be used to remove binder as follows:
Gradients
[000180] Diamond input can be selected and loaded to create different types of gradients in the diamond table. These include an interface gradient diamond table, an incremental gradient diamond table, and a continuous gradient diamond table.
[000181] If a single type or mixture of diamond input is loaded adjacent to a substrate, as discussed elsewhere here, sweeping catalyst-solvent metal across the diamond will create an interface gradient in the table's gradient transition zone diamond.
[000182] An incremental gradient diamond table can be created by loading diamond inputs of different characteristics (diamond particle size, diamond particle distribution, metal content, etc.) into different strata or layers before sintering. For example, a substrate is selected, and a first diamond input containing 60% catalyst-solvent metal by weight is loaded into a first layer adjacent to the substrate. Then, a second diamond input containing 40% catalyst-solvent metal by weight is loaded into a second layer adjacent to the first layer. Optionally additional strata of diamond input can be used. For example, a third layer of diamond input containing 20% catalyst-solvent metal by weight can be loaded adjacent to the second layer.
[000183] A continuous gradient diamond table can be created by loading diamond input in a way that one or more of its characteristics vary continuously from one depth in the diamond table to another. For example, diamond particle size can vary from large near a substrate (to create large interstitial spaces in the diamond for catalyst-solvent metal to sweep in) to small near the diamond surface to create a part that is strongly bonded to the substrate but has a very low friction surface.
[000184] Diamond inputs from different strata can be of the same or different diamond particle size and distribution. Solvent-catalyst metal can be included in the diamond input of the different decks in weight percentages from approximately 0% to more than approximately 80%. In some embodiments, diamond input will be loaded without catalyst-solvent metal in it, relying on sweeping catalyst-solvent metal from the substrate to obtain sintering. The use of a plurality of diamond input strata, strata having different diamond particle size and distribution, different catalyst-solvent metal in weight, or both, allows a diamond table to be made that has different physical characteristics in the interface with the substrate than on the surface. This allows a PDC to be manufactured that has a diamond table very tightly attached to its substrate. Bisquing processes to retain formats
[000185] If desired, a bisquing process can be used to retain formats for subsequent processing of PDCs, PCBN, and ceramic or cermet products. This involves an interim processing step in high pressure high temperature (HTHP) sintering of PDC, PCBN, ceramic or cermet powders called “bisquing”. Bisquing can provide the following improvements to the processing of the above products: A. Pre-sintered shapes can be controlled that are in a certain density and size B. Product consistency is improved dramatically. C. Formats can be easily manipulated in bisque form. D. In layered constructions, bisquing prevents the different layers from contaminating each other. E. Bisquing different layers or components separately increases the separation of working elements increasing the quality and efficiency of production. F. Bisquing molds are often easier to manipulate and control before final assembly of the smaller final product forms.
[000186] Containers or bisquing molds can be manufactured from any material at an elevated temperature that has a higher melting point than the highest melting point of any mixing component to be bisqued. Bisque mold / container materials that work well are graphite, quartz, solid hexagonal boron nitride (HBN) and ceramic. Some refractory metals (high temperature stainless steel, Nb, W, Ta, Mo, etc.) work well in some applications where bisquing temperatures are lower and adhesion of the bisque powder mixture is not a problem. Molds or containers can be molded by compression, forming, or machining, and can be polished at the interface between the bisque material and the container / mold itself. Some container / mold materials require glazing and / or firing prior to use.
[000187] Figure 10 shows a method 1006 for making a cylinder with a concave or trough relief using the bisquing process. Pre-mixed powders of PDC, PCBN, ceramic materials or cermet 1001 that contain enough metal to be subjected to solid phase sintering are loaded into the bisquing molds or containers 1002 and 1004. A release agent may be required between the container / mold to ensure that the final bisque shape can be removed after firing the oven. Some release agents that can be used are HBN, graphite, mica and diamond powder. A bisque container / mold lid with an integral support shape 1005 is placed over the loaded powder material to ensure that the material retains the shape during the sintering process. The bisque container / mold assembly is then placed in a hydrogen atmosphere furnace, or alternatively, a vacuum furnace that is pulled at a vacuum that ranges from 200 to 0 Millitorrs. The charge is then heated within a range of 0.6 to 0.8 of the melting temperature of the larger volume mix metal. A typical oven cycle is shown in figure 12. After the oven cycle is completed and the container / mold is cooled, hardened bisque powders can be removed for further HPHT processing. One form of input bisque 1003 is the liquid product.
[000188] Figure 11 shows fabrication 1110 of a bisque shape for a total hemispherical part 1109 that has multiple layers of powder 1107a and 1107b. premixed powders of PDC, PCBN, ceramic or cermet materials that contain enough metal to undergo solid phase sintering are loaded into the 1108 bisquing molds or containers. A release agent may be required between the mold / container to ensure that the final bisque shape can be removed after firing in an oven. The container / bisque mold assembly can then be placed in a vacuum oven that is pulled at a vacuum ranging from 200 to 0 millitorrs. The charge is then heated within a range of 0.6 to 0.8 of the melting temperature of the larger volume mix metal. After the oven cycle is completed and the container / mold is cooled, the hardened bisque powders 1109 can be removed for further HPHT processing. An example of a bisque binder firing cycle that can be used to remove unwanted materials before sintering is as follows:
Reduction of free volume in diamond input
[000189] As mentioned earlier, it may be desirable to remove free volume in the diamond input before sintering is attempted. The inventors have found this to be a useful procedure when producing non-flat convex and concave parts. If a press with sufficient anvil displacement is used for sintering at high temperature and high pressure, however, this step may not be necessary. Free volume in the diamond input will be reduced so that the resulting diamond input is at least approximately 95% theoretical density and closer to approximately 97% theoretical density.
[000190] With reference to figures 1GA and 1G, an assembly used to pre-compress diamond to eliminate free volume is represented. In the drawing, the diamond input is intended to be used to make a part of non-convex polycrystalline diamond. The assembly can be adapted to pre-compress diamond input to make PDCs of other complex shapes.
[000191] The assembly shown includes a hub 161 of a pressure transfer medium. A cube is made of pyrophyllite or other pressure transfer material suitable as a synthetic pressure medium and is intended to be subjected to pressure from a cubic press with anvils simultaneously pressing the six faces of the cube. A cylindrical cell instead of a hub can be used if a belt press is used for this step.
[000192] Cube 161 has a cylindrical cavity 162 or passage through it. The center of the cavity 162 will receive a non-flat refractory metal can 170 loaded with diamond input 166 which must be pre-compressed. Diamond input 166 may have a substrate with it.
[000193] Can 170 consists of two non-plant can halves 170a and 170b, one of which overlaps the other to form a light ferrule 172. The can can be a suitable refractory metal such as niobium, tantalum, molybdenum, etc. the can is typically two hemispheres, one that is slightly larger to accept the other being slid into it to fully enclose the diamond input. A recessed area or ferrule is provided in the larger can so that the smaller can will fit satisfactorily inside. The seam of the can is sealed with an appropriate seal such as dry hexagonal boron nitride or a synthetic compression medium. The seal forms a barrier that prevents the salt pressure medium from entering the can. The can splice can also be welded by plasma, laser or electron beam processes.
[000194] An appropriately molded pair of salt domes 164 and 167 surround the canister 170 containing the diamond input 166. In the example shown, the salt domes individually have a non-flat cavity 165 and 168 to receive the canister 170 containing the input non-flat diamond 166. The salt domes and the diamond can and input are assembled together so that the salt domes enclose the diamond input. A pair of cylindrical salt disks 163 and 169 are mounted on the outside of the salt domes 164 and 167. All the components mentioned above fit into the hole 162 of the pressure medium cube 161.
[000195] The entire pyrocube assembly is placed in a press and pressurized under the appropriate pressure (such as approximately 40-68 Kbar) and for an appropriate although brief duration to pre-compress the diamond and prepare it for sintering. No heat is needed for this step. Mold releases
[000196] When making non-flat shapes, it may be desirable to use a mold in the sintering process to produce the desired liquid shape. Metal CoCr can be used as a mold release in the formation of molded diamond or other super hard products. The sintering of super hard powder inputs to a substrate, whose purpose is to support the resulting super hard table, can be used to produce standard PDC and PCBN pates. However, in some applications it is desired to remove the diamond table from the substrate.
[000197] With reference to figure 14, a diamond layer 1402 and 1403 was sintered on a substrate 1401 on an interface 1404. Interface 1404 must be broken to result in independent diamond if the substrate is not required in the final product. A mold release can be used to remove the substrate from the diamond table. If CoCr alloy is used for the substrate, then CoCr itself serves as a mold release, as well as serving as a catalyst-solvent metal. CoCr works well as a mold release because its CTE is dramatically different from that of sintered PDC or PCBN. Due to the great disparity in the CTEs between PDC and PCBN and CoCr, high tension is formed at the interface 1501 between these two materials as shown in figure 15. The tension that is formed is greater than the bonding energy between the two materials. When the voltage is greater than the bonding energy, a crack is formed at the highest stress point. The crack then propagates following the strict high stress region concentrated at the interface. With reference to figure 16, in this way, the CoCr 1601 substrate will separate from the PCD or PCBN 1602 that has been sintered around it, regardless of the interface shape.
[000198] Materials other than CoCr can be used as a mold release. These materials include those materials with high CTEs and, in particular, those that are not good carbide builders. These are, for example, Co, Ni, CoCr, CoFe, CoNi, Fe, steel, etc. Gradient layers and voltage modifiers
[000199] Gradient layers and voltage modifiers can be used in the manufacture of super hard constructions. Gradient layers can be used to achieve any of the following objectives: A. Improve the “sweep” of solvent metal into the outer layer of super hard material and control the amount of solvent metal introduced for sintering in the outer layer. B. Provide a “sweep” source to discharge impurities to deposit on the surface of the outer layer of super hard material and / or chemical combination / fixation with the refractory containment cans. C. Control the volume module of the various gradient layers and thereby control the general expansion of the construction during the sintering process. D. Affect the CTE of each of the various layers by changing the ratio of metal or carbides to diamond, PCBN or other super hard materials to reduce the CTE of an individual gradient layer. E. Enable control of structural stress fields through the various levels of gradient layers to optimize the overall construction. F. Changing the direction of stress tensors to improve the outer super hard layer, for example, orienting the tensor vectors towards the center of a spherical construction to place the outer layer diamond in compression, or conversely, orienting the stress vectors tensioner from the center of the construction to reduce interface stresses between the various gradient layers. G. Improve the conformity of structural stress to external or internal loads by providing a construction that has substantially reduced fragility and increased toughness in which loads are transferred through the construction without crack initiation and propagation.
[000200] With reference to figure 17, the liquid sintering phase of PDC and PCBN is typically accomplished by mixing the solvent sintering metal 1701 directly with the PCBN 17 02 diamond or powders prior to HPHT compression, or (referring to the figure 18) “sweeping” the solvent metal 1802 from a substrate 1801 into input powders from the adjacent substrate during HPHT. High quality PDC or PCBN is created using the “sweep” process.
[000201] There are several theories related to the increased quality of PDC and PCBN when using the scanning method. However, most of those familiar with the field agree that allowing the sintering metal to "sweep" the substrate material provides a "wavefront" of sintering metal that quickly "moistens" and dissolves the diamond or CBN and uses only as much metal as required to precipitate diamond or particle bond with PCBN particle. Whereas in a "pre-mixed" environment the metal "blocks" the particle to particle reaction because too much metal is present, or conversely, not enough metal is present to ensure the optimal reaction.
[000202] Furthermore, it is felt that the "wavefront" of sweeping metal through the powder matrix also takes away impurities that would otherwise prevent the formation of high quality PDC or PCBN. These impurities are normally "pushed" in front of the sintering metal "wavefront" and are deposited in pools adjacent to the refractory containment cans. Figure 19 represents the substrate 1904, the 1903 wavefront, and the 1902 crystals or powder that the wavefront will sweep through 1901. Certain refractory material such as Niobium, molybdenum and zirconium can act as “metal absorbers” that combine with impurities that immerse from the matrix providing additional assistance in creating high quality end products.
[000203] Although there are compelling reasons to use the “scanning” process in the sintering of PDC and PCBN there are also problems that arise from its use. For example, not all substrate metals are as controllable as others with respect to the amount of material that is distributed and finally used by the powder matrix during sintering. cobalt metal (6 to 13% by volume) sweeping of cemented tungsten carbide is very controllable when used against diamond or PCBN powders ranging in size from 1 to 40 microns of particle. On the other hand, molybdenum chromium cobalt (CoCrMo) which is useful as a solvent metal for making PDC for some applications outperforms the same PDC matrix with CoCrMo metal in a pure scanning process sometimes producing inferior quality PDC. The fact that CoCrMo has a lower melting point than cobalt and additionally that there is an inexhaustible source when using a solid CoCrMo substrate adjacent to the PDC matrix, creates an uncontrollable processing condition.
[000204] In some applications where it is necessary to use sintering metals such as CoCrMo that cannot be “wiped off” from a cemented carbide product, it is necessary to provide a substrate simulated against PDC powders that provide a controlled release and limited supply of CoCrMo for the process.
[000205] These “simulated” substrates were developed in the form of “gradient” layers of mixtures of diamonds, carbides, and metals to produce the desired “sweep” effect to sinter the outer layer of PDC. The first “gradient layer” (immediately adjacent to the primary or external diamond layer that will act as the use or support surface) can be prepared using a mixture of diamond, Cr.sub.3C.sub.2 and CoCrMo. Depending on the fraction size of the diamond powder used in the outer layer, the diamond size fraction and metal content of the first gradient layers are adjusted for optimal sintering conditions.
[000206] Where a “simulated” substrate is used, it has been found that often a small amount of solvent metal, in this case CoCrMo must be added to the outer diamond layer as a catalyst to “correct” the sintering reaction.
[000207] One modality uses the mixing ranges for the external gradient 2001 and internal 2002 layers of figure 20 which are listed in table 9. Table 9

[000208] The use of gradient layers with solid layers of metal allows the designer to match the volume module with the CTE of various construction features to counteract expansion forces encountered during the HTHP phase of the sintering process. For example, in a spherical construction as the pressure increases the metals in the construction are compressed or expanded radially towards the center of the sphere. Conversely, as the sintering temperature increases, the metal expands radially away from the center of the sphere. Unless these forces are balanced in some way, the compressive expansion forces will initiate cracks in the outer diamond layer and make the construction unusable.
[000209] Typically, changes in volume modulus of solid metal characteristics in construction are controlled by selecting metals with a compatible modulus of elasticity. Thickness and other design characteristics are also important. CTE, on the other hand, is altered by adding diamond or other carbides to the gradient layers.
[000210] One modality, represented in figure 21, involves the use of two outer layers of gradient 2101 and 2102, a layer of solid titanium 2104 and an inner CoCrMo sphere 2103. in this modality the first gradient layer provides a “scanning source ”Of biocompatible CoCrMo solvent metal for the outer diamond layer. The solid titanium layer provides an expansion source that displaces the CTE from the central sphere of solid CoCrMo and prevents it from "pulling away" from the titanium / CoCrMo interface as the sintering pressure and temperature goes from 65 Kbar and 1400 degrees C sintering range for 1 bar and room temperature.
[000211] Where two or more powder-based gradient layers are to be used in construction it becomes increasingly important to control the CTE of each layer to ensure structural integrity after sintering. During the sintering process, stresses are induced along the interface between each of the gradient layers. These high stresses are a different result of the differences in CTE between any two adjacent layers. To reduce these stresses, the CTE of one or both layer materials must be modified.
[000212] The CTE of a substrate can be modified by changing to a substrate with a CTE close to that of diamond (an example is the use of cemented tungsten carbide, where the diamond CTE is approximately 1.8 mu.m / m grade.C and cemented tungsten carbide is approximately 4.4 mu.m / m-grade.C), or in the case of powdered layers, by adding a low CTE material to the substrate layer itself. That is, making a mixture of two or more materials, one or more of which will alter the CTE of the substrate layer.
[000213] Metal powders can be mixed with diamond or other super hard materials to produce a material with a CTE close to that of diamond and thus produce stresses low enough after sintering to prevent slipping of the layers at their interfaces. Experimental data show that materials that alter CTE generically will not react with each other, which allows the researcher to predict the result of the intermediate CTE for each gradient level.
[000214] The desired CTE is obtained by mixing specific quantities of two materials according to the mixing rule. Table 10 shows the change in CTE between two materials, A and B as a function of composition (percentage of volume). in this example, materials A and B have CTEs of 150 and 600 mu.In/In.-grau.F respectively. By adding 50 mol% of A to 50 mol% of B the resulting CTE is 375 mu.in/in.grau F.
[000215] One or more of the following component processes is incorporated into the mold release system: 1. An intermediate layer of material between the PDC part and the mold that prevents binding of the polycrystalline diamond compact to the mold surface. 2. A mold material that does not bond to the PDC under the conditions of synthesis. 3. A mold material that, in the final stages of or at the completion of, the PDC synthesis cycle contracts away from the PDC in the case of a liquid concave PDC geometry, or expands away from the PDC in the case of a PDC geometry liquid convex. 4. The mold shape can also simultaneously act as a scanning metal source useful in the PDC synthesis process.
[000216] As an example, a mold release system can be used in the manufacture of a PDC by employing a negative shape of the desired geometry to produce non-flat parts. The mold surface contracts away from the final liquid concave geometry, the mold surface acts as a source of catalyst-solvent metal for the PDC synthesis process, and the mold surface has poor binding properties for PDCs. Table 10 - dimensional changes predicted in a 0.2 m (eight inch) layered construction.

[000217] Figure 22 is an illustration of how the above CTE modification works in a one-dimensional example. The one-dimensional example also works on a three-dimensional construction. If materials A and B above are packed in alternating layers 2201 and 2202 as shown in figure 22, separately in their pure forms, with their CTEs of 150 and 600 .mu.In / in.grau F, respectively, they will contract exactly 150 mu /in/in.grau.F and 600 mu.in/in.grau F for any decrease in degrees in temperature. For a block of 0.2m (eight inches) of stacked layers with a thickness of 0.0254m (one inch) the total change in dimension for a decrease of one degree in temperature will be: Material A: (4 times 1 in.) Times (0.00015 in / in. Degree F) times 1 degree F = 0.015 mm (0.0006 in). Material B: (4 times 1 in.) Times (0.00060 in / in. Degree F) times 1) degree F = 0.06 mm (0.024 in). Total decrease in overall length by 0.20 m (eight inches) = 0.0762mm (0.030 in).
[000218] By comparison, each of the layers is modified using a mixture of 50% A and 50% B, and all eight layers are stacked in the 0.20 m (eight inch) block configuration. The recalculation of the overall length decrease using the new 375 mu.In./in F grade CTE composite from table II shows: Material A + B (8 times. 1 in.) Times (0.000375 in./in degree F) times 1 degree F = 0.0762 mm (0.0030 in). Total decrease in overall length by 0.2032m (eight inches) = 0.0762 mm (0.0030 in).
[000219] The decrease in length in this case was predicted precisely for the one-dimensional construction using layers with an inch of thickness using the mixing rule.
[000220] Metals have very high CTE values compared to diamond, which has one of the lowest CTEs of any known material. When metals are used as substrates for sintering PCBN and PDC considerable tension is developed at the interface. Therefore, a mixture of low CTE material with biocompatible metal for medical implants can be used to reduce interfacial stresses. One of the best candidate materials is the diamond itself. Other materials include refractory metal carbides and nitrides and some oxides. Borides and silicides would also be good materials from a theoretical point of view, but they may not be bicompatible. The following is a list of candidate materials: carbides, silicides, oxynitrides, nitrides, oxides, oxiborides, borides, oxycarbides, carbonitrides.
[000221] There are other materials and material combinations that could be used as CTE modifiers.
[000222] There are also other factors that apply to the reduction of interface stresses for a specific geometric construction. The thickness of the gradient layer, its position in the construction, and the overall shape of the final construction all contribute to the reduction of the interfacial stress tensor. Geometries that are more spherical tend to promote circumferential interface failures from positive or negative radial tensors while geometries of a cylindrical configuration tend to fail at layer interfaces precipitated by flexing stress pairs.
[000223] The design of the gradient layers in relation to the CTE and the amount of contraction that each individual layer will experience during cooling form the HTHP sintering process will largely determine the direction of stress tensors in the construction. Generally, the designer always wants to have the external use layer of super hard material in compression to avoid slipping and crack propagation. In spherical geometries the stress tensors would be directed radially towards the center of the spherical shape paying special attention to interfacial stresses at each layer interface to avoid failures in those interfaces as well. In cylindrical geometries the stress tensioners would be adjusted to prevent stress pairs from starting cracks at any end of the cylinder, especially at the end where the use surface is present.
[000224] Following are modalities that refer to a spherical geometry where combinations of gradient layers and / or solid metal spheres are used to control the final results of the constructions. Figure 23 is a modality that shows a spherical construction, which uses five gradient layers in which the composition of each layer is described in tables 11 and 12: Table 11

Table 12

[000225] Figure 24 is a modality that shows a spherical construction, which uses four gradient layers in which the composition of each layer is described in tables 13 and 14. Table 13
Table 14

[000226] Figure 25 shows a modality construction that uses a central support sphere with gradient layers arranged in the sphere and with each other to form the complete construction. The CoCrMo solid metal inner sphere is encapsulated with a 0.0462mm to 0.254mm (0.003 to 0.010 inch) refractory barrier can 2504 thick to prevent over-saturation of the system with the sphere metal during the HTHP sintering phase . The composition of each layer is described in tables 15 and 16. Table 15
Table 16

[000227] Provided for the end use function of the above sphere, the inner sphere can be made of cemented tungsten carbide, niobium, nickel, stainless steel, steel or one of several other ceramic or metal materials to suit the needs of the designer.
[000228] The modalities referring to dome formats are described as follows:
[000229] Figure 26 shows a dome modality construction that uses two gradient layers 2601 and 2 602 in which the composition of each layer is described in tables 17 and 18. Table 17
Table 18


[000230] Figure 27 shows a dome modality construction that uses two gradient layers 2701 and 2 7 02 in which the composition of each layer is described in tables 19 and 20: Table 19
Table 20

[000231] Figure 28 shows a dome modality construction that uses three gradient layers 2801, 2802 and 2803 where the composition of each layer is described in tables 21 and 22: Table 21
Table 22

[000232] Figure 29 shows a dome modality construction that uses three gradient layers 2901, 2902 and 9803 in which the composition of each layer is described in tables 23 and 24. Table 23
Table 24

[000233] The modalities related to flat cylindrical formats are described as follows:
[000234] Figure 30 shows a flat cylindrical construction using two gradient layers 3001 and 3002 in which the composition of each layer is described in tables 25 and 26. Table 25
Table 26

[000235] Figure 31 shows a flat cylindrical construction that uses three gradient layers 3101, 3102, 3103 in which the composition of each layer is described in tables 27 and 28: Table 27
Table 28

[000236] Figure 32 shows a flat cylindrical construction using three gradient layers 3201, 3202, 3203 arranged on a CoCrMo 3204 substrate. The CoCrMo 3204 solid metal cylindrical substrate is encapsulated with a refractory barrier can with 0, 0762 to 0.254 mm (0.003 to 0.010 inch) 3205 thick to avoid over-saturation of the system with the substrate metal during the HTHP sintering phase. The composition of each layer is described in tables 29 and 30: Table 29
Table 30

[000237] Foreseen in the end use function of the cylinder shape of figure 32 the internal substrate could be made of cemented tungsten carbide, niobium, nickel, stainless steel, steel, or one of several other ceramic or metal materials to suit meet the needs of the designer.
[000238] The preferred modalities for flat cylindrical shapes with concave characteristics formed in place are described as follows:
[000239] Figure 33 shows a modality of a flat cylindrical shape with a load support or concave chute formed in place 3303 that uses two gradient layers 3301 and 3302 in which the composition of each layer is described in tables 31 and 32: Table 31
Table 32

[000240] Figure 34 shows a modality of a flat cylindrical shape with a load support or concave gutter formed in place 3403 that uses two gradient layers 3401 and 3402 in which the composition of each layer is described in tables 33 and 34. Table 33
Table 34

[000241] Figure 35 shows a modality of a flat cylindrical shape with a load support or concave chute formed in place 3504 that uses three gradient layers 3501, 3502, 3503 in which the composition of each layer is described in tables 35 and 36: Table 35

Table 36

[000242] Figure 36 shows a modality of a flat cylindrical shape with a load support or concave chute formed in place 3604 that uses three gradient layers 3601, 3602, 3603 in which the composition of each layer is described in tables 37 and 38: Table 37

Table 38
Prepare heater assembly
[000243] To sinter the loaded and assembled diamond input described above in PCD, both heat and pressure are required. Heat is supplied electrically as the part is subjected to pressure in a press. A heater assembly is used to provide the necessary heat.
[000244] A refractory metal can containing pre-compressed and loaded diamond input is placed in a heater assembly. Salt domes are used to close the can. The salt domes used can be white salt (NaCl) which is pre-compressed to at least approximately 90-95% of theoretical density. This salt density is desirable to preserve high pressures of the sintering system and to maintain the geometric stability of the manufactured part. The salt and can domes are placed in a graphite heater tube assembly. The graphite and salt components of the heater assembly can be cooked in a vacuum oven greater than 100 degrees Celsius and in a vacuum of at least 23 torr for approximately 1 hour to eliminate absorbed water before loading into the heater assembly. Other materials that can be used in the construction of a heater assembly include sheet or solid graphite, amorphous carbon, pyrolytic carbon, refractory metals and high electrical resistant metals.
[000245] After electrical energy is supplied to the heating tube, it will generate the heat required to form a polycrystalline diamond in the high temperature / high pressure compression operation. Preparation of pressure assembly for sintering
[000246] After a heater assembly has been prepared, it is placed in a pressure assembly for sintering in a press under high temperature and high pressure. A cubic press or a belt press can be used for this purpose, with the pressure assembly differing somewhat depending on the type of press used. The pressure assembly is designed to receive pressure from a press and transfer it to the diamond input so that diamond sintering can take place under isostatic conditions.
[000247] If a cubic press is used, then a cube of pressure transfer medium suitable as pyrophyllite will contain the heater assembly. Cell pressure medium can be used if sintering is to occur in a belt press. Salt can be used as a means of transferring pressure between the hub and the heater assembly. Thermocouples can be used in the cube to monitor temperature during sintering. The hub with the heater assembly inside it is considered a pressure assembly, and is placed in a sintering press. Input sintering in PCD
[000248] The pressure assembly described above containing a refractory metal can that has a pre-compressed and loaded diamond input in it is placed in an appropriate press. A suitable press is used to create high temperature and high pressure conditions for sintering.
[000249] To prepare for sintering, the entire pressure assembly is loaded into a cubic press and initially pressurized to approximately 40-68 Kbars. The pressure to be used depends on the product to be manufactured and must be determined empirically. Then electrical energy is added to the pressure assembly to reach a temperature in the range of less than approximately 1145 or 1200 to more than approximately 1500 degrees Celsius. Approximately 5800 watts of electrical power is available on the two opposite anvil faces, creating the current flow required for the heater assembly to generate the desired level of heat. After the desired temperature is reached, the pressure assembly is subjected to a pressure of approximately 6894.76 MPa (1 million pounds per square inch) on the anvil face. The components of the pressure assembly transmit pressure to the diamond input. These conditions are maintained for approximately 3-12 minutes, but could be less than 1 minute to more than 30 minutes. the sintering of PDCs occurs in an isostatic environment where the pressure transfer components are only allowed to change in volume but are not allowed to otherwise deform. After finishing the sintering cycle, a period of approximately 90 seconds of cooling is allowed, and then pressure is removed. The PDC is then removed for finishing.
[000250] The removal of a sintered PDC having a curved, compound or complex shape from a pressure assembly is simple due to the differences in material properties between diamond and the surrounding metals in some modalities. This is generally referred to as a mold release system. PCD-solvent catalyst metal removal
[000251] If desired, the catalyst-solvent metal that remains in the interstitial spaces of the sintered PCD can be removed. Such removal is accomplished by chemical bleach as known in the synthetic diamond field. After the catalyst-solvent metal has been removed from the interstitial spaces in the diamond table, the diamond table will have greater stability at elevated temperatures. This is because there is no catalyst for the diamond to react and break.
[000252] After leaching the catalyst-solvent metal from the diamond table, it can be replaced with another metal or metal compound to form a thermally stable diamond that is stronger than leached PCD. If it is intended to weld synthetic diamond or a PDC to a substrate or other surface as by inertial welding, it may be desirable to use a thermally stable diamond due to its heat resistance generated by the welding process. Manufacture of concave surfaces
[000253] An example substrate geometry for making a spherical, hemispherical or partially spherical concave polycrystalline diamond compact can be understood in combination with the examination of figures 37A-37C. the substrate 601 (e 601a and 601b) can be in the form of a cylinder with a hemispherical receptacle 602 e (602a and 602b) formed at one of its ends. Two substrate cylinders 601a and 601b are placed so that their hemispherical receptacles 602a and 602b are adjacent to each other, thereby forming a spherical cavity 604 between them. A sphere 603 of a suitable substrate material is located in cavity 604. Diamond input 605 is located in cavity 604 between the outside of sphere 603 and the concave surfaces of receptacles 602a and 602b of substrate cylinders 601a and 601b. the assembly is placed in a 610 refractory metal can for sintering. The can has a first cylinder 610a and a second cylinder 601b. the two cylinders join in a ferrule 611. After such an assembly is sintered, the assembly can be split, cut or ground along the center line 606 to form a first cup assembly 607a and a second cup assembly 607b. sample substrate materials for cylinders 602a and 602b are CoCrMo (ASTM F-799) and CoCrW (ASTM F-90) and an example substrate material for sphere 603 is CoCrMo (ASTM F-799) although any material appropriate substrate can be used, including some of those listed elsewhere here. Manufacture of convex surfaces
[000254] In this section, examples for making various convex super hard surfaces are provided. Referring to Figures 13A-13F, various substrate structures of the invention for making a generally spherical or compact polycrystalline polycrystalline boron nitride diamond are shown. Figures 13A and 13B represent two-layer substrates.
[000255] In figure 13A, a first solid sphere 501 of a substrate material intended for use as the substrate wrapper or outer layer was obtained. The dimensions of the first sphere 501 are such that the dimension of the first sphere 501 with a diamond table on its exterior will approximate the desired dimension of the component before final finishing. After the first sphere 501 of the substrate is obtained, a hole 502 is drilled in its center. Hole 502 is preferably drilled, drilled, cut, blown or otherwise formed so that the end 503 of hole 502 is hemispherical. This can be achieved using a drill or end mill with a ball or round end having the desired radius and curvature. Next, a second sphere 504 of a substrate material is obtained. The second ball 504 is smaller than the first ball 501 and must be placed in bore 502 in the first ball 501. The ball substrate materials 501 and 504 can be selected from those listed in the tables above. They can also be made of other suitable materials. The second ball 504 and the hole 502 and its end 503 must fit together closely without excessive tolerance or play. A plug 505 that can be of the same substrate material as the first sphere 501 is formed or obtained. Plug 505 has a first end 505a and a second end 505b and substrate material between them to fill hole 502 except for that portion of hole 502 occupied by the second sphere 504 adjacent to hole end 503. Plug 505 can have a concave hemispherical receptacle 506 at its first end 505a so that plug 505 will abut closely on second ball 504 through approximately half the spherical surface of second ball 504. Plug 505 may be generally cylindrical in shape. The substrate assembly including a substrate sphere placed inside another can then be loaded with 507 diamond input or cubic boron nitride input and sintered under high pressure and high temperature to form a spherical polycrystalline diamond compact.
[000256] With reference to figure 13B, another substrate geometry for making spherical polycrystalline diamond or cubic boron nitride compacts is represented. An inner core 550 sphere of appropriate substrate material is selected. Next, a first external substrate hemispherical, 551, and a second external substrate hemispheric 552, are selected. Each of the first and second outer substrate hemispheres 551 and 552 are formed so that each has a hemispherical receptacle 551a and 552a shaped and sized to accommodate the placement of the hemispheres around the outside of the inner core sphere 550 and thereby encase and encapsulate the inner core sphere 550. Inner core sphere substrate materials 550 and hemispheres 551 and 552 are preferably selected from those listed in the tables above or other appropriate materials. With the hemispheres and inner core ball assembled, the 553 diamond input can be loaded onto the outside of the hemispheres and sintering of high temperature and high pressure can proceed to form a spherical compact.
[000257] Although figures 13A and 13B represent two-layer substrates, it is possible to use multi-layer substrates (3 or more layers) for the manufacture of polycrystalline diamond or polycrystalline diamond compacts or polycrystalline cubic boron nitride compacts. The selection of a substrate material, substrate geometry, topographic characteristics of substrate surface, and substrates having a plurality of layers (2 or more layers) of the same or different materials depends at least in part on the thermomechanical properties of the substrate, baro properties -mechanics of the substrate, and baro-mechanical properties of the substrate.
[000258] With reference to figure 13C, another substrate configuration for making generically spherical compacts is represented. The substrate 520 has the general shape of a sphere. The surface of the sphere includes substrate surface topography designed to increase attachment of a diamond table to the substrate. The substrate has a plurality of depressions 521 formed on its surface. Each depression 521 is formed as three different levels of depression 521a, 521b and 521c. the depressions are represented as concentric circles, each with approximately the same depth, but their depths may vary, the circles do not need to be concentric, and the shape of the depressions does not need to be circular. The depression walls 521d, 521e and 521f are represented as being parallel to a radial geometric axis of the depressions whose geometric axis is perpendicular to a tangent to the theoretical spherical end of the sphere, but could have a different orientation if desired. As shown, the surface of the substrate sphere 522 does not have topographic characteristics different from the depressions already mentioned, however it could have protrusions, depressions or other modifications as desired. The width and depth dimensions of the 521 depressions may vary according to the polycrystalline diamond compact being manufactured. The diamond input can be loaded against the exterior of the substrate sphere 520 and the combination can be sintered at stable diamond pressures to produce a spherical polycrystalline diamond compact. The use of topographic characteristics of substrate surface on a generally spherical substrate provides a superior link between the diamond table and the substrate as described above and allows a polycrystalline diamond compact to be manufactured using a single layer substrate. This is due to the grabbing action between the substrate and the diamond table obtained by using topographic characteristics of the substrate surface.
[000259] With reference to figure 13D, a spherical segmented substrate 523 is represented. The substrate has a plurality of surface depressions 524 equally spaced around its outer surface. These depressions as represented are formed at levels of three different depths. The first level 524a is formed at a predetermined depth and is pentagonal in shape around its outer periphery. The second level 524b is round in shape and is formed at a predetermined depth that may differ from the predetermined depth of the pentagon. The third level 524c is round in shape and is formed at a predetermined depth that may differ from each of the other depths mentioned above. Alternatively, the depressions can be formed only at a depth, they can all be pentagonal, or they can be a mixture of shapes. The depressions can be formed by machining the substrate sphere.
[000260] Referring to figure 13E, a cross section of an alternative substrate configuration for making a polycrystalline or cubic polycrystalline boron nitride compact is shown. A compact 525 is shown. The 525 compact is spherical. Compact 525 includes a diamond table 526 sintered with a substrate 527. The substrate is partially spherical in shape on its distal side 527a and is dome-shaped on its near side 527b. alternatively, the side 527b of the substrate 527 can be described as being partially spherical, but the sphere on which it is based has a smaller radius than the sphere on which the distal side 527a of the substrate is based. Each of the top 527c and the bottom 527d is formed in a convenient shape to transition from the partial substrate sphere of the near side 527b to the partial substrate sphere of the distal side 527a. this substrate configuration has advantages in that it leaves a portion of the substrate exposed for drilling and fixing fasteners without disturbing residual stress fields of the polycrystalline diamond table. It also provides a portion of the substrate that has no sintered diamond in it, allowing expansion of the substrate during sintering without breaking the diamond table. More than 180 degrees from the outside of the substrate sphere has diamond in it, however, so that the part is useful as a femoral head or other articulation surface.
[000261] With reference to figure 13F, a cross section of an alternative substrate configuration for making a polycrystalline diamond compact is shown. A polycrystalline diamond compact 528 is depicted having a diamond table 529 and a substrate 530. The substrate has topographic characteristics 531 to increase resistance of the diamond interface to substrate. Topographic features may include rectangular protrusions 532 separated by depressions 533 or corridors. The distal side of the substrate is formed on the basis of a sphere of radius r. the side close to the substrate 530b is formed based on a sphere of radius r ', where r> r'. normally the surface changes will be found under substantially the entire diamond table.
[000262] Referring to figure 13G, another generally spherical compact 535 is shown which includes a diamond table 536 sintered with a substrate 536. The substrate is configured as a sphere with a protruding cylindrical shape. The head 535 is formed so that a quantity of substrate protrudes from the spherical shape of the head to form a neck 538 that can be attached to an appropriate body by any known fixation method. The use of a preformed neck 538 on the substrate that is used to make a polycrystalline diamond or cubic boron nitride compact 535 provides a fixing point on the polycrystalline diamond compact that can be used without disturbing the residual stress field of the compact . The neck 538 shown is an integral component of a stem 540.
[000263] Any of the aforementioned substrate configurations and substrate topographies and variations and derivatives thereof can be used to manufacture a polycrystalline or cubic polycrystalline boron nitride compact for use in a variety of fields. In several embodiments, a single layer substrate can be used. In other embodiments, a two-layer substrate can be used, as discussed. Depending on the properties of the components being used, however, it may be desired to use a substrate that included three, four or more layers. Continuous and segmented super hard structures
[000264] In this section, the concept of structures using segments of hard or super hard materials is discussed. The segments (or inserts) can have a concave, convex or flat contact area, as desired, and can simplify the construction of products with complex geometries. Structures with segmented super hard surfaces can be made by sintering the super hard segments in place on a substrate so that the super hard material segments and the substrate form an integral super hard compact. Or structures with segmented hard or super hard surfaces can be made by fabricating the super hard or hard material in advance, and then installing it on a separate substrate later by such techniques as friction fitting, interference fitting, mechanical locking, brazing, welding, adhesion, etc. for comparison, super-hard structures with continuous surfaces are also discussed below. example continuous and segmented structures are discussed now.
[000265] The geometry in figures 4A-B consists of veins or lists of supporting material that start from a polar region and migrate outward with a slight angular propensity. Figure 4A shows a side view of the head 4A-101. Specifically, the substrate material 4A-104 is marked by raised diamond ridges 4A-102 and recessed rails 4A-103 between the diamond ridges 4A-102. Figure 4B is a top view of figure 4A illustrating a pattern of arched ridges emanating from a central location or spherical point. A straight-line version of this pattern is also possible.
[000266] The geometry of figures 4C-4D consists of wavy lines that are continuous around the surface of the sphere. Figure 4C illustrates a side view of the head with a spherical point 4C-101 such that elevated non-linear diamond ridges 4C-103 surround the substrate material 4C-102. Like figures 4A and 4B, gutters 4C-104 exist between diamond ridges 4C-103. Figure 4D is a top view of figure 4C. a straight-line version of this pattern is also possible.
[000267] Materials for inserts include, but are not limited to, diamond, cubic boron nitride, corbonitride steels, steel, carbonitrides, borides, nitrides, silicides, carbides, ceramic matrix composites, fiber-reinforced ceramic matrix composites, cast iron, alloy and carbon steels, stainless steel, bearing bearing steel, tool steel, hard face alloys, cobalt based alloys, Ni3Al alloys, surface treated titanium alloys, cemented carbides, cermets, ceramics, materials based on carbon graphite, fiber reinforced thermoplastics, metal matrix composites.
[000268] Materials for the substrate include, but are not limited to, corbonitride steels, steel, carbonitrides, borides, nitrides, silicides, carbides, ceramic matrix composites, fiber reinforced ceramic matrix composites, cast iron, alloy steels and carbon, stainless steel, bearing bearing steel, tool steel, hard face alloys, cobalt based alloys, Ni3Al alloys, surface treated titanium alloys, cemented carbides, cermets, ceramics, carbon graphite based materials, fiber reinforced thermoplastics, metal matrix composites.
[000269] The substrate can be configured in order to place the insertion material in a compressive state sufficient to transmit structural stability to the insertion material that until now was not present. The insertion material is placed in a compressive state by using an interference fit with the surrounding substrate material. By placing the insertion material in this compressive condition the neutral tension geometric axis in the insertion material is displaced in such a way that the support material is now able to support a higher load while maintaining its structural integrity in combination with its superior usage properties . This allows the use of materials that have very desirable usage properties but insufficient structural capacity to now be configured in such a way as to make them the same candidates for wear bearings that until now were not available for use. The substrate material can be machined or cast with the desired geometry for the backing material. The substrate material is then heated to a predetermined temperature and the wear bearing inserts are cooled to a predetermined temperature and then the wear bearing insert is pressed into the substrate. The difference in material size results in the wear bearing material being in a compressive state.
[000270] Figures 4E and 4E-1 represent a 4E109 spherical structure with a continuous super hard surface. The 4E109 structure depicted can be a polycrystalline diamond compact that includes a volume of 4E9 diamond surface on a 4E10 substrate. This modality includes a continuous surface diamond layer, although the diamond surface can be discontinuous as well.
[000271] Figures 4F and 4F1 represent a segmented sphere 4F110 with super hard inserts 4F11 on the 4F12 surface to form a discontinuous super hard surface. The 4F11 inserts can be located on the substrate material with great precision and accuracy. The surface of the sphere can be divided into areas of diamond or other super hard material separated by veins of substrate material. The manufacture of spheres with this vein and patch structure (such as a segmented round or polyhedral surface) offers some advantages for the manufacturing process for certain substrate metals as well as providing some advantages in high impact situations. Each supporting diamond segment or super hard material independently accommodates transient deformations under peak load without resulting in fracture of the diamond segments or super hard material.
[000272] Figures 4G and 4G1 represent a cross-sectional view of a 4G111 sphere with 4G 14 plugs. 4G plugs 14 can be a compact polycrystalline diamond having a polycrystalline diamond surface or other super hard material. The 4G14 plugs can be securely attached to receptacles on the 4G 15 spherical substrate sphere or other desired structure, or they can be formed as a compact with the substrate. The plugs or segments can be shaped as compact polycrystalline diamonds or other super hard material. Each plug can be a continuous phase of super hard material, or a compact formed from a supporting surface of super hard material on a substrate, such as a polycrystalline diamond compact. The plugs can be bonded, welded or mechanically attached to the substrate structure, preferably in a suitable receptacle, leaving a super hard support surface exposed. High quality spherical and curvilinear surface finishes that are obtained by terminal finishing processes described later in this document. This approach to segmented support surfaces allows the manufacture of extremely large and / or curvilinear spherical support surfaces not possible with continuous support surfaces. Size limitations in the manufacture of compact polycrystalline diamond elements could otherwise prevent the manufacture of such large elements.
[000273] Figures 4H and 4H1 represent a 4H112 sphere made of solid or continuous polycrystalline diamond or other super hard material. This 4H112 sphere is made of super hard material or solid diamond without a separate substrate. The 4H112 sphere has a continuous diamond phase throughout. The modalities of such a continuous phase support element can be made of polycrystalline diamond, polycrystalline cubic boron nitride, or other super hard material. This structure has certain advantages from a structural and electromagnetic chemical point of view.
[000274] Figures 4I and 4I1 represent a 4I113 sphere with strips, veins or a 4I17 discontinuous diamond pattern or other super hard material located on a 4I18 substrate. The diamond on the surface of the 4I13 sphere can be in a regular or irregular discontinuous pattern in any desired geometry, such as concentric circles, spirals, latitudinal or longitudinal lines or otherwise. This structure has some of the advantages common to the segmented support surface described above. Finishing devices and methods
[000275] After a PDC has been sintered, a mechanical finishing process can be employed to prepare the final product. The finishing steps explained below are described with respect to finishing a PDC, however they could be used to finish any other surface or any other type of component.
[000276] The synthetic diamond industry faced the problem of finishing flat surfaces and thin edges of diamond compacts. Methods for removing large amounts of diamond from non-flat surfaces or finishing those surfaces to a high degree of precision for sphericity, size and surface finish had not been developed in the prior art. Finishing flat and cylindrical super hard shapes
[000277] To provide a greater perspective on finishing techniques for super hard curved and non-flat surfaces for modular support inserts and joints, a description of other finishing techniques is provided. Lapidary
[000278] A wet diamond sand grain paste on rotating copper or cast iron plates is used to remove material on larger flat surfaces (for example, up to approximately 70 mm in diameter). End-coated cylinders ranging in size from approximately 3 mm to approximately 70 mm can also be ground to create flat surfaces. Grinding is generally slow and non-dimensionally controllable for depth and layer thickness, although surface and smooth finishes can be retained in very narrow tolerances. Grinding
[000279] Diamond-impregnated grinding wheels are used to shape flat, cylindrical surfaces. Grinding wheels are usually bonded by resin in a variety of different shapes depending on the type of material removal required (ie, edge grinding or grinding without a cylindrical center). PDCs are difficult to grind, and large PDC surfaces are almost impossible to grind. Consequently, it is desirable to keep grinding to a minimum, and grinding is usually confined to a narrow perimeter or edge or to the sharpening of a machine tool or coated cylinder insert at the dimensioned PDC end. Electro-spark discharge (EDG) grinding
[000280] PDC rough machining can be carried out with electroparticular discharge grinding (“EDG”) on large diameter flat surfaces (for example, up to approximately 70 mm). This technology typically involves the use of a rotating carbon wheel with a positive electrical current passing against a flat surface of PDC with a negative electrical potential. The automatic controls of the EDG machine maintain adequate electrical erosion of the PDC material by controlling variables such as spark frequency, voltage and others. EDG is typically a more efficient method for removing larger volumes of diamond than grinding or grinding. After EDG, the surface must be ground or polished to remove what is referred to as the heat-affected area or molten layer left behind by EDG. Electric wire discharge machining (WEDM)
[000281] WEDM is used to cut super hard parts of various shapes and sizes from larger cylinders or flat parts. Typically, cutting tips and inserts for machine tools and remoulding cutters for oil well drilling bits represent the greatest use for WEDM in PDC finishing. Polishing
[000282] Polishing of super hard surfaces for modular support inserts and joints at very high tolerances can be carried out by high speed polishing machines impregnated with diamond. The combination of high friction temperatures and high pressure tends to burnish a PDC surface finished by this method, while maintaining high degrees of flatness, thereby producing a mirror-like appearance with precise dimensioned accuracy. Finishing a non-flat geometry
[000283] Finishing a non-flat surface (non-flat concave or non-flat convex) presents a greater problem than finishing a flat surface or the rounded edge of a cylinder. The total surface area of a sphere to be finished compared to the total surface area of a round end of a cylinder of similar radius is four (4) times greater, resulting in the need to remove four (4) times the amount of material from PDC. The nature of a non-flat surface makes traditional processing techniques such as grinding, grinding and others unusable because they are adapted for cylindrical and flat surfaces. The point of contact on a sphere should be a point of contact that is tangential to the edge of the sphere, resulting in a lesser amount of material removed per unit time, and a proportional increase in required finishing time. In addition, the design and types of processing equipment and tools required for finishing non-flat objects must be more accurate and must operate at closer tolerances than those for other formats. Non-flat finishing equipment also requires greater degrees of adjustment to position the workpiece and tool inlet and outlet.
[000284] Here are steps that can be taken to finish a non-flat, rounded or arched surface. 1.) Rough machining
[000285] Initially thinning the surface dimensions using a specialized electrical discharge machining device can be performed. Figure 38 represents roughing a PDC ball 3803. A rotator 3802 is provided which is continuously rotatable about its longitudinal geometric axis (the z geometric axis shown). The ball 3803 to be ground is fixed to a rotator shaft 3802. An electrode 3801 is provided with a contact end 3801a which is molded to accommodate the part to be ground. In this case, the contact end 3801a has a partially non-flat shape. The 3801 electrode is rotated continuously around its longitudinal geometric axis (the represented y axis). The angular orientation of the longitudinal geometric axis y of electrode 3801 with respect to the longitudinal geometric axis z of rotator 3802 at a desired angle .beta. is adjusted to cause electrode 3801 to remove material from the inner non-flat surface of ball 3803 as desired.
[000286] In this way, electrode 3801 and sphere 3803 are rotating around different geometrical axes. The adjustment of the geometrical axes can be used to obtain almost perfect non-plane movement of the part to be roughed. consequently, an almost perfect non-flat part results from this process. This method produces non-flat PDEC surfaces with a high degree of sphericity and cut to very narrow tolerances. By controlling the amount of current introduced into the erosion process, the depth and amount of the heat-affected zone can be minimized. In the case of a PDC, the heat-affected zone can be maintained at approximately 3 to 5 microns deep and is easily removed by grinding and polishing with diamond-impregnated grinding and polishing wheels.
[000287] With reference to figure 39, roughing of a 3903 convex non-flat PDC as an acetabular cup is represented. A rotator 3902 is provided which is continuously rotatable about its longitudinal geometry axis (the z geometry axis shown). The 3903 part to be roughed is fixed to a rotator axis. An electrode 3901 is provided with a contact end 3901a which is shaped to accommodate the part to be ground. The 3901 electrode is continuously rotating around its longitudinal geometric axis (the represented y axis). The angular orientation of the longitudinal geometric axis y of electrode 3901 with respect to the longitudinal geometric axis z of rotator 3902 at a desired angle .beta. is adjusted to cause electrode 3901 to remove material from the entire non-flat surface of cup 3903 as desired.
[000288] In some embodiments, multiple electrodes from the electrode discharge machine will be used in succession to machine a part. A battery of electroplating machines can be used to accomplish this in the assembly line mode. Additional refinements to machining processes and devices are described below.
[000289] Complex positive or negative landforms (concave or convex) can be machined in PDC or PCBN parts. this is a standard electric discharge machining (EDM) CNC machining center and properly machined electrodes perform the desired shapes.
[000290] Figure 40 (side view) and figure 40a (extreme views) show an electrode 4001 with a convex shape 4002 machined at the active end of electrode 4001, and the base of electrode 4005. Figure 41 (cross section at 41 -41) and figure 41a show an electrode 4101 with a concave shape 4102 and base 4105. The opposite ends of the electrodes are provided with a clamping mechanism on the base 4105 appropriate for the specific EDM machine being used. There are a variety of electrode materials that can be used such as copper, copper tungsten, graphite and combinations of mixtures of metal and graphite. Materials best suited for machining PDC and PCBN are tungsten copper for roughing and pure graphite, or mixtures of tungsten copper graphite. Not all EDM machines are capable of machining PDC and PCBN. Only those equipped with capacitor discharge energy sources can generate spark intensities with enough energy to efficiently erode these materials.
[000291] The effective size of the machined relief shape is usually machined to a smaller size to allow for an appropriate spark gap for the burning / erosion process to occur. Each spark gap length determines a set of machining parameters that must be adjusted by the machine operator to ensure efficient electrical discharge erosion of the material to be removed. Typically, two to four electrodes are prepared with different spark gap allowances. For example, an electrode using a spark gap of 0.15mm (.006 in). It could be prepared for "roughing", and an "interim" electrode with a spark gap of 0.05mm (0.002 in.), And a "finishing" electrode in 0.01mm (0.0005 in). Spark off. In each case, the machining voltage (V), peak amperage (AP), pulse duration (P), reference frequency (RF), retraction duration (R), duration under cut (U) and servo voltage ( SV) must be established in the machine control system.
[000292] Figure 42 shows an EDM 4201 relief shape sinking operation on a PDC 4202 insertion part. Table 39 describes the settings for using a roughing copper tungsten electrode 4203 and a copper tungsten electrode. / graphite for finishing. The spark gap 4204 is also shown. TABLE 39

[000293] Those familiar with the EDM field will recognize that variations in the displayed parameters will be required based on the electrode configuration, desired electrode usage rates, and required surface finishes. Generally, higher machining rates, that is, higher values of "V" and "AP" produce higher rates of discharge erosion, but conversely, rougher surface finishes.
[000294] Obtaining very smooth and precise finishes also requires the use of an appropriate dielectric machining fluid. Synthetic hydrocarbons with satellite electrodes as disclosed in US patent no. 5,773,782, which is hereby incorporated as a reference, seems to assist in obtaining high quality surface finishes.
[000295] Figure 43 shows a modality in which an EDM electrode with single ball nose (spherical radius) 4301 is used to form a concave relief shape 4303 in a part of PDC or PCBN 4302. Electrode 4301 is dipped vertically in part 4302 and then moved laterally to make the rest of the desired shape. By programming an EDM electrode “cutting path” from the EDM machine's CNC system, an infinite variety of concave or convex shapes can be machined. Controlling the “dip” and “lateral” cross-section rate and using the correct EDM material will determine the quality of the size dimensions and surface finishes achieved. 2.) Polishing and finishing grinding.
[000296] After the non-flat surface (either concave or convex) has been rough machined as described above or by other methods, polishing and finishing grinding of a part may occur. Grinding is intended to remove the heat-affected zone in the PDC material left behind by electrodes.
[000297] In some types of devices, grinding uses a sand grain size ranging from 100 to 150 according to ANSI standard B74.1601971 and polishing uses a sand grain size ranging from 240 to 1500, although the size of grain of sand can be selected according to the preference of the user. The grinding wheel speed must be adjusted by the user to obtain a favorable material removal rate, depending on the size of the sand grain and the material being ground. A small amount of experimentation can be used to determine the appropriate grinding wheel speed. After the spherical surface (either concave or convex) has been rough machined as described above or by other methods, polishing and finishing grinding of a part may occur. Grinding is intended to remove the heat-affected zone in the PDC material left behind by electrodes. The use of the same rotational geometry as shown in figures 38 and 39 allows the sphericity of the part to be maintained while improving its surface finish characteristics.
[000298] With reference to figure 44, it can be seen that a rotator 4401 retains a part to be finished 4403, in this case a convex sphere, by the use of an axis. Rotator 4401 is rotated continuously around its longitudinal geometric axis (the z axis). a polishing or grinding wheel 4402 is rotated continuously around its longitudinal geometric axis (the x geometric axis). the 4403 movable part is contacted with the 4402 movable polishing or grinding wheel. The angular .beta orientation. of rotator 4401 with respect to the polishing or grinding wheel 4402 can be adjusted and oscillated to grind or polish the part (ball or socket) across its entire surface and maintain sphericity.
[000299] With reference to figure 45, it can be seen that a rotator 4501 retains a part to be finished 4503, in this case a non-flat convex cup, by the use of an axis. Rotator 4501 is rotated continuously around its longitudinal geometric axis (the z axis). a polishing or grinding wheel 4502 is provided which is continuously rotatable about its longitudinal geometric axis (the x geometric axis). the movable part 4503 is contacted with the movable polishing or grinding wheel 4502. The angular orientation f of the rotator 4501 with respect to the polishing or grinding wheel 4502 can be adjusted and oscillated if necessary to grind or polish the part through the non flat of its surface.
[000300] In one embodiment, grinding uses a grain size of sand ranging from 100 to 150 according to ANSI standard B74.16-1971 and polishing uses a grain size of sand ranging from 240 to 1500, although the size of grain of sand can be selected according to the preference of the user. The speed of the grinding route must be adjusted by the user to obtain a favorable material removal rate, depending on the size of the sand grain and the material being ground. A small amount of experimentation can be used to determine the appropriate grinding wheel speed.
[000301] As desired, a hollow diamond abrasive grid can be used to polish diamond or super hard surfaces. A hollow diamond abrasive grid includes a hollow tube with a diamond matrix of metal, ceramic and resin (polymer).
[000302] If a diamond surface is being polished, then the speed of the polishing wheel will be adjusted to cause an increase in temperature or heat build-up on the diamond surface. This heat build-up will cause diamond crystals to shine to create a low mirror-like and very smooth friction surface. The effective removal of material during diamond polishing is not as important as the removal of sub-micron-sized roughness on the surface by an action of high-temperature honing of diamond particles rubbing against each other. A surface speed of at least 1828 m per minute (6000 feet per minute) is generally required along with a high degree of pressure to perform a burnishing action. Surface speeds of 1219 to 3048 m per minute (4000 to 10,000 feet per minute) are believed to be the most desirable range. depending on the pressure applied to the diamond being polished, polishing can be performed at approximately 152.4 linear meters per minute (500 linear feet per minute) and 6096 linear meters per minute (20,000 linear feet per minute).
[000303] Pressure must be applied to the workpiece to raise the temperature of the part being polished and thereby obtain the most desirable mirror-like polish, however the temperature should not be increased to the point where it causes complete degradation of the resin bond which holds the diamond polishing wheel matrix together, or resin will be deposited on the diamond. Excessive heat will also unnecessarily degrade the diamond's surface.
[000304] Maintaining a constant flow of refrigerant (such as water) through the diamond surface being polished, maintaining an appropriate wheel speed such as 1828 linear meters per minute (6000 linear feet per minute), applying sufficient pressure against the diamond to cause heat build-up, but not so much as to degrade the wheel or damage the diamond, and setting the polishing appropriately are all important and should all be determined and adjusted according to the specific equipment being used and the specific part being polished. Generally, the surface temperature of the diamond being polished should not be allowed to rise above 800 degrees Celsius if excessive diamond degradation will occur. Desirable surface finish of the diamond, called brilliance, generally occurs between 650 and 750 degrees Celsius.
[000305] During polishing it is important to obtain a surface finish that has the lowest possible friction coefficient, thereby providing a long-lasting, low-friction surface. After a diamond or other super hard surface is formed in modular support inserts and joints, the surface can then be polished to an Ra value of 0.3 to 0.005 microns. Acceptable polishing will include an Ra value in the range of 0.5 to 0.005 microns or less. The parts of the modular support inserts and joints can be polished individually before assembly or as a unit after assembly. Other methods of polishing PDCs and other super hard materials can be adapted to work with the modular support inserts and invented joints, with the aim of obtaining a smooth surface, with an Ra value of 0.01 - 0.005 microns. Additional polishing and grinding details are provided below.
[000306] Figure 46 shows a diamond grinding form 4601 mounted on a spindle 4602, which is in turn mounted on the high speed spindle 4603 of a CNC grinding machine. The cutting path movement 4604 of the grinding form 4601 is controlled by the CNC program which allows the necessary surface coverage that requires grinding or polishing. The axis speed is generally related to the diameter of the grinding form and the desired surface speed at the interface with the material 4605 to be removed. The surface speed should vary between 1219m and 5181m per minute (4,000 and 17,000 feet per minute) for both grinding and polishing. For grinding, the basic grinding medium for the grinding form should be as “free-cutting” as practical with diamond sand grain sizes in the range of 80 to 120 microns and concentrations ranging from 75 to 125. For polishing the grinding media should not be so “free cutting”, that is, the grinding form must be generally harder and denser with sand grain sizes ranging from 120 to 300 microns and concentrations ranging from 100 to 150.
[000307] Super hard materials can be more easily removed by grinding if the effective area of the material being removed is kept as small as possible. Ideally, the base molding form 4601 should be rotated to create conditions in the range of (6096 to 12192 meters of surface per minute (20,000 to 40,000 feet of surface per minute) between part 4605 and the base molding form 4601. Shaft pressure between part 4605 and base molding form 4601 operating in a range of 10 to 100 lb-pounds producing an interface temperature between 650 and 750 degrees Celsius is required Cooling water is required to remove excess heat in order to prevent the part from possibly failing. The simplest way to keep the grinding area small is to use a small cylindrical contact point (usually a sphere shape, although a radius end of a cylinder serves the same purpose), operating against a larger surface area.
[000308] Figure 47 shows the tangential contact area 4620 between the grinding form 4601 and the substantially larger super hard material 4621. By controlling the path of the grinding cutter, small indentations 4630 (figure 48) can be ground in the surface of the 4621 super hard material by removing the material and leaving small 4640 cusps between adjacent notches. As the notches are cut shallower and closer, the 4640 “cusps” become imperceptible to the naked eye and are easily removed by subsequent polishing operations. The cutter line path of the grinding cutter must be controlled by programming the grinding machine's CNC system to optimize spit size, grinding cutter wear and material removal rates. Base molding
[000309] The obtaining of highly polished surface finishes in PDC, PBCN and other super hard materials in the range of 0.05 to 0.005 mu.m can be obtained by passing a PDC form against the surface to be polished. “Base molding” or rubbing a diamond surface under high pressure and temperature against other super hard material degrades or burns any positive roughness remaining from previous grinding and polishing operations producing a surface finish not obtainable in any other way.
[000310] Figure 49 shows a dome part of PDC 4901 on a support 4904 and being “polished in a molded form on the base” using a molding form on the base of PDC 4902 being rotated on an axis at high speed 4903. ideally, the molding form on the base should be rotated in a range of 6069 to 12192 m per minute (20,000 to 40,000 feet per minute) with the shaft pressure operating in a range of 44.48 to 444.8 N (10 to 100 pound-force) producing an interface temperature between 650 and 750 degrees Celsius. Angle .alpha. 4905 represents the angular orientation of the geometric axis of the 4903 axis with respect to the central geometric axis of part 4901. Cooling water is generally necessary to remove excess heat to prevent the part from failing.
[000311] Figure 50 shows another modality of the base polishing technique in which the form of molding on the base PDC 5001 is controlled through a complex surface path 5002 by a CNC system of a grinding machine or a laminator CNC equipped with a high speed shaft to control the 5003 contact point of the form 5001 with a super hard component 5004. Use of cobalt chromium molybdenum alloys (CoCrMo) to increase the biocompatibility in PDCs
[000312] Cobalt and nickel can be used as catalyst metals to sinter diamond dust in order to produce synthesized PDCs. The toxicity of both Co and Ni is well documented; however, the use of CoCr alloys that contain Co and Ni has remarkable corrosion resistance and prevents the transmission of toxic effects of Co or Ni alone. The use of CoCrMo alloy as a catalyst-solvent metal in the manufacture of synthesized PDCs provides a corrosion resistant and biocompatible material. Such alloys can be defined as any appropriate biocompatible combination of the following metals: Co, Cr, Ni, Mo, Ti and W. Examples include ASTM F-75, F-799 and F-90. Each of these will serve as a catalyst-solvent metal when sintering diamond. Elementary analysis of the interstitial metal in PDC made with these alloys showed that the composition is substantially more resistant to corrosion than PDC made with Co or Ni individually. PDC interstitial metal made with these metals is substantially more resistant to corrosion than PDC made with Co or Ni and is therefore well suited for medical applications. Carbides as substrate materials
[000313] Following known procedures for the production of carbides, both Ti / TiC (TiC cemented with Ti) and Nb / Tic (TiC cemented with Nb) can be manufactured for use as substrate materials in prosthetic joints (such as joint femoral heads prosthesis hip) and components thereof. Ti (or Nb) is mixed with TiC powder and formed into a sphere enclosed by a can of Nb. The materials are then formed on a solid edge (hot isostatic compression) in a high pressure press. The result is TiC cemented with Ti or TiC cemented with Nb, producing a biocompatible product. The same result could also be obtained by sintering Ti (or Nb) + TiC using sintering procedures known as those used in the carbide industry. Ti, Nb and TiC have biocompatible materials and therefore can be used for biomedical applications such as spinal and hip implants, among others.
[000314] Micron metal and carbide powders are added together in a container with wax and acetone or another suitable solvent together with carbide mixing beads. The materials are then crushed in an attrition laminator, for example, for an appropriate period of time to thoroughly mix all components and reduce the material to the target grain size (the process is controlled to obtain a specific grain size). After grinding the solvent is evaporated and the resulting powder is then compressed in a compaction press in the desired format. The individual parts are then placed in an oven and slowly heated to burn the wax. Removal of wax too quickly will cause the pates to have excessive porosity or cause them to separate catastrophically. After removing the wax, the parts are then brought to the sintering temperature and retained until the sintering is complete. To minimize or completely eliminate open porosity, the parts can be edge formed in a standard edge forming oven in which the parts are pressurized to approximately 2068.4 bar (30,000 psi). A more extreme edge forming process is also available called rapid omnidirectional compaction (ROC). In this process, the parts are beaten in grafoil or graphite paper and placed in a pressure vessel with glass powder. The content is then brought to 8618 bar (125,000 psi) and the target temperature where the glass powder melts at which time uniformly applies pressure to the part, thereby essentially reducing the porosity to zero.
[000315] The effective temperature for sintering carbides is determined by the system in which you are working. For tungsten carbide the temperature is approximately 1200 degrees C. A typical edge forming pressure is 2068.4 (30,000 psi) whereas in the ROC process it is approximately 8618 bar (125,000 psi). the target temperature and pressure are slowly approached over several hours. When target conditions are achieved, they are retained for only minutes before the pressure and temperature are slowly decreased to room temperature and pressure.
[000316] Material formulations for carbides are determined by the end use of the material. If toughness is the desired property then the metal content of the carbide will vary from 13 to> 20% by weight. If wear resistance or low thermal expansion are the desired properties then the metal content of the carbide will be <13% by weight. Use of cemented TiC, Nb and Ti for use in prosthetic joints
[000317] A sintering and / or edge formation process can be used to create cemented TiC, Nb or Ti spheres. The spheres are then placed in a diamond Nb can between the can and the sphere. The filled can is then placed in a high pressure / high temperature press and the diamond is sintered into the sphere. Ti and Nb are useful in this sphere production process because diamond will bond chemically to TiC grains during the sintering process in a structure that is similar to the crystalline structure of diamond. The diamond will also chemically bond to Ti and Nb because both are good carbide-forming elements. The chemical bond will increase the diamond's adhesion to the substrate (ball core) and prevent the diamond from slipping off during use. Ti and Nb are used in combination with TiC because their expansion during the sintering process exceeds that of their thermal expansion coefficient (CTE), consequently a strong sphere that does not suffer a residual stress fracture is produced. The balance between the material properties of the diamond layer and the core or substrate sphere is achieved by calculating the volumetric thermal expansion of all components (= 3 * CTE * .DELTA.T, where .DELTA.T is the difference of temperature between room temperature and sintering temperature). Similarly, volumetric expansion should be calculated for all components using the following equation, (-3 * p * (1- v) / E, where p is the sintering pressure, v is the Poisson ratio and E is the modulus The CTE and the expansion are then added together for each component.The resulting values for each of the components in the diamond layer are then multiplied by their respective volumetric ratio in the diamond layer (the diamond to metal volumetric ratio is fixed). These two numbers, one for diamond and one for metal, when added together are the total volumetric change that will occur in descending from high temperature / pressure to room temperature for the diamond table, it is the volumetric change that must be matched by the core. To find this volume, multiply the combined expansion / CTE for each of the two components in the core, Ti and TiC, for example for several reasons (you must add 1) until the result is equal to the volumetric change of the diamond layer. Only the change that occurs from high pressure / temperature to room pressure / temperature is considered because under sintering conditions the diamond will sinter after having fully expanded and expanded. In this way, there will be no residual stress between them under sintering conditions. By balancing the volumetric changes between the core and the diamond layer, they will both be subjected to the same volumetric changes in cooling and depressurization resulting in little or no residual stress under conditions of ambient pressure / temperature.
[000318] It is desirable to provide more effective implantable medical devices for treating patients. For prosthetic joints, improvements in areas such as wear, biocompatibility or compatibility with other medical procedures result in a more beneficial medical device. Even small improvements in areas such as wear or biocompatibility can provide significant improvements since wear residue or metal ion elution can have a cumulative detrimental effect on a patient. A device according to the present invention incorporates a sintered carbide-metal composite with desirable strength, toughness, wear resistance, medical imaging compatibility (e.g., CT and MRI), and biocompatibility. These characteristics make the material suitable as a support surface for prosthetic joints and structural elements. The sintered carbide-metal composite also provides a surface on which an internal growth surface of soft tissue or bone can be applied. Such a surface provides attachment of the device to the patient's tissues. The internal bone growth surface could consist of spraying titanium plasma, spherical Ti bead compact or other porous coating. The sintered carbide-metal composite can also serve as an appropriate surface on which polycrystalline diamond can be applied in a high temperature, high pressure (HTHP) sintering process.
[000319] A typical device incorporating the sintered carbide-metal composite material would be an intervertebral disc replacement prosthesis implanted in the cervical spine to replace a damaged disc as shown in US no. Standard 12 / 028,740 or other artificial joint such as a hip joint as shown here. Such a device would typically consist of an upper and lower element that joins and moves through each other to provide movement. For an artificial disc, the disc would include an upper and lower prosthesis element. Each prosthesis element would have a fixation surface for fixing the element to a patient's vertebra and a pivot surface on the side opposite the fixation surface. The fixation surface would typically include mechanical features such as keels or tips that would assist in locating the disc element in the vertebra and in providing immediate provisional mechanical fixation of the device after surgical implantation. The attachment surface would also typically have a porous internal growth surface as described in the previous paragraph.
[000320] The hinge surface would include an appropriate support geometry and would typically include a sintered diamond compact forming the finished hinge surface. The second element would be similar, except that it would have a matched hinge surface corresponding to the first bearing surface. The second surface could be of the same material, or of an appropriate polymer, or other hard material, incorporated in the second element. The composite parts of diamond and sintered TiC-metal of the backing typically require grinding, grinding and polishing to obtain an accurate backing geometry with a typical surface finish of 0.10 microns Ra.
[000321] It has been discovered that a titanium carbide (TiC) composite together with an appropriate proportion of a sintering metal can be formed that has unique wear resistant, medical imaging and biocompatible properties. Titanium carbide is particularly advantageous because it is a compound that is highly chemically inert, and has highly favorable biocompatibility characteristics. Additionally, titanium carbide is composed of elements (titanium and carbon) with a relatively low atomic weight / Z number and titanium carbide is highly compatible with medical computed tomography (CT) imaging. Titanium carbide also has an extremely low paramagnetic character, and is very compatible with medical magnetic resonance imaging (MRI).
[000322] Titanium carbide can be combined with an appropriate proportion of titanium, titanium alloys, niobium, niobium alloys, tantalum, tantalum alloys, or other metals and alloys, and after exposure to pressure and / or high temperature can be sintered in a material that has unique and desirable properties. Titanium carbide is readily available in a variety of sub-micron size fractions up to 100 microns that allow modifications of sintered product characteristics to shape the product to meet toughness, wear and neutralize supporting characteristics to suit many applications.
[000323] It is preferred to use titanium powders and titanium carbide that are 44 microns in size or smaller. Titanium will sinter well with titanium carbide and is useful for making prosthetic joints in a range between approximately 6 and approximately 30 percent titanium by weight, with the remainder being titanium carbide. Both commercially pure titanium and Ti6A14V alloy work well in medical prosthetic joints when sintered with titanium carbide. The titanium band by weight in the sintered prosthesis is optimized to combine strength with a low amount of exposed interstitial metal and compatibility with sintered polycrystalline diamond if the resulting prosthesis component uses a diamond hinge surface.
[000324] Regarding the composition, titanium in the range of 6 to twenty-five (25) percent by weight produces the most desirable characteristics in the final cemented TiC part. It has also been determined that the amount of titanium can be further optimized according to the part being produced. For a larger sphere, such as a sphere approximately 40 mm in diameter, having an outer layer of sintered polycrystalline diamond, as would be used with a prosthetic hip joint, approximately 20 percent titanium with approximately 80 percent titanium carbide provides optimal results. For a smaller sphere, such as a sphere of approximately 30 mm, with an outer layer of sintered polycrystalline diamond as would be used for a hip joint, approximately 23 percent titanium with approximately 77 percent titanium carbide provides optimal results. For a joint component having a diamond pivot surface on a single side thereof, such as a spinal implant having a sintered polycrystalline diamond pivot surface, approximately 12.5 percent titanium with approximately 87.5 percent carbide titanium is great. For independent titanium carbide joint parts that do not include a diamond layer, approximately 25 percent titanium and approximately 75 percent carbide is optimal.
[000325] These compositions obtain desirable results for the specific type of prosthetic joint part. The composition varies for each different part in order to balance the compressibility and thermal expansion of the sintered titanium carbide substrate with a layer of sintered polycrystalline diamond where the diamond layer is used. The compositions also provide a desired level of hardness and toughness in the joint component. When the titanium carbide substrate is used with a diamond layer, the amount of titanium varies for different substrate sizes and shapes as different substrate volumes and geometries require different compressibility and thermal expansion to avoid cracking the diamond layer when decrease pressure and temperature after sintering.
[000326] The standard way of producing an artificial joint of the sintered titanium carbide material is by mixing the TiC and metal powders (titanium or Ti-6Al-4V) until the mixture is sufficiently uniform. The powder mixture is then loaded into cans made of niobium or another suitable refractory metal, typically in a desired shape to form a prosthetic component. Typically, a layer of diamond and sintering metal is also placed in the can against the TiC mixture to form a diamond hinge surface in the prosthetic joint component. The details of conditioning and sintering a prosthetic joint are discussed in additional detail above. The can is then loaded into an HTHP press and sintered at approximately 1400 ° C and 55 kbar. This standardized press cycle is used because the TiC mixture is typically sintered together with a layer of polycrystalline diamond (PCD) to form a prosthetic joint component. It has been found that a sintering pressure in the range of forty (40) to sixty (60) kbar, and cell capsule temperatures in the range of 800 to 1,800 degrees C, depending on the carburizing metal are required.
[000327] Typically, commercially pure titanium (CP) or Ti-6Al-4V powder is combined with TiC powder for prosthetic joint components. When TiC is combined with Ti or appropriate titanium alloys under HTHP sintering conditions, a reaction occurs between the titanium metal and TiC. A reaction phase is formed between the metal phase and the carbide phase which contains intermediate carbide-titanium compositions. This reaction phase typically creates a continuous network through all the material and separates the remaining metal and unreacted TiC. The reaction phase is largely composed of Ti3C2, which is a titanium carbide with less carbon than standard TiC. The reaction phase is typically presented as a layer of Ti3C2 that surrounds the remaining TiC and is between 5 and 15 µm thick. The temperature, pressure and time of the sintering process can be adjusted to control the growth of the Ti3C2 subcarbide phase to change the material's strength, wear resistance and toughness characteristics.
[000328] The sintered TiC composite material is typically used in combination with sintered diamond coatings that form the supporting surface of the prosthetic joint as described. The sintered diamond compacts obtain a surface that is very hard and durable and provides low friction and wear. The sintered TiC composite material, however, is also useful as a support surface articulating against itself and against polymers such as polyethylene. When the TiC composite material is properly polished, it provides an excellent wear surface with low friction and low wear in prosthetic implant support applications. Reducing the wear rate of the artificial joint is important since wear residue often irritates the body tissue around the joint in addition to destroying the joint itself.
[000329] The strength and toughness of the TiC composite material make it suitable for serving as the primary structural element of a prosthetic joint. A joint component that includes a TiC composite substrate and a sintered polycrystalline diamond compact pivot surface achieves a pivot surface with high hardness and little wear with a substrate with high toughness and strength. The sintered titanium carbide composite well matches the thermal expansion and compressibility of a polycrystalline diamond compact, allowing the diamond compact to be sintered on a substrate without problems of material expansion mismatch. The titanium carbide composite is versatile in that it can serve as a support surface, substrate for a sintered polycrystalline diamond surface and substrate for an internal bone growth coating.
[000330] The titanium-titanium carbide composite is also advantageous because titanium-based bone growth coatings can be applied directly to the surface of the material with good adhesion. Spraying of titanium plasma or porous surfaces of spherical Ti metal bead allows for easy creation of internal bone growth / biological fixation surfaces that can be applied directly to the surface of the structure as important design features of an implant. The ability to apply a titanium plasma spray or a porous spherical Ti metal bead surface directly to the artificial joint structure simplifies the resulting joint, making the joint more economical to manufacture and reduces potential points of failure.
[000331] The present sintered TiC material provides high strength and low wear in a prosthesis support application without severely compromising the quality of critical medium imaging modalities that might need to be used later in the region of the body where the implant was placed. CT scan compatibility is increased by the use of components such as titanium and carbon that have lower atomic numbers than many other relevant materials. MRI scan compatibility is increased because titanium and titanium carbides have a low magnetic character. Medium imaging compatibility is extremely important in applications where a prosthesis is placed on the spine or head, such as a temporomandibular joint prosthesis or spinal joint disc. In these scenarios, it is often desirable to perform medium imaging after an implant is present. Prior art implants for these applications can often be made from a variety of CoCrMo alloys or stainless steel. These types of materials create various image artifacts that can obscure or obliterate critical image detail, making it extremely difficult or impossible to discern anatomical details and conditions around the implant. This impairs the ability to diagnose and treat medical conditions in the region around the implant.
[000332] An improved composition for sintered titanium carbide prosthetic joint components and component substrates is thus disclosed. It will be recognized that numerous changes can be made to the present invention without departing from the scope of the claims.

权利要求:
Claims (8)
[0001]
1. Component for a prosthetic joint characterized by the fact that it comprises: a sintered carbide substrate (102, 110, 3A-51, 3A-99, 527, 4I18, 603) comprising: titanium carbide; a sintering metal selected from the group consisting of titanium and titanium alloys; a hinge surface formed on the substrate (102, 110, 3A-51, 3A-99, 527, 4I18, 603); and a structure for fixing the substrate (102, 110, 3A-51, 3A-99, 527, 4I18, 603) to a bone; and wherein the weight of the sintering metal is approximately 25 percent of the weight of the substrate and where the weight of the titanium carbide is about 75 percent of the weight of the substrate.
[0002]
2. Component according to claim 1, characterized by the fact that the component has a layer of sintered polycrystalline diamond (103, 130, 3A-52, 3A-911, 526, 4I17, 605) on one side of the same .
[0003]
Component according to claim 2, characterized by the fact that the component forms part of an artificial spine joint having a sintered diamond hinge surface.
[0004]
4. Component according to claim 1, characterized by the fact that the sintered titanium carbide forms said articulation surface.
[0005]
5. Component according to claim 1, characterized by the fact that the bone fixation surface comprises spraying of titanium plasma or a porous spherical titanium metal bead surface.
[0006]
6. Component according to claim 1, characterized by the fact that the substrate (102, 110, 3A-51, 3A-99, 527, 4I18, 603) forms a core of the prosthetic joint component.
[0007]
Component according to claim 1, characterized in that the component further comprises a layer of sintered polycrystalline diamond (103, 130, 3A-52, 3A-911, 526, 4I17, 605).
[0008]
8. Component according to claim 7, characterized by the fact that the sintered polycrystalline diamond forms the articulation surface.

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同族专利:

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公开号 | 公开日

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EP2555711A2|2013-02-13|

---

CA2795754A1|2011-10-13|

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US8603181B2|2013-12-10|

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BR112012026799A2|2017-12-12|

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AU2011237440B2|2014-06-12|

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CN102892386B|2015-03-25|

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AU2011237440A1|2012-11-01|

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WO2011127321A2|2011-10-13|

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WO2011127321A3|2012-02-23|

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EP2555711A4|2013-11-27|

---

CN102892386A|2013-01-23|

---

CA2795754C|2018-05-22|

---

US20100198353A1|2010-08-05|

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法律状态:
2018-12-26| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2019-08-20| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-08-18| B07A| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]|

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2020-12-22| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|

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2021-03-16| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-04-13| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 10 (DEZ) ANOS CONTADOS A PARTIR DE 13/04/2021, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US12/756,818|2010-04-08|

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US12/756,818|US8603181B2|2000-01-30|2010-04-08|Use of Ti and Nb cemented in TiC in prosthetic joints|

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PCT/US2011/031636|WO2011127321A2|2010-04-08|2011-04-07|Use of ti and nb cemented tic in prosthetic joints|

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