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    • 专利摘要:
    Permanent magnetic microcomposite material without rare earths and its method of obtaining. A microcomposite material based on permanent magnets composed of magnetically hard hexagonal ferrite ceramic particles and magnetically soft metal alloy particles and its manufacturing method by mechanical alloying in the presence of a coupling agent is claimed. Non-rare earth permanent magnets based on nanoparticles present a complex and expensive industrial production method. The invention describes the obtaining of a composite material based on ferrites and metal alloys of micrometric size (non-nanometer), by means of mechanical grinding methods. A product is achieved by means of a manufacturing method that is easily scalable, industrialized and of low cost, with which composite materials with favorable magnetic and microstructural properties characterized by an increase in the maximum energy product (bhmax) of up to 30% are obtained. To the majority component of ferrite. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2632107A1
    申请号:ES201600092
    申请日:2016-02-08
    公开日:2017-09-08
    发明作者:Ana María ARAGÓN SÁNCHEZ；María Pilar MARÍN PALACIOS；Antonio Hernando Grande；Stefano DELEDDA；Adrián QUESADA MICHELENA；José Francisco Fernández Lozano；Alberto BOLLERO REAL；Francisco Javier PEDROSA RUIZ
    申请人:Imdea Nanociencias；Inst For Energy Tech；Institute For Energy Technology；Consejo Superior de Investigaciones Cientificas CSIC；Universidad Complutense de Madrid；
    IPC主号:
    专利说明:

     5 Permanent magnetic micro-composite material without rare earths and its method of obtaining Technical Sector The present invention is related to magnetic materials and, in particular, falls within the sector of the manufacture of permanent magnets without rare earths. The permanent magnets 10 of the present invention are formed from isotropic composite materials based on micrometric particles of magnetically hard ferrites and magnetically soft metal type particles mechanically processed by alloying and using a coupling agent. 15 State of the art The world production of permanent magnets in the European market is 2,000 million euros and is expected to grow at an annual rate of 8% over the next 5 years. Of these, 60% of the market corresponds to magnets based on rare earths while 80% in 20 volumes are made up of ferrites. The growing demand has made it crucial to obtain higher magnetic energy densities, which is known as the magnet's energy product. This would mean the development of more efficient and sustainable technological applications, which would include engines and generators as well as applications in the medical field. 25 Currently, the market for hard magnetic materials is dominated by rare earth based compounds, which have the highest energy density values. Alnico magnets (AINiCo alloys) and hexagonal ferrites complete the market, their manufacturing, cost and application being very different. The difference is that ferrites are produced throughout the world, but the manufacture of rare earth composite magnets (NdFeB, SmCo) is focused on China, since it is where most of the mining mines are located . Being the risk of shortages a very worrying aspect today, methods have been developed to manufacture permanent magnets by reducing or even eliminating thepresence of rare earths. Thus, for example, W020 14/004595 describes a method of manufacturing permanent magnet nanocomposites where a magnetically soft phase and a magnetically hard phase are optionally mixed in the presence of surfactants and solvents. The precursor of the magnetically hard phase 5 generally has a size between I and 1000 nm although, sometimes, it can start from a powder of size between 1 and 100m. However, the soft phase precursor requires a particle size between 1 and 50 nm. The major limitation from the point of view of manufacturing industrial nanoparticles based on permanent magnets 10 is determined by the required size of the soft magnetic phase, which must necessarily be of the order of a few nanometers to obtain an effective coupling. The production of this type of compounds is thus limited since the processing of soft magnetic nanoparticles is very complex and their cost is very high. In particular, the nanoparticles of metallic materials 15 have a high surface energy and oxidize spontaneously, so that their processing can only be carried out in inert atmospheres to avoid their explosive character. Additionally, they are very agglomerated and gypsum prevents the magnetic coupling effect between the magnetically soft phase and the magnetically hard phase from being produced effectively. Industrial scaling of metal nanopalticles is established in the state of the art as a complex and expensive process. Therefore, a permanent magnet composite free of rare earths that does not require nanometric particle sizes would be desirable. The present invention proposes a rare earth-free isotropic magnetic material comprising microparticles of a magnetically hard phase, metal microparticles of a magnetically soft phase and a coupling agent. Its manufacturing is done by mechanical grinding and by a coupling agent. An easily industrializable, low-cost and rare earth product is achieved with which compounds 30 with favorable magnetic and microstructural properties that produce an increase in the maximum energy product (BHrnax) are obtained.Description A first object of the present invention relates to a permanent magnet microcomposite ("microcomposite") of rare earth without rare earths, comprising (A) nanostructured microprules 5 of a magnetically hard phase, (8) microparticles of a magnetically soft phase and (C) a coupling agent. This "microcomposite" has a controlled composition that exhibits an improvement of the magnetic properties and that can be processed in a simple, efficient and low cost way. 1 O The particle sizes of phases (A) and (8) are between 0.2 and 1 00 ~ lm. The composition of the material is between the ranges 80% -99% by weight of phase (A) 1% -20% by weight of phase (B) and 0.5% -15% by weight of the coupling agent (C) . Phase (A) has a coercive field greater than 240 kA / m and a magnetization less than 525 15 kA / m and phase (8) has a saturation magnetization greater than 910 kAlm and coercive field less than 13 kA / m. In a preferred embodiment of the invention, the following are used: as a magnetically hard phase ferrite particles of hexagonal structure of type M, 20 of nominal composition MFe12019, where M is a divalent metal such as Ba2 + or s.-2 +. -like magnetically soft phase alloys of formula TLI _ (TE, M, NM). where TL is a late transition (ferromagnetic) metallic element that is selected from Fe, Co and Ni; TE is an early transition metal, preferably Nb, Zr, Hr or Ta; M is a metalloid, preferably B, Si or P and NM is a noble metal, preferably 25 Cu, Au or Ag .. In another embodiment of the invention, the material used as a soft magnetic phase is formed by particles. of composition Fe.Col_. (O ~ x ~ l). In preferred embodiments of the microcomposite material of the invention: the phase (A) is SrFel2019 and the phase (8) has composition Fe73.5SiI6586Nb3Cul, Fe67CoIsBI4Silo a combination of both. - phase (A) is SrFel2019 and phase 8 has a Fe67CoIsBI4Sil composition - phase (A) is SrFe12019 and phase B has a Fe65C035 composition.The magnetically soft phases of the invention are characterized by micrometric sized particles that have a nanostructure consisting of regions with different crystallographic orientation with dimensions <100 nm. These regions are a consequence of the process of obtaining microparticles of magnetically soft phases. In a preferred embodiment, the coupling agent is a surfactant or surfactant, which is a substance that influences the surface tension on the contact surface between two phases. It is an amphiphilic molecule characterized by having a water soluble (hydrophilic) polar chain end and a water insoluble (hydrophobic) insoluble end. These types of molecules with double affinity for the same solvent are characterized by being adsorbed by the surface of metal particles when used above a certain concentration, forming micelles. Depending on the power of dissociation, presence of an electrolyte and its physicochemical properties, surfactants can be classified as: 20 Ionic Surfactants: according to the charge of the part that presents the surface activity, being able to be of type (a) anionic, (b) cationic and (c) amphoteric. Non-ionic surfactants. They can be natural and industrially processed. Natural fatty acids such as carboxylic acids with long unbranched hydrocarbon chains (4 to 24 carbon atoms) are preferably used. In a particular embodiment of the object of the invention, common acids such as palmitic, stearic, oleic, linoleic, linolenic and their combinations are used as coupling agent. Preferably the coupling agent is oleic acid. The permanent magnet microcomposite materials of the present invention, based on the combination of magnetically hard ferrites, for their high anisotropy, and soft magnetic phases, for their high saturation magnetization and low coercive field, and a coupling agent, have object of the increase in energy efficiency through a process of dipole interaction between the soft and soft phases and are shaped like particles. The isotropic permanent magnet microcomposite materials of the present invention have the following advantages. Its energy density is higher than that of ferritescurrent commercial, which allows, once compacted, compete with magnets based on low-energy rare earths (with anisotropic energy products between 40 and 100 kJ / m3). The price of the material of the present invention has been estimated at about 5 euros / kilo, while the average price of the rare earth-based magnets of the market is close to 100 euros / kilo. The corrosion resistance of the permanent magnet microcomposite materials of the present invention is greater than that of permanent magnets based on metal alloys containing rare earths. The particle size of the microcomposite materials of the present invention without rare earths is micrometric, in contrast to the state of the art in rare earthless permanent magnets 10 of improved energy product requiring materials of nanometric size. The micrometric dimension of the microcomposite material of the present invention facilitates the integration into production lines at a reasonable cost. A second object of the present invention is a method of manufacturing the permanent magnet microcomposite materials without rare earths, based on the mixture of particles of two initial compounds and a coupling agent: (A) M-type hexaferrite ceramic particles magnetically hard, isotropic (B) particles of magnetically soft metal alloys (defined above) or magnetically soft particles of FeCo base (defined above). 20 25 30 The method of manufacturing permanent magnet microcomposite materials without rare earths comprises the following stages: a. Conditioning of the particle size of the hard magnetic phase (A) to obtain particle sizes between 0.2 and 100 µl. b. Conditioning of the size of the soft magnetic phase (B) to obtain particle sizes between 0.2 and 100 m. C. Mixed by mechanical ball grinding, phase (A) and phase (B) together with a coupling agent (C) using a solvent. d. Heat treatment of the mixture In a preferred embodiment, the phase (A) is SrFel2019 and the conditioning of the soft magnetic phase (B) is carried out from amorphous tapes of FeSiB or FeCoSiB base composition which are subjected to a treatment preheating in an inert atmosphere to induce controlled nanocrystallization and fragilize the samples and subsequently to mechanical grindingto reduce the size of pal1icle. Preferably, phase B has a composition Fe73.5SiI6.5B6Nb3CUl and Fe67ColsBl4Si1, more preferably Fe67ColSBl4Sil. In another preferred embodiment, the conditioning of the soft magnetic phase (B) is carried out by alloy by mechanical grinding of Fe and Co microparticles, obtaining Fel-xCo microparticles. The mixing stage c) can be by mechanical milling by dry, mechanical by wet and / or cryo-grinding and stage d) heat treatment of the mixture obtained in stage c) is carried out in an inert atmosphere at a temperature between 50 ° C and 400 ° C. The percentage of coupling agent that is maintained in the microcomposite material after step d) is at least 10% with respect to the coupling agent incorporated in step c). This coupling agent (C) is an oleic acid type surfactant in combination with a solvent such as hexane. Preferably, oleic acid is used as a coupling agent in combination with: 15 (i) ferrite ceramic pallets as a hard phase of hexagonal structure of type M, of nominal composition MFel2019 (MO'6Fe203), where M is a divalent metal as Ba2 +. Sr2 and (ii) metallic alloy particles with FeSiB and FeCoSiB base as a soft magnetic phase with saturation magnetization greater than 910 kA / m and coercive field less than 13 20 kA / m. The presence of the surfactant or surfactant in the microcomposite material of the present invention allows coupling between hard and soft magnetic phase particles. This coupling agent favors the geometric distribution of particles in both the hard-hard and soft-phase interfaces so that the magnetic energy density is increased. The coupling agent also acts as a protector of atmospheric degradation by being located on the outer surface of the particles and avoiding oxidative processes. 30 A particular aspect of the present invention relates to the method of conditioning the magnetically soft particles by mechanical grinding to obtain particle sizes below 100 µL. The conditioning of the magnetically soft particles is made from amorphous ribbons of FeSiB or FeCoSiB base composition that undergoes a heat treatment prior to 550 oC in an inert atmosphere, and subsequently proceeds to different methods of mechanical grinding in order to reduce the size of the film toscale below 100 flm .. This process favors the nanostructuring of magnetically soft particles generating regions with different crystallographic orientation with dimensions <100nm. 5 The magnetically soft material particles are preferably obtained by mechanical grinding of high energy balls by dry and / or wet route in the presence of coupling and cryo-grinding agent. During the process of mechanical grinding of high energy balls dry the material is fractured continuously. By means of mechanical grinding routes by wet way, the formation of agglomerates is prevented, obtaining smaller and dispersed particles through the use of surfactants and solvents. In a preferred embodiment, the grinding is carried out at the temperature of the liquid nitrogen and the sample is embrittled, so that more severe plastic deformations occur during the criomolienda process. Cryomolienda allows greater control of the milling process, since during high-energy ball milling, very high temperatures can be reached, above 500 ° C. In this way, the formation of more homogeneous samples with lower particle sizes in lower grinding times than with 20 grinding at room temperature is favored. In another preferred embodiment of the present invention FeCo alloy particles are also used as the soft magnetic phase. This powder was prepared by mechanical grinding of balls by dry route, obtaining particle sizes between 0.5 and 1 00 ~ lIn. Fel_xCox 25 alloy particles were obtained by a high-energy grinding process in jars and with tungsten carbide balls made in an air atmosphere, at 300 revolutions per minute (rpm), using grinding times between 3 and 24 hours .. The process of obtaining the alloy in high-energy grinding provides microparticles that are nanostructured and have regions with crystallographic orientation <1 OOnm within 30 microparticles. The saturation magnetization of this soft compound ranges between 1540 and 1680 kA / m, its coercive field is less than 13 kA / m Oe and the particle sizes range between 0.2 and 100 microns.Regarding the magnetic properties of the nanostructured soft magnetic particles, they are characterized by saturation magnetization values greater than 910 kA / m and coercive field values less than 13 kA / m. In the present invention, high-energy mechanical wet milling is used as a method for the manufacture of permanent magnet microcomposites without rare earths, so that there is control over the microstructure of the samples, it being possible to obtain a homogeneous dispersion of two types of magnetic and structurally different materials that favor the formation of interfaces that improve the magnetic performance of the hybrid compound through the use of a coupling agent. The solvent used in step c) is an aliphatic alkane hydrocarbon, such as hexane, but not limited to said solvent. The magnetic materials of the present invention are preferably conditioned by mechanical ball milling processes and subsequent heat treatments in a controlled inert atmosphere at temperatures between 50 ° C and 400 ° C. The heat treatment is characterized by removing the solvent using step b) and partially removing the coupling agent (C). The weight percentage of the coupling agent that remains in the microcomposite after step d) is at least 10% of the coupling agent dosed in step c). The magnetic properties of the microcomposites of the present invention increase the maximum energy product by 25-30%, reaching values between 13 and 15 kJ / m3, as a result of an increase in the remanence magnetization of up to 15%, an increase in saturation magnetization of up to 20% and a minimum decrease in coercivity of up to 30%. The permanent magnet microcomposites of the present invention have the following advantages: 30-Their energy density is higher than that of current commercial ferrites, which allows, once compacted, to compete with magnets based on rare low-energy tiers ( with anisotropic energy products between 40 and 100 kJ / m3).5 10 -Its manufacturing cost has been estimated at 5 euros / kilo, while the average market price of rare earth-based magnets is estimated at around 100 euros / kilo. -Its corrosion resistance is greater than that of rare earth-based magnets. Its particle size is micrometric, in contrast to the current existing patents focusing on nanometer-sized materials, which facilitates its integration into production lines at reasonable cost. -Its scaling process is simple and approachable by the existing industrial equipment in the state of the art, thus favoring its industrialization. A third aspect of the present invention constitutes the use of the microcomposite material in applications such as permanent magnet, in particular in motors, generators and actuators and particularly in motors of mechanical traction vehicles. The materials of the present invention offer the possibility of replacing permanent magnets, based on low-end rare earths (BHmax between 10 and 30 J / m3), with rare earth materials in devices containing motors, actuators and / or generators . In particular, the materials of the present invention have application in traction vehicles, in electric motors of bicycles and motorcycles. 20 Description of the Figures Figure 1 a shows a scanning electron microscopy micrograph, MEB, of the material SrFel2019 used, ceramic particles are observed whose morphology is characterized by having hexagonal platelets having a size between 0.2 and 2 / lm, with an average value of 0.6f.lm. Figure LB shows a MEB micrograph of magnetically soft particles of Fe73.sSi 16.sB6NbJCul composition that have been ground in high energy grinding with cryogenic cooling for 5 hours. Palticles with a granular morphology and a particle size between 0.5 and 3 / lm are observed, with an average value of I / lm. Figure Ic shows a MEB micrograph of Fe67CoIsBI4Sil cryololide composition films for 5 hours. Palticles with granular morphology and a particle size between 0.5 and 3 / lm are observed, with an average value of 0.7 / lm.Figure 2 shows a MEB micrograph of a permanent magnet material of the present invention consisting of a composite consisting of 95% by weight of SrFel2019 particles and 5% by weight of Fe73s Si 16.5B6Nb3Cul micrometric particles obtained after 5 5h of cryo-grinding. For the manufacture of the composite, mechanical ball milling has been used wet for 1 hour, followed by a heat treatment at 200 ° C for 1 h in an inert atmosphere. Figure 3 shows the demagnetization curve (second quadrant of the hysteresis cycle) as a function of the effective magnetic field of the samples: (1) initial SrFel2019 and three types of manufactured compounds, (2) [95% SrFel2019 -5% FeSiB ] and (3) [95% SrFel2019 + 5% FeCoSiB], and (4) [95% SrFeI2019 + 5% Fe6SC03S]. The variation of the product (B · H) is shown in Figure 4 as a function of the magnetic flux density B of the samples: (1) initial SrFe12019 and three types of manufactured compounds, (2) [95% SrFel2019 -5 % FeSiB] and (3) [95% SrFe12019 + 5% FeCoSiB], and (4) [95% SrFeI20é5% Fe6SC03S]. Figure 5 shows the curves of the derivative of Ms (H) and Mr (H) as a function of the applied field obtaining the distribution of inversion fields for the following samples: (l.) SrFe12019, (2.) [ 95% SrFel2019 -5% FeSiB]. Embodiment of the invention. The present invention is illustrated by the following examples, which are not intended to limit its scope. Example 1. Conditioning of the soft magnetic phase particles of FeSiB or FeCoSiB base composition This example shows the procedure for conditioning the soft magnetic phase particles of FeSiB or FeCoSiB base composition. Initially, (1) amorphous tapes of the composition Fe73.sSiI6.5B6Nb3Cul and 35 Fe67CoIsBI4Sil were obtained by fusion of the components and the subsequent use of techniques ofultrafast cooling; (2) the amorphous tapes were subjected to a heat treatment to induce controlled nanocrystallization and fragilize the samples; and, finally, (3) different methods of mechanical grinding were carried out in order to reduce the particle size. 5 In process (2), therefore, crystallization of initially amorphous tapes was induced. The tapes were preferably heated to the crystallization temperature and then the oven was turned off to allow the sample to cool slowly until it reached room temperature. Regarding the parameters considered in this stage were: (i) annealing temperature between 520 and 580 ° C, (ii) heat treatment time between 30 and 90 minutes, (iii) inert atmosphere. The coercive field values of the resulting material are between 0.8 and 1.6 kA / m, with saturation magnetization values between 73 I and 798 kAlm for the Fe73.5Si¡6sB6Nb3Cu¡ tape and between 10 1 OY 1083 kA / m for the composition Fe67Co¡sB¡4Si¡. And 15% magnetization values were obtained between 465 and 598.5 kA / m for the Fe735Si¡65B6Nb3Cu¡ tape and 578-722 kA / m for the Fe67Co¡sB¡4Si¡ tape. The conditioning process of the present invention consists in the mechanical grinding (3) of high energy balls having been carried out in a high-energy planetary ball mixer mill 20 type SPEX (MM400 Retsch). The cryo-grinding has been carried out in a SPEX mill (Model 6770-Freezer / Mill) at liquid nitrogen temperatures (-196 ° C). The parameters considered for high-energy grinding (3) were: (i) oscillation frequency between 400 and 1500 rpm, (ii) using two tungsten carbide jars with a capacity between 5 and 30 ml, (iii) balls Tungsten carbide with a diameter between 5 and 20 mm, (iv) 26: 1 ball-to-powder weight ratio, (v) surfactant: 10% by weight oleic acid for high wet energy milling, (vi) solvent: 50% by weight of hexane with respect to the solid for high wet energy grinding, (vii) grinding time between 10 min and 12 hours for dry grinding and between I and 6 hours for wet grinding. For the 30 cryololienda stainless steel jars between 10 and 30 ml and a 5 cm long stainless steel bar were used. The particles obtained by high-energy dry milling have a particle size between 0.4 and 40 µm with an average size of 4 µm. In the case of wet milling, the particles obtained were smaller thanobtained in the case of dry milling, because with the use of surfactants and solvents the formation of agglomerates decreases, and more dispersed particles are obtained, so that a particle size between 0.3 and 50 is reached / lm with an average size of I / lm. By means of the cryololienda, an additional advantage is achieved in the reduction of the particle size and a greater homogeneity in the distribution of particle sizes for processes with grinding time lower than the previous cases, the particle size obtained being between 0.5 and 3 ~ lm with an average size of 0.7 / lm. These particles have a microstructure characterized by the formation of an aFeSi bcc crystalline phase in the Fe base and aCo fcc alloys in FeCo 10 type alloys evenly distributed in a residual amorphous matrix, the characteristic size of these crystals being ca . 10 nm (determined by Transmission Electron Microscopy, MET). In addition, these soft magnetic phase nanostructured particles have a swap length of about 2 µl which is advantageous for the purpose of the present invention. 15 The magnetic properties of these samples, in all types of grinding, are maintained, are soft, obtaining coercive fields between 0.24 and 4 kAl, remanence magnets between 5.6 and 28 kA / me saturation magnets between 840 and 1470 kAlm. 20 Table 2 shows the average particle size (D) and the coercivity (Hc), saturation (Ms) and remanence (Mr) values presented by the soft magnetic phase particles conditioned by cryololienda. The samples are designated as follows: Fe because it is a sample rich in iron or FeCo if it is a sample rich in Fe and Co, followed by the temperature of the heat treatment and finally the time of milling in hours. Table 2 Sample He Ms Mr D (kAlm) (kA / m) (kAlm) (JJm) Fe-550-5h tape 1.5 958 7.3 I FeCo-550-5h tape 5.9 1451 41.1 0, 7 30 Example 2. Conditioning of the soft magnetic phase particles of the base composition Fe l-xCox.This example shows the conditioning of magnetically soft particles of FeJ_.Co • base composition. Initially (1) it is based on a mixture of particles composed of 65% by weight of Fe 5 (Sigma-Aldrich 97%, 325 ~ lm) and 35% by weight of Co (Sigma-Aldrich 99.8%, 2 ~ n ), (2) the alloy was then processed by mechanical grinding of dry balls. The mechanical grinding (2) of dry balls has been carried out in a planetary ball mill type SPEX (Pulverissette 5 classic line, Fritsch). 10 The parameters considered for grinding (3) were: (i) oscillation frequency that should be between 50 and 400 rpm, (ii) using two jars of tungsten carbide with a capacity between 80 and 500 ml, (iii) balls Tungsten carbide with a diameter between 0, 1 and 40 mm, (iv) 30: 1 ball-to-powder weight ratio, (v) grinding time between 3 and 24 hours. 15 The particles obtained have a particle size between 0.5 and 100 µL. The exchange length of said particles is 26 nm. As for the magnetic properties of these crystalline samples, the soft magnetic properties are maintained, obtaining coercive fields between 3 and 15 kAlm, and saturation magnets between 1645 and 1974 kA / m. Table 3 shows the average particle size of the FeCo powder (D) and grain size (d) and the coercivity (Hc), saturation (Ms) and remanence 25 (Mr) values presented by these Soft magnetic powders obtained by cryololienda. Table 3 Sample He Ms Mr D (kA / m) (kAlm) (kAlm) (~ m) Fe65Co35-12h 3.42 1892 25 0.2-5 30 Example 3. Obtaining permanent magnet microcomposites from magnetic phases hard and soft magnetic phases by grinding with a coupling agent.In a specific example of the invention, a mixture of 95% by weight of SrFe12019 (high coercive field, between 318 and 399 kA / m) and 5% by weight of powder of Fe735SiI6.5B6Nb3Cul, Fe67CoIsBI4Sh and Fe65C035 (high saturation magnetization, between 980 and 1680 kA / m); conditioned according to examples 1 and 2. The parameters involved in the milling process were the following: (i) oscillation frequency between 400 and 1500rpm, (ii) 2 stainless steel jars with a capacity between 5 and 30 ml, (iii) 2 balls of 5 and 10 mm in diameter, (iv) 1: 1 balls-powder weight ratio, (v) grinding time between 1 and 4h, (vi) and 10% by weight of Oleic Acid (with a purity> 99%, Sigma 10 Aldrich) as a surfactant, (vii) and 50% by weight of Hexane (with a purity of 95%, Sigma Aldrich) as a solvent. Regarding the parameters involved in the second stage of heat treatment of the sample, the parameters considered were: (i) temperature of 200 oC and, (ii) annealing time between 4h, (iii) in an inert Argon atmosphere. After heat treatment the weight percentage of the coupling agent of the microcomposite material was 1.85%. Although the average soft phase particle size is well above the critical threshold value defined for "spring magnet" type materials, so that there is a magnetic coupling by exchange, an extraordinary increase in the magnetic properties of the composites, obtaining an increase of 25-30% of the maximum energy product (13-15 kJ / m3), as a result of an increase in the magnetization of remanence of 15% (an increase in the saturation magnetization of 17% and a decrease of only 30% in coercivity - see table 3). 25 By representing the derivative of the isothermal remanence magnetization (dM: CH)) together with the derivative of the demagnetization remanence magnetization (dM ~ (H)), against an applied magnetic field, the susceptibility of irreversible processes (Xirrev). Analyzing the peak of the derivative, the distribution of the investment field of the composites was obtained. The curves, shown in Fig. 4, showed how the two magnetic phases (hard 30 and soft) revert their magnetization independently, and therefore are decoupled. Being able to observe an increase in the coercivity of remanence with respect to the intrinsic coercive field, because the reversible rotation of the soft phase occurs at not very high fields so that the magnetically hard phase is reversed.5 Table 3 shows the values of coercivity (He), saturation magnetization (Ms) and remanence (MI ') presented by these permanent magnet microcomposites without rare earths. Table 3 Sample He Ms Mr (BH) max (kA / m) (kA / m) (kA / m) (kJ / m3) SrFel2019 360 352 212 11.5 95% SrFeI2019 + 5% FeSiB 262 410 265 14.9 95% SrFeI2019 + 5% FeCoSiB 256 417 266 15 95% SrFeI2019 + 5% Fe6SC03S 265 429 236 12 The decoupling between hard and soft phases is at the origin of high coercive field values. The magnetostatic fields prevent the decrease in the value of the 10 remanence, and favor a greater remanence (the remanence is greater for microcomposites based on the FeSiB and FeCoSiB base metal alloys, with high exchange correlation lengths, than for those based on Fe6SC03S alloys). 
    权利要求:
    Claims (22)
    [1]
    l. Rare earth free permanent magnet microcomposite material comprising (A) microparticles of a magnetically hard phase, (B) nanostructured microparticles of a magnetically soft phase and (e) a coupling agent.
    [2]
    2. The material of claim 1, wherein the particle sizes of phases (A) and (B) are between 0.2 and 100 µl. 10
    [3]
    3. The material according to claims 1 and 2 where the composition is comprised between the ranges 80% -99% by weight of phase (A) and 1% -20% by weight of phase (B) and 0.5% -15% in coupling agent weight (C).
    [4]
    4. The material according to claims 1 to 3 where phase (A) has a coercive field greater than 240 kA / m and a magnetization of less than 525 kAlm; and phase (B) has a saturation magnetization greater than 910 kAlm and a coercive field less than 13 kA / m. twenty
    [5]
    5. The material according to claims 1 to 4 where phase (A) is SrFel2019 and phase (B) has composition Fe73.sSiI6.5B6Nb3eul, Fe67eolsBI4Sil or a combination of both.
    [6]
    6. The material according to claims I to 4 where phase (A) is SrFel2019 and phase (8) has a composition Fe67eolsBl4Sil.
    [7]
    7. The material according to claims I to 4 where phase (A) is SrFel2019 and phase (B) has composition Fe6Se035.
    [8]
    8. The material according to claims I to 7 wherein the coupling agent is a surfactant. 30
    [9]
    9. The material according to claim 8 wherein the coupling agent is oleic acid.
    [10]
    10. Method of manufacturing the material of claim 1 comprising: a. Conditioning of the particle size of the hard magnetic phase (A) to obtain particle sizes between 0.2 and 100 / lm.5 10 b. Conditioning of the particle size of the soft magnetic phase (8) to obtain nanostructured particle sizes between 0.2 and 100 µm. c. Mixed by mechanical ball milling, phase (A) and phase (8) together with a coupling agent (C) using a solvent. d. Heat treatment of the mixture.
    [11]
    11. Method of manufacturing the material according to claim 10 wherein phase (A) is SrFeJ2üJ9.
    [12]
    12. Manufacturing method of the nanostructured material, according to claim 10, where the conditioning of the soft magnetic phase (B) is carried out from amorphous ribbons with a FeSiB or FeCoSi8 base composition that are subjected to a prior heat treatment in an inert atmosphere to induce controlled nanocrystallization and embrittle the samples and, subsequently, mechanical grinding to reduce the particle size.
    [13]
    13. Manufacturing method of the nanostructured material, according to claims 10 and 11, where phase 8 has a composition Fe73.sSiJ6.s86Nb3CuJ and Fe67CoJ8BJ4Sil. twenty
    [14]
    14. Manufacturing method of the nanostructured material, according to claims 10 and 11, where the phase (8) has a composition Fe67CoJ88J4Sil.
    [15]
    15. Manufacturing method of the nanostructured material according to claim 10, wherein the conditioning of the soft magnetic phase (8) is performed by alloying by mechanical grinding of Fe and Co microparticles, obtaining FeJ_ xCo microparticles. 30
    [16]
    16. Manufacturing method of the nanostructured material, according to claims 10 and 15, where the phase (8) has a composition Fe6sCo3s.
    [17]
    17. Method of manufacturing the material, according to claims 10 to 17, where the composition is comprised between the ranges 80% -99% by weight of phase (A) and 1% -20% by weight of phase (8) and 0.5 % -15% by weight of the coupling agent (C).
    [18]
    18. Method of manufacturing the material, according to claims 10 to 18, where the mixing step a) can be by means of mechanical dry grinding, mechanical wet grinding and / or cryo-grinding. 5
    [19]
    19. Method of manufacturing the material, according to claims 10 to 19, where stage d) of thermal treatment of the mixture obtained in stage c) is carried out in an inert atmosphere at a temperature between 50 ° C and 400 ° C.
    [20]
    20. Method of manufacturing the material, according to claims 10 to 20, where the percentage of coupling agent that remains in the microcomposite after step d) is at least 10% with respect to the coupling agent incorporated in step c) . fifteen
    [21]
    21. Use of the claimed material in permanent magnet applications, in particular in motors, generators and actuators.
    [22]
    22. Use of the claimed material in applications as a permanent magnet in mechanical traction vehicle engines.
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    同族专利:
    公开号 | 公开日
    WO2017137640A1|2017-08-17|
    ES2632107B2|2018-01-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US10332661B2|2011-07-14|2019-06-25|Northeastern University|Rare earth-free permanent magnetic material|ES2848873B2|2020-02-11|2021-12-21|Consejo Superior Investigacion|PROCEDURE FOR OBTAINING A MAGNETICALLY ANISOTROPIC AND DENSE PERMANENT CERAMIC MAGNET|
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