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    • 专利摘要:
    A high temperature piezoelectric ceramic material of bisco3 -pbtio3 chemically designed to enhance the voltage response, and a method to obtain said ceramic material. The invention relates to a high temperature piezoelectric ceramic material of bisco3 -pbtio3 of formula bi1-x 2y pbx-3y sc1-x tix or3, where x varies from 0.64 to 0.68 and it varies from 0.01 to 0.025, which includes a point defect under design to enhance the voltage response. In addition, the invention relates to a method for obtaining said ceramic material by conventional sintering of nanocrystalline powders synthesized by mechanochemical activation of a stoichiometric mixture of precursors. Finally, the invention also relates to the use of the ceramic material bisco3 -pbtio3 chemically designed as part of detector devices and magnetic field detection devices. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2620690A1
    申请号:ES201531920
    申请日:2015-12-29
    公开日:2017-06-29
    发明作者:Miguel ALGUERÓ GIMÉNEZ；Harvey AMORÍN GONZÁLEZ；Alicia CASTRO LOZANO
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；
    IPC主号:
    专利说明:

    A HIGH TEMPERATURE PIEZOELECTRIC CERAMIC MATERIAL OF BiScO,PbTiO, DESIGNED CHEMICALLY TO POWER THE RESPONSE IN VOLTAGE.AND A PROCEDURE TO OBTAIN SUCH CERAMIC MATERIAL
    The invention relates to a high temperature piezoelectric ceramic material of BiSc03-PbTi03 of the formula Bi "K.¡-2yPbK.3ySc" KTiK0 3, in which x varies from 0.64 to 0.68 and varies from 0.01 to 0.025, which includes a point defect under design to enhance the response in
    10 voltage Furthermore, the invention relates to a process for obtaining said ceramic material by conventional sintering of nanocrystalline powders synthesized by mechanochemical activation of a stoichiometric mixture of precursors. Finally, the invention also relates to the use of the chemically designed BiSc03-PbTi03 ceramic material as part of detector devices and field detection devices
    15 magnetic.
    STATE OF THE TECHNIQUE
    The BiSc03-PbTi03 system is the most promising system among solid solutions
    20 with a perovskite structure of the general formula BiM03-PbTi03, in which M is a trivalent cation in octahedral coordination, with electromechanical response boosted at the boundary between ferroelectric morphotropic phases (English acronym MPB corresponding to ferroelectric morphotropic phase boundaries), and high temperature of Curie. This material has been extensively investigated as an alternative to the state of the art Pb (Zr, Ti) 03 (PZT)
    25 to expand the operating temperature of high sensitivity piezoelectric ceramics above 200 oC to 400 oC.
    Specifically, the binary system (1-x) BiSc03-xPbTi03 presents an MPB between the ferroelectric polymorphic phases of rhombic symmetries R3m and tetragonal P4mm at 30 x-0.64, a composition for which the Curie Te temperature is :::: : 450 oC, typically achieving piezoelectric coefficients d33 of -450 pC N- 'after polarization. This Te is 100 oC above that of Pb (Zr, Ti) 0 3, as the piezoelectric coefficient d33, which also significantly exceeds the figure of - "= '245 pe N" for ceramics of the last material
    in its own MPB. In addition, the piezoelectric load coefficient is comparable to those of the high sensitivity piezoelectric ceramic materials available in the market for chemically modified PZT.

    However, and despite the theoretically extended range of operating temperature, enabled by the high Curie temperature, the BiScOTPbTi03 cannot be used directly in most applications. This is the case of detection technologies such as accelerated meters, vibration measurements, hydrophones or magnetic field detectors, for which the key parameter is the piezoelectric coefficient of voltage g33, instead of the piezoelectric coefficient of charge d33. This coefficient is equal to d33 multiplied by reciprocal permittivity, which is very low (or very high permittivity) in polarized BiScOJ-PbTi03. Therefore, and for the reasons stated above, it is necessary to develop new BiSc03-PbTi03 materials optimized for specific applications.
    DESCRIPTION OF THE INVENTION
    The present invention discloses a piezoelectric ceramic material of BiScOJ-PbTi03 of the formula Bi1_x + 2yPbx.3ySc, .xTix0 3, in which x varies from 0.64 to 0.68 and y ranges from 0.01 to 0.025, which exhibits an electromechanical response enhanced at a boundary between morphotropic phases with perovskite structure and rhombic symmetries R3m and tetragonal P4mm, a high Curie temperature and the inclusion of a point defect under design to enhance the voltage response.
    In addition, the high temperature piezoelectric ceramic, high sensitivity and enhanced voltage response of the present invention has a highly homogeneous and dense fine grain microstructure with an average grain size that can be adjusted between 1.0¡1m to 2 , 5 ... 1m. Specifically, ceramic materials with x = 0.64 and y = 0.01 have a Curie temperature of 395 oC, and a g 33 coefficient of 4.8 x 10-2V m N-1.
    Furthermore, the present invention discloses a process for obtaining said ceramic material which refers to its preparation by conventional sintering of nanocrystalline powders synthesized by mechanochemical activation of precursors in a high-energy planetary mill. This procedure, based on highly reactive powders, allows the suppression of volatilization of PbO and Bi20 3 during high temperature sintering, so that stoichiometric mixtures of the precursors can be used (Bi203, SC20 3, PbO, Ti02 and Mn20 3) , while avoiding the need to control the atmosphere during the final heat treatment by burying the pieces in powdered green during sintering. This is very advantageous for precise control of the composition and the coexistence of phases, during the inclusion of the point defect under design, which could not be reproducibly achieved by conventional ceramic technologies such as

    solid state synthesis by precursor heating.
    A first aspect of the present invention relates to a piezoelectric ceramic material characterized in that it has
    5 • the general formula Bil. ~ + 2yPb ~ .3ySC1. ~ Ti ~ 03, in which x varies from 0.64 to 0.68 e and varies from0.01 to 0.025;
    • a single phase located on the border between morphotropic phases with perovskite structure and R3m and tetragonal P4mm rhombohedral symmetries; Y
    • a microstructure with an average grain size between 1.0¡1m and 2.5¡1m. 10
    The piezoelectric ceramic material of the present invention has a unique phase located on the border between morphotropic phases with perovskite structure and R3m and tetragonal P4mm rhombohedral symmetries, which is responsible for the high piezoelectric response and, in addition, includes a point defect under design to enhance the answer
    15 in voltage that makes the material suitable for use in detection technologies.
    The term "punctual defect under design" refers to a punctual defect that is introduced at or around a particular site of the unit cell of the perovskite structure AB03 • specifically by controlled substitution of Pb2 + with Bi3 + at site A
    20 (cuboctahedral coordination), together with the formulation of a vacancy of Pb for every two substitutions for load compensation. This controlled substitution that does not require additional chemical species, but the introduction of a non-stoichiometry at site A, results in a significant increase in the rigidity of the crystalline network and, therefore, a decrease in dielectric permittivity and elastic modules. In addition, this is achieved
    25 while the material remains on the border between morphotropic phases with perovskite structure and R3m and tetragonal P4mm rhombohedral symmetries, which is a requirement for a high piezoelectric response.
    Additionally, the microstructure is also controlled during the inclusion of the punctual defect 30 under design, so that a fine, homogeneous and dense fine-grained microstructure is obtained optimized for optimal mechanical properties.
    In a preferred embodiment, the piezoelectric ceramic material of the present invention has a homogeneous and dense fine grain microstructure with an average grain size of between 1.0 iJm and 1.5¡1m.

    In another preferred embodiment of the present invention, the aforementioned piezoelectric ceramic material has the formula
    5 A second aspect of the present invention relates to a method forobtain the aforementioned piezoelectric ceramic material, characterized bywhich comprises the following stages:
    a) synthesis of a nanocrystalline powder of formula Bi'.x + 2yPbx.3ySC'.xTix03, in which x varies from 0.64 to 0.68 and y varies from 0.01 to 0.025 by mechanochemical activation of a stoichiometric mixture from 820 3, SC20 3, PbO and Ti02; and b) sintering of the nanocrystalline powder obtained in step (a) in a temperature range between 1100 oC and 1150 oC. Step (a) is preferably performed in a planetary mill at 300 rpm for 20
    h.
    In a preferred embodiment, step (a) is performed for the synthesis of a nanocrystalline powder of formula Bi1-x-tzyPb ~ .JySc,. ~ Ti ~ OJ, in which x is 0.64 and y is 0.01.
    A third aspect of the invention relates to a piezoelectric ceramic composite 20 comprising
    • the piezoelectric ceramic material according to any of the claims
    1 to 3; Y
    • a magnetostrictive material.
    25 The term "magnetostrictive material" refers to a ferromagnetic material that changes its shape or dimensions during the magnetization process.
    In a preferred embodiment, the magnetostrictive material that forms the piezoelectric ceramic composite material is selected from the list consisting of Terphenol-D, 30 Metglass, and oxides with spinel structure of formula AFe20 4, in which A is Ni, Ca or a
    combination thereof, and a combination thereof.
    In another preferred embodiment of the present invention, the aforementioned piezoelectric ceramic composite material is of the particulate, fiber or laminate type.
    Another aspect of the present invention relates to the use of ceramic material

    piezoelectric as described above, as part of a detector device. Examples of sensing devices are accelerometers, vibration detectors or hydrophones. The piezoelectric ceramic material of the present invention is the active element in these detection technologies.
    The last aspect of the invention relates to the use of the piezoelectric ceramic composite described above as part of a magnetic field detection device, functioning as a magnetoelectric transducer. The piezoelectric ceramic composite material of the present invention, which comprises the piezoelectric ceramic material also object of the present invention and a magnetostrictive material, is the active element in magnetic field detection technologies.
    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as that usually understood by a person skilled in the art to which this invention belongs. Similar or equivalent methods and materials those described herein can be used in the practice of the present invention. Throughout the description and the claims, the word "comprises" and its variations are not intended to exclude other technical characteristics, additives, components or steps. The objects, advantages and additional features of the invention will be apparent to those skilled in the art after examining the description, or can be learned by the practice of the invention. The following examples and drawings are provided by way of illustration and are not intended to limit the present invention.
    BRIEF DESCRIPTION OF THE DRAWINGS
    FIG. 1 XRD patterns for ceramic samples of Bil.x + 2yPbx_3ySC1_xTix03 with x = 0.64 ey = 0, 0.01 and 0.025, which show the absence of second distinct phases of perovskite for a low concentration of the point defect under design .
    FIG. 2 XRD patterns for ceramic samples of Bil_x + 2yPbx.3ySC1_xTix03 with x = 0.64 ey = 0, 0.01 Y0.025 Y improved statistics through the diffraction peak 200 of the high temperature cubic phase, which they show the coexistence of polymorphic phases and their displacement towards the rhombohedral phase.
    P201 531920
    FIG. 3 Scanning electron microscopy (SEM) images for ceramic samples of Bil_x + 2yPbx_3ySC1_xTix0 3 with x = 0.64 and y = 0, 0.01 and 0.025, which show a homogeneous and dense fine grain microstructure.
    FIG. 4 Scanning electron microscopy (SEM) images for Bil.x ceramic samples ... 2yPbx_3ySC1_xTix03 with x = 0.66 ey = 0.01 sintered at rising temperatures, and XRD pattern, showing the absence of growth of grain, and the resituación of the material in the center of the border between morphótropicas phases.
    FIG. 5 Dependence on the temperature of the dielectric permittivity for ceramic samples of Bil_x + 2yPbx_3ySC1.xTix0 3 with a) x = 0.64 ey = O, 0.01 and 0.025, b) x = 0.64.0.65 Y 0 , 66 ey = 0.01 e) x = 0.64, 0.66 Y 0.68 ey = 0.025, which show the position of the ferroelectric transition (which determines the maximum operating temperature).
    FIG. 6 Ferroelectric hysteresis cycles for ceramic samples of Bi'.x + 2yPbx_ "Sc,., Ti, O, with a) x = 0.64 ey = O, 0.01 Y 0.025, b) x = 0.64, 0.65 Y 0.66 ey = 0.01 e) x = 0.64, 0.66 Y 0.68 ey = 0.025, which show a limited increase in the mobility of the domain wall after the inclusion of the point defect under design.
    FIG. 7 Magnetoelectric voltage coefficient for Terfenol-D and Bil_x + 2yPbx.3ySC, .xTix03 with x = 0.64 ey = ° (unmodified) oy = 0.01 (chemically modified), showing a response in boosted voltage for the use of the material that includes the specific defect under design.
    EXAMPLES
    Preparation of piezoelectric ceramic samples Nanocrystalline powders of the phases were synthesized with perovskite structure of formula Bil_x + 2yPbx_3yScl.xTix03, in which
    x Y
    0.64 O, 0.01 and 0.025
    0.64 AND 0.66 0.01
    0.64, 0.66 and 0.68 0.025
    The synthesis was performed by mechanochemical activation of stoichiometric mixtures of

    820 3 (Aldrich, 99.9% pure), S ~ 03 (Aldrich, 99.9% pure), PbO (Merck, 99% pure), and Ti02
    (anatase, Cerac, 99% pure) with analytical quality. A PulveriseUe 6 Fritsch planetary mill was used. In all cases, about 10 g of the mixture of the precursor oxides was initially homogenized in a handmade agate mortar, and placed in a 250 ml tungsten carbide (WC) grinding jar with seven WC balls 2 cm in diameter and 63 g of mass each for activation at 300 rpm for 20 h.
    These conditions have been shown to provide fully crystallized perovskite monophasic powders with chemical homogeneity on a nanometric scale.
    Next, 12 mm diameter pellets were obtained by uniaxial pressing of approximately 1 g of nanocrystalline powder, which were then sintered in a closed AI2 0 3 crucible inside an oven. Temperatures of 1100 oC, 1125 oC and 1150 oC, a time at high hour temperature and heating / cooling speeds of ± 3 oC min · 'were selected.
    Note that under these conditions there is no significant loss of PbO or 8-20 3, which avoids the use of excess initial precursor or sacrificial dust; that is to say, to bury the green bodies in dust during the heat treatment. This is essential for the rigorous control of the composition and the coexistence of phases, especially necessary for the problem addressed. In this case, the inclusion of specific defects under design is achieved while maintaining full control of the structural and microstructural characteristics of the samples. Densification values above 95%, and homogeneous fine-grained microstructures with average grain sizes between 1.0 and 2.5 µm consistently have been obtained.
    Characterization of the piezoelectric ceramic samples
    The samples for characterization of the phases and the microstructure were prepared by roughing the ceramic discs to remove the surface (-100 Jlm), followed by polishing to a specular finish. Finally, a heat treatment was carried out at 600 oC for 2 h with ± 0.5 oC min · 1 to recover the damage introduced and restore the coexistence of
    Polymorphic phases and equilibrium domain configurations, which are modified by the shear stresses involved in polishing.
    The stability of the perovskite phase during sintering was controlled by diffraction

    X-ray (XRD) with a Siemens 0500 powder diffractometer and Cu Ku radiation (A = 1.5418 A). The patterns were recorded between 20 and 50 "(28) with a step of 0.05" (28) and a counting time of 5 s. Slow sweeps were also carried out; 0.02 ° step (29) and 10 s count time between 43 and 47 ° (29) through the diffraction peak 200 of the high temperature cubic phase for the analysis of the ferroelectric distortion and the evaluation of
    the percentages of phase in the border region between morphotrophic phases.
    The microstructure was studied with a scanning electron microscope with FEI Nova ™ NanoSEM 230 field emission cannon equipped with an Oxford INCA 250 energy dispersion X-ray spectrometer for chemical analysis.
    Ceramic capacitors were then prepared for electrical and electromechanical characterizations by thinning the disks up to 0.5 mm, painting Ag electrodes on the main faces, and sintering them at 700 oC.
    The electrical characterization consisted of the measurement of dielectric permittivity and ferroelectric hysteresis cycles. The dependence with the temperature of the permittivity and the dielectric losses was measured between room temperature (TA) and 550 oC with a precision LCR meter HP4284A. The measurements were carried out dynamically during a heating / cooling cycle with a speed ± 1.5 oC min · 1 at various frequencies between 100 Hz and 1 MHz. The ferroelectric hysteresis cycles were obtained at room temperature under synodal waves voltage with increasing amplitude up to 10 kV and a frequency of 0.1 Hz, obtained by combining a synthesizer / function generator (HP 33258) and a high voltage amplifier (TREK model 10/40), while charging It was measured with a load converter in its own voltage and a program for the acquisition and analysis of cycles. Subsequently, the ceramic discs were polarized for their electromechanical characterization. For this, a field of 4 kV mm-1 was applied at 100 oC for 15 min, which was maintained during cooling to 40 oC. The longitudinal piezoelectric coefficient dJJ was then measured 24 hours after the polarization stage with a Berlincourt type meter. Likewise, the transverse piezoelectric coefficient dJ1 was obtained by complex analysis of the piezoelectric radial resonances of the disks by an automatic iterative method described in
    C. Alemany et al., J Phys D: Appl Phys 1995; 28: 945. This procedure provides
    also the elastic modules S 11E Y Sl / Y the permittivity G "JJ <1 of the polarized material all in complex form and, therefore, all the mechanical, electrical and

    electromechanical
    Preparation and characterization of a magnetoelectric composite material with piezoelectric ceramic samples
    Finally, magnetoelectric composite materials were manufactured with selected Bkx + 2yPbx_3yScj_xTix03 compositions. Specifically, three-layer structures were constructed consisting of a piezoelectric ceramic disk, glued between two pieces of the Terfenol-D metal alloy (ETREMA Products Inc.) using an epoxy adhesive loaded with silver, and its magnetoelectric response was characterized_ A system consisting of the combination of two Helmholtz coils was used, designed to independently provide a static magnetic field of up to 1 kOe that magnetizes the material, and an alternating magnetic field of up to 10 Oe at 10 kHz that acts as a stimulus (Service S .L_), while measuring the voltage generated with a tunable amplifier. A geometry 31 was chosen to obtain the magnetoelectric coefficient
    transverse a31 depending on the magnetization field H, normalized to the thickness of the piezoelectric element (0.5 mm).
    Results
    The XRD patterns for ceramic materials of Bil_x + 2yPbx_3ySC1_xTixÜ3 with x = 0.64 and y = 0, 0.01 and 0.025 are shown in the Figure. No second phases were found in addition to the perovskite phase in ceramics with y = ° and 0.01, while in the material with y = 0.025 a small unidentified diffraction peak appears, suggesting that the substitution of Pb by Bi It is incomplete for this level of Bi.
    Figure 2 shows the patterns for Bil.x + 2yPbx_3ySC1_xTix03 with x = 0.64 ey = 0, 0.01 Y0.025 and improved statistics through the diffraction peak 200 of the high temperature cubic phase, together with its deconvolution using three pseudo-Voigt functions. The coexistence of rhombohedral and tetragonal phases is supposed to simplify, although it is known that the first polymorph is really monoclinic. The results clearly indicate that all materials with an increasing amount of Pb substitution by Bi are within the boundary region between morphotropic phases, although the percentage of rhombohedral phase clearly increases with the value of y, while tetragonal distortion decreases .
    Figure 3 shows scanning electron microscopy (SEM) images 10
    P201 531920
    for Bi1_x.¡.2yPbx_3ySc1_xTixü3 with x = 0.64 and y = 0, 0.01 and 0.025, that is, the three materials with an increasing amount of Bi replacing Pb. A homogeneous microstructure with an average grain size of 2.4, 1.2 and 1, 3 ~ lm is obtained for y = 0.01 and 0.025, respectively. Therefore, the substitution causes a characteristic decrease in
    5 grain size.
    To obtain a series of ceramic materials with comparable phase coexistence and an increasing concentration of the point defect under design, a new group of ceramics with x = 0.65 and y = 0.01, x = 0.66 and y = 0.01, x = 0.66 Y0.025, Y x
    10 = 0.68 and y = 0.025.
    The possibility of increasing the average grain size in chemically modified samples was also studied, so that additional sintering experiments were carried out at 1125 and 1150 ° C.
    In fact, the material with x = 0.66 and y = 0.01 showed a phase coexistence comparable to that of x = 0.64 and y = ° (reference material without inclusion of the point defect under design). Its XRD pattern is shown in Figure 4, along with that of ceramics with x = 0.64 and y = 0.01. Note the slight increase in tetragonal distortion with x. In this way, it has been possible to obtain a chemically modified material by introducing a
    no stoichiometry at site A, which remains in the center of the MPB.
    Figure S shows the dependencies with the temperature of the permittivity and the dielectric losses for the different materials 25 Bi1.x.¡.2yPbx_3ySc1_xTix0 3, while in Figure 6 the hysteresis cycles are given
    ferroelectric
    In Fig. Sta) and Sta) the curves corresponding to the initial series of materials are given with x = 0.64 and an increasing level of substitution of Pb by Bi. Note in the first figure (Fig. S (a)) the continuous decrease of the Curie temperature with the increase of y. The dielectric anomaly associated with the ferroelectric transition is observed at a temperature of 450, 395 and 375 oC for y = 0, 0.01 and 0.025, respectively. There is also a characteristic increase in permittivity and dielectric losses at room temperature with the replacement by Bi. The specific values are given in Table 1,
    35 together with the TeS.
    P201 531920
    This simultaneous increase in permittivity and losses in non-polarized ceramics could be interpreted as an enhancement of the mobility of domain walls. In fact, ferroelectric hysteresis cycles show a characteristic decrease in the coercive field, from 2.5 to 2.0 kV mm · l, when a point defect concentration of y = 0.01 is introduced at the same time as the remaining polarization Increase from 40 to 44 ~ lC cm2. In addition, this takes place despite the decrease in the average grain size, whose known effect is to increase the coercive field. However, these changes could be caused alternatively by the observed displacement of the coexistence of phases towards the rhombohedral polymorph, which has a coercive field smaller than that of the tetragonal phase.
    The results for the series of ceramic materials with increasing values of x and y = 0.01 are presented in Fig. 5 (b) Y 6 (b). Note in the first figure the continuous increase of the Curie temperature with x. The dielectric anomaly associated with the ferroelectric transition is observed at a temperature of 395, 407 and 415 oC for x = 0.64, 0.65 and 0.66, respectively. The specific values are also given in Table 1, together with the Tes. Note that the coercive field increases, so that the ceramic with x = 0.66 ey = 0.01 with the same phase coexistence as the reference material (x = 0.64 ey = O), has a similar coercive field . This indicates that the non-stoichiometry introduced at the A site does not significantly enhance the mobility of the domain wall and, in fact, does not obtain a greater remaining polarization.
    The results for the series of ceramics with increasing x and y = 0.025 are presented in Fig. 5 (c) and 6 (c). Note in the first figure the continuous increase of the Curie temperature with x. The dielectric anomaly associated with the ferroelectric transition is observed at a temperature of 375, 388 and 408 oC for x = 0.64, 0.66 and 0.68, respectively. In general, materials with y = 0.025 show a systematic decrease in permittivity and losses at room temperature with the increase of x, together with the increase in the coercive field. They also show reduced dielectric anomaly and polarization. All this strongly indicates the presence of a grain border phase formed by accumulation of specific defects, segregated from the perovskite phase that cannot be accommodated therein. The results also indicate that this phenomenon is increasingly relevant as x increases, suggesting that it is a characteristic of the tetragonal polymorph.
    Table I gives the piezoelectric coefficients of longitudinal and transverse load 12

    after polarization, as well as elastic modules.
    A first result that is worth commenting on is the significant increase in the permittivity of the materials located in the center of the MPB after polarization. The permittivity of the BiScO: unmodified high sensitivity rPbTiOJ increases from 835 to 1486, while the dielectric losses do not change. Changes in the state of mechanical stress and / or in the percentage of phases in coexistence in the MPB after polarization could be responsible for this increase in permittivity. This is a relevant question for the voltage response in detection applications and the reason why the point defect was introduced under design. In fact, the materials with phase coexistence shifted to the rhombohedral side after the inclusion of non-stoichiometry at site A; those with x = 0.64 and y = 0.01 Y0.025 nominate a comparable increase.
    It is also worth noting the significant decrease in elastic modules of polarized ceramic materials after the introduction of non-stoichiometry on site
    A. This occurs for the series of materials with x = 0.64 e and increasing, and also for the chemically modified material and located in the center of the MPB by adjusting the value of x. This last material not only has piezoelectric coefficients and elastic modules lower than those of the reference BiScOJ-PbTiOJ, but also a smaller permittivity after polarization, and a decrease in dielectric, mechanical and electromechanical losses.
    The most interesting properties are obtained for the material with x = 0.64 and y = 0.01 that has a potentiated remaining polarization with a reduced coercive field, which results in piezoelectric coefficients similar to those of the unmodified high sensitivity composition, but with a significantly lower dielectric permittivity (see Table 1). As a result, its piezoelectric voltage coefficient is much higher than that of the reference material. Specifically, the 9JJ coefficient increases from 3.3 x 10-2 to 4.8 x 10-2 V m Nl after the incorporation of non-stoichiometry at site A. This value is also greater than that of the chemically modified PZTs available. in the market with 9JJ values that vary between 2 and -2.8 x 10.2 V m N -l. Note that this potentiation of the voltage response is basically the consequence of a reduced permittivity of the polarized material, and that it is not caused by a decrease in the contribution of the domain wall, but from the contribution of the crystal, either as a consequence of the modification of the coexistence of phases or as a direct effect of the presence of specific defects on polarizability. In addition, the

    material has an elastic module also reduced; it can be assumed that the incorporation of the point defect under design causes a global increase in the rigidity of the network with a direct effect on polarizability and deformability.
    5 A new application of high sensitivity piezoelectric is in materialsmagnetoelectric compounds, in which they are combined with magnetostrictive materialsto provide magnetoelectricity as a product property. TransducersMagnetoelectric have been considered for a range of technologies such as detectorsHigh sensitivity magnetic field operating at room temperature. It has been shown
    10 that the simplest magnetoelectric voltage coefficient of the simpler piezoelectric magnetostrictive structure consisting of two layers is given by
    (1) Where d Y q are the piezoelectric and piezomagnetic coefficients of the respective phases of volume v, s are the elastic modules and & the permittivity, while the
    15 superscripts p and m refer to the piezoelectric and magnetic component, respectively. Note that the voltage response not only increases with reciprocal permittivity, but also with the inverse of the elastic coefficients.
    In Figure 7, the structural voltage magnetoelectric coefficient is compared
    20 of three layers manufactured with Terfenol-D and two BiSc03-PbTi03 materials incorporating or not the non-stoichiometry at site A: x = 0.64 and y = 0.01, and the high sensitivity reference material (x = 0, 64 ey = O). It is observed how the magnetoelectric coefficient increases from 0.2 to 1.05 V cm · 1 Oe-1 due to the selection of the piezoelectric ceramic material that includes the point defect under design.
    - <
    W
    <T
    ¡¡¡¡¡ '"~
    ,,, '(XE,) Maclado Tan 6 Not macladoTo ('<:)d33 (pC N- ')d31 (pC N- ') ,,, '(XE,) MacladosuE (x1012 m 'N-')Sl2E (x1012 m 'N-')
    y = O x = O, 648350.095450440-144 + 15;1486-1 43;13,8-O, li-3.6 + 0.2;
    y = 0.01 x = O, 649200.105395412-115 + 10;966-l15;11.7-0.5;-2.7 + 0.1;
    x = 0.65 8900.102407404
    x = 066, 1015or, 100415366-105 + 10i1368-107i11.6-0.4i-3.4 + O, 1i
    y = 0.025 x = 064,10450.127375312-70 + 8;1012-113;9.9-0.3;-2.4 + O, 1i
    x = 066, 9700.117388320
    x = O, 68 9550.101408274
    WILDEBEEST
    'i "~
    or ~ ~~
    (w
    o ~ ~ w
    m ~
    权利要求:
    Claims (9)
    [1]
    1. A piezoelectric ceramic material characterized by presenting:
    • the general formula Bi l_ ~ + 2yPb ~ _3ySC, _ ~ Ti ~ 03, in which x varies from 0.64 to 0.68 and y varies from 0.01 to 0.025;
    • a single phase located on the border between molfotropic phases with perovskite structure and R3m and tetragonal P4mm rhombohedral symmetries; Y
    • a microstructure with an average grain size between 1.0 IJm and 2.5
    ~ m.
    [2]
    2. The piezoelectric ceramic material according to claim 1, characterized in that it has a microstructure with an average grain size between 1.0 IJm and 1.5
    ~ m.
    The piezoelectric ceramic material according to any of the claims
    a 2, characterized in that it has the formula Bi'_K + 2yPbx_3ySC, _xTix0 3, in which x = 0.64 and y = 0.01.
    [4]
    4. A process for obtaining the ceramic material according to any one of claims 1 to 3, characterized in that it comprises the following steps:
    a) synthesis of a nanocrystalline powder of formula Bi l_ ~ + 2yPb ~ _3ySC, _ ~ Ti ~ 03, in which x varies from 0.64 to 0.68 and y varies from 0.01 to 0.025 by mechanochemical activation of a mixture stoichiometric of BbOJ, SC20 J, PbO and Ti02; Y
    b) sintering of the nanocrystalline powder obtained in step (a) in a temperature range of between 1100 oC and 1150 oC.
    [5]
    5. The method of obtaining according to claim 4, wherein the step
    (a) is performed for the synthesis of a nanocrystalline powder of formula Bi, .x + 2yPbx_JySc '_xTixOJ, in
    which x is 0.64 and y is 0.01. 30
    [6]
    6. A magnetoelectric composite material comprising
    • the piezoelectric ceramic material according to any one of claims 1 to 3; Y
    • a magnetostrictive material.

    [7]
    7. The magnetoelectric composite material according to claim 6, wherein the magnetostrictive material is selected from the list consisting of Terphenol-D, Metglass, and spinel oxides of formula AFe204 wherein A is Ni, Ca or a combination thereof, and a combination thereof.
    [8]
    8. The magnetoelectric composite material according to any of claims 6 or 7, wherein it is of the particulate, fiber or laminate type.
    [9]
    9. Use of the piezoelectric ceramic material according to any one of claims 1 to 3 as part of a detection device.
    [10]
    10. Use of the magnetoelectric composite material according to any of claims 6 to 8 as part of a magnetic field detection device.
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    同族专利:
    公开号 | 公开日
    ES2620690B1|2018-04-09|
    WO2017114741A1|2017-07-06|
    引用文献:
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    EP3409652A1|2017-05-31|2018-12-05|Consejo Superior de Investigaciones Cientificas |A high temperature and voltage response piezoelectric, bisco3-pbtio3 based ceramic material microstructurally engineered for enhanced mechanical performance, a procedure for obtaining said ceramic material and its use as sensing device|
    EP3409651A1|2017-05-31|2018-12-05|Consejo Superior de Investigaciones Cientificas |A high temperature and power piezoelectric, bisco3-pbtio3 based ceramic material microstructurally engineered for enhanced mechanical performance, a procedure for obtaining said ceramic material and its use as part of an ultrasound generation device or ultrasonic actuation device|
    CN108470824A|2018-03-15|2018-08-31|南方科技大学|A kind of heat safe multilayer piezoelectric ceramic actuator and its preparation method and application|
    CN109596209A|2018-12-07|2019-04-09|苏州长风航空电子有限公司|A kind of high-temperature piezoelectric vibrating sensor and piezoelectric element preparation method|
    CN111170736B|2020-02-26|2021-04-16|中国科学院上海硅酸盐研究所|Lead-based perovskite structure high-temperature piezoelectric ceramic and preparation method thereof|
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    ES201531920A|ES2620690B1|2015-12-29|2015-12-29|A HIGH TEMPERATURE PIEZOELECTRIC CERAMIC MATERIAL OF BiScO3-PbTiO3 CHEMICALLY DESIGNED TO POWER THE RESPONSE IN VOLTAGE AND PROCEDURE TO OBTAIN SUCH CERAMIC MATERIAL|ES201531920A| ES2620690B1|2015-12-29|2015-12-29|A HIGH TEMPERATURE PIEZOELECTRIC CERAMIC MATERIAL OF BiScO3-PbTiO3 CHEMICALLY DESIGNED TO POWER THE RESPONSE IN VOLTAGE AND PROCEDURE TO OBTAIN SUCH CERAMIC MATERIAL|
    PCT/EP2016/082337| WO2017114741A1|2015-12-29|2016-12-22|A high temperature piezoelectric bisco3-pbtio3 ceramic material chemically engineered for enhanced voltage response, and a procedure for obtaining said ceramic material|
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