High-temperature piezoelectric ceramic and preparation method thereof, and high-temperature piezoelectric device

Abstract

The application belongs to the technical field of functional ceramics, and discloses a high-temperature piezoelectric ceramic, a preparation method thereof and a high-temperature piezoelectric device. The chemical general formula of the high-temperature piezoelectric ceramic is xBiInO3-0.2PbZrO3-(0.8-x)PbTiO3, wherein x represents a mole fraction, and the value range of x is 0.2 < x < 0.3. By introducing PbZrO3 with a perovskite structure as a third component to form a solid solution with BiInO3-PbTiO3, the tolerance factor is increased, and the key role of a structural stabilizer is played, thereby effectively solving the technical problem of the structural stability of the BI-PT system. Meanwhile, the piezoelectric ceramic has a pure perovskite phase structure, a Curie temperature greater than 550 DEG C, a piezoelectric coefficient of 56-72 pC / N, and a dielectric constant of 485-636, and is suitable for high-temperature piezoelectric devices.

Description

Technical Field

[0001] This invention belongs to the field of functional ceramics technology, specifically relating to a high-temperature piezoelectric ceramic and its preparation method, as well as a high-temperature piezoelectric device. Background Technology

[0002] Piezoelectric ceramics are a class of functional materials capable of converting mechanical energy into electrical energy, and are widely used in key electronic components such as sensors, transducers, actuators, resonators, and ultrasonic motors. Their working principle stems from the non-centrosymmetric crystal structure within the material, which generates polarization (direct piezoelectric effect) under applied mechanical stress or mechanical deformation (inverse piezoelectric effect) under applied electric field. Currently, lead zirconate titanate (PZT)-based ceramics dominate the market due to their excellent piezoelectric properties. However, the Curie temperature of traditional PZT ceramics is typically low, severely limiting their application in high-temperature fields such as aerospace engine condition monitoring, deep-well oil exploration, and advanced automotive engine fuel injection systems. To meet the demands of high-temperature applications, researchers have developed various high-temperature piezoelectric ceramic systems. Among them, bismuth-based perovskite solid solution ceramics BiScO3-PbTiO3 (BS-PT) are considered one of the most promising candidate materials. BS-PT ceramics not only exhibit excellent piezoelectric properties comparable to PZT near the quasi-isomorphic phase boundary (MPB), but also benefit from their high Curie temperature (T). C The BS-PT system, with its high operating temperature (above 450℃), has attracted considerable attention, effectively expanding the high-temperature operating window of piezoelectric devices. However, a significant disadvantage of the BS-PT system lies in the extremely high price and scarcity of its core raw material, scandium oxide (Sc2O3). This results in high manufacturing costs for BS-PT ceramics, making large-scale commercial production and application difficult. Therefore, finding a lower-cost alternative material has become an important research direction in this field.

[0003] Against this backdrop, BiInO3, which possesses similar crystal chemistry to BiScO3, has come into the research spotlight. BiInO3 also exhibits a perovskite structure, and theoretical predictions indicate that the solid solution BiInO3-PbTiO3 (BI-PT) formed by it and PbTiO3 may have a higher Curie temperature. Furthermore, since the cost of indium (In) is far lower than that of scandium (Sc), it demonstrates a significant cost advantage and application potential. However, the BI-PT system faces a major preparation challenge: due to the low tolerance factor of BiInO3, its perovskite structure itself is thermodynamically unstable at ambient pressure, making it difficult to synthesize a pure perovskite phase in the BI-PT solid solution, severely deteriorating the piezoelectric and dielectric properties of the material. Currently, obtaining high-performance BI-PT-based ceramics with a pure perovskite structure remains an unsolved technical problem in this field.

[0004] Meanwhile, the piezoelectric properties (d) of piezoelectric ceramics33 ) and Curie temperature (T C There is a certain contradiction between these two factors. Generally speaking, the higher the Curie temperature, the lower the piezoelectric activity of the material. For example, the piezoelectric coefficient of traditional PZT piezoelectric ceramics is generally higher than 300 pC / N, but the Curie temperature is generally no more than 400℃; while high-temperature piezoelectric ceramics (T...) have a higher Curie temperature. C (>500℃), such as perovskite-like layered piezoelectric ceramics, whose piezoelectric coefficient is generally lower than 30pC / N.

[0005] Therefore, there is an urgent need to develop a new piezoelectric ceramic that can increase its Curie temperature while reducing costs, so as to better adapt to high-temperature operating environments. Summary of the Invention

[0006] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a high-temperature piezoelectric ceramic, its preparation method, and a high-temperature piezoelectric device, wherein the high-temperature piezoelectric ceramic has a high Curie temperature (Ti). C With a temperature >550℃ and a piezoelectric coefficient higher than 55pC / N, it is suitable for high-temperature piezoelectric devices.

[0007] To address the aforementioned technical problems, a first aspect of the present invention provides a high-temperature piezoelectric ceramic, wherein the general chemical formula of the high-temperature piezoelectric ceramic is: xBiInO3-0.2PbZrO3-(0.8-x)PbTiO3; wherein: x represents the mole fraction, and the value of x ranges from 0.2. <x<0.3。

[0008] Specifically, although BiInO3 and BiScO3 have similar crystal chemistry properties, and indium trioxide (approximately 8 yuan / gram) has a significant cost advantage over scandium trioxide (approximately 25 yuan / gram), the tolerance factor of BiInO3 (t=0.884) is lower than that of BiScO3 (t=0.907). Therefore, it is difficult to synthesize a pure perovskite structure in BI-PT solid solutions, thus failing to obtain good piezoelectric and dielectric properties. To address this, this invention proposes a bismuth indium-lead zirconate-lead titanate piezoelectric ceramic. Lead zirconate (PbZrO3) with a perovskite structure is introduced as a third component to form a solid solution with BiInO3-PbTiO3. The Zr content in the PbZrO3 solid solution... 4+ Ions can effectively improve the tolerance factor and thermodynamically promote the formation and stability of the perovskite phase, playing a key role as a "structural stabilizer". This solves the technical problem of the difficulty in stabilizing the perovskite phase in the BI-PT system and yields high-temperature piezoelectric ceramics with low raw material costs.

[0009] In some embodiments of the present invention, the value range of x is: 0.21≤x≤0.24; for example, x=0.21, x=0.22, x=0.23, or x=0.24, etc., including but not limited to the listed values; at the same time, other unlisted values ​​within the range also apply. In the bismuth indium-lead zirconate-lead titanate piezoelectric ceramic of the present invention, the bismuth indium content is high, and it is one of the main components, rather than a trace element modification, thus having a good structural stabilizing effect.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned high-temperature piezoelectric ceramic, comprising the following steps:

[0011] (1) Bi2O3, In2O3, PbO, ZrO2 and TiO2 are mixed according to the stoichiometric ratio in the general chemical formula to obtain a mixed raw material; then the mixed raw material is pre-calcined to obtain a pre-calcined powder;

[0012] (2) An organic binder is added to the pre-fired powder, and the mixture is pressed into shape to obtain a ceramic green body;

[0013] (3) Remove the binder from the ceramic green body, remove the organic binder, and sinter to obtain a ceramic block;

[0014] (4) The surface of the ceramic block is polished, silvered and polarized in sequence to obtain the high temperature piezoelectric ceramic.

[0015] Specifically, in the preparation of the high-temperature piezoelectric ceramic of the present invention, each raw material is first pre-fired, and the raw materials are reacted through solid-state sintering to obtain a stable pre-fired powder with a perovskite structure, so as to reduce the generation of impurity phases in the later sintering process and lay the foundation for the subsequent pure perovskite structure bismuth indium-lead zirconate-lead titanate piezoelectric ceramic.

[0016] In some embodiments of the present invention, in step (1), the pre-firing temperature is 850-900°C and the pre-firing time is 2-4 hours.

[0017] In some embodiments of the present invention, step (1) further includes ball milling, drying and grinding of the mixed raw materials before the pre-calcination.

[0018] In some embodiments of the present invention, step (2) further includes a step of ball milling, drying and grinding the pre-calcined powder with added organic binder before pressing and molding.

[0019] In some embodiments of the present invention, the ball milling medium is anhydrous ethanol or water.

[0020] In some embodiments of the present invention, the mass ratio of the material to the medium in the ball mill is 1:(1-2).

[0021] In some embodiments of the present invention, the rotational speed of the ball mill is 200-300 r / min.

[0022] In some embodiments of the present invention, the ball milling time is 12-24 hours.

[0023] In some embodiments of the present invention, in step (2), the organic adhesive is an acrylic latex adhesive, such as a Rhoplex solution.

[0024] In some embodiments of the present invention, in step (2), the amount of organic binder added is 2-4 wt% of the pre-calcined powder.

[0025] In some embodiments of the present invention, in step (3), the temperature of the glue discharge is 550-650°C.

[0026] In some embodiments of the present invention, in step (3), the heating rate of the adhesive removal is 1-2℃ / min.

[0027] In some embodiments of the present invention, in step (3), the glue removal time is 1-2 hours.

[0028] In some embodiments of the present invention, in step (3), the sintering temperature is 1050-1100°C.

[0029] In some embodiments of the present invention, in step (3), the heating rate of the sintering is 1-2℃ / min.

[0030] In some embodiments of the present invention, the sintering time in step (3) is 2-4 hours.

[0031] In some embodiments of the present invention, in step (4), the polarization process conditions are: temperature of 110-130℃, electric field of 40-60kV / cm, and time of 5-10min.

[0032] A third aspect of the present invention provides a high-temperature piezoelectric device, wherein the material for preparing the high-temperature piezoelectric device includes the above-mentioned high-temperature piezoelectric ceramic.

[0033] In some embodiments of the present invention, the high-temperature piezoelectric device is selected from high-temperature piezoelectric detectors, high-temperature sensors, high-temperature transducers, or high-temperature actuators. The high-temperature piezoelectric ceramic of the present invention has a high Curie temperature, which offers significant advantages over conventional piezoelectric ceramics in the application of high-temperature piezoelectric devices.

[0034] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0035] (1) In this invention, PbZrO3 with a perovskite structure is introduced as a third component to form a solid solution together with BiInO3-PbTiO3. The Zr in the solid solution PbZrO3 4+ Ions can effectively improve the tolerance factor, thermodynamically promoting the formation and stabilization of the perovskite phase, playing a key role as a "structural stabilizer," thus solving the technical problem of structural stability in the BI-PT system. Meanwhile, the bismuth indium-lead zirconate-lead titanate piezoelectric ceramic of this invention has a pure perovskite phase structure, overcoming the problem of impurity phases. Its Curie temperature is greater than 550℃, even reaching 557℃; its piezoelectric coefficient is 56-72 pC / N, and its dielectric constant is 485-636, making it suitable for high-temperature piezoelectric devices.

[0036] (2) Compared with the traditional BS-PT system high-temperature piezoelectric ceramics, the bismuth indium-lead zirconate-lead titanate piezoelectric ceramics of the present invention not only have a significant cost advantage, but also have similar Curie temperatures, and have good market application value and competitiveness. Attached Figure Description

[0037] Figure 1 This is the XRD pattern of the high-temperature piezoelectric ceramic prepared in Example 1;

[0038] Figure 2 This is the dielectric temperature spectrum of the high-temperature piezoelectric ceramic prepared in Example 1;

[0039] Figure 3 This is the XRD pattern of the piezoelectric ceramic prepared in Comparative Example 1. Detailed Implementation

[0040] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0041] Example 1

[0042] A high-temperature piezoelectric ceramic has the chemical formula: 0.24BiInO3-0.2PbZrO3-0.56PbTiO3. The preparation method of this high-temperature piezoelectric ceramic includes the following steps:

[0043] (1) Weigh Bi2O3, In2O3, PbO, ZrO2 and TiO2 raw materials according to the stoichiometric ratio of chemical formula 0.24BiInO3-0.2PbZrO3-0.56PbTiO3, and then put each raw material into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of material to anhydrous ethanol is 1:1). Dry them thoroughly in an oven at 100℃. Then grind them evenly in an agate mortar and pestle. Finally, put them into an alumina crucible and pre-calcine them at 850℃ for 4 hours to obtain pre-calcined powder.

[0044] (2) Add Rhoplex binder to the pre-fired powder obtained in step (1) (the amount of binder added is 4wt% of the mass of the pre-fired powder), and then put it into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of the material to anhydrous ethanol is 1:1), then put it into a 100℃ oven to dry, and finally put it into an agate mortar for grinding, sieve it, and press it into shape to obtain ceramic green body.

[0045] (3) Place the ceramic green body obtained in step (2) into a box furnace, heat it to 600°C at a rate of 2°C / min and keep it at that temperature for 2 hours to remove the adhesive; then heat it to 1100°C at a rate of 2°C / min and keep it at that temperature for 4 hours. After cooling down naturally, the ceramic block is obtained.

[0046] (4) Polish the ceramic block obtained in step (3), then apply silver electrodes to both sides of the polished ceramic block, and apply an electric field of 60kV / cm at 120℃ for 5min to polarize it, thus obtaining the 0.24BiInO3-0.2PbZrO3-0.56PbTiO3 high temperature piezoelectric ceramic of this embodiment.

[0047] Example 2

[0048] A high-temperature piezoelectric ceramic has the chemical formula: 0.23BiInO3-0.2PbZrO3-0.57PbTiO3. The preparation method of this high-temperature piezoelectric ceramic includes the following steps:

[0049] (1) Weigh Bi2O3, In2O3, PbO, ZrO2 and TiO2 raw materials according to the stoichiometric ratio of chemical formula 0.23BiInO3-0.2PbZrO3-0.57PbTiO3, and then put each raw material into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of material to anhydrous ethanol is 1:1). Dry them thoroughly in an oven at 100℃. Then grind them evenly in an agate mortar and pestle. Finally, put them into an alumina crucible and pre-calcine them at 900℃ for 4 hours to obtain pre-calcined powder.

[0050] (2) Add Rhoplex binder to the pre-fired powder obtained in step (1) (the amount of binder added is 4wt% of the mass of the pre-fired powder), and then put it into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of the material to anhydrous ethanol is 1:1), then put it into a 100℃ oven to dry, and finally put it into an agate mortar for grinding, sieve it, and press it into shape to obtain ceramic green body.

[0051] (3) Place the ceramic green body obtained in step (2) into a box furnace, heat it to 550°C at a rate of 1°C / min and keep it at that temperature for 2 hours to remove the adhesive; then heat it to 1100°C at a rate of 1°C / min and keep it at that temperature for 4 hours. After cooling down naturally, the ceramic block is obtained.

[0052] (4) Polish the ceramic block obtained in step (3), then apply silver electrodes to both sides of the polished ceramic block, and apply an electric field of 60kV / cm at 120℃ for 5min to polarize it, thus obtaining the 0.23BiInO3-0.2PbZrO3-0.57PbTiO3 high temperature piezoelectric ceramic of this embodiment.

[0053] Example 3

[0054] A high-temperature piezoelectric ceramic has the chemical formula: 0.22BiInO3-0.2PbZrO3-0.58PbTiO3. The preparation method of this high-temperature piezoelectric ceramic includes the following steps:

[0055] (1) Weigh Bi2O3, In2O3, PbO, ZrO2 and TiO2 raw materials according to the stoichiometric ratio of chemical formula 0.22BiInO3-0.2PbZrO3-0.58PbTiO3, and then put each raw material into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of material to anhydrous ethanol is 1:1). Dry them thoroughly in an oven at 100℃. Then grind them evenly in an agate mortar, and finally put them into an alumina crucible and pre-calcine them at 900℃ for 2 hours to obtain pre-calcined powder.

[0056] (2) Add Rhoplex binder to the pre-fired powder obtained in step (1) (the amount of binder added is 4wt% of the mass of the pre-fired powder), and then put it into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of the material to anhydrous ethanol is 1:1), then put it into a 100℃ oven to dry, and finally put it into an agate mortar for grinding, sieve it, and press it into shape to obtain ceramic green body.

[0057] (3) Place the ceramic green body obtained in step (2) into a box furnace, heat it to 550°C at a rate of 2°C / min and keep it at that temperature for 2 hours to remove the adhesive; then heat it to 1100°C at a rate of 2°C / min and keep it at that temperature for 2 hours. After cooling down naturally, the ceramic block is obtained.

[0058] (4) Polish the ceramic block obtained in step (3), then apply silver electrodes to both sides of the polished ceramic block, and apply an electric field of 40kV / cm at 120℃ for 10min to polarize it, thus obtaining the 0.22BiInO3-0.2PbZrO3-0.58PbTiO3 high temperature piezoelectric ceramic of this embodiment.

[0059] Example 4

[0060] A high-temperature piezoelectric ceramic has the chemical formula: 0.21BiInO3-0.2PbZrO3-0.59PbTiO3. The preparation method of this high-temperature piezoelectric ceramic includes the following steps:

[0061] (1) Weigh Bi2O3, In2O3, PbO, ZrO2 and TiO2 raw materials according to the stoichiometric ratio of chemical formula 0.21BiInO3-0.2PbZrO3-0.59PbTiO3, and then put each raw material into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of material to anhydrous ethanol is 1:1). Dry them thoroughly in an oven at 100℃. Then grind them evenly in an agate mortar, and finally put them into an alumina crucible and pre-calcine them at 850℃ for 4 hours to obtain pre-calcined powder.

[0062] (2) Add Rhoplex binder to the pre-fired powder obtained in step (1) (the amount of binder added is 4wt% of the mass of the pre-fired powder), and then put it into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of the material to anhydrous ethanol is 1:1), then put it into a 100℃ oven to dry, and finally put it into an agate mortar for grinding, sieve it, and press it into shape to obtain ceramic green body.

[0063] (3) Place the ceramic green body obtained in step (2) into a box furnace, heat it to 600°C at a rate of 2°C / min and keep it at that temperature for 2 hours to remove the adhesive; then heat it to 1050°C at a rate of 2°C / min and keep it at that temperature for 4 hours. After cooling down naturally, the ceramic block is obtained.

[0064] (4) Polish the ceramic block obtained in step (3), then apply silver electrodes to both sides of the polished ceramic block, and apply an electric field of 60kV / cm at 120℃ for 10min to polarize it, thus obtaining the 0.21BiInO3-0.2PbZrO3-0.59PbTiO3 high temperature piezoelectric ceramic of this embodiment.

[0065] Comparative Example 1

[0066] A piezoelectric ceramic with the chemical formula 0.44BiInO3-0.56PbTiO3. The preparation method of this piezoelectric ceramic includes the following steps:

[0067] (1) Weigh Bi2O3, In2O3, PbO and TiO2 raw materials according to the stoichiometric ratio of chemical formula 0.44BiInO3-0.56PbTiO3, and then put each raw material into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of material to anhydrous ethanol is 1:1). Dry them thoroughly in an oven at 100℃. Then grind them evenly in an agate mortar, and finally put them into an alumina crucible and pre-calcine them at 850℃ for 4 hours to obtain pre-calcined powder.

[0068] (2) Add Rhoplex binder to the pre-fired powder obtained in step (1) (the amount of binder added is 4wt% of the mass of the pre-fired powder), and then put it into a ball mill jar for ball milling for 12 hours (the ball milling medium is anhydrous ethanol, and the mass ratio of the material to anhydrous ethanol is 1:1), then put it into a 100℃ oven to dry, and finally put it into an agate mortar for grinding, sieve it, and press it into shape to obtain ceramic green body.

[0069] (3) Place the ceramic green body obtained in step (2) into a box furnace, heat it to 600°C at a rate of 2°C / min and keep it at that temperature for 2 hours to remove the adhesive; then heat it to 1100°C at a rate of 2°C / min and keep it at that temperature for 4 hours. After cooling down naturally, the ceramic block is obtained.

[0070] (4) The ceramic block obtained in step (3) is polished and then silver electrodes are applied to both sides of the polished ceramic block. An electric field of 60 kV / cm is applied at 120°C and polarized for 5 min to obtain the 0.44BiInO3-0.56PbTiO3 piezoelectric ceramic of this comparative example.

[0071] Performance testing

[0072] 1. XRD Analysis

[0073] Figure 1 and Figure 3 The XRD patterns of the piezoelectric ceramics prepared in Example 1 and Comparative Example 1 are shown below. Figure 1 It can be seen that the piezoelectric ceramic has a single perovskite structure and no other impurity phases are generated; from Figure 3 It can be seen that the crystal structure of this piezoelectric ceramic contains a large number of impurity phases.

[0074] 2. Curie temperature

[0075] Figure 2The dielectric temperature spectrum of the high-temperature piezoelectric ceramic prepared in Example 1 is shown below. Figure 2 It can be seen that the Curie temperature of this piezoelectric ceramic is 557℃.

[0076] 3. Electrical properties

[0077] The dielectric constant and piezoelectric coefficient of the piezoelectric ceramic samples prepared in Examples 1-4 and Comparative Example 1 were tested, and the results are shown in Table 1.

[0078] Table 1:

[0079]

[0080] As shown in Table 1, the bismuth indium-lead zirconate-lead titanate piezoelectric ceramics prepared in Examples 1-4 of this invention exhibit good electrical properties, and their piezoelectric coefficients (d...) are... 33 The piezoelectric properties of the material are within the range of 56-72 pC / N, and the dielectric constant is between 485-636, indicating that the material possesses usable piezoelectric and dielectric properties. In contrast, the piezoelectric ceramic prepared in Comparative Example 1 has an incomplete structure and reduced insulation performance due to the formation of a large number of impurity phases during sintering. It cannot withstand high electric fields during polarization treatment, exhibiting phenomena such as the electric field failing to rise normally (i.e., premature breakdown or excessive leakage current). Therefore, it fails to achieve effective polarization and ultimately does not possess measurable piezoelectric properties.

[0081] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A high-temperature piezoelectric ceramic, characterized in that, The chemical formula of the high-temperature piezoelectric ceramic is: xBiInO3-0.2PbZrO3-(0.8-x)PbTiO3; where x represents the mole fraction and the value of x is 0.21≤x≤0.24; the high-temperature piezoelectric ceramic has a single perovskite structure.

2. A method for preparing high-temperature piezoelectric ceramic as described in claim 1, characterized in that, Includes the following steps: (1) Bi2O3, In2O3, PbO, ZrO2 and TiO2 are mixed according to the stoichiometric ratio in the general chemical formula to obtain a mixed raw material; then the mixed raw material is pre-calcined to obtain a pre-calcined powder; the pre-calcination temperature is 850-900℃ and the pre-calcination time is 2-4 hours; (2) An organic binder is added to the pre-fired powder, and the mixture is pressed into shape to obtain a ceramic green body; (3) Remove the binder from the ceramic green body, remove the organic binder, and sinter to obtain a ceramic block; (4) The surface of the ceramic block is polished, silvered and polarized in sequence to obtain the high temperature piezoelectric ceramic.

3. The method for preparing high-temperature piezoelectric ceramics according to claim 2, characterized in that, In step (1), before the pre-calcination, the mixed raw materials are further subjected to ball milling, drying and grinding.

4. The method for preparing high-temperature piezoelectric ceramics according to claim 2, characterized in that, In step (2), the organic binder is an acrylic latex binder, and the amount of organic binder added is 2-4 wt% of the pre-fired powder.

5. The method for preparing high-temperature piezoelectric ceramics according to claim 2, characterized in that, In step (3), the temperature of the glue removal is 550-650℃, and the glue removal time is 1-2 hours.

6. The method for preparing high-temperature piezoelectric ceramics according to claim 2, characterized in that, In step (3), the sintering temperature is 1050-1100℃ and the sintering time is 2-4 hours.

7. The method for preparing high-temperature piezoelectric ceramics according to claim 2, characterized in that, In step (4), the polarization process conditions are: temperature of 110-130℃, electric field of 40-60kV / cm, and time of 5-10min.

8. A high-temperature piezoelectric device, characterized in that, The material used to prepare the high-temperature piezoelectric device includes the high-temperature piezoelectric ceramic described in claim 1.

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