Piezoelectric ceramic material with high dielectric constant, preparation method thereof and piezoelectric element

Abstract

The invention relates to the technical field of piezoelectric ceramic materials, in particular to a high-dielectric-constant piezoelectric ceramic material, a preparation method thereof and a piezoelectric element. The stoichiometric formula of the material is [PbaM < 1 > x < 1 > M < 2 > y < 1 > M < 3 > z < 1 >] [(Zr < n > Ti < 1-n >) bM < 4 > x < 2 > M < 5 > y < 2 > Snz < 2 >] O3, wherein the value of a ranges from 0.85 to 0.9, the value of b ranges from 0.95 to 0.99, and the value of n ranges from 0.55 to 0.65; wherein a + x1 + y1 + z1 = 1, and b + x2 + y2 + z2 = 1; wherein M1 is a monovalent IA group metal element, M2 is a divalent IIA group metal element, M3 is a trivalent lanthanide series metal element, M4 is a divalent and / or trivalent subgroup metal element or a VA group metal element, and M5 is a pentavalent VB group metal element; the piezoelectric ceramic prepared by the process has high dielectric constant and piezoelectric constant, and is suitable for buzzing devices for improving sound pressure and the like.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ceramic materials technology, specifically to a high dielectric constant piezoelectric ceramic material, its preparation method, and a piezoelectric element. Background Technology

[0002] Piezoelectric ceramics are an important component of functional ceramics and have been extensively studied since their piezoelectric effect was discovered. As a functional material with significant force-electric sensitivity, piezoelectric ceramics have been widely used in many fields such as sensors, ultrasonic transducers, micro-displacement devices, and other electronic components.

[0003] Lead zirconate titanate (PZT) ceramics, whose d 33 The ratio is approximately 300 pC / N, and PbZrO3 and PbTiO3 can form a continuous solid solution in any proportion. Traditionally, the preparation of PZT-based ceramics involves sintering at temperatures exceeding 1200°C. During sintering, significant PbO volatilization occurs, which not only causes deviations in the ceramic composition from the designed stoichiometric ratio, reducing its performance, but also pollutes the environment and harms human health.

[0004] The key to solving these problems lies in lowering the sintering temperature of PZT-based ceramics. This reduces PbO volatilization, mitigating harm to human health and the environment, while ensuring the electrical performance of the ceramics. Furthermore, as production equipment continues to evolve towards integration and miniaturization, research on electronic ceramic devices is also shifting towards multilayer structures. To achieve good performance in multilayer ceramic devices, PZT ceramic sheets and metal internal electrodes are typically sintered together. These internal electrodes often use precious metals such as Pt and Pb as raw materials, significantly increasing the production cost of ceramic devices. If a lower-cost silver-rich Ag-Pb paste is used, the sintering temperature needs to be lowered to below the paste's melting point of 1050℃; if an even lower-cost pure silver electrode is used, the sintering temperature needs to be lowered to below the pure Ag melting point of 961℃. Therefore, low-temperature sintering is crucial for reducing the environmental pollution, health impacts, and production costs of PZT-based piezoelectric ceramics.

[0005] The technical problem to be solved by this invention is how to maintain the excellent electrical properties of PZT-based ceramics at a relatively low sintering temperature. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a high-dielectric-constant piezoelectric ceramic material, its preparation method, and a piezoelectric element. The piezoelectric ceramic material prepared by the process of this invention has high dielectric and piezoelectric constants, making it suitable for use in buzzer-like devices that enhance sound pressure levels.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] A high dielectric constant piezoelectric ceramic material, with the following stoichiometric formula:

[0009] [Pb a M1 x1 M2 y1 M3 z1 ][(Zr n Ti 1-n ) b M4 x2 M5 y2 Sn z2 O3;

[0010] Where a takes values ​​in the range of 0.85-0.9, b takes values ​​in the range of 0.95-0.99, and n takes values ​​in the range of 0.55-0.6;

[0011] Where a+x1+y1+z1=1, b+x2+y2+z2=1;

[0012] M1 is a monovalent Group IA metal, M2 is a divalent Group IIA metal, M3 is a trivalent lanthanide metal, M4 is a divalent and / or trivalent transition metal or a Group VA metal, and M5 is a pentavalent Group VB metal.

[0013] Furthermore, x1 = 0.005 - 0.02, y1 = 0.03 - 0.08, z1 = 0.005 - 0.01;

[0014] x2=0.01-0.03, y2=0.005-0.015, z2=0.005-0.01.

[0015] Furthermore, M1 is selected from one or more of lithium, sodium, potassium, and rubidium; M2 is calcium and strontium with equimolar doping percentages; M3 is lanthanum; M4 is selected from one or more of manganese, iron, cobalt, nickel, and antimony; and M5 is niobium.

[0016] Preferably, M1 is selected from sodium or potassium; M4 is manganese and antimony with equimolar doping percentages.

[0017] More preferably, the stoichiometric formula of the piezoelectric ceramic material is:

[0018] [Pb a Na 0.01 Sr 0.03-0.04 Ca 0.03-0.04 La 0.03-0.04 ][(Zr 0.55-0.6 Ti 0.4-0.45 ) b Mn 0.015- 0.02 Sb 0.01 Nb 0.01 Sn0.01 ]O3.

[0019] The preparation method of the above-mentioned piezoelectric ceramic material includes the following steps:

[0020] S1. Prepare lead carbonate and various metal oxides according to the stoichiometric ratio, perform the first wet ball milling, and dry them;

[0021] S2, Pre-sintering treatment;

[0022] S3. Second wet ball milling until the median particle size of the material is less than 0.5 micrometers, then drying;

[0023] S4. Under a protective atmosphere, sintering vacuum degree ≤10pa, and pressure of 5-50MPa, rapidly heat to 700-880℃ at a rate of 80-120℃ / min for 1-3min preheating, then heat to 950-1000℃ at a rate of 5-20℃ / min and hold for 3-10min for discharge plasma sintering. After cooling, perform annealing to obtain a high dielectric constant piezoelectric ceramic material.

[0024] Furthermore, the medium used in the first and second wet ball milling processes is anhydrous ethanol;

[0025] The mass ratio of material, grinding beads, and media in the first wet ball mill is 1:1.5-2:1. The grinding beads are 3-5mm zirconium beads paired with 0.8-1mm zirconium beads, with a mass ratio of 6:4.

[0026] The mass ratio of material, grinding beads, and media in the second wet ball mill is 1:3-4:1. The grinding beads are made of 0.3-0.5mm zirconium beads and 0.05-0.2mm zirconium beads, with a mass ratio of 3:7.

[0027] The ball milling rate is 200-600 rpm, and the rotation speed of the first wet ball milling is greater than that of the first ball milling.

[0028] The time for the first and second wet ball milling processes was 6-24 hours, respectively.

[0029] Liquid nitrogen was used to control the temperature inside the ball mill jar at 15-25℃ during both ball milling processes to prevent thermal agglomeration.

[0030] Furthermore, the pre-sintering treatment involves pre-firing at 800-900℃ for 1-3 hours;

[0031] The annealing process involves heating to 700-900℃ at a rate of 1-5℃ / min and holding for 30 minutes, then heating to 950-1000℃ at a rate of 5-10℃ / min and holding for 30 minutes, followed by furnace cooling.

[0032] A third aspect of the present invention provides a piezoelectric element, comprising a single-layer piezoelectric ceramic or a multilayer piezoelectric ceramic, wherein the single-layer piezoelectric ceramic or the multilayer piezoelectric ceramic comprises a high dielectric constant piezoelectric ceramic material prepared by the preparation method described above.

[0033] Beneficial technical effects:

[0034] The piezoelectric ceramic material of this invention has the stoichiometric formula [Pb] a Na 0.01 Sr 0.03-0.04 Ca 0.03-0.04 La 0.03-0.04 ][(Zr 0.6 Ti 0.4 ) b Mn 0.015-0.02 Sb 0.01 Nb 0.01 Sn 0.01 O3, through A-site donor doping of La 3+ Nb doping with B-site donors 5+ The synergistic effect of La doping at the A site can significantly improve the piezoelectric coefficient and reduce dielectric loss. 3+ Sb doping at the B site 3+ The combination of these elements synergistically enhances the dielectric constant and piezoelectric activity, optimizing the overall performance of PZT; La doping at the A-site further improves the overall performance. 3+ With B position Nb 5+ And B position Sn 4+ The introduction of cation vacancies, combined with the synergistic effect of these three factors, further enhances the piezoelectric response. This is achieved by reducing the Pb content, promoting the enrichment of A-site dopant elements at the grain interface, thereby enhancing domain wall mobility and improving the piezoelectric response. Additionally, Ca... 2+ 、Sr 2+ The divalent ion equivalently substitutes part of the Pb at the A-site. 2+ It has a certain regulating effect on lattice distortion and improves temperature stability; Mn 3+ The doping concentration is slightly higher, which is similar to Sn. 4+ Co-doping can balance the oxygen hole concentration and reduce dielectric loss; in addition, the use of Sn and lead carbonate can reduce the sintering temperature.

[0035] In the preparation process of the piezoelectric ceramic of this invention, multi-stage ball milling with distributed grinding beads is used to achieve ultra-fine particle size of the metal oxide, and pre-firing at 800-900℃ is performed to refine the Sn particle size. 4+ After the elements are completely dissolved, rapid sintering at a lower temperature using spark plasma can alleviate the adverse effects of volatile metal elements on ceramics. Finally, annealing is performed to improve the crystal structure. The piezoelectric ceramics produced by the process of this invention have high dielectric constant and piezoelectric constant, as well as low dielectric loss. Attached Figure Description

[0036] Figure 1 The image shows the SEM morphology of the piezoelectric ceramic prepared in Example 1, where the particle length is marked as 3.649 micrometers. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specifically stated, the numerical values ​​set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] Furthermore, it should be noted that the use of terms such as "first time" and "second time" to describe ball milling is merely for the purpose of distinguishing between different ball milling steps. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention. Additionally, the expression "within the scope" is generally considered to exclude endpoint values.

[0040] Experimental methods not specified in the following examples are generally performed according to national standards; if there is no corresponding national standard, they are performed according to general standard requirements or general methods.

[0041] Example 1

[0042] A high dielectric constant piezoelectric ceramic material, with the following stoichiometric formula:

[0043] [Pb 0.89 Na 0.01 Sr 0.034 Ca 0.033 La 0.033 ][(Zr 0.55 Ti 0.45 ) 0.952 Mn 0.018 Sb 0.01 Nb 0.01 Sn 0.01 O3;

[0044] The preparation method of the above-mentioned piezoelectric ceramic material includes the following steps:

[0045] S1. Prepare the following raw materials according to stoichiometric ratios: PbCO3 0.089mol, ZrO2 0.05236mol, TiO2 0.04284mol, Na2O 0.0005mol, SrCO3 0.0034mol, CaCO3 0.0033mol, La2O3 0.00165mol, Mn2O3 0.0009mol, Nb2O3 0.0005mol, Sb2O3 0.0005mol, SnO2 0.001mol. The purity of each raw material should be ≥98%.

[0046] The first wet ball milling was performed: the above materials were added to a planetary ball mill, along with anhydrous ethanol and zirconium beads, wherein the mass ratio of materials to anhydrous ethanol to zirconium beads was 1:1.5:1. 3mm zirconium beads were used in combination with 0.8mm zirconium beads (the mass ratio of large beads to small beads was 6:4). The ball milling speed was 500 rpm, and the ball milling time was 12 hours. During the ball milling process, the liquid nitrogen temperature was controlled at 20℃. After the ball milling was completed, the materials were dried, and the zirconium beads were recovered by sieving.

[0047] S2. The material after the first ball milling is pre-sintered at 900℃ for 1 hour;

[0048] S3. The pre-calcined material is fed back into the planetary ball mill, along with anhydrous ethanol and zirconium beads. The mass ratio of material to anhydrous ethanol to zirconium beads is 1:4:1. 0.3mm zirconium beads are used in combination with 0.05mm zirconium beads (the mass ratio of large beads to small beads is 3:7). The ball milling speed is 300 rpm, and the ball milling time is 6 hours. During the ball milling process, the liquid nitrogen temperature is controlled at 20℃. After the ball milling is completed, the material is dried, and the zirconium beads are recovered by sieving.

[0049] The median particle size of the material obtained from the second wet ball milling was less than 0.5 micrometers;

[0050] S4. The powder material after the second ball milling is placed in a discharge plasma sintering furnace. Under an argon protective atmosphere, a sintering vacuum degree ≤10pa, and a pressure of 30MPa, the temperature is rapidly increased to 880℃ at a rate of 100℃ / min for preheating for 2 minutes, then increased to 980℃ at a rate of 20℃ / min and held for discharge plasma sintering for 5 minutes. After cooling, annealing is performed by increasing the temperature to 900℃ at a rate of 3℃ / min and holding for 30 minutes, then increasing the temperature to 950℃ at a rate of 5℃ / min and holding for 30 minutes. The material is then cooled with the furnace to obtain a high dielectric constant piezoelectric ceramic material.

[0051] Example 2

[0052] A high dielectric constant piezoelectric ceramic material, with the following stoichiometric formula:

[0053] [Pb 0.895 Na 0.01 Sr 0.035 Ca 0.03 La 0.03 ][(Zr 0.55 Ti 0.45 ) 0.955 Mn 0.015 Sb 0.01 Nb 0.01 Sn 0.01 O3;

[0054] The preparation method of the above-mentioned piezoelectric ceramic material includes the following steps:

[0055] S1. Prepare the following raw materials according to stoichiometric ratios: PbCO3 0.0895mol, ZrO2 0.05253mol, TiO2 0.04298mol, Na2O 0.0005mol, SrCO3 0.0035mol, CaCO3 0.003mol, La2O3 0.0015mol, Mn2O3 0.00075mol, Nb2O3 0.0005mol, Sb2O3 0.0005mol, SnO2 0.001mol. The purity of each raw material should be ≥98%.

[0056] The first wet ball milling was performed: the above materials were added to a planetary ball mill, along with anhydrous ethanol and zirconium beads, with a material-to-anhydrous ethanol-to-zirconium bead mass ratio of 1:2:1. 5mm zirconium beads were used in combination with 0.8mm zirconium beads (large bead to small bead mass ratio of 6:4). The ball milling speed was 600 rpm, and the ball milling time was 18 hours. During the ball milling process, the liquid nitrogen temperature was controlled at 20℃. After the ball milling was completed, the materials were dried, and the zirconium beads were recovered by sieving.

[0057] S2. The material after the first ball milling is pre-sintered at 880℃ for 1 hour;

[0058] S3. The pre-calcined material is fed back into the planetary ball mill, along with anhydrous ethanol and zirconium beads. The mass ratio of material to anhydrous ethanol to zirconium beads is 1:4:1. 0.5mm zirconium beads are used in combination with 0.05mm zirconium beads (the mass ratio of large beads to small beads is 3:7). The ball milling speed is 400 rpm, and the milling time is 10 hours. During the ball milling process, the liquid nitrogen temperature is controlled at 20℃. After the ball milling is completed, the material is dried, and the zirconium beads are recovered by sieving.

[0059] The median particle size of the material obtained from the second wet ball milling was less than 0.5 micrometers;

[0060] S4. The powder material after the second ball milling is placed in a discharge plasma sintering furnace. Under an argon protective atmosphere, a sintering vacuum degree ≤10pa, and a pressure of 40MPa, the temperature is rapidly increased to 880℃ at a rate of 100℃ / min for preheating for 2 minutes, then increased to 980℃ at a rate of 20℃ / min and held for discharge plasma sintering for 5 minutes. After cooling, annealing is performed by increasing the temperature to 900℃ at a rate of 3℃ / min and holding for 30 minutes, then increasing the temperature to 950℃ at a rate of 5℃ / min and holding for 30 minutes. The material is then cooled with the furnace to obtain a high dielectric constant piezoelectric ceramic material.

[0061] Example 3

[0062] A high dielectric constant piezoelectric ceramic material, with the following stoichiometric formula:

[0063] [Pb 0.88 Na 0.01 Sr 0.035 Ca 0.035 La 0.04 ][(Zr 0.55 Ti 0.45 ) 0.952 Mn 0.018 Sb 0.01 Nb 0.01 Sn 0.01 O3;

[0064] The preparation method of the above-mentioned piezoelectric ceramic material includes the following steps:

[0065] S1. Prepare the following raw materials according to stoichiometric ratios: PbCO3 0.088mol, ZrO2 0.05236mol, TiO2 0.04284mol, Na2O 0.0005mol, SrCO3 0.0035mol, CaCO3 0.0035mol, La2O3 0.002mol, Mn2O3 0.0009mol, Nb2O3 0.0005mol, Sb2O3 0.0005mol, SnO2 0.001mol. The purity of each raw material should be ≥98%.

[0066] The first wet ball milling was performed: the above materials were added to a planetary ball mill, along with anhydrous ethanol and zirconium beads, wherein the mass ratio of materials to anhydrous ethanol to zirconium beads was 1:1.5:1. 3mm zirconium beads were used in combination with 1mm zirconium beads (the mass ratio of large beads to small beads was 6:4). The ball milling speed was 600 rpm, and the ball milling time was 24 hours. During the ball milling process, the liquid nitrogen temperature was controlled at 20℃. After the ball milling was completed, the materials were dried, and the zirconium beads were recovered by sieving.

[0067] S2. The material after the first ball milling is pre-sintered at 850℃ for 1 hour;

[0068] S3. The pre-calcined material is fed back into the planetary ball mill, along with anhydrous ethanol and zirconium beads. The mass ratio of material to anhydrous ethanol to zirconium beads is 1:4:1. 0.3mm zirconium beads are used in combination with 0.1mm zirconium beads (large beads to small beads mass ratio of 3:7). The ball milling speed is 300 rpm, and the ball milling time is 12 hours. During the ball milling process, the liquid nitrogen temperature is controlled at 20℃. After the ball milling is completed, the material is dried, and the zirconium beads are recovered by sieving.

[0069] The median particle size of the material obtained from the second wet ball milling was less than 0.5 micrometers;

[0070] S4. The powder material after the second ball milling is placed in a discharge plasma sintering furnace. Under an argon protective atmosphere, a sintering vacuum degree ≤10pa, and a pressure of 25MPa, the temperature is rapidly increased to 880℃ at a rate of 100℃ / min for preheating for 2min, then increased to 980℃ at a rate of 20℃ / min and held for discharge plasma sintering for 5min. After cooling, annealing is performed by increasing the temperature to 900℃ at a rate of 3℃ / min and holding for 30min, then increasing the temperature to 950℃ at a rate of 5℃ / min and holding for 30min. The material is then cooled with the furnace to obtain a high dielectric constant piezoelectric ceramic material.

[0071] Test case

[0072] The above-mentioned material (thickness 0.5 mm) was polarized (immersed in silicone oil at room temperature, 2000 V / mm, polarization time 10 min, and left to stand for 24 hours) and its performance was tested. The results are shown in Table 1 below.

[0073] Table 1 Properties of piezoelectric ceramics

[0074]

[0075]

[0076] As shown in Table 1, the piezoelectric ceramic of the present invention has a dielectric constant of at least 5000 and a piezoelectric strain constant d. 33 At least 750 pC / N, dielectric loss less than 0.3. In the preparation process of the piezoelectric ceramic of this invention, multi-stage ball milling with distributed grinding beads is used to achieve ultra-fine metal oxide particle size. The SEM morphology of the piezoelectric ceramic of Example 1 is as follows. Figure 1 As shown, the sintered particles are relatively uniform; this invention uses synergistic doping of the PZT matrix at A-site and B-site, followed by pre-firing at 800-900℃ to induce Sn... 4+ By forming a solid solution with doped elements, and then using spark plasma sintering, rapid sintering at a lower temperature can mitigate the adverse effects of volatile metal elements on ceramics. Finally, annealing is performed to improve the crystal structure, thereby achieving functional improvements in piezoelectric ceramics, including high dielectric constant, high voltage strain constant, high mechanical quality factor, and low dielectric loss.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high dielectric constant piezoelectric ceramic material, characterized in that, Its stoichiometric formula is: [Pb a M1 x1 M2 y1 M3 z1 [(Zr n Ti 1-n ) b M4 x2 M5 y2 Sn z2 ]O3; Where a takes values ​​in the range of 0.85-0.9, b takes values ​​in the range of 0.95-0.99, and n takes values ​​in the range of 0.55-0.6; Where a+x1+y1+z1=1, b+x2+y2+z2=1; M1 is a monovalent Group IA metal, M2 is a divalent Group IIA metal, M3 is a trivalent lanthanide metal, M4 is a divalent and / or trivalent transition metal or a Group VA metal, and M5 is a pentavalent Group VB metal.

2. The high dielectric constant piezoelectric ceramic material according to claim 1, characterized in that, x1=0.005-0.02, y1=0.03-0.08, z1=0.005-0.01; x2=0.01-0.03, y2=0.005-0.015, z2=0.005-0.

01.

3. The high dielectric constant piezoelectric ceramic material according to claim 2, characterized in that, M1 is selected from one or more of lithium, sodium, potassium, and rubidium; M2 represents equimolar percentages of calcium and strontium doping; M3 is lanthanum; M4 is selected from one or more of manganese, iron, cobalt, nickel, and antimony; M5 is niobium.

4. The high dielectric constant piezoelectric ceramic material according to claim 3, characterized in that, M1 is selected from sodium or potassium; M4 is manganese and antimony with equimolar doping percentages.

5. A high dielectric constant piezoelectric ceramic material according to any one of claims 1-4, characterized in that, The stoichiometric formula of the piezoelectric ceramic material is as follows: [Pb a Na 0.01 Sr 0.03-0.04 Ca 0.03-0.04 La 0.03-0.04 [(Zr 0.55-0.6 Ti 0.4-0.45 ) b Mn 0.015- 0.02 Sb 0.01 Nb 0.01 Sn 0.01 ]O3。 6. A method for preparing a high dielectric constant piezoelectric ceramic material, characterized in that, The piezoelectric ceramic material applicable to any one of claims 1-5 is prepared by a method comprising the following steps: S1. Prepare each metal oxide according to the stoichiometric ratio, perform the first wet ball milling, and dry; S2, Pre-sintering treatment; S3. Second wet ball milling until the median particle size of the material is less than 0.5 micrometers, then drying; S4. Under a protective atmosphere, sintering vacuum degree ≤10pa, and pressure of 5-50MPa, rapidly heat to 700-880℃ at a rate of 80-120℃ / min for 1-3min preheating, then heat to 950-1000℃ at a rate of 5-20℃ / min and hold for 3-10min for discharge plasma sintering. After cooling, perform annealing to obtain a high dielectric constant piezoelectric ceramic material.

7. The method for preparing a high dielectric constant piezoelectric ceramic material according to claim 6, characterized in that, The medium used in the first and second wet ball milling processes is anhydrous ethanol. The mass ratio of material, grinding beads, and media in the first wet ball mill is 1:1.5-2:

1. The grinding beads are 3-5mm zirconium beads paired with 0.8-1mm zirconium beads, with a mass ratio of 6:

4. The mass ratio of material, grinding beads, and media in the second wet ball mill is 1:3-4:

1. The grinding beads are made of 0.3-0.5mm zirconium beads and 0.05-0.2mm zirconium beads, with a mass ratio of 3:

7. The ball milling rate is 200-600 rpm, and the rotation speed of the first wet ball milling is greater than that of the first ball milling. The time for the first and second wet ball milling processes was 6-24 hours, respectively. Liquid nitrogen was used to control the temperature inside the ball mill jar at 15-25℃ during both ball milling processes to prevent thermal agglomeration.

8. The method for preparing a high dielectric constant piezoelectric ceramic material according to claim 6, characterized in that, The pre-sintering treatment involves pre-firing at a temperature within the range of 950-1000℃ for 1-3 hours; The annealing process involves heating to 500-700℃ at a rate of 1-5℃ / min and holding for 1-3 minutes, then heating to 950-1000℃ at a rate of 5-10℃ / min and holding for 1-2 hours, followed by furnace cooling.

9. A piezoelectric element, comprising a single-layer piezoelectric ceramic or a multi-layer piezoelectric ceramic, characterized in that, The single-layer piezoelectric ceramic or the multilayer piezoelectric ceramic comprises a high dielectric constant piezoelectric ceramic material prepared by the preparation method according to any one of claims 6-8.

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