CN110128126B - Bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic and preparation method thereof - Google Patents

Abstract

The invention discloses a bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic and a preparation method thereof, and the composition general formula is as follows: xBiFeO₃‑yBaTiO₃‑zBi(Ti_0.5Zn_0.5)O₃+tBiAlO₃+mP+nMnCO₃+2.5％Bi₂O₃Wherein x, y, z, t, m and n represent mole fraction, x is more than or equal to 0.6 and less than or equal to 0.8, y is more than or equal to 0.15 and less than or equal to 0.3, z is more than or equal to 0.05 and less than or equal to 0.15, and 0<t≤0.10,0<m≤0.1,0<n is less than or equal to 0.1, 2.5 mol percent of Bi₂O₃In order to compensate the volatilization of Bi element in the sintering process, and the Bi element is used as a sintering aid; p is Ba (W)_0.5Cu_0.5)O₃、CuO、Li₂CO₃One or more ofA combination of sintering aids; the preparation method comprises the working procedures of proportioning according to the general formula of composition, ball milling, forming, binder removal, sintering and the like, and the prepared material has the Curie temperature reaching Tc-596 ℃ and the depolarization temperature reaching T_dThe high-temperature lead-free piezoelectric ceramic is 580 ℃ and has the highest piezoelectric constant of 137pC/N, and is expected to be applied to the high-temperature fields of aerospace, nuclear power, oil exploration and the like.

Description

Bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic and preparation method thereof

Technical Field

The invention relates to a lead-free piezoelectric ceramic material applicable to the field of high temperature, in particular to a bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic and a preparation method thereof.

Background

The high-temperature piezoelectric ceramic is widely applied to the fields of aerospace, nuclear energy, oil exploration and the like as a vibration sensor, and BiFeO₃Has high Curie temperature (830 ℃) and large remanent polarization, and theoretical calculation shows that BiFeO₃Has good piezoelectric performance, but BiFeO₃The single synthesis is difficult, and Bi-rich phase Bi is easily generated in the synthesis process₂₄Fe₂O₃₉And Fe-rich phase Bi₂Fe₄O₉And so on. By introducing BaTiO into the system₃Form BiFeO therewith₃-BaTiO₃Solid solution, can effectively inhibit the generation of miscellaneous items, and can be added with MnO₂D can be obtained by suppressing the generation of oxygen vacancies by the equal elements to improve the resistivity₃₃>170pC/N BFBT ceramic, but BaTiO₃The introduction of (2) causes the sintering temperature to be higher, resulting in the increase of dielectric loss, and BaTiO₃The Curie temperature of the alloy is only 120 ℃, so that BiFeO is obtained₃-BaTiO₃The temperature stability of the system is reduced, and the depolarization temperature can only be kept at T_d<The range of 500 ℃. Bi (Ti)_0.5Zn_0.5)O₃Is a tetragonal phase perovskite structure compound with high Curie temperature, and is mixed with BiFeO₃Can form solid solution, and the solid solution of the two is calculated according to theory and is in monoclinic phase 0.4Bi(Ti_0.5Zn_0.5)O₃-0.6BiFeO₃T at composition_C1227 ℃ can be reached. But Bi (Ti)_0.5Zn_0.5)O₃The synthesis of (A) is difficult, and the synthesis of (B) is required under high temperature and high pressure conditions, because of the easy generation of miscellaneous items. BiAlO₃Is a tripartite perovskite structure compound, has a Curie temperature of more than 550 ℃, does not have any phase change from room temperature to 550 ℃, and has very high temperature stability, but BiAlO₃The synthesis of (2) is also difficult and requires synthesis at high temperature and high pressure.

Disclosure of Invention

The invention aims to provide bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic and a preparation method thereof_dThe temperature is 580 ℃, the piezoelectric constant reaches 137pC/N, and the system ceramic is expected to be applied to the field of high-temperature piezoelectric vibration sensors for aerospace and the like.

The technical scheme for realizing the invention is as follows:

the high-temperature lead-free piezoelectric ceramic comprises bismuth ferrite, barium titanate, zinc bismuth titanate and bismuth aluminate, and has the following composition general formula: xBiFeO₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃-tBiAlO₃+mP+nMnCO₃+0.025Bi₂O₃Wherein x, y, z, t, m and n represent mole fractions, and P is Ba (W)_0.5Cu_0.5)O₃、CuO、Li₂CO₃Wherein x is more than or equal to 0.6 and less than or equal to 0.8, y is more than or equal to 0.15 and less than or equal to 0.3, z is more than or equal to 0.05 and less than or equal to 0.15, and 0 is combined with one or two sintering aids<t≤0.10,0<m≤0.1,0<n≤0.1。

The preparation method of the bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic comprises the following steps:

(1) to analytically pure TiO₂、BaCO₃As a raw material, according to BaTiO₃The mixed powder is ball milled for 24 hours by taking absolute ethyl alcohol as a medium, dried in an oven at 100 ℃/12 hours, sieved by a 200-mesh sieve, put into a high-alumina crucible, compacted and covered, and then put into a muffle furnace for heat preservation at 980 DEG CSynthesizing for 6 hours, cooling to below 200 ℃, and taking out for later use;

(2) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、TiO₂、W₂O₃、ZnO、Li₂CO₃CuO as raw material, according to BaTiO₃-aBi(Ti_0.5Zn_0.5)O₃Mixing at a ratio of + cP, wherein P is sintering aid Ba (W)_0.5Cu_0.5)O₃、Li₂CO₃One or a combination of two kinds of sintering aids of CuO, and 0<a≤0.60,0<c is less than or equal to 0.1, ball milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the mixed powder at the temperature of 100 ℃/12 hours, drying the mixed powder in an oven, sieving the dried mixed powder by a 200-mesh sieve, putting the dried mixed powder into a high-alumina crucible to be compacted and covered, then putting the crucible into a muffle furnace to keep the temperature of 900-950 ℃ for 4 hours for synthesis, cooling the mixture to below 200 ℃, and taking out the cooled mixture for later use;

(3) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、Al₂O₃、Li₂CO₃CuO as raw material, according to BaTiO₃-bBiAlO₃Mixing at a ratio of + dP, wherein P is a sintering aid Ba (W)_0.5Cu_0.5)O₃、Li₂CO₃One or a combination of two kinds of sintering aids of CuO, and 0<b≤0.60,0<d is less than or equal to 0.1, ball milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the mixed powder at the temperature of 100 ℃/12 hours, drying the mixed powder in an oven, sieving the dried mixed powder by a 200-mesh sieve, putting the sieved mixed powder into a high-alumina crucible, compacting and covering the crucible, putting the crucible into a muffle furnace, keeping the temperature of 800-850 ℃ for 4 hours, synthesizing the mixture, cooling the mixture to below 200 ℃, and taking the cooled mixture out for later use;

(4) adding Bi₂O₃、Fe₂O₃With the BaTiO synthesized in the step (2)₃-aBi(Ti_0.5Zn_0.5)O₃+ cP and BaTiO synthesized in step (3)₃-bBiAlO₃+ d P according to xBiFeO₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃-tBiAlO₃+mP+nMnCO₃+2.5％Bi₂O₃Mixing materials, wherein x is more than or equal to 0.6 and less than or equal to 0.8, y is more than or equal to 0.15 and less than or equal to 0.30, z is more than or equal to 0.05 and less than or equal to 0.15, and z is more than or equal to 0.05 and less than or equal to 0.15<t≤0.10,0<m≤0.1,0<n≤01; wherein 2.5 mol% of Bi₂O₃In order to compensate the volatilization of Bi element in the sintering process and serve as a sintering aid to promote the sintering process, the mixed powder is ball-milled for 24 hours by taking absolute ethyl alcohol as a medium, dried in an oven at 100 ℃/12 hours, sieved by a 200-mesh sieve, put into a high-alumina crucible to be compacted and capped, and then put into a closed tube furnace to be synthesized into xBiFeO by introducing pure oxygen at the heating rate of 250 ℃/h to 780 ℃/4h₃-yBaTiO₃-zBiAlO₃+tBi(Ti_0.5Zn_0.5)O₃+mP+nMnCO₃Preserving heat for 4 hours, cooling to below 200 ℃, and taking out for later use;

(5) the xBiFeO synthesized in the step (4) is₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃-tBiAlO₃+mP+nMnCO₃+0.025Bi₂O₃Carrying out secondary ball milling on the powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the powder, drying the powder, and sieving the powder by a 200-mesh sieve;

(6) adding the sieved powder into 5% PVA solution with mass percentage concentration for granulation, and performing compression molding in a steel die under 100MPa, wherein the inner diameter of the die is 1 cm;

(7) placing the molded plain sheet into a muffle furnace, slowly heating to 600 ℃ at the heating rate of 60 ℃/h, and keeping the temperature for 24 hours to discharge glue; then rapidly heating to 960-1000 ℃ at the heating rate of 20 ℃/min, preserving the heat for 120 minutes, and cooling to room temperature along with the furnace;

(8) polishing the sintered sample into a sheet with two smooth surfaces and a thickness of 1mm, coating a silver electrode, and burning silver at 650 ℃/30 minutes for later use;

(9) polarizing the piezoelectric ceramic plate coated with the silver electrode in silicone oil, wherein the polarizing electric field is 6000V/mm, the polarizing temperature is 150 ℃, the time is 30 minutes, and then cooling is carried out, and the electric field is kept to be cooled to the room temperature.

In order to obtain compact BiFeO₃-BaTiO₃-Bi(Ti_0.5Zn_0.5)O₃-BiAlO₃Solid solution ceramics, adopting BaTiO synthesized first₃The main crystal phase is then used as an inducer to mix BaTiO₃And Bi₂O₃、Al₂O₃Mixing well with Li₂CO₃、CuO、Ba(W_0.5Cu_0.5)O₃And the like are used as sintering aids and are calcined to obtain BaTiO₃-BiAlO₃The perovskite structure solid solution of (a); BaTiO is obtained by the same method₃-Bi(Ti_0.5Zn_0.5)O₃Perovskite structure solid solution of (A), and finally adding Bi₂O₃、Fe₂O₃With BaTiO₃-BiAlO₃、BaTiO₃-Bi(Ti_0.5Zn_0.5)O₃Compounding to form BiFeO₃-BaTiO₃-Bi(Ti_0.5Zn_0.5)O₃-BiAlO₃Quaternary solid solutions. By adopting the technical route, the BaTiO is fully utilized₃The structure induction effect of (1) can effectively avoid synthesizing BiAlO₃And Bi (Ti)_0.5Zn_0.5)O₃The required high temperature and high pressure condition and the generation of inhibition miscellaneous items, BiFeO with high Curie temperature₃With BaTiO₃-BiAlO₃And BaTiO₃-Bi(Ti_0.5Zn_0.5)O₃Form solid solution and reduce BaTiO₃The proportion content of the components in the whole system can be realized by BiAlO₃Trigonal structure of (1) and Bi (Ti)_0.5Zn_0.5)O₃The tetragonal phase structure of the system regulates and controls the phase structure of the system to obtain BiFeO with high piezoelectric property, high Curie temperature and high temperature stability₃-BaTiO₃-Bi(Ti_0.5Zn_0.5)O₃-BiAlO₃A quaternary leadless piezoelectric ceramic.

The invention has the positive effects that:

the invention adopts Bi (Ti) with high Curie temperature_0.5Zn_0.5)O₃、BiAlO₃With BiFeO₃-BaTiO₃And compounding to form a solid solution so as to obtain the piezoelectric ceramic with high Curie temperature and higher temperature stability. In which BaTiO is used₃Are respectively reacted with Bi₂O₃、TiO₂、ZnO、Li₂CO₃BaTiO synthesized by CuO₃-aBi(Ti_0.5Zn_0.5)O₃+ cP and BaTiO₃And Bi₂O₃、Al₂O₃、Li₂CO₃BaTiO synthesized by CuO₃-bBiAlO₃+ dP, make full use of BaTiO₃The perovskite structure of (A) is stable and Bi (Ti)_0.5Zn_0.5)O₃And BiAlO₃The perovskite structure of (1) and the addition of a sintering aid to promote the synthesis of a main crystal phase and suppress the generation of a heterogeneous phase. xBiFeO prepared by adopting the technology₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃-tBiAlO₃The Curie temperature of the high-temperature piezoelectric ceramic can reach Tc 596 ℃, and the depolarization temperature reaches T_d580 deg.C, and a piezoelectric constant up to d is obtained₃₃The piezoelectric performance of 137pC/N is not known from the literature published at present₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃-tBiAlO₃The system has reports and related patents for obtaining such high pressure performance and temperature stability, so the technology has great breakthrough and innovation from the technical point of view and has practicability.

Detailed Description

The contents of the present invention will be further clarified by the following examples, which are not intended to limit the present invention.

Example 1:

the components: 0.70BiFeO₃-0.20BaTiO₃-0.05Bi(Ti_0.5Zn_0.5)O₃-0.05BiAlO₃+0.01Li₂CO₃+0.01MnCO₃+0.025Bi₂O₃The preparation method comprises the following steps:

(1) to analytically pure TiO₂、BaCO₃As a raw material, according to BaTiO₃The preparation method comprises the following steps of proportioning, ball-milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, drying the mixed powder in an oven at 100 ℃/12 hours, sieving the dried mixed powder by a 200-mesh sieve, putting the dried mixed powder into a high-aluminum crucible, compacting and covering the crucible, putting the crucible into a muffle furnace, keeping the temperature of the muffle furnace at 980 ℃ for 6 hours, synthesizing, cooling the muffle furnace to below 200 ℃, and taking the cooled muffle furnace out for later use;

(2) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、TiO₂、ZnO、Li₂CO₃As raw material, according to1.0 of BaTiO₃-0.5Bi(Ti_0.5Zn_0.5)O₃+0.05Li₂CO₃The preparation method comprises the following steps of proportioning, ball-milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the mixed powder, drying the mixed powder in an oven at the temperature of 100 ℃/12 hours, sieving the dried mixed powder by a 200-mesh sieve, putting the dried mixed powder into a high-alumina crucible, compacting and covering the crucible, putting the crucible into a muffle furnace, keeping the temperature at 920 ℃ for 4 hours, synthesizing, cooling the mixture to below 200 ℃, and taking out the mixture for later use;

(3) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、Al₂O₃、Li₂CO₃As raw material, according to 1.0BaTiO₃-0.5BiAlO₃+0.05Li₂CO₃The preparation method comprises the following steps of proportioning, ball-milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the mixed powder, drying the mixed powder in an oven at the temperature of 100 ℃/12 hours, sieving the dried mixed powder by a 200-mesh sieve, putting the dried mixed powder into a high-alumina crucible, compacting and covering the crucible, putting the crucible into a muffle furnace, keeping the temperature for 4 hours at the temperature of 850 ℃, synthesizing, cooling the mixture to below 200 ℃, and taking out the mixture for later use;

(4) adding Bi₂O₃、Fe₂O₃With the 1.0BaTiO synthesized in the step (2)₃-0.5Bi(Ti_0.5Zn_0.5)O₃+0.05Li₂CO₃And the 1.0BaTiO synthesized in the step (3)₃-0.5BiAlO₃+0.05Li₂CO₃According to 0.70BiFeO₃-0.2BaTiO₃-0.05BiAlO₃-0.05Bi(Ti_0.5Zn_0.5)O₃+0.01Li₂CO₃+0.01MnCO₃+0.025Bi₂O₃The mixture is mixed, wherein the Bi accounts for 2.5 mol percent₂O₃In order to compensate the volatilization of Bi element in the sintering process and be used as a sintering aid to promote the sintering process, the mixed powder is ball-milled for 24 hours by taking absolute ethyl alcohol as a medium, dried in an oven at 100 ℃/12 hours, sieved by a 200-mesh sieve, put into a high-alumina crucible to be compacted and covered, and then put into a closed tube furnace to be put into a sealed tube furnace to be heated to 780 ℃ by pure oxygen at the heating rate of 250 ℃/h for heat preservation for 4 hours to synthesize 0.70BiFeO₃-0.20BaTiO₃-0.05Bi(Ti_0.5Zn_0.5)O₃-0.05BiAlO₃+0.01Li₂CO₃+0.01MnCO₃+0.025Bi₂O₃Pre-burning the powder, cooling to below 200 ℃, and taking out for later use;

(5) carrying out secondary ball milling on the pre-sintered powder synthesized in the step (4) for 24 hours by taking absolute ethyl alcohol as a medium, taking out and drying the powder, and sieving the powder by a 200-mesh sieve;

(6) adding the sieved powder into 5% PVA solution with mass percentage concentration for granulation, and performing compression molding in a steel die under 100MPa, wherein the inner diameter of the die is 1 cm;

(7) placing the molded plain sheet into a muffle furnace, slowly heating to 600 ℃ at the heating rate of 60 ℃/h, and keeping the temperature for 24 hours to discharge glue; then rapidly heating to 970 ℃ at the heating rate of 20 ℃/min, preserving the heat for 120 minutes, and cooling to the room temperature along with the furnace;

(8) polishing the sintered sample into a sheet with two smooth surfaces and a thickness of 1mm, coating a silver electrode, and burning silver at 650 ℃/30 minutes for later use;

(9) polarizing the piezoelectric ceramic plate coated with the silver electrode in silicone oil, wherein the polarizing electric field is 6000V/mm, the polarizing temperature is 150 ℃, the polarizing time is 30 minutes, keeping the electric field and cooling to the room temperature.

The performance measurements are as follows:

example 2:

composition 0.725BiFeO₃-0.175BaTiO₃-0.075Bi(Ti_0.5Zn_0.5)O₃-0.025BiAlO₃+0.01Li₂CO₃+0.01MnCO₃+0.025Bi₂O₃The preparation method is the same as that of example 1, except that the formula ratio is changed, and the sintering temperature in step (7) is 960 ℃ for 120 minutes.

The performance measurements are as follows:

d33(pC/N)	Qm	kp(％)	εr	Tc(℃)	Td(℃)	tanδ(％)
							137	97.4	0.293	125	596	580	3.31

example 3:

the components: 0.75BiFeO₃-0.175BaTiO₃-0.05Bi(Ti_0.5Zn_0.5)O₃-0.025BiAlO₃+0.006CuO+0.01MnCO₃+0.025Bi₂O₃The preparation method is the same as that of example 1, except that the formula is changed, CuO is adopted, and the sintering temperature in the step (7) is 960 ℃ and the temperature is kept for 120 minutes.

The performance measurements are as follows:

d33(pC/N)	Qm	kp(％)	εr	Tc(℃)	Td(℃)	tanδ(％)
							126	93.6	0.285	133	575	560	4.07

example 4:

the components: 0.725BiFeO₃-0.15BaTiO₃-0.075Bi(Ti_0.5Zn_0.5)O₃-0.05BiAlO₃+0.01MnCO₃+0.01Ba(W_0.5Cu_0.5)O₃+0.025Bi₂O₃The preparation method is the same as example 1, except that the formula is changed, Ba (W) is adopted_0.5Cu_0.5)O₃And the sintering temperature in the step (7) is 960 ℃ for 120 minutes.

The performance measurements are as follows:

d33(pC/N)	Qm	kp(％)	εr	Tc(℃)	Td(℃)	tanδ(％)
							133	99.4	0.26	106	560	525	3.82

the upper and lower limits and interval values of the ingredients listed in the invention and the upper and lower limits and interval values of the process parameters can all realize the invention, and the implementation is not always carried out here.

Claims (1)

1. A bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic is characterized in that: has the general formula ofxBiFeO₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃ -tBiAlO₃+mP+nMnCO₃+2.5%Bi₂O₃Whereinx、y、z、t、m、nRepresents a mole fraction, P is Ba (W)_0.5Cu_0.5)O₃、CuO、Li₂CO₃One or the combination of two sintering aids, and is more than or equal to 0.6x≤0.8，0.15≤y≤0.3，0.05≤z≤0.15，0<t≤0.10，0<m≤0.1，0<n≤0.1；

The preparation method of the bismuth ferrite-barium titanate-zinc bismuth titanate-bismuth aluminate high-temperature lead-free piezoelectric ceramic comprises the following steps: using BaTiO₃The perovskite structure is used as a phase structure inducer, sintering aids are added, and a stepwise synthesis method is adopted to respectively synthesize BaTiO₃-aBi(Ti_0.5Zn_0.5)O₃+cP and BaTiO₃-bBiAlO₃+dP, then mixing it with Bi₂O₃、Fe₂O₃Mixed calcination synthesisxBiFeO₃-yBaTiO₃-zBi(Ti_0.5Zn_0.5)O₃ -tBiAlO₃+mP+nMnCO₃+ 2.5%Bi₂O₃Pre-sintering the powder in a sintering furnace,

the preparation method comprises the following steps:

(1) to analytically pure TiO₂、BaCO₃As a raw material, according to BaTiO₃The mixed powder is ball-milled for 24 hours by taking absolute ethyl alcohol as a medium, dried and sieved in an oven at 100 ℃/12 hours, put into a high-aluminum crucible for compaction and capping, then put into a muffle furnace for heat preservation at 980 ℃ for 6 hours for synthesis, cooled to below 200 ℃ and taken out for standby;

(2) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、TiO₂、ZnO、Li₂CO₃、W₂O₃CuO as raw material, according to BaTiO₃-aBi(Ti_0.5Zn_0.5)O₃+cP is mixed according to the proportion, wherein P is sintering aid Ba (W)_0.5Cu_0.5)O₃、Li₂CO₃One or a combination of two kinds of sintering aids of CuO, and 0<a≤0.60，0<cNot more than 0.1, adding anhydrous ethanol as medium to the mixed powderBall-milling for 24 hours, taking out the materials at 100 ℃/12 hours, drying and sieving the materials in an oven, putting the materials into a high-alumina crucible, compacting and covering the materials, putting the materials into a muffle furnace, keeping the temperature of the materials at 900-950 ℃ for 4 hours, synthesizing the materials, cooling the materials to below 200 ℃, and taking the materials out for later use;

(3) the BaTiO synthesized in the step (1) is₃And analytically pure Bi₂O₃、Al₂O₃、Li₂CO₃、W₂O₃CuO as raw material, according to BaTiO₃-bBiAlO₃+dP is mixed according to the proportion, wherein P is sintering aid Ba (W)_0.5Cu_0.5)O₃、Li₂CO₃One or a combination of two kinds of sintering aids of CuO, and 0<b≤0.60，0<dBall milling the mixed powder for 24 hours by taking absolute ethyl alcohol as a medium, taking out the mixed powder at the temperature of 100 ℃/12 hours, drying and sieving the mixed powder in an oven, putting the dried powder into a high-alumina crucible, compacting and covering the crucible, putting the crucible into a muffle furnace, keeping the temperature of 800-850 ℃ for 4 hours, synthesizing the mixture, cooling the mixture to below 200 ℃, and taking the mixture out for later use;

(4) adding Bi₂O₃、Fe₂O₃With the BaTiO synthesized in the step (2)₃-aBi(Ti_0.5Zn_0.5)O₃+cP and BaTiO synthesized in step (3)₃-bBiAlO₃+dP is according toxBiFeO₃-yBaTiO₃-z Bi(Ti_0.5Zn_0.5)O₃-tBiAlO₃+ mP+nMnCO₃+0.025Bi₂O₃The ingredients are mixed, and the mixing ratio is more than or equal to 0.6x≤0.8，0.15≤y≤0.3，0.05≤z≤0.15，0<t≤0.10，0<m≤0.1，0<nBall milling the mixed powder with absolute ethyl alcohol as medium for 24 hr, drying at 100 deg.c/12 hr in oven, sieving, compacting in high alumina crucible and covering, introducing pure oxygen in sealed tubular furnace at 250 deg.c/h to 780 deg.c/4 h to synthesizexBiFeO₃-yBaTiO₃-zBiAlO₃+ tBi(Ti_0.5Zn_0.5)O₃+mP+nMnCO₃Keeping the temperature for 4 hours and coolingCooling to below 200 deg.C, and taking out;

(5) carrying out secondary ball milling on the calcined powder synthesized in the step (4) for 24 hours by taking absolute ethyl alcohol as a medium, taking out, drying and sieving;

(6) adding the sieved powder into 5% PVA solution with mass percentage concentration for granulation, and performing compression molding in a steel die under 100MPa, wherein the inner diameter of the die is 1 cm;

(7) placing the molded plain sheet into a muffle furnace, slowly heating to 600 ℃ at the heating rate of 60 ℃/h, and keeping the temperature for 24 hours to discharge glue; then rapidly heating to 960-1000 ℃ at the heating rate of 20 ℃/min, preserving the heat for 120 minutes, and cooling to room temperature along with the furnace;

(8) polishing the sintered sample into a sheet with two smooth surfaces and a thickness of 1mm, coating a silver electrode, and burning silver at 650 ℃/30 minutes for later use;

(9) polarizing the piezoelectric ceramic plate coated with the silver electrode in silicone oil, wherein the polarizing electric field is 6000V/mm, the polarizing temperature is 150 ℃, the polarizing time is 30 minutes, and keeping the electric field to cool to the room temperature.