A bismuth ferrite-based high-temperature piezoelectric ceramic material and a preparation method thereof

Abstract

The application provides a bismuth ferrite-based high-temperature piezoelectric ceramic material and a preparation method, belongs to the piezoelectric ceramic material field, and is applied to a high-temperature vibration sensor. 1.01 FeO3-(1-x)[0.13PbTiO3-0.24BaTiO3]-xBiGaO3-1% mol MnO2, 0 < x ≤ 0.05. By adding PbTiO3-BaTiO3-BiGaO3, a quaternary high-temperature piezoelectric ceramic system is formed, high T C High-temperature piezoelectric ceramic material with high piezoelectricity, and the content is controlled, the volatilization of Bi is inhibited, and the process window is expanded.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric ceramic materials, specifically relating to a bismuth ferrite-based high-temperature piezoelectric ceramic material and its preparation method. Background Technology

[0002] Piezoelectric materials are a class of novel functional materials capable of converting mechanical energy into electrical energy, and are widely used in many fields such as communications, home appliances, and computers. As a core component of sensors, the piezoelectric properties of piezoelectric materials directly affect key parameters such as the device's operating environment, transmission power, and signal sensitivity. With technological advancements, the application range of piezoelectric materials has further expanded, and the demand for piezoelectric materials capable of operating in extreme environments has been rising in recent years. Currently, there is an urgent need in some specialized fields for next-generation piezoelectric devices based on high-temperature piezoelectric materials, but high-performance, high-temperature-operating piezoelectric ceramics are currently very scarce. While piezoelectric functional materials on the market, mainly zirconate titanate-based ceramics, exhibit excellent overall electrical properties, their Curie temperature Ti is limited. C The temperature is relatively low (250-380℃), and due to the thermal depolarization of the material, its safe operating temperature is only at its Curie temperature T. C Less than half of the materials have a high piezoelectric coefficient, making them unsuitable for manufacturing high-temperature piezoelectric devices. Currently, vibration sensors operating above 260°C are all based on non-perovskite materials with low piezoelectric coefficients, or even use piezoelectric single-crystal materials with complex manufacturing processes and high costs. Therefore, there is an urgent need in the industry for high-voltage piezoelectric ceramic materials that can be stably applied to temperatures of 300°C and above. Developing high-temperature piezoelectric materials with excellent performance, low cost, and good thermal stability is both urgent and of significant practical importance.

[0003] On the other hand, a bottleneck exists in piezoelectric materials where piezoelectric properties are mutually constrained by the Curie temperature. Based on thermodynamic theory, the piezoelectric coefficient is proportional to the product of spontaneous polarization intensity and relative permittivity. Typically, the relative permittivity and spontaneous polarization intensity of ferroelectric materials are mutually constrained; therefore, improving piezoelectric performance requires a trade-off between these two physical quantities. The higher the Curie temperature of a ferroelectric material, the greater its polarization intensity at room temperature; however, at the same time, the polarization vector is less susceptible to external field disturbances, leading to a decrease in the relative permittivity. Therefore, simply lowering the Curie temperature cannot continuously increase the piezoelectric effect of ferroelectric materials. These problems hinder the development and practical application of high-temperature piezoelectric ceramics. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a bismuth ferrite-based high-temperature piezoelectric ceramic material and its preparation method. By adding PbTiO3-BaTiO3-BiGaO3 to construct a quaternary high-temperature piezoelectric ceramic system, a high-TT ceramic material suitable for engineering applications is obtained. C High-temperature piezoelectric ceramic materials with high voltage and high voltage properties were developed, and the content of the above-mentioned materials was controlled to suppress the volatilization of Bi and expand the process window.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a bismuth ferrite-based high-temperature piezoelectric ceramic material for use in high-temperature vibration sensors, with the following chemical composition:

[0007] 0.63Bi 1.01 FeO3-(1-x)[0.13PbTiO3-0.24BaTiO3]-xBiGaO3-1%molMnO2, 0 <x≤0.05。

[0008] Furthermore, 0.03 ≤ x ≤ 0.05.

[0009] This invention provides a method for preparing the above-mentioned bismuth ferrite-based high-temperature piezoelectric ceramic material, characterized by the following steps: S1. Weighing raw materials of metal carbonate or oxide according to stoichiometric ratio, mixing and calcining once to obtain a pre-synthesized powder; S2. Ball milling the pre-synthesized powder, mixing and granulating, sieving and pressing into sheets, and sintering to obtain a ceramic sample; S3. Polishing the ceramic sample, cleaning and drying it, and then performing three modified annealing treatments. After the modified annealing treatments are completed, polarization is performed to obtain the high-temperature piezoelectric ceramic material.

[0010] Furthermore, in step S1, the mixing process involves ball milling the metal carbonate or oxide with alcohol or water as the medium for 8-12 hours at a speed of 300-500 r / min, followed by drying after ball milling.

[0011] Furthermore, the process parameters for the first calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment at a synthesis temperature of 750-850℃ for 3-5 hours.

[0012] Furthermore, in step S2, the process parameters for ball milling are as follows: the pre-synthesized powder is ball-milled for 8-12 hours using alcohol or water as the medium at a speed of 300-500 r / min, and then dried after ball milling.

[0013] Furthermore, the dried powder is mixed with a binder and granulated, then passed through a 100-150 mesh sieve and cold-pressed under a pressure of 200-300 MPa to obtain a ceramic green body.

[0014] Furthermore, the ceramic ligand is sintered in an oxidizing environment under normal pressure using a powder embedding method, with the temperature increased to 500-600℃ at a heating rate of 2-4℃ / min and held for at least 25min, then increased to 1000-1100℃ at a heating rate of 4-6℃ / min, and sintered for 2-3h. After sintering, it is cooled in the furnace.

[0015] Furthermore, the improved annealing treatment includes polarization treatment and annealing treatment; the annealing treatment process is as follows: after removing the silver electrode from the polarized high-temperature piezoelectric ceramic, after cleaning and drying, the temperature is raised to 300-400℃ at a heating rate of 4-6℃ / min and annealed for 1-2 hours, followed by furnace cooling.

[0016] Furthermore, the polarization process parameters are as follows: silver electrodes are coated on both ends of the ceramic sample, polarization is carried out in silicone oil at 80-100℃, the polarization electric field is 5-6KV / mm, and the polarization time is 30-40min.

[0017] The beneficial effects of the technical solutions provided by the embodiments of the present invention include:

[0018] 1. The ceramic composition of the present invention has both high piezoelectricity and high Curie temperature, and can be obtained using traditional piezoelectric ceramic preparation techniques and industrial raw materials, resulting in low cost and practicality.

[0019] 2. Compared to doped solid solution-constructed quasi-isomorphic phase-boundary binary and ternary ceramic compositions, this invention introduces a BiFeO3-based quaternary composition designed from perovskite materials with different phase structures and lattice distortions, which also possesses high T C Taking advantage of the piezoelectric properties of high voltage, and employing a special polarization-annealing process, the piezoelectric performance is further significantly improved, allowing for the controllability of high d-values. 33 High T C With low tanσ, a high-performance high-temperature piezoelectric ceramic material is finally obtained, which meets the application requirements of high-temperature vibration sensors. The process has good repeatability, no other impurities, and good performance stability.

[0020] 3. This method provides a new approach for preparing high-performance high-temperature piezoelectric ceramics, with extremely high performance tunability, and can be applied to various piezoelectric ceramic systems.

[0021] 4. By using a combination of 0.13PbTiO3-0.24BaTiO3 and MnO2 within a defined content range, the volatilization of Bi in BiFeO3 can be controlled, resulting in a maximum Bi volatilization of 1%mol. After volatilization to about 1%mol, the Bi is passivated. This allows for precise control of the Bi content and, on the other hand, the passivation process can expand the process window and reduce the difficulty of process implementation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 XRD pattern of the high-temperature piezoelectric ceramic 0.63Bi 1.01 FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1% mol MnO2 prepared in Example 1 of the present invention;

[0024] Figure 2 SEM surface morphology diagram of the high-temperature piezoelectric ceramic 0.63Bi 1.01 FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1% mol MnO2 prepared in Example 1 of the present invention;

[0025] Figure 3 Dielectric temperature spectrum of the high-temperature piezoelectric ceramic 0.63Bi 1.01 FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1% mol MnO2 prepared in the embodiments of the present invention. The solid line is the relative dielectric constant, and the dashed line is the dielectric loss. Detailed implementation manners

[0026] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] An embodiment of the present invention discloses a bismuth ferrite-based high-temperature piezoelectric ceramic material with a chemical composition of 0.63Bi 1.01 FeO3-(1-x)[0.13PbTiO3-0.24BaTiO3]-xBiGaO3-1% mol MnO2, which is applied to a high-temperature vibration sensor, where 0 < x ≤ 0.05. Preferably, 0.03 ≤ x ≤ 0.05.

[0028] The present invention utilizes the fact that bismuth ferrite BiFeO3 has a large polarization intensity (~90 - 100 μC / cm 2 ) and a very high Curie temperature T C (~823 °C) at room temperature, and there is a very large octahedral oxygen torsion distortion, making depolarization of the ferroelectric phase very difficult, which has a natural advantage in the design of high-temperature piezoelectric materials. However, it is difficult to prepare pure-phase BiFeO3, and there are problems such as small high-temperature conductivity and large losses, which are not conducive to its application as a high-temperature piezoelectric material. On the one hand, the present invention constructs a morphotropic phase boundary by introducing tetragonal BaTiO3 and orthorhombic BiGaO3 into rhombohedral BiFeO3, uses the phase boundary to enhance piezoelectricity, and at the same time introducing BaTiO3 and BiGaO3 can reduce the dielectric loss of the system and increase the resistivity of the sample; at the same time, introducing tetragonal PbTiO3 with a large lattice distortion into the system to maintain its large lattice distortion and keep its high polarization rate and high TC Based on the above approach, a quaternary high-temperature piezoelectric ceramic system of BiFeO3-PbTiO3-BaTiO3-BiGaO3 was designed to obtain high TT C High voltage electrical properties (T) C ~464℃,d 33 High-temperature piezoelectric ceramic materials (~395 pC / N); secondly, by using a combination of 0.13PbTiO3-0.24BaTiO3 and MnO2 within a limited content range, the volatilization of Bi in BiFeO3 can be controlled, so that the maximum volatilization of Bi is 1%mol, and passivation is performed after volatilization to about 1%mol. On the one hand, precise control of Bi content can be achieved, and on the other hand, passivation can expand the process window and reduce the difficulty of process implementation.

[0029] This invention also proposes a method for preparing the above-mentioned bismuth ferrite-based high-temperature piezoelectric ceramic material, characterized by comprising the following steps:

[0030] S1. Weigh the raw materials of metal carbonate or oxide according to the stoichiometric ratio, mix them and calcine them once to obtain the pre-synthesized powder.

[0031] First, the raw materials of analytically pure or chemically pure carbonates or oxides are prepared and then mixed. The mixing is carried out by ball milling. The mixing process is as follows: the metal carbonates or oxides are ball milled with alcohol or water as the medium for 8-12 hours at a speed of 300-500 r / min. After ball milling, they are dried. The process parameters for the first calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment at a synthesis temperature of 750-850℃ for 3-5 hours to obtain the pre-synthesized powder.

[0032] The alcohol is preferably anhydrous ethanol.

[0033] To improve the oxidation degree of the raw materials, the preferred oxidation environment of the present invention is an oxygen flow rate of 40-50 mL / min.

[0034] S2. The pre-synthesized powder is ball-milled, mixed and granulated, sieved, pressed into tablets, and sintered to obtain a ceramic sample.

[0035] The ball milling process parameters are as follows: the pre-synthesized powder is ball-milled for 8-12 hours with alcohol or water as the medium at a speed of 300-500 r / min, and then dried; the dried powder is mixed with a binder and granulated, with the binder being 0.8 wt% PVB of the powder mass, and then cold-pressed under a pressure of 200-300 MPa after passing through a 100-150 mesh sieve to obtain a ceramic green body, which is a round disc with a diameter of 8-10 mm and a thickness of 1-1.5 mm; the ceramic ligand is sintered in an oxidizing environment at normal pressure using a powder embedding method, heated to 500-600℃ at a heating rate of 2-4℃ / min and held for at least 25 min, then heated to 1000-1100℃ at a heating rate of 4-6℃ / min and sintered for 2-3 hours, and then cooled in the furnace after sintering to obtain the ceramic sample.

[0036] S3. Polish the ceramic sample, clean and dry it, and then perform three improved annealing treatments. After the improved annealing treatments are completed, polarize the sample to obtain the high-temperature piezoelectric ceramic material.

[0037] The improved annealing treatment includes polarization treatment and annealing treatment; the annealing treatment process is as follows: after polarization treatment, the silver electrode of the high-temperature piezoelectric ceramic is removed, preferably by immersing the high-temperature piezoelectric ceramic in acetone, cleaning and drying, and then annealing at a heating rate of 4-6℃ / min to 300-400℃ for 1-2 hours, followed by furnace cooling. Three sinterings can greatly improve the polarization intensity, but should not exceed three times, as exceeding three times will cause the piezoelectric ceramic to break down and become unusable.

[0038] The polarization process parameters are as follows: silver electrodes are coated on both ends of the ceramic sample, polarization is carried out in silicone oil at 80-100℃, the polarization electric field is 5-6KV / mm, and the polarization time is 30-40min.

[0039] Specifically, the cleaning process of this invention employs ultrasonic cleaning.

[0040] It should be noted that in this invention, "ceramic blank" refers to the state of powder after cold pressing without sintering; "ceramic sample" refers to the state of sintering but without polarization treatment; and "high-temperature piezoelectric ceramic" refers to the state of having silver electrodes at both ends after without polarization treatment.

[0041] To better illustrate the embodiments of the present invention, the present invention will be further described in detail below through specific examples.

[0042] Example 1

[0043] The embodiments of the present invention provide

[0044] 0.63Bi 1.01A method for preparing high-temperature piezoelectric ceramics of FeO3-(1-x)[0.13PbTiO3-0.24BaTiO3]-xBiGaO3-1%mol MnO2, wherein x takes values ​​of 0.01, 0.02, 0.03, 0.04, and 0.05, includes the following steps:

[0045] S1. Weigh the raw materials of metal carbonates or oxides according to the stoichiometric ratio, mix them, and calcine them once to obtain a pre-synthesized powder. The metal carbonates or oxides are ball-milled for 10 hours at a speed of 300 r / min using alcohol or water as the medium, and then dried after ball milling. The process parameters for the first calcination are as follows: calcine the dried mixed raw materials in an oxidizing environment at a synthesis temperature of 750℃ for 3 hours to obtain the pre-synthesized powder.

[0046] S2. The pre-synthesized powder is ball-milled, mixed and granulated, sieved, pressed into tablets, and sintered to obtain a ceramic sample. The ball-milling process parameters are as follows: the pre-synthesized powder is ball-milled for 10 hours with alcohol or water as the medium at a speed of 400 r / min, and then dried; the dried powder is mixed with a binder and granulated, sieved through a 100-150 mesh sieve, and then cold-pressed under a pressure of 200 MPa to obtain a ceramic green body; the ceramic ligand is sintered in an oxidizing environment at normal pressure using a powder embedding method, heated to 550℃ at a heating rate of 3℃ / min and held for 1 hour, then heated to 1050℃ at a heating rate of 5℃ / min and sintered for 3 hours, and then cooled in the furnace after sintering to obtain the ceramic sample.

[0047] S3. After polishing, cleaning, and drying the ceramic sample, perform three modified annealing treatments. After the modified annealing treatment, polarize the sample to obtain the high-temperature piezoelectric ceramic material. The modified annealing treatment includes polarization treatment and annealing treatment. The annealing process is as follows: remove the silver electrode from the polarized high-temperature piezoelectric ceramic, preferably by immersing the high-temperature piezoelectric ceramic in acetone, cleaning and drying it, then heating it to 350°C at a heating rate of 5°C / min for annealing for 1.5 hours, followed by furnace cooling.

[0048] The polarization process parameters are as follows: silver electrodes are coated on both ends of the ceramic sample, polarization is carried out in silicone oil at 90°C, the polarization electric field is 5-6KV / mm, and the polarization time is 30-40min.

[0049] like Figure 1 As shown, there is a transformation from a trigonal phase structure to a tetragonal phase structure. When 0.03≤x≤0.05, the trigonal and tetragonal phase structures coexist, and the ratio of trigonal to tetragonal phases is in the range of 1:0.8-1.2, resulting in better piezoelectric performance.

[0050] like Figure 2As shown, when x takes values within the range of 0 < x ≤ 0.05, the morphological differences are not significant. Taking the morphological map of x = 0.03 as a representative, it can be seen that its microstructure is dense.

[0051] For 0.63Bi 1.01 The properties of the high-temperature piezoelectric ceramic 0.63BiFeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2 were tested. Its piezoelectric coefficient d 33 is 395 pC / N, and the Curie temperature T C is 464 °C. As Figure 3 shown, the relative dielectric constant ε r is 1120, and the dielectric loss tanσ is 0.016, and it can remain stable above 300 °C.

[0052] Example 2

[0053] The embodiment of the present invention provides

[0054] 0.63Bi 1.01 A preparation method of the high-temperature piezoelectric ceramic 0.63BiFeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2, comprising the following steps:

[0055] S1. Weigh the raw materials of metal carbonate or oxide according to the stoichiometric ratio, mix the materials and conduct a primary calcination to obtain a pre-synthesized powder. The metal carbonate or oxide uses alcohol or water as a medium, ball-mills for 8 h at a rotation speed of 300 r / min, and after the ball-milling is completed, it is dried; the process parameters of the primary calcination are: calcine the dried mixed raw materials in an oxidation environment, the synthesis temperature is 750 °C, and keep the temperature for 3 h to obtain the pre-synthesized powder.

[0056] S2. Ball-mill the pre-synthesized powder, mix and granulate it, screen it, press it into tablets, and conduct sintering to obtain a ceramic sample. The process parameters of the ball-milling are: the pre-synthesized powder uses alcohol or water as a medium, ball-mills for 8 h at a rotation speed of 300 r / min, and after the ball-milling, it is dried; the dried powder is mixed and granulated with a binder, screened through a 100 - 150 mesh sieve, and cold-pressed into a ceramic blank under a pressure of 200 MPa; the ceramic blank is sintered in an oxidation environment by the powder-embedding method under normal pressure, heated to 500 °C at a heating rate of 2 °C / min and kept the temperature for 25 min, heated to 1000 °C at a heating rate of 4 °C / min, sintered for 2 h, and cooled with the furnace after the sintering is completed to obtain the ceramic sample.

[0057] S3. After polishing, cleaning, and drying the ceramic sample, perform three modified annealing treatments. After the modified annealing treatment, polarize the sample to obtain the high-temperature piezoelectric ceramic material. The modified annealing treatment includes polarization treatment and annealing treatment. The annealing process is as follows: remove the silver electrode from the polarized high-temperature piezoelectric ceramic, preferably by immersing the high-temperature piezoelectric ceramic in acetone, cleaning and drying it, then heating it to 300℃ at a heating rate of 4℃ / min for annealing for 1 hour, followed by furnace cooling.

[0058] The polarization process parameters are as follows: silver electrodes are coated on both ends of the ceramic sample, polarization is carried out in silicone oil at 80°C, the polarization electric field is 5-6KV / mm, and the polarization time is 30-40min.

[0059] It is mainly composed of trigonal to tetragonal phase structures, and its microstructure is dense.

[0060] Its performance was tested, and its piezoelectric coefficient d 33 It is 330 pC / N, Curie temperature T C The temperature is 464℃, and the relative permittivity ε r The dielectric constant is 1150, the dielectric loss tanσ is 0.017, and it can remain stable above 300℃.

[0061] Example 3

[0062] The embodiments of the present invention provide

[0063] 0.63Bi 1.01 The preparation method of high-temperature piezoelectric ceramics of FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2 includes the following steps:

[0064] S1. Weigh the raw materials of metal carbonates or oxides according to the stoichiometric ratio, mix them, and calcine them once to obtain a pre-synthesized powder. The metal carbonates or oxides are ball-milled for 12 hours at a speed of 500 r / min using alcohol or water as the medium, and then dried after ball milling. The process parameters for the first calcination are as follows: calcine the dried mixed raw materials in an oxidizing environment at a synthesis temperature of 850℃ for 5 hours to obtain the pre-synthesized powder.

[0065] S2. The pre-synthesized powder is ball-milled, mixed and granulated, sieved, pressed into tablets, and sintered to obtain a ceramic sample. The ball-milling process parameters are as follows: the pre-synthesized powder is ball-milled for 12 hours with alcohol or water as the medium at a speed of 500 r / min, and then dried; the dried powder is mixed with a binder and granulated, passed through a 100-150 mesh sieve, and then cold-pressed under a pressure of 300 MPa to obtain a ceramic green body; the ceramic ligand is sintered in an oxidizing environment at normal pressure using a powder embedding method, heated to 600℃ at a heating rate of 4℃ / min and held for 30 min, then heated to 1100℃ at a heating rate of 6℃ / min and sintered for 3 hours, and then cooled in the furnace after sintering to obtain the ceramic sample.

[0066] S3. After polishing, cleaning, and drying the ceramic sample, perform two modified annealing treatments. After the modified annealing treatment, polarize the sample to obtain the high-temperature piezoelectric ceramic material. The modified annealing treatment includes polarization treatment and annealing treatment. The annealing process is as follows: remove the silver electrode from the polarized high-temperature piezoelectric ceramic, preferably by immersing the high-temperature piezoelectric ceramic in acetone, cleaning and drying it, then heating it to 400℃ at a heating rate of 6℃ / min for annealing for 2 hours, followed by furnace cooling.

[0067] The polarization process parameters are as follows: silver electrodes are coated on both ends of the ceramic sample, polarization is carried out in silicone oil at 100°C, the polarization electric field is 5-6KV / mm, and the polarization time is 30-40min.

[0068] It is mainly composed of trigonal to tetragonal phase structures, and its microstructure is dense.

[0069] Its performance was tested, and its piezoelectric coefficient d 33 It is 340 pC / N, Curie temperature T C The temperature is 464℃, and the relative permittivity ε r The dielectric constant is 1100, the dielectric loss tanσ is 0.016, and it can remain stable above 300℃.

[0070] Comparative Example 1

[0071] Unlike Example 1, this comparative example focuses on the following chemical composition:

[0072] 0.63Bi 1.01 A high-temperature piezoelectric ceramic of FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2, in S3 of this embodiment, the ceramic sample is polished, cleaned and dried, and then subjected to a modified annealing treatment.

[0073] The prepared high-temperature piezoelectric ceramics are mainly trigonal-tetragonal phase structures with dense microstructures.

[0074] Its performance was tested, and its piezoelectric coefficient d 33 It is 224 pC / N, Curie temperature T C The temperature is 464℃, and the relative permittivity ε r The dielectric constant is 1120, the dielectric loss tanσ is 0.016, and it can remain stable above 300℃.

[0075] Comparative Example 2

[0076] Unlike Example 1, this comparative example focuses on the following chemical composition:

[0077] 0.63Bi 1.01 In S3 of this embodiment, the high-temperature piezoelectric ceramic of FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2 is polished, cleaned and dried, and then subjected to two modified annealing treatments.

[0078] The prepared high-temperature piezoelectric ceramics are mainly trigonal-tetragonal phase structures with dense microstructures.

[0079] Its performance was tested, and its piezoelectric coefficient d 33 It is 329 pC / N, Curie temperature T C The temperature is 464℃, and the relative permittivity ε r The dielectric constant is 1130, the dielectric loss tanσ is 0.018, and it can remain stable above 300℃.

[0080] Comparative Example 3

[0081] Unlike Example 1, this comparative example focuses on the following chemical composition:

[0082] 0.63Bi 1.01 High-temperature piezoelectric ceramic of FeO3-(0.97)[0.15PbTiO3-0.22BaTiO3]-0.03BiGaO3-1%mol MnO2.

[0083] The prepared high-temperature piezoelectric ceramics are mainly trigonal-tetragonal phase structures with dense microstructures.

[0084] Its performance was tested, and its piezoelectric coefficient d 33 It is 210 pC / N, Curie temperature T C The temperature is 484℃, and the relative permittivity ε r The dielectric constant is 1030, the dielectric loss tanσ is 0.019, and it can remain stable above 300℃.

[0085] Comparative Example 4

[0086] Unlike Example 1, this comparative example focuses on the following chemical composition:

[0087] 0.63Bi 1.01 High-temperature piezoelectric ceramic of FeO3-(0.97)[0.12PbTiO3-0.25BaTiO3]-0.03BiGaO3-1%mol MnO2.

[0088] The prepared high-temperature piezoelectric ceramics are mainly trigonal in structure and have a dense microstructure.

[0089] Its performance was tested, and its piezoelectric coefficient d 33 It is 220 pC / N, Curie temperature T C The temperature is 455℃, and the relative permittivity ε r The dielectric constant is 1160, the dielectric loss tanσ is 0.018, and it can remain stable above 300℃.

[0090] Comparative Example 5

[0091] Unlike Example 1, this comparative example focuses on the following chemical composition:

[0092] 0.63Bi 1.01 High-temperature piezoelectric ceramic of FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-0.8%mol MnO2.

[0093] The prepared high-temperature piezoelectric ceramics are mainly trigonal in structure and have a dense microstructure.

[0094] Its performance was tested, and its piezoelectric coefficient d 33 It is 195 pC / N, Curie temperature T C The temperature is 451℃, and the relative permittivity ε r The dielectric constant is 1170, the dielectric loss tanσ is 0.018, and it can remain stable above 300℃.

[0095] The 0.63Bi prepared by comparing Example 1, Comparative Examples 1 and 2 1.01 Given FeO3-(0.97)[0.13PbTiO3-0.24BaTiO3]-0.03BiGaO3-1%mol MnO2, it can be seen that, firstly, the piezoelectricity is improved by the phase boundary energy. Simultaneously, the appropriate introduction of MnO2, BaTiO3, and BiGaO3 can reduce the dielectric loss of the system. Furthermore, the introduction of tetragonal PbTiO3 with large lattice distortion maintains its high polarizability and high TT. C It also has the characteristics of large lattice distortion and high T CIt possesses the advantages of high voltage electrical properties at the quasi-isomorphic phase boundary; secondly, based on this structure, a special polarization-annealing process is adopted to simultaneously obtain high d 33 (~379pC / N), High T C With a temperature range of ~464℃ and a low tanσ (~0.016), this material exhibits excellent comprehensive performance, making it a high-performance high-temperature piezoelectric ceramic material. Through Examples 1 and Comparative Examples 3-5, it is evident that using a combination of 0.13PbTiO3-0.24BaTiO3 with MnO2 within a defined content range allows for control of Bi volatilization in BiFeO3, achieving a maximum Bi volatilization of 1%mol. Passivation occurs after approximately 1%mol volatilization, enabling precise control of the Bi content. Furthermore, passivation expands the process window, reducing the difficulty of process implementation and resulting in a piezoelectric ceramic material with high d... 33 High T C And low tanσ.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bismuth ferrite-based high temperature piezoelectric ceramic material for use in high temperature vibration sensors, characterized in that, Chemical composition 0.63Bi 1.01 FeO3-(1-x)[0.13PbTiO3-0.24BaTiO3]-xBiGaO3-1% mol MnO2, 0.01≤x≤0.05; The preparation method of the bismuth ferrite-based high-temperature piezoelectric ceramic material comprises the following steps: S1. Raw materials of metal carbonates or oxides are weighed according to stoichiometric ratios, mixed and subjected to primary calcination to obtain pre-synthesized powders; S2. The pre-synthesized powders are subjected to ball milling, mixed and granulated, sieved, and then pressed into tablets, and sintered to obtain ceramic samples; S3. The ceramic samples are polished, cleaned and dried, and then subjected to three times of improved annealing treatment, and after the improved annealing treatment, polarization is performed, thereby obtaining the high-temperature piezoelectric ceramic material; The improved annealing treatment comprises polarization treatment and annealing treatment; The annealing treatment process is as follows: after the high-temperature piezoelectric ceramic after polarization treatment is removed of silver electrodes, cleaned and dried, it is heated to 300-400 DEG C at a heating rate of 4-6 DEG C / min and annealed for 1-2 h, and then cooled in the furnace.

2. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 1, characterized in that, 0.03≤x≤0.05。 3. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 1, characterized in that, In the step S1, the mixing is as follows: the metal carbonates or oxides are ball milled in alcohol or water as a medium at a rotation speed of 300-500 r / min for 8-12 h, and then dried.

4. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 3, characterized in that, The process parameters of the primary calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment at a synthesis temperature of 750-850 DEG C for 3-5 h.

5. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 1, characterized in that, In the step S2, the process parameters of the ball milling are as follows: the pre-synthesized powders are ball milled in alcohol or water as a medium at a rotation speed of 300-500 r / min for 8-12 h, and then dried.

6. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 5, characterized in that, The dried powders are mixed with a binder to form granules, which are cold-pressed into ceramic green bodies under a pressure of 200-300 MPa after being sieved through a 100-150 mesh sieve.

7. The bismuth ferrite-based high temperature piezoelectric ceramic material according to claim 6, characterized in that, The ceramic green bodies are sintered in an oxidizing environment by the powder embedding method under normal pressure at a heating rate of 2-4 DEG C / min to 500-600 DEG C for at least 25 min, and then heated to 1000-1100 DEG C at a heating rate of 4-6 DEG C / min, and sintered for 2-3 h, and then cooled in the furnace after sintering.

8. The bismuth ferrite-based high temperature piezoelectric ceramic material of claim 1, wherein, The process parameters of the polarization are as follows: silver electrodes are coated on both ends of the ceramic samples, and then polarization is performed in silicon oil at 80-100 DEG C, the polarization electric field is 5-6 KV / mm, and the polarization time is 30-40 min.

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