High-power high-temperature piezoelectric ceramic for scene and preparation method thereof

Abstract

The application discloses high-temperature piezoelectric ceramics for high-power scenes and a preparation method thereof, and belongs to the technical field of piezoelectric ceramics. The high-temperature piezoelectric ceramic is Mn-doped lead zirconate titanate-based piezoelectric ceramic; the lead zirconate titanate-based piezoelectric ceramic is a three-phase solid solution of Pb(Yb 1 / 2 Nb 1 / 2 )O3, PbZrO3 and PbTiO3; and the doping mode of the Mn element is metal oxide MnO2 doping or composite oxide Pb(Mn 1 / 3 Nb 2 / 3 )O3 doping. The application solves the process problems existing in material industrialization by controlling the composition of the material, overcomes the problem that high piezoelectric performance and high Curie temperature and high mechanical quality factor are difficult to be compatible, and obtains high-power high-temperature piezoelectric ceramics with excellent comprehensive performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of piezoelectric ceramics, and particularly relates to a high-power scene high-temperature piezoelectric ceramic and a preparation method thereof. BACKGROUND

[0002] Piezoelectric ceramics are a kind of functional materials for realizing mechanical energy and electrical energy coupling and conversion (transduction). They have very wide applications in advanced manufacturing, electronic information, energy detection and national defense, such as piezoelectric drivers, ultrasonic motors, deep well sound detection, transducers and vibration sensors, and piezoelectric ceramic materials are the sensitive elements and core components of the entire system. In practical applications, some parameters reflecting the performance of the materials are usually selected to evaluate the advantages and disadvantages of the materials. Common piezoelectric ceramic performance parameters mainly include piezoelectric constant, dielectric constant, mechanical quality factor Qm, dielectric loss tanδ, etc. High piezoelectric performance generally means that the main function of the system or device is more excellent; and low loss means that the performance stability of the device or system in long-term work.

[0003] According to performance characteristics, piezoelectric ceramics can be generally divided into two categories of "soft" and "hard". "Soft" piezoelectric ceramics have high piezoelectric performance, dielectric performance and electromechanical performance, and are mainly applied to sensors, medical imaging, filters, etc. "Hard" piezoelectric ceramics have high mechanical quality factor and low dielectric loss, and are the core functional materials of large power transducers, piezoelectric transformers, etc., and are widely used in sonar systems, ultrasonic detection, vibration control and other electromechanical conversion systems. In these applications, power piezoelectric modules need to generate large elastic strain under large electrical power to exert their piezoelectric effect, and then to convert electromechanical energy. Continuous large amplitude vibration leads to large internal friction and dielectric loss and generates a large amount of heat, which is easy to cause stress damage, fatigue damage and performance deterioration, which requires large power piezoelectric materials to have high mechanical quality factor Q m and low dielectric loss tanδ on the basis of ensuring good "soft" performance, and have excellent stable performance in alternating electric field and high temperature and high pressure environment.

[0004] Due to the harsh application environment of power type ceramics, large power piezoelectric ceramics require "soft and hard" performance such as high piezoelectric constant, high mechanical quality factor Q m , low loss, high Curie temperature, etc. Due to the influence of the ferroelectric domain of piezoelectric ceramics, these performances are generally in a mutually restrictive relationship, for example, high "soft" performance often corresponds to low "hard" performance and low Curie temperature. The comprehensive requirements of these performance indicators make the preparation of large power piezoelectric materials more difficult. SUMMARY

[0005] In order to overcome the above-mentioned defects of the prior art, the present application aims to provide a high-power high-temperature piezoelectric ceramic for a scene and a preparation method thereof, which solves the process problems existing in the material industrialization by controlling the composition of the material, overcomes the problem that high piezoelectric performance and high mechanical quality factor are difficult to be compatible, and obtains a high-power high-temperature piezoelectric ceramic with excellent comprehensive performance.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The present application provides a high-power high-temperature piezoelectric ceramic for a scene, wherein the high-temperature piezoelectric ceramic is a Mn element doped lead zirconate titanate-based piezoelectric ceramic; the lead zirconate titanate-based piezoelectric ceramic is a three-phase solid solution of Pb(Yb 1 / 2 Nb 1 / 2 )O3, PbZrO3 and PbTiO3.

[0008] The doping mode of the Mn element is metal oxide MnO2 doping or composite oxide Pb(Mn 1 / 3 Nb 2 / 3 )O3 doping.

[0009] In one embodiment, when the doping mode of the Mn element is metal oxide MnO2 doping, the molecular formula of the Mn element doped lead zirconate titanate-based piezoelectric ceramic is (1-x-y)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zMnO2, wherein x is in the range of 0.1-0.6, y is in the range of 0.1-0.6, and z is in the range of 0.01-0.1.

[0010] In one embodiment, when the doping mode of the Mn element is composite oxide Pb(Mn 1 / 3 Nb 2 / 3 )O3 doping, the molecular formula of the Mn element doped lead zirconate titanate-based piezoelectric ceramic is (1-x-y-z)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 )O3, wherein x is in the range of 0.1-0.6, y is in the range of 0.1-0.6, and z is in the range of 0.01-0.2.

[0011] The present application also provides a preparation method of the high-power high-temperature piezoelectric ceramic for a scene, comprising the following steps:

[0012] S1: Prepare MnNb2O6 precursor powder or MnO2 and YbNbO4 precursor powder. The raw materials are prepared according to the molecular formula of Mn element doped lead zirconate titanate-based piezoelectric ceramics, and then ball-milled, dried and sieved in sequence to obtain a raw material mixture.

[0013] S2: The raw material mixture is pre-calcined and then cooled to room temperature, followed by grinding to obtain pre-calcined powder;

[0014] S3: The pre-fired powder is ball-milled, then dried, ground and sieved to obtain ceramic powder;

[0015] S4: The ceramic powder is pressed into a blank, and then the blank is subjected to pressureless closed sintering treatment to obtain the fired piezoelectric ceramic.

[0016] S5: Polish, silver-plated and polarized the fired piezoelectric ceramic in sequence to obtain high-temperature piezoelectric ceramic for high-power applications.

[0017] In one embodiment, when the Mn element originates from MnNb2O6 precursor powder, the Mn element doping mode in the lead zirconate titanate-based piezoelectric ceramic is the composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3 doping;

[0018] When the Mn element originates from MnO2, the Mn element in the lead zirconate titanate-based piezoelectric ceramic is doped by the metal oxide MnO2 doping.

[0019] In one embodiment, the preparation process of the MnNb2O6 precursor powder in step S1 is as follows:

[0020] MnO2 and Nb2O5 were mixed evenly according to the stoichiometric ratio of MnNb2O6, and then ball-milled, dried, ground, and sieved in sequence. Finally, they were calcined at a temperature of 1000℃~1200℃ to obtain MnNb2O6 precursor powder.

[0021] In one embodiment, the preparation process of the YbNbO4 precursor powder in step S1 is as follows:

[0022] Yb2O3 and Nb2O5 were mixed evenly according to the stoichiometric ratio of YbNbO4, and then ball-milled, dried, ground, and sieved in sequence. Finally, they were calcined at a temperature of 1000℃~1100℃ to synthesize YbNbO4 precursor powder.

[0023] In one embodiment, the pre-firing process in S2 is as follows:

[0024] Preheat the temperature to 750℃~850℃ at a heating rate of 2~10℃ / min for 2~5 hours.

[0025] In one embodiment, the pressureless sealed sintering process in S4 is as follows:

[0026] The blank is embedded in homogeneous ceramic powder, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1100-1300℃ at a heating rate of 2-5℃ / min, sintered for 3-5 hours, and then naturally cooled to room temperature with the furnace.

[0027] In one implementation, the polishing process in step S5 is as follows:

[0028] The upper and lower surfaces of the fired piezoelectric ceramics were polished with 600-2000 grit sandpaper, then polished with metallographic sandpaper to a thickness of 0.8-1.2 mm, followed by ultrasonic cleaning with deionized water and ethanol, and then dried.

[0029] The silver plating process is as follows:

[0030] The silver paste was evenly coated on the upper and lower surfaces of the polished and fired piezoelectric ceramic, and then placed in a resistance furnace. The temperature was maintained at 500℃~850℃ for 5min~60min, and then the furnace was allowed to cool naturally to room temperature.

[0031] The polarization process is as follows:

[0032] The silver-plated and fired piezoelectric ceramic is placed in silicone oil and polarized along the thickness direction using a DC or AC electric field; the polarization temperature is 90℃~150℃, the polarization voltage is 10kV / cm~50kV / cm, and the polarization voltage holding time is 10~60min.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention provides a high-temperature piezoelectric ceramic for high-power applications, which is a Mn-doped lead zirconate titanate-based piezoelectric ceramic; wherein the Mn doping method is either MnO2 metal oxide doping or Pb(Mn) composite oxide doping. 1 / 3Nb 2 / 3 O3 doping is designed to hard-dopat PYN-PZT high-temperature piezoelectric ceramics, increasing the mechanical quality factor and reducing losses. Specifically, due to Mn... 2+ / 3+ Replaced Ti 4+ / Zr 4+Excess negative charge appears in the crystal lattice. To maintain charge neutrality, oxygen vacancies are generated. These oxygen vacancies cause cell contraction, resulting in a "pinning effect," which makes domain walls difficult to move. This reduces losses caused by domain wall movement and increases the mechanical quality factor. Meanwhile, the introduction of Mn reduces piezoelectric properties. However, due to the high Curie temperature and high piezoelectric properties of the PYN-PZT system, Mn-doped lead zirconate titanate-based piezoelectric ceramics can maintain high Curie temperature and piezoelectric properties while improving the mechanical quality factor.

[0035] Furthermore, the metal oxide MnO2 and the composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3-doped PYN-PZT-based piezoelectric ceramics exhibit high power performance and Curie temperatures, both exceeding 350℃. 33 The coercive field E of MnO2-doped PYN-PZT-based piezoelectric ceramics is above 250 pC / N. C Up to 25kV / cm, internal bias field E i Up to 5kV / cm, Q m The temperature can reach 1800°C, the vibration velocity can reach 0.8 m / s, and the loss change rate under strong alternating electric field is about 80%. Composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 The coercive field E of O3-doped PYN-PZT-based piezoelectric ceramics C Up to 26kV / cm, internal bias field E i Up to 8.5kV / cm, Q m The vibration velocity can reach 1 m / s, and the loss change rate under a strong alternating electric field is only 30%. This indicates that Mn-doped PYN-PZT high-temperature piezoelectric ceramics are suitable for high-power applications under strong fields or strong drives. Furthermore, the above further demonstrates that the hard composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3 doping exhibits superior high-power performance compared to metal oxide MnO2 doping. Therefore, this research provides some assistance for the design of high-power piezoelectric ceramics.

[0036] This invention also provides a method for preparing high-temperature piezoelectric ceramics for high-power applications. This method involves obtaining ceramic powder and then subjecting the powder to pressureless closed-circuit sintering to obtain the fired piezoelectric ceramic. Pressureless closed-circuit sintering means that no external pressure is applied to the blank during the sintering process, which helps reduce ceramic structural deformation or cracking caused by pressure. The closed-circuit design ensures the stability and consistency of the sintering environment, reducing interference from external factors (such as oxygen and moisture) on the sintering process. Conventional sintering processes may involve applying external pressure or using an open sintering environment, which may lead to inhomogeneity in the ceramic structure or contamination from external factors. Pressureless closed-circuit sintering, by avoiding these potential problems, allows for more precise control of the sintering process, resulting in piezoelectric ceramics with a pure perovskite crystal structure, dense microstructure, and uniform grain size, which is beneficial for improving the overall performance of high-power piezoelectric ceramics. Attached Figure Description

[0037] Figure 1 A cross-sectional morphology image of the PMnN-doped PYN-PZT piezoelectric ceramic prepared in Example 8 of the present invention, obtained by scanning electron microscopy (SEM).

[0038] Figure 2 The graph shows the temperature variation trend of the dielectric constant of MnO2 and PMnN-doped PYN-PZT prepared in Examples 1, 2, 4 and 5 of the present invention.

[0039] Figure 3 Hysteresis loop diagrams of the PYN-PZT piezoelectric ceramics prepared in Examples 3 and 6 of the present invention;

[0040] Figure 4 Impedance diagram and phase angle diagram of PMnN-doped PYN-PZT ceramic prepared in Example 6;

[0041] Figure 5 This is a schematic diagram of the vibration velocity of the PMnN-doped PYN-PZT ceramic prepared in Example 5.

[0042] Figure 6 Schematic diagram of the loss of MnO2 and PMnN-doped PYN-PZT ceramics prepared in Examples 2 and 5 under a strong AC electric field;

[0043] Figure 7 XRD patterns of PYN-PZT, MnO2-doped PYN-PZT, and PMnN-doped PYN-PZT piezoelectric ceramics. Detailed Implementation

[0044] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0045] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0046] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0047] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0048] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0049] This invention provides a high-temperature piezoelectric ceramic for high-power applications and its preparation method. By controlling the material composition and ceramic sintering process, this invention obtains a high-temperature piezoelectric ceramic for high-power applications with excellent comprehensive performance, solves the process problems existing in the industrialization of materials, and overcomes the problem that it is difficult to simultaneously achieve high voltage performance, high Curie temperature, and high mechanical quality factor.

[0050] In piezoelectric material research, a common method to improve high-power performance is through hard doping (such as Cr). 3+ Fe 2 / 3+ (etc.), while the present invention, through the composition design of piezoelectric ceramics, in Pb(Yb 1 / 2 Nb 1 / 2 Based on the O3-PbZrO3-PbTiO3 system, through doping with the metal oxide MnO2 and the composite oxide Pb(Mn) 1 / 3 Nb 2 / 3Two doping methods were used to introduce Mn into Pb(PMnN)O3 doping. Both methods yielded high-power piezoelectric ceramics with excellent overall performance, exhibiting high Curie temperature, high softness, and high hardness, making them promising candidates for power devices. Furthermore, the research results of this project indicate that the composite oxide Pb(PMnN)... 1 / 3 Nb 2 / 3 Piezoelectric ceramics doped with PMnN exhibit superior high-power performance compared to those doped with MnO2. Therefore, this research provides some assistance for the design of high-power piezoelectric ceramics.

[0051] This invention provides a high-temperature piezoelectric ceramic for high-power applications. The high-temperature piezoelectric ceramic is a Mn-doped lead zirconate titanate-based piezoelectric ceramic (Pb(Yb)). 1 / 2 Nb 1 / 2 (O3-PbZrO3-PbTiO3 ceramic), wherein the lead zirconate titanate group is Pb(Yb) 1 / 2Nb 1 / 2 A three-phase solid solution of O3, PbZrO3, and PbTiO3, with Mn doped in the form of metal oxide MnO2 or composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3 doping results in a perovskite structure for the piezoelectric ceramic.

[0052] When Mn is doped with the metal oxide MnO2, the molecular formula of the Mn-doped lead zirconate titanate-based piezoelectric ceramic is (1-xy)Pb(Yb). 1 / 2 Nb 1 / 2 O3-yPbZrO3-xPbTiO3+zMnO2 (x ranges from 0.1 to 0.6, y ranges from 0.1 to 0.6, and z ranges from 0.01 to 0.1).

[0053] The doping mode of Mn is the composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 When doped with O3, the molecular formula of Mn-doped lead zirconate titanate-based piezoelectric ceramics is (1-xyz)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 O3 (x ranges from 0.1 to 0.6, y ranges from 0.1 to 0.6, and z ranges from 0.01 to 0.2).

[0054] The Q of the above MnO2-doped PYN-PZT piezoelectric ceramics m The temperature can reach 1800, and the vibration velocity can reach 0.8 m / s. Pb(Mn) 1 / 3Nb 2 / 3 Q of O3-doped PYN-PZT piezoelectric ceramics m It can reach 3000, and the vibration velocity can reach 1m / s, making it suitable for high-power transducer applications.

[0055] This invention also provides a method for preparing high-temperature piezoelectric ceramics for high-power applications, comprising the following steps:

[0056] S1: Prepare MnNb2O6 precursor powder or MnO2 and YbNbO4 precursor powder, and formulate the raw materials according to the molecular formula of Mn-doped lead zirconate titanate-based piezoelectric ceramics. Then, sequentially ball mill, dry, and sieve to obtain a raw material mixture. Specifically, when the Mn element originates from the MnNb2O6 precursor powder, the Mn element doping mode in the Mn-doped lead zirconate titanate-based piezoelectric ceramic is a composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3 doping; when the Mn element originates from MnO2, the Mn element doping mode in the lead zirconate titanate-based piezoelectric ceramic is metal oxide MnO2 doping.

[0057] S2: The raw material mixture is pre-calcined and then cooled to room temperature, followed by grinding to obtain pre-calcined powder;

[0058] S3: The pre-fired powder is ball-milled, then dried, ground and sieved to obtain ceramic powder;

[0059] S4: The ceramic powder is pressed into a blank, and then the blank is subjected to pressureless closed sintering treatment to obtain the fired piezoelectric ceramic.

[0060] S5: Polish, silver-plated and polarized the fired piezoelectric ceramic in sequence to obtain high-temperature piezoelectric ceramic for high-power applications.

[0061] In a specific embodiment, the preparation process of MnNb2O6 precursor powder in S1 is as follows: MnO2 and Nb2O5 are mixed evenly according to the stoichiometric ratio of MnNb2O6, and then ball-milled, dried, ground, and sieved in sequence. Finally, the mixture is calcined at a temperature of 1000℃~1200℃ to obtain MnNb2O6 precursor powder.

[0062] In a specific embodiment, the preparation process of YbNbO4 precursor powder in S1 is as follows: Yb2O3 and Nb2O5 are mixed evenly according to the stoichiometric ratio of YbNbO4, and then ball-milled, dried, ground, and sieved in sequence, and finally calcined at a temperature of 1000℃~1100℃ to synthesize YbNbO4 precursor powder.

[0063] In a specific implementation, the pre-firing process in S2 is as follows: the temperature is increased to 750℃ to 850℃ at a heating rate of 2 to 10℃ / min for 2 to 5 hours.

[0064] In a specific embodiment, the pressureless closed-loop sintering process in S4 is as follows: the blank is embedded in homogeneous ceramic powder, placed on a zirconia plate, and then the zirconia plate is placed in an alumina closed crucible. The temperature is increased to 1100–1300°C at a heating rate of 2–5°C / min, and sintered for 3–5 hours. Afterward, it is naturally cooled to room temperature with the furnace. Pressureless closed-loop sintering improves the stability and controllability of the sintering process, helps to obtain a more uniform ceramic structure, reduces interference from external factors on the sintering process, lowers the risk of ceramic contamination, and helps to improve the quality and performance of the sintered piezoelectric ceramics, especially for high-temperature applications in high-power scenarios.

[0065] In a specific implementation, the polishing process in S5 is as follows: the upper and lower surfaces of the fired piezoelectric ceramic are polished with 600-2000 grit sandpaper, then polished with metallographic sandpaper to a thickness of 0.8-1.2 mm, then ultrasonically cleaned with deionized water and ethanol in sequence, and then dried.

[0066] In a specific embodiment, the silver plating process in S5 is as follows: silver paste is uniformly coated on the upper and lower surfaces of the polished and fired piezoelectric ceramic, and then placed in a resistance furnace. The temperature is maintained at 500℃~850℃ for 5min~60min, and then the furnace is allowed to cool naturally to room temperature.

[0067] In a specific implementation, the polarization process in S5 is as follows: the silver-plated and fired piezoelectric ceramic is placed in silicone oil and polarized along the thickness direction using a DC or AC electric field; the polarization temperature is 90℃~150℃, the polarization voltage is 10kV / cm~50kV / cm, and the polarization voltage holding time is 10~60min.

[0068] More specifically, a method for preparing high-temperature piezoelectric ceramics for high-power applications is provided, with the following specific steps:

[0069] Step 1: Preparation of ceramic powder:

[0070] When using lead zirconate titanate-based piezoelectric ceramics doped with the metal oxide MnO2, the molecular formula of the ceramic powder is (1-xy)Pb(Yb). 1 / 2 Nb 1 / 2 The method for preparing the aforementioned ceramic powder is as follows: O3-yPbZrO3-xPbTiO3+zMnO2

[0071] (1) Preparation of YbNbO4 precursor powder

[0072] Yb₂O₃ and Nb₂O₅ were weighed out according to the stoichiometric ratio of YbNbO₄ as raw materials. All the weighed raw materials were mixed evenly and placed into a nylon can. Using zirconia balls as grinding balls and anhydrous ethanol as the ball milling medium, the mixture was thoroughly mixed and milled for 18–72 hours at 150–300 rpm. The zirconia balls were separated, and the raw material mixture was dried at 80–100℃ for 12–24 hours. The mixture was then ground in a mortar and passed through an 80–200 mesh sieve. The sieved powder was placed in an alumina crucible, covered, and calcined at 1000–1100℃ for 5–10 hours to synthesize YbNbO₄ precursor powder.

[0073] (2) Ingredients

[0074] According to (1-xy)Pb(Yb) 1 / 2 Nb 1 / 2 The stoichiometric ratio of O3-yPbZrO3-xPbTiO3+zMnO2 is used for batching (x ranges from 0.1 to 0.6, y ranges from 0.1 to 0.6, and z ranges from 0.01 to 0.1). For example, 0.2Pb(Yb) 1 / 2 Nb 1 / 2 The following formula was prepared: O3-0.3PbZrO3-0.5PbTiO3+0.05MnO2. 67.0748g of PbO (99.9% purity), 49.9157g of YbNbO, 11.1091g of ZrO2 (99.9% purity), 12.0004g of TiO2 (99.9% purity), and 0.3955g of MnO2 (99% purity) were weighed as raw materials. All raw materials were mixed thoroughly and placed in a nylon container. Using zirconium balls as grinding media and anhydrous ethanol as the milling medium, the mixture was milled for 18–72 hours. The zirconium balls were separated, and the raw material mixture was dried at 80–100℃ for 12–24 hours. The mixture was then ground in a mortar and pestle and passed through an 80–200 mesh sieve to obtain the final raw material mixture.

[0075] (3) Preheating

[0076] Place the sieved raw material mixture from step (2) into an alumina crucible, compact it with an agate rod, cover it, place it in a resistance furnace, pre-fire it at 750℃ to 850℃ for 2 to 5 hours at a heating rate of 2 to 10℃ / min, cool it naturally to room temperature, remove it from the furnace, grind it with a mortar and pestle to obtain pre-fired powder.

[0077] (4) Secondary ball milling

[0078] The pre-calcined powder is placed in a nylon can, and milled for 18–72 hours at 150–300 rpm using zirconium balls as grinding media and anhydrous ethanol as the milling medium. The zirconium balls are then separated, and the pre-calcined powder is dried at 80–100°C for 12–48 hours. The powder is then ground in a mortar and pestle and passed through an 80–200 mesh sieve to obtain (1-xy)Pb(Yb).1 / 2 Nb 1 / 2 O3-yPbZrO3-xPbTiO3+zMnO2 ceramic powder.

[0079] When using composite oxides Pb(Mn) 1 / 3 Nb 2 / 3 When O3 is doped with lead zirconate titanate-based piezoelectric ceramics, the molecular formula of the ceramic powder is (1-xyz)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 The method for preparing the aforementioned ceramic powder is as follows:

[0080] (1) Preparation of YbNbO4 and MnNb2O6 precursor powders

[0081] YbNbO4 precursor powder: Yb2O3 and Nb2O5 were weighed out according to the stoichiometric ratio of YbNbO4 as raw materials. All weighed raw materials were mixed evenly and placed in a nylon can. Using zirconia balls as grinding balls and anhydrous ethanol as the ball milling medium, the mixture was ball milled at 150-300 rpm for 18-24 hours. The zirconia balls were separated, and the raw material mixture was dried at 80℃-100℃ for 12-48 hours. The mixture was then ground in a mortar and passed through an 80-200 mesh sieve. The sieved powder was placed in an alumina crucible, covered, and calcined at 1000℃-1100℃ for 5-10 hours to synthesize YbNbO4 precursor powder.

[0082] MnNb2O6 precursor powder: MnO2 and Nb2O5 were weighed separately as raw materials according to the stoichiometric ratio of MnNb2O6. All weighed raw materials were mixed evenly and placed in a nylon can. Using zirconia balls as grinding balls and anhydrous ethanol as the ball milling medium, the mixture was thoroughly mixed and milled for 18-72 hours at 150-300 rpm. The zirconia balls were separated, and the raw material mixture was dried at 80℃-100℃ for 12-48 hours. The mixture was then ground in a mortar and passed through an 80-200 mesh sieve. The sieved powder was placed in an alumina crucible, covered, and calcined at 1000℃-1200℃ for 5-10 hours to synthesize MnNb2O6 precursor powder.

[0083] (2) Ingredients

[0084] According to (1-xyz)Pb(Yb) 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3The ingredients are prepared according to the stoichiometric ratio of O3 (x ranges from 0.1 to 0.6, y ranges from 0.1 to 0.6, and z ranges from 0.01 to 0.2). For example, 0.05Pb (Yb) 1 / 2 Nb 1 / 2 )O3-0.3PbZrO3-0.5PbTiO3+0.15Pb(Mn 1 / 3 Nb 2 / 3 To obtain the raw materials, weigh out 68.7063g of PbO (99.9% purity), 2.5392g of YbNbO4, 11.3793g of ZrO2 (99.9% purity), 12.2923g of TiO2 (99.9% purity), and 5.1830g of MnNb2O6. Mix all the weighed raw materials evenly and put them into a nylon can. Use zirconium balls as grinding balls and anhydrous ethanol as the ball milling medium. Mix and mill for 18-72 hours. Separate the zirconium balls, dry the raw material mixture at 80-100℃ for 12-48 hours, grind it with a mortar and pestle, and pass it through an 80-200 mesh sieve to obtain the raw material mixture.

[0085] (3) Preheating

[0086] Place the sieved raw material mixture from step (2) into an alumina crucible, compact it with an agate rod, cover it, place it in a resistance furnace, pre-calcine it at a heating rate of 2-10℃ / min to 700℃-950℃ for 2-8 hours, cool it naturally to room temperature, remove it from the furnace, grind it with a mortar and pestle to obtain pre-calcined powder.

[0087] (4) Secondary ball milling

[0088] The pre-calcined powder is placed in a nylon can, and milled for 18–72 hours using zirconium balls as grinding media and anhydrous ethanol as the milling medium at 150–300 rpm. The zirconium balls are then separated, and the pre-calcined powder is dried at 80–100°C for 12–48 hours. The powder is then ground in a mortar and pestle and passed through an 80–200 mesh sieve to obtain (1-xyz)Pb(Yb). 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 O3 ceramic powder.

[0089] Step 2: Fabrication of PYN-PZT-based high-temperature piezoelectric ceramics for high-power applications:

[0090] (1) Tableting

[0091] The two ceramic powders that have passed through an 80-200 mesh sieve are pressed into cylindrical blanks using a powder tablet press, and then subjected to cold isostatic pressing at a pressure of 200-300 MPa for 15-20 minutes.

[0092] (2) Pressureless closed sintering

[0093] Two cylindrical blanks with different compositions are embedded in their respective homogeneous powders, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1100-1300℃ at a heating rate of 2-5℃ / min, sintered for 3-5 hours, and then naturally cooled to room temperature in the furnace to obtain the fired piezoelectric ceramic.

[0094] (3) Polishing

[0095] The upper and lower surfaces of the two piezoelectric ceramics sintered in step (2) were polished with 600-2000 grit sandpaper, and then polished with metallographic sandpaper to a thickness of 0.8-1.2 mm. After that, they were ultrasonically cleaned with deionized water and ethanol respectively, and then dried.

[0096] (4) Silver-plated electrodes

[0097] The silver paste is evenly coated on the two polished surfaces of the ceramic, placed in a resistance furnace, and kept at a temperature of 500℃~850℃ for 5min~60min. The ceramic is then allowed to cool naturally to room temperature to obtain a piezoelectric ceramic with silver electrode plating.

[0098] (5) Polarization

[0099] The two piezoelectric ceramics after silver plating in step (4) were placed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 90℃~150℃, the polarization voltage was 10kV / cm~50kV / cm, and the polarization voltage was maintained for 10~60 minutes, resulting in the following chemical formulas: (1-xy)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zMnO2 and (1-xyz)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 O3 piezoelectric ceramics.

[0100] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0101] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0102] Example

[0103] The general formula for high-temperature piezoelectric ceramics for high-power applications provided in this invention embodiment is:

[0104] When the Mn element originates from the metal oxide MnO2, the metal oxide MnO2 is doped with Pb(Yb) 1 / 2 Nb 1 / 2 O3-PbZrO3-PbTiO3:

[0105] The molecular formula of Example 1 is 0.2Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.2PbZrO3-0.6PbTiO3+0.01MnO2;

[0106] The molecular formula of Example 2 is 0.1Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2;

[0107] The molecular formula of Example 3 is 0.45Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.05MnO2;

[0108] The molecular formula of Example 4 is 0.4Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.1MnO2;

[0109] When the Mn element originates from the MnNb2O6 precursor powder, the composite oxide Pb(Mn) 1 / 3 Nb 2 / 3 O3-doped Pb(Yb) 1 / 2 Nb 1 / 2 O3-PbZrO3-PbTiO3:

[0110] The molecular formula of Example 5 is 0.19Pb(Yb). 1 / 2 Nb 1 / 2)O3-0.2PbZrO3-0.6PbTiO3+0.01Pb(Mn 1 / 3Nb 2 / 3 O3;

[0111] The molecular formula of Example 6 is 0.01Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.09Pb(Mn 1 / 3Nb 2 / 3 O3;

[0112] The molecular formula of Example 7 is 0.3Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.15Pb(Mn 1 / 3Nb 2 / 3 O3;

[0113] The molecular formula of Example 8 is 0.2Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.2Pb(Mn 1 / 3 Nb 2 / 3 )O3.

[0114] Example 1

[0115] Preparation of metal oxide MnO2-doped PYN-PZT ceramics:

[0116] (1) Preparation of YbNbO4 precursor powder

[0117] According to the stoichiometric ratio of YbNbO4, 59.7804 g of Yb2O3 with a purity of 99.9% and 40.3197 g of Nb2O5 with a purity of 99.9% were weighed as raw materials. All the weighed raw materials were mixed evenly and placed in a nylon can. Zirconia balls were used as grinding balls and anhydrous ethanol was used as the ball milling medium. The mass ratio of anhydrous ethanol to the raw material mixture was 1:1.2. The mixture was ball milled at 250 rpm for 48 hours. The zirconia balls were separated, and the raw material mixture was placed in a drying oven and dried at 80℃ for 24 hours. It was then ground in a mortar and pestle for 30 minutes and passed through a 200-mesh sieve. The sieved powder was placed in an alumina crucible, covered, and calcined at 1000℃ for 10 hours to synthesize YbNbO4 precursor powder.

[0118] (2) Ingredients

[0119] For 0.2Pb(Yb) 1 / 2 Nb 1 / 2The sample was prepared as follows: O3-0.2PbZrO3-0.6PbTiO3+0.01MnO2, according to 0.2Pb(Yb 1 / 2 Nb 1 / 2 The stoichiometry of O3-0.2PbZrO3-0.6PbTiO3+0.01MnO2 was determined by weighing 67.9594g of PbO (99.9% purity), 10.0465g of YbNbO4, 7.5037g of ZrO2 (99.9% purity), 14.5905g of TiO2 (99.9% purity), and 0.2671g of MnO2 (99% purity) as raw materials. The raw material mixture was placed in a nylon container and milled with zirconium balls as grinding balls and anhydrous ethanol as the milling medium. The mass ratio of anhydrous ethanol to the raw material mixture was 1:1.2. The mixture was milled at 250 rpm for 48 hours. The zirconium balls were separated, and the raw material mixture was dried in a drying oven at 80℃ for 14 hours. It was then ground in a mortar and pestle for 30 minutes and passed through an 80-mesh sieve.

[0120] (3) Preheating

[0121] The raw material mixture after passing through an 80-mesh sieve in step (2) is placed in an alumina crucible and compacted with an agate rod to a compaction density of 1.5 g / cm³. 3 Cover the container and place it in a resistance furnace. Heat it to 850°C at a rate of 3°C / minute for 5 hours. Let it cool naturally to room temperature. Remove it from the furnace and grind it in a mortar for 30 minutes to obtain pre-calcined powder.

[0122] (4) Secondary ball milling

[0123] The pre-calcined powder was placed in a nylon can, and milled using zirconium balls as grinding media and anhydrous ethanol as the milling medium (anhydrous ethanol to pre-calcined powder mass ratio of 1:1.2) at 250 rpm for 72 hours. The zirconium balls were then separated, and the pre-calcined powder was dried in a drying oven at 80°C for 15 hours. Afterward, it was ground in a mortar for 10 minutes and passed through a 200-mesh sieve to obtain 0.2Pb(Yb). 1 / 2 Nb 1 / 2 O3-0.2PbZrO3-0.6PbTiO3+0.01MnO2 powder.

[0124] (5) Tableting

[0125] The ceramic powder that has passed through a 200-mesh sieve is pressed into cylindrical blanks using a powder press, and then subjected to cold isostatic pressing at a pressure of 300 MPa for 20 minutes.

[0126] (6) Pressureless closed sintering

[0127] Cylindrical blanks are embedded in their respective homogeneous powders, placed on zirconia plates, and then placed in a sealed alumina crucible. The temperature is increased to 1300°C at a rate of 5°C / min, and sintered for 5 hours. The blanks are then allowed to cool naturally to room temperature in the furnace to obtain the fired piezoelectric ceramics.

[0128] (7) Polishing

[0129] The upper and lower surfaces of the piezoelectric ceramic sintered in step (6) were polished with 2000-grit sandpaper, and then polished with metallographic sandpaper to a thickness of 1.2 mm. After that, they were ultrasonically cleaned with deionized water and ethanol respectively, and then dried.

[0130] (8) Silver-plated electrode

[0131] The silver paste is evenly coated on the two polished surfaces of the ceramic, placed in a resistance furnace, and kept at 850℃ for 60 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain a piezoelectric ceramic with silver electrode plating.

[0132] (9) Polarization

[0133] The piezoelectric ceramic after silver plating in step (8) was placed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 150℃, the polarization voltage was 50kV / cm, and the polarization voltage was maintained for 60 minutes, resulting in a product with the chemical formula 0.2Pb(Yb). 1 / 2 Nb 1 / 2 Piezoelectric ceramics of O3-0.2PbZrO3-0.6PbTiO3+0.01MnO2.

[0134] Example 2

[0135] Preparation of ceramic powder: For 0.1Pb(Yb) 1 / 2 Nb 1 / 2 The sample was prepared as follows: O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2, according to 0.1Pb(Yb 1 / 2 Nb 1 / 2 The stoichiometry of O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2 was determined by weighing 66.1816g of 99.9% PbO, 4.8918g of YbNbO4, 21.9223g of 99.9% ZrO2, 7.1044g of 99.9% TiO2, and 0.7804g of 99% MnO2 as raw materials and mixing them evenly to prepare 0.1Pb(Yb)O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2. 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2 piezoelectric ceramic powder.

[0136] Tableting: The ceramic powder that has passed through an 80-mesh sieve is pressed into cylindrical blanks using a powder tablet press, and then subjected to cold isostatic pressing at a pressure of 200MPa for 15 minutes.

[0137] Pressureless closed sintering: A cylindrical blank is embedded in homogeneous powder, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1100°C at a heating rate of 2°C / min, and sintered for 3 hours. The blank is then naturally cooled to room temperature in the furnace to obtain the fired piezoelectric ceramic.

[0138] Polishing: The upper and lower surfaces of the sintered piezoelectric ceramic are polished with 600-grit sandpaper, then polished with metallographic sandpaper to a thickness of 0.8mm. Afterwards, they are ultrasonically cleaned with deionized water and ethanol, and then dried.

[0139] Silver-plated electrodes: Silver paste is evenly coated on the two surfaces of the polished ceramic, placed in a resistance furnace, and kept at 500℃ for 5 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain piezoelectric ceramics with silver-plated electrodes.

[0140] Polarization: The silver-plated piezoelectric ceramic was immersed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 90℃, the polarization voltage was 10kV / cm, and the polarization voltage was maintained for 10 minutes, yielding a product with the chemical formula 0.1Pb(Yb). 1 / 2 Nb 1 / 2 Piezoelectric ceramics of O3-0.6PbZrO3-0.3PbTiO3+0.03MnO2.

[0141] The other steps and process parameters are the same as in Example 1.

[0142] Example 3

[0143] Preparation of ceramic powder: For 0.45Pb(Yb) 1 / 2 Nb 1 / 2 The sample was prepared as follows: O3-0.45PbZrO3-0.1PbTiO3+0.05MnO2, according to 0.45Pb(Yb 1 / 2 Nb 1 / 2 The stoichiometry of the reaction O3-0.45PbZrO3-0.1PbTiO3+0.05MnO2 was determined by weighing 61.9111g of PbO with a purity of 99.9%, 20.592g of YbNbO4, and ZrO2 with a purity of 99.9%.

[0144] 15.3808g of TiO2 (99.9% purity), 2.2153g of MnO2 (99% purity) were mixed evenly as raw materials to prepare 0.45Pb(Yb) 1 / 2 Nb 1 / 2)O3-0.45PbZrO3-0.1PbTiO3+0.05MnO2 piezoelectric ceramic powder.

[0145] Tableting: The ceramic powder that has passed through a 150-mesh sieve is pressed into a cylindrical blank using a powder tablet press, and then subjected to cold isostatic pressing at a pressure of 300MPa for 20 minutes.

[0146] Pressureless closed sintering: A cylindrical blank is embedded in homogeneous powder, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1300℃ at a heating rate of 2℃ / min, and sintered for 5 hours. The blank is then naturally cooled to room temperature in the furnace to obtain the fired piezoelectric ceramic.

[0147] Polishing: The upper and lower surfaces of the sintered piezoelectric ceramic are polished with 2000-grit sandpaper, and then polished to a thickness of 1mm with metallographic sandpaper. After that, they are ultrasonically cleaned with deionized water and ethanol respectively, and then dried.

[0148] Silver-plated electrodes: Silver paste is evenly coated on the two surfaces of the polished ceramic, placed in a resistance furnace, and kept at 650℃ for 60 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain piezoelectric ceramics with silver-plated electrodes.

[0149] Polarization: The silver-plated piezoelectric ceramic was immersed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 150℃, the polarization voltage was 50kV / cm, and the polarization voltage was maintained for 60 minutes, yielding a product with the chemical formula 0.45Pb(Yb). 1 / 2 Nb 1 / 2 Piezoelectric ceramics consisting of O3-0.45PbZrO3-0.1PbTiO3+0.05MnO2.

[0150] The other steps and process parameters are the same as in Example 1.

[0151] Example 4

[0152] Preparation of ceramic powder: For 0.4Pb(Yb) 1 / 2 Nb 1 / 2 The sample was prepared as follows: O3-0.1PbZrO3-0.5PbTiO3+0.1MnO2, according to 0.4Pb(Yb 1 / 2 Nb 1 / 2 The stoichiometry of the reaction O3-0.1PbZrO3-0.5PbTiO3+0.1MnO2 was determined by weighing out 65.4342g of PbO with a purity of 99.9%, 19.3464g of YbNbO4, and 99.9% ZrO2.

[0153] 3.6125g of TiO2 (99.9% purity), 11.7069g of MnO2 (99% purity) were mixed evenly as raw materials to prepare 0.4Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.1MnO2 piezoelectric ceramic powder.

[0154] The other steps and process parameters are the same as in Example 1.

[0155] Example 5

[0156] Preparation of Pb(Mn) 1 / 3 Nb 2 / 3 O3-doped PYN-PZT ceramics:

[0157] (1) Preparation of YbNbO4 and MnNb2O6 precursor powders

[0158] The preparation method of YbNbO4 precursor powder is as shown in Example 1 (1) above.

[0159] MnNb2O6 precursor powder: 24.8953g of MnO2 with a purity of 99% and 75.4291g of Nb2O5 with a purity of 99.9% were weighed out according to the stoichiometric ratio of MnNb2O6 as raw materials. All the weighed raw materials were mixed evenly and placed in a nylon can. Using zirconia balls as grinding balls and anhydrous ethanol as the ball milling medium, the mixture was ball milled at 300 rpm for 24 hours. The zirconia balls were separated, and the raw material mixture was dried at 100℃ for 24 hours. The mixture was then ground in a mortar and pestle and passed through an 80-mesh sieve. The sieved powder was placed in an alumina crucible, covered, and calcined at 1200℃ for 8 hours to synthesize MnNb2O6 precursor powder.

[0160] (2) Ingredients

[0161] For 0.19Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.2PbZrO3-0.6PbTiO3+0.01Pb(Mn 1 / 3 Nb 2 / 3 The O3 sample was prepared according to 0.19Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.2PbZrO3-0.6PbTiO3+0.01Pb(Mn 1 / 3 Nb 2 / 3To determine the stoichiometry of O3, 68.0685 g of PbO (99.9% purity), 49.5595 g of YbNbO (99.9% purity), 7.5158 g of ZrO2 (99.9% purity), 14.6139 g of TiO2 (99.9% purity), and 0.3423 g of MnNb2O (99.9% purity) were weighed as raw materials. The raw material mixture was placed in a nylon container, and zirconium balls were used as grinding balls, and anhydrous ethanol was used as the grinding medium. The mass ratio of anhydrous ethanol to the raw material mixture was 1:1.2. The mixture was ball-milled at 250 rpm for 48 hours. The zirconium balls were separated, and the raw material mixture was placed in a drying oven and dried at 80°C for 24 hours. It was then ground in a mortar and pestle for 30 minutes and passed through a 200-mesh sieve.

[0162] (3) Preheating

[0163] Place the sieved raw material mixture from step (2) into an alumina crucible, compact it with an agate rod, cover it, place it in a resistance furnace, pre-calcine it at 950°C for 5 hours at a heating rate of 2°C / min, cool it naturally to room temperature, remove it from the furnace, grind it with a mortar and pestle to obtain pre-calcined powder.

[0164] (4) Secondary ball milling

[0165] The pre-calcined powder is placed in a nylon can, and milled for 72 hours at 150–300 rpm using zirconium balls as grinding media and anhydrous ethanol as the milling medium. The zirconium balls are then separated, and the pre-calcined powder is dried at 100°C for 24 hours. Finally, it is ground in a mortar and pestle and passed through a 200-mesh sieve to obtain the desired powder.

[0166] 0.19Pb(Yb 1 / 2 Nb 1 / 2 )O3-0.2PbZrO3-0.6PbTiO3+0.01Pb(Mn 1 / 3 Nb 2 / 3 )O3 powder.

[0167] (5) Tableting

[0168] The ceramic powder that has passed through a 200-mesh sieve is pressed into cylindrical blanks using a powder press, and then subjected to cold isostatic pressing at a pressure of 300 MPa for 20 minutes.

[0169] (6) Pressureless closed sintering

[0170] Cylindrical blanks are embedded in their respective homogeneous powders, placed on zirconia plates, and then placed in a sealed alumina crucible. The temperature is increased to 1300°C at a rate of 5°C / min, and sintered for 5 hours. The blanks are then allowed to cool naturally to room temperature in the furnace to obtain the fired piezoelectric ceramics.

[0171] (7) Polishing

[0172] The upper and lower surfaces of the piezoelectric ceramic sintered in step (6) were polished with 2000-grit sandpaper, and then polished with metallographic sandpaper to a thickness of 1.2 mm. After that, they were ultrasonically cleaned with deionized water and ethanol respectively, and then dried.

[0173] (8) Silver-plated electrode

[0174] The silver paste is evenly coated on the two polished surfaces of the ceramic, placed in a resistance furnace, and kept at 850℃ for 60 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain a piezoelectric ceramic with silver electrode plating.

[0175] (9) Polarization

[0176] The piezoelectric ceramic after silver plating in step (8) was placed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 150℃, the polarization voltage was 50kV / cm, and the polarization voltage was maintained for 60 minutes, resulting in a product with the chemical formula 0.19Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.2PbZrO3-0.6PbTiO3+0.01Pb(Mn 1 / 3 Nb 2 / 3 Piezoelectric ceramics of O3.

[0177] Example 6

[0178] Preparation of ceramic powder: For 0.01Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.09Pb(Mn 1 / 3Nb 2 / 3 The O3 sample was prepared according to 0.01Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.09Pb(Mn 1 / 3 Nb 2 / 3 To determine the stoichiometry of O3, 67.1252 g of 99.9% pure PbO, 0.4962 g of 99.9% pure YbNbO, 22.2349 g of 99.9% pure ZrO2, 7.2057 g of 99.9% pure TiO2, and 3.0382 g of 99.9% pure MnNb2O6 were weighed out as raw materials and mixed evenly to prepare...

[0179] 0.01Pb(Yb 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.09Pb(Mn 1 / 3 Nb 2 / 3 O3 piezoelectric ceramic powder.

[0180] Tableting: The ceramic powder that has passed through an 80-mesh sieve is pressed into cylindrical blanks using a powder tablet press, and then subjected to cold isostatic pressing at a pressure of 200MPa for 15 minutes.

[0181] Pressureless closed sintering: A cylindrical blank is embedded in homogeneous powder, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1100°C at a heating rate of 2°C / min, and sintered for 3 hours. The blank is then naturally cooled to room temperature in the furnace to obtain the fired piezoelectric ceramic.

[0182] Polishing: The upper and lower surfaces of the sintered piezoelectric ceramic are polished with 600-grit sandpaper, then polished with metallographic sandpaper to a thickness of 0.8mm. Afterwards, they are ultrasonically cleaned with deionized water and ethanol, and then dried.

[0183] Silver-plated electrodes: Silver paste is evenly coated on the two surfaces of the polished ceramic, placed in a resistance furnace, and kept at 500℃ for 5 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain piezoelectric ceramics with silver-plated electrodes.

[0184] Polarization: The silver-plated piezoelectric ceramic was immersed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 90℃, the polarization voltage was 10kV / cm, and the polarization voltage was maintained for 10 minutes, yielding a product with the chemical formula 0.01Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.6PbZrO3-0.3PbTiO3+0.09Pb(Mn 1 / 3 Nb 2 / 3 Piezoelectric ceramics of O3.

[0185] The other steps and process parameters are the same as in Example 5.

[0186] Example 7

[0187] Preparation of ceramic powder: For 0.3Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.15Pb(Mn 1 / 3Nb 2 / 3 The O3 sample was prepared according to 0.3Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.15Pb(Mn 1 / 3 Nb 2 / 3To determine the stoichiometry of O3, 63.2984 g of 99.9% pure PbO, 14.0362 g of 99.9% pure YbNbO4, 15.7255 g of 99.9% pure ZrO2, 2.2650 g of 99.9% pure TiO2, and 64.7750 g of 99.9% pure MnNb2O were weighed out as raw materials and mixed evenly to prepare...

[0188] 0.3Pb(Yb 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.15Pb(Mn 1 / 3 Nb 2 / 3 O3 piezoelectric ceramic powder.

[0189] Tableting: The ceramic powder that has passed through a 150-mesh sieve is pressed into a cylindrical blank using a powder tablet press, and then subjected to cold isostatic pressing at a pressure of 300MPa for 20 minutes.

[0190] Pressureless closed sintering: A cylindrical blank is embedded in homogeneous powder, placed on a zirconia plate, and then placed in an alumina sealed sagger. The temperature is raised to 1300℃ at a heating rate of 2℃ / min, and sintered for 5 hours. The blank is then naturally cooled to room temperature in the furnace to obtain the fired piezoelectric ceramic.

[0191] Polishing: The upper and lower surfaces of the sintered piezoelectric ceramic are polished with 2000-grit sandpaper, and then polished to a thickness of 1mm with metallographic sandpaper. After that, they are ultrasonically cleaned with deionized water and ethanol respectively, and then dried.

[0192] Silver-plated electrodes: Silver paste is evenly coated on the two surfaces of the polished ceramic, placed in a resistance furnace, and kept at 650℃ for 60 minutes. The ceramic is then allowed to cool naturally to room temperature to obtain piezoelectric ceramics with silver-plated electrodes.

[0193] Polarization: The silver-plated piezoelectric ceramic was immersed in silicone oil and polarized along the thickness direction using a DC or AC electric field. The polarization temperature was 150℃, the polarization voltage was 50kV / cm, and the polarization voltage was maintained for 60 minutes, yielding a product with the chemical formula 0.3Pb(Yb). 1 / 2 Nb 1 / 2 )O3-0.45PbZrO3-0.1PbTiO3+0.15Pb(Mn 1 / 3 Nb 2 / 3 Piezoelectric ceramics of O3.

[0194] The other steps and process parameters are the same as in Example 5.

[0195] Example 8

[0196] Preparation of ceramic powder: For 0.2Pb(Yb) 1 / 2 Nb1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.2Pb(Mn 1 / 3 Nb 2 / 3 The O3 sample was prepared according to 0.2Pb(Yb) 1 / 2 Nb 1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.2Pb(Mn 1 / 3 Nb 2 / 3 To determine the stoichiometry of O3, 7.5197 g of PbO6 (99.9% purity), 9.9815 g of YbNbO4 (99.9% purity), 3.7276 g of ZrO2 (99.9% purity), 12.0800 g of TiO2 (99.9% purity), and 6.7813 g of MnNb2O6 (99.9% purity) were weighed as raw materials and mixed evenly to prepare...

[0197] 0.2Pb(Yb 1 / 2 Nb 1 / 2 )O3-0.1PbZrO3-0.5PbTiO3+0.2Pb(Mn 1 / 3 Nb 2 / 3 O3 piezoelectric ceramic powder.

[0198] The other steps and process parameters are the same as in Example 5.

[0199] Figure 1 The image shows the cross-sectional morphology of the PMnN-doped PYN-PZT piezoelectric ceramic prepared in Example 8 using a scanning electron microscope (SEM). As shown in the figure, the prepared piezoelectric ceramic has uniform grain size and a dense structure.

[0200] Figure 2 The graph shows the dielectric constant of MnO2 and PMnN-doped PYN-PZT prepared in Examples 1, 2, 4, and 5 as a function of temperature. The graph shows that the prepared piezoelectric ceramics have a high Curie temperature (>370℃) and can be used in high-temperature environments.

[0201] Figure 3 The figures show the hysteresis loops of the PYN-PZT piezoelectric ceramics prepared in Examples 3 and 6. As can be seen from the figures, at an electric field of 40 kV / cm, the coercive field of the MnO2-doped PYN-PZT ceramic prepared in Example 3 is 25 kV / cm, and the internal bias field is 5 kV / cm; while the coercive field of the PMnN-doped PYN-PZT ceramic prepared in Example 6 is 27 kV / cm, and the internal bias field is 8.5 kV / cm. A large coercive field can improve the withstand voltage threshold of piezoelectric ceramics, making them suitable for high-power device applications. Furthermore, when the Mn doping content is the same, PMnN doping exhibits a larger coercive field and internal bias field than MnO2 doping.

[0202] Figure 4The impedance diagram and phase angle of the PMnN-doped PYN-PZT ceramic prepared in Example 6 are shown. Q can be obtained through calculation. m With a power output of up to 3058, it boasts excellent high-power performance.

[0203] Figure 5 The vibration velocity of the PMnN-doped PYN-PZT ceramic prepared in Example 5 is approximately 0.95 m / s under an AC electric field of 3 V / mm.

[0204] Figure 6 The values ​​are the losses of MnO2 and PMnN-doped PYN-PZT ceramics prepared in Examples 2 and 5 under a strong AC electric field. The loss of MnO2-doped PYN-PZT ceramics gradually increases with the increase of electric field, while the loss of PMnN-doped PYN-PZT ceramics remains relatively stable and is low (~0.5%), indicating that it is suitable for high-power environments driven by strong electric fields.

[0205] Figure 7 These are the XRD patterns of PYN-PZT, MnO2-doped PYN-PZT, and PMnN-doped PYN-PZT piezoelectric ceramics. Figure 7 As can be seen, both PYN-PZT and Mn-doped PYN-PZT ceramics have a pure perovskite structure, with no second phase appearing.

[0206] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high power high temperature piezoelectric ceramic for a high power scene, characterized by, The high-temperature piezoelectric ceramic is a Mn-doped lead zirconate titanate-based piezoelectric ceramic; the lead zirconate titanate-based is a three-phase solid solution of Pb(Yb 1 / 2 Nb 1 / 2 )O3, PbZrO3 and PbTiO3. The doping mode of the Mn element is a composite oxide Pb(Mn 1 / 3 Nb 2 / 3 )O3 doping; The molecular formula of the Mn element doped lead zirconate titanate-based piezoelectric ceramic is (1-x-y-z)Pb(Yb 1 / 2 Nb 1 / 2 )O3-yPbZrO3-xPbTiO3+zPb(Mn 1 / 3 Nb 2 / 3 )O3, wherein x is in the range of 0.1-0.6, y is in the range of 0.1-0.6, and z is in the range of 0.01-0.

2. The high-temperature piezoelectric ceramic has a Curie temperature higher than 350°C, d 33 higher than 250 pC / N, Q m higher than 3000.

2. The method of producing a high power high temperature piezoelectric ceramic for a scene according to claim 1, characterized by, The method comprises the following steps: S1: preparing MnNb2O6 precursor powder and YbNbO4 precursor powder, and preparing a raw material mixture according to the molecular formula of Mn-doped lead zirconate titanate-based piezoelectric ceramics, and then sequentially performing ball milling, drying and sieving to obtain the raw material mixture; S2: pre-sintering the raw material mixture and then cooling to room temperature, and then performing grinding to obtain pre-sintered powder; S3: ball milling the pre-sintered powder, and then performing drying, grinding and sieving to obtain ceramic powder; S4: tabletting the ceramic powder to obtain a blank, and then performing pressureless closed sintering treatment on the blank to obtain sintered piezoelectric ceramics; S5: sequentially performing polishing, silver plating and polarization on the sintered piezoelectric ceramics to obtain high-temperature piezoelectric ceramics for high-power scenes.

3. The method of claim 2, wherein the high power high temperature piezoelectric ceramic for a scene is prepared by adding 0.1 to 0.3 wt% of Bi2O3 and 0.1 to 0.3 wt% of CeO2 to the mixture of the first and second powders. In the S1, the preparation process of the MnNb2O6 precursor powder is as follows: MnO2 and Nb2O5 are taken according to the stoichiometric ratio of MnNb2O6, and then uniformly mixed, sequentially subjected to ball milling, drying, grinding and sieving, and then calcined at a temperature of 1000-1200°C to obtain the MnNb2O6 precursor powder.

4. The method of claim 2, wherein the high power high temperature piezoelectric ceramic for a scene is prepared by adding 0.1 to 0.3 wt% of Bi2O3 and 0.1 to 0.3 wt% of CeO2 to the mixture of the first and second powders. In the S1, the preparation process of the YbNbO4 precursor powder is as follows: Yb2O3 and Nb2O5 are taken according to the stoichiometric ratio of YbNbO4, and then uniformly mixed, sequentially subjected to ball milling, drying, grinding and sieving, and then calcined at a temperature of 1000-1100°C to synthesize the YbNbO4 precursor powder.

5. The method of claim 2, wherein the high power high temperature piezoelectric ceramic for a scene is prepared by adding 0.1 to 0.3 wt% of Bi2O3 and 0.1 to 0.3 wt% of CeO2 to the mixture of the first and second powders. In the S2, the pre-sintering process is as follows: The temperature is raised to 750-850°C at a temperature raising rate of 2-10°C / min, and then pre-sintered for 2-5h.

6. The method of claim 2, wherein the high power high temperature piezoelectric ceramic for a scene is prepared by the steps of: In the S4, the process of the pressureless closed sintering treatment is as follows: ​ The blank is buried in the same ceramic powder, and placed on a zirconia flat plate, and the zirconia flat plate is placed in an alumina closed sagger, and the temperature is raised to 1100-1300°C at a temperature raising rate of 2-5°C / min, and then sintered for 3-5h, and then naturally cooled to room temperature in the furnace.

7. The method for preparing high-temperature piezoelectric ceramics for high-power applications according to claim 2, characterized in that, In the S5, the process of the polishing is as follows: The upper surface and the lower surface of the sintered piezoelectric ceramics are polished by using 600-2000-mesh sandpaper, and then polished to a thickness of 0.8-1.2mm by using metallographic sandpaper, and then sequentially subjected to ultrasonic cleaning by using deionized water and ethanol, and then dried; The process of the silver plating is as follows: The silver paste is uniformly coated on the upper surface and the lower surface of the sintered piezoelectric ceramics after polishing, and then placed in a resistance furnace, and then naturally cooled to room temperature in the furnace under the condition that the temperature is 500-850°C and the temperature is maintained for 5-60min; The process of the polarization is as follows: The sintered piezoelectric ceramics after silver plating is placed in silicon oil, and then polarized along the thickness direction by using a direct current electric field or an alternating current electric field; the polarization temperature is 90-150°C, the polarization voltage is 10-50kV / cm, and the voltage maintaining time for polarization is 10-60min.

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