A lead zirconate titanate-based high-power piezoelectric ceramic and a preparation method thereof

Abstract

This invention discloses a novel lead zirconate titanate-based high-power piezoelectric ceramic and its preparation method, relating to the field of piezoelectric ceramics and their preparation technology for high-power applications. The lead zirconate titanate-based high-power piezoelectric ceramic of this invention is 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 O3+xFe2O3&Yb2O3mol%, this piezoelectric ceramic introduces Fe to generate oxygen vacancies. 2+ / Fe 3+ Ions and Yb that generate lead or oxygen vacancies 3+ Ions, thus forming a double vacancy of lead vacancy and oxygen vacancy that can regulate domain wall energy, have high piezoelectric coefficient, quality factor, low dielectric loss, high electromechanical coupling coefficient and excellent temperature stability, which improves the application range of this type of piezoelectric ceramic material in piezoelectric high power application scenarios.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric ceramics, specifically relating to a novel lead zirconate titanate-based high-power piezoelectric ceramic and its preparation method. Background Technology

[0002] Piezoelectric materials have abundant polar axes and no center of symmetry in their crystal structure. Therefore, under external force, the centers of positive and negative ions in the crystal can not coincide, causing a change in the total electric torque. This allows for the interconversion of mechanical and electrical energy, making them core components in numerous devices such as sensors, ultrasonic motors, and underwater transducers. They are widely used in electronic communications, medical equipment, aerospace, and other fields. Furthermore, piezoelectric ceramics are favored by the market due to their low cost, high performance tunability, strong chemical stability, simple preparation process, and ease of processing into various shapes, offering a very broad application prospect.

[0003] Piezoelectric ceramics are generally divided into two main categories: "soft" and "hard." Among them, "hard" piezoelectric ceramics have a higher Q value. m With low tanδ, it has become the mainstay of high-power devices, widely used not only in industrial and civilian fields but also irreplaceable in military and "high-precision" technology fields, such as ultrasonic motors, transducers and piezoelectric gyroscopes in the aerospace field, large sonar systems in the marine field, ultrasonic scalpels in the biomedical field, and piezoelectric filters in the communications field.

[0004] With the miniaturization, intelligentization, and wide-temperature-range application of high-power devices, the performance requirements for "hard" piezoelectric ceramics are gradually increasing. In high-power resonant applications, vibration velocity is a key parameter for measuring power, and power is determined by the piezoelectric coefficient d. 33 and mechanical quality factor Q m The product determines d. Therefore, increasing d 33 and Q m A high Q value is beneficial for improving the efficiency of high-power devices. However, in hard piezoelectric materials, the "hard" property (high Q) is beneficial for improving the efficiency of high-power devices. m And small tanδ) and "soft" performance (high d) 33 Electromechanical coupling coefficient k p and dielectric constant ε r There is a mutually restrictive relationship between them. This is mainly because the addition of oxygen vacancies inhibits the transformation of ferroelectric domains and domain wall movement, thereby increasing Q. m This lowered tanδ, but it suppressed d 33Furthermore, it is well known that "hard" high-power piezoelectric materials with excellent stability are beneficial for meeting practical application requirements. Therefore, "hard" high-power piezoelectric ceramics face two problems that need to be solved: first, how to simultaneously obtain a large piezoelectric coefficient and a large mechanical quality factor; and second, how to simultaneously obtain a high piezoelectric coefficient and excellent temperature stability.

[0005] Fe was introduced through acceptor doping. 2+ / Fe 3+ The ion is a reinforcement of Q in Pb(Zr,Ti)O3-based hard piezoelectric materials. m And a widely used and effective method for reducing tanδ, in which Fe 2+ / Fe 3+ The radius of the 6-coordinate ion is To maintain electroneutrality, oxygen vacancies (Fe') are created. Zr / Ti -V O The spontaneous polarization of the defect dipole moment leads to the formation of oxygen vacancy surfaces, thereby restricting domain wall movement, which is beneficial for enhancing Q. m And reduce tanδ. For example, at 0.90Pb 0.95 Sr 0.05 (Zr 0.52 Ti 0.48 O3-0.03Pb(Fe) 2 / 3 W 1 / 3 O3-0.07Pb(Mn) 1 / 3 Nb 2 / 3 The mechanical quality factor Q of Fe2O3 doped with O3 m This will increase the dielectric loss to 1839 and reduce it to 0.54% (Journal of Electronic Materials 44(1)(2014)258-262). Pb modified with Fe2O3... 0.98 Sr 0.02 (Mn 1 / 3 Sb 2 / 3 ) 0.05 Zr 0.48 Ti 0.47 O3 piezoelectric ceramics exhibit low dielectric loss of 0.295% (Ceramics International 43(14)(2017)10866-10872). Furthermore, 0.125Pb(Zn) doped with Fe2O3 is also used. 1 / 3 Nb 2 / 3 O3-0.075Pb(Mn) 1 / 3 Nb 2 / 3 O3-0.8Pb(Zr) 0.48 Ti 0.52Introducing O3 can improve the quality factor to 1738 and reduce the dielectric loss to 0.4% (Journal of the American Ceramic Society 106(11)(2023)6868-6878.). More importantly, due to the domain pinning effect, acceptor doping can also improve the thermal stability of Pb(Zr,Ti)O3-based hard piezoelectric materials. For example, by introducing oxygen vacancies, the thermal stability of Pb(Ni,Nb)O3-PbZrO3-PbTiO3 ceramics can be improved from 25℃ to 90℃. 33 The change was less than 6%, 0.04BiYbO3-0.96Pb(Zr) 0.469 Ti 0.531 )O3 ceramics d 33 The change was less than 10% (Journal of Materials Science 58(24)(2023)10073-10084. Journal of the American Ceramic Society 106(3)(2022)1970-1980).

[0006] Excessive oxygen vacancies can significantly suppress domain wall movement in ferroelectrics, thereby inhibiting the piezoelectric response. Conversely, lead vacancies can reduce the internal stress of ceramics and decrease the space charge of domain walls, thus increasing domain wall mobility and improving the strain of the piezoelectric lattice. Therefore, for acceptor-doped hard high-power piezoelectric ceramics, designing a method to balance the content of oxygen and lead vacancies is crucial. Yb₂O₃ possesses both "hard" and "soft" properties, which can enhance the electromechanical properties of hard piezoelectric materials. This is because Yb 3+ The 6-coordination radius of the ion is 8 coordination radius is Its atomic radius is greater than that of Pb 2 + Small, Pb 2+ The 12 coordination radius is However, it is larger than the values ​​of various 6-coordinate B-site ions: Mg 2+ Nb 5+ Mn 2+ Mn 3+ Sb 5+ Zr 4+ Ti 4+ For example, Yb-doped 0.05Pb(Mn) 1 / 3 Sb 2 / 3O3-0.95Pb(Zr) 0.52 Ti 0.48 O3 ceramics possess excellent piezoelectric properties, such as d 33 =390pC / N,Q m =800,k p =0.61,ε r =1380(Ceramics International 34(8)(2008)2067-2072.). Ryu et al. found that Yb2O3 can effectively increase the vibration velocity of Pb(Zr,Ti)O3-Pb(Mn,Nb)O3 ceramics (Japanese Journal of Applied Physics 42(Part 1, No.3)(2003)1307-1310).

[0007] However, although it is known in the existing technology that adding Fe2O3 or Yb2O3 to PZT-based hard high-power piezoelectric ceramics can optimize their piezoelectric properties, the PZT-based hard high-power piezoelectric ceramics with the above components still have problems such as insufficient piezoelectric charge coefficient and poor temperature stability, which hinder the realization of high vibration velocity and stability of piezoelectric ceramics. Therefore, exploring a new type of lead zirconate titanate-based high-power piezoelectric ceramic and its preparation method to meet the requirements of high piezoelectric coefficient, high quality factor, low dielectric loss, high electromechanical coupling coefficient and excellent temperature stability is an important technical problem that urgently needs to be solved. Summary of the Invention

[0008] Pb(Mn 1 / 3 Sb 2 / 3 PMS-PZT-based piezoelectric ceramics possess high mechanical quality factors and low dielectric loss (tanδ), making them one of the most important systems for high-power applications. However, the insufficient piezoelectric charge coefficient and poor temperature stability of PMS-PZT-based piezoelectric ceramics hinder the achievement of high vibrational velocities and stability. To address the issues of low piezoelectric coefficients and the inability to simultaneously meet specific electrical performance requirements in PMS-PZT-based high-power piezoelectric ceramics, this invention provides a novel PMS-PZT high-power piezoelectric ceramic with high piezoelectric coefficient, high quality factor, low dielectric loss, high electromechanical coupling coefficient, and excellent temperature stability, along with its preparation method.

[0009] In a first aspect, the present invention provides a novel PMS-PZT-based high-power piezoelectric ceramic, wherein the chemical composition of this novel PMS-PZT-based high-power piezoelectric ceramic is 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb0.95 Sr 0.05 (Zr 0.48 Ti 0.52 The compound is ⇌ Fe₂O₃ + xFe₂O₃ & Yb₂O₃ (0 < x ≤ 0.8) mol%, abbreviated as xFY-PMN-PMS-PSZT, where Fe₂O₃:Yb₂O₃ = 1:1, and 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 O3 is abbreviated as PMN-PMS-PSZT.

[0010] The xFY-PMN-PMS-PSZT high-power piezoelectric ceramic innovatively incorporates Pb(Mn) in the PMS-PZT base. 1 / 3 Sb 2 / 3 O3-Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 Using O3(PMS-PSZT) ceramic as the matrix, a "soft" and "hard" co-doping strategy is adopted to enhance the tunability of its properties: First, Fe is synergistically selected, which has ferroelectric activity and can replace oxygen octahedral B-site elements in the perovskite structure to generate oxygen vacancies. 2+ / Fe 3+ Yb ions can, secondly, replace oxygen octahedral B-site or A-site elements in the PSZT-PMS-based perovskite structure to generate lead or oxygen vacancies. 3+ Ions, thus forming a double vacancy formed by the coupling of lead and oxygen vacancies, which plays a regulatory role in domain wall energy. Its Fe 2+ / Fe 3+ / Yb 3+ Ions are used to modulate the tetragonal structure of PMN-PMS-PSZT high-power piezoelectric ceramics, thereby increasing the tetragonality of the material and improving its piezoelectric properties.

[0011] In xFY-PMN-PMS-PSZT ceramics, the synergistic effect of dual vacancies (lead and oxygen vacancies coupled together) effectively improves the piezoelectricity of PSZT-PMS-based perovskite piezoelectric ceramics, optimizing their quality factor, dielectric loss, and electromechanical coupling coefficient. Furthermore, the pinning effect of oxygen vacancies on the 90° domain structure is beneficial to the temperature stability of the PMN-PMS-PSZT-based perovskite structure, providing a new approach for the application of piezoelectric ceramics in high-power piezoelectric devices.

[0012] This invention utilizes the ability of Fe2O3 & Yb2O3 doping to diversify atomic substitution and replacement, and introduces double vacancies that couple lead vacancies and oxygen vacancies through double ion substitution alone, thereby obtaining high-power PSZT-PMS-based piezoelectric ceramics with high voltage coefficient, high quality factor, low dielectric loss, high electromechanical coupling coefficient, large dielectric constant and excellent temperature stability.

[0013] Preferably, the novel xFY-PMN-PMS-PSZT high-power piezoelectric ceramic, when x = 0.4 mol%, has a room temperature piezoelectric coefficient of 348 pC / N, a mechanical quality factor of 1501, a low dielectric loss of 0.35%, a high electromechanical coupling coefficient of 53%, and a piezoelectric coefficient variation rate of less than 10% in the range of 25℃-210℃.

[0014] Secondly, the present invention provides a method for preparing the novel PSZT-PMS-based high-power piezoelectric ceramic as described in any of the above claims. The preparation method includes: using PbO (99.9%), MgO (99.99%), Nb2O5 (99.99%), MnO2 (99%), Sb2O3 (99.9%), SrCO3 (99.95%), ZrO2 (99%), TiO2 (99%), Fe2O3 (99.9%), and Yb2O3 (99.99%) as raw materials according to the corresponding stoichiometric ratios, mixing the raw materials, and synthesizing them at 800°C for 2-4 hours to obtain ceramic powder; and sintering the ceramic powder at 1200°C for 2 hours to obtain the novel PSZT-PMS-based high-power piezoelectric ceramic. This preparation method uses a solid-state reaction to prepare xFY-PMN-PMS-PSZT high-power piezoelectric ceramics.

[0015] Preferably, the particle size of the ceramic powder is 1–2 μm.

[0016] Preferably, the mixing method is wet ball milling, wherein the mass ratio of raw material:milling media:water is 1:(1.2-1.8):(0.5-0.9), and the mixing time is 2-6 hours. In some technical solutions, the milling media is agate balls.

[0017] Preferably, the preparation method further includes: adding a binder to the ceramic powder before sintering to granulate, pressing and molding to obtain a ceramic green body, and then sintering the ceramic green body; preferably, the amount of binder added is 4-8 wt.% of the ceramic powder; more preferably, the binder is polyvinyl alcohol.

[0018] Preferably, the descaling conditions are to heat to 600-800°C at a heating rate of no more than 2°C / min and hold at that temperature for no more than 3 hours.

[0019] Preferably, the preparation method further includes: silvering, drying and calcining the novel xFY-PMN-PMS-PSZT high-power piezoelectric ceramic, and then applying electrodes for polarization.

[0020] Preferably, the silver burning conditions are holding at 700-800°C for less than 30 minutes; the polarization conditions are polarization at 100-140°C at 4-6 kV / mm for 15-30 minutes.

[0021] Preferably, before adding the binder for granulation, the ceramic powder is finely ground by wet ball milling and then dried, wherein the mass ratio of ceramic powder: milling media: water is 1:(1.2~1.8):(0.5~0.9), and the fine grinding time is 4~8 hours.

[0022] Beneficial effects: This invention innovatively uses Sr-doped 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 O3 is used as the matrix, and Fe is introduced to generate oxygen vacancies by replacing oxygen octahedral B-site elements in the perovskite structure. 2+ / Fe 3+ Yb ions and elements that can substitute for oxygen octahedral B-site or A-site elements in the PSZT-PMS-based perovskite structure to create lead or oxygen vacancies 3+ Ions, thus forming a dual-vacancy structure where lead and oxygen vacancies are coupled, which can regulate domain wall energy. This achieves a "soft" and "hard" co-doping strategy to enhance the tunability of its performance. Fe 2+ / Fe 3+ / Yb 3+ Ions were used to modulate the high-power piezoelectric ceramic PMN-PMS-PSZT with a tetragonal structure, achieving an unexpected technical effect of 1+1>2. This overcame the technical defects of single Fe or Yb doping in existing PMS-PZT-based piezoelectric ceramics, and successfully developed a new type of high-power piezoelectric ceramic with great commercial value. Attached Figure Description

[0023] Figure 1 In the figure, (a), (b), (c), (d), and (e) are respectively piezoelectric ceramics 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr0.05 (Zr 0.48 Ti 0.52 Scanning electron microscope (SEM) images of Fe2O3 & Yb2O3 mol% (x = 0, 0.2, 0.4, 0.6, 0.8) with O3+x.

[0024] Figure 2 (a) in the figure represents the piezoelectric ceramic 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 X-ray diffraction patterns of O3+x Fe2O3&Yb2O3 mol% (x=0,0.2,0.4,0.6,0.8), (b) is a magnified view of (a);

[0025] Figure 3 (a), (b), and (c) are piezoelectric ceramics of 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 The piezoelectric coefficient d of Fe2O3 & Yb2O3 mol% (x = 0, 0.2, 0.4, 0.6, 0.8) 33 Mechanical quality factor Q m Electromechanical coupling coefficient k p piezoelectric voltage constant g 33 The curve, dielectric constant ε r Schematic diagram of dielectric loss tanδ;

[0026] Figure 4 (a) and (b) are piezoelectric ceramics of 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 A schematic diagram of the temperature-dependent piezoelectric coefficients of Fe2O3 and Yb2O3 mol% (x = 0, 0.2, 0.4, 0.6, 0.8);

[0027] Figure 5This is a process flow diagram of the preparation process of a novel lead zirconate titanate-based high-power piezoelectric ceramic according to the present invention. Detailed Implementation

[0028] The present invention is further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention. Unless otherwise specified, all percentage contents refer to mass percentages.

[0029] Existing high-power piezoelectric ceramic materials cannot simultaneously meet the requirements of high-power piezoelectric devices in terms of overall electrical properties. Therefore, this invention proposes an innovative composition design, using Fe... 2+ / Fe 3+ / Yb 3+ Ion substitution at B-sites or A-sites introduces double vacancies coupling lead and oxygen vacancies. This effectively maintains a high mechanical quality factor while significantly improving the piezoelectricity of PSZT-PMS piezoelectric ceramics by altering their tetragonality. Furthermore, the synergistic effect of oxygen vacancy pinning domain walls optimizes the temperature stability of the ceramic's piezoelectric properties, providing a new approach for the application of lead-based perovskite piezoelectric ceramics in high-power piezoelectric devices. For details, see [link to details]. Figure 1-5 This invention discloses a novel lead zirconate titanate-based high-power piezoelectric ceramic (also known as "lead-based perovskite high-power piezoelectric ceramic") with a composition of 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 The reaction is: Fe₂O₃ + xFe₂O₃ & Yb₂O₃)mol%, where x = 0, 0.2, 0.4, 0.6, 0.8, and Fe₂O₃:Yb₂O₃ = 1:1. In some technical solutions, 0 < x ≤ 0.8. A further preferred value is 0.4 ≤ x ≤ 0.6.

[0030] In the aforementioned lead-based perovskite high-power piezoelectric ceramics, the PSZT-PMS composition with a tetragonal structure is selected as the matrix. At the same time, a strategy of simultaneously introducing "donor" and "acceptor" doping at the A and B sites is adopted to enhance the performance tunability, thereby obtaining a high-power piezoelectric structure with improved tetragonality and oxygen vacancy pinning 90° domain structure, thus improving piezoelectric, ferroelectric, dielectric and piezoelectric stability properties.

[0031] Compared with PMN-PMS-PSZT piezoelectric ceramics, this invention introduces Fe 2+ / Fe 3+ / Yb 3+The ions, with superior ferroelectric activity compared to Zr and Ti, can generate larger B-site ion shifts. The introduction of Fe and Yb alters the tetragonality of the material, increasing the electric dipole moment and thus the piezoelectric coefficient. Furthermore, it changes the orbital hybridization of the B-site cations and oxygen atoms, thereby altering electronic properties and optimizing the macroscopic electrical properties of the material, such as reducing dielectric loss. Simultaneously, Yb... 3+ Mg replacing the A site 2+ This creates lead vacancies. Lead vacancies facilitate domain wall movement, enhance intrinsic effects, and thus improve piezoelectric properties. Secondly, Fe... 2+ / Fe 3+ and Yb 3+ The substitution of B sites increases the number of oxygen vacancies in the material, which is beneficial to the pinning effect of ferroelectric domains, effectively regulating its piezoelectric coefficient and mechanical quality factor, while making the 90° domain structure more stable, thus obtaining a high-power piezoelectric material with excellent comprehensive performance.

[0032] This invention employs the above-mentioned composition and adjusts the concentration of defective dipoles to improve the piezoelectric coefficient of the piezoelectric ceramic while ensuring a high mechanical quality factor (above 1500) and low dielectric loss (0.35%). Simultaneously, it achieves excellent temperature stability, with the piezoelectric coefficient varying by less than 10% within the range of 25℃-210℃. This meets the requirements of high-power devices for high-power piezoelectric ceramic materials and strongly promotes their application. In some examples, the high-power piezoelectric ceramic has a piezoelectric coefficient of 348 pC / N, a mechanical quality factor of 1501, and a dielectric loss of 0.35%. This is comparable to undoped PSZT-PMS piezoelectric ceramics (d... 33 Compared to (244 pC / N, tanδ = 0.7%), the overall performance of the material is significantly improved.

[0033] The present invention also discloses the above-mentioned Pb 0.95 Sr 0.05 Zr 0.52 Ti 0.48 O3-PbMn 1 / 3 Sb 2 / 3 O3-PbFe 2 / 3 W 1 / 3 The preparation process of O3 piezoelectric ceramics specifically includes batching, mixing, synthesis, fine grinding, molding, plasticizing, and sintering.

[0034] In some examples, the preparation method of the perovskite-structured high-power piezoelectric ceramic material may include the following steps: Step (a), weighing PbO, MgO, Nb2O5, MnO2, Sb2O3, SrCO3, ZrO2, TiO2, Fe2O3, and Yb2O3 powders according to stoichiometric ratios, and synthesizing 0.05Pb(MgO) by wet planetary ball milling. 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 O3+x Fe2O3&Yb2O3 mol%, where x=0,0.2,0.4,0.6,0.8 ceramic powder.

[0035] In this wet planetary ball mill, the materials are mixed for 2-6 hours at a mass ratio of raw material: milling media: water = 1:(1.2-1.8):(0.5-0.9). The milling media can be agate balls. The synthesis conditions are as follows: synthesis at 600-900℃ for 2-4 hours. Preferably, the temperature is increased to 700-900℃ at a heating rate not exceeding 2℃ / min, held for 2-3 hours, and then cooled to room temperature in the furnace to obtain the synthesized product.

[0036] After synthesis, the synthesized material can be subjected to secondary planetary ball milling and drying. Fine milling is performed for 4–8 hours at a mass ratio of synthesized material: milling media: water = 1:(1.2–1.8):(0.5–0.9). Agate balls can be used as the milling media. After secondary planetary ball milling, the material is dried at 100–150°C.

[0037] Step (b) involves adding a binder to the ceramic powder, granulating it, aging it, pressing it into shape, and then heating it to remove excess plastic, thus obtaining a ceramic green body. In some examples, the binder may be polyvinyl alcohol (PVA). The amount of binder added may be 4–8 wt.% of the ceramic powder. Furthermore, the removal conditions may be: heating to 600–800°C at a heating rate not exceeding 2°C / min, and holding at that temperature for no more than 3 hours.

[0038] In step (c), the ceramic green body is placed in a (small) high-temperature furnace. To reduce the volatilization of lead oxide at high temperatures, the ceramic green body is covered with a powder of the corresponding component obtained in step (a). Then, it is sintered under certain conditions to obtain the ceramic sheet. The sintering conditions may be: heating to 1000–1200°C at a heating rate not exceeding 2°C / min, holding at that temperature for 1–3 hours, and then cooling to room temperature with the furnace.

[0039] Step (d) involves processing the sintered ceramic sheet to the required size, ultrasonically cleaning it, screen printing silver, drying it, firing it with silver, and then polarizing it with electrodes to obtain the high-temperature piezoelectric ceramic material. The firing conditions can be 700–800℃ for less than 60 minutes. Additionally, the polarization conditions can be 100–140℃, 4–6 kV / mm, and polarization for 15–30 minutes.

[0040] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0041] Comparative Example 1

[0042] 1. 0.05Pb(Mg) was prepared by solid-state sintering. 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 High-power piezoelectric ceramic (Fe2O3:Yb2O3 mol%), where Fe2O3:Yb2O3 = 1:1 and x is 0. PbO, MgO, Nb2O5, MnO2, Sb2O3, SrCO3, ZrO2, and TiO2 powders were used as raw materials. The materials were weighed according to stoichiometric ratios and mixed using a wet ball mill at a mass ratio of raw materials:grinding media:water = 1:1.5:0.7 for 6 hours to ensure homogeneity. The mixed raw materials were dried at 120℃, passed through a 40-mesh sieve, and shaped under 3MPa pressure. The temperature was then increased to 850℃ at a rate of 2℃ / min and held for 2 hours to synthesize the desired ceramic powder.

[0043] 2. Grind the ceramic powder synthesized in step 1, pass it through a 40-mesh sieve, and then finely grind it using a wet ball mill. Mix the ceramic powder, grinding media, and water at a mass ratio of 1:1.5:0.6 for 6 hours to ensure uniform mixing, resulting in powder with a particle size between 1 and 3 μm. Dry the obtained powder, add 6 wt.% PVA binder, granulate, mold under 5 MPa pressure, age for 24 hours, pass it through a 40-mesh sieve, and press it into 10 mm diameter discs under 1.3 MPa pressure. Then, heat the discs to 750°C in a low-temperature furnace and hold for 60 minutes to remove excess plastic and obtain the green body.

[0044] 3. The ceramic blank is buried in a sealed alumina crucible containing ceramic powder of the same composition, placed in a high-temperature furnace, heated to the target temperature of 1150-1200℃ at a heating rate of 2℃ / min and held for 2 hours. After cooling to room temperature in the furnace, it is taken out to obtain the desired ceramic sheet.

[0045] 4. The obtained ceramic sheet is processed to a thickness of 0.5 mm, ultrasonically cleaned, dried, and silver-coated on both sides by screen printing. The temperature is raised to 750 °C at a heating rate of 2 °C / min and held for 10 minutes. The silver is then fired, and the electrode is applied for polarization. The polarization conditions are 120 °C and 4-6 kV / mm for 20 minutes to obtain the high-temperature piezoelectric ceramic with the perovskite structure.

[0046] Example 1

[0047] 1. 0.05Pb(Mg) was prepared by solid-state sintering. 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 High-power piezoelectric ceramics (Fe2O3:Yb2O3 mol%), where Fe2O3:Yb2O3 = 1:1, and x = 0.2, i.e., Fe2O3 = 0.2 mol% and Yb2O3 = 0.2 mol%. Using PbO, MgO, Nb2O5, MnO2, Sb2O3, SrCO3, ZrO2, TiO2, Fe2O3, and Yb2O3 powders as raw materials, the materials were weighed according to stoichiometric ratio and mixed using a wet ball milling method at a mass ratio of raw materials: grinding media: water = 1:1.5:0.7 for 6 hours to ensure uniform mixing. The mixed raw materials were dried at 120℃, passed through a 40-mesh sieve, and shaped under 3MPa pressure. The temperature was then increased to 850℃ at a rate of 2℃ / min and held for 2 hours to synthesize the desired ceramic powder.

[0048] 2. Grind the ceramic powder synthesized in step 1, pass it through a 40-mesh sieve, and then finely grind it using a wet ball mill. Mix the ceramic powder, grinding media, and water at a mass ratio of 1:1.5:0.6 for 6 hours to ensure uniform mixing, resulting in powder with a particle size between 1 and 3 μm. Dry the obtained powder, add 6 wt.% PVA binder, granulate, mold under 5 MPa pressure, age for 24 hours, pass it through a 40-mesh sieve, and press it into 10 mm diameter discs under 1.3 MPa pressure. Then, heat the discs to 750°C in a low-temperature furnace and hold for 60 minutes to remove excess plastic and obtain the green body.

[0049] 3. The ceramic blank is buried in a sealed alumina crucible containing ceramic powder of the same composition, placed in a high-temperature furnace, heated to the target temperature of 1150-1200℃ at a heating rate of 2℃ / min and held for 2 hours. After cooling to room temperature in the furnace, it is taken out to obtain the desired ceramic sheet.

[0050] 4. The obtained ceramic sheet is processed to a thickness of 0.5 mm, ultrasonically cleaned, dried, and silver-coated on both sides by screen printing. The temperature is raised to 750 °C at a heating rate of 2 °C / min and held for 10 minutes. The silver is then fired, and the electrode is applied for polarization. The polarization conditions are 120 °C and 4-6 kV / mm for 20 minutes to obtain the high-temperature piezoelectric ceramic with the perovskite structure.

[0051] Example 2

[0052] Example 2 is basically the same as Example 1, except that x = 0.4.

[0053] Example 3

[0054] Example 3 is basically the same as Example 1, except that x = 0.6.

[0055] Example 4

[0056] Implementation 4 is basically the same as Implementation 1, except that x = 0.8.

[0057] Testing of the polarized ceramics: The phase structure of the piezoelectric ceramics was analyzed using a Bruker X-ray diffractometer; a ZJ-3AN / PM300 quasi-static d-ray diffractometer manufactured by the Institute of Acoustics, Chinese Academy of Sciences was used. 33 The tester measures the d of piezoelectric ceramics at room temperature. 33 The test frequency was 100Hz, with 10 samples tested per specimen, and the average value was taken. The variable-temperature piezoelectric coefficient was tested using a PMS-1000 high-temperature piezoelectric testing system manufactured by Bailibo Company. The impedance coefficient of the piezoelectric ceramic was tested using a 4294A manufactured by Agilent Technologies. The test results of various performance characteristics of the high-temperature piezoelectric ceramic of this invention are shown in Table 1.

[0058] Table 1 Performance Test Table for Piezoelectric Ceramic Materials

[0059]

[0060]

[0061] As can be seen from Table 1, d 33 The value of Q first increases and then decreases as x increases, while the depolarization temperature gradually increases as x increases. m The value of Q first increases and then decreases with increasing doping concentration, maintaining a relatively high value at x = 0.4. m=1501), the value of tanδ first decreases and then increases with increasing doping concentration, and remains low at x=0.4 (tanδ=0.35%). The electromechanical coupling coefficient first increases and then decreases with increasing doping concentration, and has a high value at x=0.4 (k p =53%). The dielectric constant increases and then decreases with increasing doping concentration, reaching a maximum value of 1841 at a doping concentration of 0.6. The rate of change of the piezoelectric voltage constant decreases with increasing doping concentration; at a doping concentration of 0.6, the rate of change is only 0.16%-3.6% in the range of 25℃ to 210℃. When x is controlled below 0.6, the tetragonality, defect concentration, and performance of the ceramic can be controllably adjusted by only adjusting Fe2O3 & Yb2O3 to meet the requirements of high-power piezoelectric devices for ceramic materials (high piezoelectric coefficient, high quality factor, low dielectric loss, high electromechanical coupling coefficient, and excellent temperature stability). When the value of x is greater than 0.6, the defects in the ceramic are mainly lead vacancies, which affects the material's performance (e.g., mechanical quality factor Q). m The overall performance of piezoelectric ceramics has declined significantly.

[0062] Figure 1 Images (a), (b), (c), (d), and (e) show the surface thermal corrosion morphology of the high-power piezoelectric ceramics (x = 0, 0.2, 0.4, 0.6, 0.8) of this invention. Figure 1 It can be seen that the ceramic cross-section has relatively few pores, which indirectly indicates that the material has a high density. As x increases, the average grain size of the ceramic gradually increases from 2.65 μm to 5.75 μm, showing a significant increasing trend. This is mainly because the oxygen vacancies generated by doping have a sintering-aiding effect.

[0063] Figure 2 (a), (b), and (c) are the X-ray spectra of the high-power piezoelectric ceramics (x = 0, 0.2, 0.4, 0.6, 0.8) of this invention. Figure 2 As can be seen, the above-mentioned piezoelectric ceramic exhibits a single perovskite structure, and the splitting of the 002 peak indicates that all components exhibit a stable tetragonal phase. The diffraction peak of (002) first shifts to a higher angle, and then returns to a lower angle as the doping concentration reaches 0.6, indicating that the cell volume first increases and then decreases, indicating that the crystal structure of the material is distorted, which is conducive to the enhancement of the intrinsic effect and indicates that the piezoelectric effect is enhanced.

[0064] Figure 3Images (a), (b), and (c) show the piezoelectric strain constant, mechanical quality factor, electromechanical coupling coefficient, piezoelectric voltage constant, dielectric constant, and dielectric loss of the high-power piezoelectric ceramic (x = 0, 0.2, 0.4, 0.6, 0.8) at room temperature according to the present invention. With increasing doping concentration, the piezoelectric strain constant first increases and then decreases. At doping concentrations of 0.4 and 0.6, the piezoelectric strain constant is above 330. Furthermore, the mechanical quality factor of the material is above 1000, and the electromechanical coupling coefficient first increases and then decreases with increasing doping concentration, reaching its maximum value (k) at x = 0.4 and x = 0.6. p =53%), and the piezoelectric voltage constant reaches its maximum value when x=0.6, which is crucial for improving the energy density of high-power piezoelectrics.

[0065] The schematic diagram of the dielectric constant and dielectric loss of the high-power piezoelectric ceramic (x = 0, 0.2, 0.4, 0.6, 0.8) at room temperature is shown in the present invention. The dielectric constant increases with the increase of x, and reaches its maximum value when x = 0.6, indicating that the intrinsic dielectric is enhanced. The dielectric loss reaches its minimum value when x = 0.4 and x = 0.6, which is beneficial to reducing the heat generated during the operation of high-power devices.

[0066] Figure 4 Figures (a) and (b) show the piezoelectric strain constant and its rate of change under varying temperatures of the high-power piezoelectric ceramic (x = 0, 0.2, 0.4, 0.6, 0.8) of this invention. The figures show that the depolarization temperature increases with increasing doping concentration. Simultaneously, it can be observed that the rate of change of the piezoelectric strain constant decreases with increasing doping concentration between 25 and 210 °C, reaching a minimum at x = 0.6, indicating that the piezoelectric strain constant is very stable when the doping concentration is 0.6.

Claims

1. A method for preparing a lead zirconate titanate-based high-power piezoelectric ceramic, characterized in that, The preparation method includes: S1. Weigh the powder raw materials according to the stoichiometric ratio, and process them in a wet planetary ball mill to obtain ceramic powder. The powder raw materials include: PbO, MgO, Nb2O5, MnO2, Sb2O3, and SrCO. 3、 ZrO2, TiO2, Fe2O3 and Yb2O3 powders, wherein the stoichiometric ratio is 0.05Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.05Pb(Mn) 1 / 3 Sb 2 / 3 O3-0.9Pb 0.95 Sr 0.05 (Zr 0.48 Ti 0.52 O3 + x mol% Fe2O3+ x mol%Yb2O3, where x is an adjustment parameter, x=0.4 or 0.6; S2. Add a binder to the ceramic powder obtained in step S1, granulate it, age it, press it into a green body, and then heat and exfoliate the green body to obtain a ceramic body. S3. Place the ceramic blank obtained in step S2 into a high-temperature furnace, and cover the ceramic blank with the ceramic powder to sinter and obtain ceramic sheets. S4. The ceramic sheet is processed and then polarized to obtain the high-power piezoelectric ceramic. The processing includes a silver firing process, in which the silver firing process is held at 700~800℃ for less than 30 minutes. The polarization conditions include: maintaining the temperature at 100~140℃ and the voltage at 4~6 kV / mm, and the polarization time lasting 15~30 minutes. In step S1, the process of placing the ceramic powder in a wet planetary ball mill to obtain the ceramic powder includes: In a wet planetary ball mill, materials are first mixed according to a preset mass ratio, and then synthesized according to preset synthesis conditions. The preset mass ratio includes a ratio of raw materials, milling media, and water of 1:a:b, where the value of a ranges from 1.2 to 1.8, the value of b ranges from 0.5 to 0.9, the milling media is agate balls, and the mixing time is 2 to 6 hours. The preset synthesis conditions include: synthesizing at 600~900 ℃ for 2~4 hours.

2. The preparation method according to claim 1, characterized in that, The preset synthesis conditions include: heating to 700~900 ℃ at a heating rate not exceeding 2℃ / min, holding at that temperature for 2~3 hours, and then cooling to room temperature in the furnace.

3. The preparation method according to claim 1, characterized in that, The binder added in step S2 is polyvinyl alcohol (PVA), and the amount of binder added is 4-8 wt% of the ceramic powder. The conditions for heating and removing plastic from the green body include: heating to 600~800℃ at a heating rate not exceeding 2℃ / min, and holding at that temperature for less than 3 hours.

4. The preparation method according to claim 1, characterized in that, In step S3, the sintering conditions include: heating to 1000~1200℃ at a heating rate not exceeding 2℃ / min, holding at that temperature for 1~3 hours, and then ending the holding and cooling to room temperature with the furnace.

5. The preparation method according to claim 1, characterized in that, In step S4, the processing includes: processing the ceramic sheet into the required size, followed by ultrasonic cleaning, screen printing silver, drying and silver firing in sequence; In the silver firing process, the temperature is kept at 700~800℃ for less than 60 minutes. The polarization conditions include: maintaining the temperature at 100~140℃, maintaining the voltage at 4~6 kV / mm, and the polarization time lasting 15~30 minutes.

6. A lead zirconate titanate-based high-power piezoelectric ceramic, characterized in that, The lead zirconate titanate-based high-power piezoelectric ceramic is prepared by the preparation method described in any one of claims 1-5.

7. The high-power piezoelectric ceramic according to claim 6, characterized in that, When x = 0.4, the piezoelectric coefficient at room temperature is d. 33 =348pC / N, Mechanical Quality Factor Q m =1501, low dielectric loss tanδ=0.35%, high electromechanical coupling coefficient k p =53%, piezoelectric coefficient varies from -5% to 0.5% within the range of 25℃-210 °C; When x = 0.6, the piezoelectric coefficient at room temperature is d. 33 =330pC / N, Mechanical Quality Factor Q m =1060, low dielectric loss tanδ=0.28%, high electromechanical coupling coefficient k p =53%, and the piezoelectric coefficient varies from 0.16% to 3.6% in the range of 25℃-210 °C.

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