Method for producing lead zirconate titanate-based piezoelectric ceramics and use thereof

Abstract

This application discloses a method for preparing lead zirconate titanate-based piezoelectric ceramics and their applications. The method includes: mixing doped and modified lead zirconate titanate-based ceramic powder with a composite sintering aid, and performing a pre-sintering treatment to obtain a pre-sintered powder. The composite sintering aid comprises a first sintering aid component and a second sintering aid component. The first sintering aid component comprises one or more of Bi₂O₃, CuO, ZnO, and PbO, and the second sintering aid component comprises one or more of Li₂CO₃, B₂O₃, V₂O₅, and SiO₂. The pre-sintered powder is then subjected to hot-pressing sintering under an inactive atmosphere to obtain a sintered body. The sintered body is then subjected to sequential electrode application, electrode sintering, and polarization treatment to obtain the lead zirconate titanate-based piezoelectric ceramic. Thus, by using a composite sintering aid and pre-sintering, hot-pressing sintering of lead zirconate titanate-based piezoelectric ceramics under an inactive atmosphere without annealing is achieved, improving the stability of lead zirconate titanate-based piezoelectric ceramics in high-power applications.

Description

Technical Field

[0001] This application relates to the field of piezoelectric ceramic materials, and specifically to methods for preparing lead zirconate titanate-based piezoelectric ceramics and their applications. Background Technology

[0002] Lead zirconate titanate (Pb(Zr,Ti)O3)-based piezoelectric ceramics are widely used in piezoelectric actuators, ultrasonic transducers, sensors, and electronic ceramic devices due to their excellent piezoelectric, dielectric, and electromechanical coupling properties, and remain one of the most important piezoelectric ceramic systems. However, existing Pb(Zr,Ti)O3-based piezoelectric ceramics are typically prepared using atmospheric pressure solid-state sintering processes. These processes generally suffer from problems such as high sintering temperatures, easy volatilization of lead components, and difficulty in controlling the consistency of microstructure and properties, and require further improvement. It should be noted that the above statements are only for providing background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0003] In a first aspect of this application, a method for preparing lead zirconate titanate-based piezoelectric ceramics is proposed, comprising: Doped and modified lead zirconate titanate-based ceramic powder is mixed with a composite sintering aid and pre-sintered to obtain pre-sintered powder. The composite sintering aid includes a first sintering aid component and a second sintering aid component. The first sintering aid component includes one or more of Bi2O3, CuO, ZnO, and PbO. The second sintering aid component includes one or more of Li2CO3, B2O3, V2O5, and SiO2. The pre-sintered powder is subjected to hot pressing sintering under an inactive atmosphere to obtain a sintered body. The sintered body is subjected to an upper electrode treatment, an electrode sintering treatment, and a polarization treatment in sequence to obtain the lead zirconate titanate-based piezoelectric ceramic.

[0004] Therefore, by using composite sintering aids and pre-sintering, the sintering temperature was reduced and the density of the sintered body was increased. The high density and oxygen vacancies have a synergistic effect, thereby enabling the inactive atmosphere hot pressing sintering of lead zirconate titanate-based piezoelectric ceramics without annealing treatment, while improving the stability of lead zirconate titanate-based piezoelectric ceramics in high-power applications.

[0005] In some embodiments, the doped lead zirconate titanate-based ceramic powder includes one or more of the following types: donor-doped, acceptor-doped, equivalent-substituted, and composite-doped. Therefore, this process can be applied to a wide variety of different lead zirconate titanate-based ceramics, greatly expanding its application scope.

[0006] In some embodiments, the doping element of the doped lead zirconate titanate-based ceramic powder includes one or more of Mn, Fe, Sb, Nb, La, W, Ba, Sr, Ca, Zr, and Sn, wherein the mass fraction of the doping element in the doped lead zirconate titanate-based ceramic powder is 0.1%-1%. Therefore, the doping modification component can significantly improve various properties of the material and expand its application range.

[0007] In some embodiments, a method for providing the doped and modified lead zirconate titanate-based ceramic powder includes: mixing a raw material powder with a modifying component and subjecting it to high-temperature calcination to obtain the doped and modified lead zirconate titanate-based ceramic powder, wherein the raw material powder includes PbO, TiO2, and ZrO2, and the modifying component includes the doping element; thereby, the high-temperature calcination treatment promotes the solid-state reaction and main crystalline phase formation of the doped and modified lead zirconate titanate-based ceramic powder.

[0008] The high-temperature calcination treatment includes a first holding treatment and a second holding treatment performed sequentially. The temperature of the first holding treatment is 500℃-700℃, and the holding time is 1h-4h. The temperature of the second holding treatment is 750℃-950℃, and the holding time is 2h-8h. Therefore, by using segmented heating treatment, the grain size of the doped lead zirconate titanate-based ceramic powder can be controlled, promoting the solid-state reaction and main crystalline phase formation of the doped lead zirconate titanate-based ceramic powder, which helps to obtain doped lead zirconate titanate-based ceramic powder with uniform composition and high activity.

[0009] In some embodiments, the composite sintering aid includes a first sintering aid component and a second sintering aid component, wherein the first sintering aid component includes one or more of Bi2O3, CuO, ZnO, and PbO; and the second sintering aid component includes one or more of Li2CO3, B2O3, V2O5, and SiO2.

[0010] Based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the composite sintering aid includes 0.05%-1.5% of the first sintering aid component and 0.05%-1.5% of the second sintering aid component.

[0011] Therefore, the composite sintering aid composed of the first and second sintering aid components can complement each other during hot pressing in an inactive atmosphere: the first sintering aid component promotes liquid phase formation and interparticle wetting, improving particle rearrangement and pore removal efficiency; the second sintering aid component lowers the local reaction temperature and improves the powder's reactivity, while mitigating the accumulation of grain boundary glass phase, increased dielectric loss, or decreased piezoelectric properties caused by excessive single low-melting-point components. The combination of these two components enables the sintered body to achieve higher density at lower sintering temperatures and maintains good polarization and piezoelectric properties without annealing.

[0012] In some embodiments, the temperature of the pre-sintering treatment is 500℃-1000℃, and the holding time of the pre-sintering treatment is 1h-10h. Thus, by promoting the pre-decomposition, pre-reaction, and uniform distribution of the composite sintering aid on the surface of the doped and modified lead zirconate titanate-based ceramic powder particles, the gas generated by the sudden decomposition of carbonates or low-melting-point components during hot pressing sintering is reduced. Simultaneously, the formation of closed pores, local enrichment, and grain boundary defects is reduced, lowering the risk of component segregation. This, in turn, improves the densification stability, polarization success rate, and electrical performance consistency of hot pressing sintering under an inactive atmosphere.

[0013] In some embodiments, the process further includes: performing a cooling treatment after the pre-sintering treatment, wherein the cooling treatment has a cutoff temperature of 500℃-700℃ and a cooling rate of no more than 10℃ / min. This prevents the block material from cracking or the powder from developing internal stress due to excessive temperature differences, which could affect subsequent processing.

[0014] In some embodiments, the hot-pressing sintering treatment is performed at a temperature of 800°C-1000°C for 10-120 minutes; and / or at a pressure of 10 MPa-60 MPa. Thus, through hot-pressing sintering, denser and higher-performance ceramics can be obtained at lower temperatures than conventional atmospheric pressure sintering (typically >1100°C).

[0015] In a second aspect of this application, a lead zirconate titanate-based piezoelectric ceramic prepared by the aforementioned method is provided. Thus, the ceramic product possesses all the features and advantages of the aforementioned method, which will not be elaborated further here.

[0016] In a third aspect, this application proposes the application of lead zirconate titanate-based piezoelectric ceramics prepared by the aforementioned method in piezoelectric actuators, ultrasonic transducers, piezoelectric sensors, piezoelectric actuators, and electronic ceramic devices. Therefore, the piezoelectric actuators, ultrasonic transducers, piezoelectric sensors, piezoelectric actuators, and electronic ceramic devices possess all the features and advantages of the aforementioned method, which will not be elaborated further here. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating the preparation process of the lead zirconate titanate-based piezoelectric ceramic in this application; Figure 2 This is a flowchart illustrating the preparation process of the doped and modified lead zirconate titanate-based ceramic powder used in this application. Detailed Implementation

[0018] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0020] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0021] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0022] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] In the description of this application, "multiple" means two or more.

[0024] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0025] In this application, the order in which the steps are written does not imply a strict execution order and does not limit the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0026] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0027] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0028] Existing lead zirconate titanate-based piezoelectric ceramics are typically prepared using atmospheric pressure solid-state sintering, which suffers from problems such as high sintering temperatures, easy volatilization of lead components, and difficulty in controlling the consistency of microstructure and properties. Hot pressing sintering, on the other hand, can apply external pressure simultaneously during heating, thereby promoting particle rearrangement, material migration, and porosity elimination, and is an effective method to improve ceramic density and reduce sintering temperature.

[0029] Hot pressing sintering, which applies external pressure during heating to promote particle rearrangement, material migration, and porosity elimination, is considered an effective method to improve ceramic density and reduce sintering temperature. However, high temperature and high pressure can easily cause the sample discs of lead zirconate titanate-based piezoelectric ceramics to be crushed and lead to precipitation, making it difficult to achieve. Adding sintering aids can effectively reduce the sintering temperature, but it faces the following problems: on the one hand, a single sintering aid is prone to insufficient densification, inadequate grain bonding, increased leakage current, difficulty in polarization, or loss of piezoelectric properties; on the other hand, sintering aids are prone to decomposition during heating to generate gas, forming closed pores.

[0030] Hot pressing sintering is typically performed in an inactive atmosphere to ensure the quality of the sintered body. Sintering in an inactive atmosphere often relies on subsequent annealing to address the problem of oxygen vacancy defect accumulation, making the experimental process complex, resource-intensive, and labor-intensive. These limitations make it difficult to simultaneously meet the requirements of low-temperature densification sintering, anneal-free polarization, and performance retention.

[0031] In this application, by using composite sintering aids and pre-sintering, the sintering temperature is reduced and the density of the sintered body is increased. The high density and oxygen vacancies have a synergistic effect, thereby enabling the non-active atmosphere hot pressing sintering of lead zirconate titanate-based piezoelectric ceramics without annealing treatment, while improving the stability of lead zirconate titanate-based piezoelectric ceramics in high-power applications.

[0032] In a first aspect of this application, a method for preparing lead zirconate titanate-based piezoelectric ceramics is proposed, with reference to... Figure 1 ,include: S10: The doped and modified lead zirconate titanate-based ceramic powder is mixed with a composite sintering aid and pre-sintered to obtain pre-sintered powder.

[0033] In some embodiments, the doped lead zirconate titanate-based ceramic powder includes one or more of donor-doped, acceptor-doped, equivalent substitution, and composite-doped types, thereby making it applicable to a variety of different lead zirconate titanate-based ceramics and greatly expanding the application range of this process.

[0034] In some embodiments, the doping elements of the doped lead zirconate titanate-based ceramic powder include one or more of Mn, Fe, Sb, Nb, La, W, Ba, Sr, Ca, Zr, and Sn. Acceptor doping elements such as Mn and Fe are beneficial for improving the mechanical quality factor and reducing losses, thus facilitating the application of high-power piezoelectric devices; donor doping elements such as Nb, La, and W are beneficial for improving the piezoelectric constant and electromechanical coupling performance, thus facilitating the application of high-sensitivity devices; elements such as Ba, Sr, and Ca can be used to adjust the Curie temperature, lattice parameters, and phase structure of the material; Zr is beneficial for adjusting the Zr / Ti ratio and phase structure, thereby improving the piezoelectric and electromechanical coupling performance of the material; Sb is beneficial for adjusting lattice defects and improving the electrical stability and mechanical quality factor of the material; Sn is beneficial for adjusting the lattice structure and sintering behavior, thereby improving the temperature stability and dielectric properties of the material.

[0035] In some embodiments, the mass fraction of the dopant element in the doped lead zirconate titanate-based ceramic powder is 0.1%-1%, thereby significantly improving various properties of the material and expanding its application range through the doping modification component.

[0036] As an example, the mass fraction of the dopant element in the doped lead zirconate titanate-based ceramic powder can be any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, or a range between any two.

[0037] In some embodiments, the composite sintering aid includes a first sintering aid component and a second sintering aid component, wherein the first sintering aid component includes one or more of Bi2O3, CuO, ZnO, and PbO; and the second sintering aid component includes one or more of Li2CO3, B2O3, V2O5, and SiO2.

[0038] As an example, composite sintering aids can include Bi2O3 and Li2CO3. Thus, their synergistic effect can effectively reduce the sintering temperature, promote densification, and improve grain development, while also taking into account the piezoelectric properties and sintering stability of the material.

[0039] In some embodiments, based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the composite sintering aid includes 0.05%-1.5% of the first sintering aid component. Thus, by adding an appropriate amount of the first sintering aid component, liquid phase formation and interparticle wetting can be promoted, improving particle rearrangement and pore removal efficiency.

[0040] As an example, based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the mass fraction of the first sintering aid component can be any one of 0.05%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, or 1.5%, or a range between any two.

[0041] In some embodiments, based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the composite sintering aid includes 0.05%-1.5% of the second sintering aid component. Thus, by adding an appropriate amount of the second sintering aid component, the local reaction temperature is reduced and the powder reactivity is improved, while mitigating the accumulation of grain boundary glass phase, increased dielectric loss, or decreased piezoelectric properties caused by excessive amounts of a single low-melting-point component.

[0042] As an example, based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the mass fraction of the second sintering aid component can be any one of 0.05%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, or 1.5%, or a range between any two.

[0043] A composite sintering aid consisting of a first sintering aid component and a second sintering aid component can achieve a complementary effect during hot pressing in an inactive atmosphere. The resulting lead zirconate titanate-based piezoelectric ceramics can achieve higher density at lower sintering temperatures and maintain good polarization and piezoelectric properties under annealing-free conditions. Compared to adding only one single sintering aid component, the composite formulation can simultaneously improve density and d... 33 k p Maximum vibration velocity and Q m And reduce dielectric loss.

[0044] Q m Q is the mechanical quality factor, a dimensionless parameter used to characterize the degree of mechanical energy loss of a piezoelectric oscillator in the resonant state. m The higher the value, the lower the mechanical loss, which is generally more beneficial for high-power applications.

[0045] d 33 d is the piezoelectric constant, used to characterize the electromechanical conversion capability of piezoelectric materials in the polarization direction. 33 The higher the value, the stronger the piezoelectric response capability of the material.

[0046] k p k is the planar electromechanical coupling coefficient, used to characterize the conversion efficiency between mechanical energy and electrical energy in piezoelectric materials. p The higher the value, the stronger the electromechanical coupling capability.

[0047] Maximum vibration velocity refers to the maximum vibration velocity that a piezoelectric ceramic can achieve under certain driving conditions. Its value can reflect the material's large signal driving capability and energy conversion performance to a certain extent.

[0048] In some embodiments, the pre-sintering treatment further includes a ball milling treatment and a drying and grinding treatment. The ball milling media for the first ball milling treatment includes one or more of zirconia balls, alumina balls, and agate balls, and the solvent includes one or more of anhydrous ethanol, isopropanol, and deionized water.

[0049] In some embodiments, the ball milling process is performed for 8-36 hours, optionally 12-24 hours. Therefore, by controlling the ball milling time, it is helpful to achieve thorough mixing of the doped lead zirconate titanate-based ceramic powder and the composite sintering aid.

[0050] As an example, the time for one ball milling process can be any one of 8h, 12h, 16h, 20h, 22h, 24h, 28h, 32h, 36h or a range between any two.

[0051] In some embodiments, the temperature of the pre-sintering treatment is 500℃-1000℃, and optionally, 800℃-900℃.

[0052] As an example, the temperature of the pre-sintering treatment can be any one of 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃ or a range between any two.

[0053] In some embodiments, the heat preservation time of the pre-sintering treatment is 1h-10h, or optionally 3h-8h.

[0054] As an example, the holding time for the pre-sintering treatment can be any one of 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, or 10h, or a range between any two.

[0055] By controlling the temperature and holding time of the pre-sintering treatment, it is helpful to promote the pre-decomposition, pre-reaction and uniform distribution of the composite sintering aid on the surface of the doped and modified lead zirconate titanate-based ceramic powder particles. This reduces the gas generated by the sudden decomposition of carbonates or low-melting-point components during hot pressing sintering, while also reducing the formation of closed pores, local enrichment and grain boundary defects, thus reducing the risks. This improves the densification stability, polarization success rate and electrical performance consistency of hot pressing sintering under an inactive atmosphere.

[0056] In some embodiments, the method further includes: performing a cooling treatment after the pre-sintering treatment, wherein the cooling treatment has a cutoff temperature of 500°C-700°C. As an example, the cutoff temperature of the cooling treatment can be any one of 500℃, 600℃, 700℃ or a range between any two, optionally 550℃-650℃.

[0057] In some embodiments, the heat preservation time of the cooling treatment is no more than 2 hours.

[0058] As an example, the heat preservation time of the cooling treatment can be any one of 0h, 1h, 2h or a range between any two.

[0059] In some embodiments, the cooling rate of the cooling process is no more than 10°C / min.

[0060] As an example, the cooling rate of the cooling process can be any one of 0℃ / min, 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, or a range between any two.

[0061] Therefore, by controlling the cooling process's cutoff temperature, holding time, and cooling rate, it is possible to prevent excessive temperature differences from causing the block material to crack or the powder to generate internal stress, thus affecting subsequent processing.

[0062] In some embodiments, the process further includes a secondary ball milling process, a drying process, and a sieving process after the cooling process. The ball milling media for the secondary ball milling process includes one or more of zirconia balls, alumina balls, and agate balls, and the solvent includes one or more of anhydrous ethanol, isopropanol, or deionized water.

[0063] In some embodiments, the secondary ball milling process takes 8-36 hours, or optionally 12-24 hours.

[0064] As an example, the time for the secondary ball milling process can be any one of 8h, 12h, 16h, 20h, 22h, 24h, 28h, 32h, and 36h, or a range between any two.

[0065] In some embodiments, the mesh size of the sieving process is an 80-200 mesh sieve. As an example, the mesh size of the sieving process can be any one of 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, or 200 mesh, or a range between any two.

[0066] Therefore, by cooling and sieving, a more uniformly distributed powder with a finer particle size can be obtained for sintering.

[0067] In some embodiments, a method for providing the doped and modified lead zirconate titanate-based ceramic powder is described in reference to... Figure 2 ,include: S100: The raw material powder and the modified component are mixed and subjected to ball milling and drying grinding to obtain a mixed powder.

[0068] In some embodiments, the raw material powder includes PbO, TiO2 and ZrO2. Therefore, by using high-purity raw material powder, it is beneficial to accurately control the stoichiometric ratio of each element and reduce the influence of impurities, thereby improving the piezoelectric performance and stability of lead zirconate titanate-based piezoelectric ceramics.

[0069] In some embodiments, the modified component includes the dopant element, thereby contributing to improved chemical stability and operational safety of the modification process.

[0070] In some embodiments, the milling media for the primary milling process includes one or more of zirconia balls, alumina balls, and agate balls, and the solvent includes one or more of anhydrous ethanol, isopropanol, or deionized water.

[0071] In some embodiments, the time for the first ball milling process is 8h-36h, optionally 12h-24h. Thus, by controlling the time of the first ball milling process, thorough mixing of the raw material powder and the modified components is achieved.

[0072] As an example, the time for one ball milling process can be any one of 8h, 12h, 16h, 20h, 22h, 24h, 28h, 32h, 36h or a range between any two.

[0073] S200: The mixed powder is subjected to high-temperature calcination, followed by secondary ball milling, drying, and sieving to obtain the doped and modified lead zirconate titanate-based ceramic powder.

[0074] In some embodiments, the high-temperature calcination treatment includes a first heat preservation treatment and a second heat preservation treatment performed sequentially.

[0075] In some embodiments, the temperature of the first heat preservation treatment is 500℃-700℃. As an example, the temperature of the first heat preservation treatment can be any one of 500℃, 600℃, and 700℃ or a range between any two.

[0076] In some embodiments, the duration of the first heat preservation treatment is 1-4 hours. For example, the duration of the first heat preservation treatment can be any one of 1 hour, 2 hours, 3 hours, and 4 hours, or a range between any two.

[0077] Thus, by controlling the temperature and time of the first heat preservation treatment, adsorbed water and organic residues are eliminated and precursor decomposition is promoted. In some embodiments, the temperature of the second heat preservation treatment is 750°C-950°C. As an example, the temperature of the second heat preservation treatment can be any one of 750°C, 850°C, and 950°C, or a range between any two.

[0078] In some embodiments, the duration of the second heat preservation treatment is 2h-8h. For example, the duration of the second heat preservation treatment can be any one of 2h, 6h, and 8h, or a range between any two.

[0079] Thus, controlling the temperature and time of the second heat treatment promoted the formation of the lead zirconate titanate perovskite main phase. The segmented heating treatment, by controlling the grain size, helps to obtain powder with uniform composition and high activity, while promoting the solid-state reaction and main crystalline phase formation of the doped and modified lead zirconate titanate-based ceramic powder.

[0080] In some embodiments, the milling media for the secondary ball milling process includes one or more of zirconia balls, alumina balls, and agate balls, and the solvent includes one or more of anhydrous ethanol, isopropanol, or deionized water.

[0081] In some embodiments, the secondary ball milling process is carried out for 8 hours to 36 hours, optionally 12 hours to 24 hours. Thus, by controlling the duration of the secondary ball milling process, the calcined agglomerates are broken up and the uniformity of the powder is improved.

[0082] As an example, the time for the secondary ball milling process can be any one of 8h, 12h, 16h, 20h, 22h, 24h, 28h, 32h, and 36h, or a range between any two.

[0083] In some embodiments, the sieving process uses an 80-200 mesh sieve. Thus, through sieving, effective classification and separation of powder particle size are achieved, thereby removing large particles and agglomerates and improving the fineness of the powder.

[0084] As an example, the mesh size of the sieving process can be any one of 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, 200 mesh, or a range between any two.

[0085] S20: Under an inactive atmosphere, the pre-sintered powder is subjected to hot pressing sintering treatment to obtain a sintered body.

[0086] In some embodiments, before hot pressing and sintering, the process further includes molding the pre-sintered powder. The mold used for molding is made of graphite. This allows subsequent forming and sintering to be completed simultaneously, simplifying the process. Furthermore, the high-temperature resistance and easy demolding properties of graphite facilitate the production of piezoelectric ceramics with higher density and superior performance.

[0087] In some embodiments, the inactive atmosphere includes one or more of an inert gas and nitrogen, and optionally argon. This serves to prevent lead volatilization and oxidation of the pre-sintered powder.

[0088] In some embodiments, the temperature of the hot pressing sintering process is 800℃-1000℃.

[0089] As an example, the temperature of the hot pressing sintering process can be any one of 800°C, 900°C, and 1000°C, or a range between any two. In some embodiments, the hot pressing sintering process takes 10-120 minutes.

[0090] As an example, the hot pressing sintering time can be any one of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, or 120 min, or a range between any two.

[0091] In some embodiments, the pressure of the hot pressing sintering process is 10MPa-60MPa.

[0092] As an example, the pressure of the hot pressing sintering process can be any one of 10MPa, 20MPa, 30MPa, 40MPa, 50MPa, 60MPa or a range between any two.

[0093] Therefore, by controlling the temperature, time, and pressure of hot-pressing sintering in an inactive atmosphere, denser and higher-performance ceramics were obtained at lower temperatures than traditional atmospheric pressure sintering (typically >1100℃). Simultaneously, the omission of the annealing step allows the high density to synergistically interact with oxygen vacancies in the material, enabling it to withstand extremely high electrical and mechanical power while exhibiting minimal self-heating, high mechanical strength, and resistance to damage, significantly improving stability under high-power conditions. The omission of the annealing step also reduces the complexity of the operation process, improves efficiency, and lowers costs.

[0094] S30: The sintered body is subjected to an upper electrode treatment, an electrode sintering treatment, and a polarization treatment in sequence to obtain the lead zirconate titanate-based piezoelectric ceramic.

[0095] In some embodiments, prior to the upper electrode treatment, the sintered body undergoes surface treatment. This surface treatment further includes polishing and ultrasonic treatment. Thus, by polishing away the carbon paper on the sample surface with sandpaper and ultrasonically cleaning, the surface is cleaned to obtain a pure and well-bonded electrode layer.

[0096] In some embodiments, the upper electrode treatment is performed by coating the upper and lower surfaces of the sample with silver paste.

[0097] In some embodiments, the electrode sintering treatment temperature is 400℃-1000℃.

[0098] As an example, the temperature of the electrode calcination treatment can be any one of 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, and 1000℃, or a range between any two.

[0099] In some embodiments, the holding time for the electrode sintering treatment is 10 min to 50 min.

[0100] As an example, the holding time for the electrode sintering treatment can be any one of 10 min, 20 min, 30 min, 40 min, or 50 min, or a range between any two.

[0101] In some embodiments, the polarization treatment temperature is 100°C-150°C.

[0102] As an example, the temperature of the polarization treatment can be any one of 100°C, 130°C, and 150°C, or a range between any two.

[0103] In some embodiments, the polarization electric field of the polarization treatment is 2kV / mm-5kV / mm.

[0104] As an example, the polarization electric field of the polarization treatment can be any one of 2kV / mm, 3.5kV / mm, 5kV / mm, or a range between any two.

[0105] In some embodiments, the polarization treatment time is 10 min to 60 min.

[0106] As an example, the polarization treatment time can be any one of 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min, or a range between any two. The polarization treatment medium is silicone oil.

[0107] Therefore, by treating the top electrode, sintering the electrode, and polarizing the ceramic, the orientation of the internal domains of the piezoelectric ceramic tends to be uniform, thereby obtaining stable macroscopic piezoelectric properties. This ultimately achieved a sintering process for lead zirconate titanate-based piezoelectric ceramics without annealing steps under inactive atmosphere and hot-pressing conditions.

[0108] Electrode top treatment refers to the fabrication of a conductive electrode layer on the surface of piezoelectric ceramics through methods such as printing, sputtering, or evaporation to establish external electrical connections and enable electric field loading and signal extraction. Electrode sintering treatment refers to high-temperature heat treatment of the piezoelectric ceramics after coating with electrode materials, allowing the electrode layer to form a stable bond with the substrate. Polarization treatment refers to applying a DC electric field of a certain intensity to the piezoelectric ceramics, causing the internal electric domains to align oriented along the direction of the electric field, thereby obtaining macroscopic piezoelectric properties.

[0109] In a second aspect of this application, a lead zirconate titanate-based piezoelectric ceramic prepared by the aforementioned method is provided. Thus, the ceramic product possesses all the features and advantages of the aforementioned method, which will not be elaborated further here.

[0110] In a third aspect, this application proposes the application of lead zirconate titanate-based piezoelectric ceramics prepared by the aforementioned method in piezoelectric actuators, ultrasonic transducers, piezoelectric sensors, piezoelectric actuators, and electronic ceramic devices. Therefore, the piezoelectric actuators, ultrasonic transducers, piezoelectric sensors, piezoelectric actuators, and electronic ceramic devices possess all the features and advantages of the aforementioned method, which will not be elaborated further here.

[0111] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0112] The following specific embodiments illustrate the solution of this application. It should be noted that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application.

[0113] Example 1 1. Preparation of pre-sintered powder: The raw materials in parts by weight are as follows: 100 parts of lead zirconate titanate-based ceramic powder with Mn modification components, 0.3 parts of Bi2O3, and 0.3 parts of Li2CO3.

[0114] Lead zirconate titanate-based ceramic powder with Mn-modified components, Bi2O3, and Li2CO3 were added to a ball mill jar and ball-milled for 24 hours using anhydrous ethanol as the wet grinding medium. The ball-milled slurry was dried, ground, and then pre-sintered at 850℃ for 6 hours. The pre-sintered powder was ball-milled again for 24 hours, dried, ground, and sieved through an 80-mesh sieve.

[0115] 2. Hot pressing sintering treatment: The treated powder is loaded into a graphite mold, and the powder and the mold are separated by carbon paper. Hot pressing sintering is carried out under an argon atmosphere at 900℃ and 30MPa for 30 minutes.

[0116] 3. Electrode treatment, electrode sintering, and polarization: After sintering, the carbon layer on the sample surface is removed by grinding, and the sample is cut into standard test samples. After surface grinding, polishing, and ultrasonic cleaning, silver paste is coated on the upper and lower surfaces of the sample, and the sample is heat-treated at 550℃ for 30 min to form silver electrodes. Subsequently, the sample is polarized in a silicone oil medium at 130℃ and 4kV / mm for 30 min. The resulting sample can be silvered and polarized without annealing and exhibits good piezoelectric properties.

[0117] Test results: Q m For 1000, d 33 270 pC / N, k p The value is 0.30, and the maximum vibration velocity is 2.7 m / s.

[0118] Example 2 Example 2 is the same as Example 1, except that the lead zirconate titanate-based ceramic powder with Mn-modified components in Example 1 is replaced with lead zirconate titanate-based ceramic powder with Fe-modified components.

[0119] Test results: Q m 1080, d 33 255 pC / N, k p The value is 0.28, and the maximum vibration velocity is 2.9 m / s.

[0120] Example 3 Example 3 is the same as Example 1, except that the lead zirconate titanate-based ceramic powder with Mn-modified components in Example 1 is replaced with lead zirconate titanate-based ceramic powder with zirconium oxide-modified components.

[0121] Test results: Q m For 920, d 33 295 pC / N, k p The value is 0.33, and the maximum vibration velocity is 2.5 m / s. Example 4 Example 4 is the same as Example 1, except that 0.3 parts of Bi2O3 in Example 1 are replaced with 0.1 parts of Bi2O3.

[0122] Test results: Q m For 900, d 33 255 pC / N, k p The value is 0.27, and the maximum vibration velocity is 2.4 m / s. Example 5 Example 5 is the same as Example 1, except that 0.3 parts of Bi2O3 in Example 1 are replaced with 0.5 parts of Bi2O3.

[0123] Test results: Q m For 960, d 33 260 pC / N, k p The value is 0.29, and the maximum vibration velocity is 2.6 m / s. Comparative Example 1 Comparative Example 1 is the same as Example 1, except that 0.3 parts of Bi2O3 in Example 1 are replaced with no Bi2O3 and 0.3 parts of Li2CO3 are replaced with 0.6 parts of Li2CO3.

[0124] Test results: Q m For 820, d 33 240 pC / N, k p The value is 0.26, and the maximum vibration velocity is 2.4 m / s.

[0125] Comparative Example 2 Comparative Example 2 is the same as Example 1, except that the pre-sintering treatment in Example 1 is removed.

[0126] Test results: Q m 440, d 33 185 pC / N, k p The value is 0.19, and the maximum vibration velocity is 1.3 m / s.

[0127] Comparative Example 3 Comparative Example 3 is the same as Example 1, except that an air annealing treatment is added after hot pressing and sintering in Example 1.

[0128] Test results: Q m 460, d 33 220 pC / N, k p The value is 0.25, and the maximum vibration velocity is 1.6 m / s.

[0129] Comparative Example 4 Comparative Example 4 is the same as Example 1, except that 0.3 parts of Li2CO3 in Example 1 are replaced with no Li2CO3 and 0.3 parts of Bi2O3 are replaced with 0.6 parts of Bi2O3.

[0130] Test results: Q m It is 780, d 33 220 pC / N, k p The value is 0.23, and the maximum vibration velocity is 2.1 m / s.

[0131] The method for testing the performance of the aforementioned samples is as follows: Q m (Mechanical Quality Factor): The resonant and anti-resonant frequencies of the sample were measured using an impedance analyzer (Agilent 4294A), and the mechanical quality factor Q was calculated according to the IEEE piezoelectric standard. m .

[0132] d 33 (Piezoelectric constant): using quasi-static d 33 The tester (ZJ-6A type) is used to test the polarized sample.

[0133] K p (Planar electromechanical coupling coefficient): The resonant frequency f of the sample was measured using an impedance analyzer. r and anti-resonant frequency f a The planar electromechanical coupling coefficient k was calculated according to the IEEE standard formula. p .

[0134] Maximum vibration velocity: The surface vibration velocity of the sample under resonant conditions was measured using a laser Doppler vibrometer (Polytec PSV series), and the maximum vibration velocity under stable working conditions was recorded.

[0135] Examples 1, 2, and 3 verify that this application is applicable to a variety of different lead zirconate titanate-based ceramics. Example 4 shows that the process of this application can still be implemented with a lower Bi2O3 addition amount, and Example 5 shows that the process of this application can still be implemented with a higher Bi2O3 addition amount. Comparisons 1 and 4 with Example 1 respectively verify that the performance of samples using only the second sintering aid component and samples using only the first sintering aid component is inferior to that of samples using the composite sintering aid, and the influence of the total amount of sintering aid added on the results is eliminated, verifying the superiority of the composite sintering aid over a single sintering aid. Comparison 2 with Example 1 verifies that pre-sintering treatment has a beneficial effect on sample performance. Comparison 3 with Example 1 verifies that the "no annealing required" process route of this application is more advantageous than the conventional annealing post-treatment route.

[0136] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing lead zirconate titanate-based piezoelectric ceramics, characterized in that, include: Doped and modified lead zirconate titanate-based ceramic powder is mixed with a composite sintering aid and pre-sintered to obtain pre-sintered powder. The composite sintering aid includes a first sintering aid component and a second sintering aid component. The first sintering aid component includes one or more of Bi2O3, CuO, ZnO, and PbO, and the second sintering aid component includes one or more of Li2CO3, B2O3, V2O5, and SiO2. The pre-sintered powder is subjected to hot pressing sintering under an inactive atmosphere to obtain a sintered body. The sintered body is subjected to an upper electrode treatment, an electrode sintering treatment, and a polarization treatment in sequence to obtain the lead zirconate titanate-based piezoelectric ceramic.

2. The method according to claim 1, characterized in that, The doped lead zirconate titanate-based ceramic powder includes one or more of the following types: donor doping, acceptor doping, equivalent substitution, and composite doping.

3. The method according to claim 1, characterized in that, The doping elements of the doped lead zirconate titanate-based ceramic powder include one or more of Mn, Fe, Sb, Nb, La, W, Ba, Sr, Ca, Zr, and Sn, wherein the mass fraction of the doping elements in the doped lead zirconate titanate-based ceramic powder is 0.1%-1%.

4. The method according to claim 3, characterized in that, The method for providing the doped and modified lead zirconate titanate-based ceramic powder includes: The raw material powder is mixed with the modifying component and subjected to high-temperature calcination to obtain the doped modified lead zirconate titanate-based ceramic powder, wherein the raw material powder includes PbO, TiO2 and ZrO2, and the modifying component includes the doping element; The high-temperature calcination treatment includes a first heat preservation treatment and a second heat preservation treatment performed sequentially. The temperature of the first heat preservation treatment is 500℃-700℃ and the time of the first heat preservation treatment is 1h-4h. The temperature of the second heat preservation treatment is 750℃-950℃ and the time of the second heat preservation treatment is 2h-8h.

5. The method according to any one of claims 1-4, characterized in that, Based on the total mass of the doped and modified lead zirconate titanate-based ceramic powder, the composite sintering aid includes 0.05%-1.5% of the first sintering aid component and 0.05%-1.5% of the second sintering aid component.

6. The method according to claim 1, characterized in that, The temperature of the pre-sintering treatment is 500℃-1000℃, and the holding time of the pre-sintering treatment is 1h-10h.

7. The method according to claim 1 or 6, characterized in that, Also includes: After the pre-sintering treatment, a cooling treatment is performed. The cooling treatment has a cutoff temperature of 500℃-700℃ and a cooling rate of no more than 10℃ / min.

8. The method according to claim 1, characterized in that, The hot pressing sintering treatment is performed at a temperature of 800℃-1000℃ for 10 min-120 min, and / or at a pressure of 10 MPa-60 MPa.

9. A lead zirconate titanate-based piezoelectric ceramic prepared by the method according to any one of claims 1-8.

10. The application of lead zirconate titanate-based piezoelectric ceramics prepared by the method according to any one of claims 1-8 in piezoelectric actuators, ultrasonic transducers, piezoelectric sensors, piezoelectric actuators, and electronic ceramic devices.

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