A plzst-based antiferroelectric ceramic material, a preparation method and application thereof

Abstract

This invention belongs to the field of electronic ceramic materials technology, specifically relating to a PLZST-based antiferroelectric ceramic material, its preparation method, and its application. The chemical formula of the material is: (Pb 1‑3x / 2 La x (Zr) 1‑y‑ 0.05 Sn y Ti 0.05 ) 1‑m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2; where: 0.01≤ x ≤0.10; 0.10≤ y ≤0.30; 0.001≤ m ≤0.010; 0.1≤ n ≤0.5. Compared with existing technologies, this invention solves the problem that existing technologies cannot simultaneously achieve antiferroelectric energy storage characteristics, breakdown field strength, mechanical strength, and energy storage efficiency. This solution synergistically achieves grain refinement, grain boundary strengthening, and defect suppression.

Description

Technical Field

[0001] This invention belongs to the field of electronic ceramic materials technology, specifically relating to a PLZST-based antiferroelectric ceramic material, its preparation method, and its application. Background Technology

[0002] Lead lanthanum zirconate titanate (Pb,La)(Zr,Sn,Ti)O3 (PLZST)-based antiferroelectric ceramics possess unique field-induced antiferroelectric-ferroelectric phase transition characteristics, exhibiting high releaseable energy density during energy storage and large electrostriction output during actuation. This makes them a key candidate material for manufacturing next-generation high-performance pulsed power capacitors, large-displacement actuators, and other electronic components. However, the large-scale application of this material system has long been limited by reliability issues caused by its microstructural defects: to achieve high density, traditional PLZST ceramics require high-temperature sintering, a process that easily induces abnormal grain growth. Large grains not only reduce the number of grain boundaries per unit volume—grain boundaries are effective barriers hindering charge transport and increasing breakdown field strength—thus limiting its maximum operating electric field and energy storage density; more seriously, the coarse-grained structure directly leads to low intrinsic hardness and poor fracture toughness, making ceramic components highly susceptible to microcracks and even brittle fracture under subsequent processing, assembly, and high-field cyclic operation conditions, severely threatening the long-term service life and reliability of the devices.

[0003] To improve the above performance, existing technologies mainly attempt to improve it in the following three directions: (1) Optimization of raw materials and processes, such as using nanoparticles or hot pressing / hot isostatic pressing sintering. However, nanoparticles are expensive and prone to agglomeration, and hot pressing is a complex and inefficient process, making it difficult to apply to the large-scale production of devices with complex shapes. (2) Single ion doping, such as introducing Y 3+ W 6+Plasma. Although such methods can refine grains or adjust electrical properties to a certain extent, they often have trade-offs. For example, single donor doping can introduce a large number of oxygen vacancies while refining grains, which can deteriorate insulation performance; while partial doping can even destroy the stability of the antiferroelectric phase or have a negative impact on density. (3) Introducing low-melting-point sintering aids, such as Bi2O3, B2O3 or SiO2-based glass phases. The main purpose of these additives is to reduce the sintering temperature to adapt to the co-firing process of multilayer devices, but the continuous insulating phase or impurity phase formed at the grain boundaries usually significantly degrades the dielectric constant and energy storage characteristics of the material and damages the high-temperature stability. Some patents in recent years have also reflected the above-mentioned technical limitations. For example, patent CN112960981B discloses a method to reduce the sintering temperature of PLZST ceramics by introducing Al-Na-SiO2 glass phase. Although it improves density and breakdown field strength, the introduction of glass phase inevitably brings impurity phases, which pose a potential threat to the temperature stability of antiferroelectric properties. Patent CN116813337A improves the sintering behavior of ceramics in a reducing atmosphere by adding Y2(CO3)3, achieving grain refinement and high breakdown field strength. However, its technical approach mainly addresses the process compatibility issues of co-firing with base metal electrodes, with the core objective of enhancing electrical properties (breakdown field strength), without explicitly considering or designing for the synergistic enhancement of mechanical properties (such as hardness and fracture toughness) in material design. Furthermore, patent CN115894019A lowers the sintering temperature of PLZST antiferroelectric ceramic materials by adding sintering aids such as nano-copper oxide and lead borosilicate glass; patent CN118290146A lowers the sintering temperature of the matrix by adding nano-ZnO as a sintering aid. Similarly, the introduction of the glass phase inevitably introduces impurities, posing a potential threat to the temperature stability of the antiferroelectric properties.

[0004] Therefore, how to maintain the excellent antiferroelectric energy storage characteristics of PLZST ceramics while simultaneously improving its breakdown field strength, mechanical strength and energy storage efficiency remains a key challenge for this material system in high-power and high-reliability applications. Summary of the Invention

[0005] The purpose of this invention is to provide a PLZST-based antiferroelectric ceramic material, its preparation method, and its applications to solve at least one of the aforementioned problems, thereby addressing the issue that existing technologies cannot simultaneously achieve antiferroelectric energy storage characteristics, breakdown field strength, mechanical strength, and energy storage efficiency. This solution synergistically achieves grain refinement, grain boundary strengthening, and defect suppression.

[0006] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a PLZST-based antiferroelectric ceramic material, the chemical formula of which is: (Pb 1-3x / 2 La x(Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2; In the formula: 0.01 ≤ x ≤ 0.10; 0.10 ≤ y ≤ 0.30; 0.001 ≤ m ≤ 0.010; 0.1 ≤ n ≤0.5.

[0007] Preferably, the material is: The average grain size is 0.7~1.5 μm; The Vickers hardness is not less than 700 HV0.5.

[0008] The second aspect of this invention discloses a method for preparing the PLZST-based antiferroelectric ceramic material as described above, comprising the following steps: (1) Based on the chemical formula (Pb) 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt The stoichiometric ratio of Pb source, La source, Zr source, Sn source, Ti source, Y source, Nb source and SiO2 is weighed out. (2) Mix the raw materials weighed in step (1) and ball mill them. After drying, sieve them to obtain a uniformly mixed powder. (3) The powder obtained in step (2) is pre-calcined to synthesize the PLZST main crystalline phase to obtain pre-calcined powder; (4) The pre-calcined powder obtained in step (3) is ball-milled a second time, dried, and then sieved a second time to obtain intermediate powder; (5) Add a binder to the intermediate powder obtained in step (4) and granulate it, then dry press it to form a ceramic green body; (6) The ceramic green body obtained in step (5) is heated to remove the binder, and then sintered to obtain a dense ceramic body; (7) The dense ceramic blank obtained in step (6) is ground and polished on both sides, then coated with conductive paste and sintered for a second time to form an electrode, thus obtaining PLZST-based antiferroelectric ceramic material.

[0009] Preferably, step (1) includes: The Pb source is an oxide of Pb; The La source is an oxide of La; The Zr source is an oxide of Zr; The Sn source is an oxide of Sn; The Ti source is an oxide of Ti; The Y source is an oxide of Y; The Nb source is an oxide of Nb.

[0010] Preferably, step (2) includes: The ball milling process takes 6 to 12 hours. The drying conditions are: drying at 120℃ for 3-5 hours; The sieve mesh size is 60-100 mesh.

[0011] Preferably, step (3) includes: The pre-calcination synthesis conditions are as follows: pre-calcination synthesis at 800~900℃ for 2~4 hours.

[0012] Preferably, step (4) includes: The secondary ball milling time is 8-12 hours; The mesh size of the secondary sieving is 60~100 mesh.

[0013] Preferably, step (6) includes: The conditions for heating and debinding are: debinding at 500~700℃ for 12~24 hours; The sintering conditions are: sintering at 1200~1280℃ for 2~4 hours.

[0014] Preferably, step (7) includes: The conductive paste is silver paste; The conditions for the secondary sintering are: sintering at 550°C for 30 minutes.

[0015] The third aspect of this invention discloses the application of the PLZST-based antiferroelectric ceramic material described above in the fabrication of antiferroelectric ceramic components.

[0016] The working principle of this invention is as follows: This invention uses PLZST as a matrix and simultaneously introduces a second component, Pb(Nb), into it. 0.5 Y 0.5PYN (short for O3) and trace amounts of SiO2 grain boundary strengthener are used to refine the grains through intragranular chemical pinning and strengthen the second phase of the grain boundary through the second component. The grain boundary is strengthened through the liquid phase sintering of SiO2 and the grain boundary pinning effect, thus synergistically achieving grain refinement, grain boundary strengthening and defect suppression.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1) Intragranular solute pinning achieves efficient grain refinement: This scheme introduces PYN to form (Nb) 0.5 Y 0.5 ) 4+ The composite ions generate significant differences in ionic radius at the B site, thereby inducing strong local lattice distortion and stress field. In the later stage of sintering, this stress field can pin the grain boundaries and inhibit grain boundary migration through the solute dragging effect, thereby refining the average grain size from 3~5 μm to about 1 μm, laying the structural foundation for improving the material's hardness and fracture toughness.

[0018] 2) Self-compensation of charge at B sites suppresses harmful defects: (Nb 0.5 Y 0.5 In complex ions, high-valence Nb 5+ (The benefactor) and low-priced Y 3 + The average price of (acceptor) is +4, similar to Zr. 4+ / Ti 4+ The matching of valence states forms a unique self-compensation mechanism for B-site charge. This mechanism can effectively suppress excessive oxygen vacancies caused by single doping, significantly reduce leakage current, and improve volume resistivity and dielectric strength, thereby ensuring the intrinsic high breakdown field strength.

[0019] 3) Grain boundary liquid phase strengthening simultaneously improves density and bonding strength: The introduction of trace amounts of SiO2 is the second key regulatory aspect of this scheme. Specifically, during the high-temperature sintering stage, SiO2 reacts with the matrix components to form a eutectic liquid phase. This liquid phase promotes particle rearrangement and pore expulsion through capillary action at high temperatures, bringing the ceramic density close to the theoretical limit. Furthermore, during the cooling process, the liquid phase is not completely dissolved but exists in the form of amorphous thin layers or nano-precipitates at grain boundaries, which can effectively pin the grain boundaries and significantly improve the grain boundary bonding strength.

[0020] 4) This scheme effectively improves the electrical and mechanical properties of antiferroelectric ceramics through a triple synergistic mechanism of intragranular pinning, grain boundary strengthening and defect suppression: The ceramic material prepared by this scheme can maintain excellent antiferroelectric energy storage characteristics (high energy storage density and efficiency) while also having high hardness, high breakdown field strength and high reliability.

[0021] 5) Simple process, suitable for industrialization: This invention can directly adopt the conventional solid-state reaction sintering method without special equipment (such as hot press furnace) or expensive raw materials (such as nano powder). It has a wide process window, good repeatability and low production cost, making it very suitable for the large-scale production of high-performance antiferroelectric ceramic components. Attached Figure Description

[0022] Figure 1 SEM images of the PLZST antiferroelectric ceramic materials prepared for Comparative Example 1(a), Comparative Example 2(b), and Example 1(c).

[0023] Figure 2 Hysteresis loop diagram of the PLZST antiferroelectric ceramic material prepared in Example 1. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments to enable those skilled in the art to more fully understand the invention. It should be understood that the drawings and specific embodiments are for illustrative purposes only and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials, processes, and structural features used in the present invention are all conventional techniques in the art.

[0025] This invention addresses the technical bottlenecks in existing PLZST-based antiferroelectric ceramics, such as the tendency for abnormal grain growth and the difficulty in synergistically improving mechanical and electrical properties. It also addresses the problem that existing modification techniques often focus on a single property and fail to achieve a balance between fine grain structure, high strength, and excellent antiferroelectric characteristics. The invention provides a PLZST-based antiferroelectric ceramic material with fine grains, high strength, and high energy storage performance, as well as its preparation method.

[0026] In a first aspect, the present invention provides a fine-grained, high-strength antiferroelectric ceramic material.

[0027] A fine-grained, high-strength antiferroelectric ceramic material, its chemical composition being predominantly (Pb). 1-3x / 2 La x (Zr) 1-y- 0.05 Sn y Ti 0.05 Using PbO3 (PLZST) as the matrix, the microstructure of the material is reconstructed by synergistically introducing two modifiers: the second component PYN and a trace amount of grain boundary strengthener SiO2, thereby achieving optimization of the microstructure and synergistic improvement of performance; the chemical formula of this antiferroelectric ceramic material is then expressed as: (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 )1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2.

[0028] Wherein, the mole fraction of La x Satisfies: 0.01 ≤ x ≤ 0.10, more preferably 0.02 ≤ x ≤0.08; mole fraction of Sn y Satisfies: 0.10 ≤ y ≤ 0.30; (Nb 0.5 Y 0.5 The amount of substitution of the complex ion at the B site m Satisfies: 0.001 ≤ m ≤ 0.010; Trace additive SiO2: introduced externally, with an addition amount of 0.1~0.5% of the total mass of the ceramic material powder. wt %, that is, 0.1 ≤ n ≤ 0.5.

[0029] Preferably, the antiferroelectric ceramics prepared by the above-mentioned component design have an average grain size that can be refined to about 1 μm (0.7~1.5 μm), a Vickers hardness of not less than 700 HV0.5 and reaching more than 900 HV0.5, a breakdown field strength of not less than 200 kV / cm and reaching nearly 280 kV / cm, and a storage density greater than 3 J / cm³. 3 And it can reach 6.5 J / cm 3 The energy storage efficiency is no less than 60% and can reach 84%.

[0030] The antiferroelectric ceramic material of the present invention utilizes Nb 5+ With Y 3+ The ionic radius mismatch generates a strong local stress field in the crystal lattice, which pins the grain boundaries through the solute dragging effect, refining the average grain size to about 1.0 μm; at the same time, it forms B-site charge self-compensation pairs, reduces the oxygen vacancy concentration, and improves resistivity and dielectric strength; the added SiO2 forms a liquid phase during sintering, which synergistically promotes densification and forms a second phase at the grain boundaries, strengthening the grain boundary bonding strength.

[0031] Secondly, the present invention provides a method for preparing the above-mentioned fine-grained, high-strength antiferroelectric ceramic material.

[0032] The method employs a solid-state synthesis approach and includes the following steps: S1. Using high-purity Pb3O4, La2O3, ZrO2, SnO2, TiO2, Y2O3, Nb2O5, and SiO2 with a purity of not less than 99.99% as raw materials, according to the target chemical formula (Pb1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2 is accurately weighed, and the weighed raw material is placed together with anhydrous ethanol and zirconium oxide ball milling media into a ball mill jar. The mixture is ball milled for 6 to 12 hours to make the raw material initially mixed evenly and refined. Then it is dried at 120℃ for 3 to 5 hours and passed through a 60 to 100 mesh sieve to obtain a uniformly mixed powder. S2. Pre-calcination synthesis: The powder of S1 is mixed evenly and pre-calcined at 800~900℃ for 2~4 hours to synthesize the PLZST main crystalline phase; S3. Secondary ball milling and molding: The powder after S2 pre-fired is ball milled again for 8-12 hours, dried, passed through a 60-100 mesh sieve, and granulated with 5-10% of the powder mass of binder. Then, it is dry-pressed to obtain ceramic green body. S4. Debinding and sintering: The green body obtained in S3 is debinded in a muffle furnace according to the set heating and holding program (maximum temperature 500~700℃, the heating program can be determined according to the specific process). Then, it is sintered in air at 1200~1280℃ for 2~4 hours and cooled with the furnace to obtain a dense ceramic body. S5. Processing: The dense ceramic blank sintered in S4 is ground and polished on both sides to a thickness of 0.3 mm. Then, silver paste is coated on both sides and sintered at 550℃ for 30 minutes to form electrodes, thus obtaining antiferroelectric ceramic material.

[0033] This antiferroelectric ceramic material can be used in the fabrication of pulsed power capacitors or large-displacement electro-strain actuators.

[0034] Example 1 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which x The value range is 0.02 to 0.08. y The value range is 0.10~0.30. mThe value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0035] The specific steps are as follows.

[0036] 1) Preparation of PLZST-based ceramic powder: Accurately weigh and analyze pure raw materials Pb3O4, La2O3, ZrO2, SnO2, TiO2, Y2O3, Nb2O5, and SiO2 according to the formula (where the chemical formula is as follows). x Take 0.04, y Take 0.3, m Take 0.4 mol%. n Take 0.3). Place all raw materials in a nylon ball mill jar, use zirconia balls as the grinding medium and anhydrous ethanol as the dispersant, and ball mill for 6 hours to ensure uniform mixing. Then dry and sieve.

[0037] 2) Ceramic forming and sintering: a. Synthetic powder: The sieved powder is placed in an alumina crucible and calcined at 850°C for 3 hours in an air atmosphere. Then, it is ball-milled for 12 hours under the same conditions. After drying, it is passed through a 100-mesh sieve to obtain a piezoelectric powder with good flowability.

[0038] b. Granulation and molding: An 8% (w / w) polyvinyl butyral (PVB) ethanol solution was added to the powder as a binder for granulation. The granulated powder was then dry-pressed under a pressure of 100 MPa to obtain a ceramic green body with a diameter of 15 mm and a thickness of approximately 1 mm.

[0039] c. Debinding and sintering: The green body is placed in a muffle furnace and slowly heated to 600°C according to the set program to completely remove the organic matter of the binder; the debinded green body is placed in a sealed alumina crucible and heated to 1250°C at 3°C / min in an air atmosphere, held for 3 hours, and then cooled naturally in the furnace to obtain a dense PLZST-based antiferroelectric ceramic sintered body.

[0040] 3) Processing and Electrode Preparation: The sintered body was ground and polished on both sides to a thickness of approximately 0.3 mm. Electrode slurry was coated on both sides of the polished ceramic sheet, and sintered at 550℃ for 30 minutes to form a good electrode surface for performance testing.

[0041] Example 2 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m(Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which x The value range is 0.02 to 0.08. y The value range is 0.10~0.30. m The value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0042] The difference between the preparation method in this embodiment and that in Example 1 is that... m Take 0.4 mol%. n Take 0.1. The remaining steps are the same as in Example 1.

[0043] Example 3 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which x The value range is 0.02 to 0.08. y The value range is 0.10~0.30. m The value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0044] The difference between the preparation method in this embodiment and that in Example 1 is that... m Take 0.4 mol%. n Take 0.5. The remaining steps are the same as in Example 1.

[0045] Example 4 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which xThe value range is 0.02 to 0.08. y The value range is 0.10~0.30. m The value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0046] The difference between the preparation method in this embodiment and that in Example 1 is that... m Take 0.1 mol%. n Take the optimal value of 0.3 from Examples 1-3. The remaining steps are the same as in Example 1.

[0047] Example 5 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which x The value range is 0.02 to 0.08. y The value range is 0.10~0.30. m The value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0048] The difference between the preparation method in this embodiment and that in Example 1 is that... m Take 0.7 mol%. n Take the optimal value of 0.3 from Examples 1-3. The remaining steps are the same as in Example 1.

[0049] Example 6 This embodiment provides a fine-grained, high-strength PLZST-based antiferroelectric ceramic material and its preparation method, the chemical formula of which is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2, of which x The value range is 0.02 to 0.08. y The value range is 0.10~0.30. mThe value range is 0.1~1.0 mol%. n The value range is 0.1 to 0.5.

[0050] The difference between the preparation method in this embodiment and that in Example 1 is that... m Take 1.0 mol%. n Take the optimal value of 0.3 from Examples 1-3. The remaining steps are the same as in Example 1.

[0051] Comparative Example 1 Using PLZST antiferroelectric ceramic material as a comparative example, its chemical formula is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 O3, of which x The value range is 0.02 to 0.08. y The value range is 0.10 to 0.30.

[0052] The preparation method of this comparative example differs from that of Example 1 in that the amount of Nb and Y added is 0g, and the amount of SiO2 used is 0g. The remaining steps are the same as in Example 1 (i.e., x Take 0.04, y Take 0.3, m Take 0 mol%. n Take 0).

[0053] Comparative Example 2 Using PLZST-based antiferroelectric ceramics without SiO2 as a comparative example, its chemical formula is (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3, in which x Taking the optimal value of 0.04 from Comparative Example 1, y Taking the optimal value of 0.3 from Comparative Example 1, m Take 0.5 mol%, the amount of SiO2 used is 0 g ( n Take 0). The remaining steps are the same as in Example 1.

[0054] Performance characterization and results analysis 1) The material performance testing methods are as follows: Average grain size: After polishing and hot etching the cross-section of the ceramic sample, the size of at least 10 grains was observed using a scanning electron microscope (SEM) and the average value was calculated.

[0055] Vickers hardness: A Vickers hardness tester was used, with a test load of HV0.5 (4.9N) and a holding time of 15s. Five points were tested for each sample and the average value was taken.

[0056] Electrical properties: The hysteresis loop of the sample was measured using a ferroelectric analyzer.

[0057] The ceramic samples prepared in Examples 1-6 and Comparative Examples 1-2 were characterized as follows.

[0058] Table 1 Summary of performance test results for Examples 1-6 and Comparative Examples 1-2 By comparing the performance in Table 1, and combining it with the appendix... Figures 1-2 The following conclusions can be drawn, which fully confirm the beneficial effects of the present invention: Microstructure Evolution and Mechanical Property Enhancement: Microstructure Analysis (with appendix) Figure 1 The results of the tests and performance tests (Table 1) together indicate that the strengthening path of the material follows a dual mechanism of "grain refinement" and "grain boundary strengthening". Comparative Example 2 (doped with PYN only) achieved grain refinement (~1.0 μm), but the increase in hardness (655 HV0.5) was limited, indicating that single grain refinement has a bottleneck. In contrast, Example 1 (PYN+SiO2), under the same fine grain structure, exhibited significant "transgranular fracture" characteristics on the fracture surface. Figure 1 c) This is direct evidence that the grain boundary bonding strength exceeds the intrinsic strength of the grains. This toughened grain boundary originates from the grain boundary phase formed by SiO2, which enables the material to achieve a Vickers hardness of 908 HV0.5, realizing a qualitative change in mechanical properties.

[0059] Synergistic optimization of electrical performance: Electrical performance (with appendix) Figure 2 Table 1 shows that Example 1 achieved the best overall energy storage characteristics: 6.5 J / cm at a high breakdown field strength of 264 kV / cm. 3 High releasable energy storage density (W rec It has a high energy storage efficiency of 84% and a high energy storage efficiency (η). Compared with Comparative Example 1 (unmodified), its breakdown field strength, W rec The efficiency and efficiency of η were increased by 30.7%, 44.4%, and 13 percentage points, respectively. Compared with Comparative Example 2 (PYN only), all electrical properties were comprehensively improved under the premise of the same grain size. This proves that the introduction of SiO2 not only strengthens the grain boundaries, but also optimizes the interfacial charge distribution and electric field uniformity, thus producing a significant synergistic effect of 1+1>2 with PYN. While improving the withstand voltage, it also optimizes the squareness and energy storage characteristics of the antiferroelectric double loop.

[0060] In summary, this invention introduces Pb(Nb) 0.5 Y 0.5By controlling the content of O3 and trace amounts of SiO2 within an optimal range, the synergistic effect of "intragranular solute pinning and refinement" and "grain boundary liquid phase strengthening" was successfully achieved, resulting in a grain size of approximately 1.0 μm, a Vickers hardness >900 HV0.5, a breakdown field strength >250 kV / cm, and a releaseable energy density >6.0 J / cm³. 3 Furthermore, the high-performance antiferroelectric ceramic with an energy storage efficiency >80%, namely Example 1, represents the optimal implementation scheme of the present invention. In addition, the preparation method of the present invention is entirely based on mature solid-state reaction and sintering processes, with a wide process window, easy parameter control, compatibility with traditional processes, good repeatability, and broad prospects for industrial application.

[0061] This invention resolves the contradiction between the electrical and mechanical properties of antiferroelectric ceramics through a synergistic mechanism of intragranular pinning, grain boundary strengthening, and defect suppression. The resulting ceramic material exhibits high density, excellent hardness, breakdown field strength, and antiferroelectric energy storage characteristics. Furthermore, the fabrication process is simple and low-cost, making it suitable for large-scale applications in high-performance pulsed power capacitors and electrostrictive strain devices.

[0062] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A PLZST-based antiferroelectric ceramic material, characterized in that, The chemical formula of the material is: (Pb 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt %SiO2; In the formula: 0.01 ≤ x ≤ 0.10；0.10 ≤ y ≤ 0.30；0.001 ≤ m ≤ 0.010；0.1 ≤ n ≤ 0.5。 2. The PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that, The materials mentioned: The average grain size is 0.7~1.5 μm; The Vickers hardness is not less than 700 HV0.

5.

3. A method for preparing a PLZST-based antiferroelectric ceramic material as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Based on the chemical formula (Pb) 1-3x / 2 La x (Zr) 1-y-0.05 Sn y Ti 0.05 ) 1-m (Nb 0.5 Y 0.5 ) m O3+ n wt The stoichiometric ratio of Pb source, La source, Zr source, Sn source, Ti source, Y source, Nb source and SiO2 is weighed out. (2) Mix the raw materials weighed in step (1) and ball mill them. After drying, sieve them to obtain a uniformly mixed powder. (3) The powder obtained in step (2) is pre-calcined to synthesize the PLZST main crystalline phase to obtain pre-calcined powder; (4) The pre-calcined powder obtained in step (3) is ball-milled a second time, dried, and then sieved a second time to obtain intermediate powder; (5) Add a binder to the intermediate powder obtained in step (4) and granulate it, then dry press it to form a ceramic green body; (6) The ceramic green body obtained in step (5) is heated to remove the binder, and then sintered to obtain a dense ceramic body; (7) The dense ceramic blank obtained in step (6) is ground and polished on both sides, then coated with conductive paste and sintered for a second time to form an electrode, thus obtaining PLZST-based antiferroelectric ceramic material.

4. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (1) includes: The Pb source is an oxide of Pb; The La source is an oxide of La; The Zr source is an oxide of Zr; The Sn source is an oxide of Sn; The Ti source is an oxide of Ti; The Y source is an oxide of Y; The Nb source is an oxide of Nb.

5. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (2) includes: The ball milling process takes 6 to 12 hours. The drying conditions are: drying at 120℃ for 3-5 hours; The sieve mesh size is 60-100 mesh.

6. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (3) includes: The pre-calcination synthesis conditions are as follows: pre-calcination synthesis at 800~900℃ for 2~4 hours.

7. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (4) includes: The secondary ball milling time is 8-12 hours; The mesh size of the secondary sieving is 60~100 mesh.

8. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (6) includes: The conditions for heating and debinding are: debinding at 500~700℃ for 12~24 hours; The sintering conditions are: sintering at 1200~1280℃ for 2~4 hours.

9. The method for preparing a PLZST-based antiferroelectric ceramic material according to claim 3, characterized in that, Step (7) includes: The conductive paste is silver paste; The conditions for the secondary sintering are: sintering at 550°C for 30 minutes.

10. The application of the PLZST-based antiferroelectric ceramic material as described in claim 1 or 2 in the fabrication of antiferroelectric ceramic components.

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