Potassium tantalate niobate ceramic and preparation method thereof

Abstract

The invention belongs to the field of ceramic materials, and particularly relates to potassium tantalate niobate ceramic and a preparation method thereof. The potassium tantalate niobate ceramic comprises the following components in parts by mass: a chemical formula of K1 + Z-YRuYTa (1-x) NbxO3, wherein X is greater than or equal to 0.38 and less than or equal to 0.42, Z is greater than or equal to 0.10 and less than or equal to 0.20, and Y is greater than or equal to 0.35 and less than or equal to 0.50. According to the ceramic and the preparation method thereof, the Ru element is introduced as a doping ion for the first time, comprehensive improvement of the potassium tantalate niobate ceramic in the aspects of insulativity, stability, manufacturability and environmental protection is achieved through the systematic design of element doping innovation, component parameter optimization and technological method cooperation, and remarkable technical progress and industrial application potential are achieved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials, and particularly relates to a potassium tantalate niobate ceramic and its preparation method. Background Technology

[0002] To address the strategic need for green and sustainable development in the global electronics and information industry, developing high-performance lead-free ferroelectric materials that can replace traditional lead-based materials has become a core technological problem that urgently needs to be solved in this field. Although lead-based materials (such as lead zirconate titanate, PZT) possess excellent electrical properties, the lead pollution generated during their preparation, processing, and disposal causes serious harm to the ecological environment and human health, making it difficult to meet increasingly stringent environmental regulations.

[0003] Potassium tantalate (KTa) 1-x Nb x O3 (KTN) ceramics, due to their tunable Curie temperature, high dielectric constant, and good pyroelectric properties, have shown broad application prospects and are considered a promising environmentally friendly alternative material. However, KTN ceramics prepared by existing technologies still have two prominent technical defects: First, their insulation performance is poor, manifested as a large leakage current density under high electric fields, leading to high device energy consumption, severe heat generation, and susceptibility to breakdown failure; second, their resistance to electrical fatigue is poor, with significant attenuation of polarization intensity under cyclic electric fields, which restricts their reliability and service life under long-term dynamic operating conditions.

[0004] The root cause of the aforementioned technical bottlenecks lies in the microstructural defects of KTN ceramics, particularly the problems that easily occur during conventional sintering, such as potassium volatilization, oxygen vacancy formation, and poor control of grain boundary characteristics. Therefore, from the perspective of material preparation processes, significantly improving the density, insulation, and structural stability of KTN ceramics through component design, sintering process optimization, and microstructural control is of crucial industrial significance for overcoming its performance bottlenecks and promoting the practical application of this lead-free material in high-end electronic devices. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, a method for preparing potassium tantalate niobate ceramics with simple preparation and superior ferroelectric properties is proposed.

[0006] The technical solution of the present invention is as follows: On one hand, the present invention provides a potassium tantalate niobate ceramic with the chemical formula K. 1+Z-Y Ru Y Ta 1-x Nb x O3, wherein the amount of Nb is 0.38≤X≤0.42, 0.10≤Z≤0.20, and 0.35≤Y≤0.50.

[0007] The chemical formula parameters of this invention have been systematically optimized. Specifically, X (Nb content): 0.38 ≤ X ≤ 0.42, controlling the ferroelectric-paraelectric phase transition temperature to ensure the Curie point adapts to the device's operating temperature range; Z (K excess coefficient): 0.10 ≤ Z ≤ 0.20, compensating for potassium volatilization and maintaining structural stability; Y (Ru doping amount): 0.35 ≤ Y ≤ 0.50, optimizing the doping concentration to balance insulation and ferroelectricity. Therefore, this invention ensures that the material possesses tunable ferroelectric properties and a stable crystal structure, balancing insulation, ferroelectricity, and process feasibility.

[0008] Preferably, when the amount of Nb is 0.38≤x<0.40, Z is 0.10≤Z<0.15, and the doping concentration ratio X / Z is 2.5-4; When the amount of Nb is 0.40≤X≤0.42 and Z is 0.15≤Z≤0.2, the doping concentration ratio X / Z is 2-2.8. This scheme further refines the matching relationship between different Nb content ranges and Z values. By controlling the X / Z ratio, the lattice distortion and phase transition behavior are optimized, enabling the ceramic to maintain excellent electrical properties in different application scenarios.

[0009] On the other hand, the present invention provides a method for preparing the above-mentioned potassium tantalate niobate ceramic, using high-purity K2CO3, Ru2CO3, Nb2O5, and Ta2O5 as raw materials, according to K 1+Z-Y Ru Y Ta 1-x Nb x The stoichiometric ratio of O3 is used to select the raw materials for the required ceramic components: K2CO3, Ru2CO3, Nb2O5, and Ta2O5.

[0010] Specifically, the steps include the following: S1. Preparation of abrasive A: The raw materials for the required ceramic components are selected according to the stoichiometric ratio. The raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconia balls are mixed in the specified ratio and ball-milled for 8 hours to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconia balls is (1-1.5):1.5:2.5. The raw material A was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 700°C for 6 hours to obtain polycrystalline material A. Take out polycrystalline material A and perform wet grinding using an agate mortar and pestle, with anhydrous ethanol as the dispersion medium, and continue grinding for 60 minutes to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:1.

[0011] This invention employs wet ball milling with anhydrous ethanol as the dispersion medium, effectively preventing the agglomeration of Nb₂O₅ and Ta₂O₅ particles due to van der Waals forces and ensuring uniform mixing at the nanoscale. In terms of proportion design, an appropriate amount of ethanol provides a good dispersion environment while avoiding excessive liquid leading to excessively high slurry viscosity; a higher proportion of zirconia balls provides sufficient collision and shear forces, suitable for the effective grinding of the high-hardness oxide Ta₂O₅, and the high specific surface area significantly enhances the activity of subsequent solid-phase reactions. Simultaneously, the uniformly mixed Nb₂O₅ and Ta₂O₅ obtained in this process are more likely to form a uniform Ta,Nb solid solution precursor during pre-calcination at 700℃, avoiding localized component segregation.

[0012] S2. Preparation of abrasive material B: The raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconium oxide balls were mixed in a certain proportion and ball-milled for 6 h to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was (1-1.5):1.5:2. The raw material B was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 750°C for 6 hours to obtain polycrystalline material B. Take out polycrystalline material B and perform wet grinding using an agate mortar and pestle, with anhydrous ethanol as the dispersion medium, and continue grinding for 120 minutes to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:1.

[0013] Both K₂CO₃ and Ru₂CO₃ are carbonates, which are hygroscopic and prone to agglomeration. Wet ball milling is performed in anhydrous ethanol to isolate moisture, prevent hydrolysis of the raw materials or formation of hydrates, and ensure accurate stoichiometry. A slightly lower ball-to-material ratio is used; carbonates have low hardness, and a ratio of 2 is sufficient for fine grinding, while also reducing impurities introduced by ball milling media wear. Ru₂CO₃ is present in small amounts but is crucial; wet ball milling ensures its uniform mixing with K₂CO₃ at the molecular level, preventing localized Ru enrichment and the formation of impurity phases during subsequent sintering. The carbonate mixture after wet ball milling has a large specific surface area, allowing for more thorough decomposition and solid-phase reaction during pre-calcination at 750°C, forming a uniform K–Ru–O precursor.

[0014] S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a high-temperature furnace for pre-firing. The heating rate is 80-100℃ / h, and the temperature is held at 700-720℃ for 4h to obtain sintered pre-synthetic material C.

[0015] S4. Grinding and sieving: The pre-synthetic material C obtained in step S3 is crushed and added to anhydrous ethanol as a dispersant. The mixture is then placed in a ball mill jar and ball-milled for 6 hours to obtain powder D. The mass ratio of the synthetic material C, anhydrous ethanol, and zirconium oxide balls is 2:1:3.

[0016] S5. Grinding and granulation: The powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then sieved through a 60-mesh sieve to granulate, so as to ensure that the powder particles are uniform; the mass fraction of the PVA colloid is 5%.

[0017] S6, Tableting and dispensing: The granules obtained from step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press. The sheets are then kept at 200℃ for 40 min to drain the water, and then kept at 650℃ for 60 min to remove the binder, thus obtaining the corresponding ceramic sample. The cylindrical sheets are then placed in a high-temperature furnace.

[0018] Preferably, when 0.35≤Y≤0.40, in step S6, the drainage process has a heating rate of 2-3℃ / min and the glue discharge rate has a heating rate of 5-6℃ / min; when 0.40<Y≤0.50, in step S6, the drainage process has a heating rate of 4-5℃ / min and the glue discharge rate has a heating rate of 7-8℃ / min.

[0019] For step S6, the drainage stage removes physically adsorbed water and bound water from the PVA colloid. During the debinding / decomposition stage, the PVA polymer chains undergo thermal decomposition, carbonization, and eventual oxidation to CO2 before being discharged. When 0.35 ≤ Y ≤ 0.40, the Ru doping amount in this range is moderate and can significantly improve performance, but the resulting crystal structure is more sensitive to internal stress. Excessive drainage can lead to a sudden increase in the vapor pressure inside the sample, easily causing microcracks. When 0.40 < Y ≤ 0.50 (high Ru doping), the high Ru doping content significantly strengthens the grain boundaries, giving the green blank higher mechanical strength and crack resistance during the debinding stage. The strengthened structure can withstand faster vapor release processes, improving production efficiency. On the other hand, Ru itself or its oxides (such as RuO2) are good oxidation catalysts. Under Ru catalysis, even with rapid heating, the decomposed carbon can be quickly and completely oxidized, avoiding premature grain growth caused by prolonged exposure to the medium temperature range.

[0020] S7, Sintering: The sample obtained after debinding in step S6 is sintered at a temperature of 1100-1200℃ for 2 hours.

[0021] Preferably, when 0.10≤Z<0.13, the heating rate of the sintering process in step S7 is 5-6℃ / min and the cooling rate is 7-9℃ / min; when 0.13≤Z≤0.2, the heating rate of the sintering process in step S7 is 4-4.8℃ / min and the cooling rate is 2-3℃ / min.

[0022] The Z value is used to compensate for potassium volatilization during high-temperature sintering. The Z value directly affects the stoichiometry, densification behavior, and grain growth of the final ceramic. Therefore, when 0.10 ≤ Z < 0.13, insufficient potassium compensation increases the risk of stoichiometric deviation due to potassium volatilization during sintering, necessitating a shorter high-temperature residence time. When 0.13 ≤ Z ≤ 0.20, sufficient potassium excess allows for slower sintering kinetic control, aiming for extreme densification and structural relaxation.

[0023] In summary, the preparation method of this invention employs stepwise pre-firing in steps S1 and S2 to treat the main material and dopants separately, avoiding premature reaction of Ru and Ta / Nb at high temperatures, improving component uniformity, reducing impurity introduction, and enhancing reaction activity. Step S3 involves low-temperature pre-synthesis, using a holding temperature of 700–720℃ for 4 hours to promote the initial completion of the solid-phase reaction and lower the final sintering temperature. Steps S4 and S5 involve wet grinding and granulation using ethanol as a medium to avoid moisture introduction, reducing the PVA colloid concentration to 5%, reducing organic residue, achieving uniform powder coating and optimized particle size distribution, and increasing the density of the green body. Step S6 involves stepwise debinding, combining debinding at 200℃ with debinding at 650℃ to prevent rapid PVA decomposition leading to cracking and improve yield. Step S7 involves a segmented sintering process, dynamically adjusting the heating / cooling rate according to Y and Z values ​​to achieve uniform grain growth, pore removal, and controllable microstructure growth, resulting in highly dense, low-defect ceramics. All steps are unified and coordinated.

[0024] The preparation method of this patent and its specific chemical formula constitute a highly synergistic and specially designed integrated system. X, Z, and Y in the chemical formula jointly determine the theoretical target ferroelectric properties of the material. This preparation method optimizes a series of interconnected process parameters (such as ball milling method and ratio, pre-firing temperature, debinding rate, sintering temperature and heating / cooling rate, etc.) to transform these chemical parameters into a controllable process, which is ultimately reflected in the microstructure.

[0025] The beneficial effects of this invention are as follows: The introduction of Ru as a dopant ion for the first time has several advantages. First, it provides a stable electronic configuration, forming a solid solution structure and reducing oxygen vacancies, thus significantly lowering leakage current. Second, the high Ru-O bond energy helps stabilize the crystal structure during high-temperature sintering and suppresses K+ ionization. + The volatilization of Ru ions helps maintain the stability of the stoichiometry and improves the insulation performance of ceramics. Furthermore, the segregation of Ru ions at grain boundaries can form a high-resistivity grain boundary layer, hindering carrier migration and further improving the ceramic's withstand voltage and resistance to electrical fatigue.

[0026] This invention, by determining the doping amount, selecting the optimal ratio, and using a dedicated preparation method, produces high-quality ceramics with good uniformity and significantly improved ceramic quality; the leakage current performance of the ceramics is also greatly improved, further promoting the application of KTN ceramic devices.

[0027] This preparation method is simple to operate and low in cost, greatly reducing production costs. Furthermore, this invention lowers the sintering temperature to 1100–1200℃, reducing energy consumption and aligning with green manufacturing trends; it suppresses component volatilization and abnormal grain growth, avoiding the volatilization of elements such as K and Ru at high temperatures, resulting in a uniform and fine microstructure; and it improves process controllability, making low-temperature processes easier to implement for large-scale industrial production. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The XRD pattern of the potassium tantalate niobate ceramic prepared in Example 1 of this invention; Figure 2 The XRD pattern of the potassium tantalate niobate ceramic prepared in Example 2 of this invention; Figure 3 The hysteresis loop diagram of the potassium tantalate niobate ceramic prepared in Example 3 of this invention; Figure 4 The leakage current diagram is shown for the potassium tantalate niobate ceramic prepared in Example 4 of this invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0031] Example 1 A potassium tantalate niobate ceramic K 1+Z-Y Ru Y Ta 1-x Nb x O3, where X=0.38, Z=0.10, Y=0.4.

[0032] The above-mentioned method for preparing potassium tantalate niobate ceramics, using high-purity K₂CO₃, Ru₂CO₃, Nb₂O₅, and Ta₂O₅ as raw materials, specifically includes the following steps: S1. Preparation of abrasive material A: The raw materials for the required ceramic components are selected according to the stoichiometric ratio. The raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconia balls are mixed in the specified ratio and ball-milled for 8 hours to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconia balls is 1:1.5:2.5. The raw material A was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 700°C for 6 hours to obtain polycrystalline material A. Take out polycrystalline material A and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 60 minutes to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:1. S2. Preparation of abrasive material B: The raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconium oxide balls were mixed in a certain proportion and ball-milled for 6 h to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was 1.2:1.5:2. The raw material B was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 750°C for 6 hours to obtain polycrystalline material B. Take out polycrystalline material B and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 120 minutes to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:1. S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a high-temperature furnace for pre-firing. The heating rate is 85℃ / h, and the temperature is held at 700℃ for 4h to obtain sintered pre-synthetic material C. S4. Grinding and sieving: The pre-synthetic material C obtained in step S3 is crushed and added to anhydrous ethanol as a dispersant. The mixture is then placed in a ball mill jar and ball-milled for 6 hours to obtain powder D. The mass ratio of the synthetic material C, anhydrous ethanol and zirconium oxide balls is 2:1:3. S5. Grinding and granulation: The powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then granulated by sieving through a 60-mesh sieve to ensure uniform powder particles; the mass fraction of the PVA colloid is 5%. S6, Tableting and dispensing: The granules obtained from granulation in step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press; the sheets are then drained by holding at 200℃ for 40 min, and then debinded by holding at 650℃ for 60 min to obtain the corresponding ceramic sample. The cylindrical sheets are then placed in a high-temperature furnace. The drainage process in this step is carried out at a heating rate of 2℃ / min, and the debinding process is carried out at a heating rate of 5℃ / min. S7, Sintering: The sample obtained after debinding in step S6 was sintered at 1100℃ for 2 hours. The heating rate during this sintering process was 5℃ / min, and the cooling rate was 7℃ / min. Figure 1 The figure shows the XRD pattern of the potassium tantalate niobate ceramic prepared in Example 1. It can be seen from the figure that the ceramic sheet is pure phase and free of impurities.

[0033] Example 2 A potassium tantalate niobate ceramic K 1+Z-Y Ru Y Ta 1-x Nb x O3, where X=0.39, Z=0.14, Y=0.4.

[0034] The above-mentioned method for preparing potassium tantalate niobate ceramics, using high-purity K₂CO₃, Ru₂CO₃, Nb₂O₅, and Ta₂O₅ as raw materials, specifically includes the following steps: S1. Preparation of abrasive material A: The raw materials for the required ceramic components are selected according to the stoichiometric ratio. The raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconia balls are mixed in the specified ratio and ball-milled for 8 hours to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconia balls is 1.5:1.5:2.5. The raw material A was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 700°C for 6 hours to obtain polycrystalline material A. Take out polycrystalline material A and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 60 minutes to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:1. S2. Preparation of abrasive material B: The raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconium oxide balls were mixed in a certain proportion and ball-milled for 6 h to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was 1:1.5:2. The raw material B was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 750°C for 6 hours to obtain polycrystalline material B. Take out polycrystalline material B and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 120 minutes to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:1. S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a high-temperature furnace for pre-firing. The heating rate is 100℃ / h, and the temperature is held at 710℃ for 4h to obtain sintered pre-synthetic material C. S4. Grinding and sieving: The pre-synthetic material C obtained in step S3 is crushed and added to anhydrous ethanol as a dispersant. The mixture is then placed in a ball mill jar and ball-milled for 6 hours to obtain powder D. The mass ratio of the synthetic material C, anhydrous ethanol and zirconium oxide balls is 2:1:3. S5. Grinding and granulation: The powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then granulated by sieving through a 60-mesh sieve to ensure uniform powder particles; the mass fraction of the PVA colloid is 5%. S6, Tableting and dispensing: The granules obtained from granulation in step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press; the sheets are then drained by holding at 200℃ for 40 min, and then debinded by holding at 650℃ for 60 min to obtain the corresponding ceramic sample. The cylindrical sheets are then placed in a high-temperature furnace; the drainage process in this step is carried out at a heating rate of 2℃ / min; the debinding process is carried out at a heating rate of 6℃ / min. S7, Sintering: The sample obtained after debinding in step S6 was sintered at a temperature of 1200℃ for 2 hours. The heating rate during the sintering process was 4.8℃ / min and the cooling rate was 2℃ / min. like Figure 2 The figure shows the XRD pattern of the potassium tantalate niobate ceramic prepared in Example 2. It can be seen from the figure that the ceramic sheet is pure phase and free of impurities.

[0035] Example 3 A potassium tantalate niobate ceramic K 1+Z-Y Ru Y Ta 1-x Nb x O3, where X=0.41, Z=0.17, Y=0.5.

[0036] The above-mentioned method for preparing potassium tantalate niobate ceramics, using high-purity K₂CO₃, Ru₂CO₃, Nb₂O₅, and Ta₂O₅ as raw materials, specifically includes the following steps: S1. Preparation of abrasive material A: The raw materials for the required ceramic components are selected according to the stoichiometric ratio. The raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconia balls are mixed in the specified ratio and ball-milled for 8 hours to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconia balls is 1.2:1.5:2.5. The raw material A was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 700°C for 6 hours to obtain polycrystalline material A. Take out polycrystalline material A and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 60 minutes to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:1. S2. Preparation of abrasive material B: The raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconium oxide balls were mixed in a certain proportion and ball-milled for 6 h to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was 1.5:1.5:2. The raw material B was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 750°C for 6 hours to obtain polycrystalline material B. Take out polycrystalline material B and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 120 minutes to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:1. S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a high-temperature furnace for pre-firing. The heating rate is 100℃ / h, and the temperature is held at 700℃ for 4h to obtain sintered pre-synthetic material C. S4. Grinding and sieving: The pre-synthetic material C obtained in step S3 is crushed and added to anhydrous ethanol as a dispersant. The mixture is then placed in a ball mill jar and ball-milled for 6 hours to obtain powder D. The mass ratio of the synthetic material C, anhydrous ethanol and zirconium oxide balls is 2:1:3. S5. Grinding and granulation: The powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then granulated by sieving through a 60-mesh sieve to ensure uniform powder particles; the mass fraction of the PVA colloid is 5%. S6, Tableting and dispensing: The granules obtained from step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press; the sheets are then held at 200℃ for 40 min to drain the water, and then held at 650℃ for 60 min to remove the binder, thus obtaining the corresponding ceramic sample. The cylindrical sheet is then placed in a high-temperature furnace; in this step, the drainage process is carried out at a heating rate of 5℃ / min; the binder removal process is carried out at a heating rate of 8℃ / min. S7, Sintering: The sample obtained after debinding in step S6 was sintered at a temperature of 1100℃ for 2 hours. The heating rate during sintering was 4℃ / min and the cooling rate was 3℃ / min. Figure 3 This is the hysteresis loop diagram of the potassium tantalate niobate ceramic prepared in Example 3 of the present invention. The potassium tantalate niobate ceramic exhibits a typical ferroelectric hysteresis loop, with saturation polarization close to ±60 μC / cm. 2 The coercive field is approximately ±200 kV / cm, and the ferroelectric properties are excellent.

[0037] Example 4 A potassium tantalate niobate ceramic K 1+Z-Y Ru Y Ta 1-x Nb x O3, where X=0.42, Z=0.15, Y=0.45.

[0038] The above-mentioned method for preparing potassium tantalate niobate ceramics, using high-purity K₂CO₃, Ru₂CO₃, Nb₂O₅, and Ta₂O₅ as raw materials, specifically includes the following steps: S1. Preparation of abrasive A: The raw materials for the required ceramic components are selected according to the stoichiometric ratio. The raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconia balls are mixed in the specified ratio and ball-milled for 8 hours to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconia balls is 1.3:1.5:2.5. The raw material A was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 700°C for 6 hours to obtain polycrystalline material A. Take out polycrystalline material A and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 60 minutes to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:1. S2. Preparation of abrasive material B: The raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconium oxide balls were mixed in a certain proportion and ball-milled for 6 h to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was 1:1.5:2. The raw material B was placed in a ceramic crucible and pre-sintered in a muffle furnace. It was then sintered at 750°C for 6 hours to obtain polycrystalline material B. Take out polycrystalline material B and perform wet grinding in an agate mortar and pestle, using anhydrous ethanol as the dispersion medium, and continue grinding for 120 minutes to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:1. S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a high-temperature furnace for pre-firing. The heating rate is 100℃ / h, and the temperature is held at 720℃ for 4h to obtain sintered pre-synthetic material C. S4. Grinding and sieving: The pre-synthetic material C obtained in step S3 is crushed and added to anhydrous ethanol as a dispersant. The mixture is then placed in a ball mill jar and ball-milled for 6 hours to obtain powder D. The mass ratio of the synthetic material C, anhydrous ethanol and zirconium oxide balls is 2:1:3. S5. Grinding and granulation: The powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then granulated by sieving through a 60-mesh sieve to ensure uniform powder particles; the mass fraction of the PVA colloid is 5%. S6, Tableting and dispensing: The granules obtained from granulation in step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press; the sheets are then drained by holding at 200℃ for 40 min, and then debinded by holding at 650℃ for 60 min to obtain the corresponding ceramic sample. The cylindrical sheets are then placed in a high-temperature furnace. In this step, the drainage process is carried out at a heating rate of 4℃ / min, and the debinding process is carried out at a heating rate of 7℃ / min. S7, Sintering: The debinding sample obtained in step S6 was sintered at a temperature of 1200℃ for 2 hours. The heating rate during sintering was 4℃ / min, and the cooling rate was 2℃ / min. Figure 4 The above-mentioned ceramic leakage current diagram shows that the leakage current is low and the ceramic has good electrical properties.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A potassium tantalate-niobate ceramic, characterized in that: Its chemical formula For K 1+Z-Y Ru Y Ta 1-x Nb x O3, where 0.38≤X≤0.42, 0.10≤Z≤0.20, and 0.35≤Y≤0.

50.

2. The potassium tantalate niobate ceramic according to claim 1, characterized in that: When the amount of Nb is 0.38≤x<0.40 and Z is 0.10≤Z<0.15, the doping concentration ratio X / Z is 2.5-4; when the amount of Nb is 0.40≤X≤0.42 and Z is 0.15≤Z≤0.2, the doping concentration ratio X / Z is 2-2.

8.

3. The method for preparing potassium tantalate niobate ceramic according to any one of claims 1-2, characterized in that, Includes the following steps: According to K 1+Z-Y Ru Y Ta 1-x Nb x The stoichiometric ratio of O3 is used to select the raw materials for the required ceramic components: K2CO3, Ru2CO3, Nb2O5, and Ta2O5. S1. Preparation of abrasive material A: Raw materials Nb2O5, Ta2O5, anhydrous ethanol and zirconium oxide balls were mixed and ball-milled to obtain raw material A, wherein the mass ratio of (Nb2O5+Ta2O5): anhydrous ethanol: zirconium oxide balls was (1-1.5):1.5:2.

5. The raw material A is pre-sintered to obtain polycrystalline material A; Polycrystalline material A is taken out and wet-milled using anhydrous ethanol as the dispersion medium to obtain grinding material A. The mass ratio of polycrystalline material A to anhydrous ethanol is 2:

1. S2. Preparation of abrasive material B: Raw materials K2CO3, Ru2CO3, anhydrous ethanol and zirconia balls were mixed and ball-milled to obtain raw material B, wherein the mass ratio of (K2CO3+Ru2CO3):anhydrous ethanol:zirconia balls was (1-1.5):1.5:2; The raw material B is pre-sintered to obtain polycrystalline material B; Take out polycrystalline material B and perform wet grinding with anhydrous ethanol as the dispersion medium to obtain grinding material B. The mass ratio of polycrystalline material B to anhydrous ethanol is 3:

1. S3, Sintering Pre-synthesis: The grinding material A obtained in step S1 and the grinding material B obtained in step S2 are mixed evenly, compacted, and placed in a furnace for pre-firing. The heating rate is 80-100℃ / h, and the temperature is held at 700-720℃ for 4h to obtain sintered pre-synthetic material C. S4. Grinding: The pre-synthesized material C obtained in step S3 is ball-milled and sieved to obtain powder D; S5, Granulation: The powder D obtained in step S4 is added to PVA colloid and granulated. S6, Tableting and dispensing: The granules granulated in step S5 are pressed into tablets; the tablets are kept at 200℃ for 40 min to drain the water, and then kept at 650℃ for 60 min to remove the binder, and the corresponding ceramic samples are placed in a high-temperature furnace. When 0.35≤Y≤0.40, the drainage process has a heating rate of 2-3℃ / min; the glue discharge rate has a heating rate of 5-6℃ / min. When 0.40 < Y ≤ 0.50, the drainage process is heated at a rate of 4-5℃ / min; the glue discharge rate is heated at a rate of 7-8℃ / min. S7, Sintering: The sample obtained after debinding in step S6 is sintered at a temperature of 1100-1200℃ for 2 hours.

4. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: In S1, ball milling is performed for 8 hours and wet grinding for 60 minutes; in S2, ball milling is performed for 6 hours and wet grinding for 120 minutes.

5. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: In S1, the material is pre-sintered at 700°C for 6 hours; in S2, the material is pre-sintered at 750°C for 6 hours.

6. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: In step S4, the pre-synthetic material C obtained in step S3 is crushed, anhydrous ethanol is added as a dispersant, and the mixture is placed in a ball mill jar and ball-milled for 6 hours to obtain powder D; wherein the mass ratio of the synthetic material C: anhydrous ethanol: zirconium oxide balls is 2:1:

3.

7. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: In step S5, the powder D obtained in step S4 is added to PVA colloid, and after injection, it is thoroughly ground and then sieved through a 60-mesh sieve for granulation; the mass fraction of the PVA colloid is 5%.

8. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: In step S6, the granulated particles from step S5 are pressed into cylindrical sheets with a diameter of 10 mm and a thickness of 1 mm using a hydraulic press.

9. The method for preparing potassium tantalate niobate ceramic according to claim 3, characterized in that: When 0.10≤Z<0.13, in step S7, the heating rate of the sintering process is 5-6℃ / min and the cooling rate is 7-9℃ / min; When 0.13≤Z≤0.2, in step S7, the heating rate of the sintering process is 4-4.8℃ / min, and the cooling rate is 2-3℃ / min.

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