Zirconia ceramic powder and preparation method therefor, and zirconia sintered body

Abstract

The present disclosure relates to the technical field of zirconia. Disclosed are a zirconia ceramic powder and a preparation method therefor, and a zirconia sintered body. The zirconia ceramic powder comprises a solid solution formed by zirconia and a stabilizer. The specific surface area of the zirconia ceramic powder is 10-32 m2 / g, the average particle diameter D50 thereof is 0.1-0.3 μm, and the average particle diameter D90 thereof is 0.2-0.5 μm. The peak intensity ratio of the crystal grain 220 crystal plane / 200 crystal plane of the zirconia ceramic powder obtained by means of powder X-ray diffraction measurement is 1.2-2.5. The average crystallite diameter of the grains of the zirconia ceramic powder obtained by means of (-111) plane peaks of the grains of the zirconia ceramic powder in the X-ray diffraction measurement is 150-550 Å. The zirconia ceramic powder satisfying the numerical ranges has a specific crystal plane orientation, such that low-temperature sintering can be achieved without adding a sintering aid, and a sintered body having high strength and a high sintering density can be obtained.

Description

A zirconia ceramic powder, its preparation method, and zirconia sintered body

[0001] This disclosure claims priority to Chinese Patent Application No. 202411883228X, filed on December 19, 2024, entitled "A Zirconia Ceramic Powder and its Preparation Method and a Zirconia Sintered Body", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of zirconia technology, and more specifically, to a zirconia ceramic powder, a method for preparing the same, and a zirconia sintered body. Background Technology

[0003] Zirconia is widely used in crushing, optics, decoration, and dentistry. Currently, the sintering temperature of dental zirconia is around 1500℃, which consumes a certain amount of energy. Moreover, with the development of dental zirconia, higher requirements are being placed on aesthetics and performance. Existing high-temperature sintered zirconia cannot meet the growing demands in terms of transparency, strength, and low-temperature aging performance.

[0004] Comparing this to patent document 1 (CN113200567A), which discloses a highly sinterable active zirconia powder, the zirconia powder has a particle size of 50-150 nm and a sintering density of 6.051-6.083 g / cm³ at 1350-1450 °C. 3 This patent employs a combination of liquid-phase precipitation and hydrothermal methods, performing a dry-wet gel conversion after liquid-phase precipitation and before the hydrothermal reaction to prepare homogeneously dispersed tetragonal zirconia powder. However, this method is more complex than directly using the hydrothermal method to prepare zirconia, and it does not investigate the ceramic density below 1350℃.

[0005] Compared with Patent Document 2 (JP2023171832A), a zirconia powder is disclosed, which contains at least one of yttrium oxide, calcium oxide, magnesium oxide and cerium oxide as a stabilizer. The proportion of monoclinic crystals in the zirconia powder crystal phase is less than 0.5%, the average particle size is less than 0.5 μm, and the volume particle size is 100% particles of less than 1 μm. This patent can achieve a sintering temperature of more than 1200°C and less than 1600°C in an air atmosphere by controlling the zirconia crystal phase composition and particle size distribution, and the strength is between 350-600 MPa.

[0006] The ceramic sintering process transforms the point-contact accumulation of particles into surface contact, simultaneously eliminating interparticle pores and resulting in dense sintered ceramics. Therefore, the sintering activity of ceramics is influenced by particle size and interparticle porosity. The particle size tested in Reference Document 1 is the secondary particle size; however, secondary particles are aggregates of primary particles, and the agglomeration behavior of primary particles and the presence of sintering necks all affect the secondary particle test. Reference Document 2 studies the sintering activity by controlling the size and distribution of the gaps between primary particles. In summary, improving sintering activity relies not only on the particle size and distribution of secondary particles and the uniformity of the primary particles constituting the secondary particles, as well as the degree of coarse or dense packing, but also on controlling the primary particle size to obtain highly sinterable zirconia powder. Furthermore, Reference Documents 1 and 2 only indicate that the powder has high sintering activity but do not directly study the sintering activity itself.

[0007] In view of this, this disclosure is hereby made.

[0008] Public content

[0009] The purpose of this disclosure is to provide a zirconia ceramic powder, its preparation method, and a zirconia sintered body. This disclosure limits the specific surface area, particle size, peak intensity ratio of 220 crystal planes to 200 crystal planes, and average microcrystal diameter of the zirconia ceramic powder to obtain a zirconia ceramic powder that can be sintered at low temperature under normal pressure and has a high sintering density. Since the zirconia ceramic powder is a nanoparticle, the scattering cross section is small, the scattering at the grain boundaries is reduced, the tetragonality is smaller, resulting in less birefringence, and the light transmittance of the obtained zirconia ceramic is improved, while also having high strength.

[0010] This disclosure is implemented as follows:

[0011] In a first aspect, this disclosure provides a zirconia ceramic powder comprising a solid solution of zirconia and a stabilizer, wherein the zirconia ceramic powder has a specific surface area of ​​10–32 m². 2 / g, with an average particle size D50 of 0.1–0.3 μm and an average particle size D90 of 0.2–0.5 μm. The peak intensity ratio of the 220 / 200 crystal planes of the zirconia ceramic powder, determined by powder X-ray diffraction, is 1.2–2.5. The average crystallite diameter of the zirconia ceramic powder, obtained from the (-111) plane peak of the zirconia ceramic powder grains by X-ray diffraction, is [missing value].

[0012] In an optional embodiment, the 2θ angle corresponding to the 220 crystal plane is 49.5° to 50.5°, the 2θ angle corresponding to the 200 crystal plane is 29.5° to 30.5°, and the 2θ angle corresponding to the (-111) crystal plane is 31° to 32°.

[0013] In an optional embodiment, the sintering initiation point of the zirconia ceramic powder is below 1300°C, and the sintering initiation point is obtained based on DIL testing.

[0014] In an optional embodiment, the stabilizer includes at least one of a Y source, a Ca source, a Mg source, and an Er source;

[0015] Optionally, the Y source includes one or more of yttrium oxide, yttrium nitrate, yttrium chloride, and yttrium sulfate; optionally, the content of the Y source relative to the zirconia ceramic powder is 1.5 to 5 mol%.

[0016] Optionally, the Ca source includes one or more of calcium oxide, calcium carbonate, and calcium chloride; optionally, the content of the Ca source relative to the zirconia ceramic powder is 4-8 mol%.

[0017] Optionally, the Mg source includes one or more of magnesium oxide, magnesium chloride, and magnesium sulfate; optionally, the content of the Mg source relative to the zirconia ceramic powder is 6-13 mol%.

[0018] Optionally, the Er source is erbium oxide; optionally, the content of the Er source relative to the total zirconium oxide powder is 3-5 mol%.

[0019] In an optional embodiment, the zirconia ceramic powder further includes at least one of a first dopant of 0.005-1 wt% that produces a coloring effect and a second dopant of 0.005-1 wt% that improves toughness and low-temperature aging resistance;

[0020] Optionally, the first dopant includes at least one of Fe, Er, Mn, Co, Cr, Tb, Pr, Nd, Eu, and Ti;

[0021] Optionally, the second dopant is Al;

[0022] Optionally, the Al includes one or more of aluminum oxide, aluminum chloride, and aluminum nitrate.

[0023] Secondly, this disclosure provides a method for preparing zirconia ceramic powder as described in any of the foregoing embodiments, comprising:

[0024] S1. Prepare a solution of soluble zirconium salt with a zirconium ion concentration of 0.3-0.7 mol / L, and perform hydrothermal reaction for 12-50 h under the conditions of pressure of 0.2-0.35 MPa and temperature of 120-140℃. Add a stabilizer to the product to obtain the reaction solution.

[0025] S2. The reaction solution is dried and then calcined at a temperature of 950-1150℃, a heating rate of 2.5-6℃ / min, and a holding time of 1-5h to obtain calcined powder.

[0026] S3. The calcined powder is ball-milled to obtain zirconia ceramic powder for 0.5-6 hours.

[0027] In an optional embodiment, the zirconium salt includes at least one of zirconium oxychloride, zirconium acetate, and zirconium carbonate.

[0028] Thirdly, this disclosure provides a zirconia sintered body, which comprises zirconia ceramic powder prepared by the zirconia ceramic powder as described in the foregoing embodiments or by the zirconia ceramic powder preparation method as described in any one of the foregoing embodiments, and is formed by atmospheric pressure sintering.

[0029] In an optional embodiment, the atmospheric pressure sintering includes sequentially performing dry pressing, isostatic pressing, pre-sintering, and sintering.

[0030] Optionally, the dry pressing pressure is 120-300MPa and the dry pressing time is 30-180s;

[0031] Optionally, the isostatic pressing pressure is 150-350 MPa and the isostatic pressing time is 5-20 min.

[0032] Optionally, the pre-sintering temperature is 800-1100℃, and the pre-sintering time is 15h-60h;

[0033] Optionally, the sintering temperature is 1150℃-1400℃, and the sintering time is 30min-10h.

[0034] In an optional embodiment, the sintered density of the zirconia sintered body is ≥99%, the strength is 700-1300 MPa, and the permeability is 38-44%.

[0035] This disclosure has at least the following beneficial effects:

[0036] This disclosure provides a zirconia ceramic powder having a specific surface area of ​​10–32 m². 2 / g, with an average particle size D50 of 0.1–0.3 μm and an average particle size D90 of 0.2–0.5 μm. The peak intensity ratio of the 220 / 200 crystal planes of the zirconia ceramic powder, determined by powder X-ray diffraction, was 1.2–2.5. The average crystallite diameter of the zirconia ceramic powder, obtained from the (-111) plane peaks of the zirconia ceramic powder grains by X-ray diffraction, was [missing value]. The particle size (D50) of zirconia ceramic powder affects its specific surface area and sintering activity, thus influencing the solid-state diffusion rate and the interaction between sintered particles during sintering. Smaller particle sizes result in larger specific surface areas, increasing the contact area between powder particles, improving the solid-state diffusion rate, and enhancing sintering activity, leading to relatively lower sintering temperatures. Simultaneously, the particle size (D90) needs to be controlled; excessively large D90 indicates the presence of numerous large particles, causing molding defects and affecting sintering performance, strength, and permeability. A peak intensity ratio of 220° crystal facets to 200° crystal facets controlled within the range of 1.2-2.5 ensures that the molded body does not easily disintegrate and exhibits excellent sintered body strength. The average crystallite diameter is within... This method ensures minimal grain porosity defects, effectively preventing impacts on the strength and permeability of the sintered body, and enabling low-temperature sintering at 1150-1400℃, thus reducing energy consumption. This disclosure controls the specific surface area, particle size, peak intensity ratio of the 220 crystal plane to the 200 crystal plane, and average crystallite diameter of the zirconia ceramic powder. Zirconia ceramic powder meeting these numerical ranges exhibits specific crystal orientations, allowing for low-temperature sintering without the addition of sintering aids, and yielding sintered bodies with high strength and high sintering density. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 is a DIL curve of the zirconia ceramic powder provided in Embodiment 1 of this disclosure;

[0039] Figure 2 is a DIL curve of the zirconia ceramic powder provided in Embodiment 3 of this disclosure;

[0040] Figure 3 is a DIL curve of the zirconia ceramic powder provided in Embodiment 8 of this disclosure;

[0041] Figure 4 is a DIL curve of the zirconia ceramic powder provided in Embodiment 12 of this disclosure;

[0042] Figure 5 is a DIL curve of the zirconia ceramic powder provided in Comparative Example 1 of this disclosure;

[0043] Figure 6 is a DIL curve of the zirconia ceramic powder provided in Comparative Example 4 of this disclosure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0045] This disclosure provides a zirconia ceramic powder comprising a solid solution of zirconia and a stabilizer, wherein the specific surface area of ​​the zirconia ceramic powder is 10–32 m². 2 / g, with an average particle size D50 of 0.1–0.3 μm and an average particle size D90 of 0.2–0.5 μm. The peak intensity ratio of the 220 / 200 crystal planes of the zirconia ceramic powder, determined by powder X-ray diffraction, was 1.2–2.5. The average crystallite diameter of the zirconia ceramic powder, obtained from the (-111) plane peaks of the zirconia ceramic powder grains by X-ray diffraction, was [missing value].

[0046] In this disclosure, the specific surface area, particle size, peak intensity ratio of 220 crystal planes to 200 crystal planes, and average crystallite diameter of zirconia ceramic powder are controlled. Zirconia ceramic powder that meets the above numerical range has a specific crystallographic orientation, so low-temperature sintering can be achieved without adding sintering aids, and sintered bodies with high strength and high sintering density can be obtained.

[0047] In some typical but non-limiting examples, the specific surface area of ​​zirconia ceramic powder can be, for example, 10 m². 2 / g、12m 2 / g, 15m 2 / g、18m 2 / g、20m 2 / g、25m 2 / g、18m 2 / g、30m 2 / g and 32m 2 The range of values ​​in / g, either one or both.

[0048] In some typical but non-limiting examples, the average particle size D50 of the zirconia ceramic powder can be, for example, a range of any one of 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, and 0.3 μm, or any two of them.

[0049] In some typical but non-limiting examples, the average particle size D90 of the zirconia ceramic powder can be, for example, any one of 0.2 μm, 0.3 μm, 0.4 μm, and 0.5 μm, or a range between any two.

[0050] In some typical but non-limiting examples, the peak intensity ratio of the 220 crystal planes to the 200 crystal planes of the zirconia ceramic powder, as determined by powder X-ray diffraction, can be, for example, a range of any one of 1.2, 1.5, 1.8, 2.0, 2.2, 2.4, and 2.5, or any two of them.

[0051] In some typical but non-limiting examples, the average crystallite diameter of zirconia ceramic powder obtained by X-ray diffraction determination of the (-111) plane peak of the zirconia ceramic powder grains can be, for example, and The range of values ​​between any one or any two of them.

[0052] Specifically, the particle size D50 of zirconia ceramic powder affects its specific surface area and sintering activity, thus influencing the solid-phase diffusion rate and the interaction between sintered particles during sintering. Smaller particle sizes result in larger specific surface areas, increasing the contact area between powder particles, improving the solid-phase diffusion rate, and enhancing sintering activity, leading to relatively lower sintering temperatures. Simultaneously, the particle size D90 needs to be controlled. Excessively large D90 indicates the presence of many large particles, causing molding defects and affecting sintering performance, strength, and permeability. If the particle size is too small and the specific surface area is too large: After calcination, these small particles are prone to agglomeration due to their high surface energy, resulting in poor dispersion. Furthermore, the resulting powder exhibits poor formability when used to prepare sintered bodies, deteriorating strength, permeability, and toughness. Conversely, if the particle size is too large and the specific surface area is too small: Larger particle sizes result in smaller specific surface areas, lower surface energy, slower solid-phase migration rates, and difficulty in sintering at low temperatures, leading to decreased permeability and strength.

[0053] The peak intensity ratio ((220) / (200)) of the 220 crystal plane to the 200 crystal plane of zirconia ceramic powder grains is 1.2-2.5. When it is greater than the upper limit, the particles are prone to disintegration during molding; when it is less than the lower limit, the strength of the sintered body shows a decreasing trend. Among them, the 2θ angle corresponding to the 220 crystal plane is 49.5° to 50.5°, and the 2θ angle corresponding to the 200 crystal plane is 29.5° to 30.5°.

[0054] The average crystallite diameter of the primary particles of the zirconia ceramic powder was determined by analyzing the (-111) plane peaks of the zirconia ceramic powder grains using powder X-ray diffraction. When the average crystallite diameter is too large, the zirconia grains grow excessively, resulting in increased intergranular gaps. This affects formability by increasing porosity and defects, impacting the strength and translucency of the sintered body. Furthermore, it reduces intergranular contact, weakening energy transfer during sintering and making low-temperature sintering difficult. When the average crystallite diameter is too small, the grain boundaries increase. Incident light passing through these boundaries inevitably causes continuous reflection and refraction, reducing light transmittance. The 2θ angle corresponding to the (-111) crystal plane is 31°–32°.

[0055] In some embodiments, the sintering initiation point of the zirconia ceramic powder is below 1300°C, and the sintering initiation point is obtained based on DIL testing. By screening the sintering activity, it is possible to obtain zirconia sintered bodies with high strength and high sintering density under low temperature conditions of 1150°C-1400°C.

[0056] Stabilizers include, but are not limited to, at least one of Y source, Ca source, Mg source and Er source.

[0057] In some embodiments, the Y source includes, but is not limited to, one or more of yttrium oxide, yttrium nitrate, yttrium chloride, and yttrium sulfate; optionally, the content of the Y source relative to the zirconia ceramic powder is 1.5 to 5 mol%; for example, it can be any one of 1.5 mol%, 2 mol%, 2.5 mol%, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, or a range between any two.

[0058] In some embodiments, the Ca source includes, but is not limited to, one or more of calcium oxide, calcium carbonate, and calcium chloride; optionally, the content of the Ca source relative to the zirconia ceramic powder is 4 to 8 mol%. For example, it can be any one of 4 mol%, 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, or a range between any two.

[0059] In some embodiments, the Mg source includes, but is not limited to, one or more of magnesium oxide, magnesium chloride and magnesium sulfate; optionally, the content of the Mg source relative to the zirconia ceramic powder is 6 to 13 mol%; for example, it can be any one of 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, 11 mol%, 12 mol%, 13 mol%, or a range between any two.

[0060] In some embodiments, the Er source includes, but is not limited to, erbium oxide; optionally, the Er source content relative to the total zirconium oxide powder is 3 to 5 mol%. For example, it can be any one of 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, or a range between any two.

[0061] In some embodiments, the zirconia ceramic powder further includes at least one of a first dopant of 0.005-1 wt% that produces a coloring effect and a second dopant of 0.005-1 wt% that improves toughness and low-temperature aging resistance;

[0062] Optionally, the first dopant includes, but is not limited to, at least one of Fe, Er, Mn, Co, Cr, Tb, Pr, Nd, Eu, and Ti; the second dopant is Al; Al includes, but is not limited to, one or more of aluminum oxide, aluminum chloride, and aluminum nitrate.

[0063] The first and second dopants mentioned above can be added to the zirconia ceramic powder at any stage of the preparation process. The first and second dopants can be partially loaded on the surface of zirconia and partially form a composition with zirconia alone; or they can be completely free and form a composition with zirconia alone.

[0064] This disclosure provides a method for preparing zirconia ceramic powder, which includes the following steps:

[0065] S1. Prepare a solution of soluble zirconium salt with a zirconium ion concentration of 0.3-0.7 mol / L, and perform a hydrothermal reaction at a pressure of 0.2-0.35 MPa and a temperature of 120-140℃ for 12-50 h. Add a stabilizer to the product to obtain a reaction solution. The zirconium salt includes at least one of zirconium oxychloride, zirconium acetate and zirconium carbonate.

[0066] S2. After drying the reaction solution, calcination is carried out at a temperature of 950-1150℃, a heating rate of 2.5-6℃ / min, and a holding time of 1-5h to obtain calcined powder.

[0067] S3. The calcined powder is ball-milled to obtain zirconia ceramic powder for 0.5-6 hours.

[0068] In this disclosure, by controlling the concentration of the zirconium salt solution and the conditions of the hydrothermal reaction, better zirconium oxide particle size, specific surface area and crystallinity can be obtained. By adding a stabilizer to the product, a solid solution is formed with zirconium oxide during subsequent drying and calcination. Zirconia ceramic powder can be obtained by grinding.

[0069] In this disclosure, the concentration of the zirconium salt solution and the conditions of the hydrothermal reaction need to be strictly controlled. If the concentration of the zirconium salt solution is too high, it will lead to more nucleation in the reaction system, and the grains will be too fine and prone to agglomeration. If the concentration of the solution is too low, there will be fewer nucleation, and the grains will easily grow, resulting in reduced activity. If the hydrothermal temperature is too low, the pressure is too low, or the reaction time is too short, it will lead to incomplete grain development, excessive hydrates, and severe adhesion and agglomeration. If the hydrothermal temperature is too high, the pressure is too high, or the reaction time is too long, the grains will continue to grow, and the activity of the powder will decrease.

[0070] Furthermore, this disclosure provides a zirconia sintered body, which comprises being formed by constant pressure sintering of the aforementioned zirconia ceramic powder.

[0071] Atmospheric pressure sintering includes sequential dry pressing, isostatic pressing, pre-sintering, and sintering. Specifically, atmospheric pressure sintering involves first dry pressing at 120-300 MPa for 30-180 seconds, then isostatic pressing at 150-350 MPa for 5-20 minutes, followed by pre-sintering at 800-1100℃ for 15-60 hours, and finally sintering at 1150℃-1400℃ for 30 minutes-10 hours, yielding a high-density zirconia sintered body. The sintered density of the zirconia sintered body is ≥99%, with a strength of 700-1300 MPa and a permeability of 38-44%.

[0072] The features and performance of this disclosure will be further described in detail below with reference to embodiments.

[0073] This disclosure provides zirconia ceramic powder, zirconia pre-fired body and zirconia sintered body as shown in Tables 1 and 2, and tests them.

[0074] The detection methods include:

[0075] (1) Specific surface area determination: Measured using a specific surface area analyzer by the BET method.

[0076] (2) Particle size determination: Particle size distribution was determined using a laser particle size analyzer.

[0077] (3) Peak intensity and grain size determination: The crystal structure of solid powder was determined by X-ray diffraction.

[0078] (4) Sintering activity determination: The DIL method was used to test the sintering activity using a high-temperature thermal expansion apparatus. The results are shown in Table 1 and Figures 1-6.

[0079] (5) Preparation and determination of zirconia sintered body: The zirconia pre-sintered bodies of the examples and comparative examples were sintered according to the heating program. The heating program was to raise the temperature to 1200℃ at 10℃ / min and hold for 2h, and then raise the temperature to the sintering temperature at 5℃ / min and hold for 2h.

[0080] The relative sintered density of the zirconia sintered body is obtained by the following method:

[0081] Relative sintering density (%) = (actual sintering density / theoretical sintering density) × 100;

[0082] The theoretical sintering density (denoted as ρ0) is calculated using the following formula (1): ρ0=100 / [(Y / 3.987)+(100-Y) / ρz] (1);

[0083] Where Y is the alumina concentration (wt%), and ρz is the value calculated by the following formula (2): ρz=[124.25(100-X)+[molecular weight of stabilizer]× X] / [150.5(100+X)A 2 C] (2);

[0084] In formula (2), the molecular weight of the stabilizer is 225.81 when the stabilizer is Y2O3 and 382.52 when the stabilizer is Er2O3. X is the stabilizer concentration (mol%).

[0085] In addition, A and C are calculated using the following formulas (3) and (4), respectively. A = 0.5080 + 0.06980X / (100 + X) (3); C = 0.5195 - 0.06180X / (100 + X) (4);

[0086] In equation (1), the theoretical sintered density varies depending on the powder composition. For example, it is 6.098 g / cm³ when the yttrium oxide content is 3 mol%. 3 The concentration was 6.051 g / cm³ when the yttrium oxide content was 5.5 mol%. 3 (When Al2O3 = 0% by weight).

[0087] When the stabilizer is CaO, ρz is calculated using the following formula (5): ρz = -0.0400 (molar concentration of CaO) + 6.1700 (5).

[0088] Furthermore, the theoretical sintering density (denoted as ρ1) when containing colorant is calculated as follows: ρ1=100 / [(Z / V)+(100-Z) / ρ0] (6);

[0089] Where Z is the colorant concentration (wt%), and V is the theoretical density of the colorant (g / cm³). 3 Regarding the theoretical density of the colorant, Fe2O3 is 5.24 g / cm³. 3 Er2O3 was 8.64 g / cm³. 3 MnO2 is 5.03 g / cm³. 3 CoO is 6.10 g / cm³ 3 The Cr2O3 concentration was 5.22 g / cm³. 3 Tb4O7 is 7.80 g / cm³. 3The Pr₂O₃ concentration was 7.13 g / cm³. 3 The Nd₂O₃ concentration was 7.24 g / cm³. 3 Eu2O3 was 7.42 g / cm³. 3 TiO2 content is 4.23 g / cm³. 3 .

[0090] The actual sintering density of the zirconia sintered body was tested using the Archimedes displacement method.

[0091] Strength was tested using a universal testing machine via the three-point bending strength method. Light transmittance was tested using a benchtop visible spectrophotometer via the spectrophotometric method.

[0092] Please refer to Tables 1 and 2 for the test results.

[0093] Table 1. Indicators of Zirconia Ceramic Powder

[0094] Table 2. Performance parameters of zirconia pre-sintered and sintered bodies

[0095] Regarding the light transmittance of Examples 10, 11, and 13: The addition of colorant forms a solid solution, causing changes in the grain boundary structure. Incident light undergoes irregular reflection, refraction, and scattering when passing through the grain boundaries, resulting in reduced light transmittance. In Comparative Example 9, compared to Example 10, only the ball milling time was changed, yet the performance was significantly deteriorated, with a marked decrease in light transmittance.

[0096] As can be seen from Tables 1-2 above, when the specific surface area, particle size, crystal peak intensity and grain size of zirconia ceramic powder are within the range of this disclosure, its initial sintering temperature is significantly lower than that of Comparative Examples 1-4, and the sintering density, strength and light transmittance of the zirconia sintered body are also significantly better than those of Comparative Examples 1-4.

[0097] The particle size (D50) of ceramic powder affects its specific surface area and sintering activity, thus influencing the solid-phase diffusion rate and the interaction between sintered particles during sintering. Specifically, smaller particle sizes result in larger specific surface areas, increasing the contact area between powder particles, improving the solid-phase diffusion rate, and enhancing sintering activity, leading to relatively lower sintering temperatures. Simultaneously, the particle size (D90) needs to be controlled. Excessively large D90 indicates the presence of numerous large particles, causing molding defects and consequently affecting sintering performance, strength, and permeability.

[0098] Particle size too small, specific surface area too large: Particles with too small a size are prone to agglomeration after calcination and dispersion due to their high surface energy, resulting in poor dispersion effect. Furthermore, the corresponding powder has poor formability when preparing sintered bodies, deteriorating strength, permeability, and toughness.

[0099] Large particle size and small specific surface area: Powders with large particle size have small specific surface area, low surface energy, slow solid phase migration rate, are not easy to sinter at low temperature, and have poor permeability strength.

[0100] The average crystallite diameter of the above-mentioned primary zirconia particles was determined by analyzing the (-111) plane peaks of the zirconia grains using powder X-ray diffraction. When the average crystallite diameter is too large, the zirconia grains grow excessively, resulting in increased intergranular gaps. This affects formability by increasing porosity and defects, impacting the strength and translucency of the sintered body. Furthermore, it reduces intergranular contact, weakening energy transfer during sintering and making low-temperature sintering difficult. When the average crystallite diameter is too small, the grain boundaries increase. Incident light passing through these boundaries inevitably causes continuous reflection and refraction, reducing light transmittance.

[0101] The peak intensity ratio ((220) / (200)) of the 220 crystal plane of zirconia grains is 1.2-2.5. When it is greater than the upper limit, the particles are prone to disintegration during molding. When it is less than the lower limit, the strength of the sintered body shows a downward trend.

[0102] In addition, this disclosure also provides preparation methods for the above-mentioned product embodiments and product comparative examples.

[0103] Method Example 1

[0104] 58.57 g of zirconium carbonate was dissolved in 1 L of pure water to prepare a solution with a zirconium ion concentration of 0.3 mol / L. The solution was then subjected to hydrothermal reaction at a pressure of 0.24 MPa and a temperature of 120 °C for 16 h. 1.11 g (3 mol%) of yttrium oxide was added to the product as a stabilizer. The resulting reaction solution was dried and then calcined at a temperature of 1000 °C, a heating rate of 3 °C / min, and a holding time of 4 h. Subsequently, the solution was ball-milled for 0.5 h to obtain zirconium oxide ceramic powder.

[0105] Zirconia ceramic powder was dry-pressed at 120 MPa for 120 s, then isostatically pressed at 180 MPa for 12 min, and pre-sintered at 1000 °C for 40 h to obtain the zirconia pre-sintered body of Example 1. The zirconia pre-sintered body was sintered at 1250 °C for 5 h to achieve a relative sintering density of 99.6%.

[0106] Method Example 2

[0107] This embodiment is basically the same as the method embodiment 1, except that 58.57g of zirconium carbonate is replaced with 136.66g of zirconium carbonate, that is, the zirconium ion concentration is replaced with 0.7mol / L. The zirconium oxide ceramic powder and zirconium oxide pre-sintered body of embodiment 2 are obtained in the same manner as in embodiment 1. The zirconium oxide pre-sintered body is sintered at 1250℃ to achieve a dense structure with a relative sintering density of 99.5%.

[0108] Method Example 3

[0109] This embodiment is basically the same as Method Example 1, except that 58.57g of zirconium carbonate was replaced with 66.35g of zirconium oxychloride and the pressure was changed to 0.35MPa. The zirconium oxide ceramic powder of Example 3 was obtained in the same manner as in Example 1. The zirconium oxide pre-fired body of Example 3 was obtained by replacing the pre-firing temperature with 1100℃. The zirconium oxide pre-fired body was sintered at 1350℃ to achieve a dense structure with a relative sintering density of 99.8%.

[0110] Method Example 4

[0111] This embodiment is basically the same as the method embodiment 1, except that the hydrothermal reaction temperature is replaced with 140°C and the hydrothermal time is replaced with 50h. The zirconia ceramic powder and zirconia pre-sintered body of embodiment 4 are obtained in the same manner as in embodiment 1. The zirconia pre-sintered body is sintered at 1350°C to achieve a dense structure with a relative sintering density of 99.7%.

[0112] Method Example 5

[0113] This embodiment is basically the same as Method Example 1, except that the stabilizer was replaced with 1.85g (5mol%) yttrium oxide and the calcination temperature was replaced with 1050℃, and the zirconia ceramic powder of Example 5 was obtained in the same manner as in Example 1; except that the pre-calcination temperature was replaced with 900℃, the zirconia pre-calcined body of Example 5 was obtained, which was sintered at 1150℃ to achieve a dense structure with a relative sintering density of 99.6%.

[0114] Method Example 6

[0115] This embodiment is basically the same as the method embodiment 1, except that the hydrothermal time is replaced with 130°C and the stabilizer is replaced with 0.93g (1.5mol%) of yttrium oxide. The zirconia ceramic powder and zirconia pre-sintered body of embodiment 6 were obtained in the same manner as in embodiment 1. The zirconia pre-sintered body was sintered at 1400°C to achieve a dense structure with a relative sintering density of 99.5%.

[0116] Method Example 7

[0117] This embodiment is basically the same as the method embodiment 1, except that the stabilizer is replaced with 3.67g (5mol%) calcium chloride, the calcination temperature is replaced with 1100℃ and the ball milling time is replaced with 5h. The zirconia ceramic powder and zirconia pre-sintered body of embodiment 7 were obtained in the same manner as in embodiment 1. The zirconia pre-sintered body was sintered at 1350℃ to achieve a dense structure with a relative sintering density of 99.7%.

[0118] Method Example 8

[0119] This embodiment is basically the same as the method embodiment 1, except that the calcination temperature is replaced with 1050℃, the heating rate is replaced with 6℃ / min, and the holding time is replaced with 1h. In the same way as in embodiment 1, the zirconia ceramic powder and zirconia pre-sintered body of embodiment 8 were obtained. The zirconia pre-sintered body was sintered at 1400℃ to achieve a dense structure with a relative sintering density of 99.6%.

[0120] Method Example 9

[0121] This embodiment is basically the same as the method embodiment 1, except that the calcination temperature is replaced with 1150℃ and the ball milling time is replaced with 6h. The zirconia ceramic powder of embodiment 9 is obtained in the same manner as in embodiment 1. The zirconia pre-fired body of embodiment 9 is obtained except that the pre-firing temperature is replaced with 1050℃. The zirconia pre-fired body is sintered at 1350℃ to achieve a dense structure with a relative sintering density of 99.7%.

[0122] Method Example 10

[0123] This embodiment is basically the same as Method Example 1, except that the stabilizer is replaced with 1.48g (4mol%) yttrium oxide, the calcination temperature is replaced with 950℃, and 0.2wt% iron oxide is added. The zirconia ceramic powder of Example 10 is obtained in the same manner as in Example 1. The zirconia pre-fired body of Example 10 is obtained except that the pre-firing temperature is replaced with 850℃. The zirconia pre-fired body is sintered at 1150℃ to achieve a dense structure with a relative sintering density of 99.7%.

[0124] Method Example 11

[0125] This embodiment is basically the same as the method embodiment 1, except that the hydrothermal pressure is changed to 0.3 MPa, the hydrothermal temperature is changed to 130°C, and the stabilizer is replaced with 4 mol% of erbium oxide. The zirconia ceramic powder of embodiment 11 is obtained in the same manner as in embodiment 1. Except that the pre-firing temperature is replaced with 950°C to obtain the zirconia pre-fired body of embodiment 11, which is sintered at 1350°C to achieve a dense structure with a relative sintering density of 99.5%.

[0126] Method Example 12

[0127] This embodiment is basically the same as the method embodiment 1, except that 58.57g of zirconium carbonate was replaced with 154.83g of zirconium oxychloride and 0.1wt% of alumina was added. The zirconium oxide ceramic powder and zirconium oxide pre-sintered body of embodiment 12 were obtained in the same manner as in embodiment 1. The zirconium oxide pre-sintered body was sintered at 1150℃ to achieve a dense structure with a relative sintering density of 99.7%.

[0128] Method Example 13

[0129] This embodiment is basically the same as the method embodiment 1, except that 0.02 wt% alumina and 0.005 wt% manganese oxide are added. The zirconia ceramic powder of embodiment 13 is obtained in the same manner as in embodiment 1. The zirconia pre-sintered body of embodiment 13 is obtained except that the dry pressing pressure is replaced with 150 MPa and the isostatic pressing pressure is replaced with 240 MPa. The zirconia pre-sintered body is sintered at 1350 °C to achieve a dense structure with a relative sintering density of 99.5%.

[0130] Method Example 14

[0131] Zirconia powder was prepared by chemical precipitation: 66.35 g of zirconium oxychloride was dissolved in 1 L of pure water to prepare a solution with a zirconium ion concentration of 0.3 mol / L. 2.70 g (3 mol%) of yttrium nitrate was added as a stabilizer, and 0.5 wt% of anhydrous ethanol was added as a dispersant. NH3·H2O was added dropwise at a rate of 80 mL / min until the pH was adjusted to 9 and the mixture was slurried for 1 h. After washing off the chloride ions with deionized water, the powder was dried and calcined at 900 °C with a heating rate of 3 °C / min and a holding time of 4 h. Subsequently, the powder was ball-milled for 0.5 h to obtain zirconium oxide ceramic powder.

[0132] The zirconia pre-sintered body of Example 14 was obtained by processing in the same manner as in Example 1. The zirconia pre-sintered body was sintered at 1350°C to achieve a density of 99.2%.

[0133] Method Example 15

[0134] Zirconia powder was prepared by alkoxide hydrolysis: 54.8 g of zirconium isopropoxide was dissolved in 1 L of pure water to prepare a solution with a zirconium ion concentration of 0.3 mol / L. 2.70 g (3 mol%) of yttrium nitrate was added as a stabilizer. 300 ml of ammonia solution was added to 500 ml of isopropanol to obtain a hydrolysate. The hydrolysate was directly mixed with the zirconium isopropoxide solution and stirred for 30 min to obtain a precursor gel. The obtained product was dried and calcined at 1000 °C at a heating rate of 3 °C / min for 4 h. Subsequently, it was ball-milled for 0.5 h to obtain zirconium oxide ceramic powder.

[0135] The zirconia pre-sintered body of Example 14 was obtained by processing in the same manner as in Example 1. The zirconia pre-sintered body was sintered at 1400°C to achieve a density of 99.4%.

[0136] Method Comparison Example 1

[0137] This comparative example is basically the same as Example 1, except that 178.13g of zirconium oxychloride was dissolved in 1L of pure water to prepare a solution with a zirconium ion concentration of 1.0mol / L and the calcination temperature was lowered to 900℃. In the same manner as Example 1, the zirconium oxide ceramic powder and the zirconium oxide pre-sintered body of Comparative Example 1 were obtained. The zirconium oxide pre-sintered body was not dense when sintered at 1400℃, and the relative sintering density was 98.7%.

[0138] Method Comparison Example 2

[0139] This comparative example is basically the same as the method example 1, except that the pressure was replaced with 0.1 MPa, the reaction temperature was replaced with 150 °C and the reaction time was replaced with 30 h. In the same manner as in example 1, the zirconia ceramic powder and zirconia pre-sintered body of comparative example 2 were obtained. The zirconia pre-sintered body was not dense when sintered at 1400 °C and the relative sintering density was 97.3%.

[0140] Method Comparison Example 3

[0141] This comparative example is basically the same as the method example 1, except that the calcination temperature was replaced with 1200℃. Zirconia ceramic powder of comparative example 3 was obtained in the same manner as in example 1. This zirconia ceramic powder could not be dry pressed, so no zirconia pre-calcined body was obtained.

[0142] Method Comparison Example 4

[0143] This comparative example is basically the same as the method example 1, except that the dry pressing pressure is replaced with 80 MPa and the pre-firing temperature is replaced with 700 °C. The zirconia ceramic powder and zirconia pre-fired body of comparative example 4 were obtained in the same manner as in example 1. The zirconia pre-fired body was not dense when sintered at 1400 °C and the relative sintering density was 95.9%.

[0144] Method Comparison Example 5

[0145] This comparative example is essentially the same as Example 1, except that the zirconium ion concentration in this comparative example is 1 mol / L. Zirconia ceramic powder and zirconia pre-sintered body of Comparative Example 5 were obtained in the same manner as in Example 1. This zirconia pre-sintered body was not densely sintered at 1400°C, and had a relative sintering density of 97.9%.

[0146] Method Comparison Example 6

[0147] This comparative example is essentially the same as Example 1, except that the hydrothermal reaction pressure in this comparative example is 0.5 MPa. Zirconia ceramic powder and zirconia pre-sintered body of Comparative Example 5 were obtained in the same manner as in Example 1. This zirconia pre-sintered body was not densely sintered at 1400°C, and had a relative sintering density of 98.6%.

[0148] Method Comparison Example 7

[0149] This comparative example is essentially the same as Example 1, except that the hydrothermal reaction temperature in this comparative example is 150°C. Zirconia ceramic powder and zirconia pre-sintered body of Comparative Example 5 were obtained in the same manner as in Example 1. This zirconia pre-sintered body was not densely sintered at 1400°C, and had a relative sintering density of 97.2%.

[0150] Method Comparison Example 8

[0151] This comparative example is basically the same as Example 1, except that the hydrothermal reaction time in this comparative example is 8 hours. Zirconia ceramic powder and zirconia pre-sintered body of Comparative Example 8 were obtained in the same manner as in Example 1. The zirconia pre-sintered body was not densely sintered and absorbed water during the density test, so the density could not be obtained.

[0152] Method Comparison Example 9

[0153] This comparative example is basically the same as Example 10, except that ball milling and dispersion were performed for 7 hours in this comparative example. Zirconia ceramic powder and zirconia pre-sintered body of Comparative Example 9 were obtained in the same manner as in Example 1. The zirconia pre-sintered body was not dense when sintered at 1400°C, and had a relative sintering density of 98.5%.

[0154] Method Comparative Example 10

[0155] Using Example 1 in CN202180007063.8 as a comparative example, the specific operation is as follows: 213g of 25% sodium sulfate aqueous solution and 450g of zirconium oxychloride aqueous solution (acid concentration: 1N) converted to ZrO2 were heated to 95°C respectively (step 1).

[0156] Next, in order to make the SO42- / ZrO2 mass ratio of the mixture 0.50, the heated aqueous solution is brought into contact with each other for 2 minutes (step 2).

[0157] Next, the obtained reaction solution containing alkaline zirconium sulfate is kept at 95°C and aged for 4 hours to obtain alkaline zirconium sulfate (step 3).

[0158] Next, after cooling the matured solution to room temperature, add 10% by mass of yttrium chloride aqueous solution to make the Y2O3 content 3 mol%, and mix evenly (step 4).

[0159] Next, 25% sodium hydroxide aqueous solution is added to the resulting mixed solution to neutralize it to a pH of 13 or higher, causing it to precipitate hydroxide (step 5).

[0160] The precipitate of hydroxide obtained by filtration is thoroughly washed with water and dried at 105°C for 24 hours. The dried hydroxide is then heat-treated in the atmosphere at 960°C (firing temperature) for 2 hours to obtain unground zirconia powder (yttrium oxide stabilized zirconia powder) (step 6).

[0161] To the obtained unground yttrium-stabilized zirconia powder, 0.25% by mass of alumina powder with an average primary particle size of 0.1 μm was added, and the mixture was ground and mixed in a wet ball mill with water as the dispersion medium for 40 hours. Zirconia beads were used in the grinding process. The resulting zirconia slurry was dried at 110°C to obtain zirconia powder of Comparative Example 10. This zirconia pre-sintered body was sintered and densified at 1200°C, achieving a relative sintering density of 99.1%.

[0162] In summary, this disclosure provides a zirconia ceramic powder with a specific surface area of ​​10–32 m². 2 / g, with an average particle size D50 of 0.1–0.3 μm and an average particle size D90 of 0.2–0.5 μm. The peak intensity ratio of the 220 / 200 crystal planes of the zirconia ceramic powder, determined by powder X-ray diffraction, was 1.2–2.5. The average crystallite diameter of the zirconia ceramic powder, obtained from the (-111) plane peaks of the zirconia ceramic powder grains by X-ray diffraction, was [missing value]. The particle size (D50) of zirconia ceramic powder affects its specific surface area and sintering activity, thus influencing the solid-state diffusion rate and the interaction between sintered particles during sintering. Smaller particle sizes result in larger specific surface areas, increasing the contact area between powder particles, improving the solid-state diffusion rate, and enhancing sintering activity, leading to relatively lower sintering temperatures. Simultaneously, the particle size (D90) needs to be controlled; excessively large D90 indicates the presence of numerous large particles, causing molding defects and affecting sintering performance, strength, and permeability. A peak intensity ratio of 220° crystal facets to 200° crystal facets controlled within the range of 1.2-2.5 ensures that the molded body does not easily disintegrate and exhibits excellent sintered body strength. The average crystallite diameter is within... This ensures minimal porosity defects in the grains, effectively preventing any impact on the strength and permeability of the sintered body, thus achieving low-temperature sintering. This disclosure controls the specific surface area, particle size, peak intensity ratio of the 220 crystal plane to the 200 crystal plane, and average crystallite diameter of the zirconia ceramic powder. Zirconia ceramic powder meeting these numerical ranges exhibits specific crystal orientation, enabling low-temperature sintering without the addition of sintering aids, and yielding sintered bodies with high strength and high sintering density.

[0163] The above are merely optional embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure. Industrial applicability

[0164] This disclosure provides a zirconia ceramic powder, its preparation method, and a zirconia sintered body. By controlling the specific surface area, particle size, peak intensity ratio of the 220 crystal plane to the 200 crystal plane, and average crystallite diameter of the zirconia ceramic powder, a zirconia ceramic powder with high sintering density that can be sintered at low temperature under normal pressure can be obtained. Since the zirconia ceramic powder is a nanoparticle, its scattering cross section is small, scattering at the grain boundaries is reduced, and its tetragonality is smaller, resulting in lower birefringence. The light transmittance of the obtained zirconia ceramic is improved, while also possessing high strength.

Claims

1. A zirconia ceramic powder, characterized in that, It comprises a solid solution formed by zirconium oxide and a stabilizer, wherein the specific surface area of ​​the zirconium oxide ceramic powder is 10–32 m². 2 / g, with an average particle size D50 of 0.1–0.3 μm and an average particle size D90 of 0.2–0.5 μm. The peak intensity ratio of the 220 / 200 crystal planes of the zirconia ceramic powder, determined by powder X-ray diffraction, is 1.2–2.

5. The average crystallite diameter of the zirconia ceramic powder, obtained from the (-111) plane peak of the zirconia ceramic powder grains by X-ray diffraction, is [missing value].

2. The zirconia ceramic powder according to claim 1, characterized in that, in, The 2θ angle corresponding to the 220 crystal plane is 49.5° to 50.5°, the 2θ angle corresponding to the 200 crystal plane is 29.5° to 30.5°, and the 2θ angle corresponding to the (-111) crystal plane is 31° to 32°.

3. The zirconia ceramic powder according to any one of claims 1-2, characterized in that, The sintering initiation point of the zirconia ceramic powder is below 1300℃, and the sintering initiation point is obtained based on the DIL test.

4. The zirconia ceramic powder according to any one of claims 1-3, characterized in that, The stabilizer includes at least one of Y source, Ca source, Mg source and Er source.

5. The zirconia ceramic powder according to claim 4, characterized in that, The Y source includes one or more of yttrium oxide, yttrium nitrate, yttrium chloride, and yttrium sulfate; And / or, the content of the Y source relative to the zirconia ceramic powder is 1.5–5 mol%.

6. The zirconia ceramic powder according to any one of claims 4-5, characterized in that, The Ca source includes one or more of calcium oxide, calcium carbonate, and calcium chloride; And / or, the content of the Ca source relative to the zirconia ceramic powder is 4-8 mol%.

7. The zirconia ceramic powder according to any one of claims 4-6, characterized in that, The Mg source includes one or more of magnesium oxide, magnesium chloride, and magnesium sulfate; And / or, the content of the Mg source relative to the zirconia ceramic powder is 6-13 mol%.

8. The zirconia ceramic powder according to any one of claims 4-7, characterized in that, The Er source is erbium oxide; And / or, the Er source content relative to the total zirconium oxide powder is 3-5 mol%.

9. The zirconia ceramic powder according to any one of claims 1-8, characterized in that, The zirconia ceramic powder further includes at least one of a first dopant (0.005-1 wt%) that produces a coloring effect and a second dopant (0.005-1 wt%) that improves toughness and low-temperature aging resistance.

10. The zirconia ceramic powder according to claim 9, characterized in that, The first dopant includes at least one of Fe, Er, Mn, Co, Cr, Tb, Pr, Nd, Eu and Ti.

11. The zirconia ceramic powder according to any one of claims 9-10, characterized in that, The second dopant is Al.

12. The zirconia ceramic powder according to claim 11, characterized in that, The Al includes one or more of aluminum oxide, aluminum chloride, and aluminum nitrate.

13. A method for preparing zirconia ceramic powder as described in any one of claims 1-12, characterized in that, It includes: S1. Prepare a solution of soluble zirconium salt with a zirconium ion concentration of 0.3-0.7 mol / L, and perform hydrothermal reaction for 12-50 h under the conditions of pressure of 0.2-0.35 MPa and temperature of 120-140℃. Add a stabilizer to the product to obtain the reaction solution. S2. The reaction solution is dried and then calcined at a temperature of 950-1150℃, a heating rate of 2.5-6℃ / min, and a holding time of 1-5h to obtain calcined powder. S3. The calcined powder is ball-milled to obtain zirconia ceramic powder for 0.5-6 hours.

14. The method for preparing zirconia ceramic powder according to claim 13, characterized in that, The zirconium salt includes at least one of zirconium oxychloride, zirconium acetate, and zirconium carbonate.

15. A zirconia sintered body, characterized in that, It includes zirconia ceramic powder prepared by the method of preparing zirconia ceramic powder as described in claims 1-12 or as described in any one of claims 13-14, which is then subjected to frequent pressing and sintering.

16. The zirconia sintered body according to claim 15, characterized in that, The atmospheric pressure sintering includes sequentially performing dry pressing, isostatic pressing, pre-sintering, and sintering.

17. The zirconia sintered body according to claim 16, characterized in that, The dry pressing pressure for the dry pressing molding is 120-300MPa, and the dry pressing time is 30-180s; And / or, the isostatic pressing pressure of the isostatic pressing molding is 150-350MPa, and the isostatic pressing time is 5-20min; And / or, the pre-sintering temperature is 800-1100℃, and the pre-sintering time is 15h-60h; And / or, the sintering temperature is 1150℃-1400℃, and the sintering time is 30min-10h.

18. The zirconia sintered body according to any one of claims 15-17, characterized in that, The sintered density of the zirconia sintered body is ≥99%, the strength is 700-1300 MPa, and the permeability is 38-44%.

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