Zirconia-based composite powder, zirconia pre-sintered body and preparation method therefor, and zirconia sintered body and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of composite materials, and provides zirconia-based composite powder, a zirconia pre-sintered body and a preparation method therefor, and a zirconia sintered body and a preparation method therefor and the use thereof. The zirconia-based composite powder provided comprises a yttrium oxide powder, an aluminum oxide powder and a zirconia powder; the specific surface area of the zirconia-based composite powder is 7.5- 9 g / m 2; and the particle size D50 of the zirconia-based composite powder is 180-250 nm. When the zirconia-based composite powder provided is used to prepare a zirconia sintered body, the zirconia sintered body with high strength and density can be obtained simply by sintering the zirconia pre-sintered body for ≤ 30 min, which greatly improves the production efficiency.

Description

Zirconia-based composite powder, zirconia calcined body and preparation method thereof, zirconia sintered body and preparation method and application thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on November 1, 2023, with application number CN202311447363.5 and invention name “A zirconia-based composite powder, a zirconia pre-calcined body and its preparation method, a zirconia sintered body and its preparation method and application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of composite materials, and in particular to a zirconia-based composite powder, a zirconia calcined body and a preparation method thereof, a zirconia sintered body and a preparation method and application thereof. Background Art

[0003] Zirconia ceramics, with their excellent biocompatibility and mechanical properties, have become a key focus in dental ceramic development. In recent years, ceramics such as zirconia have been used to replace metals in dental restorations (covers, crowns, and dentures) for both aesthetic and safety reasons.

[0004] When using traditional zirconia powder to prepare zirconia sintered bodies, it is usually necessary to sinter the zirconia pre-calcined body for more than 4 hours to obtain a zirconia sintered body with high strength and density. The production efficiency is low, which limits its development.

[0005] Summary of the Invention

[0006] The purpose of the present application is to provide a zirconia-based composite powder, a zirconia pre-calcined body and a preparation method thereof, a zirconia sintered body and a preparation method and application thereof. The zirconia-based composite powder provided in the present application is used to prepare a zirconia sintered body. It is only necessary to sinter the zirconia pre-calcined body for a time of ≤30 minutes to obtain a zirconia sintered body with high strength and density, thereby greatly improving production efficiency.

[0007] In order to achieve the above-mentioned invention objectives, this application provides the following technical solutions:

[0008] The present application provides a zirconium oxide-based composite powder, comprising yttrium oxide powder, aluminum oxide powder and zirconium oxide powder; the specific surface area of ​​the zirconium oxide-based composite powder is 7.5 to 9 g / m 2 ; The particle size D50 of the zirconium oxide-based composite powder is 180 to 250 nm.

[0009] Preferably, based on the total weight of the zirconium oxide-based composite powder, the content of the yttrium oxide powder is 7.5-9 wt%, and the content of the aluminum oxide powder is 0.02-0.05 wt%.

[0010] Preferably, the zirconia-based composite powder further includes a colorant; based on the total weight of the zirconia-based composite powder, the content of the colorant is ≤1.5wt%; the colorant includes one or more of Fe2O3, Er2O3, Co3O4, MnO, NiO and Cr2O3.

[0011] The present application provides a zirconia calcined body, which is prepared from the zirconia-based composite powder described in the above technical solution; the relative density of the zirconia calcined body is 50-55%, and the flexural strength of the zirconia calcined body is 10-50 MPa.

[0012] The present application provides a method for preparing a zirconia calcined body according to the above technical solution, comprising the following steps:

[0013] The zirconium oxide-based composite powder is sequentially dry pressed, cold isostatically pressed and pre-sintered to obtain a zirconium oxide pre-sintered body.

[0014] The present application provides a method for preparing a zirconia sintered body, comprising the following steps:

[0015] The zirconium oxide calcined body described in the above technical solution or the zirconium oxide calcined body prepared by the preparation method described in the above technical solution is processed, formed and sintered in sequence to obtain a zirconium oxide sintered body; the sintering time is ≤30 minutes.

[0016] Preferably, the sintering temperature is 1500-1580°C.

[0017] The present application provides a zirconia sintered body prepared by the preparation method described in the above technical solution.

[0018] Preferably, the flexural strength of the zirconia sintered body is ≥800 MPa; the density of the zirconia sintered body is ≥6.05 g / cm 3 .

[0019] The present application provides the use of the zirconium oxide sintered body described in the above technical solution in the preparation of dental materials.

[0020] The present application provides a zirconium oxide-based composite powder, comprising yttrium oxide powder, aluminum oxide powder and zirconium oxide powder; the specific surface area of ​​the zirconium oxide-based composite powder is 7.5 to 9 g / m 2; The particle size D50 of the zirconia-based composite powder is 180-250nm. Compared with traditional powders, the zirconia-based composite powder provided by the present application has a lower specific surface area and a larger particle size, which can separate the interface diffusion in the low-temperature section of sintering and the grain boundary diffusion in the high-temperature section, thereby reducing closed pores; at the same time, the total surface area of ​​the grain boundary in the high-temperature section of sintering is reduced, which promotes the grain boundary diffusion mass transfer process and reduces the energy required for grain growth. The zirconia-based composite powder provided by the present application is used to prepare a zirconia sintered body, and a sintering time of only ≤30min is required to obtain a zirconia sintered body with high strength and density, thereby greatly improving production efficiency. DETAILED DESCRIPTION

[0021] The present application provides a zirconium oxide-based composite powder, comprising yttrium oxide powder, aluminum oxide powder and zirconium oxide powder; the specific surface area of ​​the zirconium oxide-based composite powder is 7.5 to 9 g / m 2 ; The particle size D50 of the zirconium oxide-based composite powder is 180 to 250 nm.

[0022] The zirconia-based composite powder provided herein includes yttrium oxide (Y2O3) powder. In the present application, the content of the yttrium oxide powder is preferably 7.5-9 wt%, more preferably 7.5-8.5 wt%, based on the total weight of the zirconia-based composite powder.

[0023] The zirconia-based composite powder provided herein comprises aluminum oxide (Al2O3) powder. In the present application, the content of the aluminum oxide powder is preferably 0.02-0.05 wt%, more preferably 0.03-0.04 wt%, based on the total weight of the zirconia-based composite powder.

[0024] In the present application, the zirconia-based composite powder preferably further comprises a colorant. In the present application, the colorant preferably comprises one or more of Fe2O3, Er2O3, Co3O4, MnO, NiO, and Cr2O3. In the present application, the content of the colorant is preferably ≤1.5 wt%, more preferably 0.3-1 wt%, based on the total weight of the zirconia-based composite powder.

[0025] In the present application, the zirconia-based composite powder includes a balance of zirconia powder.

[0026] In the present application, the specific surface area (BET) of the zirconium oxide-based composite powder is 7.5 to 9 g / m 2 , preferably 7.5 to 8.5 g / m 2 The particle size D50 of the zirconium oxide-based composite powder is 180 to 250 nm, preferably 220 to 250 nm.

[0027] In the present application, the method for preparing the zirconia-based composite powder preferably includes ball-milling yttrium oxide powder, aluminum oxide powder, and zirconium oxide powder. In the present application, when the zirconia-based composite powder includes a colorant, the yttrium oxide powder, aluminum oxide powder, zirconium oxide powder, and colorant are preferably ball-milled. In the present application, the rotation speed of the ball milling is preferably 500-1000 rpm, more preferably 800-900 rpm; the ball milling time is preferably 1-3 hours, more preferably 2 hours. In the present application, the grinding media used in the ball milling are preferably zirconium oxide balls; the ball-to-material ratio of the ball milling is preferably 3-8:1, more preferably 5-7:1.

[0028] The present application provides a zirconia calcined body, which is prepared from the zirconia-based composite powder described in the above technical solution; the relative density of the zirconia calcined body is 50-55%, preferably 52-55%, and more preferably 53-54%; the flexural strength of the zirconia calcined body is 10-50 MPa, preferably 15-46 MPa, and more preferably 32-36 MPa.

[0029] The present application provides a method for preparing a zirconia calcined body according to the above technical solution, comprising the following steps:

[0030] The zirconium oxide-based composite powder is sequentially dry pressed, cold isostatically pressed and pre-sintered to obtain a zirconium oxide pre-sintered body.

[0031] In the present application, the dry pressing pressure is preferably 2-10 MPa, more preferably 3-7 MPa, and further preferably 4-5 MPa; the dry pressing time is preferably 5-20 s, and more preferably 7-13 s. In the present application, the cold isostatic pressing pressure is preferably 150-300 MPa, more preferably 200-250 MPa, and further preferably 220-240 MPa; the cold isostatic pressing time is preferably 30-200 s, more preferably 50-180 s, and further preferably 60-120 s. In the present application, the pre-sintering temperature is preferably 900-1100°C, more preferably 950-1070°C, and further preferably 990-1036°C; the pre-sintering time is preferably 30-180 min, more preferably 60-120 min, and further preferably 80-100 min.

[0032] The present application provides a method for preparing a zirconia sintered body, comprising the following steps:

[0033] The zirconium oxide calcined body described in the above technical solution or the zirconium oxide calcined body prepared by the preparation method described in the above technical solution is processed, formed and sintered in sequence to obtain a zirconium oxide sintered body; the sintering time is ≤30 minutes.

[0034] In the present application, the processing and forming method is preferably engraving and forming with a CAM device.

[0035] In the present application, the sintering time is ≤30 min, preferably 15 to 25 min.

[0036] In the present application, the sintering temperature is preferably 1500-1580°C, more preferably 1530-1560°C. In the present application, the sintering procedure preferably includes: first heating from room temperature to 1100-1200°C at 200-300°C / min, then heating to 1500-1580°C at 20-60°C / min, holding for 2-15 minutes, and then cooling to 900°C at 200°C / min. In a specific embodiment of the present application, the sintering procedure is: first heating from room temperature to 1200°C at 200-250°C / min, then heating to 1520-1570°C at 30-50°C / min, holding for 3-10 minutes, and then cooling to 900°C at 200°C / min.

[0037] The present application provides a zirconia sintered body prepared by the preparation method described in the above technical solution. In the present application, the flexural strength of the zirconia sintered body is preferably ≥800 MPa, more preferably 986-1053 MPa, and even more preferably 996-1023 MPa; the density of the zirconia sintered body is preferably ≥6.05 g / cm 3 , more preferably 6.059 to 6.068 g / cm 3 , more preferably 6.063 to 6.067 g / cm 3 .

[0038] The present application provides the use of the zirconium oxide sintered body described in the above technical solution in the preparation of dental materials.

[0039] The following will be combined with the embodiments of this application to clearly and completely describe the technical solutions in this application. Obviously, the embodiments described are only some of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] Example 1

[0041] 75g of yttrium oxide powder, 0.5g of aluminum oxide powder, 909.5g of zirconium oxide powder and 15g of colorant (components are 2.5g of Fe2O3, 11g of Er2O3, 0.2g of Co3O4, 0.5g of MnO, 0.5g of NiO and 0.3g of Cr2O3) are ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed is 900rpm; the ball milling time is 3h; the grinding body used in the ball milling is zirconium oxide ball; and the ball-to-material ratio of the ball milling is 5:1.

[0042] The specific surface area (BET) of the zirconia-based composite powder prepared in this example is 9 g / m 2 ; Particle size D50 is 220nm.

[0043] Example 2

[0044] 85g of yttrium oxide powder, 0.2g of aluminum oxide powder, 909.8g of zirconium oxide powder and 5g of colorant (composed of 0.5g of Fe2O3, 4.45g of Er2O3, and 0.05g of Co3O4) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 900rpm; the ball milling time was 1h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0045] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this example is 7.5 g / m 2 ; Particle size D50 is 250nm.

[0046] Example 3

[0047] 90g of yttrium oxide powder, 0.3g of aluminum oxide powder, 906.7g of zirconium oxide powder and 3g of colorant (composed of 0.3g of Fe2O3, 2.65g of Er2O3, and 0.05g of MnO) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 900rpm; the ball milling time was 2h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0048] The specific surface area (BET) of the zirconia-based composite powder prepared in this example is 8.2 g / m 2 ; Particle size D50 is 237nm.

[0049] Comparative Example 1

[0050] 95g of yttrium oxide powder, 0.15g of aluminum oxide powder, 902.85g of zirconium oxide powder and 2g of colorant (composed of 0.3g of Fe2O3, 1.68g of Er2O3, and 0.02g of MnO) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 800rpm; the ball milling time was 1h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0051] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this comparative example is 7.3 g / m 2 ; Particle size D50 is 253nm.

[0052] Comparative Example 2

[0053] 85g of yttrium oxide powder, 0.55g of aluminum oxide powder, 912.45g of zirconium oxide powder and 2g of colorant (0.3g of Fe2O3, 1.68g of Er2O3, 0.02g of MnO) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 1000rpm; the ball milling time was 3h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0054] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this comparative example is 10 g / m 2 ; Particle size D50 is 178nm.

[0055] Comparative Example 3

[0056] 90g of yttrium oxide powder, 1g of aluminum oxide powder, 906g of zirconium oxide powder and 3g of colorant (Fe2O30.4g, Er2O32.56g, MnO0.04g) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 1000rpm; the ball milling time was 4h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0057] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this comparative example is 11 g / m 2 ; Particle size D50 is 152nm.

[0058] Comparative Example 4

[0059] 95g of yttrium oxide powder, 0.1g of aluminum oxide powder, 901.9g of zirconium oxide powder and 3g of colorant (0.4g of Fe2O3, 2.56g of Er2O3, 0.04g of MnO) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 600rpm; the ball milling time was 1h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0060] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this comparative example is 6.2 g / m 2 ; Particle size D50 is 447nm.

[0061] Comparative Example 5

[0062] 57.4 g of yttrium oxide powder, 0.06 g of aluminum oxide powder, 939.54 g of zirconium oxide powder and 3 g of colorant (0.4 g of Fe2O3, 2.56 g of Er2O3, and 0.04 g of MnO) were ball-milled to obtain a zirconium oxide-based composite powder; the ball milling speed was 1000 rpm; the ball milling time was 3.5 h; the grinding body used in the ball milling was zirconium oxide balls; and the ball-to-material ratio of the ball milling was 5:1.

[0063] The specific surface area (BET) of the zirconium oxide-based composite powder prepared in this comparative example is 10.4 g / m 2 ; Particle size D50 is 168nm.

[0064] Application Example 1

[0065] The zirconia-based composite powder prepared in Example 1 was dry pressed, cold isostatically pressed and pre-sintered in sequence to obtain a zirconia pre-calcined body; the dry pressing pressure was 4 MPa; the dry pressing time was 7 s; the cold isostatic pressing pressure was 240 MPa; the cold isostatic pressing time was 60 s; the pre-sintering temperature was 1036°C; the pre-sintering time was 80 min; the relative density and flexural strength of the zirconia pre-calcined body are shown in Table 1.

[0066] The zirconia pre-calcined body is processed, formed and sintered in sequence to obtain a zirconia sintered body; the sintering procedure is as follows: first, the temperature is increased from room temperature to 1200°C at 200°C / min, then the temperature is increased to 1550°C at 30°C / min, kept at 1550°C for 5 minutes, and then cooled to 900°C at 200°C / min; the total sintering time is 25.8 minutes.

[0067] The flexural strength and density of the zirconia sintered body are shown in Table 1.

[0068] Application Example 2

[0069] The zirconium oxide-based composite powder prepared in Example 2 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0070] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0071] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0072] Application Example 3

[0073] The zirconium oxide-based composite powder prepared in Example 3 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0074] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0075] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0076] Application Example 4

[0077] The zirconia-based composite powder prepared in Example 2 was dry pressed, cold isostatically pressed and pre-sintered in sequence to obtain a zirconia pre-calcined body; the dry pressing pressure was 7 MPa; the dry pressing time was 7 s; the cold isostatic pressing pressure was 240 MPa; the cold isostatic pressing time was 180 s; the pre-sintering temperature was 990°C; the pre-sintering time was 80 min; the relative density and flexural strength of the zirconia pre-calcined body are shown in Table 1.

[0078] The zirconia calcined body is processed, shaped and sintered in sequence to obtain a zirconia sintered body; the sintering procedure is the same as that of Application Example 1.

[0079] The flexural strength and density of the zirconia sintered body are shown in Table 1.

[0080] Application Example 5

[0081] The zirconium oxide-based composite powder prepared in Example 2 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body;

[0082] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1.

[0083] The zirconia pre-calcined body is processed, formed and sintered in sequence to obtain a zirconia sintered body; the sintering procedure is as follows: first, the temperature is increased from room temperature to 1200°C at 300°C / min, then the temperature is increased to 1520°C at 50°C / min, kept at 1520°C for 10 minutes, and then cooled to 900°C at 200°C / min; the total sintering time is 23.4 minutes.

[0084] The flexural strength and density of the zirconia sintered body are shown in Table 1.

[0085] Comparative Application Example 1

[0086] The zirconium oxide-based composite powder prepared in Comparative Example 1 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0087] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0088] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0089] Comparative Application Example 2

[0090] The zirconium oxide-based composite powder prepared in Comparative Example 2 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0091] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0092] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0093] Comparative Application Example 3

[0094] The zirconium oxide-based composite powder prepared in Comparative Example 3 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0095] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0096] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0097] Comparative Application Example 4

[0098] The zirconium oxide-based composite powder prepared in Comparative Example 4 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0099] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0100] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0101] Comparative Application Example 5

[0102] The zirconium oxide-based composite powder prepared in Comparative Example 5 was prepared according to the method of Application Example 1 to obtain a zirconium oxide calcined body and a zirconium oxide sintered body;

[0103] The relative density and flexural strength of the prepared zirconia calcined body are shown in Table 1;

[0104] The flexural strength and density of the prepared zirconia sintered body are shown in Table 1.

[0105] Table 1 Performance test results of application examples and comparative application examples

[0106] In Table 1, the relative density of the zirconia calcined body is calculated as the actual measured density of the zirconia calcined body / theoretical density; the actual measured density of the zirconia calcined body is calculated as ρ=m / V; where ρ is the actual measured density of the zirconia calcined body, in g / cm 3 ; m is the mass of the zirconia calcined body, in g; V is the volume of the zirconia calcined body, in cm 3 Zirconia pre-calcined and sintered bodies were tested for flexural strength using a three-point bending test in accordance with the standard "GB 30367-2013 Dental Ceramics." Strength bars with dimensions of 4±0.2mm width, 3±0.2mm thickness, 0.09-0.15mm chamfer, and 30mm span were prepared. The three-point bending test was performed, and the mean and standard deviation of the flexural strength were recorded. The density of the sintered zirconia bodies was determined using the Archimedean displacement method.

[0107] It can be seen from Table 1 that when the BET and powder particle size D50 of the prepared zirconia-based composite powder are not within the range specified in this application, the relative density and strength of the formed zirconia calcined body will be affected. When the BET is too small and the D50 is too large, the relative density and strength of the zirconia calcined body are low; when the BET is too large and the D50 is too small, the relative density and strength of the zirconia calcined body are higher.

[0108] From the density and strength results of the zirconia sintered bodies of Comparative Application Examples 1 to 5 in Table 1, it can be seen that when the BET and powder particle size D50 of the zirconia-based composite powder are not within the range specified in this application, the zirconia pre-calcined body at this time cannot meet the density and strength standards of the zirconia sintered body after rapid sintering.

[0109] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A zirconium oxide-based composite powder, characterized in that: The invention comprises yttrium oxide powder, aluminum oxide powder and zirconium oxide powder; the specific surface area of ​​the zirconium oxide-based composite powder is 7.5 to 9 g / m 2 ; The particle size D50 of the zirconium oxide-based composite powder is 180 to 250 nm.

2. The zirconium oxide-based composite powder according to claim 1, characterized in that: Based on the total weight of the zirconium oxide-based composite powder, the content of the yttrium oxide powder is 7.5-9wt%, and the content of the aluminum oxide powder is 0.02-0.05wt%.

3. The zirconium oxide-based composite powder according to claim 1, characterized in that: The zirconia-based composite powder also includes a colorant; based on the total weight of the zirconia-based composite powder, the content of the colorant is ≤1.5wt%; the colorant includes one or more of Fe2O3, Er2O3, Co3O4, MnO, NiO and Cr2O3.

4. The method for preparing the zirconium oxide-based composite powder according to any one of claims 1 to 3, comprising the following steps: Yttria powder, aluminum oxide powder and zirconium oxide powder are ball-milled and mixed to obtain zirconium oxide-based composite powder.

5. The preparation method according to claim 4, characterized in that: The rotation speed of the ball milling mixing is 500-1000 rpm; the time of the ball milling mixing is 1-3 hours.

6. A zirconia calcined body, characterized in that: The zirconia-based composite powder is prepared by the zirconia-based composite powder according to any one of claims 1 to 3 or the zirconia-based composite powder prepared by the preparation method according to any one of claims 4 to 5; the relative density of the zirconia calcined body is 50 to 55%, and the flexural strength of the zirconia calcined body is 10 to 50 MPa.

7. The method for preparing the calcined zirconium oxide body according to claim 6, comprising the following steps: The zirconium oxide-based composite powder is sequentially dry pressed, cold isostatically pressed and pre-sintered to obtain a zirconium oxide pre-sintered body.

8. The preparation method according to claim 7, characterized in that: The dry pressing pressure is 2-10 MPa; the dry pressing time is 5-20 s.

9. The preparation method according to claim 7, characterized in that: The pressure of the cold isostatic pressing is 150-300 MPa; the time of the cold isostatic pressing is 30-200 s.

10. The preparation method according to claim 7, characterized in that: The pre-sintering temperature is 900-1100° C.; the pre-sintering time is 30-180 minutes.

11. A method for preparing a zirconia sintered body, comprising the following steps: The zirconium oxide calcined body according to claim 6 or the zirconium oxide calcined body prepared by the preparation method according to any one of claims 7 to 10 is processed, formed and sintered in sequence to obtain a zirconium oxide sintered body; the sintering time is ≤30 minutes.

12. The preparation method according to claim 11, characterized in that: The sintering temperature is 1500-1580°C.

13. The preparation method according to claim 11 or 12, characterized in that: The sintering procedure includes: firstly heating from room temperature to 1100-1200°C at 200-300°C / min, then heating to 1500-1580°C at 20-60°C / min, keeping the temperature for 2-15 minutes, and then cooling to 900°C at 200°C / min.

14. The zirconia sintered body prepared by the preparation method according to any one of claims 11 to 13, wherein the flexural strength of the zirconia sintered body is ≥ 800 MPa; and the density of the zirconia sintered body is ≥ 6.05 g / cm 3 .

15. Use of the zirconium oxide sintered body according to claim 14 in preparing dental materials.

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