Preparation method and application of zirconia ceramics

Abstract

The invention discloses a preparation method and application of zirconia ceramics, and relates to the technical field of zirconia ceramics. The method comprises the following steps: mixing 100nm-200nm nano-zirconia, 200nm-400nm alumina, a binder, an emulsifier, and a dispersant; using high-purity alumina grinding balls as grinding media; stirring and milling at a rotation speed of 700-1000r / min for 4-8h; and then grinding at a sand mill rotation speed of 1500-2000r / min for 1-2h to obtain a mixed slurry; spray granulating the mixed slurry; and depositing Fe3Al on the surface of a composite ATZ powder by magnetron sputtering after mixing and granulating the components of the zirconia ceramic. This ensures uniform dispersion and bonding strength of the composite powder. At the same time, since Fe3Al has a thermal expansion coefficient similar to that of zirconia, the low-temperature thermal shock resistance of the zirconia ceramic is improved without sacrificing its fracture toughness, strength, and hardness, thereby ensuring the stability of the zirconia ceramic bearing. Compared with the traditional mixed powder making process, this method significantly improves the thermal shock resistance and strength of the ceramic.

Description

Technical Field

[0001] The present invention relates to the technical field of zirconia ceramics, and in particular to a preparation method and application of zirconia ceramics. Background Art

[0002] Zirconia ceramics have excellent properties such as wear resistance, self-lubrication, chemical corrosion resistance, electrical insulation, high strength, high hardness and high toughness, and are widely used in the fields of medicine, aerospace, chemical industry, electronics, etc. Zirconia is usually mainly yttria-stabilized tetragonal zirconia. Depending on the yttria content, there are partially stabilized zirconia ceramics, fully stabilized zirconia ceramics, and polycrystalline stabilized zirconia ceramics. However, fully stabilized zirconia ceramics and partially stabilized zirconia ceramics have poor mechanical properties and are generally not used as structural ceramics. Polycrystalline stabilized zirconia, on the other hand, has better mechanical properties and is often used as structural ceramics. However, polycrystalline stabilized zirconia has problems such as low-temperature aging, stress-induced aging, and environmentally induced aging. The reason is that under the above conditions, the stable tetragonal zirconia gradually transforms into monoclinic zirconia, at which time the volume expands, inducing microcracks. When the cracks expand to a certain extent, the material fails. Therefore, a method for preparing zirconia ceramics is needed to solve the above problems. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method and application of zirconia ceramics to solve the problems existing in the prior art mentioned in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The method for preparing zirconia ceramics comprises the following steps:

[0006] S1: Mix 100nm-200nm nano-zirconia, 200nm-400nm alumina, a binder, an emulsifier, and a dispersant, use high-purity alumina grinding balls as grinding media, stir and grind at a speed of 700-1000r / min for 4-8h, and then grind at a sand mill speed of 1500-2000r / min for 1-2h to obtain a mixed slurry;

[0007] S2: spray granulating the mixed slurry to obtain uniform ATZ composite powder;

[0008] S3: Fe3Al is deposited on the surface of the composite ATZ powder by magnetron sputtering with a deposition thickness of 0.1-0.3 μm to obtain a uniform composite powder;

[0009] S4: dry-pressing the composite powder obtained in S3 to obtain a green body;

[0010] S5: Sintering the green body to obtain zirconia ceramics.

[0011] Preferably, in S1, the mass fraction of nano-zirconium oxide is 70-90 wt %, the mass fraction of the binder is 1.5-2 wt %, the mass fraction of the emulsifier is 1.0-1.5 wt %, and the mass fraction of the dispersant is 1.5 wt %.

[0012] Preferably, the diameter of the high-purity alumina grinding balls in S1 is 3-5 mm.

[0013] Preferably, the spray speed in S2 is set to 15000-20000 r / min, the inlet temperature is set to 220±5°C, and the outlet temperature is set to 110°C±10°C.

[0014] Preferably, in S4, the pressure of dry pressing is set to 200 MPa.

[0015] Preferably, in S5, the sintering heating rate of the green embryo is set to 0.5°C / min, and the sintering is carried out in a protective argon atmosphere at a temperature of 1500°C for 4 hours.

[0016] The present invention also provides an application of the zirconia ceramic, which is used in the manufacture of parts for equipment in the medical, aerospace, chemical, and electronic fields.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention mixes and granulates the various components of zirconia ceramics, and then deposits Fe3Al on the surface of the composite ATZ powder by magnetron sputtering, thereby ensuring the uniform dispersion and bonding strength of the composite powder. At the same time, since Fe3Al has a similar thermal expansion coefficient to zirconia, the low-temperature thermal shock resistance of zirconia ceramics is improved without sacrificing its fracture toughness, strength, and hardness, thereby ensuring the stability of zirconia ceramic bearings. Compared with the traditional mixed powder making process, this method significantly improves the thermal shock resistance and strength of the ceramics.

[0019] 2. The present invention enhances the wear resistance of zirconia ceramics by introducing alumina. In addition, by controlling the content and moisture content of the additive, it ensures that the powder can obtain uniform shrinkage, size and density during subsequent dry pressing or static pressing, thereby increasing the consistency and controllability of subsequent processing, making the quality and cost of the processed products very controllable. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0021] The present invention provides the following technical solutions:

[0022] Example 1

[0023] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, and 1.5 wt% D305 dispersant were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0024] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0025] S3: Fe3Al is deposited on the surface of the composite ATZ powder by magnetron sputtering with a deposition thickness of 0.1 μm to obtain a uniform composite powder;

[0026] S4: dry pressing the composite powder obtained in S3 at 200 MPa to obtain a green body;

[0027] S5: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0028] The performance test of the zirconia ceramic obtained in Example 1 showed that its strength reached 1200 MPa, and after aging at 132 ° C for 10 h at 0.2 MPa, its strength reached 1180 MPa, and the number of hot and cold shocks at 200 ° C reached 20 times, its hardness reached 1450 Hv, its density reached 99%, and its fracture toughness reached 10 MPa*m. 1 / 2 .

[0029] Example 2

[0030] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, and 1.5 wt% D305 dispersant were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0031] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0032] S3: Fe3Al is deposited on the surface of the composite ATZ powder by magnetron sputtering with a deposition thickness of 0.2 μm to obtain a uniform composite powder;

[0033] S4: dry pressing the composite powder obtained in S3 at 200 MPa to obtain a green body;

[0034] S5: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0035] The difference between Example 2 and Example 1 is that the thickness of the magnetron sputtered Fe3Al is increased to 0.2μm. The zirconia ceramics obtained in Example 2 are subjected to performance tests, and their strength reaches 1200MPa. After aging at 132°C for 10h at 0.2Mpa, the strength reaches 1150Mpa, the number of hot and cold shocks at 200°C reaches 21 times, the hardness reaches 1440Hv, the density reaches 99%, and the fracture toughness reaches 11.5Mpa*m1 / 2.

[0036] Example 3

[0037] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, and 1.5 wt% D305 dispersant were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0038] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0039] S3: Fe3Al was deposited on the surface of the composite ATZ powder by magnetron sputtering with a deposition thickness of 0.3 μm to obtain a uniform composite powder;

[0040] S4: dry pressing the composite powder obtained in S3 at 200 MPa to obtain a green body;

[0041] S5: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0042] The difference between Example 3 and Example 1 is that the thickness of the magnetron sputtered Fe3Al is increased to 0.3 μm. The performance test of the zirconia ceramic obtained in Example 3 shows that its strength reaches 1200 MPa, and after aging at 132°C for 10 h at 0.2 MPa, the strength reaches 1130 MPa, the number of hot and cold shocks at 200°C reaches 25 times, the hardness reaches 1430 Hv, the density reaches 99%, and the fracture toughness reaches 11.4 MPa*m 1 / 2 .

[0043] Comparative Example 1

[0044] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, 1.5 wt% D305 dispersant, and the same amount of Fe3Al as in Example 1 were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0045] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0046] S3: dry pressing the composite powder at 200 MPa to obtain a green body;

[0047] S4: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0048] The difference between Comparative Example 1 and Example 1 is that Fe3Al is directly mixed with the components for preparation. The zirconia ceramic obtained in Comparative Example 1 is subjected to performance testing, and its strength reaches 900 MPa. After aging at 132°C for 10 h at 0.2 MPa, the strength reaches 850 MPa, the number of hot and cold shocks at 200°C reaches 5 times, the hardness reaches 1400 Hv, the density reaches 99%, and the fracture toughness reaches 9.5 MPa*m1 / 2.

[0049] Comparative Example 2

[0050] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, 1.5 wt% D305 dispersant, and the same amount of Fe3Al as in Example 2 were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0051] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0052] S3: dry pressing the composite powder at 200 MPa to obtain a green body;

[0053] S4: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0054] The difference between Comparative Example 2 and Example 2 is that Fe3Al is directly mixed with the components for preparation. The zirconia ceramic obtained in Comparative Example 2 is subjected to performance testing, and its strength reaches 890 MPa. After aging at 132°C for 10 h at 0.2 MPa, the strength reaches 840 MPa, the number of hot and cold shocks at 200°C reaches 7 times, the hardness reaches 1400 Hv, the density reaches 99%, and the fracture toughness reaches 9.2 MPa*m1 / 2.

[0055] Comparative Example 3

[0056] S1: 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% Y-654 emulsifier, 1.5 wt% D305 dispersant, and the same amount of Fe3Al as in Example 3 were mixed, and 5 mm high-purity alumina grinding balls were used as grinding media. The mixture was stirred and milled at a speed of 700 r / min for 4 h, and then ground at a sand mill speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0057] S2: spray granulation was performed at a spray speed of 20,000 r / min, an inlet temperature of 220°C, and an outlet temperature of 110°C to obtain uniform ATZ composite powder;

[0058] S3: dry pressing the composite powder at 200 MPa to obtain a green body;

[0059] S4: Sintering in a protective argon atmosphere at a heating rate of 0.5°C / min, the temperature is set to 1500°C, and the temperature is kept for 4 hours to obtain high-performance zirconia ceramics.

[0060] The difference between Comparative Example 3 and Example 3 is that Fe3Al is directly mixed with the components for preparation. The zirconia ceramic obtained in Comparative Example 3 is subjected to performance testing, and its strength reaches 850 MPa. After aging at 132°C for 10 h at 0.2 MPa, the strength reaches 810 MPa, the number of hot and cold shocks at 200°C reaches 10 times, the hardness reaches 1380 Hv, the density reaches 99%, and the fracture toughness reaches 9.0 MPa*m1 / 2.

[0061] The performance results of the zirconia ceramics prepared by Examples 1-3 and Comparative Examples 1-3 show that, in the present invention, after mixing and granulating the various components of the zirconia ceramic, Fe3Al is deposited on the surface of the composite ATZ powder by magnetron sputtering, thereby ensuring the uniform dispersion effect and bonding strength of the composite powder. At the same time, since it has a similar thermal expansion coefficient to zirconia, the low-temperature thermal shock resistance of the zirconia ceramic is improved without sacrificing its fracture toughness, strength, and hardness, thereby ensuring the stability of the zirconia ceramic bearing. Compared with the traditional mixed powder making process, this method significantly improves the thermal shock resistance and strength of the ceramic.

[0062] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing zirconia ceramics, characterized in that: The following steps are involved: S1: Mix 100nm-200nm nano-zirconia, 200nm-400nm alumina, a binder, an emulsifier, and a dispersant, use high-purity alumina grinding balls as grinding media, stir and grind at a speed of 700-1000r / min for 4-8h, and then grind at a sand mill speed of 1500-2000r / min for 1-2h to obtain a mixed slurry; S2: spray granulating the mixed slurry to obtain uniform ATZ composite powder; S3: Fe3Al is deposited on the surface of the ATZ composite powder by magnetron sputtering with a deposition thickness of 0.1-0.3 μm to obtain a uniform composite powder; S4: dry-pressing the composite powder obtained in S3 to obtain a green body; S5: sintering the green body to obtain zirconia ceramics; In the S1, the mass fraction of nano-zirconium oxide is 70-90 wt %, the mass fraction of the binder is 1.5-2 wt %, the mass fraction of the emulsifier is 1.0-1.5 wt %, and the mass fraction of the dispersant is 1.5 wt %.

2. The method for preparing zirconia ceramics according to claim 1, wherein: The diameter of the high-purity alumina grinding balls in S1 is 3-5 mm.

3. The method for preparing zirconia ceramics according to claim 1, wherein: The spray speed in S2 is set to 15000-20000 r / min, the inlet temperature is set to 220±5°C, and the outlet temperature is set to 110°C±10°C.

4. The method for preparing zirconia ceramics according to claim 1, wherein: In S4, the pressure of the dry pressing is set to 200 MPa.

5. The method for preparing zirconia ceramics according to claim 1, wherein: In the step S5 , the green body is sintered at a heating rate of 0.5° C. / min under a protective argon atmosphere at a temperature of 1500° C. for 4 hours.

6. An application of a zirconia ceramic prepared by the method for preparing a zirconia ceramic according to any one of claims 1 to 5, characterized in that: The zirconia ceramics are used in the manufacture of parts for medical, aerospace, chemical, and electronic equipment.