Preparation method and application of zirconia ceramic

Abstract

The invention discloses a preparation method and application of zirconia ceramics, and relates to the technical field of zirconia ceramics, and the preparation method comprises the following steps: mixing 100-200nm nano zirconia, 200nm-400nm alumina, a binder, an emulsifier and a dispersant, adopting a high-purity alumina grinding ball as a grinding medium, stirring and grinding for 4-8 hours at a rotating speed of 700-1000r / min, and then grinding for 1-2 hours at a sanding rotating speed of 1500-2000r / min, so as to obtain the zirconia ceramics. Mixed slurry is obtained; carrying out spray granulation on the mixed slurry; the components of the zirconia ceramic are mixed and granulated, Fe3Al is deposited on the surface of the composite ATZ powder in a magnetron sputtering mode, the uniform dispersion effect and binding force of the composite powder are guaranteed, and meanwhile, due to the fact that the composite powder has a similar thermal expansion coefficient with zirconia, the composite powder has good thermal expansion performance under the condition that the fracture toughness, strength and hardness of the composite powder are not sacrificed. The low-temperature thermal shock resistance of the zirconia ceramic is improved, the stability of the zirconia ceramic bearing is ensured, and the thermal shock resistance and strength of the ceramic are remarkably improved compared with a traditional mixed powder preparation process.

Description

Technical Field

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

[0002] Zirconia ceramics have very 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 medical, aerospace, chemical, electronic and other fields. Zirconia is usually mainly yttrium-stabilized tetragonal zirconia, and there are partially stabilized zirconia ceramics, fully stabilized zirconia ceramics, and polycrystalline stabilized zirconia ceramics according to different yttrium contents. However, the mechanical properties of fully stabilized zirconia ceramics and partially stabilized zirconia ceramics are poor, and they are generally not used as structural ceramics. Polycrystalline stabilized zirconia has good mechanical properties and is often used as a structural ceramic, but polycrystalline stabilized zirconia has problems such as low-temperature aging, stress-induced aging, and environment-induced aging. The reason is that the stable tetragonal zirconia gradually transforms into monoclinic zirconia under the above conditions, and at this time, a volume expansion phenomenon occurs, inducing the generation of microcracks. When the cracks expand to a certain extent, the material fails. Therefore, a preparation method of 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 as mentioned in the above background art.

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

[0005] A preparation method of zirconia ceramics, comprising 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 rotation speed of 700 - 1000r / min for 4 - 8h, and then grind for 1 - 2h under the condition of a sanding rotation speed of 1500 - 2000r / min to obtain a mixed slurry;

[0007] S2: Spray granulate the mixed slurry to obtain a uniform ATZ composite powder;

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

[0009] S4: Dry-press the composite powder obtained in S3 to form a green body;

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

[0011] Preferably, in the step S1, the mass fraction of nano-zirconia 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, in the step S1, the diameter of the high-purity alumina grinding balls is 3-5 mm.

[0013] Preferably, in the step S2, the spray rotation speed 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 the step S4, the pressure of dry pressing is set to 200 MPa.

[0015] Preferably, in the step S5, the sintering heating rate of the green body is set to 0.5°C / min, sintering is carried out in a protective argon atmosphere, the temperature is set to 1500°C, and the heat preservation time is 4 h.

[0016] The present invention also provides an application of the zirconia ceramics, which are used in the manufacturing of parts in the medical, aerospace, chemical, and electronic fields.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. After mixing and granulating the components of the zirconia ceramics, the present invention deposits Fe3Al on the surface of the composite ATZ powder by magnetron sputtering, ensuring the uniform dispersion effect and bonding force of the composite powder. At the same time, due to its similar thermal expansion coefficient to zirconia, without sacrificing its fracture toughness, strength, and hardness, the low-temperature thermal shock resistance of the zirconia ceramics is improved, ensuring the stability of the zirconia ceramic bearings. Compared with the traditional mixed powder process, the thermal shock resistance and strength of the ceramics are significantly improved.

[0019] 2. By introducing alumina, the present invention enhances the wear resistance of the zirconia ceramics. In addition, by controlling the content and moisture content of the additives, uniform shrinkage, size, and density can be obtained during subsequent dry pressing or static pressing of the powder, increasing the consistency and controllability of subsequent processing, and making the quality and cost of the processed products very controllable. Specific Embodiments

[0020] In order to make the technical means, creative features, achieved purposes, and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

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

[0022] Example 1

[0023] S1: Mix 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% emulsifier of Y-654 type, and 1.5 wt% dispersant of D305. Use 5 mm high-purity alumina grinding balls as the grinding medium, stir and grind at a speed of 700 r / min for 4 h, and then grind for 1 h under the condition of a sanding speed of 1500 r / min to obtain a mixed slurry;

[0024] S2: Perform spray granulation under the conditions of a spray speed of 20000 r / min, an inlet temperature of 220 °C, and an outlet temperature of 110 °C to obtain a uniform ATZ composite powder;

[0025] S3: Deposit Fe3Al 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 press the composite powder obtained in S3 at 200 MPa to obtain a green body;

[0027] S5: Sinter under a protective argon atmosphere at a heating rate of 0.5 °C / min, set the temperature to 1500 °C, and hold for 4 h to obtain high-performance zirconia ceramics.

[0028] Perform performance tests on the zirconia ceramics obtained in Example 1. Its strength reaches 1200 MPa, after aging at 132 °C for 10 h under 0.2 Mpa, the strength reaches 1180 MPa, the number of thermal shock cycles at 200 °C reaches 20 times, the hardness reaches 1450 Hv, the relative density reaches 99%, and the fracture toughness reaches 10 MPa*m 1 / 2 。

[0029] Example 2

[0030] S1: Mix 200 nm nano-zirconia with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% emulsifier of Y-654 type, and 1.5 wt% dispersant of D305. Use 5 mm high-purity alumina grinding balls as the grinding medium, stir and grind at a speed of 700 r / min for 4 h, and then grind for 1 h under the condition of a sanding speed of 1500 r / min to obtain a mixed slurry;

[0031] S2: Spray granulation is carried out under the conditions of a spray rotation 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: By means of magnetron sputtering, Fe3Al is deposited on the surface of the composite ATZ powder with a deposition thickness of 0.2 μm to obtain uniform composite powder;

[0033] S4: The composite powder obtained in S3 is dry-pressed into a green body at 200 MPa;

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

[0035] The difference between Example 2 and Example 1 is that the thickness of magnetron-sputtered Fe3Al is increased to 0.2 μm. The performance of the zirconia ceramics obtained in Example 2 is tested. Its strength reaches 1200 MPa. After aging at 132 °C for 10 h under 0.2 Mpa, the strength reaches 1150 Mpa. The number of thermal shock cycles at 200 °C reaches 21 times. The hardness reaches 1440 Hv, the relative density reaches 99%, and the fracture toughness reaches 11.5 mpa*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 type emulsifier, and 1.5 wt% D305 dispersant are mixed. 5 mm high-purity alumina grinding balls are used as the grinding medium, and stirring milling is carried out at a rotation speed of 700 r / min for 4 h. Then, under the condition of a sand milling rotation speed of 1500 r / min, grinding is carried out for 1 h to obtain a mixed slurry;

[0038] S2: Spray granulation is carried out under the conditions of a spray rotation 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: By means of magnetron sputtering, Fe3Al is deposited on the surface of the composite ATZ powder with a deposition thickness of 0.3 μm to obtain uniform composite powder;

[0040] S4: The composite powder obtained in S3 is dry-pressed into a green body at 200 MPa;

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

[0042] Example 3 is different from Example 1 in that the thickness of magnetron sputtered Fe3Al is increased to 0.3 μm. The properties of the zirconia ceramics obtained in Example 3 were tested. Its strength reached 1200 MPa. After aging at 132 °C for 10 h under 0.2 Mpa, the strength reached 1130 MPa. The number of thermal shock cycles at 200 °C reached 25 times. The hardness reached 1430 Hv, the relative density reached 99%, and the fracture toughness reached 11.4 MPa·m1 / 2. 1 / 2 。

[0043] Comparative Example 1

[0044] S1: Mix 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. Use 5 mm high-purity alumina grinding balls as the grinding medium, stir and grind at 700 r / min for 4 h, and then grind at a sanding speed of 1500 r / min for 1 h to obtain a mixed slurry.

[0045] S2: Perform spray granulation at a spray speed of 20000 r / min, an inlet temperature of 220 °C, and an outlet temperature of 110 °C to obtain a uniform ATZ composite powder.

[0046] S3: Dry press the composite powder at 200 MPa to obtain a green body.

[0047] S4: Sinter at a heating rate of 0.5 °C / min under a protective argon atmosphere, set the temperature to 1500 °C, and hold for 4 h to obtain high-performance zirconia ceramics.

[0048] The difference between Comparative Example 1 and Example 1 is that Fe3Al was directly mixed with each component for preparation. The properties of the zirconia ceramics obtained in Comparative Example 1 were tested. Its strength reached 900 MPa. After aging at 132 °C for 10 h under 0.2 Mpa, the strength reached 850 MPa. The number of thermal shock cycles at 200 °C reached 5 times. The hardness reached 1400 Hv, the relative density reached 99%, and the fracture toughness reached 9.5 MPa·m1 / 2.

[0049] Comparative Example 2

[0050] S1: Mix 200 nm zirconia nanoparticles with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% emulsifier of Y-654 type, 1.5 wt% dispersant of D305, and the same amount of Fe3Al as in Example 2. Use 5 mm high-purity alumina grinding balls as the grinding medium, stir and mill at 700 r / min for 4 h, and then grind at a sanding speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0051] S2: Conduct spray granulation at a spray speed of 20000 r / min, an inlet temperature of 220 °C, and an outlet temperature of 110 °C to obtain a uniform ATZ composite powder;

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

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

[0054] The difference between Comparative Example 2 and Example 2 is that Fe3Al is directly mixed with each component for preparation. The performance of the zirconia ceramics obtained in Comparative Example 2 is tested. Its strength reaches 890 MPa, after aging at 132 °C for 10 h under 0.2 Mpa, the strength reaches 840 mpa, the number of thermal shock cycles 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: Mix 200 nm zirconia nanoparticles with a mass fraction of 80 wt%, 200 nm alumina, 2 wt% PVA2000 binder, 1.5 wt% emulsifier of Y-654 type, 1.5 wt% dispersant of D305, and the same amount of Fe3Al as in Example 3. Use 5 mm high-purity alumina grinding balls as the grinding medium, stir and mill at 700 r / min for 4 h, and then grind at a sanding speed of 1500 r / min for 1 h to obtain a mixed slurry;

[0057] S2: Conduct spray granulation at a spray speed of 20000 r / min, an inlet temperature of 220 °C, and an outlet temperature of 110 °C to obtain a uniform ATZ composite powder;

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

[0059] S4: Sinter at a heating rate of 0.5 °C / min under a protective argon atmosphere. Set the temperature to 1500 °C and hold for 4 h to obtain high-performance zirconia ceramics.

[0060] The difference between Comparative Example 3 and Example 3 is that Fe3Al is directly mixed with each component for preparation. The performance of the zirconia ceramics obtained in Comparative Example 3 is tested. Its strength reaches 850 MPa. After aging at 132 °C for 10 h under 0.2 Mpa, the strength reaches 810 mpa. The number of thermal shock cycles at 200 °C reaches 10 times. The hardness reaches 1380 Hv. The relative density reaches 99%. The fracture toughness reaches 9.0 mpa*m1 / 2.

[0061] From the performance results of the zirconia ceramics prepared by Examples 1-3 and Comparative Examples 1-3, it can be seen that in the present invention, after granulating the components of the zirconia ceramics, Fe3Al is deposited on the surface of the composite ATZ powder by magnetron sputtering to ensure the uniform dispersion effect and bonding force of the composite powder. At the same time, due to its similar thermal expansion coefficient to zirconia, without sacrificing its fracture toughness, strength, and hardness, the low-temperature thermal shock resistance of the zirconia ceramics is improved, and the stability of the zirconia ceramic bearings is ensured. Compared with the traditional mixed powder process, the thermal shock resistance and strength of the ceramics are significantly improved.

[0062] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present 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 zirconium oxide, 200nm-400nm alumina, a binder, an emulsifier, and a dispersant, use high-purity alumina grinding balls as grinding media, stir and grind for 4-8h at a speed of 700-1000r / min, and then grind for 1-2h at a sand mill speed of 1500-2000r / min 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 composite ATZ 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.

2. The method for preparing zirconia ceramics according to claim 1, characterized in that: In the S1, the mass fraction of nano zirconium oxide is 70-90wt%, the mass fraction of the binder is 1.5-2wt%, the mass fraction of the emulsifier is 1.0-1.5wt%, and the mass fraction of the dispersant is 1.5wt%.

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

4. The method for preparing zirconia ceramics according to claim 1, characterized in that: 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.

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

6. The method for preparing zirconia ceramics according to claim 1, characterized in that: In the step S5, the sintering heating rate of the green embryo is set to 0.5°C / min, and the green embryo is sintered in a protective argon atmosphere at a temperature of 1500°C for 4 hours.

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