Modified silicon carbide special ceramic material and preparation method thereof

Abstract

The invention discloses a modified silicon carbide special ceramic material and a preparation method thereof, and belongs to the technical field of ceramic materials. The special ceramic material is prepared from the following raw materials in parts by weight: 80-100 parts of silicon carbide powder, 2-5 parts of chromic oxide, 5-10 parts of zirconium oxide, 3-8 parts of nickel oxide, 3-7 parts of boron nitride, 0.2-0.5 part of a binder and 1-4 parts of a lubricant. The special ceramic material prepared by the invention has relatively high hardness, excellent fracture toughness, extremely low density, wear resistance and extremely low thermal expansion coefficient, has a wide application prospect in practice, is simple in preparation method, and can be subjected to large-scale industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic materials, and particularly relates to a modified silicon carbide special ceramic material and a preparation method thereof. Background Art

[0002] The different chemical compositions and microstructures of special ceramics determine their different special properties and functions, such as high strength, high hardness, high toughness, corrosion resistance, electrical conductivity, insulation, magnetism, light transmission, semiconductors, and piezoelectric, optoelectronic, electro-optical, acousto-optical, magneto-optical, etc. Due to their special properties, such ceramics can be used as engineering structural materials and functional materials in machinery, electronics, chemical industry, smelting, energy, medicine, laser, nuclear reaction, aerospace and other fields. Some economically developed countries have invested a large amount of manpower, material and financial resources in researching and developing special ceramics in order to accelerate the new technological revolution and lay a material foundation for the development of new industries. Therefore, the development of special ceramics is very rapid and there have been great breakthroughs in technology. Special ceramics are becoming increasingly important in modern industrial technology, especially in the high-tech and new technology fields.

[0003] At present, the existing preparation methods of special ceramics include two methods: dry forming and wet forming. Dry forming includes methods such as dry pressing, isostatic pressing, ultra-high pressure pressing, powder electromagnetic forming, etc. Wet forming generally includes plastic forming and colloidal casting forming.

[0004] In the prior art, due to the insufficient performance in terms of hardness, fracture toughness, flexural strength, density, thermal expansion coefficient, working temperature and wear resistance, when special ceramics are applied to nuclear fuel pellet stamping dies, there are problems of large wear and poor use effect. Summary of the Invention

[0005] The technical problems to be solved by the present invention are to provide a modified silicon carbide special ceramic material with corrosion resistance, good toughness, impact resistance and high strength performance; another technical problem to be solved by the present invention is to provide a preparation method of a modified silicon carbide special ceramic material, which optimizes the existing ceramic preparation process, selects appropriate process parameters, and makes the performance of the new special ceramic material more stable.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0008] 1) Mix silicon carbide powder, chromium oxide, zirconia and nickel oxide in proportion, add them to a ball mill for grinding, then add methanol and continue grinding, granulate, sieve, perform cold isostatic pressing, and gas pressure sintering to obtain modified silicon carbide powder;

[0009] 2) Using helium as a protective gas, calcine the modified silicon carbide powder obtained in step 1), then air-cool it to room temperature, and send it to a ball mill for grinding to obtain modified silicon carbide powder particles;

[0010] 3) Mix and stir the modified silicon carbide powder particles, boron nitride, binder, and lubricant obtained in step 2), calcine, and ball mill and crush them to obtain special ceramic particles;

[0011] 4) Mix the special ceramic particles obtained in step 3) with deionized water, then put them into a ball mill for ball milling, shaping, calcine in an atmosphere of helium, then increase the temperature for calcination, and finally air-cool to room temperature to obtain a special ceramic material.

[0012] Further, in step 1), it is made of the following raw materials in parts by weight: 80-100 parts of silicon carbide powder, 2-5 parts of chromium sesquioxide, 5-10 parts of zirconia, 3-8 parts of nickel oxide, 3-7 parts of boron nitride, 0.2-0.5 parts of binder, and 1-4 parts of lubricant.

[0013] Further, in step 1), the lubricant is zinc stearate and calcium stearate.

[0014] Further, in step 1), the mesh number of ball milling and sieving is 230-250 meshes, and the ball milling time is 15-20 h.

[0015] Further, in step 1), the cold isostatic pressure is 250-300 Mpa, the pressure of gas pressure sintering is 3-7 Mpa, the sintering temperature is 1500-1800 °C, and the heat preservation time is 1-2 h.

[0016] Further, in step 2), the mesh number of ball milling and sieving is 100-120 meshes, the calcination temperature is 900-1000 °C, and the calcination time is 5-6 h.

[0017] Further, in step 3), the binder is polyvinyl alcohol, paraffin wax, and polyethylene glycol.

[0018] Further, in step 3), the mesh number of ball milling and sieving is 80 meshes, the calcination temperature is 980-990 °C, and the calcination time is 2-3 h.

[0019] Further, in step 4), the ratio of special ceramic particles to deionized water is 4:3, the ball milling time is 15-20 h, the calcination temperature is 800-1300 °C, and the calcination time is 2-5 h.

[0020] Further, the special ceramic material is prepared by the preparation method of the modified silicon carbide special ceramic material.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] (1) In the present invention, silicon carbide powder is modified with chromium sesquioxide, zirconia and nickel oxide. As a component of the raw materials, chromium sesquioxide can not only improve the strength of the ceramic material, but also enhance the impact resistance of the ceramic; zirconia improves the toughening performance of the ceramic material; the addition of nickel oxide can effectively improve the corrosion resistance and wear resistance of the ceramic.

[0023] (2) Adding boron nitride to the raw materials of the present invention can improve the impact resistance of the ceramic, reduce the possibility of the ceramic cracking when the temperature reaches the extreme, and improve the stability of the ceramic. In addition, due to the layered crystal structure similar to that of graphite, boron nitride endows the ceramic with good electrical insulation and thermal expansion coefficient performance.

[0024] (3) The preparation method of the present invention is simple and low-cost. Through processes such as batching, forming, and sintering, the prepared special ceramic material has strong mechanical properties and is suitable for large-scale production. Specific Embodiments

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below in conjunction with specific examples.

[0026] Unless otherwise specified, the materials used in the following examples are all commercially available products.

[0027] Example 1

[0028] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0029] (1) Mix 80 parts of silicon carbide powder, 2 parts of chromium sesquioxide, 5 parts of zirconia, and 3 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230 - 250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 15 h, granulate, pass through a sieve, and perform cold isostatic pressing. The pressure of cold isostatic pressing is 250 Mpa. Adopt the gas pressure sintering method, the pressure is 3 Mpa, the sintering temperature is 1500 °C, and the holding time is 1 h to obtain modified silicon carbide powder;

[0030] (2) Use helium as the protective gas for the modified silicon carbide powder obtained in step (1), calcine at 900 - 1000 °C for 5 h, then air-cool to room temperature, send it to a ball mill for grinding, and pass through a 100 - 120 mesh sieve to obtain modified silicon carbide powder particles;

[0031] (3) Mix and stir the modified silicon carbide powder particles obtained in step (2), 3 parts of boron nitride, 0.2 parts of polyvinyl alcohol, and 1 part of zinc stearate, calcine at 980 - 990 °C for 2 h, ball mill and pulverize, and pass through an 80 mesh sieve to obtain special ceramic particles;

[0032] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put them into a ball mill and mill for 15 - 16 h, then shape them, and calcine them at 800 - 900 °C for 2 h in an atmosphere of helium, then raise the temperature to 1300 °C and calcine for 5 h, hold for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0033] Example 2

[0034] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0035] (1) Mix 86 parts of silicon carbide powder, 3 parts of chromium sesquioxide, 6 parts of zirconia and 5 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230 - 250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 16 h, granulate, pass through a sieve, carry out cold isostatic pressing, the pressure of cold isostatic pressing is 270 Mpa, adopt the gas pressure sintering method, the pressure is 4 Mpa, the sintering temperature is 1600 °C, and the holding time is 1 h to obtain the modified silicon carbide powder;

[0036] (2) Use helium as the protective gas for the modified silicon carbide powder obtained in step (1), calcine at 900 - 1000 °C for 5 h, then air-cool to room temperature, send it into a ball mill for grinding, and pass through a 100 - 120 mesh sieve to obtain the modified silicon carbide powder particles;

[0037] (3) Mix and stir the modified silicon carbide powder particles obtained in step (2), 4 parts of boron nitride, 0.3 part of polyethylene glycol and 2 parts of calcium stearate, calcine at 980 - 990 °C for 2 h, ball mill and crush, and pass through an 80 - mesh sieve to obtain the special ceramic particles;

[0038] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put them into a ball mill and mill for 16 - 17 h, then shape them, and calcine them at 800 - 900 °C for 3 h in an atmosphere of helium, then raise the temperature to 1300 °C and calcine for 5 h, hold for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0039] Example 3

[0040] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0041] (1) Mix 95 parts of silicon carbide powder, 4 parts of chromium sesquioxide, 8 parts of zirconia and 6 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230 - 250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 18 h, granulate, pass through a sieve, carry out cold isostatic pressing, the pressure of cold isostatic pressing is 280 Mpa, adopt the gas pressure sintering method, the pressure is 6 Mpa, the sintering temperature is 1700 °C, and the holding time is 1.5 h to obtain the modified silicon carbide powder;

[0042] (2) Using helium as a protective gas, calcine the modified silicon carbide powder obtained in step (1) at 900 - 1000 °C for 6 h, then air-cool to room temperature, send it to a ball mill for grinding, and pass through a 100 - 120 mesh sieve to obtain modified silicon carbide powder particles;

[0043] (3) Mix and stir 5 parts of boron nitride, 0.4 part of paraffin wax, and 3 parts of zinc stearate with the modified silicon carbide powder particles obtained in step (2), calcine at 980 - 990 °C for 3 h, ball mill and pulverize, and pass through an 80 mesh sieve to obtain special ceramic particles;

[0044] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put it into a ball mill and ball mill for 17 - 18 h, then mold it, calcine at 800 - 900 °C for 3 h in a helium atmosphere, then raise the temperature to 1300 °C and calcine for 5 h, hold for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0045] Example 4

[0046] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0047] (1) Mix 100 parts of silicon carbide powder, 5 parts of chromium sesquioxide, 10 parts of zirconia, and 8 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230 - 250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 20 h, granulate, sieve, perform cold isostatic pressing, the pressure of cold isostatic pressing is 300 Mpa, adopt gas pressure sintering method, the pressure is 7 Mpa, the sintering temperature is 1800 °C, and the holding time is 2 h to obtain modified silicon carbide powder;

[0048] (2) Using helium as a protective gas, calcine the modified silicon carbide powder obtained in step (1) at 900 - 1000 °C for 6 h, then air-cool to room temperature, send it to a ball mill for grinding, and pass through a 100 - 120 mesh sieve to obtain modified silicon carbide powder particles;

[0049] (3) Mix and stir 7 parts of boron nitride, 0.5 part of paraffin wax, and 4 parts of sodium zinc stearate with the modified silicon carbide powder particles obtained in step (2), calcine at 980 - 990 °C for 3 h, ball mill and pulverize, and pass through an 80 mesh sieve to obtain special ceramic particles;

[0050] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put it into a ball mill and ball mill for 18 - 20 h, then mold it, calcine at 800 - 900 °C for 3 h in a helium atmosphere, then raise the temperature to 1300 °C and calcine for 5 h, hold for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0051] Comparative Example 1

[0052] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0053] (1) Mix 95 parts of silicon carbide powder, 4 parts of chromium sesquioxide and 8 parts of zirconia, add them to a ball mill for grinding, pass through a 230-250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 18 h, granulate, sieve, perform cold isostatic pressing, the pressure of cold isostatic pressing is 280 Mpa, adopt gas pressure sintering method, the pressure is 6 Mpa, the sintering temperature is 1700 °C, and the heat preservation time is 1.5 h to obtain modified silicon carbide powder;

[0054] (2) Use helium as a protective gas for the modified silicon carbide powder obtained in step (1), calcine at 900-1000 °C for 6 h, then air-cool to room temperature, send it to a ball mill for grinding, and pass through a 100-120 mesh sieve to obtain modified silicon carbide powder particles;

[0055] (3) Mix and stir the modified silicon carbide powder particles obtained in step (2), 5 parts of boron nitride, 0.4 part of paraffin and 3 parts of zinc stearate, calcine at 980-990 °C for 3 h, ball mill and pulverize, and pass through an 80 mesh sieve to obtain special ceramic particles;

[0056] (4) Mix the special ceramic particles obtained in step (3) with deionized water according to a mass ratio of 4:3, then put them into a ball mill and ball mill for 17-18 h, then mold, and calcine in a helium atmosphere at 800-900 °C for 3 h, then raise the temperature to 1300 °C and calcine for 5 h, keep warm for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0057] Comparative Example 2

[0058] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0059] (1) Mix 95 parts of silicon carbide powder, 4 parts of chromium sesquioxide and 6 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230-250 mesh sieve, then add an appropriate amount of methanol and continue grinding for 18 h, granulate, sieve, perform cold isostatic pressing, the pressure of cold isostatic pressing is 280 Mpa, adopt gas pressure sintering method, the pressure is 6 Mpa, the sintering temperature is 1700 °C, and the heat preservation time is 1.5 h to obtain modified silicon carbide powder;

[0060] (2) Use helium as a protective gas for the modified silicon carbide powder obtained in step (1), calcine at 900-1000 °C for 6 h, then air-cool to room temperature, send it to a ball mill for grinding, and pass through a 100-120 mesh sieve to obtain modified silicon carbide powder particles;

[0061] (3) Mix and stir the modified silicon carbide powder particles obtained in step (2), 5 parts of boron nitride, 0.4 part of paraffin wax, and 3 parts of zinc stearate, calcine at 980 - 990 °C for 3 h, grind and pulverize by ball milling, and pass through a 80-mesh sieve to obtain special ceramic particles;

[0062] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put them into a ball mill and ball mill for 17 - 18 h, then shape them, calcine in an atmosphere of helium at 800 - 900 °C for 3 h, then raise the temperature to 1300 °C and calcine for 5 h, hold the temperature for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0063] Comparative Example 3

[0064] A preparation method of a modified silicon carbide special ceramic material, comprising the following steps:

[0065] (1) Mix 95 parts of silicon carbide powder, 8 parts of zirconia, and 6 parts of nickel oxide, add them to a ball mill for grinding, pass through a 230 - 250-mesh sieve, then add an appropriate amount of methanol and continue grinding for 18 h, granulate, pass through a sieve, perform cold isostatic pressing, the pressure of cold isostatic pressing is 280 Mpa, adopt the gas pressure sintering method, the pressure is 6 Mpa, the sintering temperature is 1700 °C, and the holding time is 1.5 h to obtain the modified silicon carbide powder;

[0066] (2) Take the modified silicon carbide powder obtained in step (1) with helium as the protective gas, calcine at 900 - 1000 °C for 6 h, then air-cool to room temperature, send it into a ball mill for grinding, and pass through a 100 - 120-mesh sieve to obtain modified silicon carbide powder particles;

[0067] (3) Mix and stir the modified silicon carbide powder particles obtained in step (2), 5 parts of boron nitride, 0.4 part of paraffin wax, and 3 parts of zinc stearate, calcine at 980 - 990 °C for 3 h, grind and pulverize by ball milling, and pass through a 80-mesh sieve to obtain special ceramic particles;

[0068] (4) Mix the special ceramic particles obtained in step (3) with deionized water at a mass ratio of 4:3, then put them into a ball mill and ball mill for 17 - 18 h, then shape them, calcine in an atmosphere of helium at 800 - 900 °C for 3 h, then raise the temperature to 1300 °C and calcine for 5 h, hold the temperature for 1 h, and finally air-cool to room temperature to obtain the special ceramic material.

[0069] Perform performance tests on Examples 1 - 4 and Comparative Examples 1 - 3, and the test results are shown in Table 1 below.

[0070] Table 1 Data table of performance test results

[0071]

[0072] As can be seen from Table 1 above, the special ceramic material prepared by the present invention has high hardness, excellent fracture toughness, extremely low density, wear resistance, extremely low thermal expansion coefficient and good flexural strength.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a modified silicon carbide special ceramic material, characterized in that: It includes the following steps: 1) Mix silicon carbide powder, chromium(III) oxide, zirconia and nickel oxide in proportion, add them to a ball mill for powder grinding, then add methanol and continue grinding, granulate, sieve, perform cold isostatic pressing and gas pressure sintering to obtain modified silicon carbide powder; 2) Use helium as a protective gas to calcine the modified silicon carbide powder obtained in step 1), then air-cool to room temperature and send it to a ball mill for powder grinding to obtain modified silicon carbide powder particles; 3) Mix and stir the modified silicon carbide powder particles, boron nitride, binder and lubricant obtained in step 2), calcine and ball mill and crush to obtain special ceramic particles; 4) Mix the special ceramic particles obtained in step 3) with deionized water, then put them into a ball mill for ball milling, shape, calcine in a helium atmosphere, then increase the temperature for calcination, and finally air-cool to room temperature to obtain special ceramic materials.

2. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 1), it is made of the following raw materials by weight: 80 - 100 parts of silicon carbide powder, 2 - 5 parts of chromium(III) oxide, 5 - 10 parts of zirconia, 3 - 8 parts of nickel oxide, 3 - 7 parts of boron nitride, 0.2 - 0.5 parts of binder, and 1 - 4 parts of lubricant.

3. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 1), the lubricant is zinc stearate and calcium stearate.

4. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 1), the mesh number of ball milling and sieving is 230 - 250 mesh, and the ball milling time is 15 - 20 h.

5. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 1), the cold isostatic pressure is 250 - 300 Mpa, the pressure of gas pressure sintering is 3 - 7 Mpa, the sintering temperature is 1500 - 1800 °C, and the heat preservation time is 1 - 2 h.

6. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 2), the mesh number of ball milling and sieving is 100 - 120 mesh, the calcination temperature is 900 - 1000 °C, and the calcination time is 5 - 6 h.

7. The preparation method of the modified silicon carbide special ceramic material according to claim 1, characterized in that: In step 3), the binder is polyvinyl alcohol, paraffin wax, and polyethylene glycol.

8. The preparation method of the modified silicon carbide special ceramic material according to claim 1, wherein: In step 3), the mesh number of ball milling and sieving is 80 mesh, the calcination temperature is 980 - 990 °C, and the calcination time is 2 - 3 h.

9. The preparation method of the modified silicon carbide special ceramic material according to claim 1, wherein: In step 4), the ratio of special ceramic particles to deionized water is 4:3, the ball milling time is 15 - 20 h, the calcination temperature is 800 - 1300 °C, and the calcination time is 2 - 5 h.

10. The special ceramic material is prepared by the preparation method of the modified silicon carbide special ceramic material according to any one of claims 1 - 9.

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