Preparation method and application of silicon carbide ceramic

Abstract

The invention relates to the technical field of silicon carbide ceramics. The preparation method comprises the following steps: S1, weighing 70-90% by weight of silicon carbide, 5-15% by weight of an adhesive, 2-5% by weight of a recrystallization auxiliary agent, 0.5-1% by weight of a deoxidizing agent and 5-10% by weight of a filling agent, S2, carrying out ball milling treatment on the raw materials to obtain a mixture, S3, carrying out injection molding on the mixture to obtain a sheet-shaped material, and S4, carrying out heat treatment on the sheet-shaped material to obtain the silicon carbide ceramic. S4, carrying out pressing treatment on the flaky material to obtain a green body; and S5, carrying out heating, heat preservation and sintering treatment on the green body in an inert atmosphere to finally obtain the silicon carbide ceramic. By adding a proper amount of recrystallization aid and deoxidizer into the raw materials, growth of silicon carbide crystal grains can be effectively promoted, formation of pores and defects is avoided, and thus the mechanical property and the service life of the silicon carbide ceramic are improved. Various raw materials can be uniformly mixed together through ball milling treatment, the density of the green body is further improved in the pressing process, and the quality of the silicon carbide ceramic is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of silicon carbide ceramics, and in particular to a method for preparing silicon carbide ceramics and applications of silicon carbide ceramics. Background Art

[0002] Silicon carbide ceramics have high hardness and high strength, and can be used to manufacture wear-resistant mechanical parts such as mechanical seals, bearings, balls, cutting tools, etc. They can work stably for a long time under harsh working conditions of high wear and high friction, reducing the maintenance and replacement frequency of equipment. For example, in mechanical equipment in the papermaking, mining, cement and other industries, wear-resistant parts made of silicon carbide ceramics can effectively improve the service life and production efficiency of the equipment. Its good strength and stiffness make it suitable for manufacturing structural parts with high requirements on the mechanical properties of materials, such as parts of automobile engines, certain structural parts in the aerospace field, etc., which can ensure the stability and reliability of the structure while reducing weight. The high thermal conductivity makes it have broad application prospects in the field of heat exchangers, which can quickly transfer heat and improve heat exchange efficiency. For example, in the waste heat recovery system of the chemical, metallurgical and other industries, silicon carbide ceramic heat exchangers can effectively convert waste heat into usable thermal energy and reduce energy waste. It can also be used as an electronic packaging material for packaging electronic components such as integrated circuits and chips, which can provide good protection and heat dissipation for electronic components.

[0003] In the prior art, silicon carbide ceramics are often prepared by hot pressing sintering, pressureless sintering, chemical vapor deposition and other methods. Different production methods and process parameters have a great influence on the performance of silicon carbide ceramics, and slight changes in the production process may lead to unstable product performance. For example, factors such as sintering temperature, sintering time, type and amount of additives will affect the density, porosity, strength and other properties of silicon carbide ceramics. Therefore, it is necessary to strictly control the process parameters in the production process to ensure the stability of product performance. Chemical vapor deposition requires the use of a large amount of toxic gases and chemical reagents. Waste gas, waste water and other pollutants will be generated during the production process, which has a great impact on the environment. It is impossible to produce large pieces of ceramics, and the cost is very high. The above methods have a great impact on the precision molding of silicon carbide ceramics. Summary of the invention

[0004] In order to solve the shortcomings of the prior art, the present invention discloses a method for preparing silicon carbide ceramics and applications of silicon carbide ceramics, which overcome the problem that chemical vapor deposition cannot produce large ceramics during the production process, do not require the use of toxic gases and toxic chemical reagents during the production process, and have high precision and good stability in the prepared silicon carbide ceramics.

[0005] The invention discloses a method for preparing silicon carbide ceramics, which comprises: S1: weighing by weight: 70-90% of silicon carbide, 5-15% of a binder, 2-5% of a recrystallization aid, 0.5-1% of a deoxidizer and 5-10% of a filler, S2: subjecting the raw materials to ball milling to obtain a mixture, S3: injection molding the mixture into a sheet material, S4: subjecting the sheet material to pressing to obtain a green body, and S5: subjecting the green body to heating, heat preservation and sintering in an inert atmosphere to finally obtain silicon carbide ceramics.

[0006] Furthermore, the adhesive is selected from one or a mixture of polyester polyol, polyethylene glycol, oxidized polyethylene or polypropylene, the filler is selected from at least one of talc, potassium feldspar or sodium feldspar, the deoxidizer is selected from at least one of aluminum powder, copper powder, iron powder or magnesium powder, and the recrystallization aid is selected from at least one of silicon dioxide, zinc oxide or titanium dioxide.

[0007] Furthermore, the particle size of silicon carbide is 5-55 μm, the particle size of the filler is 5-40 μm, and the particle size of the recrystallization aid is 5-15 μm.

[0008] Furthermore, the ball milling treatment in S2 uses a ball mill, the rotation speed of the ball mill is set to 150-220r / min, and the ball milling time is 20-40h. In S3, an injection molding machine is used to injection mold the mixed material into a sheet material. In S4, the sheet material is pressed by a hydraulic press, and the pressure of the hydraulic press is set to 100-1000T.

[0009] Further, in S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h, heated to 400-1000°C at a heating rate of 80-120°C / h, heated to 1200-2200°C at a heating rate of 3-15°C / h under a nitrogen atmosphere, and sintered for 3-7h to obtain silicon carbide ceramics.

[0010] Further, in S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h, heated to 750-850°C at a heating rate of 80-120°C / h, heated to 1400-1600°C at a heating rate of 3-15°C / h under a nitrogen atmosphere, and sintered for 3-7h to obtain silicon carbide ceramics.

[0011] Furthermore, S3 further includes a preheating step before injection molding the mixed material into a sheet material, the preheating temperature is 50-100° C., and the preheating time is 10-30 minutes.

[0012] The present invention discloses an application of silicon carbide ceramics, which is prepared by any of the preparation methods of silicon carbide ceramics described above, and is characterized in that it includes: applications of silicon carbide ceramics in the fields of mechanical engineering, aerospace, automobile manufacturing, chemical industry, metallurgy, electronic packaging and environmental protection.

[0013] Beneficial effects of the present invention:

[0014] The present invention draws on the process of forming precision devices by injection molding of polymer materials, and then obtains a good silicon carbide ceramic substrate by compacting under pressure and recrystallizing at high temperature. Because of the addition of polymer adhesive and the injection molding process, the problems of imprecise process control and easy hidden cracks in hot pressing sintering and pressureless sintering methods are avoided. It also overcomes the problems of chemical vapor deposition method that large pieces of ceramics cannot be produced, the environment is harmful, and the cost is extremely high. The prepared ceramic sheet can be used for water treatment, subsequent preparation of heat sinks, and various structural parts.

[0015] The present application adds an appropriate amount of recrystallization aid and deoxidizer to the raw materials, which can effectively promote the growth of silicon carbide grains and avoid the formation of pores and defects, thereby improving the mechanical properties and service life of the material. The present application uses ball milling to evenly mix various raw materials, ensuring that the microstructure of the final product is more uniform, and the pressing process further increases the density of the green body, which can improve the densification of the material in the subsequent sintering process. Heating, heat preservation and sintering treatment in an inert atmosphere can effectively prevent oxidation of silicon carbide at high temperatures, and can better control the phase change and microstructure development of the material during the sintering process, thereby ensuring the quality of the final prepared silicon carbide ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a SEM image of the silicon carbide surface after compaction in Example 1 of the implementation scheme of the present application.

[0017] Figure 2 It is the aluminum silicon carbide prepared in Application Example 2 in the implementation manner of this application. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the specific implementation modes of the present invention will be clearly and completely described below.

[0019] The present application discloses a method for preparing silicon carbide ceramics, which specifically includes S1: weighing 70-90% silicon carbide, 5-15% adhesive, 2-5% recrystallization aid, 0.5-1% deoxidizer and 5-10% filler by weight, S2: ball milling the raw materials to obtain a mixture, S3: injection molding the mixture into a sheet material, S4: pressing the sheet material to obtain a green body, S5: heating, heat preservation and sintering the green body under an inert atmosphere to finally obtain silicon carbide ceramics. The present application adds an appropriate amount of recrystallization aid and deoxidizer to the raw materials, which can effectively promote the growth of silicon carbide grains, avoid the formation of pores and defects, and thus improve the mechanical properties and service life of the material. The present application uses ball milling to evenly mix various raw materials, ensuring that the microstructure of the final silicon carbide ceramic is more uniform, and the pressing process further increases the density of the green body, which can improve the densification degree of the material in the subsequent sintering process. Heating, heat preservation and sintering treatments are carried out in an inert atmosphere, which can effectively prevent the oxidation of silicon carbide at high temperatures, and can better control the phase change and microstructure development of the material during the sintering process, thereby ensuring the quality of the final prepared silicon carbide ceramic.

[0020] As an embodiment, the binder is selected from one or a mixture of polyester polyol, polyethylene glycol, oxidized polyethylene or polypropylene, the filler is selected from at least one of talc, potassium feldspar or sodium feldspar, the deoxidizer is selected from at least one of aluminum powder, copper powder, iron powder or magnesium powder, and the recrystallization aid is selected from at least one of silicon dioxide, zinc oxide or titanium dioxide. Organic polymers such as ester polyols and polyethylene glycol as binders can provide good fluidity in the injection molding stage, which is convenient for processing. At the same time, they can be completely volatilized in the subsequent sintering process without leaving residues that affect the performance of the ceramic. Oxidized polyethylene or polypropylene provides good mechanical strength, and can keep the shape of the green body stable after injection molding to prevent deformation. Talc, potassium feldspar or sodium feldspar as fillers can improve the heat resistance and mechanical strength of the material. At the same time, their presence can also help adjust the thermal expansion coefficient of the material and reduce the risk of cracking due to temperature changes. Metal powders such as aluminum powder, copper powder, iron powder or magnesium powder as deoxidizers can react with oxygen in the material during the sintering process to reduce the oxygen content, thereby reducing the oxide inclusions inside the material and improving the purity and density of the material. Silicon dioxide, zinc oxide or titanium dioxide as recrystallization aids can promote the growth of silicon carbide grains during the sintering process and prevent the performance of silicon carbide ceramics from deteriorating due to excessive grain growth. At the same time, these additives can also help silicon carbide ceramics form a dense microstructure and improve the hardness and wear resistance of silicon carbide ceramics.

[0021] As an embodiment, the particle size of silicon carbide is 5-55 μm, the particle size of the filler is 5-40 μm, and the particle size of the recrystallization aid is 5-15 μm. When the particle size of silicon carbide is 5-55 μm, it can provide sufficient surface area to interact with other components and promote densification. Larger silicon carbide particles help to increase the hardness and wear resistance of silicon carbide ceramics, while smaller silicon carbide particles help to improve the density and smoothness of silicon carbide ceramics. When the particle size of the filler is 5-40 μm, it can effectively fill the gaps between silicon carbide particles and improve the density of the green body. Finer fillers can also improve the uniformity of silicon carbide ceramics and reduce defects, which can improve the mechanical properties of the final silicon carbide ceramics. The particle size of the recrystallization aid is 5-15 μm, which can be evenly distributed in the mixture, promoting the growth of silicon carbide grains while preventing the grains from growing excessively.

[0022] As an implementation method, the ball milling treatment in S2 uses a ball mill, the speed of the ball mill is set to 150-220r / min, the ball milling time is 20-40h, the injection molding machine is used in S3 to inject the mixture into a sheet material, and the sheet material is pressed by a hydraulic press in S4, and the pressure of the hydraulic press is set to 100-1000T. Ball milling can make the mixing of silicon carbide, fillers, adhesives, etc. more uniform, and the presence of large particles can be reduced after ball milling, thereby improving the density and smoothness of the final silicon carbide ceramics. Ball milling sets the ball milling time to 20-40h to remove air from the mixture, reduce porosity, and thus improve the quality of silicon carbide ceramics. The hydraulic press can provide constant pressure, and appropriate high pressure can significantly improve the density of the green body, reduce the amount of shrinkage during sintering, and thus improve the dimensional accuracy of silicon carbide ceramics. Higher pressure can also help eliminate air in the mixture, reduce the porosity in the sintered material, and improve the mechanical properties of silicon carbide ceramics.

[0023] As an implementation method, in S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h under a nitrogen atmosphere, then heated to 400-1000°C at a heating rate of 80-120°C / h, and finally heated to 1200-2200°C at a heating rate of 3-15°C / h, and sintered for 3-7h to obtain silicon carbide ceramics. In the process of controlling the heating rate, the first stage is heated to 180-220°C under 8-12°C / h. The slow heating rate can effectively reduce the stress concentration inside the green body and avoid crack formation caused by rapid heating. This stage is mainly to remove moisture and other volatile substances in the mixture and reduce the risk of bubbles during subsequent high-temperature sintering. In the second stage, the temperature is increased to 400-1000°C under 80-120°C / h. The heating rate is relatively high, but it is still controlled within a safe range to speed up the early stage of sintering and shorten the total sintering time. In this temperature range, the binder begins to decompose, preparing for further sintering of silicon carbide particles. The third stage is heated to 1200-2200℃ at 3-15℃ / h. The heating rate in this stage is low to ensure that the material can be sintered evenly at high temperature to prevent abnormal grain growth or other defects. At high temperature, silicon carbide grains begin to grow, and the appropriate heating rate helps to control the grain size and obtain the desired microstructure. Keeping the temperature at high temperature for a period of time can ensure that the entire green body can reach a consistent sintering state, improve the density and uniformity of the material, and also help to improve the internal microstructure of the material, and improve the mechanical properties and thermal stability of the final silicon carbide ceramic. By gradually increasing the temperature and controlling the heating rate of each stage, the physical and chemical changes of the material during the sintering process can be effectively managed to avoid defects caused by too rapid temperature changes. The result is a silicon carbide ceramic with good density, uniform microstructure and excellent mechanical properties. At the same time, a reasonable holding time also helps to ensure uniform sintering inside the material and improve the quality and consistency of silicon carbide ceramics.

[0024] As an implementation method, in S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h in a nitrogen atmosphere, then heated to 750-850°C at a heating rate of 80-120°C / h, and finally heated to 1400-1600°C at a heating rate of 3-15°C / h, and sintered for 3-7h to obtain silicon carbide ceramics. In the second stage, the temperature is raised to 750-850°C under the condition of 80-120°C / h, at which time the binder will be completely decomposed. Compared with the range of 400-1000°C, 750-850°C is closer to the complete temperature of binder decomposition, which can more thoroughly remove the organic binder and reduce the impact of residual substances on the subsequent sintering process. And at 750-850°C, the grain boundaries between silicon carbide particles begin to become active, which helps the movement and rearrangement of the grain boundaries, forming a denser structure, which can improve the density of the material and reduce internal defects. In the third stage, the temperature is raised to 1400-1600℃ at 3-15℃ / h. Compared with the range of 1200-2200℃, 1400-1600℃ can better control the growth of silicon carbide grains and avoid the degradation of material properties caused by excessive grain size. In the temperature range of 1400-1600℃, the growth of silicon carbide grains is more uniform, which helps to form a denser microstructure, thereby improving the overall density and mechanical properties of the material.

[0025] At 1400-1600℃, the pores and defects inside the material are more easily eliminated because at this temperature, the grains are more tightly bonded and the material is denser, thus reducing the presence of pores and cracks. By setting the temperature rise range in the second stage at 750-850℃, it is possible to ensure that the binder is completely decomposed, while promoting grain boundary movement and optimizing the material structure. In the third stage, controlling the temperature at 1400-1600℃ can better control grain growth, increase the density of the material, and reduce internal defects. This more sophisticated temperature control scheme helps to obtain silicon carbide ceramic products with superior performance and more uniform structure.

[0026] As an embodiment, S3 further includes a preheating step before injection molding the mixed material into a sheet material, the preheating temperature is 50-100° C., and the preheating time is 10-30 minutes.

[0027] The present invention discloses an application of silicon carbide ceramics, including the silicon carbide ceramics prepared by any of the above-mentioned methods for preparing silicon carbide ceramics, including the application of silicon carbide ceramics in the fields of mechanical engineering, aerospace, automobile manufacturing, chemical industry, metallurgy, electronic packaging and environmental protection.

[0028] Example

[0029] Example 1: According to the percentage by mass, weigh the following raw materials: 70% silicon carbide, 5% oxidized polyethylene, 10% polypropylene, 0.5% aluminum powder, 12% talcum powder, and 2.5% silicon dioxide. The median particle size of silicon carbide is 10μm-30μm. The median particle size of talcum powder is 10μm-20μm. The particle size of silicon dioxide is 5μm-10μm. Add the above powders into a ball mill, mix them by ball milling at a speed of 160r / min for 24h to obtain a mixture. Then, use an injection molding machine to inject into a sheet material, and put the sheet material on a 200T hydraulic press for compaction. In a nitrogen atmosphere, the green body was heated to 200°C at a rate of 10°C / h, then to 600°C at a rate of 100°C / h, and then to 1300°C at a rate of 5°C / h, and sintered for 4 hours to obtain silicon carbide ceramics.

[0030] Example 2: According to the percentage by mass, the following raw materials are weighed: 73.5% silicon carbide, 12% polypropylene, 0.5% magnesium powder, 10% potassium feldspar powder, and 4% zinc oxide. The median particle size of silicon carbide is 20μm-50μm. The median particle size of potassium feldspar is 20μm-30μm. The particle size of zinc oxide is 5μm-10μm. The above powders are added to a ball mill and mixed by ball milling at a speed of 200r / min for 36h to obtain a mixture. Then, the sheet material is injected into an injection molding machine, and the sheet material is pressed on a 300T hydraulic press for densification. In a nitrogen atmosphere, the green body is heated to 200°C at a rate of 10°C / h, then heated to 800°C at a rate of 100°C / h, and heated to 1500°C at a rate of 10°C / h, and sintered for 5h to obtain silicon carbide ceramics.

[0031] Comparative Example 1:

[0032] The difference from Example 1 is that the raw materials are not mixed in a ball mill, but are mixed in a high-speed mixer for 24 hours to obtain a mixture. The rest is the same as Example 1.

[0033] Comparative Example 2:

[0034] The difference from Example 1 is that the sheet material is not placed on a hydraulic press for compaction, and the rest is the same as Example 1.

[0035] Comparative Example 3:

[0036] The following raw materials are weighed according to mass percentage: 85% silicon carbide, 5% polypropylene, 7.5% talcum powder, and 2.5% silicon dioxide, and silicon carbide ceramics are obtained through mixing, molding, drying, and sintering.

[0037] Application Example 1: The silicon carbide ceramic of Example 1 is placed in a glass column with a sand core and used to filter dye wastewater. At a flow rate of 100 mL / min, the dye removal rate reaches 99.3%.

[0038] Application Example 2: The silicon carbide ceramic obtained in Example 2 is used to prepare aluminum silicon carbide. Aluminum liquid is injected into a pressure infiltration furnace and then cooled to obtain an aluminum silicon carbide heat sink. The bending strength of the aluminum silicon carbide heat sink is 302 MPa, the elastic modulus is 211 GPa, the thermal conductivity is 213 W / m·K, and the linear expansion coefficient is 7.91±0.5 (10 -6 @25C).

[0039] Performance Test:

[0040] 1 Density: The density of silicon carbide ceramics is tested using the density test method in ASTM C373 Standard Test Method for Density of Ceramic Materials.

[0041] 2 Porosity: The porosity of silicon carbide ceramics is tested using the porosity test method in the ASTM C20 standard "Test Method for Determination of Microscopic Porosity of Ceramic Materials".

[0042] 3 Impact strength: The impact strength test method in ASTM C799 "Standard Test Method for Impact Strength of Ceramic Materials" is used to test the impact strength of silicon carbide ceramics.

[0043] Test results:

[0044] The test results are shown in Table 1 below.

[0045]

[0046] Table 1

[0047] Result analysis: Through the fine process control of Examples 1 and 2, including ball milling, high pressure pressing and precise sintering temperature control, the prepared silicon carbide ceramics have higher density, lower porosity and better impact strength than Comparative Examples 1-3. While Example 2 uses higher hydraulic pressure and higher processing temperature. Within the appropriate processing pressure and processing temperature range, as the processing pressure increases and the processing temperature increases, the prepared silicon carbide ceramics have higher density, lower porosity and better impact strength. While Comparative Example 1 does not use ball mill mixing, Comparative Example 2 does not perform hydraulic press densification. Due to the lack of key steps and control conditions, the preparation method of Comparative Examples 1-2 leads to the fact that the density, porosity and impact strength of the silicon carbide ceramics in Comparative Examples 1-2 are not as good as the silicon carbide ceramics in the materials in Examples 1-2. It can be seen that ball mill mixing has a greater impact on the performance of silicon carbide ceramics. Comparative Example 3 is a common method for preparing silicon carbide ceramics, and the density, porosity and impact strength of the prepared silicon carbide ceramics are significantly lower than the performance of the silicon carbide ceramics prepared by the preparation method of the present invention in Comparative Example 1. It can be seen from Examples 1 and 2 that the performance of the silicon carbide ceramics prepared by the present invention is relatively uniform. In summary, the silicon carbide ceramics prepared by the present invention are significantly better than the silicon carbide ceramics prepared by the traditional method in terms of performance. The preparation method of the present application can significantly improve the density, porosity and mechanical properties of silicon carbide ceramics, and the performance of the silicon carbide ceramics prepared by the present invention is relatively uniform. No pollutants such as waste gas and wastewater are generated during the preparation process of the present invention, and the impact on the environment is relatively small.

[0048] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for preparing silicon carbide ceramics, characterized in that: include: S1: weigh by weight: 70-90% silicon carbide, 5-15% binder, 2-5% recrystallization aid, 0.5-1% deoxidizer and 5-10% filler; S2: ball milling the raw materials to obtain a mixed material; S3: injection molding the mixed material into a sheet material; S4: pressing the sheet material to obtain a green body; S5: heating, heat preservation and sintering the green body in an inert atmosphere to finally obtain silicon carbide ceramics.

2. A method for preparing silicon carbide ceramic according to claim 1, characterized in that: The adhesive is selected from one of polyester polyol, polyethylene glycol, oxidized polyethylene or polypropylene, or a mixture of two thereof; The filler is selected from at least one of talc, potassium feldspar or sodium feldspar; The deoxidizer is selected from at least one of aluminum powder, copper powder, iron powder or magnesium powder; The recrystallization aid is selected from at least one of silicon dioxide, zinc oxide or titanium dioxide.

3. A method for preparing silicon carbide ceramics according to claim 2, characterized in that: The particle size of silicon carbide is 5-55μm; The particle size of the filler is 5-40 μm; The particle size of the recrystallization aid is 5-15 μm.

4. A method for preparing silicon carbide ceramic according to claim 1, characterized in that: The ball milling process in S2 uses a ball mill, and the speed of the ball mill is set to 150-220r / min, and the ball milling time is 20-40h; In S3, the mixed material is injection molded into a sheet material using an injection molding machine; In S4, the sheet material is pressed by a hydraulic press, and the pressure of the hydraulic press is set to 100-1000T.

5. The method for preparing silicon carbide ceramic according to claim 1, characterized in that: In S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h, heated to 400-1000°C at a heating rate of 80-120°C / h, heated to 1200-2200°C at a heating rate of 3-15°C / h under a nitrogen atmosphere, and sintered for 3-7h to obtain silicon carbide ceramics.

6. A method for preparing silicon carbide ceramics according to claim 5, characterized in that: In S5, the green body is heated to 180-220°C at a heating rate of 8-12°C / h, heated to 750-850°C at a heating rate of 80-120°C / h, heated to 1400-1600°C at a heating rate of 3-15°C / h under a nitrogen atmosphere, and sintered for 3-7h to obtain silicon carbide ceramics.

7. A method for preparing silicon carbide ceramics according to claim 1, characterized in that: S3 also includes a preheating step before injection molding the mixed material into a sheet material, the preheating temperature is 50-100° C., and the preheating time is 10-30 minutes.

8. An application of silicon carbide ceramics, wherein the silicon carbide ceramics are prepared by the method for preparing the silicon carbide ceramics as claimed in any one of claims 1 to 7, characterized in that: include: Silicon carbide ceramics are used in mechanical engineering, aerospace, automobile manufacturing, chemical industry, metallurgy, electronic packaging and environmental protection.

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