Composite sintering aid for silicon carbide honeycomb ceramics and method for preparing silicon carbide honeycomb ceramics

Abstract

The present application relates to the technical field of silicon carbide honeycomb ceramics, in particular to a composite sintering aid for silicon carbide honeycomb ceramics and a preparation method of silicon carbide honeycomb ceramics.The composite sintering aid comprises an active component and water, and the active component comprises sodium tetraborate, active alumina and strontium carbonate, and the mass fraction ratio is 0.3-0.6:0.5-1.0:0.5-1.0.The scheme effectively reduces the damage of the sintering aid to the material performance while retaining the excellent material performance of the silicon carbide porous material, further optimizes the strength and toughness of the material, further enhances and toughens the silicon carbide material, greatly reduces the shrinkage, reduces the sintering temperature, reduces the sintering deformation, improves the qualified rate, and makes the silicon carbide porous ceramic suitable for multiple fields.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide honeycomb ceramics technology, and more specifically, to composite sintering aids for silicon carbide honeycomb ceramics and methods for preparing silicon carbide honeycomb ceramics. Background Technology

[0002] Silicon carbide, as a high-performance third-generation semiconductor and advanced ceramic material, is reshaping and driving the development of numerous high-tech industries due to its core advantages such as high pressure resistance, high temperature resistance, high frequency and high efficiency, high thermal conductivity, and stable physicochemical properties. Simultaneously, its advantages in high temperature resistance and corrosion resistance make it outstanding in the field of high-temperature, corrosive, and demanding fluid purification, with wide applications in areas such as molten metal filtration, high-temperature gas filtration, and industrial wastewater treatment. Therefore, technological breakthroughs in the sintering process for silicon carbide filter materials are particularly crucial.

[0003] Currently, high-quality silicon carbide porous ceramics on the market face challenges such as difficult sintering and complex preparation processes, resulting in high costs. Furthermore, existing single sintering aids, while promoting silicon carbide sintering, often significantly reduce porosity while increasing strength, introducing undesirable impurities and making it difficult to achieve a synergistic effect of high porosity and high strength. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a composite sintering aid for silicon carbide honeycomb ceramics and a method for preparing silicon carbide honeycomb ceramics.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides a composite sintering aid for silicon carbide honeycomb ceramics, wherein the active components of the composite sintering aid include sodium tetraborate, activated alumina, and strontium carbonate in a mass ratio of 0.3-0.6:0.5-1.0:0.5-1.0.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the composite sintering aid also includes water, and the mass ratio of the active ingredient to water is 1.3-1.6:33.

[0008] The present invention also provides a silicon carbide honeycomb ceramic, wherein the raw materials of the silicon carbide honeycomb ceramic include inorganic solid components, pore-forming agents, and organic binders, wherein the inorganic solid components include metallic silicon powder; the raw materials of the silicon carbide honeycomb ceramic also include the composite sintering aids as described above.

[0009] Furthermore, based on the total mass of the inorganic solid components being 100%, the mass percentage of the active ingredient in the composite sintering aid is 1-3%.

[0010] Furthermore, the composition and mass percentage of the inorganic solid component are as follows: 80% silicon carbide micro powder and 20% metallic silicon powder; the particle size of the silicon carbide micro powder is 56-58 μm, and the particle size of the metallic silicon powder is 10-20 μm.

[0011] Furthermore, the pore-forming agent is a starch-based pore-forming agent or a resin-based pore-forming agent, and its mass is 45%-50% of the inorganic solid component.

[0012] Furthermore, the organic binder is one or more of methylcellulose, PVA, PET, etc., and its mass is 9%-10% of the inorganic solid component.

[0013] The present invention also provides a method for preparing silicon carbide honeycomb ceramic as described above, wherein the raw material of the silicon carbide honeycomb ceramic is prepared into a green body, and the silicon carbide honeycomb ceramic is obtained after sintering.

[0014] Furthermore, the sintering environment is an oxidizing atmosphere, the temperature is 1100℃-1200℃, and the time is 3.5-4.5 hours.

[0015] Furthermore, the specific process of preparing the raw material of the silicon carbide honeycomb ceramic into a green body is as follows: after mixing the components in the raw material, kneading and rolling to obtain clay segments, and then extruding the clay segments into a honeycomb structure to obtain the green body; before sintering, the green body is microwaved and dried.

[0016] The beneficial effects of this invention are as follows: (1) The composite sintering aid for silicon carbide honeycomb ceramics of the present invention achieves the strengthening and toughening effect by introducing newly generated silicon carbide whiskers and needle-like or plate-like strontium feldspar second phase, and can also significantly reduce the sintering temperature of silicon carbide honeycomb ceramics, while effectively controlling the decrease in porosity. (2) The silicon carbide honeycomb ceramic of the present invention, by adding composite sintering aids, effectively optimizes the antioxidant properties, and improves the sintering shrinkage and deformation, thereby greatly improving the product dimensional accuracy and pass rate; (3) The silicon carbide honeycomb ceramic of the present invention can maintain the high temperature stability of the material by adding composite sintering aid. Attached Figure Description

[0017] Figure 1 This is a SEM image of SiC whiskers in the microstructure of silicon carbide honeycomb ceramic in Embodiment 1 of the present invention; Figure 2 This is a SEM image of the porous wall structure of silicon carbide honeycomb ceramic in Embodiment 1 of the present invention. Detailed Implementation

[0018] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0019] The composite sintering aid for silicon carbide honeycomb ceramics of the present invention comprises sodium tetraborate, activated alumina, and strontium carbonate in a mass ratio of 0.3-0.6:0.5-1.0:0.5-1.0.

[0020] While single sintering aids or simple oxide mixtures can reduce sintering temperature to some extent, they generally suffer from problems such as uneven dispersion of the aids, differences in the bonding strength of the components leading to brittle fracture, and excessive sintering shrinkage causing product deformation. These issues make it difficult to achieve the innovative combination of high porosity, high strength, and low sintering shrinkage as described in this invention. The composite sintering aid for silicon carbide honeycomb ceramics of this invention allows the metallic silicon (powder) in the raw materials of the silicon carbide honeycomb ceramics to fully react with the carbon source in the composite aid to generate silicon carbide whiskers, which can toughen the material and facilitate the coating of reaction catalysts into the silicon carbide honeycomb ceramics, achieving a thorough filtration of automobile exhaust. Simultaneously, the aforementioned composite sintering aid can significantly reduce the sintering temperature of silicon carbide ceramics and introduces needle-like or plate-like strontium feldspar, further enhancing the strength and toughness of the silicon carbide material. During the preparation process, this composite sintering aid is introduced via solution impregnation, and the reduction in porosity of the silicon carbide honeycomb ceramics can be controlled to within 5%.

[0021] Based on the above principle, in other applications of silicon carbide porous ceramics used for filtering molten metal or industrial wastewater, a small amount of metallic silicon can be introduced according to the relative molecular mass ratio of metallic silicon to strontium carbonate. This can also ensure that metallic silicon and carbon react fully during the sintering process and achieve the same effect.

[0022] Preferably, the composite additive also includes water, and the mass ratio of active ingredient to water is 1.3-1.6:33.

[0023] The silicon carbide honeycomb ceramic of the present invention comprises inorganic solid components, pore-forming agents, and organic binders in its raw materials. The inorganic solid components include silicon carbide micro powder and metallic silicon powder. The raw materials of the silicon carbide honeycomb ceramic also include the above-mentioned composite sintering aids.

[0024] The silicon carbide honeycomb ceramic of this invention has high porosity. In an oxidation resistance test conducted at 1500°C for 100 hours, the silicon carbide honeycomb ceramic exhibited superior oxidation resistance compared to silicon carbide filters sintered under an inert gas protective atmosphere. The degree of oxidation of the product can be characterized by the weight change of the silicon carbide honeycomb ceramic during the heat preservation process. Furthermore, a softening temperature test showed that this silicon carbide honeycomb ceramic has a softening temperature greater than 1780°C, fully meeting the requirements for operating environments ranging from 1100-1500°C.

[0025] Preferably, the mass percentage of active ingredients in the composite sintering aid is 1-3%, based on the total mass of inorganic solid components being 100%.

[0026] More preferably, when using the composite sintering aid, it needs to be prepared as an aqueous solution. After preparing the aqueous solution of the composite sintering aid according to the above ratio, the addition of the aqueous solution simultaneously meets the content requirements of the above active ingredients.

[0027] Preferably, the composition and mass percentage of the inorganic solid component are: 80% silicon carbide micro powder and 20% metallic silicon powder; the particle size of the silicon carbide micro powder is 56-58 μm and the particle size of the metallic silicon powder is 10-20 μm.

[0028] Preferably, the pore-forming agent is a starch-based pore-forming agent or a resin-based pore-forming agent, and its mass is 45%-50% of the inorganic solid component.

[0029] Preferably, the pore-forming agent is nylon resin.

[0030] Preferably, the organic binder is one or more of methylcellulose, PVA, PET, etc., and its mass is 9%-10% of the inorganic solid component.

[0031] The method for preparing silicon carbide honeycomb ceramics of the present invention involves preparing the raw materials of silicon carbide honeycomb ceramics into green blanks, and then sintering them to obtain silicon carbide honeycomb ceramics.

[0032] Preferably, the sintering environment is an oxidizing atmosphere, the temperature is 1100℃-1200℃, and the time is 3.5-4.5 hours.

[0033] Preferably, the specific process for preparing the raw materials of silicon carbide honeycomb ceramic into green bodies is as follows: after mixing the components in the raw materials, kneading and rolling them to obtain clay segments, and then extruding the clay segments into a honeycomb structure to obtain green bodies; before sintering, the green bodies are microwaved and dried.

[0034] Specifically, the preparation method of the present invention includes the following steps: S1. Silicon carbide micro powder and metallic silicon powder are mixed using a dry method. A pore-forming agent and an organic binder are added to the inorganic components to obtain the mixed powder.

[0035] S2. Use a glass rod to mix all the components of the composite sintering aid evenly in a clean small bucket to obtain the composite sintering aid.

[0036] S3. Place the mixed powder obtained in step S1 into a kneading machine, add the composite sintering aid and knead for 7 minutes, then add the molding aid and knead for 10 minutes to obtain the clay.

[0037] Since the composite sintering aid of the present invention contains water, the composite sintering aid is added by solution impregnation.

[0038] The amount of molding aid added is based on the total mixture components, and the amount added is 3%. The purpose is to increase the plasticity, lubricity and surface activity of the clay. Organic additives such as soybean oil, butter, and surfactants can be used.

[0039] Preferably, the molding aid is a mixture of potassium laurate and butter in a mass ratio of 1:1.

[0040] S4. Refining the clay obtained from S3 yields shaped clay segments, which are then sliced ​​into sections.

[0041] S5. Extrude the plastic clay segments into a honeycomb structure green body, and then microwave and dry it.

[0042] S6. After the dried blank is cut into fixed heights, it is sintered.

[0043] The silicon carbide porous ceramics prepared using the composite sintering aid of this invention are not limited to gas filtration materials. The same mechanism of action also applies to the sintering process of silicon carbide porous filters or filter sheets used in molten metal filtration and industrial wastewater filtration. This allows for the preservation of the excellent material properties of porous silicon carbide while reducing the destructive effects of the sintering aid on material properties, further optimizing the material's strength and toughness. Its advantages lie in retaining the excellent performance of silicon carbide filters, further strengthening and toughening the silicon carbide material, significantly reducing shrinkage, lowering the sintering temperature, minimizing sintering deformation, and improving the yield rate.

[0044] The present invention will be illustrated by specific embodiments below.

[0045] Example 1 This embodiment uses the method of the present invention to prepare silicon carbide honeycomb ceramics, and the specific steps are as follows: S1. A dry mixing process is used to combine 80% by weight of 56-58μm silicon carbide micro powder and 20% by weight of 10-20μm metallic silicon powder. A pore-forming agent and an organic binder are then added to the inorganic components to obtain the mixed powder.

[0046] In this embodiment, the pore-forming agent has a mass percentage of 48%, and the organic binder has a mass percentage of 9.5%; the pore-forming agent is nylon resin, and the organic binder is hydroxypropyl methylcellulose.

[0047] S2. Use a glass rod to mix all the components of the composite sintering aid evenly in a clean small bucket to obtain the composite sintering aid.

[0048] In this embodiment, the composite sintering aid contains the following components and their mass percentages: 0.3% sodium tetraborate (Na2B4O7), 0.5% activated alumina (Al2O3), 0.5% strontium carbonate (SrCO3), and 33% water. The above percentages are based on an inorganic solid component of 100%.

[0049] S3. Place the mixed powder obtained in step S1 into a kneading machine. Add 20% of the composite sintering aid, which is an aqueous solution containing the above-mentioned components, based on 100% of the mass of the mixed powder. Knead for 7 minutes, then add 3% of the molding aid by weight of the kneaded mixture and knead for another 10 minutes to obtain clay.

[0050] The molding aid in this embodiment is a mixture of potassium laurate and butter, with a mass ratio of 1:1.

[0051] S4. The clay obtained from S3 is processed to obtain shaped clay segments, which are then sliced ​​three times to form segments.

[0052] S5. Extrude the plastic clay segments into a honeycomb structure green body with an extrusion size of 40×40×177.8mm including the outer skin, and then microwave and dry it.

[0053] S6. After the dried blank is cut into a fixed height, it is sintered at a high temperature of 1150℃ in an oxidizing atmosphere.

[0054] In this embodiment, the silicon carbide honeycomb ceramic is specifically a wall-flow honeycomb ceramic filter. The SEM image of the SiC whiskers that enhance and toughen the surface microstructure is shown below. Figure 1 As shown, its porous wall structure SEM image is as follows. Figure 2 As shown.

[0055] Example 2 This embodiment uses the method of the present invention to prepare silicon carbide honeycomb ceramics, and the specific steps are as follows: S1. A dry mixing process is used to combine 80% by weight of 56-58μm silicon carbide micro powder and 20% by weight of 10-20μm metallic silicon powder. A pore-forming agent and an organic binder are then added to the inorganic components to obtain the mixed powder.

[0056] In this embodiment, the pore-forming agent has a mass percentage of 48%, and the organic binder has a mass percentage of 9.5%; the pore-forming agent is nylon resin, and the organic binder is hydroxypropyl methylcellulose.

[0057] S2. Use a glass rod to mix all the components of the composite sintering aid evenly in a clean small bucket to obtain the composite sintering aid.

[0058] In this embodiment, the composite sintering aid contains the following components and their mass percentages: 0.6% sodium tetraborate (Na2B4O7), 0.5% activated alumina (Al2O3), 0.5% strontium carbonate (SrCO3), and 33% water. The above percentages are based on an inorganic solid component of 100%.

[0059] S3. Place the mixed powder obtained in step S1 into a kneading machine. Add 20% of the composite sintering aid, which is an aqueous solution containing the above-mentioned components, based on 100% of the mass of the mixed powder. Knead for 7 minutes, then add 3% of the molding aid by weight of the kneaded mixture and knead for another 10 minutes to obtain clay.

[0060] The molding aid in this embodiment is a mixture of potassium laurate and butter, with a mass ratio of 1:1.

[0061] S4. The clay obtained from S3 is processed to obtain shaped clay segments, which are then sliced ​​three times to form segments.

[0062] S5. Extrude the plastic clay segments into a honeycomb structure green body with an extrusion size of 40×40×177.8mm including the outer skin, and then microwave and dry it.

[0063] S6. After the dried blank is cut into a fixed height, it is sintered at a high temperature of 1150℃ in an oxidizing atmosphere.

[0064] Example 3 This embodiment uses the method of the present invention to prepare silicon carbide honeycomb ceramics, and the specific steps are as follows: S1. A dry mixing process is used to combine 80% by weight of 56-58μm silicon carbide micro powder and 20% by weight of 10-20μm metallic silicon powder. A pore-forming agent and an organic binder are then added to the inorganic components to obtain the mixed powder.

[0065] In this embodiment, the pore-forming agent has a mass percentage of 48%, and the organic binder has a mass percentage of 9.5%; the pore-forming agent is nylon resin, and the organic binder is hydroxypropyl methylcellulose.

[0066] S2. Use a glass rod to mix all the components of the composite sintering aid evenly in a clean small bucket to obtain the composite sintering aid.

[0067] In this embodiment, the composite sintering aid contains the following components and their mass percentages: 0.6% sodium tetraborate (Na2B4O7), 1% activated alumina (Al2O3), 0.5% strontium carbonate (SrCO3), and 33% water. The above percentages are based on an inorganic solid component of 100%.

[0068] S3. Place the mixed powder obtained in step S1 into a kneading machine. Add 20% of the composite sintering aid, which is an aqueous solution containing the above-mentioned components, based on 100% of the mass of the mixed powder. Knead for 7 minutes, then add 3% of the molding aid by weight of the kneaded mixture and knead for another 10 minutes to obtain clay.

[0069] The molding aid in this embodiment is a mixture of potassium laurate and butter, with a mass ratio of 1:1.

[0070] S4. The clay obtained from S3 is processed to obtain shaped clay segments, which are then sliced ​​three times to form segments.

[0071] S5. Extrude the plastic clay segments into a honeycomb structure green body with an extrusion size of 40×40×177.8mm including the outer skin, and then microwave and dry it.

[0072] S6. After the dried blank is cut into a fixed height, it is sintered at a high temperature of 1150℃ in an oxidizing atmosphere.

[0073] Example 4 This embodiment uses the method of the present invention to prepare silicon carbide honeycomb ceramics, and the specific steps are as follows: S1. A dry mixing process is used to combine 80% by weight of 56-58μm silicon carbide micro powder and 20% by weight of 10-20μm metallic silicon powder. A pore-forming agent and an organic binder are then added to the inorganic components to obtain the mixed powder.

[0074] In this embodiment, the pore-forming agent has a mass percentage of 48%, and the organic binder has a mass percentage of 9.5%; the pore-forming agent is nylon resin, and the organic binder is hydroxypropyl methylcellulose.

[0075] S2. Use a glass rod to mix all the components of the composite sintering aid evenly in a clean small bucket to obtain the composite sintering aid.

[0076] In this embodiment, the composite sintering aid contains the following components and their mass percentages: 0.6% sodium tetraborate (Na2B4O7), 0.5% activated alumina (Al2O3), 1% strontium carbonate (SrCO3), and 33% water. The above percentages are based on an inorganic solid component of 100%.

[0077] S3. Place the mixed powder obtained in step S1 into a kneading machine. Add 20% of the composite sintering aid, which is an aqueous solution containing the above-mentioned components, based on 100% of the mass of the mixed powder. Knead for 7 minutes, then add 3% of the molding aid by weight of the kneaded mixture and knead for another 10 minutes to obtain clay.

[0078] The molding aid in this embodiment is a mixture of potassium laurate and butter, with a mass ratio of 1:1.

[0079] S4. The clay obtained from S3 is processed to obtain shaped clay segments, which are then sliced ​​three times to form segments.

[0080] S5. Extrude the plastic clay segments into a honeycomb structure green body with an extrusion size of 40×40×177.8mm including the outer skin, and then microwave and dry it.

[0081] S6. After the dried blank is cut into a fixed height, it is sintered at a high temperature of 1150℃ in an oxidizing atmosphere.

[0082] Comparative Example 1 The only difference between this comparative example and Example 1 is that the components and their mass percentages in the composite sintering aid are: 0.5% by mass of activated alumina (Al2O3), 0.5% by mass of strontium carbonate (SrCO3), and 33% water. Furthermore, the sintering temperature is 1400°C.

[0083] Comparative Example 2 The only difference between this comparative example and Example 1 is that no composite sintering aid is used, and only 20% water is added for the first kneading.

[0084] Comparative Example 3 The only difference between this comparative example and Example 1 is that no composite sintering aid was used; only 20% water was added for the first kneading. Furthermore, the sintering temperature was 1400°C.

[0085] Comparative Example 4 The only difference between this comparative example and Example 1 is that the components and their mass percentages in the composite sintering aid are: 1.5% sodium tetraborate (Na2B4O7), 0.5% activated alumina (Al2O3), 0.5% strontium carbonate (SrCO3), and 33% water.

[0086] Comparative Example 5 The only difference between this comparative example and Example 1 is that the components and their mass percentages in the composite sintering aid are: 1.5% sodium tetraborate (Na2B4O7), 1% activated alumina (Al2O3), and 33% water.

[0087] Comparative Example 6 The only difference between this comparative example and Example 1 is that the components and their mass percentages in the composite sintering aid are: 0.6% sodium tetraborate (Na2B4O7), 1% strontium carbonate (SrCO3), and 33% water.

[0088] To compare the pressure drop of the embodiments, the honeycomb ceramics prepared in the above embodiments and comparative examples have specific specifications of 304.8 mm in diameter, 254 mm in height, 300 cpsi in pore density, and 9 mil in wall thickness. However, the diameter, height, pore density, and wall thickness of the present invention are not limited to these, nor are the shape and application fields of the material. For example, silicon carbide honeycomb ceramics are not limited to automobile exhaust treatment, but are also suitable for industrial wastewater, molten metal filtration, and other fields.

[0089] The performance of the honeycomb ceramics obtained in the above embodiments and comparative examples was tested, and the test results are shown in Table 1. Table 1 Test results for each embodiment and comparative example Comparing Example 1 and Comparative Example 1, it can be seen that sodium tetraborate in the composite sintering aid effectively reduces the sintering temperature of the product, while maintaining similar material properties, thus achieving effective energy saving.

[0090] The test results of Comparative Examples 2 and 3 show that without the use of composite sintering aids, the material properties need to exceed 1400℃ to achieve the same level. Current experiments have shown that the compressive strength of the material is still below 10MPa when sintered at 1400℃. This indicates that the composite aids effectively reduce the sintering temperature and improve the strength and oxidation resistance of the material. At the same time, it reduces the sintering shrinkage of the product and reduces the deformation of the product, which can effectively improve the product qualification rate.

[0091] The test results of Examples 2-4 show that in the composite sintering aid system of the present invention, the mass ratio of sodium tetraborate, alumina and strontium carbonate can fluctuate within an appropriate range, and the material properties are similar. This indicates that the scope of protection of the present invention should include the content of substances with different mass ratios, and no specific requirements are made on the mass ratio of the substances.

[0092] The test results of Comparative Examples 1, 2-3, and 5-6 show that when one or more of the three composite sintering aids are removed, the performance of the honeycomb ceramic is significantly affected, the sintering temperature of the material is greatly affected, or the material performance is adversely affected. Therefore, the composite aid of the present invention can achieve an effective synergistic effect of the three components.

[0093] Therefore, the test results of Examples 1-4 demonstrate that the present invention, by using a suitable mass ratio of composite sintering aid, reduces the sintering temperature and shrinkage during the sintering process, resulting in a diesel vehicle filter with an A-axis compressive strength >10MPa, a shrinkage ratio <1.5%, a porosity >60%, and a median pore size of 20-22μm. Furthermore, the material's high-temperature softening temperature and oxidation resistance are superior to products without the composite sintering aid.

[0094] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite sintering aid for silicon carbide honeycomb ceramics, characterized in that, The active components of the composite sintering aid include sodium tetraborate, activated alumina, and strontium carbonate, in a mass ratio of 0.3-0.6:0.5-1.0:0.5-1.

0.

2. The composite sintering aid for silicon carbide honeycomb ceramics according to claim 1, characterized in that, The composite sintering aid also includes water, and the mass ratio of the active ingredient to water is 1.3-1.6:

33.

3. A silicon carbide honeycomb ceramic, characterized in that, The raw materials of the silicon carbide honeycomb ceramic include inorganic solid components, pore-forming agents, and organic binders, wherein the inorganic solid components include metallic silicon powder; the raw materials of the silicon carbide honeycomb ceramic also include the composite sintering aid as described in claim 1 or 2.

4. A silicon carbide honeycomb ceramic according to claim 3, characterized in that, Based on the total mass of the inorganic solid components being 100%, the mass percentage of the active ingredient in the composite sintering aid is 1-3%.

5. A silicon carbide honeycomb ceramic according to claim 3, characterized in that, The composition and mass percentage of the inorganic solid component are as follows: 80% silicon carbide micro powder and 20% metallic silicon powder; the particle size of the silicon carbide micro powder is 56-58 μm and the particle size of the metallic silicon powder is 10-20 μm.

6. A silicon carbide honeycomb ceramic according to claim 3, characterized in that, The pore-forming agent is a starch-based pore-forming agent or a resin-based pore-forming agent, and its mass is 45%-50% of the inorganic solid component.

7. A silicon carbide honeycomb ceramic according to claim 3, characterized in that, The organic binder is one or more of methylcellulose, PVA, PET, etc., and its mass is 9%-10% of the inorganic solid component.

8. A method for preparing silicon carbide honeycomb ceramic as described in any one of claims 3-7, characterized in that, The raw materials for the silicon carbide honeycomb ceramic are prepared into green blanks, which are then sintered to obtain the silicon carbide honeycomb ceramic.

9. The method for preparing silicon carbide honeycomb ceramic according to claim 8, characterized in that, The sintering environment is an oxidizing atmosphere, the temperature is 1100℃-1200℃, and the time is 3.5-4.5 hours.

10. The method for preparing silicon carbide honeycomb ceramic according to claim 8, characterized in that, The specific process of preparing the raw material of the silicon carbide honeycomb ceramic into a green body is as follows: after mixing the components in the raw material, kneading and rolling to obtain clay segments, and then extruding the clay segments into a honeycomb structure to obtain the green body; before sintering, the green body is microwaved and dried.

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