A high solid content, low viscosity silicon carbide ceramic slurry, its preparation method and application
By combining aluminum salt modification with specific dispersants, a silicon carbide ceramic slurry with high solid content and low viscosity was prepared, which solved the problem of powder agglomeration and sedimentation, and achieved the stability and fluidity of silicon carbide ceramic molding, thereby improving molding quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2024-09-20
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies make it difficult to prepare silicon carbide ceramic slurries with high solid content and low viscosity, which leads to powder agglomeration and sedimentation during the slurry casting process, affecting the molding quality and efficiency.
Aluminum salt-modified α-SiC powder, along with tetramethylammonium hydroxide, ethylene glycol, and isopropanol as dispersants, was used to prepare silicon carbide ceramic slurry by mixing the dispersion. The hydrophilicity of the modified powder and the ionization effect of the dispersant were utilized to form a stable slurry system.
A stable silicon carbide ceramic slurry with high solid content (65 vol.% to 60 vol.%), low viscosity (0.2612 Pa·s to 1.2402 Pa·s) was obtained, ensuring the smooth progress of slip casting and the compactness of the formed green body.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of ceramic materials technology, specifically to a silicon carbide ceramic slurry with high solid content and low viscosity, its preparation method, and its application. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] Silicon carbide ceramics are novel high-temperature resistant ceramics with extremely strong covalent bonds, and have been widely used in high-tech fields in recent years. They can be used as linings for high-temperature furnaces, rocket combustion chambers, radar radomes, precision bearings, ceramic engines, nozzles, high-temperature gas turbine rotors, fuel units, heat exchange components, and nuclear reactor materials, among others.
[0004] Obtaining highly reliable silicon carbide materials is inseparable from their molding process. The molding processes for silicon carbide ceramic materials are mainly divided into two types: wet molding and dry molding. Dry molding includes dry pressing and isostatic pressing. Wet molding includes plastic forming and colloidal molding. Colloidal molding mainly includes slip casting, tape casting, and novel colloidal molding methods.
[0005] Slip casting is a near-net-shape forming technology. Its forming process is relatively simple, easy to control, highly efficient, and low-cost. It produces uniform silicon carbide ceramic blanks and can form geometrically complex, large-sized, porous tubular supports, as well as thin-walled blanks. The slip casting process for silicon carbide ceramics involves injecting a suitable amount of well-dispersed, water-soluble ceramic powder organic suspension into a plaster mold. The capillary force of the small pores within the plaster mold removes excess water from the slurry, causing it to solidify and adhere to the inner wall of the mold. After a certain period of drying and shrinkage, the formed blank gradually separates from the plaster mold, and is then removed from the mold.
[0006] The success of slip casting hinges on the preparation of the slurry, which requires high solids content (volume solids ≥ 50%), low viscosity (≤ 1 Pa·s), good fluidity, stability, uniformity, low thixotropy, and good permeability. Low viscosity facilitates smooth slip casting, while high solids content ensures a dense and high-strength green body. However, there is a trade-off between high solids content and low viscosity; high solids content can lead to agglomeration and sedimentation of the powder. Therefore, how to prepare a silicon carbide ceramic slurry with high solids content, low viscosity, and stable performance has become an urgent problem to be solved in the production of silicon carbide ceramic components. Summary of the Invention
[0007] To overcome the above problems, the present invention provides a silicon carbide ceramic slurry with high solid content and low viscosity, its preparation method and application.
[0008] To achieve the above technical objectives, the present invention adopts the following technical solution:
[0009] In a first aspect, the present invention provides a silicon carbide ceramic slurry with high solids content and low viscosity, the components of which include aluminum salt modified α-SiC powder and a dispersant, wherein the dispersant includes tetramethylammonium hydroxide, ethylene glycol and isopropanol.
[0010] A second aspect of the present invention provides a method for preparing the silicon carbide ceramic slurry described in the first aspect, comprising:
[0011] A mixed dispersion was obtained by mixing tetramethylammonium hydroxide, ethylene glycol, isopropanol and deionized water.
[0012] Aluminum salt-modified α-SiC powder was added to the mixed dispersion in batches and stirred to obtain silicon carbide ceramic slurry.
[0013] The beneficial effects of this invention are as follows:
[0014] (1) To improve the dispersion stability of α-SiC powder in water, it was first modified with Al(NO3)3. The modified α-SiC powder has better hydrophilicity, and the zeta potential of the modified α-SiC powder surface is negative. Tetramethylammonium hydroxide will ionize in water: The generated OH - Providing a strongly alkaline environment to the solution significantly increases the negative charge on the surface of the modified α-SiC powder, reduces the surface zeta potential, and prevents the agglomeration of the α-SiC powder. Simultaneously, ethylene glycol molecules contain two hydroxyl groups, and isopropanol molecules contain one hydroxyl group. These hydroxyl groups can form hydrogen bonds or van der Waals forces with the surface of the α-SiC powder, thereby adsorbing onto the surface of the α-SiC particles and creating steric hindrance to prevent powder aggregation and precipitation. Therefore, this invention can obtain a silicon carbide ceramic slurry with high solids content, low viscosity, and stable performance.
[0015] (2) The ceramic slurry prepared by the present invention has a viscosity of 0.2612 Pa·s to 1.2402 Pa·s at a solid content of 65 vol.% and a settling height of 1.5 mm to 4 mm after standing for 12 hours. It has good stability and meets the requirements of high solid content and low viscosity. Detailed Implementation
[0016] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0017] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0018] A first typical embodiment of the present invention provides a silicon carbide ceramic slurry with high solid content and low viscosity. The components of the silicon carbide ceramic slurry include: aluminum salt modified α-SiC powder and a dispersant, wherein the dispersant includes tetramethylammonium hydroxide, ethylene glycol and isopropanol.
[0019] In one or more embodiments, the mass ratio of aluminum salt modified α-SiC powder to tetramethylammonium hydroxide, ethylene glycol and isopropanol is 100:2:0 to 6.1:2.6, preferably 100:2:5.5:2.6.
[0020] In one or more embodiments, the preparation method of aluminum salt modified α-SiC powder includes: placing α-SiC powder and aluminum salt in deionized water, heating and stirring, and collecting the solid as aluminum salt modified α-SiC powder.
[0021] Preferably, the α-SiC powder comprises α-SiC powder with particle sizes of 0.5 μm, 2.5 μm, and 10 μm.
[0022] More preferably, the mass ratio of α-SiC powder with a particle size of 0.5 μm, α-SiC powder with a particle size of 2.5 μm, and α-SiC powder with a particle size of 10 μm is 2 to 7: 2 to 8: 1 to 7, preferably 5: 8: 7, 3: 4: 3, 7: 8: 5, and 2: 2: 1.
[0023] Preferably, the aluminum salt comprises Al(NO3)3.
[0024] More preferably, the mass ratio of α-SiC powder to Al(NO3)3 is 1:0.002 to 0.008.
[0025] Preferably, the heating and stirring temperature is 50–80°C, and the heating and stirring time is 3–6 hours.
[0026] Preferably, the method for collecting the solids includes centrifugation to remove the supernatant and then obtaining aluminum salt-modified α-SiC powder.
[0027] More preferably, the centrifugation rate is 3500–4500 r / min, and the centrifugation time is 5–10 min.
[0028] Preferably, aluminum salt modified α-SiC powder is obtained by collecting and drying the solid and passing it through an 80-100 mesh sieve.
[0029] A second typical embodiment of the present invention provides a method for preparing the silicon carbide ceramic slurry described in the first aspect, comprising:
[0030] A mixed dispersion was obtained by mixing tetramethylammonium hydroxide, ethylene glycol, isopropanol and deionized water.
[0031] Aluminum salt-modified α-SiC powder was added to the mixed dispersion in batches and stirred to obtain silicon carbide ceramic slurry.
[0032] In one or more embodiments, tetramethylammonium hydroxide, ethylene glycol, isopropanol and deionized water are stirred and mixed to obtain a mixed dispersion, wherein the stirring speed is 200-400 r / min and the stirring time is 10-15 min.
[0033] In one or more embodiments, aluminum salt-modified α-SiC powder is added to a mixed dispersion in batches, and when stirring to obtain silicon carbide ceramic slurry, the stirring speed is 100-400 r / min, and the stirring time is 16-24 h.
[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0035] Example 1
[0036] (1) Disperse 100g of α-SiC powder with a particle size of 0.5μm and 0.5g of Al(NO3)3 powder in 200mL of deionized water, and stir in a water bath at 60℃ at a stirring rate of 500r / min for 5h. Centrifuge the stirred α-SiC suspension in a high-speed centrifuge (4500r / min, 10min) to separate the supernatant, collect the solid, dry it in a forced-air drying oven at 50-80℃ and pass it through an 80-100 mesh sieve to obtain aluminum salt modified α-SiC powder (0.5μm).
[0037] (2) 100g of α-SiC powder with a particle size of 2.5μm and 0.5g of Al(NO3)3 powder were dispersed in 200mL of deionized water and stirred in a water bath at 60℃ at a stirring rate of 500r / min for 5h. The stirred α-SiC suspension was centrifuged in a high-speed centrifuge (4500r / min, 10min) to separate the supernatant. The solid was collected, dried in a forced-air drying oven at 50-80℃, and passed through an 80-100 mesh sieve to obtain aluminum salt modified α-SiC powder (2.5μm).
[0038] (3) Disperse 100g of α-SiC powder with a particle size of 10μm and 0.5g of Al(NO3)3 powder in 200mL of deionized water, and stir in a water bath at 60℃ at a stirring rate of 500r / min for 5h. Centrifuge the stirred α-SiC suspension at 4500r / min for 10min to separate the supernatant, collect the solid, dry it in a forced-air drying oven at 50-80℃ and pass it through an 80-100 mesh sieve to obtain aluminum salt modified α-SiC powder (10μm).
[0039] Example 2
[0040] Add 2.4 g of 25% tetramethylammonium hydroxide aqueous solution (water volume is 1.8 mL), 1.5 mL of ethylene glycol, 1 mL of isopropanol and 0.7 mL of deionized water to a beaker, stir evenly with a mechanical stirrer at a speed of 400 r / min for 15 min to obtain a mixed dispersion.
[0041] Example 3
[0042] The aluminum salt-modified α-SiC powders (0.5 μm, 2.5 μm, and 10 μm) prepared in Example 1 were weighed in a mass ratio of 5:8:7, totaling 30 g. The three modified α-SiC powders were mixed evenly and added in batches to the mixed dispersion prepared in Example 2. The batch additions were 10 g, 5 g, 4 g, 3 g, 2 g, 2 g, and 2 g respectively, with the remaining 2 g added in 10 separate batches. A mechanical stirrer was continuously operated at 300 r / min. During the batch addition of the salt-modified α-SiC powder, the viscosity of the slurry was monitored in real time to obtain the maximum solid content when the viscosity was less than 1.0 Pa·s. The slurry was then continuously stirred for 24 h.
[0043] In this embodiment, theoretically, 30g of aluminum salt-modified α-SiC powder is dissolved in 5mL of the mixed dispersion from Example 2 to obtain a ceramic slurry with a solid content of 65 vol.%. However, in actual addition, the state of the slurry changes or even fails to form a slurry as the mass of silicon carbide powder increases. Therefore, to maintain the stability of the slurry, solvents such as deionized water, ethylene glycol, or isopropanol are added to the slurry during preparation to maintain its properties. However, this reduces the solid content of the slurry due to the increase in liquid volume. Therefore, in this embodiment, 30g of silicon carbide powder is added completely, and the amount of solvent is supplemented during the slurry preparation process. Ultimately, this embodiment yields a slurry with a solid content of 55-60 vol.%, a viscosity of 0.5779-1.2401 Pa·s, and a silicon carbide slurry stability h / h0 = 4.902-5.387%. Stability refers to the ratio of the height h0 of the precipitated liquid to the original height h of the slurry after standing for 24 hours.
[0044] The slurry with a solid content of 55 vol.% was supplemented with 2.5 mL of deionized water during the pulping process, and its viscosity was 0.5779 Pa·s, with a stability of 4.902%. The slurry with a solid content of 60 vol.% was supplemented with 0.7 mL of ethylene glycol and 0.5 mL of isopropanol during the pulping process, and its corresponding viscosity was 1.2401 Pa·s, with a stability of 5.387%.
[0045] Formula for calculating solid content:
[0046]
[0047] Example 4
[0048] The aluminum salt-modified α-SiC powders (0.5 μm, 2.5 μm, and 10 μm) prepared in Example 1 were weighed in a mass ratio of 3:4:3, totaling 30 g. The three modified α-SiC powders were mixed evenly and added in batches to the mixed dispersion prepared in Example 2. The batch additions were 10 g, 5 g, 4 g, 3 g, 2 g, 2 g, and 2 g respectively, with the remaining 2 g added in 10 separate batches. A mechanical stirrer was continuously operated at 300 r / min. During the batch addition of the salt-modified α-SiC powder, the viscosity of the slurry was monitored in real time to obtain the maximum solid content when the viscosity was less than 1.0 Pa·s (meaning the powder was not completely used up during the addition process). The slurry was then continuously stirred for 24 h.
[0049] In this embodiment, theoretically, 30g of aluminum salt-modified α-SiC powder is dissolved in 5mL of the mixed dispersion from Example 2 to obtain a ceramic slurry with a solid content of 65 vol.%. However, in actual addition, the state of the slurry changes or even fails to form a slurry as the mass of silicon carbide powder increases. Therefore, to maintain the stability of the slurry, solvents such as deionized water, ethylene glycol, or isopropanol are added to the slurry during preparation to maintain its properties. However, this reduces the solid content of the slurry due to the increase in liquid volume. Therefore, in this embodiment, 30g of silicon carbide powder is completely added, and the amount of solvent is supplemented during the slurry preparation process. Ultimately, this embodiment can obtain a slurry with a solid content of 60-65 vol.%, a viscosity of 0.2612-0.3639 Pa·s, and a silicon carbide slurry stability h / h0 = 4.525-5.321%.
[0050] The slurry with a solid content of 60 vol.% was supplemented with 0.5 mL of ethylene glycol and 0.5 mL of isopropanol during the pulping process, and its viscosity was 0.2612 Pa·s and its stability was 4.525%; the slurry with a solid content of 65 vol.% had a viscosity of 0.3639 Pa·s and a stability of 5.321%.
[0051] Example 5
[0052] The aluminum salt-modified α-SiC powders (0.5 μm, 2.5 μm, and 10 μm) prepared in Example 1 were weighed in a mass ratio of 7:8:5, totaling 30 g. The three modified α-SiC powders were mixed evenly and added in batches to the mixed dispersion prepared in Example 2. The batch additions were 10 g, 5 g, 4 g, 3 g, 2 g, 2 g, and 2 g respectively, with the remaining 2 g added in 10 separate batches. A mechanical stirrer was continuously operated at 300 r / min. During the batch addition of the salt-modified α-SiC powder, the viscosity of the slurry was monitored in real time to obtain the maximum solid content when the viscosity was less than 1.0 Pa·s (meaning the powder was not completely used up during the addition process). The slurry was then continuously stirred for 24 h.
[0053] In this embodiment, theoretically, 30g of aluminum salt-modified α-SiC powder is dissolved in 5mL of the mixed dispersion from Example 2 to obtain a ceramic slurry with a solid content of 65 vol.%. However, in actual addition, the state of the slurry changes or even fails to form a slurry as the mass of silicon carbide powder increases. Therefore, to maintain the stability of the slurry, solvents such as deionized water, ethylene glycol, or isopropanol are added to the slurry during preparation to maintain its properties. However, this reduces the solid content of the slurry due to the increase in liquid volume. Therefore, in this embodiment, 30g of silicon carbide powder is completely added, and the amount of solvent is supplemented during the slurry preparation process. Ultimately, this embodiment can obtain a slurry with a solid content of 55-59 vol.%, a viscosity of 0.3997-0.4625 Pa·s, and a silicon carbide slurry stability h / h0 = 4.985-5.347%.
[0054] The slurry with a solid content of 55 vol.% was supplemented with 1.5 mL of ethylene glycol and 1 mL of isopropanol during the pulping process, and its viscosity was 0.3997 Pa·s, with a stability of 4.985%. The slurry with a solid content of 59 vol.% was supplemented with 0.6 mL of ethylene glycol and 0.7 mL of isopropanol during the pulping process, and its corresponding viscosity was 0.4625 Pa·s, with a stability of 5.347%.
[0055] Example 6
[0056] The aluminum salt-modified α-SiC powders (0.5 μm, 2.5 μm, and 10 μm) prepared in Example 1 were weighed in a mass ratio of 2:2:1, totaling 30 g. The three modified α-SiC powders were mixed evenly and added in batches to the mixed dispersion prepared in Example 2. The batch additions were 10 g, 5 g, 4 g, 3 g, 2 g, 2 g, and 2 g respectively, with the remaining 2 g added in 10 separate additions. A mechanical stirrer was continuously operated at 300 r / min. During the batch addition of the salt-modified α-SiC powder, the viscosity of the slurry was monitored in real time to obtain the maximum solid content when the viscosity was less than 1.0 Pa·s (meaning the powder was not completely used up during the addition process). The slurry was then continuously stirred for 24 h.
[0057] In this embodiment, theoretically, 30g of aluminum salt-modified α-SiC powder is dissolved in 5mL of the mixed dispersion from Example 2 to obtain a ceramic slurry with a solid content of 65 vol.%. However, in actual addition, the state of the slurry changes or even fails to form a slurry as the mass of silicon carbide powder increases. Therefore, to maintain the stability of the slurry, solvents such as deionized water, ethylene glycol, or isopropanol are added to the slurry during preparation to maintain its properties. However, this reduces the solid content of the slurry due to the increase in liquid volume. Therefore, in this embodiment, 30g of silicon carbide powder is completely added, and the amount of solvent is supplemented during the slurry preparation process. Ultimately, this embodiment can obtain a slurry with a solid content of 55-57 vol.%, a viscosity of 0.5672-0.5996 Pa·s, and a silicon carbide slurry stability h / h0 = 5.160-5.421%.
[0058] The slurry with a solid content of 55 vol.% was supplemented with 1.8 mL of ethylene glycol and 0.7 mL of isopropanol during the pulping process, and its viscosity was 0.5672 Pa·s, with a stability of 5.160%. The slurry with a solid content of 57 vol.% was supplemented with 1 mL of ethylene glycol and 1 mL of isopropanol during the pulping process, and its corresponding viscosity was 0.5596 Pa·s, with a stability of 5.421%.
[0059] Comparative Example 1
[0060] In this embodiment, the dispersants are tetramethylammonium hydroxide and ethylene glycol.
[0061] Add 2.4 g of 25% tetramethylammonium hydroxide aqueous solution (1.8 mL of water), 1.5 mL of ethylene glycol, and 2.7 mL of deionized water to a beaker, and stir evenly with a mechanical stirrer at a speed of 400 r / min for 15 min to obtain a mixed dispersion.
[0062] The slurry was prepared according to the conditions in Example 3, and a silicon carbide slurry with a solid content of 60 vol% was obtained. The slurry had poor fluidity and a viscosity of 5.34 Pa·s at a shear rate of 60 1 / s, which is greater than 1.0 Pa·s.
[0063] Comparative Example 2
[0064] In this embodiment, the dispersants are tetramethylammonium hydroxide and isopropanol.
[0065] Add 2.4 g of 25% tetramethylammonium hydroxide aqueous solution (1.8 mL of water), 1 mL of isopropanol, and 3.2 mL of deionized water to a beaker, and stir evenly with a mechanical stirrer at a speed of 400 r / min for 15 min to obtain a mixed dispersion.
[0066] The slurry was prepared according to the conditions in Example 3, and a silicon carbide slurry with a solid content of 60 vol% was barely obtained. The slurry had poor fluidity and a high viscosity that was difficult to measure.
[0067] Comparative Example 3
[0068] In this embodiment, the dispersants are ethylene glycol and isopropanol.
[0069] Add 1.5 mL of ethylene glycol, 1 mL of isopropanol and 2.5 mL of deionized water to a beaker, stir evenly with a mechanical stirrer at a speed of 400 r / min for 15 min to obtain a mixed dispersion.
[0070] When a slurry is prepared according to the conditions in Example 3, it cannot be formed when the solid content is 43 vol.%. This is because the absence of tetramethylammonium hydroxide increases the zeta potential of the silicon carbide powder surface, weakens the electrostatic repulsion between the silicon carbide powders, and makes them more prone to agglomeration, making it difficult to form a slurry.
[0071] Comparative Example 4
[0072] Replace with a different solvent.
[0073] The dispersant cannot be replaced with ethanol, butanone, n-butanol, toluene, or ethyl acetate.
[0074] Tetramethylammonium hydroxide, acting as a dispersant, hydrolyzes in the slurry to produce hydroxyl groups, providing a strongly alkaline environment. Another hydrolysis product adsorbs onto the surface of silicon carbide particles, increasing the thickness of the double electron layer, which reduces the Zeta potential of the silicon carbide particles and improves the dispersibility of the slurry. Meanwhile, isopropanol and ethylene glycol can be adsorbed onto the surface of silicon carbide particles through hydrogen bonds or van der Waals forces to form an adsorption layer that acts as a steric hindrance, while other organic compounds with different functional groups cannot be effectively adsorbed onto the surface of silicon carbide particles to form a steric hindrance.
[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A silicon carbide ceramic slurry with high solids content and low viscosity, characterized in that, The components of the silicon carbide ceramic slurry include: aluminum salt modified α-SiC powder and dispersant, wherein the dispersant includes tetramethylammonium hydroxide, ethylene glycol and isopropanol; The mass ratio of the aluminum salt-modified α-SiC powder to tetramethylammonium hydroxide, ethylene glycol, and isopropanol is 100:2:5.5~6.1:2.
6.
2. The silicon carbide ceramic slurry as described in claim 1, characterized in that, The mass ratio of the aluminum salt-modified α-SiC powder to tetramethylammonium hydroxide, ethylene glycol, and isopropanol is 100:2:5.5:2.
6.
3. The silicon carbide ceramic slurry as described in claim 1, characterized in that, The preparation method of aluminum salt modified α-SiC powder includes: placing α-SiC powder and aluminum salt in deionized water, heating and stirring, and collecting the solid, which is the aluminum salt modified α-SiC powder.
4. The silicon carbide ceramic slurry as described in claim 3, characterized in that, The α-SiC powder includes α-SiC powders with particle sizes of 0.5 μm, 2.5 μm, and 10 μm. Alternatively, the aluminum salt may include Al(NO3)3.
5. The silicon carbide ceramic slurry as described in claim 4, characterized in that, The mass ratio of α-SiC powder with a particle size of 0.5 μm, α-SiC powder with a particle size of 2.5 μm, and α-SiC powder with a particle size of 10 μm is 2 ~ 7 : 2 ~ 8 : 1 ~ 7.
6. The silicon carbide ceramic slurry as described in claim 5, characterized in that, The mass ratios of α-SiC powder with a particle size of 0.5 μm, α-SiC powder with a particle size of 2.5 μm, and α-SiC powder with a particle size of 10 μm are 5:8:7, 3:4:3, 7:8:5, or 2:2:
1.
7. The silicon carbide ceramic slurry as described in claim 4, characterized in that, The mass ratio of α-SiC powder to Al(NO3)3 is 1:0.002~0.
008.
8. The silicon carbide ceramic slurry as described in claim 3, characterized in that, The heating and stirring temperature is 50 ~ 80 ℃, and the heating and stirring time is 3 ~ 6 h.
9. The silicon carbide ceramic slurry as described in claim 3, characterized in that, The method for collecting solids includes centrifugation to remove the supernatant and then obtaining aluminum salt-modified α-SiC powder.
10. The silicon carbide ceramic slurry as described in claim 9, characterized in that, The centrifugation rate is 3500 ~ 4500 r / min, and the centrifugation time is 5 ~ 10 min.
11. The silicon carbide ceramic slurry as described in claim 3, characterized in that, After collecting and drying the solid, pass it through an 80-100 mesh sieve to obtain aluminum salt modified α-SiC powder.
12. A method for preparing silicon carbide ceramic slurry according to any one of claims 1 to 11, characterized in that, include: A mixed dispersion was obtained by mixing tetramethylammonium hydroxide, ethylene glycol, isopropanol and deionized water. Aluminum salt-modified α-SiC powder was added to the mixed dispersion in batches and stirred to obtain silicon carbide ceramic slurry.
13. The preparation method according to claim 12, characterized in that, Tetramethylammonium hydroxide, ethylene glycol, isopropanol and deionized water were stirred and mixed to obtain a mixed dispersion, wherein the stirring speed was 200 ~ 400 r / min and the stirring time was 10 ~ 15 min.
14. The preparation method according to claim 12, characterized in that, When aluminum salt-modified α-SiC powder is added to the mixed dispersion in batches and stirred to obtain silicon carbide ceramic slurry, the stirring speed is 100 ~ 400 r / min and the stirring time is 16 ~ 24 h.