Preparation method and application of ceramic isolation film on the surface of carbon-carbon thermal field structure

Abstract

The present application relates to the technical field of carbon-carbon composite materials, and in particular to a preparation method and application of a ceramic isolation membrane on the surface of a carbon-carbon thermal field structure. The preparation method of the ceramic isolation membrane on the surface of the carbon-carbon thermal field structure comprises the following preparation steps: S1, preparing a ceramic impregnation liquid, and impregnating a carbon cloth with the ceramic impregnation liquid to obtain an impregnated carbon cloth; S2, preparing a ceramic adhesive; S3, preparing a ceramic slurry; S4, polishing the inner surface of the carbon-carbon thermal field structure, coating it with a ceramic adhesive, pasting the impregnated carbon cloth, and brushing it with ceramic slurry, and then performing isostatic infiltration; S5, ceramicizing and sintering the carbon-carbon thermal field structure after isostatic infiltration to form a ceramic isolation membrane on the inner surface of the carbon-carbon thermal field structure; the method has the advantages of making the ceramic isolation membrane on the surface of the carbon-carbon thermal field structure continuous and corrosion-resistant.

Description

Technical Field

[0001] The present application relates to the technical field of carbon-carbon composite materials, and in particular to a method for preparing and applying a ceramic isolation film on the surface of a carbon-carbon thermal field structure. Background Art

[0002] Carbon-carbon thermal field structural components generally include carbon-carbon guide tubes, carbon-carbon crucible ribs, and insulation tubes. For example, the carbon-carbon crucible ribs have the advantages of low density, high specific strength, high thermal conductivity, low expansion coefficient, good thermal shock resistance, and high dimensional stability, making them the core thermal field structural components of single crystal silicon vertical pulling furnaces. During the crystal pulling process, the carbon-carbon crucible ribs are adjacent to the quartz crucible that holds the silicon material. The quartz crucible and the carbon-carbon crucible ribs undergo decarburization and silicification at high temperatures, generating loose, discontinuous, and brittle silicon carbide on the inner surface of the crucible ribs. The difference in thermal expansion coefficients between the crucible ribs and silicon carbide causes thermal stress on the inner surface of the crucible ribs during repeated crystal pulling processes, and external mechanical stress is generated during the process of extracting the crystal rod, causing the inner surface of the crucible ribs to peel or even fall off over a large area, severely reducing the service life of the crucible ribs and increasing the cost of crystal pulling.

[0003] At present, due to the similar thermal expansion coefficients of silicon carbide and carbon-carbon crucible ribs, it is often used to improve the corrosion resistance of the crucible ribs. Patent CN103553711A proposes to prepare a composite coating of silicon carbide coating / silicon coating / silicon nitride coating on the surface of a carbon / carbon composite insulation tube, so as to effectively inhibit the corrosion of the surface of the carbon / carbon insulation tube by silicon vapor generated after the silicon material is melted. However, the cost of preparing silicon carbide by chemical vapor infiltration is high, the cycle is long, and the efficiency is low. CN11848201A proposes to use a plasma spraying process to form a SiC / Si coating on the surface of the carbon-carbon crucible ribs to improve the anti-siliconization corrosion ability of the carbon-carbon crucible ribs, thereby increasing the service life of the crucible ribs. However, due to the appearance characteristics of the crucible ribs, it is difficult to achieve a uniform coating on the crucible ribs surface by using a plasma spraying process, and the resulting coating is thin and the thermal expansion coefficients do not match, which has a very limited ability to inhibit silicon vapor corrosion. Furthermore, the SiC impregnation cracking method has high raw material costs, long cycles, and discontinuous surface coatings. Siliconization is also costly, produces large amounts of residual silicon, and is also susceptible to the risk of cracking due to a mismatch in the thermal expansion coefficients of silicon and carbon. Furthermore, the mechanical forces generated by knocking during the actual crystal ingot extraction process increase the risk of silicon carbide layer shedding. Therefore, developing a simple, fast, and low-cost method to improve the corrosion resistance of the crucible rim is crucial. Summary of the Invention

[0004] In order to make the ceramic isolation film on the surface of the carbon-carbon thermal field structure continuous and corrosion-resistant and extend the service life of the carbon-carbon thermal field structure, the present application provides a preparation method and application of the ceramic isolation film on the surface of the carbon-carbon thermal field structure.

[0005] In a first aspect, the present application provides a method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, using the following technical solution:

[0006] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, comprising the following steps:

[0007] S1. preparing a ceramic impregnation solution, and impregnating a carbon cloth with the ceramic impregnation solution to obtain an impregnated carbon cloth;

[0008] S2. preparing a ceramic adhesive;

[0009] S3, preparing ceramic slurry;

[0010] S4, grinding the inner surface of the carbon-carbon thermal field structure, coating it with ceramic adhesive, pasting it with impregnated carbon cloth, and brushing it with ceramic slurry, and then performing isostatic infiltration;

[0011] S5. Ceramic-sintering the carbon-carbon thermal field structure component after isostatic pressing and infiltration to form a ceramic isolation film on the inner surface of the carbon-carbon thermal field structure component.

[0012] By adopting the above technical solution, by impregnating the carbon cloth in the ceramic impregnation liquid, the carbon cloth can enhance the toughness and strength of the ceramic impregnation liquid through its own high strength and excellent tensile strength, thereby improving the continuity of the ceramic isolation membrane; by using ceramic adhesive, the carbon cloth reinforced ceramic isolation membrane and the carbon-carbon thermal field structure can be tightly bonded, thereby further alleviating the mismatch force caused by the inconsistency of the thermal expansion coefficient between the ceramic isolation membrane and the carbon-carbon crucible side. After high-temperature treatment, the ceramic isolation membrane is well bonded to the inner surface of the crucible side without cracks or powder. The inner surface of the carbon-carbon thermal field structure is polished so that its inner surface has a completely frosted texture, which can fully contact with the ceramic adhesive and has good bonding with the ceramic adhesive. Better yet, after bonding with the impregnated carbon cloth, apply ceramic slurry, and after isostatic pressing and infiltration, make the impregnated carbon cloth close to the inner surface of the carbon-carbon thermal field structure, and then perform porcelain sintering under vacuum conditions to form a continuous and dense ceramic isolation membrane on the inner surface of the carbon-carbon thermal field structure; compared with the existing technology, the method of preparing a ceramic isolation membrane on the inner surface of the carbon-carbon thermal field structure in the present application is not only simple to operate, but also shortens the preparation cycle and reduces the preparation cost. The prepared ceramic isolation membrane is continuous, resistant to high temperatures and has excellent corrosion resistance. When applied to, for example, the carbon-carbon crucible side, it can better prevent the quartz crucible from directly contacting the carbon-carbon crucible side, eliminate silicification and decarbonization, and does not change the use characteristics of the carbon-carbon crucible side in crystal pulling, thereby making up for the shortcomings of the existing technology.

[0013] Preferably, the ceramic impregnation solution comprises the following raw materials in percentage by mass: 1-5% silicon carbide, 5-10% silicon powder, and the balance being aluminum sol.

[0014] By adopting the above technical solution, the ceramic impregnation liquid prepared in this application has a simple formula, does not require other auxiliary materials, has good adhesion to the carbon cloth, and has good film-forming properties after high-temperature firing.

[0015] Preferably, the carbon cloth is any one of 1K-12K.

[0016] By adopting the above technical solution, 1K-12K carbon cloth has the advantages of high strength and good tensile properties, can withstand large external forces without being easily deformed, and has excellent corrosion resistance. The present application uses 1K-12K carbon cloth to form a continuous ceramic isolation film on the inner surface of the carbon-carbon thermal field structure.

[0017] Preferably, the ceramic adhesive comprises the following raw materials in percentage by weight: 0.15-0.4% curing agent, 5-15% carbon felt powder, 15-25% asphalt powder, 3-10% graphite powder, 1-5% silicon carbide, 5-10% silicon powder, and the remainder is furan resin.

[0018] By adopting the above technical solution and selecting the raw materials and dosage of the ceramic adhesive, the carbon-carbon thermal field structure can be tightly bonded to the impregnated carbon cloth.

[0019] Preferably, the ceramic slurry comprises the following raw materials in percentage by mass: 50-70% silicon powder, 5-20% ethanol, and the remainder being phenolic resin.

[0020] By adopting the above technical solution, ethanol and phenolic resin can disperse the silicon powder evenly.

[0021] Preferably, in S4, the grinding depth of the inner surface of the carbon-carbon thermal field structure is 0.5-1.1 mm.

[0022] By adopting the above technical solution, the grinding thickness of the inner surface of the carbon-carbon thermal field structure also has a certain impact on the ceramic isolation membrane. A low grinding depth is not conducive to the bonding between the inner surface of the carbon-carbon thermal field structure and the ceramic adhesive, resulting in the formation of pores between the ceramic isolation membrane and the inner surface of the carbon-carbon thermal field structure. This leads to poor continuity of the ceramic isolation membrane and is prone to cracking.

[0023] Preferably, the coating thickness of the ceramic adhesive is 0.2-0.8 mm.

[0024] By adopting the above technical solution, the thickness of the ceramic adhesive can be 0.2-0.8 mm, which can ensure good adhesion of the impregnated carbon cloth.

[0025] As an example, the parameter conditions of the isostatic infiltration are as follows:

[0026] Evacuate the chamber and raise the temperature to 170-200°C for 5-8 hours. After heating, keep the chamber warm for 1-2 hours. Pressurize the chamber when the temperature reaches 50-70°C at a pressure of 1.5-2.5 MPa. Maintain the pressure during the heating and insulation process.

[0027] As an example, the parameters of the porcelain sintering are as follows:

[0028] Evacuate the chamber and heat to 1550-1650℃ for 40-50 hours. After heating, keep warm for 2-4 hours.

[0029] As a preferred embodiment, if the temperature is raised too quickly, it will be detrimental to the close contact between the impregnated carbon cloth and the inner surface of the carbon-carbon thermal field structure, thereby affecting the continuity of the ceramic isolation membrane.

[0030] In a second aspect, the present application provides an application of a method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, using the following technical solution:

[0031] The invention discloses an application of a method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure is applied to a carbon-carbon guide tube, a carbon-carbon crucible side or an insulation tube.

[0032] By adopting the above technical solution, the preparation method of the ceramic isolation film on the surface of the carbon-carbon thermal field structure of the present application can be applied to various carbon-carbon thermal field structures such as carbon-carbon guide tubes, carbon-carbon crucible sides and insulation tubes, and has strong adaptability.

[0033] In summary, this application includes at least one of the following beneficial technical effects:

[0034] 1. By impregnating the carbon cloth in the ceramic impregnation liquid, the carbon cloth can enhance the toughness and strength of the ceramic impregnation liquid through its own high strength and excellent tensile strength, thereby improving the continuity of the ceramic isolation membrane; the use of ceramic adhesive can achieve close bonding between the carbon cloth reinforced ceramic isolation membrane and the carbon-carbon thermal field structure, thereby further alleviating the mismatch force caused by the inconsistency of the thermal expansion coefficient between the ceramic isolation membrane and the carbon-carbon thermal field structure. After high-temperature treatment, the ceramic isolation membrane is well bonded to the inner surface of the crucible without cracks or powder.

[0035] 2. Compared with the prior art, the method of preparing a ceramic isolation membrane on the inner surface of a carbon-carbon thermal field structure in the present application is not only easy to operate, but also shortens the preparation cycle and reduces the preparation cost. The prepared ceramic isolation membrane is continuous, resistant to high temperatures and has excellent corrosion resistance. When applied to the carbon-carbon crucible side, it can better prevent the quartz crucible from directly contacting the carbon-carbon crucible side, eliminate silicification and decarbonization, and does not change the use characteristics of the carbon-carbon crucible side in crystal pulling, thereby greatly extending the service life of the carbon-carbon thermal field structure.

[0036] 3. The carbon-carbon crucible side prepared by the method of preparing a ceramic isolation membrane on the inner surface of a carbon-carbon thermal field structure of the present application was subjected to a silicification erosion test at 1600°C for 60 hours. The ceramic isolation membrane on its inner surface showed no corrosion, and the ceramic isolation membrane was well bonded to the substrate, without cracks or powder falling off. The weight loss rate was between 0.010-0.016%. This indicates that the method of preparing a ceramic isolation membrane on the surface of a carbon-carbon crucible side of the present application can form a continuous, corrosion-resistant ceramic isolation membrane on the inner surface of the carbon-carbon crucible side, which can greatly extend the service life of the carbon-carbon crucible side. DETAILED DESCRIPTION

[0037] The following is a further detailed description of this application in conjunction with the specific content.

[0038] raw material

[0039] The raw materials used in this application are all purchased from the market, among which the particle size of silicon carbide powder is 500 mesh and the silicon content is ≥99%; the particle size of silicon powder is 600 mesh and the silicon dioxide content is ≥97%; the aluminum sol is industrial grade aluminum sol; the model of furan resin is 102 and the content is ≥98%; the model of curing agent is MDI-50; the particle size of carbon felt powder is 100 mesh; the particle size of asphalt powder is 100 mesh; and the particle size of graphite powder is 2000 mesh.

[0040] Example

[0041] Example 1

[0042] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, taking a carbon-carbon crucible rib as an example, comprises the following preparation steps: S1, preparing a ceramic impregnation solution: adding silicon carbide powder and silicon powder to aluminum sol at once, with the mass percentages of silicon carbide powder and silicon powder being 3% and 7%, respectively, and the balance being aluminum sol; stirring evenly, and allowing to stand for 24 hours for use;

[0043] S2. Stir the ceramic impregnation liquid evenly, add 3K carbon cloth, and soak for 10 minutes. The impregnated carbon cloth is rolled on a small impregnation machine to obtain an impregnated 3K carbon cloth with a thickness of 0.25 mm. Let it dry naturally for 2 hours for use.

[0044] S3. Prepare ceramic adhesive: Add 60% furan resin, 0.2% curing agent, 7% carbon felt powder, 20% asphalt powder, 5% graphite powder, 1.8% silicon carbide and 6% silicon powder to a stainless steel container in order by weight. Stir for 5 minutes after adding each material. After all materials are added, continue stirring for 40 minutes until the materials are uniform. Seal the container and let it stand at 22-30°C for 24 hours for use.

[0045] S4. Prepare ceramic slurry: according to the percentage by mass: mix 40% phenolic resin, 52% silicon powder, and 8% ethanol, stir evenly, and let it stand for 24 hours;

[0046] S5. Grind the inner surface of the carbon-carbon crucible to a depth of 1 mm, clean, and dry;

[0047] S6. Coat the inner surface of the carbon-carbon crucible with a ceramic adhesive having a thickness of 0.7 mm, and evenly and evenly adhere the impregnated 3K carbon cloth to the polished inner surface of the carbon-carbon crucible through the ceramic adhesive. Then, evenly apply a layer of ceramic slurry on the surface of the impregnated 3K carbon cloth, with a coating thickness of 0.15 mm. Then, perform isostatic infiltration. After evacuation, uniformly heat to 180° C. for 6 hours, and keep at 180° C. for 2 hours. When the temperature reaches 60° C., pressurize to 1.8 MPa, and maintain the pressure at 1.8 MPa during the heating and holding process.

[0048] After the heat preservation in S7 and S6 is completed, ceramic sintering is carried out, vacuum is drawn, and then the temperature is evenly raised to 1600°C for 40 hours. The temperature is kept at 1600°C for 2 hours and naturally cooled. The continuous ceramic isolation film on the inner surface of the carbon-carbon crucible is completed.

[0049] Example 2

[0050] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, taking a carbon-carbon crucible as an example, includes the following preparation steps:

[0051] S1. Prepare ceramic impregnation solution: Add silicon carbide powder and silicon powder to aluminum sol at once, with the mass percentage of silicon carbide powder and silicon powder being 5% and 8% respectively, and the balance being aluminum sol. Stir well and let stand for 24 hours;

[0052] S2. Stir the ceramic impregnation liquid evenly, add 1K carbon cloth, and soak for 10 minutes. The impregnated carbon cloth is rolled on a small impregnation machine to obtain an impregnated 1K carbon cloth with a thickness of 0.2 mm. Let it dry naturally for 1.5 hours for use.

[0053] S3. Prepare ceramic adhesive: Add 52% furan resin, 0.2% curing agent, 10% carbon felt powder, 20% asphalt powder, 10% graphite powder, 2% silicon carbide, and 5.8% silicon powder to a stainless steel container in order by mass percentage. Stir for 5 minutes after each addition. After all the materials are added, continue stirring for 40 minutes until the materials are uniform. Seal the container and let it stand at 22-30°C for 24 hours for use.

[0054] S4. Prepare ceramic slurry: according to the percentage by mass: mix 45% phenolic resin, 50% silicon powder, and 5% ethanol, stir evenly, and let it stand for 24 hours;

[0055] S5. Grind the inner surface of the carbon-carbon crucible to a depth of 1 mm, clean, and dry;

[0056] S6. Coat the inner surface of the carbon-carbon crucible with a ceramic adhesive having a thickness of 0.55 mm, and evenly and evenly adhere the impregnated 1K carbon cloth to the polished inner surface of the carbon-carbon crucible through the ceramic adhesive. Then, evenly apply a layer of ceramic slurry on the surface of the impregnated 1K carbon cloth, with a coating thickness of 0.25 mm. Then, perform isostatic infiltration. After evacuation, uniformly heat to 180° C. for 5 hours, and keep at 180° C. for 2 hours. When the temperature reaches 60° C., pressurize to 1.8 MPa, and maintain the pressure at 1.8 MPa during the heating and holding process.

[0057] After the heat preservation in S7 and S6 is completed, ceramic sintering is carried out, vacuum is drawn, and then the temperature is evenly raised to 1600°C for 40 hours. The temperature is kept at 1600°C for 2 hours and naturally cooled. The continuous ceramic isolation film on the inner surface of the carbon-carbon crucible is completed.

[0058] Example 3

[0059] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure component is different from that of Example 2 in that, in S2, the carbon cloth is 12K carbon cloth, and the remaining steps are the same as those of Example 2.

[0060] Example 4

[0061] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that, in S5, the inner surface of the carbon-carbon crucible side is polished to a thickness of 0.5 mm, and the remaining steps are the same as Example 2.

[0062] Example 5

[0063] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that, in S6, the thickness of the ceramic adhesive coated on the inner surface of the carbon-carbon crucible side is 0.2 mm, and the remaining steps are the same as Example 2.

[0064] Example 6

[0065] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that, in S6, the thickness of the ceramic adhesive coated on the inner surface of the carbon-carbon crucible side is 0.8 mm, and the remaining steps are the same as Example 2.

[0066] Comparative Example

[0067] Comparative Example 1

[0068] A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that the inner surface of the carbon-carbon crucible side is polished in S5 with a polishing depth of 0.2 mm, and the remaining steps are the same as Example 2.

[0069] Comparative Example 2

[0070] A method for preparing a ceramic isolation membrane on the surface of a carbon-carbon thermal field structure component is different from that of Example 2 in that, in S6, no pressurization is performed when the temperature is raised to 60° C., and the remaining steps are the same as those of Example 2.

[0071] Comparative Example 3

[0072] A method for preparing a ceramic isolation membrane on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that, after the insulation in S7 is completed, ceramic sintering is performed, vacuum is evacuated, and then the temperature is uniformly raised to 1600°C for 25 hours. The temperature is kept at 1600°C for 2 hours and naturally cooled. The remaining steps are the same as Example 2.

[0073] Comparative Example 4

[0074] A method for preparing a ceramic isolation membrane on the surface of a carbon-carbon thermal field structure component is different from Example 2 in that the impregnated 1K carbon cloth is replaced with a ceramic impregnation liquid of equal thickness in S6, and the remaining steps are the same as Example 2.

[0075] Performance testing

[0076] Detection method / test method

[0077] According to the preparation methods of Examples 1-6 and Comparative Examples 1-4, carbon-carbon crucible sides with ceramic isolation membranes on the inner surfaces were prepared respectively, and then subjected to a silicification corrosion test at 1600°C for 60 hours. The ceramic isolation membranes were then observed for corrosion, whether the ceramic isolation membranes were well bonded to the substrate, whether there were cracks, and whether there was powder falling. The weight loss rate was calculated, and the results are shown in Table 1.

[0078] Table 1 Test results of Examples 1-6 and Comparative Examples 1-4

[0079]

[0080] It can be seen from Examples 1-6 and Comparative Examples 1-3, as well as the test data in Table 1, that after the carbon-carbon crucible side prepared in the present application was subjected to a silicification erosion test at 1600°C for 60 hours, the ceramic isolation membrane on its inner surface showed no corrosion, the ceramic isolation membrane was well bonded to the substrate, no cracks appeared, no powder fell off, and the weight loss rate was between 0.010-0.016%. This indicates that the preparation method of the ceramic isolation membrane on the surface of the carbon-carbon crucible side of the present application can form a continuous, corrosion-resistant ceramic isolation membrane on the inner surface of the carbon-carbon crucible side, which can greatly extend the service life of the carbon-carbon crucible side.

[0081] The test data of Examples 1-2 and Comparative Example 4 show that by preparing a ceramic impregnation liquid and using it to prepare an impregnated carbon cloth, ceramic adhesives and ceramic slurries are also prepared, and the inner surface of the carbon-carbon crucible rib is polished to a completely frosted texture, allowing for full contact with the ceramic adhesive and better adhesion to the ceramic adhesive. The impregnated carbon cloth is then bonded to the impregnated carbon cloth and then coated with ceramic slurry. After isostatic pressure penetration, the impregnated carbon cloth is tightly attached to the inner surface of the carbon-carbon crucible rib, and then porcelain sintering is performed under vacuum conditions to form a continuous ceramic isolation membrane on the inner surface of the carbon-carbon crucible rib. Under vacuum and high temperature conditions, the furan resin and other substances in the ceramic adhesive decompose and volatilize, allowing the impregnated carbon cloth and other substances to adhere more tightly to the inner surface of the carbon-carbon crucible rib. The carbon cloth can enhance the toughness and strength of the ceramic impregnation liquid through its own high strength and excellent tensile strength, thereby improving the continuity of the ceramic isolation membrane.

[0082] The test data from Examples 1-3 demonstrate that 1K-12K carbon cloth has the advantages of high strength and good tensile properties, can withstand large external forces without deformation, and has excellent corrosion resistance. In this application, 1K-12K carbon cloth all resulted in a continuous ceramic barrier film formed on the inner surface of the carbon-carbon crucible rib. In conjunction with Example 4 and Comparative Example 1, the grinding thickness of the inner surface of the carbon-carbon crucible rib also has a certain impact on the ceramic barrier film. A low grinding depth is not conducive to bonding between the inner surface of the carbon-carbon crucible rib and the ceramic adhesive, resulting in pores between the ceramic barrier film and the inner surface of the carbon-carbon crucible rib, and thus poor continuity of the ceramic barrier film.

[0083] It can be seen from the test data of Example 2 and Examples 5-6 that the thickness of the ceramic adhesive can achieve good adhesion of the impregnated carbon cloth when it is 0.2-0.8 mm.

[0084] The test data of Example 2 and Comparative Examples 2-3 show that the lack of pressurization in S6 or the rapid temperature increase in S7 are not conducive to the close contact between the impregnated carbon cloth and the inner surface of the carbon-carbon crucible, thereby affecting the continuity of the ceramic separator.

[0085] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure, characterized by: It comprises the following preparation steps: S1. preparing a ceramic impregnation solution, and impregnating a carbon cloth with the ceramic impregnation solution to obtain an impregnated carbon cloth; S2. preparing a ceramic adhesive; S3, preparing ceramic slurry; S4, grinding the inner surface of the carbon-carbon thermal field structure, coating it with ceramic adhesive, pasting it with impregnated carbon cloth, and brushing it with ceramic slurry, and then performing isostatic infiltration; S5, ceramic sintering the carbon-carbon thermal field structure after isostatic infiltration to form a ceramic isolation film on the inner surface of the carbon-carbon thermal field structure; In said S4, the grinding depth of the inner surface of the carbon-carbon thermal field structure is 0.5-1.1 mm; The parameter conditions of the isostatic infiltration are as follows: Evacuate the chamber and raise the temperature to 170-200°C for 5-8 hours. After heating, keep the chamber warm for 1-2 hours. Pressurize the chamber to 1.5-2.5 MPa when the temperature reaches 50-70°C. Maintain the pressure during the heating and insulation process. The parameter conditions of the porcelain sintering are as follows: Evacuate the chamber and heat to 1550-1650℃ for 40-50 hours. After heating, keep warm for 2-4 hours.

2. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to claim 1, characterized in that: The ceramic impregnation solution includes the following raw materials in percentage by weight: 1-5% silicon carbide, 5-10% silicon powder, and the balance being aluminum sol.

3. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to claim 1, characterized in that: The carbon cloth is any one of 1K-12K.

4. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to claim 1, characterized in that: The ceramic adhesive comprises the following raw materials in percentage by weight: 0.15-0.4% curing agent, 5-15% carbon felt powder, 15-25% asphalt powder, 3-10% graphite powder, 1-5% silicon carbide, 5-10% silicon powder, and the balance is furan resin.

5. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to claim 1, characterized in that: The ceramic slurry comprises the following raw materials in percentage by weight: 50-70% silicon powder, 5-20% ethanol, and the balance being phenolic resin.

6. The method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to claim 1, characterized in that: The coating thickness of the ceramic adhesive is 0.2-0.8 mm.

7. An application of the method for preparing a ceramic isolation film on the surface of a carbon-carbon thermal field structure according to any one of claims 1 to 6, characterized in that: The method for preparing the ceramic isolation film on the surface of the carbon-carbon thermal field structural component is used for preparing a carbon-carbon guide tube, a carbon-carbon crucible rim and a heat preservation tube.

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