Carbon material surface ta c coating and method for preparing the same

Abstract

The present application relates to the technical field of semiconductor crystal growth, and particularly relates to a TaC coating on the surface of carbon material, which comprises a transition layer and a surface layer, wherein the transition layer slurry is obtained by mixing graphite powder, phenolic resin, epoxy resin, anhydrous ethanol, distilled water and silane coupling agent, and the transition layer is formed by coating the transition layer slurry on the surface of the carbon material; the surface layer slurry is obtained by mixing TaC powder, boron oxide powder, phenolic resin, anhydrous ethanol, distilled water and silane coupling agent, and the surface layer is formed by coating the surface layer slurry on the side of the transition layer away from the carbon material. The TaC coating prepared by the present application has better corrosion resistance and thermal shock resistance, and has a longer service life.

Description

Technical Field

[0001] This invention relates to the field of semiconductor crystal growth technology, specifically to a TaC coating on the surface of carbon materials and its preparation method. Background Technology

[0002] Semiconductor crystal growth typically takes place in high-temperature, high-purity environments, using primarily carbon-based structural components such as carbon-carbon composites and graphite. Due to the inherent porosity of commonly used carbon-based structural components, their corrosion resistance is relatively low. Prolonged exposure to the high temperatures of semiconductor crystal growth makes them susceptible to silicon vapor erosion, leading to surface damage, contamination of the silicon crystal, and a significant decrease in carbon material strength, severely impacting their lifespan. While some progress has been made in SiC coating, it is prone to reaction with the ambient atmosphere during SiC epitaxy, affecting product quality. TaC, with its superior physical and chemical properties, exhibits far greater high-temperature chemical stability and corrosion resistance than SiC, meeting temperatures up to 2600℃. Using TaC coating equipment can solve the problem of edge defects in semiconductor crystals, improving their quality.

[0003] Currently, the main methods for preparing TaC coatings include molten salt method, sol-gel method, slurry sintering method, plasma spraying method, chemical vapor deposition (CVD), chemical vapor infiltration (CVI), and physical vapor deposition (PVD). This invention focuses on the "slurry sintering method," employing a special slurry formulation and coating technique to provide a high-yield, low-cost TaC coating process, thereby improving the service life and application range of coated carbon components in semiconductor crystal growth environments. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a TaC coating for densification and protection of carbon material surfaces, and its preparation method. This method primarily aims to improve the service life of carbon materials in the semiconductor field and expand their application range. The preparation method provided by this invention mainly addresses the coating cracking problem caused by the difference in thermal expansion between the TaC coating and the carbon substrate, thereby improving the adhesion between the TaC coating and the carbon substrate.

[0005] Technical solution

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a TaC coating on the surface of a carbon material, comprising a transition layer and a surface layer.

[0008] The transition layer comprises graphite powder, phenolic resin, epoxy resin, anhydrous ethanol, distilled water, and silane coupling agent. The transition layer slurry is obtained by mixing graphite powder, phenolic resin, epoxy resin, anhydrous ethanol, distilled water, and silane coupling agent, and then the transition layer slurry is coated onto the surface of the carbon material to form the transition layer.

[0009] The surface layer comprises TaC powder, boron oxide powder, phenolic resin, anhydrous ethanol, distilled water, and silane coupling agent. A surface layer slurry is obtained by mixing TaC powder, boron oxide powder, phenolic resin, anhydrous ethanol, distilled water, and silane coupling agent. The surface layer slurry is then coated onto the side of the transition layer away from the carbon material to form the surface layer.

[0010] Furthermore, by weight, the transition layer comprises:

[0011] 2-5 parts graphite powder, 5-10 parts phenolic resin, 1-2 parts epoxy resin, 5-8 parts anhydrous ethanol, 21-32 parts distilled water and 0.002-0.005 parts silane coupling agent.

[0012] Specifically, the preparation steps of the transition layer slurry are as follows:

[0013] 1) When preparing the transition layer slurry, first dissolve the phenolic resin PF7203 in the anhydrous ethanol and stir thoroughly to obtain a uniformly dissolved concentrated solution of phenolic resin.

[0014] 2) Slowly add the distilled water to the concentrated phenolic resin solution and continue stirring until fully dissolved and homogeneous to obtain a dilute phenolic resin solution;

[0015] 3) Add the epoxy resin AG-80 to the dilute phenolic resin solution, stir and dissolve evenly to obtain a resin mixture solution;

[0016] 4) Add the γ-aminopropyltriethoxysilane to the resin mixture and stir until homogeneous;

[0017] 5) Finally, add the 800-mesh graphite powder to the above solution and stir evenly to obtain the transition layer slurry.

[0018] Furthermore, by weight, the surface layer comprises:

[0019] 1-5 parts TaC powder, 0.001-0.003 parts boron oxide powder, 14-18 parts phenolic resin, 10-15 parts anhydrous ethanol, 33-45 parts distilled water, and 0.001-0.005 parts silane coupling agent.

[0020] Specifically, the surface layer slurry preparation steps are as follows:

[0021] 1) When preparing the surface layer slurry, first dissolve the phenolic resin PF6908 in the anhydrous ethanol and stir thoroughly to obtain a uniformly dissolved concentrated solution of phenolic resin.

[0022] 2) Slowly add the distilled water to the concentrated phenolic resin solution and continue stirring until fully dissolved and homogeneous to obtain a phenolic resin solution;

[0023] 3) Add the γ-aminopropyltriethoxysilane to the phenolic resin solution and stir until homogeneous;

[0024] 4) Finally, mix the TaC powder and boron oxide powder evenly, add them to the above solution, and stir thoroughly to obtain the surface layer slurry.

[0025] The graphite powder primarily fills the pores on the carbon matrix surface and provides a larger contact area for the surface slurry coating. The phenolic resin acts as an adhesive while also serving as a curing agent for the epoxy resin. The epoxy resin significantly improves the adhesion between the slurry and the carbon matrix. The silane coupling agent mainly increases the affinity between the phenolic resin, epoxy resin, graphite powder, carbon matrix, TaC, and boron oxide. Through physical entanglement and chemical reaction, stronger chemical bonds are formed, improving the tightness between the resin and the carbon materials, TaC, and boron oxide. The TaC powder and boron oxide powder react with other substances at high temperatures, improving the density and toughness of the coating on the carbon matrix surface. The mixture of anhydrous ethanol and distilled water constitutes the main solvent of the slurry components, reducing resin viscosity and improving the dispersion of other components to enhance coating uniformity. The phenolic resin and epoxy resin, while acting as adhesives, provide expansion space for other substances after carbonization, offering a transition zone for differences in thermal expansion of different components.

[0026] Furthermore, the graphite powder is 800-1000 mesh high-purity flake graphite powder with a carbon content ≥99.99%;

[0027] Preferably, the graphite powder is 1000-mesh high-purity flake graphite powder with a carbon content ≥99.99%;

[0028] Optionally, the slurry is made of methyl alcohol-soluble thermosetting phenolic resin liquid with a residual carbon content of 40%-45%.

[0029] Optionally, the slurry uses phenolic resin sourced from Jinan Shengquan Group Co., Ltd., with selected models being PF7203 and PF6908. PF7203 is used for the transition layer slurry, and PF6908 is used for the surface layer slurry.

[0030] Optionally, the epoxy resin used in the slurry is a glycidylamine type epoxy resin liquid, and the selected model is AG-80 or AFG-90.

[0031] Optionally, the epoxy resin used in the slurry is sourced from commercially available materials, and the selected grade is AG80.

[0032] Optionally, the slurry may use γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethylaminosilane, or phenylaminomethyltriethoxysilane as the silane coupling agent.

[0033] Optionally, the slurry may use γ-aminopropyltriethoxysilane or N-phenylaminomethyltriethoxysilane as the silane coupling agent.

[0034] Optionally, the slurry is made of TaC powder with a particle size of 0.5-1.5μm and a purity greater than 99.99%.

[0035] Optionally, the boron oxide powder used in the slurry is ultrafine high-purity boron oxide powder with a particle size of 2500 mesh and a purity greater than 99.9%.

[0036] Furthermore, the thickness of the TaC coating is 30-150 micrometers;

[0037] The thickness of the transition layer is 30-50% of the total coating thickness; the thickness of the surface layer is 50-70% of the total coating thickness.

[0038] A method for preparing a TaC coating on the surface of a carbon material, comprising the following steps:

[0039] (1) Pretreatment of carbon substrate;

[0040] (2) Preparation and application of transition layer slurry: A transition layer slurry is prepared by mixing graphite powder, phenolic resin, epoxy resin, anhydrous ethanol, distilled water and silane coupling agent in a certain weight ratio; after uniformly spraying the transition layer slurry onto the surface of the high-purity carbon substrate, it is placed in an oven and kept at a constant temperature of 180-200℃ for 3-5 hours to achieve curing of the transition layer slurry.

[0041] (3) Preparation and application of surface layer slurry: a surface layer slurry is prepared by mixing TaC powder, boron oxide powder, phenolic resin, anhydrous ethanol, distilled water and silane coupling agent in a certain weight ratio; after uniformly spraying the surface layer slurry onto the surface of the cured transition layer, it is placed in an oven and kept at a constant temperature of 180-200℃ for 3-5 hours to achieve curing of the surface layer slurry.

[0042] (4) Carbon materials with TaC coating are obtained through deposition and sintering processes.

[0043] Furthermore, in step (4), during the deposition process, under the conditions of a deposition temperature of 1050-1200℃ and a vacuum degree of 900-1000Pa, nitrogen gas and propane gas are mixed at a flow rate ratio of 5-20:1, and then injected at a flow rate of 0.2-0.5m. 3 Deposition at a rate of / min for 20-30 hours.

[0044] Furthermore, in step (4), during the sintering process, under the conditions of a temperature of 2000-2500℃ and a vacuum degree of 50-80Pa, after maintaining the temperature for 30-60 minutes, argon gas is introduced at a rate of 0.3-0.4 m³ / min, and the vacuum degree after introducing argon gas is 1500-2000Pa, and sintering continues for 4-5 hours.

[0045] Specifically, in step (4), the sample after the surface layer slurry has been cured is placed in a CVD furnace. Under conditions of 1200℃ and a vacuum of 500-800Pa, nitrogen gas and alkane-propylene gas are mixed at a mass ratio of 10-20:1, and then the mixture is sprayed at a speed of 0.2-0.5m. 3 Deposition was performed at a rate of 0.3-0.4 m / min for 20-30 h. After CVD deposition, the sample was placed in a sintering furnace and held at a temperature of 2000-2500℃ and a vacuum of 50-80 Pa for 30-60 min. 3 Argon gas is introduced at a rate of / min, and the vacuum degree after argon introduction is 1500-2000Pa. Sintering continues for 4-5 hours. After sintering, a dense and uniform TaC-coated carbon part with a coating thickness of 30-120 micrometers is obtained.

[0046] Furthermore, in step (1), the carbon substrate is pretreated by placing the carbon substrate in an ultrasonic bath to clean the surface stains and dust, then drying it, and finally purifying it at 2500°C in a purification furnace to obtain a high-purity carbon substrate.

[0047] Beneficial effects

[0048] The technical solution provided by this invention has the following advantages compared with known public technologies:

[0049] 1. By using ultrasonic cleaning and high-temperature purification of the carbon matrix, the dust, stains and other impurities attached to the surface are removed to obtain a clean and high-purity carbon matrix. This ensures that no other special impurity gases are generated in the special environment of semiconductor crystal growth, completely eliminating the risk of coating blistering. At the same time, it also improves the wettability between the coating and the product surface, and greatly enhances the coating's anti-peel properties.

[0050] 2. By spraying and curing a transition layer slurry, appropriate amounts of graphite powder, phenolic resin, and epoxy resin are introduced to the carbon substrate surface. With subsequent curing, CVD deposition, and sintering processes, the cross-linking strength between the transition layer components and the carbon substrate surface is increased, while the density of the carbon substrate surface is also improved. Furthermore, as the phenolic resin and epoxy resin transform into resin carbon with a coefficient of thermal expansion different from that of the carbon substrate-based graphite powder, together with the graphite powder, they form a transition layer coating with a coefficient of thermal expansion higher than that of the carbon substrate but lower than that of the TaC coating. This provides a buffer zone for the difference in coefficients of thermal expansion between the TaC coating and the carbon substrate, reducing the risk of cracking in the TaC coating.

[0051] 3. Introducing boron oxide into the surface layer slurry effectively improves the sintering degree of the TaC coating, catalyzes and promotes the uniformity of the coating thickness, and enhances the bonding strength between the TaC coating and the transition layer and carbon matrix, thereby improving the surface density of the product.

[0052] 4. Phenolic resin, epoxy resin, and silane coupling agent are introduced into the slurry simultaneously. During the spraying stage, the cross-linking strength between the slurry and the substrate is improved, ensuring the uniformity of the coating thickness. During the CVD deposition and sintering stages, while ensuring the bonding strength of each component, the resin undergoes a series of structural transformations such as carbonization and graphitization. This provides space for the filling of pyrolytic carbon generated by CVD deposition and the thermal expansion of other components, thus solving the problem of mismatch in thermal expansion of each component.

[0053] 5. The TaC-coated carbon parts prepared by this invention have better corrosion resistance and thermal shock resistance, and a longer service life. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] The present invention will be further described below with reference to embodiments.

[0056] The manufacturers and models of the raw materials used in the examples and comparative examples are as follows:

[0057] Carbon-carbon composite material sample, VU-CC, Hangzhou Woken New Material Technology Co., Ltd., density 1.50 g / cm³ 3 ;

[0058] Graphite powder (800 mesh), Shenzhen Hanhui Graphite Co., Ltd.

[0059] Graphite powder (1000 mesh), Shenzhen Hanhui Graphite Co., Ltd.;

[0060] Phenolic resin PF7203, Jinan Shengquan Group Co., Ltd.;

[0061] Phenolic resin PF6908, Jinan Shengquan Group Co., Ltd.;

[0062] Epoxy Resin AG-80, Yixin Chemical New Materials;

[0063] γ-aminopropyltriethoxysilane, KH550, Jinan Yuno Chemical Co., Ltd.;

[0064] TaC powder, TaC-3 from Hunan Huasheng Technology Co., Ltd.

[0065] Boron oxide powder, Jinan Yuno Chemical Co., Ltd. (YN);

[0066] N-Phenylanomethyltriethoxysilane, KH-ND42, Hangzhou Jessica Chemical Co., Ltd.;

[0067] Isostatically pressed graphite sample, Hangzhou Woken New Material Technology Co., Ltd., VU-G-OF.

[0068] (I) Implementation Examples

[0069] Example 1

[0070] A TaC coating on the surface of a carbon material and its preparation method, comprising the following steps:

[0071] S1, with a density of 1.30 g / cm³ 3 Carbon-carbon composite material samples were placed in an ultrasonic bath, completely submerged in distilled water, and washed for 10-30 minutes to obtain clean, water-containing carbon-carbon samples. These samples were then placed in a dust-free oven and heated from room temperature to 150°C at a rate of 2°C / min, maintaining this temperature at 150°C for 3-4 hours to obtain dry, clean carbon-carbon samples. These clean carbon-carbon samples were then purified at 2500°C in a purification furnace to obtain high-purity carbon-carbon samples.

[0072] S2. A transition layer slurry is prepared from 800-mesh graphite powder, phenolic resin PF7203, epoxy resin AG-80, anhydrous ethanol, distilled water, and γ-aminopropyltriethoxysilane in a weight ratio of 3:5:1:6:22:0.002. It includes the following steps:

[0073] 1) When preparing the transition layer slurry, first dissolve the phenolic resin PF7203 in the anhydrous ethanol and stir thoroughly to obtain a uniformly dissolved concentrated solution of phenolic resin.

[0074] 2) Slowly add the distilled water to the concentrated phenolic resin solution and continue stirring until fully dissolved and homogeneous to obtain a dilute phenolic resin solution with a mass concentration of approximately 16.13%.

[0075] 3) Add the epoxy resin AG-80 to the dilute phenolic resin solution, stir and dissolve evenly to obtain a resin mixture solution.

[0076] 4) Add the γ-aminopropyltriethoxysilane to the resin mixture and stir until homogeneous.

[0077] 5) Finally, add the 800-mesh graphite powder to the above solution and stir evenly to obtain the transition layer slurry.

[0078] S3. After uniformly spraying the transition layer slurry onto the surface of the high-purity carbon substrate, reverse the direction every 10 minutes to air dry for 1 hour, then place it in an oven and heat it to 80°C at a heating rate of 5°C / min for 15 minutes, then heat it to 180°C at a heating rate of 2°C / min for 180 minutes to cure the transition layer slurry and obtain the transition layer coated part.

[0079] S4. A surface layer slurry is prepared from TaC powder, boron oxide powder, phenolic resin PF6908, anhydrous ethanol, distilled water, and γ-aminopropyltriethoxysilane in a weight ratio of 5:0.002:15:15:40:0.001. It includes the following steps:

[0080] 1) When preparing the surface layer slurry, first dissolve the phenolic resin PF6908 in the anhydrous ethanol and stir thoroughly to obtain a uniformly dissolved concentrated solution of phenolic resin.

[0081] 2) Slowly add the distilled water to the concentrated phenolic resin solution and continue stirring until fully dissolved and homogeneous to obtain a phenolic resin solution with a mass concentration of approximately 21.43%.

[0082] 3) Add the γ-aminopropyltriethoxysilane to the phenolic resin solution and stir until homogeneous.

[0083] 4) Finally, mix the TaC powder and boron oxide powder evenly, add them to the above solution, and stir thoroughly to obtain the surface layer slurry.

[0084] S5. After the surface layer slurry is uniformly sprayed onto the surface of the transition layer coated part, the surface layer slurry is cured in the same way as in step S3 to obtain the preliminary coated part.

[0085] S6. Place the pre-coated part into the CVD furnace and operate according to the following process:

[0086] 1) First step: Evacuate the furnace to a pressure of 0.3 kPa;

[0087] 2) Second step: Purge the furnace with nitrogen until the pressure reaches 80±10 kPa;

[0088] 3) Third step: Adjust the nitrogen flow rate and vacuum pump opening to maintain the furnace pressure at 80±10KPa;

[0089] 4) Step 4: Heat the room temperature to 500℃ for 120 minutes, with a furnace pressure of 80±10KPa;

[0090] 5) Fifth step: 500℃, constant temperature for 30 minutes, furnace pressure 80±10KPa;

[0091] 6) Step 6: Increase the temperature from 500℃ to 800℃ for 90 minutes, with a furnace pressure of 80±10KPa;

[0092] 7) Step 7: Maintain temperature at 800℃ for 30 minutes, and furnace pressure at 80±10KPa;

[0093] 8) Step 8: Increase the temperature from 800℃ to 1000℃ for 90 minutes, with a furnace pressure of 80±10KPa;

[0094] 9) Step 9: 1000℃, constant temperature for 120 min, furnace pressure 80±10KPa;

[0095] 10) Step 10: Turn off the nitrogen gas, continue to evacuate until the furnace pressure is maintained at 0.3-0.5 kPa, and raise the temperature from 1000℃ to 1050℃ for 30 minutes;

[0096] 11) Step 11: After mixing nitrogen and propane at a ratio of 10:1, the mixture is introduced into the CVD furnace. The vacuum pump is kept running continuously, the furnace pressure is 0.9-1.0 kPa, and the temperature is kept constant at 1050±10℃ for 1500 min.

[0097] 12) Step 12: Turn off propane, continue to purge with nitrogen, keep the vacuum pump running, maintain furnace pressure at 0.5-0.6 kPa, and keep the temperature constant at 1050 ± 10℃ for 60 min;

[0098] 13) Step thirteen: Turn off the heating, continue to purge with nitrogen, keep the vacuum pump running, maintain the furnace pressure at 0.5-0.6 kPa, and begin cooling;

[0099] 14) Step fourteen: Cool down to 500℃, increase nitrogen flow rate, keep the vacuum pump running, keep the furnace pressure at 80-90KPa, and continue cooling;

[0100] 15) Step 15: Cool down to below 100℃, turn off the vacuum pump, purge with nitrogen to adjust the furnace pressure to normal pressure, then turn off the nitrogen, open the furnace cover, and complete the preliminary carbonization of the coated parts to obtain the coated carbonized parts.

[0101] S7. Place the coated carbonized parts into the sintering furnace and operate according to the following process:

[0102] 1) First step: Evacuate to 50-80 Pa;

[0103] 2) Second step: Heat the room temperature to 500℃ for 90 minutes, with a furnace pressure of 50-80Pa;

[0104] 3) Third step: 500℃, constant temperature for 10 minutes, furnace pressure 50-80Pa;

[0105] 4) Fourth step: Increase the temperature from 500℃ to 1000℃ for 100 minutes, with a furnace pressure of 50-80Pa;

[0106] 5) Fifth step: 1000℃, constant temperature for 30 minutes, furnace pressure 50-80Pa;

[0107] 6) Step 6: Increase the temperature from 1000℃ to 1500℃ for 120 minutes, with a furnace pressure of 50-80Pa;

[0108] 7) Step 7: 1500℃, constant temperature for 30 minutes, furnace pressure 50-80Pa;

[0109] 8) Step 8: Increase the temperature from 1500℃ to 2000℃ for 150 minutes, with a furnace pressure of 50-80Pa;

[0110] 9) Step Nine: 2000℃, constant temperature for 60 minutes, furnace pressure 50-80Pa;

[0111] 10) Step 10: Increase the temperature from 2000℃ to 2400℃ for 180 minutes, with a furnace pressure of 50-80Pa;

[0112] 11) Step 11: 2400℃, constant temperature for 60 min, furnace pressure 50-80 Pa;

[0113] 12) Step 12: At 2400℃, purge with 0.35m of argon gas. 33 / min, furnace pressure 1700±200Pa, sintering 300min;

[0114] 13) Step thirteen: Turn off the argon gas, evacuate to 50-80 Pa, turn off the heating, and begin cooling;

[0115] 14) Step fourteen: Cool down to below 50℃, turn off the vacuum pump, purge with nitrogen to atmospheric pressure and then turn off the nitrogen, open the furnace lid and take out the sample.

[0116] The above steps are used to complete the sintering of the coated carbon part, resulting in a carbon-carbon sample with a uniform and dense TaC coating. The thickness of the TaC coating is 120 micrometers, the thickness of the transition layer is 50 micrometers, and the thickness of the surface layer is 70 micrometers.

[0117] Example 2

[0118] The method described in Example 1 was followed, except that the transition layer slurry components were replaced with 1000-mesh graphite powder, phenolic resin PF7203, epoxy resin AG-80, anhydrous ethanol, distilled water, and γ-aminopropyltriethoxysilane in a weight ratio of 5:5:1:5:25:0.003.

[0119] Example 3

[0120] The procedure was carried out according to the method in Example 1, except that the γ-aminopropyltriethoxysilane in the transition layer slurry and the surface layer slurry was replaced with N-phenylaminomethyltriethoxysilane in equal amounts.

[0121] Example 4

[0122] The procedure was carried out according to the method in Example 1, except that the carbon-carbon composite sample was replaced with an isostatically pressed graphite sample.

[0123] The method described in Example 1 was followed, except that the transition layer slurry components were replaced with 1000-mesh graphite powder, phenolic resin PF7203, epoxy resin AG-80, anhydrous ethanol, distilled water, and γ-aminopropyltriethoxysilane in a weight ratio of 2:8:2:8:24:0.005.

[0124] The method described in Example 1 was followed, except that the surface layer slurry components were replaced with TaC powder, boron oxide powder, phenolic resin PF6908, anhydrous ethanol, distilled water, and γ-aminopropyltriethoxysilane in a weight ratio of 5:0.003:15:15:35:0.005.

[0125] Example 5

[0126] The procedure was carried out according to the method in Example 4, except that the γ-aminopropyltriethoxysilane in the transition layer slurry and the surface layer slurry was replaced with N-phenylaminomethyltriethoxysilane in equal amounts.

[0127] Comparative Example 1

[0128] The procedure was carried out according to the method in Example 1, except that the carbon samples were not subjected to ultrasonic cleaning and high-temperature purification.

[0129] Specifically: Step S1 is missing.

[0130] Comparative Example 2

[0131] The procedure was carried out according to the method in Example 1, except that no transition layer slurry was sprayed and cured.

[0132] Specifically, steps S2 and S3 are missing.

[0133] Comparative Example 3

[0134] The procedure was carried out according to the method in Example 1, except that phenolic resin PF7203, epoxy resin AG-80 and γ-aminopropyltriethoxysilane were not added to the transition layer slurry.

[0135] Specifically, the transition layer slurry is made from 800-mesh graphite powder, anhydrous ethanol, and distilled water in a weight ratio of 3:6:22.

[0136] Comparative Example 4

[0137] The procedure was carried out according to the method in Example 4, except that the isostatic graphite samples were not subjected to ultrasonic cleaning and high-temperature purification.

[0138] Specifically: Step S1 is missing.

[0139] Comparative Example 5

[0140] The procedure was carried out according to the method in Example 4, except that no transition layer slurry was sprayed and cured.

[0141] Specifically, steps S2 and S3 are missing.

[0142] Comparative Example 6

[0143] The procedure was carried out according to the method in Example 4, except that phenolic resin PF7203, epoxy resin AG-80 and γ-aminopropyltriethoxysilane were not added to the transition layer slurry.

[0144] Specifically, the transition layer slurry is composed of 1000-mesh graphite powder, anhydrous ethanol, distilled water, and a mixture in a weight ratio of 2:8:24.

[0145] Comparative Example 7

[0146] The procedure was carried out according to the method in Example 1, except that boron oxide powder was not added to the surface layer slurry.

[0147] Comparative Example 8

[0148] The procedure was carried out according to the method in Example 4, except that boron oxide powder was not added to the surface layer slurry.

[0149] (II) Performance Testing

[0150] To evaluate the coating effects and corrosion resistance in silicon vapor of the samples from Examples 1-5 and Comparative Examples 1-8, relevant tests were conducted on the prepared samples. The main test items and methods are as follows:

[0151] (1) Coating condition: Visually inspect the coating surface for bulges or cracks;

[0152] (2) Porosity: Tested according to GB / T24529-2009 Determination of Apparent Porosity of Carbon Materials;

[0153] (3) Corrosion resistance: First, the silicon material was placed in a graphite crucible, and each sample was placed on top of the graphite crucible. The crucible was then covered, allowing silicon vapor to contact the sample on one side only. The crucible was then placed in a test furnace, and the temperature was increased to 1600℃ at a rate of 5℃ / min and held for 100h. High-purity argon gas was used for protection throughout the experiment. After cooling and removal from the furnace, the bending strength of the samples was tested according to GB / T40398.2-2021 Test Methods for Carbon-Carbon Composite Materials Part 2: Bending Performance Test. After the silicon material melts, a large amount of silicon vapor is generated, which diffuses to the surface of the carbon material and causes a silanization reaction, thereby reducing the mechanical properties of the sample.

[0154] The experimental results are shown in Table 1 below:

[0155] Table 1

[0156]

[0157] Referring to Examples 1 and 2, it can be seen that using 1000-mesh graphite powder as the transition layer component results in a product with lower porosity, higher flexural strength, better corrosion resistance, and longer service life compared to 800-mesh graphite powder. Referring to Examples 1 and 3, and further referring to Examples 4 and 5, it can be seen that γ-aminopropyltriethoxysilane and N-phenylaminomethyltriethoxysilane have no significant impact on the material composition.

[0158] Referring to Example 1 and Comparative Example 1, and referring to Example 4 and Comparative Example 4, it can be seen that the cleanliness of the substrate has a significant impact on the stability of the coating. The higher the purity of the substrate, the better the coating coverage, the lower the porosity of the sample, and the stronger the corrosion resistance.

[0159] Referring to Example 1 and Comparative Example 2, and referring to Example 4 and Comparative Example 5, it can be seen that the transition layer slurry provides a buffer for the difference in thermal expansion coefficients between the TaC coating and the carbon substrate, reducing problems such as cracking and peeling of the TaC coating, significantly slowing down the rate of performance degradation, and improving corrosion resistance.

[0160] Referring to Example 1 and Comparative Example 3, and referring to Example 4 and Comparative Example 6, it can be seen that phenolic resin, epoxy resin, and silane coupling agent improve the crosslinking strength between the slurry and the substrate in the coating, thus alleviating the problem of coating peeling.

[0161] Referring to Example 1 and Comparative Example 7, and referring to Example 4 and Comparative Example 8, it can be seen that boron oxide powder acts as a sintering agent in the coating, reducing surface porosity and improving corrosion resistance.

[0162] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a TaC coating on the surface of a carbon material, characterized in that, It includes the following steps: (1) Pre-treat the carbon substrate to obtain a high-purity carbon substrate; (2) Mix 2-5 parts graphite powder, 5-10 parts phenolic resin, 1-2 parts epoxy resin, 5-8 parts anhydrous ethanol, 21-32 parts distilled water and 0.002-0.005 parts silane coupling agent by weight to obtain a transition layer slurry; after uniformly spraying the transition layer slurry onto the surface of the high-purity carbon substrate, cure it at 180-200℃ to obtain a transition layer; (3) Mix 1-5 parts by weight of TaC powder, 0.001-0.003 parts by weight of boron oxide powder, 14-18 parts by weight of phenolic resin, 10-15 parts by weight of anhydrous ethanol, 33-45 parts by weight of distilled water and 0.001-0.005 parts by weight of silane coupling agent to obtain a surface layer slurry; after uniformly spraying the surface layer slurry onto the surface of the transition layer, cure it at 180-200℃ to obtain a surface layer; (4) A carbon material with a TaC coating is obtained through a deposition and sintering process; during the deposition process, under the conditions of a deposition temperature of 1050-1200℃ and a vacuum degree of 900-1000Pa, nitrogen gas and propane gas are mixed at a flow rate ratio of 5-20:1 and then sintered at a speed of 0.2-0.5m. 3 Deposition was carried out at a rate of 0.3-0.4 m / min for 20-30 h; during the sintering process, the temperature was kept constant for 30-60 min at 2000-2500℃ and a vacuum degree of 50-80 Pa, followed by deposition at a rate of 0.3-0.4 m / min. 3 Argon gas is introduced at a rate of / min, and the vacuum degree after argon gas introduction is 1500-2000Pa. Sintering continues for 4-5 hours.

2. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, In step (1), carbon substrate pretreatment: the carbon substrate is placed in an ultrasonic bath pot, and after cleaning the surface stains and dust, it is dried and then purified at high temperature of 2500℃ in a purification furnace to obtain high-purity carbon substrate.

3. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, In steps (2) and (3), the curing time is 3-5 hours.

4. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, The graphite powder is 800-1000 mesh high-purity flake graphite powder with a carbon content ≥99.99%.

5. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, The silane coupling agent is γ-aminopropyltriethoxysilane or N-phenylaminomethyltriethoxysilane.

6. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, The TaC powder has a particle size of 0.5-1.5 μm and a purity greater than 99.99%.

7. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, The boron oxide powder has a particle size of 2500 mesh and a purity greater than 99.9%.

8. The method for preparing a TaC coating on a carbon material surface according to claim 1, characterized in that, The thickness of the TaC coating is 30-120 micrometers.

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