Carbon-carbon composite material surface damage repairing method and repairing material used based on photovoltaic thermal field

Abstract

The invention discloses a carbon-carbon composite material surface damage repairing method based on photovoltaic thermal field use and a repairing material, and relates to the technical field of carbon-carbon composite material surface repairing. The repair material comprises a primary repair material and a secondary repair material which are both composed of silicon powder, carbon powder and aluminum oxide powder, the primary repair material and a solvent are mixed to prepare slurry, the slurry is coated in a U-shaped groove of a carbon-carbon composite material, then the coated material is wrapped in the powder mixed with the repair material, an SIC coating is prepared in the argon atmosphere, and the SIC coating is used for repairing the surface of the carbon-carbon composite material. Finally, cleaning and drying are conducted, and preliminary repairing is completed; and mixing the secondary repair material with a solvent to prepare slurry, coating the slurry on the damaged part of the primarily repaired material, and performing high-temperature oxidation to complete repair. The heat treatment method and the slurry brushing-pre-oxidation method are combined, so that the damaged SiC coating on the surface of the carbon-carbon composite material is effectively repaired, the service life of the material is prolonged, and the use cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of surface damage repair of carbon-carbon composite materials, and specifically to a method and a repair material for surface damage repair of carbon-carbon composite materials based on photovoltaic thermal field. Background Art

[0002] At a time when the photovoltaic industry is booming, photovoltaic thermal field is a key link in the production process of monocrystalline silicon. As a crucible for the growth of monocrystalline silicon, C / C composite material crucibles need to withstand high temperature environments and erosion of silicon materials during the growth of monocrystalline silicon, and are important components to ensure the quality and production efficiency of monocrystalline silicon.

[0003] In the high temperature environment of single crystal silicon growth, silicon material will produce steam and react chemically with the surface of C / C composite crucible to generate silicon carbide (SiC), which gradually destroys the structure of the crucible surface, making the surface rough and even cracking and holes. In the actual operation of photovoltaic thermal field, C / C composite crucible will inevitably be mechanically damaged. For example, during the loading and unloading process, it may collide with other tools; during the installation and removal of the crucible, the surface may also be scratched due to improper operation. With the increase of usage time, the anti-oxidation coating on the surface of C / C composite crucible will gradually fail. Once the anti-oxidation performance decreases, the service life of the crucible will be greatly shortened, and it needs to be replaced frequently, which increases the production cost.

[0004] At present, the repair methods for the surface damage of C / C composite crucibles mainly include physical repair and chemical repair. Although the operation of physical repair methods such as filling and welding is relatively simple, the repair effect is often not ideal, and it is difficult to restore the original performance of the crucible surface. In addition, the bonding strength after repair is low, and it is easy to be damaged again. Chemical repair methods such as coating repair can improve the antioxidant properties of the crucible to a certain extent, but the bonding force between the coating and the substrate is not strong enough, and it is easy to peel off under high temperature and complex environment, which cannot effectively solve the problem of long-term use of the crucible.

[0005] In addition, the existing repair methods are costly, require expensive equipment and materials, and are complex in process and require high technical skills of operators. This makes the repair cost even close to or even exceeds the cost of replacing a new crucible, limiting its wide application in actual production. Summary of the invention

[0006] In response to the above technical problems, the present application solves the high cost problem of replacing the entire product due to surface damage of C / C composite materials during use in photovoltaic thermal fields, and prevents the continuous reduction in material strength due to untreated damage, thereby avoiding the collapse of the entire material system and ensuring the stable operation of the photovoltaic thermal field.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted in this application is: a method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field, comprising the following steps:

[0008] Step 1: sandblast the corroded part on the surface of the carbon-carbon composite material and grind out a U-shaped groove.

[0009] Step 2: First, ultrasonically clean the material and then dry it.

[0010] Step 3: Mix the preliminary repair material with a solvent to form a slurry, apply it to the U-shaped groove of the carbon-carbon composite material, and then wrap the coated material in a powder mixed with the repair material to prepare a SIC coating under an argon atmosphere. Finally, wash and dry it to complete the preliminary repair.

[0011] Step 4: Mix the secondary repair material with a solvent to prepare a slurry, apply it to the damaged area of ​​the material after the initial repair, and oxidize it at high temperature to complete the repair.

[0012] Preferably, the ultrasonic cleaning in step 2 must be carried out in anhydrous ethanol, the cleaning time is 30 minutes, the drying temperature is 70 degrees Celsius, and the drying time is 10 hours.

[0013] Preferably, the ambient temperature of the argon atmosphere in step three is 2273K, and the preparation time is 3 hours.

[0014] Preferably, the cleaning temperature in step three is 80 degrees Celsius and the drying time is 10 hours.

[0015] Preferably, in step 4, the high temperature oxidation environment is air, the temperature is 1400-1500 degrees Celsius, and the reaction time is 30 minutes.

[0016] A repair material for a method for repairing surface damage of a carbon-carbon composite material used in a photovoltaic thermal field, the repair material comprising a primary repair material and a secondary repair material, the primary repair material being a mixture of silicon powder, carbon powder and aluminum oxide powder, using anhydrous ethanol as a solvent, the secondary repair material being a mixture of silicon powder, aluminum oxide powder and silicon carbide powder, using a silica sol solution as a solvent.

[0017] Preferably, the powder mixing ratio of the preliminary repair material is 80 parts of silicon, 15 parts of aluminum oxide, and 5 parts of silicon carbide.

[0018] Preferably, the powder mixing ratio of the secondary repair material is 30 parts of silicon, 3 parts of aluminum oxide, and 67 parts of silicon carbide.

[0019] Compared with the prior art, the technical solution provided by this application has the following beneficial effects:

[0020] 1. The present invention can effectively repair the defects on the surface of C / C composite materials caused by high-temperature silicon vapor corrosion, mechanical damage, etc., and restore the integrity of the material surface.

[0021] 2. The present invention adopts secondary repair to increase the thickness of the coating in the repaired area, controls the thickness of the coating in the repaired area to be close to the thickness of the original coating, and significantly improves the oxidation resistance of the coating, which can effectively prevent the further oxidation of the C / C composite material in a high-temperature aerobic environment and extend the service life of the material in the photovoltaic thermal field.

[0022] 3. The present invention avoids a significant reduction in material strength caused by damage by repairing the damage, maintains the mechanical properties of the C / C composite material, and ensures its normal use in the photovoltaic thermal field.

[0023] 4. The method of the present invention is easy to operate, has a simple and easy-to-control process, is low in cost, and is suitable for large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the surface damage repair method of carbon-carbon composite materials. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0027] Embodiment 1:

[0028] A method for repairing surface damage of a carbon-carbon composite material based on a photovoltaic thermal field uses a repair material including a primary repair material and a secondary repair material. The primary repair material is formed by mixing silicon powder, carbon powder and aluminum oxide powder in a ratio of 80 parts of silicon, 15 parts of aluminum oxide and 5 parts of silicon carbide, and anhydrous ethanol is used as a solvent to prepare a slurry. The secondary repair material is formed by mixing silicon powder, aluminum oxide powder and silicon carbide powder in a ratio of 30 parts of silicon, 3 parts of aluminum oxide and 67 parts of silicon carbide, and a silica sol solution is used as a solvent to prepare the slurry.

[0029] Embodiment 2:

[0030] A carbon-carbon composite material matrix used in photovoltaic thermal field was prepared and pretreated and mechanical damage was simulated as a repair test sample.

[0031] First, the density is precisely selected to reach 1.65g / cm 3 The C / C composite material is used as the core matrix material. It is cut into precise dimensions of 15×10×5mm using high-precision cutting equipment. 3 The rectangle is then carefully polished with 300-grit sandpaper to ensure that the edges and corners are rounded and the surface is smooth, providing good base conditions for subsequent coating preparation.

[0032] The coating is prepared by an advanced embedding infiltration method. Raw materials are weighed in a specific proportion, with silicon powder accounting for 80% by weight, carbon powder for 15% by weight, and alumina powder for 5% by weight. After the three are fully mixed, they are placed in a special reaction vessel, and heated to 2273K in a highly protected atmosphere of high-purity argon gas. This high temperature state is maintained for 3 hours to cause the raw materials to undergo complex chemical reactions on the surface of the C / C composite material, generating a dense SiC coating with excellent performance in situ.

[0033] After the coating preparation is completed, in order to simulate the mechanical damage in actual working conditions, professional sandblasting equipment is used to finely sandblast the surface of the SiC-coated C / C composite material. Parameters such as sandblasting intensity and particle size have been strictly debugged to ensure that a representative damage morphology is formed on the surface of the material. Subsequently, a U-shaped defect with a depth of 0.3mm and a width of 3mm is carefully polished in the damaged area using precision grinding tools. Finally, ultrasonic cleaning is carried out in anhydrous ethanol for 30 minutes, and then dried at 70°C for 10 hours for subsequent repair process research.

[0034] The damaged coating is initially repaired by heat treatment. During repair, the raw materials are mixed again in a ratio of 80% by weight of silicon powder, 15% by weight of carbon powder, and 5% by weight of alumina powder, and anhydrous ethanol is used as an efficient solvent to prepare a uniform and stable slurry. After adding anhydrous ethanol to the mixed raw materials, place them in a strong stirring device and continue stirring at a specific speed for 8 hours to ensure that all components are fully dispersed and dissolved to form a slurry with good fluidity and coating properties. Next, use a fine brushing tool to carefully apply the slurry to the pre-prepared U-shaped defect to ensure uniform coating thickness and no bubbles remain.

[0035] After coating, the sample is quickly wrapped with ball-milled mixed powder in all directions, and is also placed in a high-temperature furnace to react for 3 hours in a pure argon atmosphere at 2273K. The sample that has been previously coated with slurry and dried is placed in the middle of the above-mentioned ball-milled mixed powder, so that the ball-milled mixed powder completely surrounds the sample from all directions. When reacting in an argon atmosphere at 2273K, the ball-milled mixed powder can interact with the slurry on the surface of the sample and the sample itself, which helps to promote the formation of SiC-coated C / C composite materials, and protects the sample and assists the reaction, making the reaction more complete and uniform, thereby obtaining better repair effects and material properties. In this process, the ball-milled mixed powder plays a key role in assisting the reaction and promoting the densification of the coating at high temperature, and finally obtains a SiC-coated C / C composite material with preliminary repair and significantly improved structural properties.

[0036] The secondary repair of the damaged coating adopts the pre-oxidation method of slurry brushing. Re-adjust the proportion of repair materials, accurately weigh 30% by weight of silicon powder, 3% by weight of aluminum oxide powder and 67% by weight of silicon carbide powder, and select 8% by weight of silica sol solution as solvent to prepare high-performance slurry. Silica sol solution not only serves as a dispersion medium, but the silicon component it contains also plays a unique role in subsequent reactions. After adding the mixed raw materials to the silica sol solution, place it in a professional stirring device and stir it continuously for 8 hours. During this period, strictly control parameters such as temperature and stirring speed to ensure the uniformity and stability of the slurry.

[0037] Use a soft, fine brush to evenly and carefully apply the prepared slurry to the pre-treated parts of the initial repair sample to ensure complete coverage and consistent thickness of the coating. Then, place the sample in a special high-temperature oxidation furnace and react accurately for 30 minutes in an air atmosphere at 1450°C. During this process, the air atmosphere promotes a moderate oxidation reaction on the surface of the material, and cooperates with the components in the slurry to further optimize the coating structure, and finally successfully obtains a fully repaired sample with excellent coating performance, meeting the stringent material use requirements.

[0038] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field, characterized in that The following steps are involved: Step 1: sandblast the corroded part of the carbon-carbon composite material surface and grind out a U-shaped groove; Step 2: First, ultrasonically clean the material and then dry it; Step 3: Mix the preliminary repair material with a solvent to form a slurry, apply it to the U-shaped groove of the carbon-carbon composite material, and then wrap the coated material in a powder mixed with the repair material to prepare a SIC coating under an argon atmosphere, and finally wash and dry it to complete the preliminary repair; Step 4: Mix the secondary repair material with a solvent to prepare a slurry, apply it to the damaged area of ​​the material after the initial repair, and oxidize it at high temperature to complete the repair.

2. The method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field according to claim 1, characterized in that: The ultrasonic cleaning in step 2 must be carried out in anhydrous ethanol, the cleaning time is 30 minutes, the drying temperature is 70 degrees Celsius, and the drying time is 10 hours.

3. The method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field according to claim 1, characterized in that: The ambient temperature of the argon atmosphere in step 3 is 2273 K, and the preparation time is 3 hours.

4. The method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field according to claim 1, characterized in that: The cleaning temperature in step 3 is 80 degrees Celsius and the drying time is 10 hours.

5. The method for repairing surface damage of carbon-carbon composite materials based on photovoltaic thermal field according to claim 1, characterized in that: In step 4, the high temperature oxidation environment is air, the temperature is 1400-1500 degrees Celsius, and the reaction time is 30 minutes.

6. A repair material for use in a method for repairing surface damage of a carbon-carbon composite material used in a photovoltaic thermal field according to any one of claims 1 to 5, characterized in that: The repair material includes a primary repair material and a secondary repair material. The primary repair material is a mixture of silicon powder, carbon powder and aluminum oxide powder, using anhydrous ethanol as a solvent. The secondary repair material is a mixture of silicon powder, aluminum oxide powder and silicon carbide powder, using a silica sol solution as a solvent.

7. The repair material for a carbon-carbon composite material surface damage repair method based on photovoltaic thermal field according to claim 1, characterized in that: The powder mixing ratio of the preliminary repair material is 80 parts of silicon, 15 parts of aluminum oxide, and 5 parts of silicon carbide.

8. The repair material for a method for repairing surface damage of a carbon-carbon composite material based on a photovoltaic thermal field according to claim 1, characterized in that: The powder mixing ratio of the secondary repair material is 30 parts of silicon, 3 parts of aluminum oxide, and 67 parts of silicon carbide.

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