Method for repairing surface damage of si c high temperature oxidation resistant coating of c / c composite material and application thereof

Abstract

The application relates to a repairing method for surface damage of a SiC high-temperature oxidation-resistant coating of a C / C composite material. First, the damaged part of the SiC coating on the surface of the C / C composite material is pretreated, that is, the damaged part is polished along the damaged direction, the surface of the damaged part is treated to be more flat, and the damaged part is facilitated to be repaired, then the embedding infiltration method and the slurry brushing-oxidation method are selected to repair. The preparation method is simple, the process is stable, the repeatability is high, and the method is expected to be applied in large-scale engineering. After oxidation test is conducted on the repaired composite material, it is found that the mass loss of the repaired composite material is reduced by 74.36% compared with the damaged sample, and is reduced by 1% compared with the undamaged sample, which indicates that the method can effectively repair the damaged oxidation-resistant coating, can restore the oxidation protection performance of the damaged sample, and can even exceed the undamaged level, can improve the thermal protection performance of the damaged C / C composite material, can greatly reduce the use cost of the C / C composite material, can prolong the service life of the C / C composite material component, and conforms to the green energy-saving concept.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of protective coatings, and relates to a repairing method for surface damage of a SiC high-temperature oxidation-resistant coating of C / C composite material and application. BACKGROUND

[0002] Carbon / carbon (C / C) composite material is an advanced composite material in which carbon fibers reinforce a carbon matrix. The material is often used as a thermal protection component such as a throat liner and a blade of an aircraft, and is an important candidate material in the fields of aerospace and other high-tech fields, because it has low density, low thermal expansion coefficient, high thermal conductivity, and high-temperature mechanical properties that do not decrease but increase with temperature. However, the material is easily oxidized in a high-temperature oxygen-containing environment, which leads to a sharp decrease in mechanical properties and seriously limits the wide application of C / C composite material components. An effective way to solve this problem is to prepare an oxidation-resistant ceramic coating on the surface of the C / C composite material, so as to improve the oxidation resistance of the C / C composite material by completely isolating the C / C composite material from the oxygen-containing environment. SiC ceramic is often used as an oxidation-resistant coating material for C / C composite material because of its good physicochemical compatibility with the C / C composite material. However, the C / C composite material SiC coating is often damaged on the surface during transportation and use, and the use cost of the entire component will be increased if the damaged coating is directly replaced or even discarded. Therefore, it is urgent to develop a technology for repairing the damaged SiC coating of the C / C composite material.

[0003] Document 1 "Influence of the preparation temperature on the phase, microstructure and anti-oxidation property of a SiC coating for C / C composites, Jian Feng Huang, Xie Rong Zeng, Hejun Li, XinBo Xiong, YeWei Fu, Carbon 2004, 42: 1517-1521" discloses that a SiC coating is prepared on the surface of a C / C composite material by a pack cementation method, and a C / C composite material with an excellent SiC coating is prepared. It is shown that SiC ceramic is the first choice for an oxidation-resistant coating of a C / C composite material.

[0004] Document 2 "Repair of SiC coating on carbon / carbon composites by laser cladding technique, Han Hui Wang, Hejun Li, Xiaohong Shi, Xuesong Liu, Jing'an Kong, Hang Zhou, Ceramics International, 2020, 46: 19537-19544." discloses repairing the SiC coating on the surface of C / C composites by laser cladding technique, but the oxidation weight loss rate of the repaired sample after oxidation at 1500℃ for 10h is as high as 10.5%, and the repair efficiency needs to be improved. SUMMARY

[0005] In order to solve the problems in the prior art, the present application provides a method for repairing surface damage of a SiC high-temperature oxidation-resistant coating of a C / C composite material. The method uses an embedding infiltration method and a slurry brushing-oxidation method to repair damaged areas of the SiC coating on the surface of the C / C composite material, thereby repairing the damaged SiC coating using a Si-SiC coating and achieving the goal of greatly extending the service life of the SiC coating C / C composite material.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a method for repairing surface damage of a SiC high-temperature oxidation-resistant coating of a C / C composite material, comprising the following steps:

[0007] Determine the damaged coating damage area and clean it to obtain a pretreated workpiece;

[0008] Weigh Si powder with a mass percentage of 60%-80%, C powder with a mass percentage of 12%-16%, and Al2O3 powder with a mass percentage of 4%-12% and mix them evenly as the repair powder for the embedding infiltration method; then weigh Si powder with a mass percentage of 25%-35%, Al2O3 powder with a mass percentage of 2.5%-3.5%, and SiC powder with a mass percentage of 61.5%-72.5% as the slurry powder, and put the slurry powder into a silica sol solution with a mass percentage of 5%-10% to prepare a slurry as the slurry for the slurry brushing-oxidation method;

[0009] The obtained pre-processed workpiece is wrapped in the obtained embedding infiltrating method repair powder, the pre-processed workpiece wrapped by the embedding infiltrating method repair powder is placed in a heating furnace, and the furnace is heated to 1600-2200℃ under an inert atmosphere, and the temperature is kept for 1-4h, and then the furnace is cooled to room temperature, and an embedding infiltrating method initial repair workpiece is obtained; the obtained brushing-oxidation method repair slurry is brushed on the damaged part of the initial repair workpiece; the initial repair workpiece after brushing the brushing-oxidation method repair slurry is placed in a heat treatment furnace and heat treated at 1400-1500℃ for 15-45min, and then it is taken out and air cooled to obtain a repaired workpiece.

[0010] Further, the damaged area of the SiC coating surface of the C / C composite material is determined by visual inspection, the damaged area is polished, the edge area is transitioned, the pre-processed C / C composite material is cleaned with ultrasonic deionized water and dried for standby.

[0011] Further, the polishing treatment is manual polishing with a file and the C / C composite material substrate is exposed.

[0012] Further, the particle size of 60%-80% Si powder, 10%-20% C powder and 4%-8% Al2O3 powder is 300-800 mesh.

[0013] Further, the Si powder, C powder and Al2O3 powder are mechanically mixed by ball milling.

[0014] Further, the particle size of the Si powder, Al2O3 powder and SiC powder in the slurry powder is 300-800 mesh.

[0015] Further, the brushing-oxidation method repair slurry is brushed on the damaged part of the initial repair workpiece to be flush with the surrounding surface.

[0016] Further, the weight ratio of the slurry powder to the silica sol solution is 1:2.

[0017] Further, the heating rate is 3-7℃ / min.

[0018] The application of the above-mentioned repair method repairs the mechanical damage of the SiC high-temperature oxidation-resistant coating surface of the C / C composite material.

[0019] Compared with the prior art, the present application has at least the following beneficial effects: the C / C composite SiC high-temperature oxidation-resistant coating surface damage repairing method provided by the present application is based on the embedding infiltration method and the slurry brushing-oxidation method, and the Si-SiC system is used to repair the damaged area of the SiC coating C / C composite material; the Si-SiC repairing system used is close to the thermal expansion coefficients of the C / C composite material substrate and the original SiC coating, which can greatly reduce the risk of cracks and other defects caused by the large difference in thermal expansion coefficients during preparation and use. The embedding infiltration method can provide a certain oxidation-resistant basis for the slurry brushing-oxidation method after pretreatment of the sample, so as to avoid oxidation of the C / C substrate during subsequent slurry brushing-oxidation repair; the slurry brushing-oxidation method can increase the coating thickness of the repaired area, control the coating thickness of the repaired area to be close to the original coating thickness, and on the other hand, can fill the cracks and holes and other defects generated during the preparation of the coating by the embedding infiltration method, so as to make the coating more dense.

[0020] The embedding infiltration method and the slurry brushing-oxidation method are very mature and have high repeatability, and are expected to be applied in large-scale engineering. It is found through oxidation evaluation that the weight loss of the repaired sample is only 0.75% after oxidation at 1500 DEG C for 10h, the mass loss is reduced by 74.36% compared with the damaged sample, and is reduced by 1% compared with the undamaged sample, the oxidation resistance of the repaired sample is greatly improved compared with the previous methods for repairing the SiC coating of the C / C composite material, and even exceeds the undamaged level, which greatly prolongs the service life of the C / C composite material, saves the use cost, and meets the green and energy-saving concept. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The macroscopic photograph of the pretreated damaged sample.

[0022] Figure 2 (a) is the weight loss curve of the 1500 DEG C oxidation for 10h of the inventive examples 1, 2, 3, the comparative examples 1, 2, 3, the damaged sample and the undamaged sample; Figure 2 (b) is Figure 2 (a) is a local enlarged view of (a). DETAILED DESCRIPTION

[0023] The present application will be further described in combination with the embodiments and the drawings:

[0024] Example 1:

[0025] 1) Pretreatment of damaged coating: determine the damaged area of the C / C composite SiC coating, polish the area, ultrasonic clean the pretreated sample and dry for standby.

[0026] 2) Powder preparation: Si powder with mass percentage of 77%, C powder with mass percentage of 15%, and Al2O3 powder with mass percentage of 8% were mixed uniformly by ball milling to obtain the powder for the embedding and infiltrating method; then Si powder with mass percentage of 25%, Al2O3 powder with mass percentage of 2.5%, and SiC powder with mass percentage of 72.5% were mixed to obtain the slurry powder, which was placed in a silica sol solution with mass percentage of 6% to obtain the slurry for the slurry brushing and oxidation method.

[0027] 3) Damage repair: the sample obtained in step 1) was wrapped in the powder for the embedding and infiltrating method obtained in step 2), and the sample wrapped in the powder was placed in a muffle furnace and heated to 2100°C under an argon atmosphere, and then kept at 2100°C for 2 h, and then cooled to room temperature to obtain the initial sample repaired by the embedding and infiltrating method; the mixed slurry powder for the slurry brushing and oxidation method obtained in step 2) was brushed on the damaged part of the initial repair workpiece; the sample after brushing was placed in a high-temperature oxidation furnace and heated to 1450°C, and then heat-treated for 30 min, and then taken out and air-cooled to obtain the repaired sample.

[0028] 4) Oxidation test: the high-temperature oxidation furnace was heated to 1500°C, and the repaired sample, the unrepaired sample, and the undamaged sample were placed in the high-temperature oxidation furnace for oxidation test, and after oxidation for 10 h, the weight loss of the repaired sample was 0.75%, the weight loss of the unrepaired sample was 75.11%, and the weight loss of the undamaged sample was 1.75%.

[0029] Example 2:

[0030] 1) Damage coating pretreatment: the damaged area on the surface of the SiC coating of the C / C composite material was determined, and the area was polished; the pretreated sample was ultrasonically cleaned and dried for standby.

[0031] 2) Powder preparation: Si powder with mass percentage of 77%, C powder with mass percentage of 15%, and Al2O3 powder with mass percentage of 8% were mixed uniformly by ball milling to obtain the powder for the embedding and infiltrating method; then Si powder with mass percentage of 25%, Al2O3 powder with mass percentage of 2.5%, and SiC powder with mass percentage of 72.5% were mixed to obtain the slurry powder, which was placed in a silica sol solution with mass percentage of 6% to obtain the slurry for the slurry brushing and oxidation method.

[0032] 3) Damage Repair: The sample obtained in step 1) is wrapped in the embedding and infiltration repair powder obtained in step 2). The sample wrapped in the embedding and infiltration repair powder is placed in a muffle furnace and heated to 2100℃ in an argon atmosphere, held for 2 hours, and then cooled to room temperature in the furnace to obtain the initial sample for embedding and infiltration repair. The uniformly mixed slurry obtained in step 2) is applied to the damaged area of ​​the initial sample for embedding and infiltration repair. The high-temperature oxidation furnace is heated to 1400℃, and the coated sample is placed in the high-temperature oxidation furnace for heat treatment for 30 minutes. Then it is taken out and air-cooled to obtain the repaired sample.

[0033] 4) Oxidation test: The high-temperature oxidation furnace was heated to 1500℃. The repaired sample, the unrepaired sample, and the undamaged sample were placed in the high-temperature oxidation furnace for oxidation test. After 10 hours of continuous oxidation, the weight loss of the repaired sample was 2.28%, the weight loss of the unrepaired sample was 75.11%, and the weight loss of the undamaged sample was 1.75%.

[0034] Example 3:

[0035] 1) Damaged coating pretreatment: Determine the damaged area on the surface of the SiC coating of C / C composite material, grind the area, and then ultrasonically clean and dry the pretreated sample for later use.

[0036] 2) Powder preparation: Weigh 77% Si powder, 15% C powder and 8% Al2O3 powder by mass and ball-mill them evenly to prepare the powder for the embedding and infiltration method repair. Then weigh 35% Si powder, 3.5% Al2O3 powder and 61.5% SiC powder by mass to prepare the slurry powder. Place the slurry powder in a 6% silica sol solution to prepare a slurry as the raw material for the slurry coating-oxidation method repair.

[0037] 3) Damage Repair: The sample obtained in step 1) is wrapped in the embedding and infiltration repair powder obtained in step 2). The sample wrapped in powder is placed in a muffle furnace and heated to 2100℃ in an argon atmosphere, held for 2 hours, and then cooled to room temperature in the furnace to obtain the initial sample for embedding and infiltration repair. The uniformly mixed slurry-oxidation repair powder obtained in step 2) is applied to the damaged area of ​​the initial repair workpiece. The high-temperature oxidation furnace is heated to 1500℃, and the coated sample is placed in the furnace for heat treatment for 30 minutes. Then it is taken out and air-cooled to obtain the repaired sample.

[0038] 4) Oxidation test: The high-temperature oxidation furnace was heated to 1500℃. The repaired sample, the unrepaired sample, and the undamaged sample were placed in the high-temperature oxidation furnace for oxidation test. After 10 hours of continuous oxidation, the weight loss of the repaired sample was 12.37%, the weight loss of the unrepaired sample was 75.11%, and the weight loss of the undamaged sample was 1.75%.

[0039] Comparative Example 1

[0040] 1) Damage coating pretreatment: Determine the damaged area of the SiC coating surface of the C / C composite material, polish the area, ultrasonic clean and dry the pretreated sample for standby.

[0041] 2) Powder preparation: Take 77% Si powder, 15% C powder and 8% Al2O3 powder by mass percentage, mix uniformly by ball milling as the raw material for embedding infiltration repair standby; then take 40% Si powder, 4% Al2O3 powder and 56% SiC powder by mass percentage as the slurry powder, put the slurry powder into a 6% silicon sol solution to prepare the slurry as the raw material for slurry brushing-oxidation repair standby.

[0042] 3) Damage repair: wrap the sample obtained in step 1) in the embedding infiltration repair powder obtained in step 2), place the powder-wrapped sample in a muffle furnace, heat to 2100℃ in an argon environment, keep for 2h, then cool to room temperature with the furnace, obtain the embedding infiltration repair initial sample; brush the slurry brushing-oxidation repair powder obtained in step 2) on the damaged part of the initial repair sample; heat the sample to 1400℃ in a high-temperature oxidation electric furnace, place the brushed sample in the electric furnace for heat treatment for 30min, then take it out and air cool, obtain the repaired sample.

[0043] Oxidation test: heat the high-temperature oxidation electric furnace to 1500℃, place the repaired sample, the unrepaired sample and the undamaged sample into the high-temperature oxidation electric furnace for oxidation test, after 10h of continuous oxidation, the weight loss of the repaired sample is 20.81%, the weight loss of the unrepaired sample is 75.11%, and the weight loss of the undamaged sample is 1.75%. When the Si content in the slurry powder exceeds the range of 25%-35%, the repair effect is poor.

[0044] Comparative Example 2

[0045] 1) Damage coating pretreatment: Determine the damaged area of the SiC coating surface of the C / C composite material, polish the area, ultrasonic clean and dry the pretreated sample for standby.

[0046] 2) Powder preparation: Take 77% Si powder, 15% C powder and 8% Al2O3 powder by mass percentage, mix uniformly by ball milling as the raw material for embedding infiltration repair standby; then take 40% Si powder, 4% Al2O3 powder and 56% SiC powder by mass percentage as the slurry powder, put the slurry powder into a 6% silicon sol solution to prepare the slurry as the raw material for slurry brushing-oxidation repair standby.

[0047] 3) Damage repair: the sample obtained in step 1) is wrapped in the embedding infiltration method repair powder obtained in step 2), the sample after the powder is wrapped is placed in a muffle furnace, and the furnace is heated to 2100 DEG C under an argon atmosphere, and then the furnace is cooled to room temperature after being kept for 2 hours, so that an embedding infiltration method repair initial sample is obtained; the mixed and uniform slurry brushing-oxidation method repair powder obtained in step 2) is brushed on the damaged part of the initial repair sample; a high-temperature oxidation electric furnace is heated to 1350 DEG C, the sample after brushing is placed in the electric furnace for heat treatment for 30 minutes, and then the sample is taken out and air-cooled, so that a repaired sample is obtained.

[0048] 4) Oxidation test: a high-temperature oxidation electric furnace is heated to 1500 DEG C, the repaired sample, the unrepaired sample and the undamaged sample are placed in the high-temperature oxidation electric furnace for oxidation test, and after oxidation for 10 hours, the weight loss of the repaired sample is 52.62%, the weight loss of the unrepaired sample is 75.11%, and the weight loss of the undamaged sample is 1.75%. When the oxidation temperature is lower than 1400 DEG C, the repair effect is poor.

[0049] Comparative example 3:

[0050] 1) Damage coating pretreatment: the damaged area of the SiC coating surface of the C / C composite material is determined, and the area is polished. The pretreated sample is ultrasonically cleaned and dried for standby use.

[0051] 2) Powder preparation: Si powder with a mass percentage of 77%, C powder with a mass percentage of 15% and Al2O3 powder with a mass percentage of 8% are ball milled and uniformly mixed to serve as embedding infiltration method repair standby raw materials; then Si powder with a mass percentage of 40%, Al2O3 powder with a mass percentage of 4% and SiC with a mass percentage of 56% are weighed and mixed to serve as slurry preparation powder, and the slurry preparation powder is placed in a silicon sol solution with a mass percentage of 6% to prepare a slurry as slurry brushing-oxidation method repair standby raw materials.

[0052] 3) Damage repair: the sample obtained in step 1) is wrapped in the embedding infiltration method repair powder obtained in step 2), the sample after the powder is wrapped is placed in a muffle furnace, and the furnace is heated to 2100 DEG C under an argon atmosphere, and then the furnace is cooled to room temperature after being kept for 2 hours, so that an embedding infiltration method repair initial sample is obtained; the mixed and uniform slurry brushing-oxidation method repair powder obtained in step 2) is brushed on the damaged part of the initial repair sample; a high-temperature oxidation electric furnace is heated to 1350 DEG C, the sample after brushing is placed in the electric furnace for heat treatment for 30 minutes, and then the sample is taken out and air-cooled, so that a repaired sample is obtained.

[0053] 4) Oxidation test: The high-temperature oxidation furnace was heated to 1500℃, and the repaired sample, the unrepaired sample and the undamaged sample were put into the high-temperature oxidation furnace for oxidation test. After 10h of continuous oxidation, the weight loss of the repaired sample was 67.83%, the weight loss of the unrepaired sample was 75.11%, and the weight loss of the undamaged sample was 1.75%. When the Si content in the pulping powder exceeds the range of 25%-35%, the repair effect is poor.

Claims

1. A method for repairing surface damage of a SiC high-temperature oxidation-resistant coating of a C / C composite material, characterized in that, The method comprises the following steps: determining the damaged coating damage area and cleaning to obtain a pretreated workpiece; weighing Si powder with a mass percentage of 60%-80%, C powder with a mass percentage of 12%-16%, and Al2O3 powder with a mass percentage of 4%-12% to mix uniformly as embedding infiltration repair powder, wherein the total mass percentage of Si powder, C powder and Al2O3 powder is 100%; then weighing Si powder with a mass percentage of 25%-35%, Al2O3 powder with a mass percentage of 2.5%-3.5%, and SiC powder with a mass percentage of 61.5%-72.5% as pulp-making powder, and placing the pulp-making powder in a silicon sol solution with a mass percentage of 5%-10% to prepare a slurry as a slurry brushing-oxidation repair slurry; wrapping the obtained pretreated workpiece in the obtained embedding infiltration repair powder, placing the pretreated workpiece wrapped in the embedding infiltration repair powder in a heating furnace, heating the pretreated workpiece to 1600-2200 ℃ under an inert atmosphere, keeping the temperature for 1-4 h, then cooling the pretreated workpiece to room temperature to obtain an embedding infiltration repair initial repair workpiece; brushing the obtained slurry brushing-oxidation repair slurry on the damaged part of the initial repair workpiece; heating the initial repair workpiece brushed with the slurry brushing-oxidation repair slurry to 1400-1500 ℃ in a high-temperature oxidation electric furnace, and then taking the initial repair workpiece out of the high-temperature oxidation electric furnace and air cooling to obtain a repaired workpiece; determining the damaged area of the SiC coating of the C / C composite material by visual inspection, polishing the damaged area, and performing transition treatment on the edge area, and then cleaning and drying the pretreated C / C composite material with ultrasonic deionized water for standby.

2. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The polishing treatment is manual polishing with a file and exposing the C / C composite material substrate.

3. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The Si powder, C powder and Al2O3 powder are mechanically mixed by ball milling.

4. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The particle size of the Si powder, Al2O3 powder and SiC powder in the pulp-making powder is 300-800 mesh.

5. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The slurry brushing-oxidation repair slurry is brushed on the damaged part of the initial repair workpiece until the surface of the damaged part is flush with the surrounding surface.

6. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The weight ratio of the pulp-making powder to the silicon sol solution is 1:

2.

7. The method of claim 1, wherein the C / C composite SiC high-temperature oxidation-resistant coating surface damage repair method is characterized by: The heating rate is 3-7 ℃ / min.

8. Use of the repair method according to any one of claims 1 to 7, characterized in that: Repairing mechanical damage of a SiC high-temperature oxidation-resistant coating of a C / C composite material.

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