1. A repairing agent for surface damage of a silicon carbide ceramic matrix composite is characterized by comprising solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers; the mass ratio of the components is 1: 1.2-1.8: 0.2-0.6: 0.8-1.5: 0.01-0.15.

2. A method for preparing the repairing agent for the damage of the surface layer of the silicon carbide ceramic matrix composite material as claimed in claim 1, wherein the method comprises the following steps: putting solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers in a mass ratio of 1: 1.2-1.8: 0.2-0.6: 0.8-1.5: 0.01-0.15 and zirconia ball milling beads into a sealed ball milling tank, and carrying out ball milling for 5-25 hours at a rotating speed of 50-120 r/min; and after the ball milling is finished, stirring for 30-45 min by adopting a magnetic stirrer at the rotating speed of 120-180 r/min.

3. A method for repairing the damage of the surface layer of the silicon carbide ceramic matrix composite by using the repairing agent for the damage of the surface layer of the silicon carbide ceramic matrix composite according to claim 1, which is characterized by comprising the following steps:

step 1, cleaning a damaged area: polishing the damaged area of the component by using a diamond file, ensuring that the surface of the damaged area has no unevenness, eliminating high points and performing smooth transition; wiping the damaged area with dust-free cloth soaked with ethanol to dry the area completely without visible dust and scum;

step 2, brushing a repairing agent: the repairing agent is uniformly coated on the damaged area, so that the sagging phenomenon cannot occur; after painting, slowly and repeatedly blowing the painted surface for no less than 30s under the condition of adjusting the temperature to be 100-150 ℃ until the surface of the repair area is not sticky; this step is repeated a number of times;

step 3, cleaning a repair area: after the repairing agent is completely cooled, polishing and grinding the brushing area, and ensuring that the brushing area and the adjoining area are in smooth transition without bulges or depressions caused by uneven brushing; then, lightly wiping the repair area by adopting dust-free cloth to remove dust and scum;

the service temperature range of the repairing layer is-120-1400 ℃.

4. The method of claim 3, wherein: and (3) fully drying: blowing the wiping area at 50-100 ℃ or standing for 5-10 min at room temperature in air.

5. The method of claim 3, wherein: and the step 2 is repeatedly executed for 2-5 times.

6. The method of claim 3, wherein: and 3, polishing and grinding the brushing area by 600-mesh sand paper.

Background

The silicon carbide ceramic matrix composite material represented by a continuous carbon fiber reinforced silicon carbide ceramic matrix composite material (C/SiC for short) and a continuous silicon carbide fiber reinforced silicon carbide ceramic matrix composite material (SiC/SiC for short) is one of main materials of a heat-proof structure for a hypersonic aircraft, an aerospace shuttle aircraft, a ramjet engine and a gas turbine engine. Because the material has certain brittleness, the component product prepared by the material has the possibility of causing surface coating falling off or surface layer damage such as fiber layer scratch and the like to the component due to various reasons after transportation, assembly, daily maintenance and repeated use, thereby influencing the heat-proof performance of the component. Meanwhile, the preparation cost of the silicon carbide ceramic matrix composite material member is high, the process period is long, and the whole scrapping of the member caused by surface layer damage greatly increases the development cost and period of the product. Therefore, a repair agent and a repair method which are simple and convenient to develop aiming at common surface damage of the silicon carbide ceramic matrix composite are needed.

Chinese patent No. CN111039698A discloses a method for repairing a thermal protective coating of a silicon carbide ceramic matrix composite member. According to the method, polycarbosilane, silicon carbide powder, a silicon-boron-carbon-nitrogen precursor and other reagents are mixed, and a bonding layer, a transition layer and a densified layer are sequentially prepared. The method needs heat treatment at high temperature for many times, and needs auxiliary shaping and curing. Therefore, the method needs more complicated heating equipment and shaping molds, and cannot realize on-site on-line repair of the component.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a repairing agent and a repairing method for the surface damage of a silicon carbide ceramic matrix composite, which overcome the problems of difficult repairing, poor manufacturability and long period of the surface damage of the ceramic matrix composite. Has the advantages of good repairing effect, strong manufacturability, low cost, convenient field operation and the like.

Technical scheme

A repairing agent for surface damage of a silicon carbide ceramic matrix composite is characterized by comprising solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers; the mass ratio of the components is 1: 1.2-1.8: 0.2-0.6: 0.8-1.5: 0.01-0.15.

A method for preparing the repairing agent for the surface damage of the silicon carbide ceramic matrix composite is characterized by comprising the following steps: putting solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers in a mass ratio of 1: 1.2-1.8: 0.2-0.6: 0.8-1.5: 0.01-0.15 and zirconia ball milling beads into a sealed ball milling tank, and carrying out ball milling for 5-25 hours at a rotating speed of 50-120 r/min; and after the ball milling is finished, stirring for 30-45 min by adopting a magnetic stirrer at the rotating speed of 120-180 r/min.

A method for repairing the surface damage of the silicon carbide ceramic matrix composite by using the repairing agent for the surface damage of the silicon carbide ceramic matrix composite is characterized by comprising the following steps:

step 1, cleaning a damaged area: polishing the damaged area of the component by using a diamond file, ensuring that the surface of the damaged area has no unevenness, eliminating high points and performing smooth transition; wiping the damaged area with dust-free cloth soaked with ethanol to dry the area completely without visible dust and scum;

step 2, brushing a repairing agent: the repairing agent is uniformly coated on the damaged area, so that the sagging phenomenon cannot occur; after painting, slowly and repeatedly blowing the painted surface for no less than 30s under the condition of adjusting the temperature to be 100-150 ℃ until the surface of the repair area is not sticky; this step is repeated a number of times;

step 3, cleaning a repair area: after the repairing agent is completely cooled, polishing and grinding the brushing area, and ensuring that the brushing area and the adjoining area are in smooth transition without bulges or depressions caused by uneven brushing; then, lightly wiping the repair area by adopting dust-free cloth to remove dust and scum;

the service temperature range of the repairing layer is-120-1400 ℃.

And (3) fully drying: blowing the wiping area at 50-100 ℃ or standing for 5-10 min at room temperature in air.

And the step 2 is repeatedly executed for 2-5 times.

And 3, polishing and grinding the brushing area by 600-mesh sand paper.

Advantageous effects

The invention provides a repairing agent and a repairing method for surface damage of a silicon carbide ceramic matrix composite, which are developed according to the physical properties and the surface damage characteristics of a silicon carbide ceramic matrix composite body and have low cost and easy operation. Because solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers are adopted in a reasonable proportion, a liquid substance with moderate viscosity is formed, and the repairing agent for on-site painting is realized. The chemical components of the repairing agent can form a repairing layer with good physical and chemical compatibility with the silicon carbide ceramic matrix composite material in a natural environment.

The preparation and construction process of the repairing agent does not need special equipment and high-temperature treatment, has strong manufacturability, and can be operated on line on the site of a damaged component. After the repairing agent is used for repairing surface damage, a repairing layer with good physical and chemical compatibility with the silicon carbide ceramic matrix composite body can be formed in a damaged area, and the repairing layer is high in bonding strength and high in temperature resistance. The reasonable repair process parameters and the reasonable proportion of the solid polycarbosilane, the dimethylbenzene, the zirconium carbide powder, the silicon carbide powder and the silicon carbide whisker are matched, so that the service temperature of the repair layer ranges from-120 ℃ to 1400 ℃, and can reach 1650 ℃ in a short time.

Drawings

FIG. 1 shows a step of repairing damage to the surface layer of the SiC ceramic matrix composite according to the present invention

FIG. 2 is a photograph of a silicon carbide ceramic matrix composite member with a plurality of skin damage.

FIG. 3 is a photograph of a SiC ceramic matrix composite member treated with the repairing agent and the repairing method of the present invention.

FIG. 4 is a photograph of a SiC ceramic matrix composite member subjected to 1600 ℃ high temperature plasma arc wind tunnel ablation for 600s after being treated by the repairing agent and the repairing method of the present invention.

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

the existing area of the surface of a certain continuous carbon fiber reinforced silicon carbide ceramic matrix composite material member is about 30 multiplied by 30mm²The surface coating of (a) is peeled off and the fiber preform fault thereof is visible to the naked eye, with a maximum damage depth of about 0.3 mm. The repairing steps are as follows:

step 1: and (4) preparing a repairing agent. Weighing solid polycarbosilane, xylene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers by a balance respectively, wherein the mass ratio of the solid polycarbosilane to the xylene to the zirconium carbide powder to the silicon carbide whiskers is 1:1.4:0.3:1: 0.1; putting solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide whiskers and zirconia ball grinding beads with the diameter of 8mm into a sealed ball-milling tank, and carrying out ball milling for 10 hours at the rotating speed of 80 r/min; taking out the ball-milled feed liquid into a reagent bottle, and continuously stirring the feed liquid by adopting a magnetic stirrer at the rotating speed of 120 revolutions per minute for later use.

Step 2: and cleaning the damaged area. Polishing the damaged area of the component by using a diamond file, ensuring that the surface of the damaged area has no unevenness, eliminating high points and performing smooth transition; wiping the damaged area with a dust-free cloth soaked with ethanol, standing at room temperature in air for 10min to confirm that there is no visible dust and scum.

And step 3: and (4) brushing a repairing agent. Dipping the repair agent to be used by a fine hair brush, and uniformly brushing the repair agent on the damaged area to confirm that no sagging phenomenon exists. After the painting is finished, a hand-held hot air gun is used for adjusting the temperature to 100 ℃, and the painting surface is slowly and repeatedly swept for 30 s. This step was repeated 3 times.

And 4, step 4: and cleaning the repair area. Polishing and grinding the brushing area by 600-mesh abrasive paper, ensuring that the brushing area is smoothly transited to an adjoining area and avoiding bulges or depressions caused by uneven brushing; and then, lightly wiping the repair area by using dust-free cloth to remove dust and scum. And finishing the repair.

Example 2:

the existing area of the surface of a certain continuous carbon fiber reinforced silicon carbide ceramic matrix composite material member is about 80 multiplied by 50mm²The surface coating of (2) is peeled off, and the maximum damage depth is about 0.15 mm. The repairing steps are as follows:

step 1: and (4) preparing a repairing agent. Weighing solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers by a balance respectively, wherein the mass ratio of the solid polycarbosilane to the dimethylbenzene to the zirconium carbide powder to the silicon carbide whiskers is 1:1.6:0.5:1.2: 0.02; putting solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide whiskers and zirconia ball grinding beads with the diameter of 8mm into a sealed ball-milling tank, and carrying out ball milling for 10 hours at the rotating speed of 80 r/min; taking out the ball-milled feed liquid into a reagent bottle, and continuously stirring the feed liquid by adopting a magnetic stirrer at the rotating speed of 100 revolutions per minute for later use.

Step 2: and cleaning the damaged area. Polishing the damaged area of the component by using a diamond file, ensuring that the surface of the damaged area has no unevenness, eliminating high points and performing smooth transition; wiping the damaged area with a dust-free cloth soaked with ethanol, standing at room temperature in air for 10min to confirm that there is no visible dust and scum.

And step 3: and (4) brushing a repairing agent. Dipping the repair agent to be used by a fine hair brush, and uniformly brushing the repair agent on the damaged area to confirm that no sagging phenomenon exists. After the painting is finished, a hand-held hot air gun is used for adjusting the temperature to 100 ℃, and the painting surface is slowly and repeatedly swept for 30 s. This step was repeated 2 times.

And 4, step 4: and cleaning the repair area. Polishing and grinding the brushing area by 600-mesh abrasive paper, ensuring that the brushing area is smoothly transited to an adjoining area and avoiding bulges or depressions caused by uneven brushing; and then, lightly wiping the repair area by using dust-free cloth to remove dust and scum. And finishing the repair.

Example 3:

the existing area of the surface of a certain continuous silicon carbide fiber reinforced silicon carbide ceramic matrix composite material member is about 20mm multiplied by 20mm²The surface coating of (2) is peeled off, and the maximum damage depth is about 0.3 mm. The repairing steps are as follows:

step 1: and (4) preparing a repairing agent. Weighing solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide powder and silicon carbide whiskers by a balance respectively, wherein the mass ratio of the solid polycarbosilane to the dimethylbenzene to the zirconium carbide powder to the silicon carbide whiskers is 1:1.5:0.3:1.5: 0.12; putting solid polycarbosilane, dimethylbenzene, zirconium carbide powder, silicon carbide whiskers and zirconia ball grinding beads with the diameter of 8mm into a sealed ball-milling tank, and carrying out ball milling for 20 hours at the rotating speed of 120 revolutions per minute; taking out the ball-milled feed liquid into a reagent bottle, and continuously stirring the feed liquid by adopting a magnetic stirrer at the rotating speed of 120 revolutions per minute for later use.

Step 2: and cleaning the damaged area. Polishing the damaged area of the component by using a diamond file, ensuring that the surface of the damaged area has no unevenness, eliminating high points and performing smooth transition; wiping the damaged area with a dust-free cloth soaked with ethanol, standing at room temperature in air for 10min to confirm that there is no visible dust and scum.

And step 3: and (4) brushing a repairing agent. Dipping the repair agent to be used by a fine hair brush, and uniformly brushing the repair agent on the damaged area to confirm that no sagging phenomenon exists. After the painting is finished, a hand-held hot air gun is used for adjusting the temperature to 100 ℃, and the painting surface is slowly and repeatedly swept for 30 s. This step was repeated 4 times.

And 4, step 4: and cleaning the repair area. Polishing and grinding the brushing area by 600-mesh abrasive paper, ensuring that the brushing area is smoothly transited to an adjoining area and avoiding bulges or depressions caused by uneven brushing; and then, lightly wiping the repair area by using dust-free cloth to remove dust and scum. And finishing the repair.