Carbon-carbon composites, carbon-ceramic composites and anti-oxidation coatings, aircraft brake discs

Abstract

The present invention relates to the field of carbon-carbon composite materials, and discloses a carbon-carbon composite material, a carbon-ceramic composite material, an anti-oxidation coating, and an aircraft brake disc. The anti-oxidation coating comprises components by weight: 150 parts of an aqueous solution of aluminum dihydrogen phosphate with a content of 37-43%, 70-130 parts of tin powder, 60-120 parts of silicon carbide powder, 15-60 parts of glass powder with a softening point of 600°C-900°C, 15-50 parts of kaolin, and 10-30 parts of boron carbide powder. The anti-oxidation coating can form a coating with good thermal stability and chemical stability by accurately proportioning and mixing a plurality of materials, and can protect the carbon-carbon composite material from oxidation under a high temperature environment.

Description

Technical Field

[0001] The invention relates to the field of carbon-carbon composite materials, and in particular to a carbon-carbon composite material, a carbon-ceramic composite material, an anti-oxidation coating, and an aircraft brake disc. Background Art

[0002] Carbon / carbon composite materials have the characteristics of low density, high temperature resistance, large specific heat capacity, good thermal conductivity, excellent friction and wear performance, and not easy to stick and lock. They have achieved great success in the field of civil aircraft brakes and have gradually replaced powder metallurgy brake discs. However, carbon / carbon composite materials also have some disadvantages, such as oxidation above 370°C, and the oxidation rate is relatively fast when it exceeds 450°C. The temperature of the brake disc reaches 600-800°C when the aircraft lands normally. The mechanical strength of carbon / carbon composite materials decreases significantly after oxidation. In order to ensure the safe use of the aircraft brake disc within the normal service life, it is necessary to carry out effective oxidation protection treatment on the non-friction surface of the aircraft brake disc.

[0003] Phosphate anti-oxidation coating is simple to prepare. Phosphate solution has good bonding force with carbon / carbon composite materials, and evenly covers the surface of carbon / carbon composite materials, especially the punctured pores on the surface of carbon fiber preforms. Phosphate solution has a good protective effect below 800°C. Boron-containing compounds such as boron, boron carbide, titanium diboride, zirconium diboride, and hafnium diboride have good high-temperature protection effects, but the water resistance of borides is poor. After high-temperature oxidation, boron-containing compounds form boron oxide, which reacts with water to produce boric acid, which is volatile and destroys the coating. Aircraft carbon / carbon composite protective coatings usually adopt a composite coating mode to maximize the anti-oxidation effect; the bottom layer is a phosphate coating, and the outer layer is a boron-containing coating; the processing process is usually complicated, with multiple coatings and multiple heat treatments. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a carbon-carbon composite material, a carbon-ceramic composite material, an anti-oxidation coating, and an aircraft brake disc. By accurately proportioning a plurality of materials, including aluminum dihydrogen phosphate, tin powder, silicon carbide powder, glass powder, kaolin and boron carbide powder, and mixing the above components, a coating with good thermal stability and chemical stability can be formed, which can protect the carbon-carbon composite material from oxidation in a high temperature environment.

[0005] In order to solve the above technical problems, a first aspect of an embodiment of the present invention provides a carbon-carbon composite material anti-oxidation coating, wherein the anti-oxidation coating comprises components in parts by weight:

[0006] 150 parts of 37-43% aluminum dihydrogen phosphate aqueous solution, 70-130 parts of tin powder, 60-120 parts of silicon carbide powder, 15-60 parts of glass powder with a softening point of 600℃-900℃, 15-50 parts of kaolin and 10-30 parts of boron carbide powder.

[0007] Furthermore, the glass powder is borosilicate glass powder.

[0008] Furthermore, the anti-oxidation coating also includes: 0 to 15 parts of boron powder.

[0009] Accordingly, a second aspect of an embodiment of the present invention provides a carbon-carbon composite material, the surface of which is coated with the above-mentioned anti-oxidation coating;

[0010] The carbon-carbon composite material is kept warm at a first preset temperature for a first preset time after being coated with the anti-oxidation coating.

[0011] Further, the first preset temperature is 300°C;

[0012] The first preset duration is 1h~2h.

[0013] Correspondingly, a third aspect of an embodiment of the present invention provides a carbon-ceramic composite material, the surface of which is coated with the above-mentioned anti-oxidation coating.

[0014] Correspondingly, a fourth aspect of an embodiment of the present invention provides an aircraft brake disc, wherein the material of the aircraft brake disc is the above-mentioned carbon-carbon composite material or the above-mentioned carbon-ceramic composite material.

[0015] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0016] By precisely proportioning a variety of materials, including aluminum dihydrogen phosphate, tin powder, silicon carbide powder, glass powder, kaolin and boron carbide powder, and mixing the above ingredients, a coating with good thermal and chemical stability can be formed, which can protect carbon-carbon composites from oxidation in high-temperature environments. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0018] A first aspect of an embodiment of the present invention provides a carbon-carbon composite anti-oxidation coating, the anti-oxidation coating comprising components in parts by weight:

[0019] 150 parts of aluminum dihydrogen phosphate aqueous solution with a content of 37-43%, 70-130 parts of tin powder, 60-120 parts of silicon carbide powder, and glass with a softening point of 600°C-900°C provide a carbon-carbon composite material anti-oxidation coating, the anti-oxidation coating includes parts by weight

[0020] 15-60 parts of powder, 15-50 parts of kaolin and 10-30 parts of boron carbide powder.

[0021] The present invention uses phosphate solution as the basis and adds glass powder, silicon carbide powder, boron carbide powder, boron powder, tin powder and the like with different softening points to improve the anti-oxidation performance of the coating. After one coating and one heat treatment, the anti-oxidation performance of the coating can be achieved at 700°C for more than 10 hours.

[0022] Aqueous solution of aluminum dihydrogen phosphate is an excellent binder. In the coating system, it can bind various solid powder particles (such as tin powder, silicon carbide powder, etc.) together; when the coating is prepared, aluminum dihydrogen phosphate will form a continuous bonding phase during the drying and curing process, making the coating structure more compact. In addition, aluminum dihydrogen phosphate can form a stable phosphate structure under high temperature. This structure can resist the erosion of corrosive media such as oxygen and water vapor in the oxidizing atmosphere. For example, in the anti-oxidation coating on the surface of carbon-carbon composite materials, the phosphate structure formed by aluminum dihydrogen phosphate can prevent oxygen from directly contacting the carbon-carbon composite matrix, playing a dual role of physical barrier and chemical protection. When the coating is used in a high temperature environment, aluminum dihydrogen phosphate can maintain the relative stability of its structure. It will not decompose rapidly or lose its bonding properties due to high temperature, thereby ensuring that the coating can still play a protective role under high temperature oxidation conditions. For example, in the protective coating of some high-temperature furnace equipment, aluminum dihydrogen phosphate can maintain the integrity of the coating at a higher temperature to prevent the substrate material from being oxidized.

[0023] Tin powder can be used as an antioxidant in the coating, forming a thin protective film on the surface of the coating. When oxidizing substances such as oxygen come into contact with the coating, tin will react with oxygen first. For example, during the oxidation process, tin is oxidized to tin oxide (SnO or SnO 2 ), these oxidation products will cover the surface of the coating, preventing oxygen from further diffusing into the coating and the substrate, playing a sacrificial protective role. Tin powder can improve the density of the coating. Since the tin powder particles are filled between other powder particles, the pores and defects in the coating can be reduced, making the entire structure tighter, and the hardness and wear resistance of the coating can be improved, so that the coating is not easily damaged when subjected to external mechanical friction or other physical effects, thereby better exerting its anti-oxidation function. In some special application scenarios, such as those where electrostatic discharge is required, the presence of tin powder can give the coating a certain conductivity. This is because tin is a good conductor. It can form a conductive path inside the coating, conduct away static electricity and other charges in a timely manner, and avoid charge accumulation from damaging the coating and substrate. It also helps to improve the stability of the coating.

[0024] The coating is applied once and heat treated once, and the treatment temperature can be low, with good anti-oxidation effect and high water resistance. The coating process can not only be used for oxidation protection of aircraft brake discs and repair of uncoated parts, but also for oxidation protection of carbon ceramic brake discs.

[0025] The above heat treatment can be directly applied after the surface of the carbon / carbon composite material is coated with an anti-oxidation coating and then treated in an oven. The treatment process is based on a temperature of 250° C. to 300° C. and insulation for 1 to 3 hours.

[0026] Optionally, glass powders with different softening points are used to achieve gradual curing and performance optimization of the coating at different temperature stages. The first softening point glass powder (e.g., 700°C) and the second softening point glass powder (e.g., 900°C) begin to soften at lower and higher temperatures respectively, and a protective layer can be formed in stages during the heating process.

[0027] At a lower temperature (700°C), the first softening point glass powder begins to soften and forms a preliminary protective layer. As the temperature continues to rise, the second softening point glass powder (900°C) begins to soften, further enhancing the density and stability of the protective layer. Phased protection can better prevent the oxidation of carbon-carbon composite materials at high temperatures. Glass powders with different softening points can better bond with the substrate during heating and improve the adhesion of the coating. By adjusting the ratio of the two glass powders, the physical properties of the coating, such as thermal expansion coefficient, hardness, and wear resistance, can be adjusted to adapt to different application environments and requirements. The protective layer formed by glass powders with different softening points at high temperatures can provide better chemical stability and resist the erosion of corrosive gases.

[0028] Furthermore, the anti-oxidation coating also includes: 0 to 15 parts of boron powder.

[0029] The purpose of adding boron powder to the anti-oxidation coating is to utilize the unique physical and chemical properties of boron powder to improve the anti-oxidation and anti-ablation capabilities of the coating. Boron powder forms boron oxides (such as B 2 O 3 ) has a low melting point and is easy to flow and fill the pores in the coating, preventing direct contact between oxygen and the material and reducing the occurrence of oxidation reactions. The addition of boron powder can also improve the process performance of the coating, such as improving the fluidity and adhesion of the coating, making it easier to form a uniform coating on the surface of the carbon-carbon composite material.

[0030] The present invention will now describe the preparation process of the above-mentioned anti-oxidation coating with reference to several embodiments. Embodiment 1

[0031] The composition of the anti-oxidation coating: 150 grams of aluminum dihydrogen phosphate aqueous solution with a content of 37-43%, 25 milliliters of water, 1 milliliter of non-ionic surfactant OP-4, 50 grams of tin powder, 60 grams of silicon carbide powder, 30 grams of glass powder with a softening point of 700°C, 20 grams of kaolin, 15 grams of boron carbide powder, and 2 grams of boron powder.

[0032] Preparation process: Add the above powder into aluminum dihydrogen phosphate aqueous solution, stir evenly, then add 1 ml of OP-4 and stir evenly again.

[0033] The coating is applied on the surface of the carbon-carbon composite material or the surface of the carbon-ceramic composite material.

[0034] Heat treatment process: Place the coated carbon-carbon composite sample in an oven, heat from room temperature to 250°C, and keep it warm for 2 hours. Embodiment 2

[0035] The composition of the anti-oxidation coating: 150 grams of aluminum dihydrogen phosphate aqueous solution with a content of 37-43%, 30 milliliters of water, 1 milliliter of non-ionic surfactant Span-80, 90 grams of tin powder, 80 grams of silicon carbide powder, 10 grams of glass powder with a softening point of 650°C, 30 grams of glass powder with a softening point of 900°C, 15 grams of kaolin, 10 grams of boron carbide powder, and 8 grams of boron powder.

[0036] Preparation process: Add the above powder into aluminum dihydrogen phosphate aqueous solution, stir evenly, then add 1 ml of Span-80 and stir evenly again.

[0037] The coating is applied on the surface of the carbon-carbon composite material or the surface of the carbon-ceramic composite material.

[0038] Heat treatment process: Place the coated carbon-carbon composite sample in an oven, heat from room temperature to 300°C, and keep it warm for 1 hour. Embodiment 3

[0039] The composition of the anti-oxidation coating: 150 grams of aluminum dihydrogen phosphate aqueous solution with a content of 37-43%, 30 milliliters of water, 1 milliliter of non-ionic surfactant Tween-80, 100 grams of tin powder, 60 grams of silicon carbide powder, 40 grams of glass powder with a softening point of 850°C, 30 grams of kaolin, 10 grams of boron carbide powder, and 2 grams of boron powder.

[0040] Preparation process: Add the above powder into aluminum dihydrogen phosphate aqueous solution, stir evenly, then add 1 ml of Tween-80 and stir evenly again.

[0041] The coating is applied on the surface of the carbon-carbon composite material or the surface of the carbon-ceramic composite material.

[0042] Heat treatment process: Place the coated carbon-ceramic composite sample in an oven, heat from room temperature to 300°C, and keep it warm for 2 hours.

[0043] The above-mentioned anti-oxidation coating can be used for oxidation protection of the non-friction surface of aircraft carbon / carbon composite brake discs. It is also suitable for local repair of damaged or missed coatings on the non-friction surface of aircraft carbon / carbon composite brake discs. It can also be used for oxidation protection of the non-friction surface of carbon-ceramic composite brake discs and brake pads.

[0044] Correspondingly, a second aspect of an embodiment of the present invention provides a carbon-carbon composite material, the surface of which is coated with the above-mentioned anti-oxidation coating; after being coated with the anti-oxidation coating, the carbon-carbon composite material is kept warm at a first preset temperature for a first preset time in a normal environment.

[0045] Furthermore, the first preset temperature is 300° C.; the first preset time is 1 h to 2 h.

[0046] After the anti-oxidation coating is applied to the surface of the carbon-carbon composite material, the process of keeping the temperature at the first preset temperature for the first preset time is mainly to allow the coating material to fully solidify and form a stable protective layer. This process is crucial to improving the high temperature stability and anti-oxidation performance of the carbon-carbon composite material.

[0047] Through the insulation process, the pores and defects in the coating can be reduced, forming a denser structure, which helps to block the penetration of oxygen and water vapor, thereby improving the material's antioxidant properties. The insulation process can also promote thermal stability reactions in the coating, such as the formation of certain ceramic phases, which can remain stable at high temperatures, thereby improving the overall thermal stability of carbon-carbon composites. By precisely controlling the insulation temperature and time, the physical and chemical properties of the coating, such as hardness, wear resistance, thermal expansion coefficient, etc., can be optimized to adapt to different application environments and requirements.

[0048] Accordingly, a third aspect of an embodiment of the present invention provides a carbon-ceramic composite material, the surface of which is coated with the above-mentioned anti-oxidation coating. The anti-oxidation coating is coated on the surface of the carbon-ceramic composite material to further improve its performance in a high temperature environment, especially its oxidation resistance and thermal shock resistance. The above-mentioned carbon-ceramic composite material can be applied to brake materials, aerospace, sealing materials, conductive materials and many other aspects.

[0049] Correspondingly, a fourth aspect of an embodiment of the present invention provides an aircraft brake disc, wherein the material of the aircraft brake disc is the above-mentioned carbon-carbon composite material or the above-mentioned carbon-ceramic composite material.

[0050] Aircraft brake discs using the above carbon-carbon composite material or the above carbon-ceramic composite material are lighter than traditional metal brake discs and maintain performance under extremely high temperatures. The operating temperature of the brake disc can be as high as over 2000°C. The above materials have high specific heat capacity and thermal conductivity and can effectively absorb and dissipate the heat generated during braking.

[0051] The embodiment of the present invention aims to protect a carbon-carbon composite material, a carbon-ceramic composite material, an anti-oxidation coating, and an aircraft brake disc, wherein the anti-oxidation coating comprises components by weight: 150 parts of a 37-43% aqueous solution of aluminum dihydrogen phosphate, 70-130 parts of tin powder, 60-120 parts of silicon carbide powder, 15-60 parts of glass powder with a softening point of 600°C-900°C, 15-50 parts of kaolin, and 10-30 parts of boron carbide powder. The above technical solution has the following effects:

[0052] The above-mentioned anti-oxidation coating is formed by accurately mixing multiple materials, including dihydrogen aluminum phosphate, tin powder, silicon carbide powder, glass powder, kaolin and boron carbide powder. By mixing the above-mentioned ingredients, a coating with good thermal stability and chemical stability can be formed, which can protect the carbon-carbon composite material from oxidation in a high temperature environment.

[0053] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. An anti-oxidation coating, characterized in that: The anti-oxidation coating comprises components in parts by weight: 150 parts of 37-43% aluminum dihydrogen phosphate aqueous solution, 70-130 parts of tin powder, 60-120 parts of silicon carbide powder, 15-60 parts of glass powder with a softening point of 600°C-900°C, 15-50 parts of kaolin and 10-30 parts of boron carbide powder; It also includes: 0 to 15 parts of boron powder, and the content of boron powder is not 0.

2. The anti-oxidation coating according to claim 1, characterized in that: The glass powder is borosilicate glass powder.

3. A carbon-carbon composite material, characterized in that: The surface of the carbon-carbon composite material is coated with the anti-oxidation coating as claimed in claim 1 or 2; The carbon-carbon composite material is kept warm at a first preset temperature for a first preset time after being coated with the anti-oxidation coating.

4. The carbon-carbon composite material according to claim 3, characterized in that: The first preset temperature is 250°C-300°C; The first preset duration is 1h~3h.

5. A carbon-ceramic composite material, characterized in that: The surface of the carbon-ceramic composite material is coated with the anti-oxidation coating as claimed in claim 1 or 2.

6. An aircraft brake disc, characterized in that: The material of the aircraft brake disc is the carbon-carbon composite material as claimed in claim 3 or 4 or the carbon-ceramic composite material as claimed in claim 5.