Advanced composite materials are mainly resin based, metal based, Tao Ciji and carbon matrix composites, such as four categories, metal matrix composites have been used to push the compressor and fan blades of more than 10 of the engine, but the key components of high temperature can only be used in ceramic matrix composites and carbon fiber reinforced carbon matrix composites.
The former work temperature can be as high as 1650 degrees Celsius, while the carbon carbon composite material is more than 1650 degrees Celsius, especially more than 2000 degrees Celsius, the only candidate materials.
The application scope of carbon carbon composites has been expanding, as the anti ablation materials and high speed braking friction materials have been successfully applied in the field of aerospace.
The substantial problem of densification of carbon - carbon composites is "filling in holes" ". The density method of carbon carbon composites mainly include liquid phase impregnation method and chemical vapor infiltration method.
Carbon carbon composite material has a fatal problem need to be solved, or its potential will be unable to play, this is the C/C in the air above 400 degrees Celsius will be oxidized.
To solve the oxidation problem of carbon carbon composites mainly from two aspects,matrix modification and surface coating. The oxidation resistance of the substrate can be improved by modifying the oxidation resistance of the substrate, and the initial oxidation temperature of the carbon carbon composite material is increased from 400 to 800. The anti oxidation coating mainly has two kinds of technical routes, namely, diffusion method and CVI method.
The outstanding advantages of carbon / carbon composites are high strength, high specific modulus, high fracture toughness and excellent high temperature mechanical properties.