CARBON FIBER-REINFORCED CARBON COMPOSITE MATERIAL AND ITS PRODUCTION

摘要

PURPOSE:To provide the subject composite material having high strength and high oxidation resistance by forming a porous silicon carbide film on the surface of the subject composite material treated with silicon carbide for sealing and having a bulk density of >=a specified value and forming a chemical vapor deposition film of silicon carbide thereon. CONSTITUTION:Pore parts 2' of a carbon fiber-reinforced carbon composite material (C/C composite) 1 are impregnated with silicon carbide 2 preferably by the chemical vapor deposition method to make its bulk density >=1.85g/cm<3>. The above impregnated composite material is used as a substrate and the surface part of the substrate is subjected to the diffusion reaction method for conversion into silicon carbide so as to form a porous silicon carbide layer 3 followed by further formation of a silicon carbide layer 4 thereon using the chemical vapor deposition method. If the bulk density of the above-mentioned substrate is <1.85g/cm<3>, diffusion of the Si source for formation of silicon carbide into the central part of the C/C composite 1 during the diffusion reaction process can not be prevented effectively. In addition, the above-mentioned layer (modified layer) 3 can relieve thermal stress produced by the difference between the thermal expansion coefficient of the layer 4 and that of the C/C composite material 1.