Patent ID: 6627143
Filing Date: 2003-09-30
Classification: C04B,F16C,F16D,Y10T

Abstract:
A method for producing an SiCâ€”C/C composite material comprising silicon carbide, carbon fibers and a carbon component other than the carbon fibers and having a structure comprising a skeletal part and a matrix formed around the skeletal part, at least 50% of silicon carbide being of &bgr; type, the skeletal part being formed of carbon fibers and a carbon component other than the carbon fibers, silicon carbide capable of being present in a part of the skeletal part, the matrix being formed of silicon carbide, the matrix and the skeletal part being integrally formed, and the composite material having a porosity of 0.5-5% and a two-peak type distribution of average pore diameter, said method comprising a step of keeping metallic silicon and a molded body comprising a C/C composite or a C/C composite fired body in a furnace at a furnace inner temperature of 1100-1400Â° C. and under a furnace inner pressure of 0.1-10 hPa for 1 hour or more with flowing an inert gas in an amount of 0.1 NL or more per 1 kg of total weight of the molded body or the fired body and the metallic silicon, thereby reacting the carbon component constituting the matrix of the C/C composite with the metallic silicon to form a matrix comprising silicon carbide, a step of raising the furnace inner temperature to 1450-2500Â° C. with keeping the furnace inner pressure as it is, thereby melting and impregnating the metallic silicon into open pores of the molded body or the fired body to grow silicon carbide and simultaneously sufficiently filling the remaining pores with the metallic silicon, and a step of increasing the furnace inner pressure to about 1 atm with once reducing the furnace inner temperature to environmental temperature or keeping the furnace inner temperature as it is, and raising the furnace inner temperature to 2000-2800Â° C., whereby the produced silicon carbide is diffused from the matrix into the C/C composite composed of the carbon fibers and a carbon component other than carbon fibers and is reacted with the carbon.