Composite material of discontinuous silicon carbide particles and

Abstract

Dense, strong, composite materials are produced from mixtures of silicon and silicon carbide. The composite materials are characterized by a mixture of finely-divided silicon carbide in a substantially continuous matrix of silicon. The composite materials contain from about 40 to about 60 percent by volume silicon carbide and from about 60 to about 40 percent by volume silicon. The composite materials are produced by initially producing a finely-divided silicon carbide starting component and forming the component into a green body of the desired shape. The green body is subsequently impregnated with molten silicon in the absence of any substantial amount of carbon. Suitably, a thermoplastic resin binder may be added to the silicon carbide starting material to aid in forming the green body. The impregnation step may be carried out by surrounding the green body with finely-divided silicon metal and heating the covered body to a temperature above the melting point of silicon. The composite materials described have flexural strength of over about 90,000 psi at 1100.degree. C., elastic modulus of about 38 million psi at room temperature, are essentially non-porus and have densities ranging from about 2.6 to about 2.8 g/cc.