Chemical vapor infiltration and deposition to produce a silicon carbide–carbon functionally gradient material

Abstract

Functionally gradient material (FGM) that had a layer in which the chemical composition changed gradually from C to SiC between the C/C composite and the surface SiC layer was prepared. The 3D-woven carbon fiber preform was solidified partially by liquid-phase impregnation with a resol-type cresol resin. The preform was further solidified by thermal-gradient chemical vapor infiltration of carbon from propane. A consistent compositionally gradient protective layer was prepared by chemical vapor deposition by changing the reactant mixture composition gradually from propane to dimethyldichlorosilane. Thus an FGM with a continuous composition distribution was obtained. No thermal cracks were observed and the compositionally gradient layer remained adhesive to the base composite following repeated rapid cooling tests from 1000 to 0°C.