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

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 s olidified partially by liquid-phase impregnation with a resol-type cresol r esin. 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 dimethyldichlorosil ane. Thus an FCM with a continuous composition distribution was obtained. N o thermal cracks were observed and the compositionally gradient layer remai ned adhesive to the base composite following repeated rapid cooling tests f rom 1000 to 0 degrees C. (C) 1999 Elsevier Science Ltd. All rights reserved .