Rapid fabrication of C/SiC composites using rotating chemical vapor infiltration

Rotating chemical vapor infiltration (RCVI) is an improved process for fabricating C/SiC composites, and it is based on chemical vapor infiltration principle. In RCVI process, layer-by-layer of carbon cloth and deposition of matrix were done synchronously by rotating of a graphite axis, with the result that the bottle-neck effect of gas diffusion in traditional processes was eliminated. The effect of flux and concentration of methyltrichlorosilane (MTS, CHaSiCls), deposition temperature and rotational linear velocity of carbon cloth on deposition rate of siliconcarbide matrix, and the effect of deposition temperature on structure of silicon-carbide matrix, were studied with lots of experiments. Three different kinds of pores, which are micro-gap around filaments, macro-holes due to weaving and spaces between plies of carbon cloth, were rapidly filled with SiC matrix at the same time. The optimal conditions for deposition are a low pressure of 5kPa, a high temperature of 1100°C, 400 mL-min"1 and 200 mL-min"1 flow rates of H₂ and Ar, respectively, a MTS temperature of 40°C and a l.l-4S.Smm-min"1 rotational linear velocity of carbon cloth.