Studies on the effects of the concentration in the preparation of C/C composites by the CVI process of propane

Effects of the propane concentration in the preparation of C/C composites by the Chemical Vapor Infiltration (CVI) of propane were studied. The amount of deposited carbon and the compositions of the product gas were measured at 5, 10, 20, and 100% propane. Numerical simulations were also carried out. The rate of deposition increases slightly as time passes. The mathematical modeling of the system estimated well the experimental results with the deposition rate constant from the reference. The main product gases were methane, ethylene, and acetylene. In the product gas, the fraction of methane increases monotonously with the percentage of propane. As the percentage of propane increases, the fraction of ethylene gets small and those of methane and acetylene become big. As the reaction temperature gets high, the selectivity of methyl radicals decreases and that of ethyl radicals increases slightly.