Thermal decomposition of methyltrichlorosilane/ hydrogen/ inert mixtures at conditions relevant for chemical vapor infiltration of SiC ceramics

Abstract

AbstractMethyltrichlorosilane (MTS) decomposition in a high‐temperature flow reactor was investigated at conditions favorable for silicon carbide (SiC) deposition in chemical vapor infiltration systems. Gas chromatography was used to determine the effects of temperature, residence time, and initial MTS‐H2‐N2 mixture composition on the gas‐phase chemistry. Four stable species were detected, including the evolution of MTS and three decomposition products: methane (CH4), trichlorosilane (SiHCl3), and silicon tetrachloride (SiCl4). The experimental data were used to assess the applicability of a recent detailed kinetic model proposed by Ge et al. for MTS decomposition. The model showed a much slower decomposition rate of MTS than that observed in experiments, requiring optimization of selected set of rate parameters. The optimized model was able to reasonably predict the experimental data for a range of parametric conditions explored. In addition, a principal component analysis–based model reduction approach was used to extract a skeletal reaction model with nearly half the number of species in the original model and with similar performance.