Analysis of the Process Influences on the Preparation of SiC Coatings by Chemical Vapor Deposition

Abstract

Silicon carbide (SiC) coatings prepared by chemical vapor deposition (CVD) are an ideal choice for oxidation-resistant coatings on surface of carbon-based materials，and the processes directly affect the deposition results of the coatings.In order to guide the process control of high-temperature oxidation-resistant SiC coatings on carbon/carbon (C/C) composites，a simulation model of the deposition furnace for preparing SiC coatings by the CVD method was established.Numerical simulations of the deposition process were conducted using computational fluid dynamics (CFD) software to investigate the effects of workpiece placement and key process parameters on the deposition results.Additionally，the influences of the main process parameters were quantified，and the combinations of process parameters were optimized.Results showed that the established finite element analysis model was reasonable and reliable.The placement and spacing of the workpieces were collaboratively affected by the deposition results.Within the range of process parameters，deposition uniformity was significantly impacted by temperature，with an influence degree of 28.39%.This was followed by pressure，with an influence degree of 13.90%，while the flow rate of the reactant methyltrichlorosilane (MTS) was found to have the least impact，at 6.43%.Furthermore，deposition uniformity was improved as temperature and pressure were decreased and the MTS flow rate was increased.Based on these influence patterns，process optimization revealed an increase in deposition uniformity of 102.45%.

Keywords

• chemical vapor deposition；silicon carbide；antioxidant；numerical simulation；process control