CVD法制备SiC涂层的工艺影响分析

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

化学气相沉积(CVD)法制备的碳化硅(SiC)涂层是碳基材料表面防氧化涂层的理想选择,各项工艺直接影响涂层的沉积结果。为指导碳/碳(C/C)复合材料高温抗氧化SiC涂层的工艺调控,建立了CVD法制备SiC涂层的沉积炉仿真模型,采用计算流体力学软件对沉积结果进行数值模拟研究,探究了工件摆放和主要工艺参数对沉积结果的影响,量化了主要工艺参数的影响并优选了工艺参数组合。结果表明:建立的有限元分析模型合理可靠;工件摆放方式与间距协同影响沉积结果。在工艺参数范围内,温度对沉积均匀性影响较大,影响程度达28.39%;其次是压力,影响程度为13.90%;反应物甲基三氯硅烷(MTS)流量影响最小,影响程度为6.43%。此外,随着温度、压力的减小和MTS流量的增大,沉积均匀性提高;根据影响规律对工艺进行优化后沉积均匀性提高了102.45%。

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%.