Numerical simulation of the thermal-gradient chemical vapor infiltration process for production of fiber-reinforced ceramic composite

摘要

a numerical model was developed in order to describe the thermal-gradient chemical vapor infiltration (CVI) for the production of SiC_W/Al_2O_3 composite. The proposed model considered reaction, diffusion and deposition of alumina within the porous preform. The cubic array of disconnected cylinders model was proposed in order to represent the porous structure of the preform and the composite. The experimental results of CVI were in good agreement with teh calculated results. The effects of total pressure, heating temperature and initial surface temperature on the final residual porosity and the infiltration time were investigated. The heating temperature and the initial surface temperature had a larger effect on the porosity and the infiltration time than did the total pressure. In order to produce a dense composite, the inital surface temperature must decrease with increasing heating temperature.