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

A numerical model was developed in order to describe the thermal-gradient c hemical vapor infiltration (CVI) for the production of SiCW/Al2O3 composite . The proposed model considered reaction, diffusion and deposition of alumi na within the porous preform. The cubic array of disconnected cylinders mod el was proposed in order to represent the porous structure of the preform a nd the composite. The experimental results of CVI were in good agreement wi th the calculated results. The effects of total pressure, healing temperatu re and initial surface temperature on the final residual porosity ansi the infiltration time were investigated. The heating temperature and the initia l surface temperature had a larger effect on the porosity: and the infiltra tion time than did the total pressure. In order to produce a dense composit e, the initial surface temperature must decrease with increasing heating te mperature. (C) 2001 Elsevier Science Ltd. All rights reserved.