Modeling of gas phase diffusion
transport during chemical vapor
infiltration process
transport during chemical vapor
infiltration process
(1. State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China;
2. Loudi Agriculture and Agro-machine School,
Loudi 417000, China;
3. State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi′an 710072, China)
Central South University, Changsha 410083, China;
2. Loudi Agriculture and Agro-machine School,
Loudi 417000, China;
3. State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi′an 710072, China)
Abstract: In order to improve the uniformity of both the concentration of gaseous reagent and the deposition of matrix within micro-pores during the chemical vapor infiltration (CVI) process, a calculation modeling of gas phase diffusion transport within micro-pores was established. Taken CH3SiCl3 as precursor for depositing SiC as example, the diffusion coefficient, decomposing reaction rate, concentration within the reactor, and concentration distributing profiling of MTS within micro-pore were accounted, respectively. The results indicate that, increasing the ratio of diffusion coefficient to decomposition rate constant of precursor MTS is propitious to decrease the densification gradient of parts, and decreasing the aspect ratio (L/D) of micro-pore is favorable to make the concentration uniform within pores.
Key words: Chemical vapor infiltration; modeling; diffusion transport; composites