Abstract
A model for the forced-flow/temperature-gradient chemical vapor infiltration (FCVI) process has been proposed in a previous study. The results demonstrate that the arrangement of the heating elements is important in the matrix deposition within a fibrous preform. In the present analysis, two cases (first-order and zero-order reaction mechanisms) of the CVI process are examined to evaluate the assumption of matrix deposition mechanisms. In the first case, the distribution of the deposited matrix depends on the competition between the temperature gradient within the preform and the rate of reactants consumed during infiltration. In the second case, the distribution of matrix deposition depends solely on the temperature gradient. The analysis concludes that the prediction of matrix deposition is influenced significantly by the selection of deposition kinetics in the model. A zero-order reaction mechanism is appropriate only if the consumption of reactant vapor is insignificant. Furthermore, it is suggested that the use of the reaction mechanism and activation energy in the FCVI model should be based on the experimental deposition results from an FCVI system.