Jy. Ofori et Sv. Sotirchos, OPTIMAL PRESSURES AND TEMPERATURES FOR ISOBARIC, ISOTHERMAL CHEMICAL-VAPOR INFILTRATION, AIChE journal, 42(10), 1996, pp. 2828-2840
This study addresses the possibility of identifying optimal pressure a
nd temperature pairs that can be used to give the leat processing time
during isobaric isothermal chemical-vapor infiltration (CVI) within a
window of operating conditions. Optimal pressure-temperature pairs ar
e determined as the solution of an optimization problem that seeks to
minimize the processing time predicted by a CVI model under the constr
aint that the maximum density difference in the preform at the end of
the densification does not exceed a preset limit. Results are presente
d on the dependence of the optimum processing time on the type of stru
cture of the preform, the specifications that the final product has to
conform to, and the kinetics of the chemical reaction. The results sh
ow that operation at low pressure affects adversely the processing tim
e and that a dramatic reduction in the processing time can be achieved
by operating in the vicinity of the optimal pressure.