Studies on the effects of operating parameters in manufacturing C/SiC composites by the pulse-CVI

Abstract

Manufacturing C/SiC composites from the reaction of methyltrichlorosilane (NITS) and hydrogen by the pulse CVI (Chemical Vapor Infiltration) was studied. In the pulse CVI, three steps such as evacuation of the reactor (t(e)), injection of reactant gases (t(i)), and infiltration and deposition reaction during a hold-on period (t(r)) were repeated. Effects of each step were studied by changing the duration of each step. As the evacuation time increased and the reaction time decreased during the same total actual reaction time, the amount of deposition in the preform increased. Effects of the changes of evacuation time were greater than those of reaction time. The same results were confirmed with the thermal analysis data, porosimeter, and SEM.