TECHNIQUE FOR MONITORING DENSIFICATION DURING CHEMICAL-VAPOR INFILTRATION

A new technique for studying the progression of densification during t he fabrication of composites by chemical vapor infiltration is present ed, The preparation of a carbon-matrix composite was investigated by m omentarily interrupting, at various times, the carbon infiltration pro cess to permit deposition of very thin layers of SiC. Microscopic exam ination of these layers on a polished cross section permitted determin ation of the extent of infiltration at various locations within the pr eform as a function of infiltration time. The technique also distingui shes open from closed pores and provides information on the existence of temperature gradients within the preform.