Chemical vapor infiltration of fiber-reinforced ceramic composites

A process has been developed for the fabrication of fiber-reinforced SiC composites by chemical vapor infiltration. Infiltration times for the low-density fibrous structures were reduced significantly from previous processes by simultaneously utilizing a thermal gradient and forced gas flow. Uniform matrix deposition occurred throughout unidirectional-fiber, cloth, or random chopped-fiber preforms to produce composites with densities approaching 90% of theoretical. Fabrication of composites in this fashion produced specimens with high flexural strengths and with a strain at maximum load which significantly exceeded those of conventional SiC bodies.