Process for producing carbon/carbon composite having oxidation resistance

A process for producing a carbon/carbon composite having oxidation resistance which comprises treating the surface of a carbon/carbon composite by filling the voids of a carbon/carbon composite comprising 10-70% by volume of carbon fibers and 5-90% by volume of a carbonaceous matrix having a void percentage of 10-55% with carbon and/or a ceramic selected from the group consisting of SiC, ZrC, TiC, HfC, B.sub.4 C, NbC, WC, TiB.sub.2, BN and Si.sub.3 N.sub.4 by chemical vapor infiltration (CVI), said CVI performed at a temperature of from 1000.degree. to 1500.degree. C. and a pressure from 0.1 to 50 Torr, and then coating the treated surface with a ceramic or both a ceramic and carbon, said ceramic selected from the group consisting of SiC, ZrC, TiC, HfC, B.sub.4 C, NbC, WC, TiB.sub.2, BN and Si.sub.3 N.sub.4 by chemical vapor deposition (CVD), said CVD performed at a temperature of from 1000.degree. to 2000.degree. C. and a pressure of from 50 to 760 Torr, wherein at least one of temperature, pressure, feed gas rate and feed gas ratio employed in each of said CVI and CVD procedures is changed continuously to provide a continuous change of at least one of texture, structure and composition of said carbon and/or ceramic which effectively increases the carbon's and/or the ceramic's resistance to cracking and delamination.