Patent ID: 8268207

Claim:
A method of manufacturing a pitch-based carbon-carbon composite useful as a brake disc, the method comprising the following sequential steps: (a) heat-treating an annular carbon fiber preform comprising a nonwoven fabric at 1200° C.-2540° C.; (b) densifying the preform by infiltrating the carbon fiber preform with a pitch feedstock by vacuum pressure infiltration (VPI) or resin transfer molding (RTM) processing; (c) carbonizing the pitch-infiltrated carbon fiber preform at 1200° C.-2200° C. in an inert atmosphere; (d) repeating steps (b) and (c) to achieve a density in the carbon fiber preform of approximately 1.5 grams per cubic centimeter (g/cc) to below 1.7 g/cc; and (e) densifying the preform by a single cycle of chemical vapor deposition (CVD) or chemical vapor infiltration (CVI) to provide a C-C composite which: (i.) has a rough laminar microstructure and is densified at a temperature of 1275° C., a pressure of 210 Torr, and a C/H ratio of 1/4; (ii.) has a smooth laminar microstructure and is densified at a temperature of 1200° C., a pressure of 630 Ton, and a C/H ratio of 1/4; or (iii.) has an isotropic microstructure and is densified at a temperature of 1425° C., a pressure of 630 Ton, and a C/H ratio of 1/4, wherein said C-C composite has a density higher than 1.7 g/cc.