Patent ID: 7897072
Filing Date: 2011-03-01
Classification: C04B,F16D

Abstract:
1. A method of manufacturing a low cost carbon-carbon composite friction material using isotropic coal tar pitches, which method comprises the sequential steps: (a) providing a chopped fiber or nonwoven fabric-based carbon fiber preform in the form of an annular aircraft brake disc; (b) heat treating the annular fabric-based carbon fiber brake disc preform at 1200-2540° C.; (c-1) infiltrating said preform with an isotropic coal tar pitch by employing vacuum pressure infiltration (VPI) or resin transfer molding (RTM) processing; (d-1) carbonizing the resulting isotropic coal tar pitch-infiltrated carbon fiber preform at 1200-2540° C.; (c-2) infiltrating said preform with an isotropic coal tar pitch by employing vacuum pressure infiltration (VPI) or resin transfer molding (RTM) processing; (d-2) carbonizing the resulting isotropic coal tar pitch-infiltrated carbon fiber preform at 1200-2540° C.; (c-3) infiltrating said preform with an isotropic coal tar pitch by employing vacuum pressure infiltration (VPI) or resin transfer molding (RTM) processing; (d-3) carbonizing the resulting isotropic coal tar pitch-infiltrated carbon fiber preform at 1200-2540° C., whereby the density of the preform is at least 1.75 g/cc; and (f) heat-treating the resulting isotropic coal tar pitch-densified carbon fiber preform at 1200-2540° C. to produce said carbon-carbon composite friction material, wherein no CVI/CVD processing is utilized in the production of said carbon-carbon composite friction material.