Low cost, high density aircraft friction materials utilizing low fiber volume nonwoven preforms with pitch densification

Abstract

Method of making a carbon-carbon composite brake disc or pad by: needling a plurality of layers of fibrous fabric segments to one another to form a brake disc or pad preform; carbonizing the fibrous preform to provide a carbon fiber brake disc or pad preform having a fiber volume fraction in the range 17% to 30% in the brake disc or pad preform; densifying the resulting carbonized needled fibrous fabric preform with pitch (isotropic or anisotropic) or with pitch and CVD/CVI; carbonizing the resulting pitch-infiltrated carbon fiber disk to carbonize the pitch therein; heat-treating the resulting pitch-densified carbon brake disc or pad; and subjecting the carbon brake disc or pad to a final cycle of CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad having a density of at least 1.70 g/cc and having a uniform through-thickness density. Benefits over conventional processing are obtained by increasing the needling rate used to manufacture the preform and reducing the amount of fiber used in the preform. In addition, the use of pitch in combination with CVI/CVD to densify the carbon fiber preform enables higher final densities to be achieved. This carbon-carbon composite manufacturing method also benefits from lowered manufacturing cycle time.