Patent ID: 7700014

Claim:
A method to rapidly densify a fibrous jet aircraft brake disc preform in order to manufacture a carbon-carbon composite material of medium to high density at low cost, said method comprising the steps of: (i.) providing at least one fibrous brake disc preform, made of carbon fiber or carbon fiber precursors, selected from the group consisting of nonwoven preforms, needled fiber preforms, and random fiber preforms; (ii.) infiltrating said preform with isotropic coal tar pitch to form a pitch-infiltrated preform under a vacuum of below 50 torr via a single cycle of Vacuum Pitch Infiltration (VPI) processing; (iii.) carbonizing said pitch-infiltrated preform for a period of from 18 hours to 3 days, and optionally removing excess carbonized pitch from and/or optionally heat-treating said pitch-infiltrated preform after this carbonization step; (iv.) placing the resulting porous preform into a mold, generating a temperature above a melting point of a AR mesophase pitch to be transferred into the preform, and constraining the mold so that the mold retains its configuration; (v.) injecting high viscosity AR mesophase pitch into the mold and driving said high viscosity pitch through the thickness of the jet aircraft brake disc preform via a single cycle of Resin Transfer Molding (RTM) processing to effect a uniform impregnation of the preform via a pressure gradient in the mold and to provide the preform with a density of 1.55 g/cc or higher; (vi.) allowing the AR mesophase pitch in the preform to cool below its melting point; (vii.) subjecting the densified preform to oxygen stabilization to inhibit melting of the AR mesophase pitch during carbonization; (viii.) carbonizing and heat-treating the oxygen-stabilized impregnated preform prepared in step (vii.); and (ix.) subjecting the preform produced in step (viii.) to a single final cycle of chemical vapor deposition (CVD) to provide a carbon-carbon composite preform having a density of 1.7 g/cc or higher, wherein step (ix.) is the sole CVD cycle employed in the course of manufacturing said jet aircraft brake disc preform.