Abstract: This invention describes the infiltration methods used to incorporate ceramic additives in carbon/carbon brake disc preforms. Aqueous vacuum infiltration techniques were employed. Both methods were effective in achieving homogeneous dispersion of ceramic additives throughout brake disc thickness. Heat treatment processes were developed to convert oxide additives to more refractory phases. Both temperature and N.sub.2 overpressure were precisely controlled during conversion. By using the additives, infiltration routes, and heat treatment schedules, brake disc friction material performance properties such as friction coefficient, friction coefficient stability, and brake disc wear rate are improved. The disclosed carbon/carbon brake discs can be used in aerospace, automotive and other friction material applications.