Friction and wear behavior of a carbon/carbon composite material for aircraft brake disk was experimentally investigated. Friction and wear test setup was designed and built for the experiment. Friction and wear tests were conducted under various sliding conditions. Friction coefficients were measured and processed by a data acquisition system and amount of wear measured by a balance. Stainless steel disk was used as the counterface material. Temperature was also measured by inserting thermocouple 2.5 mm beneath the sliding surface of the carbon/carbon composite specimens. Wear surfaces were observed by SEM and analyze by EDAX.
The experimental results showed that sliding speed and normal force did not have significant effects on friction coefficient and wear factor of the composite. Temperature increase just below the surface was not large enough to cause any thermal degradation or oxidation which occurred at higher temperatures than when tested by TGA. When film was generated both on the specimen and the counterface at relatively low sliding speed but cracks, grooves, and films were observed at high sliding speed. Friction coefficient remained almost constant when the sliding speed or normal load was varied. It was believed that the adhesive and abrasive components contributed mainly to the friction coefficient. When wear factor was increased as the sliding speed and normal load were increased, wear behavior at low sliding speed were governed by wear film formation and adhesive wear mechanism. At high speed, fiber orientation, ploughing by counterface asperities, and fiber breakage dominated the wear of carbon/carbon composite.
