Friction and wear properties of pitch／resin densified carbon—carbon composites used for airbrakes

By use of X-ray diffractometry and scanning electron microscope (SEM), the friction and wear results obtained from MM-1000 dynamometer tests of CVI pitch/resin C/C composites were analyzed. By investigating the factors that affected the friction and wear properties, such as matrix carbon, application environment, graphitization degree and brake pressure, etc, friction and wear mechanism of carbon materials were probed. The results indicate that pitch densified CVI initially treated composite is more graphitizable with its graphitization degree up to 62%, and which results in uniform small debris easier to generate, more smooth friction curves with the coefficient of 0.3～0.4 and relatively higher linear wear and mass loss, compared with CVI/resin C/C composites. It was further proved by SEM observation that tribological behavior of C/C composite was system dependent. Factors determining the friction and wear properties such as the size of debris and its influence on friction and wear, brake pressure, graphization degree and debris film formation interacted and affected each other. The friction and wear mechanism of C/C composites under different high temperature treatments needs further research.