TRIBOLOGICAL PERFORMANCE OF A 3-D CARBON-CARBON COMPOSITE .1. AMBIENTENVIRONMENT

The tribological performance of a three-dimensional (3-D) carbon-carbo n composite in room temperature air was established using a reciprocat ing pin-on-flat test technique. Test load, sliding orientation with re spect to the Z fiber tow axis, and the effect of conforming-area-conta ct were studied to evaluate their effects on, coefficients of friction and wear rates. Applied load had a pronounced effect with lower coeff icients of friction and wear rates for the higher test loads. Coeffici ent of friction closely followed solid lubrication theory. Sliding ori entation influenced coefficient of friction only at the lowest test lo ads with more beneficial results for a sliding orientation parallel to the flat fiber-tow-axis. Conforming geometry resulted in higher coeff icients of friction than point contact, presumably due to larger conta ct areas and thus lower stress levels. The wear mechanism appears to b e polishing wear of the sliding pin with material transfer to the stat ionary flat, resulting in material coverage across fiber tows.