Simulated-stop tribological behavior of pitch—resin—CVI carbon—carbon composite

Abstract

This work studies the braking (simulated-stop) behavior of a mesophase pitch fiber-reinforced phenolic resin plus chemical vapor infiltrated (CVI) hybrid matrix carbon—carbon (C-C) composite under different surface conditions. The results indicate that friction and wear behavior is sensitive to sliding surface condition, and the initial surface condition has a significant effect on tribological behavior of the composite. AP/1400, the only condition that does not experience a transition, shows much lower friction coefficient and wear than the other conditions. Under the same test conditions, BI specimens exhibit higher friction coefficients and wear than those of AP specimens. Of all the conditions, BI/2000 induces the highest temperature rise. Specimens braked from higher speed always suffer higher wear, but the stopping time is dependent more on the initial surface condition than the initial speed. As soon as a type I-to-type II transition occurs, the friction and wear rise abruptly. A V-shaped variation is exhibited in post-transitional friction coefficient of the composite. The severe structural damage during the final stage is responsible for the final increase in friction coefficient. Collection of large wear particles is consistent with the observed heavily delaminated surface film during this stage.