Reciprocating sliding tribology of ceramic fiber composites with variation of laminate orientation and surface conformity

In this study, sliding behavior of carbon/carbon (C/C) and carbon/carbon-silicon carbide (C/C-SiC) composites was investigated under reciprocating sliding conditions with the variation of laminate orientation and surface conformity. The normal and parallel orientation of laminates with partial and low conformity contacts were considered. The normal load was varied from 50 N to 90 N in the steps of 10 N to investigate the effect of load. The contact pressure changed with surface conformity at the same load. Worn surfaces of composites were analyzed under scanning electron microscope to gain an understanding of the dominant wear mechanisms. The results showed that friction coefficient of composites loaded with parallel orientation of laminates was more stable as compared to normal orientation of laminates but normal orientation of laminates yielded higher value of friction coefficient. Low conformity contacts showed lower value of friction coefficient as compared to partial conformity contacts. When the normal load was increased beyond 80 N in case of parallel orientation of laminates, wear loss increased rapidly. In case of very low conformity contacts, C/C-SiC composites showed almost linear increase in wear loss with load. Friction coefficient decreased almost two times and wear loss decreased about 8 times in case of low conformity contacts as compared to partial conformity contacts. Friction film formation, disruption, adhesion and abrasion of contact conjunctions were main parameters which depicted the tribological behavior of C/C and C/C-SiC composites.