Dry sliding tribology of carbon fibre reinforced ceramic matrix composites with variation of laminate orientation and surface conformity

Abstract

Tribological behaviour of composites depend upon the surface conformity of interacting surfaces, local friction and wear response, and interaction area proportion of its constituents. Several other factors like wear debris interaction with the contact surfaces, and braking energy are also involved during in-service conditions. For laminated composites, interaction area proportion and wear debris interaction change with the orientation of laminates, due to change in surface conditions. Earlier research on tribological behaviour of carbon/carbon (C/C) and carbon/carbon-silicon carbide (C/C-SiC) composites mostly dealt with the parallel orientation of the laminates, and fully conformal surfaces. Thus, present article aims to investigate the tribological behaviour of C/C and C/C-SiC composites with variation of laminate orientation, surface conformity, normal load and sliding velocity. Normal and parallel orientation of laminates were considered with low and non–conformal Hertzian contacts. Worn surfaces were analysed under scanning electron microscope. The results show more fluctuations in friction coefficient (COF) for normal orientation of laminates. C/C-SiC composites loaded with parallel orientation of laminates generally exhibited highest COF and lowest wear loss. COF and wear loss decreased in non-conformal Hertzian contacts when compared with low conformity contacts and the reduction was large for C/C composites as compared to C/C-SiC composites.