Morphologies of the wear debris of polyetheretherketone produced under dry sliding conditions: Correlation with wear mechanisms

Wear debris contains extensive information on the tribological behaviours of materials [M.Q. Zhang, Z.P. Lu, K. Friedrich, On the wear debris of polyetheretherketone: fractal dimensions in relation to wear mechanisms, Tribol. Int. 30 (1997) 87–102]. Investigations on wear debris morphology will be helpful for understanding materials’ friction and wear processes. In this work, the wear debris obtained from block-on-ring (BOR) tests of three polyetheretherketones (PEEKs) with different molecular weights was studied. The mechanical properties of the three PEEKs were characterized in a previous work [G. Zhang, A.K. Schlarb, Correlation of the tribological behaviors with the mechanical properties of poly-ether-ether-ketones (PEEKs) with different molecular weights and their fiber filled composites, Wear, 2008, in press]. In this work, the influences of the mechanical properties of PEEKs and apparent pressure on wear debris morphology were studied. Based on analyzing wear debris morphologies, possibly involved tribological mechanisms were discussed. The results indicate that the tribological mechanisms have a close relationship with the morphology of the wear debris. Under low pressures, particle-like wear debris suggests that the micro-cutting effect exerted by the protruding regions of the counterpart dominates the tribological behaviour. Under high pressures, rod-like, bamboo-raft-like and film-like debris were noticed. This fact suggests that the transferring of PEEK to the counterpart and the plastic flow occurring in the PEEK surface layer play important roles on material loss.