Friction characterisation of polymers abrasion (UHWMPE) during scratch tests: single and multi-asperity contact

An understanding of abrasion resistance and the associated surfaces deformation mechanisms is of primary importance in materials engineering and design [Wear (1998)]. Instrumented scratch testing has proven to be a useful tool for the characterisation of the abrasion resistance of material. Although most studies on scratch resistance have been conducted for metals, assuming a purely plastic behaviour, recent studies focus on the effects of elastic and visco–elastic–plastic behaviour on the scratch mechanisms [Tribol. Int. (1998)]. In this study, normal and tangential scratch forces are measured during the scratch experiments using various indenter geometry and abrasive paper, under various temperature conditions (263–293 K). To complete the characterisation of the scratch process, three-dimensional topography of the scratched surface is measured. The comparison between single point scratch and multi-asperity abrasion testing is made possible thanks to morphological analysis of the abrasive paper topography. The single point scratch tests provide a good understanding of the effect of the contact geometry and temperature on the friction coefficient. These results are then used to explain the evolution of the friction coefficient obtained with two abrasive papers under various temperature and load conditions.