Wear debris generation mechanism for polymers studied by nanoscratching

Abstract

This paper investigates the debris generation mechanism for polymers due to the actions of the micro-asperities of a hard counterface. Nanoscratching tests were conducted on the surface of five commercially available polymers using a diamond conical tip indenter with three different scratching sequences namely unidirectional multipass, orthogonal multipass and orthogonal omnipass. The scratch damage surface was analysed using an atomic force microscope and a scanning electron microscope to investigate the material removal phenomenon for the selected polymers. The results show that debris generation in polymers is largely a phenomenon of low-cycle fatigue when asperities contribute to the localized plastic deformation of the surface. Hence the rate of material removal is reduced for a polymer which has higher toughness and a higher percentage of elongation before failure. The hardness of the polymer has a counter effect on wear as higher hardness tends to reduce the toughness property in polymers which leads to microcracking and further wear debris generation.