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.

Acknowledgements

The authors acknowledge the financial help provided by a faculty research grant (# R-265-000-132-112) to SKS which enabled us to purchase the entire polymer samples used in this work.