Surface electronic and morphological behaviours of copper under different wearing load conditions

Abstract

In this study, electronic and morphological behaviours, represented by the electron work function and surface roughness respectively, in copper under different wearing conditions such as load and time, were investigated using a scanning Kelvin probe, a tribometer and an atomic force microscope. The results showed that the work function initially decreased with increasing load and time and then became stable after a certain period of time, whereas the surface roughness increased and then became stable. Furthermore, the onset of wear or the history before measurable wear can be reflected based on the response of the work function. The present study demonstrates that the Kelvin probe technique could be promising for the characterisation of wear behaviour particularly at the early stages of wear because of the work function as an extremely sensitive signal.