Short CommunicationThe bi-Gaussian theory to understand sliding wear and friction

•Evolution of bi-Gaussian surface parameters during a wear process is investigated.•The above evolution is linked to the history of the coefficient of friction.•The above link reveals the essence of the stable period during a wear process.

Surface, as the fingerprint of a component, is of interest to reveal the nature of sliding wear. Many researchers attempted to link the coefficient of friction (COF) to the surface topography from the perspective of a classical single-stratum surface, but few studies have focused on a bi-Gaussian stratified viewpoint, whereby wear mechanism can be understood. Herein, a surface-surface dry sliding experiment with silicon carbide versus carbon graphite is discretely stopped, cleaned, measured and restarted to obtain the histories of the bi-Gaussian surface parameters and the COF during the wear process. Two bi-Gaussian evolution modes are observed, from the surface-topography viewpoint, providing a reasonable explanation why the COF remains unchanged during the stable period wherein the surface topography varies with time.