Tribological characterization of hard coating film for elliptical surface peak

Abstract

The hard coating film on optical devices are the major methods to control wear and friction for industrial applications. This paper used fractal characteristics of surface topography such as elliptic ratio of surface roughness, coating hardness, and surface energy to build microcontact model of rough surface, in order to research contact behaviors between elliptical surfaces. Results of analysis showed that increased elliptic ratio, soft coating and adhesive force caused increase of contact area. When fractal roughness parameter and external force decreased, the true contact area also increased. When adhesive force remained unchanged, the increase of hardness value coefficient value resulted in the increase of true contact area. True contact area also increased as the fractal dimension increased from 1.1, and reached its maximum when fractal dimension reached 1.7, but would decreased when fractal dimension continued to increase. Such critical fractal dimension was affected by external force, fractal roughness coefficient and material characteristics.