Effect Of Surface Wettability On The Friction In Rough Contact Interface

The microstructure on the surface has a significant effect on the friction and lubrication performance. In the process of machining, surface topography and the lubrication and friction between workpiece and tool form a time-dependent tribological system in sliding contact interface. The complicated relationship between the above three has aroused extensive attention at home and abroad. A new design method of surface random texture was proposed based on 2D lattice model of percolation theory in order to investigate the correlation of surface topography on the tribological behavior and lubrication in sliding contact interface.Surface random micro-texture of different area ratio was manufactured by Laser marker YLP-F10 on aluminium alloy 6016 sheets. All the textured surfaces were measured by shape measurement of laser microscopy system and characterized by ISO 25178-2:2012. The wettability on the textured surface was measured by SL200KS contact angle meter. Later the sliding friction experiment in the home-made friction test device explores the influence of surface topography on friction characteristics under the condition of different contact pressure. The results show that random micro-texture surface can significantly reduce friction coefficient and the friction coefficient decreases with the increase of contact pressure. Both surface wettability and area ratio of random micro-texture exhibits a good linear relationship and surface microstructure shows critical characteristic so as to explain the mechanism of surface topography affecting friction characteristics.3D surface topography parameters including 3D average surface roughness Sa, core height Sk, void volume in valley zone Vvv, and void volume in centre zone Vvc are changed by contact pressure and friction coefficient reflecting the mechanism of surface morphology variations at a certain extent.