Surface wettability-driven oil film formation in slider-on-disc contact under limited lubrication

Abstract

The effects of tuned surface wettability on oil film formation in a hydrodynamically lubricated contact with a limited lubricant supply (LLS) were explored in this study. Using a slider-on-disc lubricating film test rig, the oil film thickness was measured for three surface wettability configurations: the original disc surface and original slider side surface (OD & OS), the anti-fingerprint (AF)-coated disc surface and original slider side surface (AFD & OS), and the AF-coated disc surface and the AF-coated slider side surface (AFD & AFS). The results indicate that the AFD & AFS combination maintains the largest oil film thickness. This enhanced performance is due to the oil’s nonwetting behavior on the AFD & AFS surfaces, particularly the discontinuous oil droplet/strip by dewetting, which promotes more lubricant supply at the slider inlet. Moreover, the oil accumulates at the inlet in the form of a convex reservoir so that positive Laplace pressure is generated, which effectively bears part of the load, and the film thickness increases.