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

Effects of tuned surface wettability on oil film formation in a hydrodynamically lubricated contact under limited lubricant supply was explored in this study. Utilizing a slider-on-disc lubricating film test rig, oil film thickness was measured for three surface wettability configurations: original disc surface and original slider side surface (OD & OS), AF coated disc surface and original slider side surface (AFD & OS), and AF coated disc surface and 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 owing to the oil’s non-wetting behavior on the AFD & AFS surfaces, particularly the discontinuous oil droplet/strip by dewetting, which promote more lubricant supply at the slider inlet. Moreover, the oil accumulates at the inlet in the form of convex reservoir so that positive Laplace pressure is generated, which effectively bears part of the load and the film thickness increases.