Tribological behaviour of surfaces with stepped wettability under limited lubricant supply

Using less lubricant is currently a trend in tribology design to address fuel economy and environment concerns. The present study was conducted to identify how an oleophilic lubrication track bounded by oleophobic areas achieves efficient lubrication under limited lubricant supply (LLS) conditions. Findings showed that the stepped wettability formed at the border of the oleophilic track can reduce the coefficient of friction and wear for steel ball-on-steel plate contact in a mixed lubrication regime, and the width of the oleophilic track plays an important role. Correspondingly, optical interferometry measurement showed that the stepped wettability can improve lubricant replenishment and increase the film thickness. The unbalanced interface from the stepped wettability enhances the replenishment of the lubricant on the contact track.