Friction and Wear of MoS₂ Films on Laser Textured Steel Surfaces

Incorporation of solid lubricant into micro-reservoirs produced by Laser Surface Texturing (LST) and its effect on the tribological properties of surfaces under dry friction is studied. The density of the dimple reservoirs and the height of the bulges around them are investigated in terms of the longevity of solid lubricant films burnished on LST steel surfaces. Friction tests were performed using a ball-on-flat device. Optimum density (40–50%) of the dimples is revealed. It is shown that the adhesion of solid lubricant in the space between the dimples is provided by mechanical engagement of particles in the rough surface and by smearing the solid lubricant around the dimples. Best results are obtained with the surfaces that were lapped to half of the height of bulges. Long wear life of burnished film on LST steel surfaces is apparently provided by preservation of thin MoS₂ film around the bulges and by supply of solid lubricant from the dimples to the surface. The effect of repeated burnishing on wear life of solid lubricant films was studied. Repeating burnishing leading to increasing the density of solid lubricant films increases the wear life.