Application of Taguchi techniques to study friction and wear properties of MoS2 coatings deposited on laser textured surface

Laser surface texturing (LST) has been recognized as a viable, fast and accurate technology for surface engineering that is used to produce significant improvements in tribological performance of sliding surfaces, including their load carrying capacity, wear resistance, lubrication lifetime and reduced friction coefficients. In this study, we present the results of the combination effect of solid lubricant and LST steel surfaces on the tribobological properties. To improve the surface texturing effect on friction and wear, different multi-dimple patterns with some specific formula arrays were fabricated by laser ablation process by combining circles and triangles, and circles and squares on the surface of steel. The friction and wear test were performed using a pin-on-disc unidirectional tribometer under dry and coated MoS2, and the results compared with that of untextured surface. The influence of normal load, sliding speed and texture area density on the friction performance of multi-dimple patterns was also investigated by the Taguchi method. The results showed that the texture surface with the high dimple density had low friction at low and high applied load under dry friction. When combining the solid lubricant with dimples, the textured specimens improved the tribological performance for most applied loads. A variance analysis of the experimental data indicates that the texture area density had the highest contribution on friction coefficient and wear life followed by load and sliding speed. In general, multi-dimple textured surface had excellent tribological properties than the untextured surface under dry friction and coated MoS2 film demonstrated the potential of multi-dimple textured surface as a viable engineering surface for friction reduction and extend wear life.