Synergistic effects between sulfurized W-DLC coating and MoDTC lubricating additive for improvement of tribological performance

Low temperature ion sulfuration technology was used to obtain sulfurized layer on W doped diamond-like carbon (W-DLC) coating. The tribological behaviors of the pure W-DLC and sulfurized W-DLC coatings were investigated under PAO and MoDTC lubrication conditions. It shows that sulfurized W-DLC coatings can obviously improve their tribological performances under PAO with MoDTC lubrication. The primary reason is due to the formation of WSx on the surface of sulfurized W-DLC coating, the decomposition of additives for formation a higher ratio of Mo sulfide/Mo oxide and the graphitization for a high ratio of sp2/sp3.