Improving Tribological Properties of 45-Steel by Combining Laser Surface Texturing and DLC Coating

In efforts to improve the tribological properties of the 45-steel, laser surface texturing (LST) and diamond-like carbon (DLC) coating were performed on the surfaces of the steel. Three types of samples, i.e., LST followed by DLC coating (LST-C), DLC coating followed by LST (C-LST) and DLC coating without LST(C-only) were prepared. The tribological properties of the samples were investigated under dry friction and starved lubrication, respectively. The results show that compared to coating-only sample, the duplex-treatment can significantly reduce the friction coefficient and wear rate, among which LST-C samples demonstrate the best tribological performance both under dry friction and starved lubrication. DLC coating can prolong the existence time of the surface textures. Meanwhile, the dimple-textures can capture the wear debris and store lubricating oil, which help to reduce the abrasive wear and extend the existence time of stable state.