Laser-induced improvement in tribological performances of surface coatings with MoS2 nanosheets and graphene

To deal with the corrosive property of bio-oil, laser-induced coatings were synthesized on the typical cylinder liner rubbing surfaces. Two nano-additives including MoS2 nanosheets and graphene were introduced into the coatings. The tribological performances of the coated surfaces were tested on a multifunctional cylinder liner-piston ring tribometer. The surfaces before and after sliding were characterized with modern surface analysis technology including Raman spectra, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and etc. The results show that the nickel-based coated surfaces can effectively prevent the corrosion of the bio-oil. In addition, the laser-induced coatings had better antifriction and antiwear performances than the corresponding traditional electroless plating coatings. With the introduction of MoS2 nanosheets or graphene, the tribological performances of the coatings were further enhanced. Laser irradiation increased the concentration of the nano-additives in the coatings and the thickness of the tribo-layers, which accounted for their outstanding tribological performances.