Enhancing tribological properties of carbon-based films through catalytic Ni3C

A composite lubrication system, which comprises a carbon-based film and lubricating oil, represents an effective strategy for enhancing traditional single-oil-based lubrication schemes. The inherent amorphous structure of the carbon-based film also holds considerable potential for the improvement of mechanical and tribological properties, as well as for the increased functionalization of carbon-based films through doping or the creation of specialized microstructures. In this study, the catalytic activation of the amorphous carbon-based film was achieved by introducing Ni3C nanocrystal structures, further enhancing the tribological properties of the carbon-based film within the composite lubrication system. The a-C:Ni3C film exhibited a remarkably low friction coefficient of 0.05 in an oil environment, accompanied by an exceptionally low wear rate of only 4.2 × 10−8 mm3/Nm. Post-friction characterizations, in conjunction with ab initio molecular dynamics (AIMD) simulations, revealed that under the combined action of local flash heating and shear stress, the catalytic Ni3C promotes the formation of a carbon-based tribofilm at the friction interface, thereby reducing friction. Furthermore, this distinctive structural configuration enhances the film's wear resistance through robust bonding at the interfaces between Ni3C nanocrystals and amorphous phases, as well as the blocked dislocation movement within the grains caused by the amorphous-phase-induced discontinuous grain incoherent strain. [Display omitted]