Enhanced superlubricity of 1,3-diketone oil by doping polydopamine functionalized silica nano-additive

1,3-Diketone is a promising oil-based superlubricity material on steel surfaces. However, the achievement of its superlubricity is limited within a particular range of load and velocity. In this study, silica nanoparticles were modified by surface-coated polydopamine and stably dispersed in 1,3-diketone oil as the additive. It suggests that functionalized silica nanoparticles deposited on the steel substrate and repaired the surface pits, which enhanced the superlubricity of EPND with shorter running-in time and smaller wear. Such assistance became more significant for the operation at a higher load or a lower velocity. With the controlled size of wear debris, the superlubricity region of 1,3-diketone could break through its original load (e.g., 16–43 N) and velocity (200–100 mm/s) boundaries.