Tribological evaluation and lubrication mechanisms of nanoparticles enhanced lubricants in cold rolling

Base oils containing different nanoparticles with varying concentrations are prepared, in which SiO2 , TiO2 and ZnO (20 nm) nanoparticles are employed to improve the lubrication performance. Their tribological properties are evaluated on a ball-on-disk tribometer. The results show that the nano-additive lubricants exhibit a good friction reduction and anti-wear ability at the optimal concentration of 1.0 wt.%, in which SiO2 nanoparticles can reduce the coefficient of friction (COF) and the area of wear scar (AWS) by 45.6% and 35%, respectively. The SiO2 nanoparticles exhibit the best potential additive tested. The lubrication mechanisms of the nanoparticles can be attributed to the rolling, mending and the protective films.