Tribological performance of silicone oil based Al2O3 nano lubricant for an Mg alloy subjected to sliding at elevated temperatures

Lubricants are commonly used in manufacturing processes, such as rolling and drawing, to protect contact surfaces in a relative movement against friction and wear. Currently, there are few studies on fluid lubricants for the fabrication of large-scale Mg alloy components at high temperatures in the open air. This paper aims to design a type of silicone oil based Al2O3 nano lubricant and investigate its effect on the tribological performance of Mg AZ31B sliding against 86CrMoV7 steel under elevated temperatures with the aid of the pin-on-disc experiments. It was found that the width and depth of the wear tracks at 250 °C are dramatically reduced when the concentration of the Al2O3 nanoparticle additives reaches 0.50 wt% and above, and that there is a strong correlation between the wear rate and average friction coefficient. The investigation revealed that the lubrication mechanism for the contact pair using pure silicon oil at 100 °C is due to the formation of a Si-rich tribofilm, whereas the lubricant with Al2O3 nanoparticles provides a more stable Al-rich anti-wear surface at higher temperatures in the range of 200–250 °C.