Tribological properties of alcohols as lubricating additives for aluminum-on-steel contact

The tribological properties of a series of alcohols as lubricating additives in liquid paraffin were investigated using a Timken tester with a SAE52100 steel ring sliding against an A1 2024 block. The boundary film formed on the aluminum block was studied with X-ray photoelectron spectrometry (XPS) and scanning electron microscopy (SEM). It was found that these compounds possess high load-carrying capacities, good friction reduction and antiwear properties. In particular, the load-carrying capacity and antiwear ability increased with the increase of hydroxy group number in the alcohols. XPS analysis suggests that the lubricating mechanism of the alcohols compounds as additives is the formation of complex of aluminum and alcohols. SEM analysis reveals that adhesion, scoring and plastic deformation are the dominative wear.