Study on tribological properties of zinc perrhenate in oil‐based hybrid lubrication system over a broad temperature range

Abstract

The zinc perrhenate used as oil additive was synthesised via aqua‐solution method and was dispersed into pentaerythritol ester with the surface‐active agents. The tribological properties of lubricants were examined by 4‐ball tester and ball‐on‐disc testing machine. Additional investigations were performed using XRD, XPS, SEM‐EDS, and DTA/TG to probe the possible lubricating mechanism. Four‐ball test results showed compared to base oil, the friction coefficient and wear scar diameter of oil with zinc perrhenate additive were reduced by 14.9% and 16.6%, suggesting that zinc perrhenate additive could improve the lubricating property of base oil under 4‐ball test condition. Frictional tests under a wide temperature range indicated that oil with zinc perrhenate additive exhibited friction‐reducing performance during elevated temperature process because of its intrinsic shear susceptible property and could form a protective layer with native oxides of the disc sample at the interface, thus significantly minimised friction.