Axle gear oils: Friction behaviour under mixed and boundary lubrication regimes

Abstract The chemical composition of the axle lubricants and the tribological characteristics of the tribofilms are probed using measurement of friction, wear and film characteristics. Additives blended in the lubricants justified the frictional behaviour under mixed lubrication regime while surface texture and the tribofilm properties have substantiated the friction behaviour of the lubricant under boundary lubrication condition for high-lubricant temperature. This work will provide a comprehensive overview of two lubrication aspects and their effects on the lubricants friction behaviour through experimental tests using an EHD2 ball-on-disc apparatus. The effectiveness in friction reduction is shown depend on the ratio between what are defined as high- and low-friction species in the tribofilm.