Tribological performance of rare-earth alkylsalicylate as lubrication additive

Purpose - The purpose of the paper is to study the tribological performance of an oil soluble mixed rare-earth alkylsalicylate (REA) as lubrication additive in VG 26 white oil, and to estimate the action mechanism. Design/methodology/approach - The organo rare-earth compound is synthesized, and added in base oil with different concentrations. The tribological performances of the organo rare-earth compound as a lubrication additive in VG 26 white oil and its anti-wear properties are evaluated with a four-ball friction and wear tester. The wear scar is analyzed with X-ray photoelectron spectroscopy (XPS). Findings - The novel compound exhibits excellent anti-wear, load-carrying and friction-reducing capacities in base stock. The analytical results of XPS indicate that the excellent performance of REA can be attributed to the formation of a boundary lubricating film mainly composed of alkylsalicylic acid, rare earth oxide, and complexes of rare earth metals, which is formed on a rubbed surface when lubricated by oil containing the REA additive. Research limitations/implications - Their antioxidant and anticorrosion properties are not estimated. Practical implications - One useful AW and EP lubricating oil additive is synthesized, and maybe it is the potential industrial applied lubricating oil additive. Originality/value - This paper provides a study of organo rare-earth compounds as lubrication additives.