Preparation and tribological properties of the N‐containing heterocyclic borate esters and Cu microparticles as lubricant additives in base oil

Abstract

AbstractIn this paper, four kinds of N‐containing heterocyclic borate esters and polyvinyl pyrrolidone‐protected Cu microparticles were synthesised and characterised. Their tribological properties as lubricant additives in industrial white oil were evaluated using a four‐ball tribometer, and their lubrication mechanisms were investigated by X‐ray photoelectron spectroscopy. The results showed that the anti‐friction and anti‐wear performance of the base oil can be significantly improved by the addition of N‐containing borate esters and Cu microparticles, and they present synergistic tribological effect. Moreover, X‐ray photoelectron spectroscopy results showed a lubricating tribochemical reaction film containing B2O3, FeB, FeO, Fe2O3 and so on is formed on the worn surface. In addition, Cu microparticles as rolling bearings, which transform sliding friction to rolling sliding and the formation of the Cu microparticles deposited film, are probably responsible for the improvement of tribological performance. Copyright © 2017 John Wiley & Sons, Ltd.