Halogen-free ionic liquids as synthetic ester oil antiwear additives

Abstract

PurposeThis paper aims to investigate the tribological properties of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ionic liquids (ILs) when used as lubricant additives in synthetic ester oil.Design/methodology/approachThe 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs containing different cation-imidazolium and organo-ammonium were synthesized and characterized. Their tribological performances as lubricant additives were assessed on ball-on-flat tribological tester. Their compatibility with typical additives (such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent) were evaluated on a four-ball friction and wear tester.FindingsIt was found that the synthesized ILs demonstrated more effective friction reduction and antiwear properties than the base synthetic ester oil. The ILs worked well with the other typical additives, such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent.Originality/valueThe results of the experimental studies demonstrated the potential of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs as additives for improving friction reduction and antiwear abilities of synthetic ester oil.