Halogen-free ammonium–organoborate ionic liquids as lubricating additives: the effect of alkyl chain lengths on the tribological performance

Abstract

Novel halogen and phosphorus free ionic liquids containing chelated organoborate anions having different alkyl chain lengths and tetrabutyl ammonium cations have been studied as anti-wear and friction reducing agents under elasto-hydrodynamic/mixed lubrication conditions for steel–steel contacts. The synthesized ionic liquids were found to be quite stable at room temperature and showed a remarkable improvement in the friction-reducing and anti-wear properties of the PEG 200 lube base. The effect of alkyl chain lengths on the tribo-performance of the synthesized additives was systematically studied.