Lubrication of an electroplated nickel matrix silicon carbide coated eutectic aluminium—silicon alloy automotive cylinder bore with an ionic liquid as a lubricant additive

Abstract

For a chromium-nitrided steel piston ring section sliding against an electroplated nickel matrix silicon carbide coated eutectic aluminium—silicon alloy automotive cylinder bore in a reciprocating tribometer, the ionic liquid (IL) imidazolium tetrafluoroborate has an excellent tribological performance as a lubricant additive in the presence of tritolyl phosphate (TTP). A low friction coefficient of 0.015 and a substantial tribofilm was generated. The performance of this base oil/additive combination was superior to the base oil alone or the separate additives in the base oil. The substantial improvement in tribological performance given by addition of an IL and TTP, 1 per cent by volume of each, to a group III base oil indicates a synergistic interaction between the IL and TTP. The need to understand the chemical and physical nature of the tribofilm is emphasized.