Phosphonium-based ionic liquids as additives in calcium/lithium greases

This work studies the performance of three phosphonium-based ionic liquids ([P6,6,6,14][BEHP], [P6,6,6,14][TCM] and [P6,6,6,14][DEC]) when used separately as additives on thermal conductivity, stability tribological properties two non-additised greases (a lithium-based a calcium-based grease). The main results confirmed that improved both greases. Only mixtures G1 + 5%[P6,6,6,14][BEHP] G2 5%[P6,6,6,14][TCM] showed slight increase in conductivity. In general, addition ILs to grease increased friction coefficient four-ball tests reciprocating tests, while decreased with tests. [P6,6,6,14][BEHP] antiwear behavior under whereas all worsened had best due higher interaction phosphorous metal surface. A possible interference calcium thickener liquid–metal surface was found, resulting lower grease.