Use of ethyl-dimethyl-2-methoxyethylammonium tris(pentafluoroethyl)trifluorophosphate as base oil additive in the lubrication of TiN PVD coating

This paper discusses and compares the use of ethyl-dimethyl-2-methoxyethylammonium tris(pentafluoroethyl)trifluorophosphate ionic liquid [(NEMM)MOE][FAP] and the traditional zinc dialkyldithio-phosphate (ZDDP) as 1 wt% additives to a polyalphaolefin (PAO 6) in the lubrication of TIN PVD coating. Tribological tests performed using a ball-on-plate reciprocating tribometer showed how both additives improve the anti-friction and anti-wear behaviors of the base oil for the two loads tested. However, the traditional additive ZDDP showed the lowest friction coefficient in all cases. Interferometry and XPS analyses showed that the formation of tribofilms resulting from the interaction of the ionic liquid with the surface contributed to the tribological improvement. (C) 2011 Elsevier Ltd. All rights reserved.