Electrical conductivity and tribological behavior of an automatic transmission fluid additised with a phosphonium-based ionic liquid

Authors: Tuero, A.G., Sanjurjo, C., Rivera, N., Viesca, J.L., González, R. and Battez, A.H.

Journal: Journal of Molecular Liquids

Volume: 367

ISSN: 0167-7322

DOI: 10.1016/j.molliq.2022.120581

Abstract:

There are electric vehicle configurations with the electric motor (EM) inside the transmission housing, putting in contact the automatic transmission fluid (ATF) with the EM. In this case the ATF must fulfil several requirements, such as electrical and material compatibilities, improved cooling performance, etc. The use of ionic liquids (IL) as lubricant additive can impact on electrical conductivity (κ) and tribological behaviour of the ATF. This work analyses the influence of a phosphonium-based ionic liquid ([P6,6,6,14][BEHP]) used as additive at 1 and 3 wt% concentration on the abovementioned properties of a commercial ATF. The addition of the IL increased the κ of the ATF but it continues being dissipative; however, the dielectric strength decreased drastically and further tests about this property should be performed. The IL promotes the formation of a phosphorous-rich tribofilm, which is related to the improved antiwear performance. This formulation including the IL could be used in electric vehicles.

Source: Scopus