Lubricating ability of a protic ionic liquid as an additive to an ultra-low viscosity synthetic oil under electrified sliding conditions Academic Article in Scopus uri icon

abstract

  • Electric vehicles (EVs) have lately seen rapid market growth, aligning well with the green transportation needs of global society. As opposed to the well-established and -addressed tribological issues in traditional internal combustion engine vehicles (ICEV), the tribological challenges in EVs, especially under electrified contact conditions in general and those involving the use of ionic liquid (ILs) remained largely unexplored. In this study, we explored the friction and wear behavior of an ultra-low viscosity polyalphaolefin oil (PAO 2) under electrified sliding conditions with and without the use of a PIL (i.e., 2-hydroxyethylammonium 2-ethylhexanoate) as an anti-friction and wear additive. The addition of PIL to PAO 2 significantly reduced the wear losses of steel samples (i.e., as much as 84 % especially under electrified conditions), most likely due to the PIL's ability to form a protective boundary layer and its high thermal and electrical conductivity. Post-test analyses severe oxidation when pure PAO 2 was used under lower electrified conditions. In contrast, under the same conditions, the presence of PIL in the PAO oil, resulted in the formation of highly protective tribofilms composed of carbonaceous products which, significantly enhanced wear performance. Under higher electrified sliding conditions, the rate of oxide formation and removal stabilized for both pure PAO and PAO + PIL, leading to the formation of a thin oxide layer that restored mild oxidative wear and reduced wear loss. © 2025 Elsevier B.V.

publication date

  • January 1, 2025

published in