Tribological Properties of Two Bis(trifluoromethylsulfonyl)imide-Based Ionic Liquids on Steel-Steel Contact

摘要

The ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, [C_4C_1Pyrr][Tf_2N], and 1-butyl- 2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [C_4C_1C_1Im][Tf_2N], were evaluated as neat lubricants for steel-steel sliding contacts using a ball-on-plate reciprocating tribometer under loads of 8, 18, and 30 N at room temperature conditions. A formulated semisynthetic oil was used for comparison. The best tribological behavior (friction coefficient and wear volume) was obtained with [C_4C_1C_1Im][Tf_2N] regardless of the load applied. Scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis showed the presence of tribolayers containing fluorides on the lubricated metal surface produced by weak tribochemical reactions.