Synthesis of ionic liquid functionalized graphene oxides and their tribological property under water lubrication

摘要

Ionic liquid functionalized graphene oxides (GOs-IL) were synthesized by the amidation and cation- stacking, and their tribological property as the water-based lubricant additives was investigated. The GOs-IL exhibited superior friction-reducing and antiwear performance. Specifically, under the same test conditions, the mean friction coefficient and wear volume of 0.02wt% GOs-IL/base liquid suspension were 57% and 76% lower than that of base liquid. The worn surface analyses revealed that the boundary tribofilm composed of the GOs-IL deposition film and chemical reaction film should formed on the wear scar lubricated by the GOs-IL/base liquid suspension. The proposed lubrication mechanism illustrated that the IL functional groups of GOs-IL improved their absorption and embedded stability on the rubbing surfaces by the electrostatic interactions, and then promoted the formation of the above boundary tribofilm. The tribofilm directly prevented the rubbing surfaces from the immediate contact and hence greatly reduced the friction and wear.