New Graphene/Ionic Liquid Nanolubricants

In this work, we have prepared new graphene/ionic liquid dispersions by adding a 0.1 wt.% proportion of 1-2 layers graphene (G1) or 1-10 layers graphene (G2) to the ionic liquid 1-octyl-3-methylimidazolium tetrafluoroborate (IL). The new dispersions (IL +G1) and (IL +G2) have been used as external lubricants in polymer-steel and ceramic-steel contacts. For AISI 316L stainless steel/epoxy resin, the order of friction reduction is (IL +G2)>IL>(IL +G1). The wear reducing order is the same, as abrasive wear takes place for (IL +G1), while G2 prevents any degree of surface damage on both materials, even the very mild wear observed for neat IL. The poor performance of G1 is related to the formation of abrasive graphene-IL aggregates. The (IL +G2) dispersion also shows superior friction reducing and anti-wear behavior under more severe contact conditions, for AISI316L against sapphire.