LAUSR

Abstract A stable aqueous graphene dispersion named polyethylenimine-reduced graphene oxide (PEI-RGO) nanosheets was prepared via an improved Hummer's method and water bath method. The sample was characterized using FTIR, Raman, UV–vis, SEM, TEM and AFM. PEI-RGO nanosheets showed an excellent dispersibility and stability in water-based fluids. The steel ball-plate tribotest results revealed that compared with pure deionized water as lubricant, a 0.05 wt% PEI-RGO in water showed a significant reduction in the friction coefficient (54.6%) and wear rate (45.0%). The decreasing of iron oxide and the appearance of PEI-RGO on the wear surfaces suggested that PEI-RGO nanosheets as one of nanoaddtives in water-based lubricant formed a film which exhibits both antiwear and anticorrosion effects on the wear surface.