Preparation of few-layer graphene by liquid-phase exfoliation and its tribological properties as deionized water additive

The few-layer graphene was prepared via the exfoliation of the expanded graphite by liquid-phase ultrasonic treatment in dimethyl sulfoxide (DMSO). The microstructure and morphology of the few-layer graphene were characterized. The tribological properties of the few-layer graphene as a deionized water additive were investigated on a model MFT-R4000 multi-functional reciprocating friction and wear tester. The morphology, elemental composition and chemical state of the worn surface were analyzed by 3D laser microscopy, scanning electron microscopy, energy dispersive spectrometry and X-ray photoelectron spectroscopy, respectively. The results indicate that the few-layer graphene prepared exhibits the excellent properties of friction and wear as an additive in deionized water. The few-layer graphene changes the wear mechanism of friction pair lubricated with deionized water, i.e., the compound wear mechanism of adhesive wear and abrasive wear becomes the main abrasive wear with slight electrochemical corrosion wear. This can be attributed to the formation of adsorption or deposition film and interlayer sliding of the few-layer graphene and the tribochemical reaction film on the worn surface. ©, 2015, Chinese Ceramic Society. All right reserved.