Abstract
Graphene oxide (GO) has a graphite monolayer sheet structure with a thickness of below Inm and a size of over 10μm. Since GO has a 10t of oxygen functional groups, GO is easy to disperse in water. In this study, tribological properties of GO monolayer sheets as additives in water-based lubricants were investigated for tungsten carbide (WC) and SUJ2 balls with diameters of 2 mm, against SUS304 substrates, with a load of 11.IN. The density of the GO dispersion was 1 wt.%. During initial friction, a friction coefficient of the GO dispersion for the wc ball was over 0.1, and rapidly decreased to 0.05. And then the friction coefficient gradually increased and reached to above 0.11. A friction coefficient for the SUJ2 ball was relative stable with the value of 0.08-0.10. Since GO would insert between the sliding surface, GO would prevent the balls and substrates from contacting each other directly. This would suggest that GO sheets may behave as protective coatings.
