Effect of filler content on scratch behavior and tribological performance of polyester/graphene oxide nanocomposite coating

The influence of 0.5, 0.75, and 1 wt.% of graphene oxide (GrO) in nanocomposite coating on scratch behavior and tribological performance was analyzed. Graphite was oxidized using the Marcano and Tour method to obtain graphite oxide, which is thermally exfoliated at 700 degrees C getting graphene oxide. The transformation of graphite to graphene oxide was evaluated via Raman spectroscopy and X-ray diffraction. Effects of graphene oxide content on the friction and wear behavior of polyester composite coatings were evaluated under dry sliding conditions. Experimental findings showed that the addition of 0.5 wt.% GrO was effective in reducing the friction coefficient of polyester coating. Meanwhile, under the same sliding conditions, the wear results revealed that the polyester coating filled with 1 wt.% GrO has better antiwear ability compared to those filled with 0.5 and 0.75 wt.% GrO. From the scratch analyses, we deduced that coating scratch behavior was highly affected by the amount of fillers inside the polyester matrix. In fact, the best friction characteristic and scratch resistance were observed in the case of polyester coatings filled with the lower amount of GrO, namely 0.5 wt.%.