Experimental evaluations on tribological performance of oil-based WS2 nanofluid applied on steel/brass friction pairs

Abstract

The present research evaluated the tribological performance of oil-based WS2 nanofluids applied on steel-brass friction pairs. It was found that the coefficient of friction could be reduced by up to 39%, and the wear width and depth could be reduced by up to 28.7% and 66.4% using 1\xa0wt% WS2 nanofluid. While using the WS2 nanofluids, almost no adhesive wear was detected on the worn surfaces. By analyzing the chemical compositions, carbon percentage increased after engaging the oleic acid which suggested tribo-films with low shear resistance were formed. In addition, elements of sulfur and tungsten were found within the wear track lubricated by WS2 nanofluids. It was believed that the WS2 nanoparticles were involved in the formation of the tribo-layers and mixed with the oleic acid tribo-films to improve the tribological behavior. Moreover, the tribo-layers produced by the WS2 nanoparticles could provide solid lubricating and mending effects on the mating surfaces.