Preparation and Tribological Properties of WS₂ Hexagonal Nanoplates and Nanoflowers

This paper presents the facile synthesis of two different morphologies of WS₂ nanomaterials-WS₂ hexagonal nanoplates and nanoflowers-by a sulfurization reaction. The phases and morphology of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The tribological performance of the two kinds of WS₂ nanomaterials as additives in paraffin oil were measured using a UMT (Universal Mechanical Tester)-2 tribotester. The results demonstrated that the friction and wear performance of paraffin oil can be greatly improved with the addition of WS₂ nanomaterials, and that the morphology and content of WS₂ nanomaterials have a significant effect on the tribological properties of paraffin oil. The tribological performance of lubricating oil was best when the concentration of the WS₂ nanomaterial additive was 0.5 wt %. Moreover, the paraffin oil with added WS₂ nanoflowers exhibited better tribological properties than paraffin oil with added WS₂ hexagonal nanoplates. The superior tribological properties of WS₂ nanoflowers can be attributed to their special morphology, which contributes to the formation of a uniform tribo-film during the sliding process.