Preparation and tribological properties of WS2 and WS2/TiO2 nanoparticles

A method was developed to prepare WS2 and WS2/TiO2 nanoparticles. A blue tungsten oxide precursor was synthesized from Na2WO4, CH3CSNH2, and HCl. WS2 nanoplatelets was produced after sulfurizing the precursor at 300 °C. Nano-TiO2 could be activated by HCl and provide active sites for the deposition of the precursor to produce WS2/TiO2 nanoparticles after sulfurization. The as-prepared two nano-additives slightly affected the friction reduction of diisooctyl sebacate (DOS), but they, especially WS2/TiO2, remarkably improved the wear resistance of DOS. Compared with the pure DOS, the 0.75% WS2/TiO2-containing DOS decreased the wear volume by ∼81%. The anti-wear performance of WS2/TiO2 is ascribed to the formation of a lubricating film and the synergistic lubrication effect of WS2 and TiO2.