Synthesis of tungsten sulfide nanoparticles and their tribological properties as additives for lubricating oils

Abstract

Tetrathiotungstates with different alkyl groups have been synthesized by an exchange reaction between ammonium tetrathiotungstate and tetraalkylammonium halides. Synthesized samples are analyzed by elemental analysis and optical and thermal methods. Nano-WS₃ particles that are stable and soluble in nonpolar hydrocarbons are prepared by thermolysis of alkyltetrathiotungstates. The average particle size of nano-WS₃ is about 10–100 nm and depends on the nature of raw tetraalkylammonium halides. It is shown that nanoparticles of WS₃ are soluble in Vaseline oil (1–2 wt %) and exhibit antiwear activity.