Preparation of NiMoO2S2 nanoparticle and investigation of its tribological behavior as additive in lubricating oils

Nickel oxythiomolybdate (NiMoO2S2) nanoparticles with an average size of 13 nm were synthesized in the microemulsion system of sodium dodecyl-sulphate (SDS)/isopentanol/cyclohexanene/water. The tribological performances of the prepared NiMoO2S2 nanoparticles as a lubricating additive were evaluated in four-ball wear tester and a pin-on-disc tester at elevated temperature. The results showed that NiMoO2S2 nanoparticles as additive exhibit very good EP behavior and possess good anti-frictional performance with a smooth transition from fluid film lubrication at low temperature to solid film lubrication at elevated temperature, which could fit the needs of lubrication at large temperature range.