Synthesis of oil-soluble WS2 nanosheets under mild condition and study of their effect on tribological properties of poly-alpha olefin under evaluated temperatures

A liquid phase method was adopted to encapsulate tungsten disulfide (WS2) nanosheets with oleylamine (OA) at a relatively lower temperature of 200 degrees C so as to acquire good solubility in organic lubricant base oil. The effect of OA-modified WS2 nanosheets on the tribological properties of poly-alpha olefin (PAO6) in a wide temperature range was examined with a four-ball machine and a UMT TriboLab test rig in a piston ring-cylinder liner contact mode. Results indicate that the OA-modified WS2 nanosheets added in PAO6 oil are able to improve the tribological properties of the lubricant base oil significantly at elevated temperatures; and they are advantageous over zinc dialkyldithiophosphates in improving the anti-wear ability of PAO6 from room temperature to 300 degrees C.