A facile and effective method to improve the dispersibility of WS2 nanosheets in PAO8 for the tribological performances

The sedimentation of WS2 nanosheets in PAO8 is resolved by a facile method with the immobilization function of 1-methyl-2, 4-bis (N-octadecylurea) benzene (MOB), and tribological performances and mechanism of the composite lubricant are systematically investigated. Compared with blank PAO8, the composite lubricants have excellent tribological performance, which is attributed to the synergistic effect of WS2 and MOB. The immobilization function of MOB because of the network structure prevents the agglomeration and sedimentation of WS2 nanosheets. The boundary films, including tribochemical reaction film and physical absorbing film are formed on the surfaces of the friction pair during the friction process.