Tribological performances of multilayer-MoS2 nanoparticles in water-based lubricating fluid

Abstract

Multilayer-MoS2 nanoparticles were dispersed in water-based lubricating fluid in a convenient and economical way. Oleic acid and triethanolamine were used as the main surfactants in this solution. Tribological performances of this fluid were tested under high pressure and high rotating speed. FEI Tecnai G20 TEM, Malvern Zetasizer Nano ZS were used to study the particle size and Zeta potential of the lubricants. Tribological performances of this water system with multilayer-MoS2 nanoparticles and the 3D-surfaces of wear scars after the experiments were analyzed by means of four-ball wear test machine and Olympus laser confocal microscope. According to Hertz theory and experimental data, it is practical significance to combine MoS2 nanoparticles with water-based lubricating fluid. Under high loading and high rotating speed the mixed suspension can provide good lubricating properties. On the basis of calculation the binding energy of layers in MoS2 nanoparticles is less than the energy of shearing in friction pairs. The layers in MoS2 nanoparticles slide in the process of friction. The best lubrication effects can be displayed when friction process lasts about 500 s.