PREPARATION BY ION-BEAM-ASSISTED DEPOSITION, ANALYSIS AND TRIBOLOGICAL BEHAVIOR OF MOS2 FILMS

Thin (100-600 nm) dual-layer MoS2 solid lubricating films were deposited on steel and ceramic substrates by ion beam sputtering with ion beam assistance. Stoichiometry was controlled by means of added sulfur from a separate target. Films prepared under various conditions were analyzed for composition and structure and were evaluated in dry and humid environments for sliding friction and endurance. Friction coefficients were low (less than 0.05) and endurances high in dry air, but these were degraded by moisture. The processing parameters and the ratio of sulfur to molybdenum had only small effects on endurance, and almost no effect on friction. The MoS2 layers were compact and partially amorphous, becoming crystalline after annealing, with basal planes usually parallel to the surface. These films appear promising as lubricants for steel or ceramic surfaces in dry or vacuum environments.