Fracture in MoS 2 solid lubricant films

Abstract

The fracture properties of sputter-deposited films of MoS 2 as a function of the additive-controlled microstructure were assessed using brale indentation contact and scanning electron microscopy (SEM). Additives were incorporated as either co-sputtered species (Ni, SbO x ) or as multilayers (Au-20% Pd, Ni). Undoped films were also examined as references. The undoped films and 3% co-sputtered Ni films (deposited at 2.66 Pa argon background pressure) showed zone 2 columnar plate morphologies with porosity. Co-sputtered films having higher concentrations of Ni or SbO x showed zone 1 dense cauliflower morphologies, while the multilayer films (and pure MoS 2 films deposited at 0.266 Pa) exhibited dense, featureless morphologies. The porous zone 2 films generally resisted delamination better than the denser morphologies. High Ni concentrations increased spallation. The presence of SbO x affected fracture propagation and appeared to be more benign than Ni. The presence of multilayers also affected fracture and retarded spallation in dense microstructures. However, many multilayer structures showed significant delamination.