Pulsed DC magnetron sputtered MoSx-TiN composite coating for improved mechanical properties and tribological performance

This work reports on the morphological, mechanical and wear properties of MoSx-TiN composite films, deposited by closed-field unbalanced magnetron sputtering (CFUBMS) process applying pulsed DC power supply simultaneously to the targets and substrate bias. The structure of the coating was studied using grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) microanalysis. EDX analysis showed presence of around 30% Ti in the composite matrix. Presence of MoSx peak in GIXRD profile confirmed the presence of MoSx as a compound, not as elemental Mo and S. One improvement of the composite architecture was attempted by combining the composite architecture with hard TiN underlayer and soft MoSx top layer. The adhesion, hardness and wear properties were studied by scratch test, Rockwell and Vickers indentation and pin-on-disc test respectively. Adhesion was found to be improved in the composite architecture compared to pure MoSx and TiN coating. The composite architecture also showed superior tribological performance as compared to pure MoSx and TiN coatings.