Tribological properties of MoS2/metal composite coatings under different humidity

Cr or Ti doped MoS2 coatings with different Cr or Ti content were deposited on high speed substrate by magnetron sputtering deposition. The tribological properties of the coatings were tested against alumina ball at different loads and different humidity using ball-on-disc wear test. The morphology, composition, microstructure, mechanical properties were analysed using scanning electron microscope (SEM), energy dispersive spectroscopy of X-ray (EDX), X-ray diffraction (XRD), nanoindentation, respectively. The results show strong dependency of the tribological properties on the Cr or Ti content in the as-deposited coatings. A lower level of Cr or Ti doping can increase the hardness of the coating, the tribological properties in humid condition are also evidently improved as compared to pure MoS2. The improvement is more pronounced at higher loads. 10 at.% is found to be the optimal level that presents excellent anti-friction and anti-wear properties for both MoS2-Cr coatings and MoS2-Ti coatings. The excellent tribological properties are found to be due to their ability to form a stable transfer layer on the surface of the counterbody in humidity conditions, and the layer supply lubrication for the contact surface.Bachelor of Engineering (Materials Engineering