Microstructure and tribological properties of sputtered MoSx-W composite films supported by porous alumina aperture array

Aluminum alloys are widely used in the aerospace and automotive industries due to their high strength and low density but also suffer from poor wear resistance. The employment of stable solid lubricants on aluminum alloys will be beneficial for their service life under load-bearing conditions. In this paper, MoSx-W composite coatings were deposited on porous anodic aluminum oxide (AAO)/Al substrates. The effects of tungsten content on the film structure and friction properties were systematically investigated. It is found that tungsten exists as metallic particles within the MoSx matrix, forming a system of hardness phase reinforced soft matrix. With the increase of W content, the film morphology transforms from nano-flower-like to ball-like, associated with an obvious enhancement of film density as well as hardness. The latter prolongs the service life of MoSx films from 10 min only in untreated specimen to 88.8 min in composite sample. Finally, the improvement of wear performance upon tungsten loading was discussed in detail.