Nano-multilayered ZrN‒Ag/Mo‒S‒N film design for stable anti-frictional performance at a wide range of temperatures

A multilayer film, composed by ZrN‒Ag (20 nm) and Mo‒S‒N (10 nm) layers, combining the intrinsic lubricant characteristics of each layer was deposited using DC magnetron sputtering system, to promote lubrication in a wide-range of temperatures. The results showed that the ZrN‒Ag/Mo‒S‒N multilayer film exhibited a sharp interface between the different layers. A face-centered cubic (fcc) dual-phases of ZrN and Ag co-existed in the ZrN‒Ag layers, whilst the Mo‒S‒N layers displayed a mixture of hexagonal close-packed MoS2 (hcp-MoS₂) nano-particles and an amorphous phase. The multilayer film exhibited excellent room temperature (RT) triblogical behavior, as compared to the individual monolayer film, due to the combination of a relative high hardness with the low friction properties of both layers. The reorientation of MoS₂ parallel to the sliding direction also contributed to the enhanced anti-frictional performance at RT. At 400 ℃, the reorientation of MoS₂ as well as the formation of MoO₃ phase were responsible for the lubrication, whilst the hard t-ZrO₂ phase promoted abrasion and, consequently, led to increasing wear rate. At 600 ℃, the Ag₂MoO₄ double-metal oxide was the responsible for the low friction and wear-resistance; furthermore, the observed transformation from t-ZrO₂ to m-ZrO₂, could also have contributed to the better tribological performance.