Role of the codeposited C and W element on the tribological performance of WS2 coating

Abstract

WS2 is a widely used solid lubricating material that exhibits applications in various fields, including automotive components, precision instruments, and key parts that require antiwear properties. However, WS2 is highly susceptible to humidity, which significantly limits its practical utility. In order to investigate and enhance the tribological and mechanical properties of WS2 coatings, a method involving codeposition of carbon (C) and tungsten (W) with WS2 was employed using magnetron sputtering, resulting in the successful preparation of W-diamondlike carbon (DLC)/WS2 composite coatings. Subsequent investigations revealed a synergistic effect of C and W through various methods. The addition of W noticeably improved both the nanohardness and Young’s modulus of the W-DLC coatings, thereby further enhancing the mechanical properties of the W-DLC/WS2 composite coatings and improving their wear resistance. However, it was observed that excessive W tended to oxidize, intensifying the abrasive wear of the composite coatings during friction. Moreover, Raman spectroscopy analysis indicated the presence of carbon in the composite coatings in the form of DLC, which served as a lubrication phase. The presence of DLC facilitated the formation of transfer films composed of graphite. Additionally, it was discovered that the number of graphite layers in the transfer films had an impact on the tribological properties of the coatings.