Enhancement of friction performance of fluorinated graphene and molybdenum disulfide coating by microdimple arrays

Abstract

Two-dimensional (2D) materials, including graphene-family materials and molybdenum disulfide (MoS2), have been used as solid lubricants because of their low interlayer shear strength. In this study, a fluorinated graphene (FG)–MoS2 nanocomposite coating was deposited on a stainless-steel substrate with a laser surface textured dimple array. The FG–MoS2 nanocomposite coating deposited on a textured surface led to the reduction in the coefficient of friction to 0.036, and it significantly reduced wear and extended the lifetime compared with those obtained using the MoS2 coating. The excellent tribological performance is attributed to the synergetic effect between FG and MoS2 nanoflakes and the function of texture, where the MoS2 nanoflakes dominate the lubrication performance because of interlayer shearing, and the FG nanoflakes suppress the influence of external humidity on MoS2 nanoflakes because of their hydrophobic nature. Meanwhile, the textured surface can promote the formation of a tribofilm through changing the stress distribution at the sliding interface and act as a reservoir for nanoflakes, leading to a much lower friction and longer lifetime. This has implications for the development of functional surfaces with excellent lubrication and wear-resistance performances with 2D materials.