Abstract: The composite films of W/Diamond like carbon (DLC) were prepared on the surface of high speed steel HAP40 by magnetron sputtering. A 5 μm thick composite films (W layer: 1.7 μm; W_XC_Y layer: 0.3 μm; DLC layer: 3 μm) was obtained by adjusting the process parameters. The structure, cross-sectional morphology and friction and wear properties of W/DLC composite films are mainly studied. The results show that the existence of W and W_XC_Y composite layer is benefit to reduce the growth stress of DLC layer and improve its interface bonding. The main wear form of W/DLC composite films is sliding wear which does not adhere aluminum powder, but it would absorb oxygen atom from the air or lubricating oil. There are a lot of hydrogen saturated σ-dangling bonds in W/DLC composite films, which passivates the surface of the composite film and leads to low friction coefficient.

Key words: Magnetron sputtering, Diamond-like carbon film, Composite films, Friction and wear, Surface passivation