Formation and characterization of DLC:Cr:Cu multi-layers coating using cathodic arc evaporation

Chromium and copper-doped diamond-like carbon (DLC:Cr:Cu) films were deposited on SKH 51 tool steel. We have prepared multilayers of DLC:Cr and DLC:Cu by cathodic arc evaporation process using chromium (Cr) and copper (Cu) target arc sources to provide Cr and Cu in the DLC. Acetylene reactive gases were also activated at a pressure of 5 mTorr to 25 mTorr and a temperature fixed at 180 °C to provide the DLC. The resulting DLC:Cr:Cu film contained CrxCuy as well as CrxCy nanoparticles vital for the film mechanical properties. The crystal structure was investigated using X-ray diffraction (XRD) and transmission electron microscopy, while the surface morphology and chemical composition were studied by field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The process parameters were compared by studying the various mechanical properties of the films such as microhardness and residual stress. The result of this process enhanced the DLC:Cr:Cu composite coatings for high toughness and lower friction coefficient (0.08). The profiles of sp3/sp2 (XPS) ratios corresponded to the change of microhardness profile by varying the pressure of the hydrocarbon gases (C2H2).