Deposition and characterization of multi-principal-element (CuSiTiYZr)C coatings

Multi-principal-element (CuSiTiYZr)C coatings were prepared by co-sputtering of pure Cu, Si, Ti, Y and Zr targets in an Ar + CH4 atmosphere, for different CH4/(CH4 + Ar) flow rate ratios (0.25; 0.35; 0.50). The films were analyzed for elemental and phase composition, crystalline structure, morphology, mechanical characteristics, corrosion resistance and tribological performance. Ternary (TiZr)C coatings were also examined for comparison. The (CuSiTiYZr)C coatings were found to be amorphous, whatever the CH4/(CH4 + Ar) ratio. For all the coatings, an increase in the carbon content led to an improvement of corrosion resistance, mechanical and tribological film characteristics, mainly due to the formation and development of an amorphous free-carbon phase. The (CuSiTiYZr)C coatings exhibited superior corrosion and wear behaviour, when comparing to (TiZr)C reference coatings with similar carbon content. The highest hardness (29.5 GPa), the lowest friction coefficient (∼0.15) and the best wear-corrosion resistance were measured for the (CuSiTiYZr)C coating with carbon/metal ratio of about 1.3 (CH4/(CH4 + Ar) flow rate = 0.50).