Magnetron-sputtered copper/diamond-like carbon composite thin films with super anti-corrosion properties

Abstract

Super anti-corrosive copper/diamond-like carbon (Cu/DLC) composite films are applied on mild steel utilizing magnetron sputtering in a mixed atmosphere of Ar and CH4. Mechanical, contact angle, and corrosion performance of the resulting Cu/DLC thin films are probed and discussed in terms of Ar/CH4 and Cu/C ratios. Overall, Cu/C ratio has augmented by Ar/CH4 ratio. Raman spectra of films revealed typical features of G and D bands indicating formation of DLC phase. The Cu/DLC thin films with higher Cu content exhibited a higher degree of sp2 carbon clustering, but lower diamond-like sp3 bonding. Internal stress values of Cu/DLC thin films decreased with increasing Cu/C ratio. Addition of a few amount of Cu to DLC resulted in a rise in plastic hardness and H3/E2 ratio of Cu/DLC composite thin films, but optimum value was observed for composite films having an intermediate Cu concentration. The contact angle of iron substrate increased when coated with Cu/DLC thin films, but Cu content of films played a minor role. The Cu/DLC thin films formed via magnetron sputtering revealed super anti-corrosion performance, the term which is defined, conceptualized, and quantified in the current study.