Corrosion behaviors of Cr(N,O)/CrN multi-layered coatings by cathodic arc deposition

Cr(N,O)/CrN based coatings were produced in the form of double-layered and four-layered structures, by the cathodic arc deposition process. These coatings were deposited onto tool steel substrates. The phase structure and morphology of coatings were observed by utilizing XRD, XPS and SEM. The corrosion behavior of these coatings was investigated using polarization tests, carried out in the solution of 1 M H2SO4 solution. The SEM surface topography showed a smoother surface of the four-layered Cr(N,O)/CrN coating compared to that of CrN and Cr(N,O)/CrN double-layered coatings. The corrosion resistance of Cr(N,O)/CrN four-layered coatings with thinner thickness was better than that of CrN single-layered and Cr(N,O)/CrN double-layered coatings, since pinholes in the coatings were effectively blocked by multi-layered structure.