Surface analysis of electrochemically stripped CrN coatings

CrN multilayer coatings are possible replacements for hard chromium because of their good mechanical and chemical properties. This paper focuses on X-ray photoelectron spectroscopy (XPS) to study the mechanism of electrochemical stripping of multilayered Cr–N based coatings. The samples were produced by electron beam (e-beam) physical vapour deposition (PVD), on mirror polished M2 steel. Multilayers constituted three separate layers of CrN with intermediate interlayers of Cr (0.1 μm). The total coating thickness was in the range 4.5–5.5 μm. Under galvanostatic conditions, anodic oxidation of CrN leads to replacement of nitrogen in the CrN coating by oxygen, forming oxy-nitrides on the samples surface. Contrary to findings described by some authors, we have not detected Cr6+ in this research.