Preparation of chromium oxynitride and chromium nitride films by DC reactive magnetron sputtering and their material properties

Abstract

Thin films of ∼2 μm thick chromium nitride (CrN) were prepared by direct current (dc) reactive magnetron sputter deposition on steel substrates. XPS spectra showed the presence of chromium in the form of CrN with traces of Cr₂O₃ on CrN thin films. XRD spectrum shows CrN peaks at 37 and 43° which corresponds to (111) and (200) planes. Surface topography from atomic force microscope shows that films have continuous coverage of rectangular cell like patterns. Corrosion performance of these films on low carbon steel substrates in 3·5%NaCl solution was evaluated using electrochemical techniques. A less negative value of E _corr and lower value of I _corr signify an improvement in corrosion resistance of the CrON coating. Scanning vibrating electrode technique (SVET) was able to discretely map relative cathodic and relative anodic sites at a macroscopic defect and to record the changes of local electrode activities in a real time.