High temperature oxidation of a CrN coating deposited on a steel substrate by ion plating

A Cr 0.644N 0.356 coating was deposited on a steel substrate by arc-ion plating. The oxidation characteristics of the deposited coating, which was composed of CrN and Cr 2N phases, were studied at temperatures ranging from 700 to 950°C in air. The coating displayed good oxidation resistance up to 950°C. The oxidation product was primarily Cr 2O 3, which contained some dissolved nitrogen and the substrate element of iron. The unreacted coating beneath the oxide scale had some dissolved oxygen and iron. The oxidation of the Cr 0.644N 0.356 coating occurred via complex routes such as predominant outward diffusion of chromium, nitrogen and iron and inward transport of oxygen.