High temperature oxidation of ion-plated CrN films

The high-temperature oxidation of CrN films which were deposited onto stainless steel substrates using an arc ion plating apparatus was studied at temperatures ranging from 1023 to 1173 K for 0.6 to 480 ks in air. The oxidation rate obtained from mass gain as a function of time was found to fit well to a parabolic time dependence. Formed oxide layers were analyzed by XRD, SEM, and SAM. An activation energy of the oxidation of CrN was slightly lower than that of the self-diffusion coefficient of Cr ion in Cr₂O₃. It is concluded that the oxidation of CrN is controlled by the outward diffusion of Cr ions through the Cr₂O₃ layer formed on each CrN grain.