High temperature oxidation resistance of multilayered AlxTi1 − xN/CrN coatings

AlxTi1 − xN and CrN have been widely used as a protective coating material in many types of tools and mechanical components because of high wear performance and high temperature resistance. In this study, the high temperature oxidation behavior of Al0.63Ti0.37N and multilayered Al0.63Ti0.37N/CrN coatings was studied. These coatings were synthesized by a cathodic-arc deposition system with plasma enhanced duct equipment. The nanolayer thickness and alloy content of the deposited multilayered coating were correlated with the emission rate of alloy cathode materials. The multilayered Al0.63Ti0.37N/CrN coating revealed a laminate structure with stacking of Al0.63Ti0.37N and CrN layers, and the periodic thickness (Λ) was 16 nm. For the high temperature oxidation test, the coated samples were annealed in the temperature range of 700–1000 °C in air for 2 h. The multilayered Al0.63Ti0.37N/CrN possessed much thinner oxide layer thickness than Al0.63Ti0.37N. Even after oxidation at 1000 °C, the multilayered Al0.63Ti0.37N/CrN still retained their crystalline structure. An interface effect served as a barrier, and retarded the diffusion of oxygen into the multilayered Al0.63Ti0.37N/CrN. Thus, the multilayered Al0.63Ti0.37N/CrN showed a high temperature oxidation resistance superior to the Al0.63Ti0.37N.