Structure controlling strategy towards the high-temperature oxidation in multilayered coatings: an experience from Cr/CrAlN system

Abstract

Cr/CrAlN multilayered coatings with layer thickness h ranging within 20–500 nm were prepared on Zircaloy-4 and then oxidized in a 1000 °C steam environment. The oxidation resistance of coatings improved significantly with the increasing h, which is derived from the evolution of surface oxides from Cr2O3 to α-Al2O3. Larger h can provide a better barrier effect for Al diffusion and help maintain a locally higher Al concentration near the surface, which is favorable for the formation of an α-Al2O3 layer. The oxidation process was analyzed to deepen the understanding of the oxidation behavior in this and other similar systems.