Thermal stability enhancement of Cr2AlC coatings on Zr by utilizing a double layer diffusion barrier

Abstract

Decomposition of Cr2AlC deposited onto a Zr substrate and vacuum-annealed is observed at 800 °C as Al diffuses from the MAX phase into the Zr substrate. A double layer of ZrN and AlN has been predicted by CALPHAD calculations to act as diffusion barrier between the Zr substrate and Cr2AlC. Experimental thermal stability investigations corroborate this prediction by confirming that the proposed double layer diffusion barrier coatings suppress the decomposition of Cr2AlC for one hour at temperatures of up to 1000 °C.