Effect of Al and Zr Alloying on the Oxidation Behaviors of Cr in High Temperature Oxygen Environment

Abstract

A series of CrAl and CrAlZr alloy blocks with different Cr/Al ratios were prepared by powder metallurgy method. The alloys were oxidized at 800℃ for 30 hours. Results showed that a compact oxide layer was formed on the surface of CrAl alloy, showing good oxidation resistance. However, the introduction of Zr act as a fast diffusion path for oxygen, where the underlying alloy was oxidized seriously. The experiment has demonstrated that the formation of ZrO2 undermines the completeness of the compact Cr2O3 and Al2O3 oxide layer, which is the dominate factor for the failure of the CrAl alloy.

Keywords: High temperature oxidation, Alloy block, Al concentration, Zr concentration