Influence Of Nb Addition On The Oxidation Behavior Of Novel Ni-Base Superalloy

Influence of Nb on oxidation behavior of novel Ni-base superalloy was investigated in detail at 1000 degrees C. Although alloy with 2 wt%Nb (2Nb) exhibits significantly higher weight gain than alloy without Nb (0Nb), oxide scale of 2Nb was more continuous and compact. In contrast, 0Nb underwent severe vaporization and spallation in oxide scale. Nb was found to accelerate the formation of compact TiO2 on Cr2O3 layer, leading to inhibited vaporization and spallation in oxide scale. Nb also accelerated the formation of continuous CrTaO4 layer beneath the Cr2O3, enhancing the oxidation resistance via inhibiting the interdiffusion of oxygen, nitrogen and metallic elements.