Effect and role of alloyed Nb on the air oxidation behaviour of Ni-Cr-Fe alloys at 1000 °C

• DOI: 10.1016/j.corsci.2017.08.003
• Publication Date: 2017-08-10T15:31:08Z
• Authors: Ya-Xin Xu; Jin-Tao Lu; Xia-Wei Yang; Jing-Bo Yan; Wen-Ya Li
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract Ni-25Cr alloys alloyed with Fe (5 wt.% and 15 wt.%) and Nb (0, 1 and 2 wt.%) were designed and their oxidation behaviour was evaluated at 1000 °C. Results reveal that alloyed Nb has a positive impact on oxidation in both the kinetics and oxide scale structures. The parabolic rate constant k p of Nb-alloyed Ni-25Cr-15Fe alloys are nearly one-fourth the value for Nb-free alloy. The oxide scales change from spinel-included multi-layers in the Nb-free alloy to a much thinner Cr 2 O 3 single-layer in the Nb-alloyed alloys. NbC precipitates and slightly dissolved Nb account for these changes.