Production of NiAl-(Cr,Mo) Eutectic Alloys and Their Cyclic Oxidation Behavior at 800-1000 degrees C

Abstract

Ni-33Al-34Cr and Ni-33Al-28Cr-6Mo (at %) eutectic alloys were produced by the resistive sintering (RS) technique using elemental powders. The cycle oxidation behaviors of alloys at 800, 900, and 1000 degrees C for 168 h in air atmosphere were investigated. The oxidation resistance of alloys was evaluated by the weight change measurements. The activation energy for NiAl-34Cr and NiAl-28Cr-6Mo alloys was 57 and 31 kJ mol(-1), respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were performed to characterize the initial microstructure and the oxidation products. The obtained results showed that the oxidation products mainly consist of Cr2O3, alpha-Al2O3, NiO, and NiAl2O4 oxides.