The molten salt-induced oxidation/sulfidation (hot corrosion) on nickel aluminide intermetallic compound (Ni 3Al, Ni–11.7 wt.%Al–0.6 wt.%Zr–0.01 wt.%B) has been studied in the 1%SO 2/air gas mixtures. X-ray analyses for the hot-corroded specimen tested at different period of time show only NiO formed at 605 °C, and NiO and NiAl 2O 4 at 800 and 1000 °C. EDAX analyses reveal that AlS x and/or NiS x are produced beneath the oxide scales at all temperatures. From the experimental results, the hot corrosion mechanism can be described as follows. NiO oxide formation consumes oxygen in molten salt. The consumption of oxygen will locally reduce the oxygen and increase the sulfur partial pressure in molten salt. This partial pressure change can be represented by the stability diagram. As the increased sulfur partial pressure reaches the equilibrium partial pressure region of NiS x and/or AlS x , NiS x and/or AlS x will form at the salt/alloy interface through sulfidation reaction. The consumption of sulfur will balance out the sulfur and oxygen partial pressure increases in molten salt. This will force NiO to form again. This process also suggests that NiO and NiS x and/or AlS x will be produced simultaneously. Since the produced sulfide is thermodynamically unstable when the oxygen potential increases, it is possible for sulfide to convert into oxides (NiO, Al 2O 3, and NiAl 2O 4) through the necessary reactions. There are two possibilities for the formation of spinel phase, which is produced either through the reaction of Al and Ni with oxygen in the molten salt or through the evolution of sulfides.