Cyclic Oxidation Resistance of Hot-Dipping Aluminized GH169

GH169 superalloy steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950 °C for 2h. The cyclic oxidation behaviors of the hot-dipped aluminized steel and GH169 were tested at 900 °C for 24 cycles using resistance furnace. Morphology of surface and cross-section, element distribution of the oxide scale were characterized by SEM and EDS. The results showed that protective Cr2O3 and Al2O3 oxide scales were formed on GH169 and aluminized steel after 24 cycles, respectively. The inner oxidation was found on GH169 after 24 cycles. It was composed of surface Al2O3 oxide film, outer Al-rich layer scattered with NiAl phase, and inner NiAl layer on aluminized steel after 24 cycles at 900°C.