Isothermal Oxidation Behavior of Haynes 230 Alloy in Air at 1100 °C

The isothermal oxidation behavior of Haynes 230 alloy (Ni-Cr-W-Mo alloy) in air at 1100 °C was investigated by means of SAXD and SEM (EDAX). The predominant phase in the oxide scales were Cr2O3 and (Ni, Mn, Cr)3O4. Multilayer was observed with increasing of oxidation time. The outer (Ni, Mn, Cr)3O4 scale may reduce the volatilization of inner Cr2O3 scale and its oxidation behavior almost followed parabolic law. Due to preferential diffusion of manganese and chromium, alloy composition beneath the oxide scale changed, which led to subsurface degradation such as intergranular oxidation, void formation, and no carbide zone formation.