Auger characterization of the surface oxidation of austenitic Fe-26Mn-7Al-0.9C alloy

Austenitic Fe-26Mn-7Al-0.9C alloy was exposed to oxygen at various doses from 200-800°C. Low-energy Auger transitions were used to characterize the oxide layer formed on this alloy surface during oxidation at the above temperatures. The results showed that Fe-oxide was predominantly formed on the alloy surface on exposure to oxygen at 200°C. However, aluminum oxide tends to form on the alloy surface for low oxygen exposure of 10 L at 300°C. For higher oxygen doses at 300°C, Al reacts with oxygen initially to form an Al-oxide followed by the Fe-oxide nucleation. Furthermore, the Auger observations revealed that selective oxidation of aluminum predominantly occured on the alloy surface at 400 and 600°C. However, no oxidation process occured on the alloy surface at 800°C due to the impurity S segregating to the alloy surface and apparently blocking all sites thus preventing any oxygen adsorption. © 1991.