Oxidation of Fe-10Cr in O2 and in O2+H2O environment at 600 °C: A microstructural investigation

Oxidation of Fe-10Cr in dry and wet O-2 was studied at 600 degrees C for up to 168 h. Oxide microstructure was investigated by STEM/EDX, FIB/SEM and TEM. Oxidation in dry O-2 gives a Cr-rich protective (Fe1-xCrx)(2)O-3 scale. The same protective oxide initially forms in O-2 + H2O environment, but after an incubation period scale breakdown is triggered by CrO2(OH)(2) evaporation that depletes the substrate in Cr and converts (Fe1-xCrx)(2)O-3 to FeCr spinel oxide. Internal oxidation occurs after breakaway. Alternating external and internal oxidation result in the inward-growing scale showing a characteristic banded morphology. (C) 2013 Elsevier Ltd. All rights reserved.