Sandvik Sanergy HT is considered as an interconnect material for PCFC and SOFC. In this work corrosion of Sandvik Sanergy HT was studied under simulated fuel cell conditions in a dual atmosphere setup, with air on one side and hydrogen on the other. Both the microstructure and the composition of the oxide scales grown in air were significantly altered by dual atmosphere. The Fe concentration in the oxides increased; the highest Fe concentration was found in oxides formed in air with dry 5% H-2 + Ar on the other side of the sample. The effects of dual atmosphere conditions became more pronounced by increasing the duration and the reaction temperature. Variations in the oxidation behavior are discussed in the view of hydrogen transport through the interconnect material, and its influence on the outward metal transport and oxide scale growth. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.