The stability of Fe-Cr alloys was investigated in H-2-H2O atmosphere at 1073 K for solid oxide fuel cell (SOFC) interconnects. Oxide scale layers formed at the surface of Fe-Cr alloys changed the surface morphology of the alloy. The phases identified by X-ray diffraction were spinel oxides and Cr2O3 at the surface. The diffusion profiles of several major and minor elements were measured by secondary ion mass spectrometry in its depth profile mode. The distribution of cations was in the following order from the free surface: Mn-, Fe-, La-rich layer --> Cr-rich layer ! Si-rich layer --> Al2O3 inner oxides and alloy. The growth rate of the scale layer was determined from the thickness of the scale with a parabolic growth relationship: x(2) (mum(2))=3.6 x 10(-6) (mum(2) s(-1)) x t(s). (C) 2003 The Electrochemical Society.