The aim of this study is to gain information necessary to propose the mechanism of the oxide layers' formation on the FeCr alloy foil of 0.05 ram thickness as well as to obtain indications about thermal treatment resulting in the relatively uniform adhesive layers. The surface morphology of the oxide layers formed on the foil in the course of its thermal treatment as well as layers' thickness and element distribution along their cross sections were investigated with scanning electron microscopy and secondary ion mass spectrometry. Observed differences were ascribed to the various orientations of FeCr alloy crystallites. (c) 2005 Elsevier B.V. All rights reserved.