Two micro-electrode techniques, scanning electrochemical microscopy (SECM) and the micro-capillary cell (MCC) technique, were used to investigate corrosion behaviour of a polycrystalline iron surface in acidic sulphate media. Local corrosion reactivity was found to be strongly dependent on crystallographic orientation of the surface as well as measurement conditions. Results obtained by using microelectrode techniques are expected to reveal all aspects of corrosion behaviour of the surfaces of polycrystalline materials including iron. (C) 2013 Elsevier Ltd. All rights reserved.