Influence of surface morphology on corrosion and electronic behavior

Electrochemical or mechanochemical behavior of a surface, such as corrosion or corrosive wear, is extremely complicated and involves various chemical, physical and mechanical factors. To gain a thorough insight into such a complex phenomenon, it is necessary to understand the role of each factor. In this study, the influence of surface morphology, represented by roughness, on the corrosion and electronic behavior, represented by the electron work function (EWF), of copper was investigated using an atomic force microscope and a scanning Kelvin probe. Experimental results showed that the corrosion rate increased with an increase in surface roughness, whereas its surface EWF decreased. It was theoretically demonstrated that roughness can decrease the average EWF but increase the fluctuation of the local EWF. Such fluctuation could promote the formation of microelectrodes and, therefore, accelerate corrosion. The study demonstrates that the surface morphology can make a considerable contribution to corrosion and thus corrosive wear. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.