Effect of surface geometrical configurations induced by microcracks on the electron work function

Fracture or failure of materials usually results from the initiation and propagation of microcracks. In particular, surface behavior of a material such as wear and/or corrosion depends strongly on the geometry of microcracks. In this study, the effect of microcrack configurations on the local surface electronic activity, which can be represented by the electron work function (EWF), were investigated using the theoretical approach and the Kelvin probing technique. We proposed a micro capacitor model to calculate variations of the EWF with respect to the geometrical parameters of microcracks. It was demonstrated that the EWF depended strongly on the position, angle and orientation of microcracks. Using a scanning Kelvin probe, measurements of the EWF were conducted to verify the theoretical calculations. The experimental observations showed basic agreement with the calculated results. This model could be useful for thorough understanding of the electronic mechanisms responsible for electrochemical and mechanochemical behaviors of a surface containing microcracks. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.