In-situ electrochemical atomic force microscopy studies of aqueous corrosion and inhibition of copper

The corrosion of copper surfaces immersed in various electrolytes under potentiodynamic conditions at room temperature is studied by in-situ electrochemical atomic force microscopy (ECAFM). The ECAFM experimental settings used to study corrosion are discussed, and the composition of the different corrosion layers is identified by in-situ voltamperometric analysis. In sulfuric acid and sodium sulfate solutions, an important species displacement controlled via more or less complex dissolution - precipitation reactions is pointed out at the surface of the electrode. In addition, it is shown that this atomic movement irreversibly changes the relief of the metallic surface. Conversely, when the surface is passivated both in a borate solution and in a sodium heptanoate solution, the oxidation process at the metallic electrode is weaker and reversible. Moreover, the inhibiting action of sodium heptanoate is confirmed: a copper metallic soap overlayer appears on the surface via a dissolution-precipitation mechanism. (C) 2000 Elsevier Science S.A. All rights reserved.