Pitting corrosion of copper. equilibrium - mass transport limitations

摘要

Predictions from a mathematical model of the propagation of a corrosion pit in copper are reported. The model uses equilibrium data for solid and aqueous species to calculate local chemical and electrochemical equilibria in small volume elements. Mass transport between elements under local internal equilibrium is calculated using aqueous diffusion coefficients with the constraint of electrical neutrality. Propagation of a corrosion pit is deemed possible when the fraction of the oxidised copper that forms solid corrosion products, at the copper metal, is insufficien to completely cover teh underlying metal. The effect of pH and salt concentrations in the bulk water was studied by varying the composition of the water.