Correlation Between Voltammetry of Immobilized Particles and Mott-Schottky Analysis of Metal Corrosion Patinas

The conjoint application of the voltammetry of immobilized particles (VIMP) methodology and the Mott-Schottky analysis (MS) of impedance data to studying metal corrosion patinas is described. The study is applied to copper and bronze objects exploiting the semiconducting character of cuprite and other copper corrosion products. A simplified theoretical modeling of MS analysis at microparticulate deposits extracted from metal corrosion layers attached to graphite electrodes is provided. The proposed model compensates for the disturbing effect of the regions of the basal electrode directly exposed to the electrolyte. Alternative models accounting for the variation of the density of charge carriers with depth are tested as well as the correlation between VIMP and MS data with reasonably satisfactory results.