Mechanism of anodic dissolution of intermetallic compound CdSb in concentrated KOH solutions

Anodic behavior of intermetallic compound CdSb is studied in concentrated solutions of KOH. Anodic oxidation of CdSb in 8.1 M KOH at potentials more negative than the equilibrium potential of antimony is shown to occur selectively by the electronegative component, cadmium. At more positive potentials, the primary selective dissolution of Cd is followed by a simultaneous ionization of both components. Upon reaching a certain concentration of ions of Sb(3+), anodic dissolution of CdSb in the near-electrode layer occurs concurrently with the reduction of these ions to metallic antimony, which forms own phase on the alloy's surface; i.e., there takes place pseudoselective dissolution.