THE EFFECT OF ANTIMONY ON THE ANODIC BEHAVIOR OF LEAD IN SULFURIC-ACID-SOLUTIONS .1. VOLTAMMETRIC MEASUREMENTS

The influence of Sb on the formation of the corrosion layer on Pb has been studied with a Pb-12%Sb alloy electrode in sulphuric acid solution using the ring-disk technique, potential decay measurements and galvanostatic oxidation. It was found that in the voltammograms of the Pb-Sb electrode a new cathodic peak appears, compared to pure Pb, after oxidation at constant potentials > 0.8 V, showing that a new oxidation product is formed. The stoichiometry of this product changes gradually with potential approaching that of PbO2 at high anodic potentials. This product also improves the electronic conductivity of the corrosion layer. The effect of Sb(III) or Sb(V) dissolved in the electrolyte on the formation of this Sb containing product on pure Pb was similar to that of Sb as an alloying agent. It is suggested that this new product is on pure Pb (most probably nonstoichiometric) doped with Sb or a mixed Pb-Sb oxide.