Electrochemical behaviour of lead alloys as anodes in zinc electrowinning

The electrochemical and corrosion properties of the ternary and quaternary lead alloys Pb-0.18Ag-0.012Co. Pb-0.2Ag-0.06Sn-0.03Co, and Pb-0.2Ag-0.12Sn-0.06Co (wt-%) have been investigated. The formation of oxide layers on the surface of these alloys was traced by cyclic voltammetric methods and the composition of the anodic oxide layers was determined by X-ray and SEM analyses. The cobalt inclusions reduce the anodic polarisation and improve the corrosion resistance of the alloy. The Pb-0.2Ag-0.12Sn-0.06Co alloy displays electrochemical and corrosion properties similar to those of Pb-1Ag and can be used us a substitute for the latter as a material for anodes in the electrowinning of zinc from sulphate electrolytes.