Effect of Ag Content and β-PbO₂ Plating on the Properties of Al/Pb-Ag Alloy

Due to the excellent electrical conductivity and mechanical properties, Al/Pb-Ag alloy has a great potential to be used as an alternative anode for zinc electrowinning. In this work, the effects of Ag content and surface plating with β-PbO₂ on the anodic behavior and reaction kinetics were investigated by cyclic voltammetry (CV), anodic polarization curves, electrochemical impedance spectroscopy (EIS) and corrosion rate test. The phase composition and microscopic morphology of the anode oxide layers after electrolysis were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results indicate that high content of silver and electroplating β-PbO₂ layer can increase the oxygen evolution activity, electrocatalytic activity and corrosion resistance of the anodes. Al/Pb-0.75%Ag plating β-PbO₂ has the lowest oxygen evolution overpotential followed by Al/Pb-0.3%Ag plating β-PbO₂, Al/Pb-0.75%Ag and Al/Pb-0.3%Ag. Besides, high content of silver is more beneficial to improving corrosion resistance compared with electroplating β-PbO₂ on anode. In addition, the phase composition of four anodes layer are mainly composed of α-PbO₂, β-PbO₂, Pb and PbO.