Effect of MnO4- and silver content on electrochemical behaviour of Pb-Ag alloy anodes during potential decay periods
(1. School of Metallurgical Engineering, Hunan University of Technology, Zhuzhou 412007, China;
2. Department of Mining, Metallurgy and Material Engineering, Laval University, Ste-Foy, Quebec, G1K 7P4, Canada;
3. China National South Aviation Industry Co. Ltd., Zhuzhou 412002, China;
4. LTE, Hydro-Quebec, 600 Avenue de la Mortagne, C.P. 900 Shawinigan, QC, G9N 7N5, Canada)
2. Department of Mining, Metallurgy and Material Engineering, Laval University, Ste-Foy, Quebec, G1K 7P4, Canada;
3. China National South Aviation Industry Co. Ltd., Zhuzhou 412002, China;
4. LTE, Hydro-Quebec, 600 Avenue de la Mortagne, C.P. 900 Shawinigan, QC, G9N 7N5, Canada)
Abstract: The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag- 0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4- ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with , the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag- 0.1%Ca by the electrochemical impedance spectroscopy (EIS) analysis.
Key words: electrochemical behaviour; Pb-Ag anode; permanganate ion; potential decay periods; zinc sulphate electrolyte