CORROSION AND ANODIC BEHAVIOR OF ZINC AND ITS TERNARY ALLOYS IN ALKALINE BATTERY ELECTROLYTES

Several attempts are being made to avoid the use of mercury-bearing zi nc/zinc alloys as anodes in alkaline power sources. The work presented here suggests the possible use of some ternary alloys based on zinc o f purity 99.9 to 99.95 wt.% as anodes in 10 M NaOH solution with sodiu m citrate, sodium stannate and calcium oxide as complexing agents and inhibitors. The corrosion of zinc and its alloys in 10 M NaOH solution is under cathodic control; in other alkaline electrolytes, it is unde r anodic control. Anode efficiency of up to 99.0% is achieved. The cor rosion rates of zinc and its alloys are found to be comparable with th ose of mercury-bearing zinc in the chosen electrolytes. It is conclude d that both dry cells and Zn-air batteries can be constructed with the above anodes and alkaline electrolytes. Thus, the presence of mercury , either in the anode or in the electrolyte, is avoided.