The Electrochemical Characteristics of Aluminum Galvanic-Anode Alloys in Seawater.
Interim progress rept. no. 10,
NAVAL RESEARCH LAB WASHINGTON D C
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Aluminum anodes have a theoretical ampere-hour-per-pound capacity approximately two and one-half times that obtained from magnesium anodes and approximately three and one-half times that obtained from zinc anodes. The actual current capacities in seawater, however, are determined by the electrochemical efficiency of the individual aluminum anode alloy. The electrochemical characteristics of several types of aluminum anodes under similar service conditions are discussed in the report and are compared to similar data obtained from zinc anodes and from aluminum anodes reported previously. Aluminum anodes containing mercury-zinc have consistently demonstrated current capacities in excess of 1250 ampere hours per pound. Under some exposure conditions large sections of these anodes might be lost before attaining their complete useful service-life. The indium-zinc aluminum anodes have a minimum current capacity of 757 ampere hours per pound. When operated at nominal in-service anode current density levels, other electrochemical characteristis were essentially equivalent to those of the zinc control anode. None of the tin-zinc aluminum anodes which apparently require a proprietary heat treatment for improved electrochemical characteristics had consistently high current capacities. It was also evident from this study that even commercial-size aluminum anodes in short-term experiments at high current densities do not predict the true long-term electrochemical characteristics in seawater. Author
- Properties of Metals and Alloys