Though a magnesium based alloy (ASTM AZ63) is used as a galvanic anode for soil and freshwater environment, it was not possible to use under the environment of the extremely high resistivity, because there is chloride ion concentration dependence in the potential of the galvanic anode. We succeeded in the development of new magnesium anodes that show higher performance than that of AZ63. The new magnesium-based anodes showed a high current efficiency compatible to that of AZ63 in both field and laboratory tests of constant current electrolysis. Limit of application of galvanic anode method is expected to expand because of the positive anode potential and high current efficiency that brings about high-performance and prolonged anodic life. In the design of cathodic protection in high resistivity media a decrease in the number of mounting anodes is expected by the use of the high-performance magnesium compared with the case of conventional AZ63, which will lead to the cost reduction in the future.

Subject
Noble potential, Current efficiency, Marine environments, Galvanic anodes, Anode potential, Chloride ion concentration, Zinc anodes, Magnesium anodes, Installation, Anode resistance, Current densities, Soil, Anodes
Keywords:
cathodic protection, galvanic anode, magnesium anode, AZ63, soil, freshwater, cathodic protection design, high resistivity environment
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2006
Association for Materials Protection and Performance (AMPP)
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