Zn-Al alloys, prepared by the addition of 0.04-1.5% Al to various grades of commercial zinc respectively, were tested fundamentally regarding the behaviors as galvanic anodes in sea-water.
Small pieces of samples were tested as anodes in artificial sea-water at room temperature for more than 1, 000hrs, maintaining the anodic current at the current densities of 1.0 and 0.3mA/cm
2 constantly. Through the test, anodic potentials were frequently observed, and finally weight losses of anodes were determined.
Experimental results obtained shows that the addition of a small amount of Al to lower-purity zinc is extremely effective to eliminate the tendency to become passive, which has been considered the fatal defect of those made of such impure zinc.
It has been also confirmed that the anode efficiency somewhat increases with the addition of 0.1-0.50 Al, but begin to decrease with more than 1% Al.
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