| The corrosion characteristics of AZ91 Mg alloy were studied in various anion-containing solutions. Through weight loss test, changes of corrosion potential under open circuit condition, changes of corrosion current density under potentiostatic condition and optical microscopy, effects of various anions on corrosion behaviours of AZ91 Mg alloy were investgated. It was found that chloride ion had two different effects on corrosion behaviours of AZ91 Mg alloy. When only chloride ions exist in water solution without any other anions, those make pitting corrosion, accelerate more rapidly. But when small amount of chloride ions exist with sulfate or nitrate ions, those make pitting corrosion occur slowly rather than in only sulfate or nitrate ions containing solution. These results were interpreted as competitive adsorption between chloride ion and sulfate or nitrate ion. |
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