Article ID Journal Published Year Pages File Type
9783103 Materials Chemistry and Physics 2005 5 Pages PDF
Abstract
To study localized corrosion mechanism of 2×××-series Al alloys containing θ′ and S precipitates, the electrochemical behaviors of a three-electrode coupling system of α(Al) substituting for alloy base, simulated bulk θ′ and S in 4.0% NaCl solution at pH 6.1 have been investigated. The potential of θ′ is positive to that of α(Al) and S, indicating that θ′ acts as cathodic zone in the alloy. S is main anodic phase, and the anodic dissolution of S will cause its pitting corrosion. However, during the corrosion of S, Mg is preferentially dissolved, resulting in noble Cu-rich remnants, which makes its potential move to positive direction with immersion time. As a result, corroded S becomes cathodic to α(Al), leading to anodic dissolution of α(Al) and pitting corrosion of the alloy base at adjacent periphery of S precipitate.
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Physical Sciences and Engineering Materials Science Electronic, Optical and Magnetic Materials
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