Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9783103 | Materials Chemistry and Physics | 2005 | 5 Pages |
Abstract
To study localized corrosion mechanism of 2ÃÃÃ-series Al alloys containing θⲠand S precipitates, the electrochemical behaviors of a three-electrode coupling system of α(Al) substituting for alloy base, simulated bulk θⲠand S in 4.0% NaCl solution at pH 6.1 have been investigated. The potential of θⲠis positive to that of α(Al) and S, indicating that θⲠacts 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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Authors
Jin Feng Li, Zheng Ziqiao, Jiang Na, Tan Chengyu,