Corrosion Resistance of Mg Alloy with High Zn Concentration Including Impurity Cu

Abstract:

Mg alloys are very attractive materials for transportation industry due to their toughness and lightness. Recycling Mg alloys is desired for energy saving that otherwise would be required to produce its primary metal. However, secondary produced Mg tends to contain a few impurity elements that deteriorate its corrosion resistance. For example, contamination of Mg alloy by Cu induces second phase of Mg₂Cu and it works as strong cathode, resulting in the corrosion rate rapidly increasing. It was previously reported that the corrosion resistance of Mg with impurity Cu was remarkably improved by addition of alloying element Zn. Addition of Zn into Mg formed MgZn₂ phase and incorporated Cu into MgZn₂ phase instead of Mg₂Cu formation. In this way, since Zn serves to improve the corrosion resistance of Mg, Mg alloy with high Zn concentration may form a lot of MgZn₂ and may have better corrosion resistance even with high Cu concentration. In this work, the corrosion behavior of Mg-6mass%-1mass%Al (ZA61) with different Cu content up to 1mass% was investigated. As a result, ZA61-1.0Cu had much lower corrosion rate compared to Mg-0.2%Cu and the corrosion rate was almost the same as that of pure Mg.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 592-597
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.592
• Online since: January 2021
• Authors: Masato Ikoma*, Taiki Morishige, Tetsuo Kikuchi, Ryuichi Yoshida, Toshihide Takenaka
• Keywords: Corrosion, Impurity Element, Mg Alloy, Microstructure, Recycle

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