The Corrosion Resistance of the Mg-Al-Ca-Sr Sand Casting Magnesium Alloys

Abstract:

In this paper, the corrosion resistance of two sand-casting creep resistant magnesium alloys Mg-9Al-1.5Ca-0.3Sr and Mg-9Al-2.2Ca-0.8Sr in the salt environment has been investigated. Specimens of each alloy has been immersed in 3.5% NaCl solution at room temperature and successively taken out after 1, 2, 4, 5 and 9 days. After immersion test, the microstructure and the appearances of the corroded structure were examined. The corrosion rates of both investigated alloys increased lineally with increasing the exposure time in both solutions. Mg-9Al-1.5Ca-0.3Sr alloy exhibits the higher corrosion rate during the immersion test than Mg-9Al-2.2Ca-0.8Sr. The corrosion layer of both alloys consists of MgO, MgOH and phases containing Cl, Na, Al and Ca. The increase of Ca content in the Mg-9Al-2.2Ca-0.8Sr alloy improved the corrosion resistance due to the formation of the reticular (Mg,Al)₂Ca phase, which acted as an effective barrier against corrosion.

• Periodical: Defect and Diffusion Forum (Volumes 326-328)
• Pages: 255-260
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.326-328.255
• Online since: April 2012
• Authors: Andrzej Kiełbus, Tomasz Rzychoń, Joanna Michalska, Michal Stopyra
• Keywords: Corrosion, Mg-Al-Ca-Sr Magnesium Alloys, Microstructure, Sand Casting

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