Comparative study on corrosion behaviors of Mg-Al-Zn alloys
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CitationCANDAN, S., & CANDAN, E. (2018). Comparative study on corrosion behaviors of mg-al-zn alloys. Transactions of Nonferrous Metals Society of China (English Edition), 28(4), 642-650. doi:10.1016/S1003-6326(18)64696-5
A comparative study on corrosion behaviors of various Mg−Al−Zn alloys (AZ21, AZ41, AZ61 and AZ91 series, cast under same cooling conditions and controlled alloying composition) was carried out. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used for microstructural examinations. The corrosion behaviors were evaluated by immersion tests and potentiodynamic polarization measurements in 3.5% NaCl solution. The results showed that the influence of Al addition on corrosion resistance was more pronounced up to 4% (i.e. AZ41) above which its influence was at less extent. The deterioration of the corrosion resistance of the alloys, at higher Al contents, was attributed to the amount and morphology of β-Mg17Al12 intermetallics and the interruption of continuity of the oxide film on the surface of the alloys owing to coarsened β intermetallics.