Atmospheric Corrosion of AZ31B Magnesium Alloy in the Antarctic Low-Temperature Environment

In this work, the outdoor corrosion behavior of AZ31B magnesium alloy in the Antarctic atmospheric environment was investigated. The surface corrosion state of the specimens exposed to the Antarctic atmosphere for 1 month and 24 months differ significantly. The corrosion rate after 1 month during the summer season was 19.82 g/m2·year and it decreased to 13.87 g/m2·year after two years’ exposure. Corrosion is initiated with pitting corrosion and then evolved to uniform corrosion with prolonging exposure time. The skyward surface exhibited a much severe corrosion than that of the groundward surface, attributed to the long-term existence of the adsorbed electrolyte layer. The corrosion products formed on the alloy exposed in Antarctica environment were MgCO3·3H2O, MgCO3·5H2O and Mg2CO3(OH)2·0.5H2O, with the MgCO3·3H2O as the dominant phase in the initial stage and the Mg2CO3(OH)2·0.5H2O as the dominant phase after long-term exposure.