The effect of temperature on the NaCl-induced atmospheric corrosion of the Mg–Al alloy AM50 has been investigated in the laboratory. The corroded samples were analyzed gravimetrically and by SEM, EDX, XRD, and FTIR. The atmospheric corrosion of 99.97% Mg was also studied for reference. While the NaCl-induced atmospheric corrosion of AM50 is strongly reduced with decreasing temperature, 99.97% Mg does not exhibit such a trend. The temperature dependence of the atmospheric corrosion of alloy AM50 is attributed to the aluminum content in the alloy. Several crystalline magnesium hydroxy carbonates formed at 4 and 22°C but were absent at −4°C

The NaCl-induced atmospheric corrosion of the MgAl alloy AM50 has been investigated using 99.97% Mg as reference. Polished samples were exposed up to 672 h in 95.0% RH air with 400 ppm or 0 ppm CO₂ at 22.00°C. Samples were analyzed gravimetrically and by SEM/EDX, XRD and XPS. CO₂ inhibited atmospheric corrosion with alloy AM50 corroding 6–7 times faster in the absence of CO₂. Brucite and meixnerite (Mg₆Al₂(OH)₁₈ × 4.5H₂O) formed in the absence of CO₂. In the presence of CO₂ and NaCl three magnesium-hydroxy-carbonates, giorgiosite, hydromagnesite and Mg₅(CO₃)₄(OH)₂ × 8H₂O formed. The influence of CO₂ on the electrochemical corrosion process is discussed.