Corrosion Behaviour of AZ63 Magnesium Alloy in Natural Seawater and 3.5 wt.% NaCl Aqueous Solution

In this study, the corrosion behaviour of AZ63 magnesium alloy was investigated in natural seawater and neutral 3.5 wt.% NaCl aqueous solution. The electrochemical processes were studied using potentiodynamic polarization. The composition and morphology of the alloys and corrosion products formed were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results highlighted the differences between the corrosion mechanisms of AZ63 magnesium alloy in natural seawater and that in 3.5 wt.% NaCl solution. The corrosion products formed in the seawater primarily consisted of CaCO3 and Mg(OH)(2), while the corrosion products formed in the 3.5 wt.% NaCl solution primarily consisted of Mg(OH)(2) and Mg-2(OH)(3)Cl center dot 4H(2)O. The results of hydrogen evolution, weight loss and potentiodynamic polarization tests showed that the AZ63 magnesium alloy samples had better corrosion resistance in natural seawater than in 3.5 wt.% NaCl aqueous solution.