Effects of cadmium alloying on the corrosion and mechanical properties of magnesium

The effect of Cd on the corrosion-resistant behavior and mechanical performance of Mg using gas collection, electrochemical measurements and tensile stress tests has been investigated. The experimental results showed that in the cathodic polarized region, hydrogen evolution and magnesium hydride formation were significantly reduced, whereas in the anodic polarized region, the negative difference effect was restrained and the anodic dissolution slightly enhanced when Cd (2.04 wt.%) is alloyed to Mg. The sum effect of the cathodic and anodic reactions results in an improvement of the corrosion resistant behavior in Mg-Cd alloy. Furthermore, the addition of Cd has been found to reduce the susceptibility to stress corrosion cracking. The mechanisms of these improved properties has been clarified by considering the formation of a stable Mg ν+- Cd δ- galvanic couple in the Mg-Cd alloy that can be applied in the interpretation of the corrosion behavior of other Mg alloys. © 2012 by ESG.