Comparison of corrosion pitting under immersion and salt-spray environments on an as-cast AE44 magnesium alloy

The corrosion mechanisms of pitting, intergranular corrosion, and general corrosion were examined on an AE44 magnesium alloy subjected to immersion and salt-spray environments. The two environments show similar trends with respect to weight loss and thickness loss, although the immersion environment induces greater amounts of weight loss of magnesium. With respect to the corrosion mechanisms, the two environments show definitive trends, owing to the continuous presence of water in the immersion environment allowing more and larger pits to form as compared to the salt-spray environment. The immersion environment was more deleterious than the salt-spray environment for magnesium.

Research highlights
► AE44 corrosion mechanisms in two environments were studied
► General corrosion and pit numbers were higher in the immersion environment
► Pit characteristics, such as area and volume, were larger on the salt-spray surfaces
► The continuous presence of water affected the general corrosion and pit formation
► The build-up of chloride ions affected pit growth on the salt-spray surfaces