An AM60 magnesium alloy was exposed to immersion and cyclical salt spray environments to characterize its corrosion rate. General corrosion, pitting corrosion, and intergranular corrosion rates were quantified at various intervals for as-cast and polished samples. General corrosion and intergranular corrosion occurred at higher rates on the immersion surfaces as compared to the salt spray surfaces. Pit nucleation occurred at the highest rate on the immersed polished surfaces followed by the immersed as-cast surface. Pit growth and coalescence occurred at the highest rate on the salt spray as-cast surface followed by the immersed as-cast surface. The differences in corrosion characteristics between the polished surfaces and the as-cast surfaces were attributed to the lack of the as-cast skin on the polished surfaces, which normally acts to inhibit corrosion. The differences in corrosion characteristics between the environments was attributed to the continuous presence of water and chloride ions that allowed for higher general corrosion, intergranular corrosion, and pit nucleation as a result of the continuous surface reactions, but inhibited pit growth and pit coalescence because of the removal of surrounding magnesium during general corrosion.

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