Evolution of atmospheric corrosion of superplastic Zn-Al alloys exposed to an industrial environment

The microsturcture and atmospheric corrosion of superplastic Zn-Al alloys with various Al contents was investigated in an industrial environment. With increased Al content, the corrosion rates of the four samples initially increased and then decreased. ZA8 alloy showed the lowest corrosion resistance, whereas ZA16 alloy showed the highest resistance, and ZA12 showed a resistance similar to ZA16. The Al-rich phase was prone to preferential attack when the superplastic ZA alloy was exposed to an industrial environment. However, the corrosion rate of the alloy decreased with increased Al content. The continuous Al-rich phase effectively blocked the corrosion process