Influence of impurity content on corrosion behavior of Al-Zn-Mg-Cu alloys in a tropical marine atmospheric environment

The influence of impurity content on the corrosion behavior of Al-Zn-Mg-Cu alloys in a tropical marine atmospheric environment was systematically investigated. Combined with experimental measurements and theoretical calculations, it has been elaborated that the Volta potential difference is the main reason for the localized corrosion. The composition-property correlation has been established between the impurity contents, the type, size, and quantity of precipitates, and the corrosion behavior. The effects of impurity contents on the volume fraction of precipitates and corrosion parameters such as corrosion rate and average pit depth have been quantified, offering quantitative guidance to develop novel Al-Zn-Mg-Cu alloys.