铝含量对超塑性锌铝合金腐蚀行为的影响

INFLUENCE OF ALUMINIUM CONTENT ON CORROSION BEHAVIOR OF SUPERPLASTIC Zn-Al ALLOYS

通过比较不同Al含量的超塑性Zn-Al合金在模拟酸雨溶液中的腐蚀行为,系统研究了超塑性Zn-Al合金在酸雨环境中的腐蚀机理。结果表明,Zn-Al合金在模拟酸雨溶液中发生的腐蚀行为与其显微组织有关。富Al相优先腐蚀,随着合金中Al含量的提高富Al相增多,合金的腐蚀速率反而下降。这是因为ZA4合金与ZA8合金晶界上分布有不连续的富Al相,腐蚀产物不致密,腐蚀坑逐渐向纵深方向发展,腐蚀速率相对较高。而ZA12合金与ZA16合金存在连续分布的富Al相,其表面形成致密的腐蚀产物膜,能有效阻碍反应的进行。

The influence of aluminium content on the corrosion behavior of superplastic Zn-Al alloys immersed in simulated acid rain was investigated. The results showed that, the corrosion behavior of the Zn-Al alloy in simulated acid rain solution was related to the microstructure of the alloy. Al-rich phase was prone to preferential attack, but the corrosion rate of the alloy was decreased with the aluminum content of the alloys increases. There was a discontinuous Al-rich phase distributed on the grain boundaries of ZA4 alloy and ZA8 alloy, the corrosion products were loose and the corrosion pits were deeper, that resulted in a relatively high corrosion rate, whereas the corrosion reaction can be effectively blocked by the continuous distribution of Al-rich phase of ZAl2 alloy and ZA16 alloy.