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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 corrosion mechanism of superplastic Zn-Al alloy in acid rain environment was systematically studied by comparing the corrosion behavior of superplastic Zn-Al alloys with different Al contents in simulated acid rain solution. The results show that the corrosion behavior of Zn-Al alloy in simulated acid rain solution is related to its microstructure. The Al-rich phase is preferentially eroded. With the increase of Al content in the alloy, the Al-rich phase increases and the corrosion rate of the alloy decreases. This is because the discontinuous Al-rich phase is distributed on the grain boundaries of the ZA4 alloy and the ZA8 alloy, the corrosion products are not dense, the corrosion pits gradually develop in the depth direction, and the corrosion rate is relatively high. The ZA12 alloy and ZA16 alloy exist continuous distribution of Al rich phase, the surface of the formation of dense corrosion product film, can effectively hinder the reaction.