Al－Zn－In－Si合金在NaCl溶液中的小孔腐蚀行为

研究了溶液中Ｃｌ－浓度和温度对Ａｌ－Ｚｎ－Ｉｎ－Ｓｉ和Ａｌ－Ｚｎ－Ｉｎ－Ｓｉ－Ｍｇ合金小孔腐蚀行为的影响，并利用电子探针对蚀孔进行形貌观察和线扫描分析。结果表明：Ｃｌ－浓度和温度变化对合金的阳极极化行为和孔蚀性能有较大影响；从孔蚀行为看，作为牺牲阳极，经加镁改性的合金较未加镁合金更佳。蚀孔出现在富Ｉｎ、Ｓｉ点周围，Ｃｌ－浓度较低时蚀孔底部的富Ｉｎ、Ｓｉ＂岛状物＂在浓度较高时逐渐溶解脱落，Ｉｎ、Ｓｉ在孔边缘富集。

PITTING CORROSION BEHAVIOR OF Al-Zn-In-SI ALLOYS IN NaCl SOLUTIONS

he pitting potentials Eb of Al-Zn-In-Si and Al-Zn-In-Si-Mg alloys were measured in NaCl solutions.Influence of chloride ion concentration and temperature on pitting corrosion susceptibility was examined.Results showed that with the increase in Cl- concentration and temperature, the Eb decreased and pitting corrosion became more severe. From the standpiont of pitting corrosion, Al-Zn-In-Si-Mg alloy used for sacrificial anode was superior to Al-Zn-In-Si alloy. The corrosion morphology and EPA line scan analysis showed that the content of indium and silicon at pit bottom was much higher than the average content in alloy and that pitting corrosion mainly occurred around in and St-rich "islands".