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用模拟湿热腐蚀试验方法在工业纯铝、ＺＬ１０２和ＺＬ１０９合金表面诱发腐蚀，用ＳＥＭ、ＥＤＳ和ＸＲＤ等实验手段观察和分析了铸铝合金中第二相和腐蚀产物的微观形貌及化学成分，研究了第二相与表面缺陷对铸铝合金大气腐蚀发生机制的影响．结果表明，在吸附了水分和侵蚀性Ｃｌ－的微观孔隙周围，由Ａｌ６Ｃｕ３Ｓｉ相粒子和铝基体构成的腐蚀微电池发生电化学反应，电位较负的Ａｌ首先发生溶解，导致了局部点状腐蚀；腐蚀产物中除了存在少量共晶硅、氧化铝外，主要由铝的不溶性氢氧化物构成．在０．５ｍｏｌ／ＬＮａＣｌ水溶液中的电化学测试结果表明，由于富铜Ａｌ６Ｃｕ３Ｓｉ第二相粒子的存在，在含侵蚀性Ｃｌ－的介质中，ＺＬ１０２、ＺＬ１０９合金比纯铝具有更强的腐蚀倾向．
The simulated wet-hot corrosion test was used to induce corrosion on the industrial pure aluminum, ZL102 and ZL109 alloy surfaces. The microstructure and chemical composition of the second phase and the corrosion products in the cast aluminum alloy were observed and analyzed by means of SEM, EDS and XRD. The effects of second phase and surface defects on the mechanism of atmospheric corrosion of cast aluminum alloy were studied. The results show that the electrochemical corrosion of the micro-cells consisting of Al6Cu3Si phase particles and the aluminum matrix occurs around the microscopic pore with adsorbed moisture and aggressive Cl-. The more negatively charged Al first dissolves, resulting in localized pitting corrosion. Except for a small amount of eutectic silicon and aluminum oxide, the corrosion products are mainly composed of insoluble hydroxides of aluminum. The results of electrochemical tests in 0.5 mol / L NaCl aqueous solution show that the ZL102 and ZL109 alloys have a stronger corrosion tendency than pure aluminum in the medium containing aggressive Cl- due to the presence of the second phase particles of Cu-rich Al6Cu3Si.