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以2198铝-锂合金为研究对象,在硫酸-己二酸电解质溶液中进行阳极氧化,并对氧化后的试样进行沸水封闭处理。采用场发射扫描电子显微镜(FE-SEM)和原子力显微镜(AFM)对氧化膜的表面和截面的形貌进行观察。通过电化学阻抗谱(EIS)、塔菲尔(Tafel)曲线和浸泡实验来分析阳极氧化膜的耐蚀性能。结果表明铝-锂合金在阳极氧化过程中由于含铜合金相的影响,形成的氧化膜孔洞不完整出现连通现象;电化学测试结果表明封闭之后的氧化膜的耐蚀性明显提高,并且随着浸泡时间的延长拟合等效电路发生改变,同时多孔层和阻挡层的阻抗值在降低,说明在浸泡的过程中氧化膜的结构发生改变,耐蚀性降低。
The 2198 aluminum - lithium alloy was used as the research object, anodized in sulfuric acid - adipic acid electrolyte solution, and the oxidized samples were closed by boiling water. The morphology of the surface and cross-section of the oxide film was observed by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The corrosion resistance of the anodized film was analyzed by electrochemical impedance spectroscopy (EIS), Tafel curve and immersion test. The results show that due to the influence of the copper-containing alloy phase during the anodization, the interconnected pores of the oxide film are incompletely formed. The results of electrochemical tests show that the corrosion resistance of the oxide film after the encapsulation is obviously improved, The change of the equivalent circuit of the fitting of the immersion time is changed, while the resistance value of the porous layer and the barrier layer is decreased, indicating that the structure of the oxide film changes during immersion and the corrosion resistance decreases.