通过测定Al-Zn-Sn-Ga阳极在3.5％ NaCl(质量分数)溶液中浸泡不同时间的电化学阻抗谱(EIS),研究该阳极的腐蚀发展过程和腐蚀特征.结果显示:当合金刚被浸入3.5％ NaC1溶液时,EIS谱为反应电阻很大的容抗弧,表明此时合金处于钝化态；随着浸泡时间的延长,EIS谱中高频段的容抗弧明显减小且低频段出现感抗弧,合金进入点蚀期;继续延长浸泡时间,EIS谱中除高频段的容抗弧和中、低频段感抗弧外,在低频段出现另一容抗弧,合金处于点蚀扩展期；随着浸泡时间的继续增加,低频段感抗弧消失,EIS谱由两个容抗弧组成,合金达到均匀腐蚀期.因此,合金的腐蚀由钝化态开始,经点蚀期和点蚀扩展期,达到均匀腐蚀期.%The corrosion extension process and characteristics of Al-Zn-Sn-Ga anode in 3.5% NaCl (mass fraction) solution for different immersion times were investigated by electrochemical impedance spectroscopy (EIS). The results show that the EIS spectrum at the beginning of immersion consists of a large capacitive arc, indicating the passivation. With the increase of immersion time, the capacitive arc at high frequency is significantly reduced, and an inductive loop at low frequency appears, implying the pitting. With extending the immersion time, another capacitive arc at low frequency appears in EIS spectra, suggesting the pitting growth. With the further prolonging of immersion time, the inductive arc at low frequency disappears, and the EIS spectrum is composed of two capacitive arcs, hinting the uniform corrosion. So, the corrosion of Al-Zn-Sn-Ga alloy initiates from the passive film, and then the pitting, followed by the pitting growth, and finally the uniform corrosion.
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