铝合金牺牲阳极的镀锌处理及其电化学性能

摘要

The surface of A1 alloy-based sacrificial anodes were galvanized to different thicknesses, and the electrochemical performance of the anodes were analyzed by polarization testing, EIS and self-discharge method. The polarization curves showed that the corrosion potential of galvanized specimens shifted positively with the increase of zinc coating thickness. The results of EIS showed that the electrochemical activity of the samples increased. The results of self-discharge tests showed that there was little influence of Zn layer on the couple current as time changed, but the change of protection couple current tended to more smooth for anodes with certain thickness of Zn layer. The change of cathodic protection potential with time decreased fast firstly, then tended to be slow and stable at last. The thicker the Zn layer, the more negative the shift degree of cathodic potential.%在铝合金牺牲阳极表面镀覆了不同厚度的锌层，对镀锌阳极试样进行了极化曲线和电化学阻抗测试，并采用自放电法分析了镀锌阳极试样的电化学性能。极化曲线结果表明，镀锌阳极试样的腐蚀电位随锌层厚度增加逐渐正移；电化学阻抗谱表明，镀锌试样电化学活性增加；自放电试验结果表明，镀锌层对电偶电流随时间的变化趋势影响不大，但一定厚度的锌层能使保护电流密度变化更趋平稳；阴极保护电位随时间变化总的趋势是先快速下降，而后趋于缓慢下降至稳定，镀锌层越厚阴极电位负移程度越大。