Mg和RE合金化对Al-Zn-Bi合金阳极组织和电化学性能的影响

Influence of Mg and RE on microstructure and electrochemical properties of Al-Zn-Bi alloy anode

针对Al-Zn-Bi合金,分别单独及复合添加Mg、RE元素进行微合金化,利用金相、扫描电镜及X射线能谱等分析了该合金添加不同元素前后的微观组织特征;采用恒电流法测定了该系列合金在人造海水中的开路电位、工作电位和电流效率,利用极化曲线和电化学阻抗谱,分析了微合金化对Al-Zn-Bi阳极材料电化学性能的影响。结果表明:单独添加Mg、RE可以细化晶粒、改善偏析相的组成和分布,将电流效率提高15.93%和4.12%;二者复合添加虽电流效率稍有降低,但可促使基体均匀溶解,减小腐蚀电流密度,从而有效提高其综合性能。

Influence of Mg and RE elements on microstructure of Al-Zn-Bi alloy anodes was investigated by means of metallographic microscopy,scanning electron microscopy and X-ray energy dispersive analysis.The open circuit potential,working potential and current efficiency of the alloys in artificial seawater were tested by constant current method.Effects of Mg or/and RE alloying elements on electrochemical properties of Al-Zn-Bi alloy anodes in 3.5% NaCl solution were studied by polarization curves and electrochemical impedance spectra.The results show that grain size of the alloys becomes smaller and the composition and distribution of segregation phases are improved,consequently,the current efficiency can be raised by 15.93% and 4.12% through adding Mg and RE in the Al-Zn-Bi alloy respectively.Although the current efficiency of the alloy decreases slightly when Mg and RE are added together,the corrosion current density is reduced and the corrosion of the matrix becomes more homogeneous,which improves performance of the alloy ultimately.