微量Ga对高压阳极铝箔腐蚀发孔性能的影响

Effect of trace Ga on pitting performance of high voltage anode aluminum foil

采用金相显微镜和扫描电镜观察腐蚀形貌,结合动电位极化曲线测试点蚀电位,研究微量Ga对高压阳极铝箔腐蚀发孔性能的影响。结果表明,含Ga铝箔经退火后,点蚀电位约为-0.85V,比退火态不含Ga铝箔的点蚀电位负移约80 mV;退火后Ga在铝箔表面发生富集,增强了铝箔在含氯离子溶液中的点蚀倾向。当Ga含量20×10-6时,铝箔腐蚀区面积比约98%,腐蚀区内蚀坑数量众多、分布均匀,扩面效果显著;Ga含量达到80×10-6时,虽然腐蚀区面积比高,但腐蚀区内局部区域形成粗大蚀坑,腐蚀均匀性有所降低。因此,添加适量Ga可显著改善铝箔在HCl-H2SO4溶液中的腐蚀发孔性能。

The influence of trace Ga on the pitting performance of aluminum foils was investigated.The distribution of pits and the morphological features of anode foils after pit etching were observed by metallographic microscopy and scanning electron microscopy,and the galvano-chemistry performance of foils was analyzed by using potentiodynamic polarization.The results indicate that heat treatment of Ga-contained foils at 813 K for 1 h makes the pitting potential shift negatively to about -0.85 V,which is 80 mV lower than that of the annealed Ga-free foil,and Ga segregate to the surface.As a results,the susceptibility to pitting corrosion of foils in Cl--contained solution is promoted.After pit etching,high ratio of corrosion area about 98% and high density of relatively uniformly distributed pits are obtained for the foil with about 20×10-6 Ga,while some huge pits form and the homogeneity of pitting corrosion decreases when the content of Ga reaches 80×10-6.Consequently,Ga,as an eco-friendly element,can be applied with a proper quantity to improve the homogeneous pitting ability of high voltage anode aluminum foil.