Influence of heat treatment on electrochemical behavior of Mg anode materials

The effects of heat treatment on the electrochemical corrosion behavior of Mg-2.2%Hg-Ga(mass fraction) anode materials were investigated by the polarization curves and galvanostatic tests. The scanning electron micrographs of precipitates of the secondary phase after aging treatment and the corroded surface of the specimens after galvanostatic test were observed. The phase of the alloy in different states was determined by X-ray diffraction and energy spectrum analysis. The results show that the Mg5Ga2 phase precipitates homogeneously along the grain boundary and within the grain in the Mg-2.2%Hg-Ga alloys aging at 473 K for 96 h. The electrochemical activity of the alloys is in the order from small to big: super-saturated solid solution, the specimens aged at 473 K for 2 h, the specimens aged at 473 K for 96 h, the as-east specimens. The corrosion resistances of the alloys follow the opposite order. The corrosion of the aging Mg-Hg-Ga alloy is mainly generous attack and pitting attack.