Effect of Homogenization on Microstructure and Properties of Mg-6Al-5Pb-0.6Ce Magnesium Anode

Mg-6Al-5Pb-0.6Ce alloy anode was prepared by melting and casting. The effect of homogenization on microstructure of this alloy was investegated by XRD and SEM. Its corrosion and electrochemical behavior before and after homogenization of the alloy were studied by potentiodynamic plorization and galvanostatic discharge. The results indicated that the island-like β-Mg17Al12 phase was dissolved into the magnesium matrix and the composition segregation almost disappeared after homogenizing at 400 ℃ for 24 h. Compared with the as-cast alloy, the disappearance of the effective cathodic phase (β-Mg17Al12) in the homogenized alloy led to a decrease of galvanic corrosion and an improvement of corrosion resistance. Moreover, the discharge potential of Mg-6Al-5Pb-0.6Ce magnesium anode was shifted from -1.756 V (SCE) to -1.726 V (SCE) after homogenization, resulting in a weakening of the discharge activity. However, its anode utilization efficiency reached 79.8%, which was 5.1% higher than that of the as-cast alloy.