Preparation and galvanic anodizing of a Mg–Li alloy

A Mg–10.02Li–3.86Zn–2.54Al–1.76Cu alloy was prepared and its corrosion-resistant coating was obtained in 25 g/L K2Cr2O7 + 25 g/L H2SO4 solution through galvanic anodizing. It is found that the alloy displays age-softening behavior. The micro-hardness of the quenched alloy increases with quenching temperature, which is caused by increased solution degree of Mg and Al in β phase. Its tensile strength increases as quenching temperature increases to 250 °C, due to the same reason. However, further temperature increase leads to the coarsening of β phase grains and a decrease in the tensile strength. The coating thickness increases with pH value decrease and operating temperature increase, while its corrosion resistance decreases. The results show that coatings obtained at room temperature with pH 4.5 and (or) pH 5.5 possess better corrosion resistance.