Effects of different Mn contents

such as 0.3%

0.6%

0.8% and 1.0%

on the microstructure and electro-chemical properties of the Mg-Mn sacrificial anodes were investigated based on the Mg-Mn anodes with sound electro-chemical properties which were prepared by the highly purified raw magnesium. The results reveal that Mn can effectively reduce Fe content in the magnesium melts and improve the current efficiency of magnesium anodes

however

excessive Mn will decrease the current efficiency of the magnesium anodes due to forming a little secondary phase with Si

C

O as the cathode to promote the self-corrosion of the anodes. The matrix microstructure of the Mg-Mn alloy with different Mn contents is composed of α-Mg solid solution phase which exhibits coarse columnar grain with lower Mn content while it becomes equiaxed grain with increasing in Mn content. However

it shows slight change with excessive Mn content.