Mn含量对Mg-Mn阳极显微组织和电化学性能的影响

Effects of Mn Content on Microstructure and Electro-chemical Properties of Mg-Mn Sacrificial Anodes

采用高纯镁为原料制备高效Mg-Mn牺牲阳极,探讨了Mn含量分别为0.3%、0.6%、0.8%、1.0%时,对Mg-Mn牺牲阳极显微组织和电化学性能的影响。结果表明,Mn能够有效降低镁熔体中Fe的含量,提高镁阳极的电流效率,但过多的Mn能够和Si、C、O形成相对于α-Mg基体的少量阴极相,加重镁阳极的自腐蚀,使镁阳极的电流效率降低,不同Mn含量的Mg-Mn阳极基体组织均为α-Mg固溶体,Mn含量较低时组织为粗大的柱状晶,增大Mn的含量组织为等轴晶,继续增大Mn含量晶粒细化不明显。

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.