低温青藏高原土壤中镁合金阳极的电化学性能

为评价低温土壤对镁合金阳极电化学性能的影响,通过极化曲线、交流阻抗和电流效率实验方法,研究了4种镁合金阳极在-4℃和4℃的模拟低温青藏高原土壤中的电化学性能.研究表明:镁合金中加入Mn、Al和Zn元素可与杂质元素形成阴极作用较弱的金属间化合物,降低了镁合金的自溶解倾向,提高了电流效率;镁合金阳极在低温青藏高原土壤中呈活性溶解状态,溶解活性和反应活性由强到弱顺序为MGAZ63B镁合金、MGAZ31B镁合金、MGM1C镁合金和高纯镁;4种镁合金阳极中MGAZ63B的电流效率最高,-4℃和4℃时分别为54.39%和61.77%;4℃土壤中氧的扩散速率比-4℃时高,故镁合金阳极在青藏高原土壤中4℃时溶解活性和电流效率均优于-4℃时.

Electrochemical performance of magnesium anodes in Qinghai-Tibetan plateau soil at low temperature

In order to investigate the effect of low temperature soil on magnesium anode, the electrochemical performance of four magnesium alloy anodes in simulated Qinghai-Tibetan plateau soil at low temperatureof -4 ℃ and 4 ℃ was studied by polarization curves, electrochemical impedance and current efficiency tests. The results showed that addition of Mn, Al and Zn elements could decrease the natural dissolution tendency of magnesium alloy, and increase the current efficiency through the formation of an intermetallic compound with weak cathodic effect between Mn, Al, Zn and impurity elements. Magnesium alloy anodes presented active dissolution state in low temperature Qinghai-Tibetan plateau soil. The sequence of dissolution activation and reaction activation from high to low was MGAZ63B, MGAZ31B, MGMIC and pure magnesium. Among these four anodes, current efficiency of MGAZ63B was the highest, and the values were 54.39%and 61.77% at -4 ℃ and 4 ℃ respectively. For diffusion rate of oxygen at 4 ℃ soil was higher than that of at -4 ℃, the dissolution activation and current efficiency of magnesium alloy anodes in Qinghai-Tibetan plateau soil at 4 ℃ were superior to that of at -4 ℃.