Mg-7Y-2.5Zn-2Si/Al镁合金的电化学腐蚀行为研究

Study on the Electrochemical Corrosion Behavior of Mg-7Y-2.5Zn-2Si/Al Magnesium Alloy

镁合金具有较高的比强度、比刚度等优点,广泛应用于各个领域,如汽车、飞机、医用材料等,但镁合金耐蚀性很差,为了更好地了解镁合金耐电化学腐蚀性能,本文将镁合金Mg-7Y-2.5Zn-2Al和Mg-7Y-2.5Zn-2Si试样分别进行电化学腐蚀实验,在介质为3.5%NaCl水溶液和SBF溶液(模拟体液),腐蚀后用动电位极化法绘制出动电位极化曲线,用扫描电镜(SEM)观察镁合金表面形貌,并采用维氏硬度仪分析其对镁合金硬度的影响。镁合金的电化学腐蚀行为实验结果显示,含Si镁合金在3.5%NaCl溶液和SBF溶液中耐电化学腐蚀性能好于含Al镁合金。

Magnesium alloy with high specific strength and stiffness is widely applied in various fields, such as cars, aircrafts, medical materials, etc. However, magnesium alloy has the poor corrosion resistance. In this paper, in order to improve the electro-chemical corrosion resistance of magnesium alloy, the electrochemical corrosion properties of Mg-7Y-2.5Zn-2Al magnesium alloy and Mg-7Y-2.5Zn-2Si magnesium alloy were studied in 3.5% NaCl and SBF solution. After the electrochemical corrosion test, the dynamical potential polarization curve was drawn by the dynamical potential polarization method;vickers hardness test was conducted for two samples, and surface morphology was observed by scanning electron microscopy（SEM）. The electrochemical experimental results show that the Si-containing magnesium alloy has better corrosion resistance than the Al-containing magnesium alloy. The surface hardness of magnesium alloy is almost no change before and after electrochemical corrosion test.