合金元素对Mg-Hg-Ga阳极材料电化学行为的影响(英文)

Influence of Alloying Elements on Electrochemical Behavior of Mg-Hg-Ga Anodes

用恒电流法,析氢法和交流阻抗法等方法测试了合金元素Hg和Ga对镁阳极电化学腐蚀行为的影响,并用扫描电镜和X射线衍射法分析了合金元素Hg和Ga对镁阳极的显微组织和相结构的影响。结果表明:铸态的Mg-4.8%Hg-8.8Ga合金晶界析出Mg5Ga2和Mg21Ga5Hg3相,铸态的Mg-8.8%Hg-8%Ga和Mg-7.2%Hg-8%Ga合金晶界析出Mg21Ga5Hg3相,铸态的Mg-7.2%Hg-2.6%Ga合金析出Mg3Hg和Mg21Ga5Hg3相。各合金析氢速率从小到大依次为:Mg-7.2%Hg-2.6%Ga合金,Mg-4.8%Hg-8%Ga合金,Mg-7.2%Hg-8%Ga合金和Mg-8.8%Hg-8%Ga合金。最小的析氢速率为1.75ml/(cm2.min)。各合金电化学活性从大到小依次为:Mg-8.8%Hg-8%Ga合金,Mg-7.2%Hg-8%Ga合金,Mg-4.8%Hg-8%Ga合金和Mg-7.2%Hg-2.6%Ga合金。在200 mA/cm2恒电流测试中最负的稳定电位-1.932 V出现在Mg-8.8%Hg-8%Ga合金中。

The effects of alloying elements Hg and Ga on the electrochemical corrosion behavior of Mg anodes were studied by galvanostatic tests,hydrogen evolution tests and electrochemical impedance spectra（EIS） measurements under different polarization conditions.Scanning electron microscopy（SEM） and X-ray diffractometry（XRD） were employed to detect the microstructure and phase relationship of the above alloys.Attention was paid to the combined effect of Hg and Ga on electrochemical properties and microstructures.The results show that Mg5Ga2 and Mg21Ga5Hg3 phases precipitated along the grain boundaries in cast Mg-4.8%Hg-8%Ga alloy.Mg21Ga5Hg3 phases precipitated in cast Mg-8.8%Hg-8%Ga and Mg-7.2%Hg-8%Ga alloys.Mg3Hg and Mg21Ga5Hg3 phases precipitated in cast Mg-7.2%Hg-2.6%Ga alloy.The sequential order of the hydrogen evolution corrosion rates from small to large is Mg-7.2%Hg-2.6%Ga alloy,Mg-4.8%Hg-8%Ga alloy,Mg-7.2%Hg-8%Ga alloy,and Mg-8.8%Hg-8%Ga alloy.The smallest hydrogen evolution corrosion rate is 1.75 ml/（cm2·min）.The sequential order of the electrochemical activity from large to small is Mg-8.8%Hg-8%Ga alloy,Mg-7.2%Hg-8%Ga alloy,Mg-4.8%Hg-8%Ga alloy,and Mg-7.2%Hg-2.6%Ga alloy.The most negative stable potential of-1.932 V occurs in the Mg-8.8%Hg-8%Ga alloy in the galvanostatic test with 200 mA/cm2 current density.