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采用金相显微镜、X射线衍射及扫描电镜研究Zn含量对Mg-Al-Pb-Zn系镁阳极材料显微组织、相结构及表面形貌的影响;通过恒电流法、动电位极化法、排水集气法等研究该镁合金的腐蚀行为和电化学性能。结果表明:随着Zn质量的增加,合金晶粒愈加细小,形成细小的等轴晶;合金主要由α-Mg基体及长棒状的β-Mg17Al12相、颗粒状的MgZn相和Mg2Pb相组成;Zn的加入可以提高镁合金放电电压和电流效率,降低析氢率。由于镁合金的“负差数效应”使析氢率随电流密度的增大而增大,当电流密度为10 mA/cm2时,电流效率最高,可达91%;腐蚀产物主要成分为Mg(OH)2、Al2O3、PbO2及MgAl2O4,且疏松、易脱落,使得镁合金阳极的工作电极电位负而且稳定,可促进电池反应深入进行。
The effects of Zn content on the microstructure, phase structure and surface morphology of Mg-Al-Pb-Zn magnesium anode materials were investigated by metallographic microscope, X-ray diffraction and scanning electron microscopy. By galvanostatic method, Drainage and gas collection method to study the corrosion behavior of the magnesium alloy and electrochemical properties. The results show that as the mass of Zn increases, the grain size of the alloy becomes smaller and fine equiaxed grains are formed. The alloy is mainly composed of α-Mg matrix, long rod-shaped β-Mg17Al12 phase, granular MgZn phase and Mg2Pb phase. The addition of magnesium can improve the discharge voltage and current efficiency, reduce the hydrogen evolution rate. Due to the “negative difference effect” of magnesium alloy, the hydrogen evolution rate increases with the increase of current density. When the current density is 10 mA / cm2, the current efficiency is the highest, up to 91%. The main components of corrosion products are Mg (OH) 2, Al2O3, PbO2 and MgAl2O4, and loose, easy to fall off, making the magnesium alloy anode working electrode potential negative and stable, can promote the battery reaction in-depth.