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采用金相显微镜、X射线衍射(XRD)、扫描电镜(SEM)、结合能谱( EDS )研究了Sn对镁阳极材料显微组织、相结构、表面形貌及成分分布的影响;并通过恒电流法、动电位极化法、排水集气法等研究了该镁合金的腐蚀行为和电性能。结果表明:合金元素Sn、Pb的加入可以抑制棒状β-Mg17Al12相沿晶界析出,合金晶粒尺寸均匀,随着Sn含量的增大,颗粒相Mg2Sn增多;均匀化处理使大部分β-Mg17Al12相溶解,而残留Mg2Sn和Mg2Pb未溶相;Sn的加入可以提高镁合金自腐蚀电位,降低析氢率,当Sn含量为2wt%时,镁合金阳极的放电电压和电流效率最大。由于镁合金的“负差数效应”使得析氢率随电流密度的增大而增大,当电流密度为10mA/cm2时,电流效率最高,可达88%;腐蚀产物主要成分为Mg(OH)2、SnO2及MgSnO3,且疏松,易脱落,使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 Sn on the microstructure, phase structure, surface morphology and composition distribution of magnesium anode materials were investigated by metallographic microscope, X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) Current method, potentiodynamic polarization method, drainage gas collection method to study the corrosion behavior and electrical properties of the magnesium alloy. The results show that the addition of alloying elements Sn and Pb can restrain the precipitation of β-Mg17Al12 phase along the grain boundaries. The grain size of the alloy is uniform. With the increase of Sn content, the grain phase Mg2Sn increases. The homogenization treatment makes most of β-Mg17Al12 phase While the residual Mg2Sn and Mg2Pb remain undissolved. Adding Sn can increase the corrosion potential of magnesium alloy and decrease the hydrogen evolution rate. When Sn content is 2wt%, the discharge voltage and current efficiency of magnesium alloy anode are the highest. Due to the “negative difference effect” of magnesium alloy, the rate of hydrogen evolution increases with the increase of current density. When the current density is 10mA / cm2, the current efficiency is the highest, up to 88%. The main components of corrosion products are Mg OH) 2, SnO2 and MgSnO3, and loose, easy to fall, so that the magnesium alloy anode working electrode potential negative and stable, can promote the battery reaction in-depth.