In合金化及固溶处理对Mg-6Al-1Zn阳极材料组织和电化学性能的影响  

Effect of In and Solid Solution Treatment on Microstructure and Electrochemical Properties of Mg-6Al-1Zn Alloy Anode

作　　者：谷亚啸 江静华[1] 谢秋媛 马爱斌[1,2] 高正 GU Ya-xiao;JIANG Jing-hua;XIE Qiu-yuan;MA Ai-bin;GAO Zheng(College of Mechanics and Materials,Hohai University,Nanjing 211100,China;Suqian Institute,Hohai University,Jiangsu Suqian 223800,China)

机构地区：[1]河海大学力学与材料学院,南京211100 [2]宿迁市河海大学研究院,江苏宿迁223800

出　　处：《表面技术》2022年第11期412-422,共11页Surface Technology

基　　金：国家自然科学基金(51979099);江苏省重点研发计划项目(BE2017148);江苏省自然科学基金(BK20191303)。

摘　　要：目的研究合金化及后续热处理下的镁阳极电化学性能,开发出一种新型镁合金阳极材料。方法利用熔炼法制备Mg-6%Al-1%Zn-0.5%In(质量分数)并做海水激活电池阳极材料,采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)和一系列电化学测试方法研究在3.5%NaCl溶液中In元素的添加和后续固溶处理对Mg-6%Al-1%Zn(AZ61)合金显微组织及其电化学性能的影响。结果合金元素In的添加及后续热处理可提升镁阳极的放电活性和利用效率。AZ61+0.5%In合金经420℃固溶16 h后,在10 mA/cm^(2)和50 mA/cm^(2)下有更负的平均放电电位,分别为-1.545 V(vs.SHE)和-1.229 V(vs.SHE),利用效率在2种电流密度下分别达56.2%与59.3%。结论向AZ61合金中加入0.5%In,其会与Al存在竞争溶解机制,促进第二相Mg_(17)Al_(12)的生成。不连续分布的第二相和In自身的溶解-再沉积作用破坏了腐蚀产物膜的连续性,大幅提升了AZ61的放电活性。经420℃固溶处理16 h后,可在不增大晶粒尺寸的前提下使得第二相Mg_(17)Al_(12)基本溶入基体。此时腐蚀产物膜的稳定性进一步降低,合金成分更均匀,镁阳极的放电活性也得以提升。Seawater-activated battery has received tremendous attention due to the increasing demand for underwater devices.Mg alloy is one of the promising candidates for seawater-activated battery anodes due to the favorable electrochemical characteristics,such as a relatively negative electrode potential(-2.37 V vs.standard hydrogen electrode(SHE)),high theoretical specific capacity(2189 mAh/g),and low density(1.74 g/cm^(3)).However,the Mg-based anodes always exhibit severe self-discharge in the aqueous electrolyte and the generated products adhered to the anode strongly impede the active dissolution of anode materials.The intent of this work is to study the effect of indium addition and subsequent heat treatment on the electrochemical properties of magnesium anode,thus develop a novel magnesium anode material.Prepare the experimental AZI alloy by melting commercial AZ61 and pre-weighed 0.5wt.%In at 993 K in a resistance furnace.Inject the mixed atmosphere of CO_(2) and SF_(6) to prevent the molten metal from burning in air.Next,the molten metal is poured into a preheated mold(493 K)to remove the water in the mold,and then quenched in the water.The as-cast Mg-Al-Zn-In ingot is dimidiated,one-half experiences homogenization(420℃ for 16 h+water quenching)heat treatment,and then denoted as AZIT.Analyze the actual chemical composition of experimental alloy via inductively coupled plasma atomic emission spectrometry(ICP-AES)and identify the crystalline phases by an X-ray diffraction meter(XRD)using Cu KαX-ray radiation from 10°to 90°with a scan speed of 1.5(°)/min.Before OM and SEM observations,the samples are successively ground to 2000 girt SiC papers,followed by mechanical polishing with 1.5μm diamond suspension,and then etched with a solution composition of 1 mL acetic acid+0.42 g picric+7 mL ethanol+1 mL distilled water.Prior to conducting the electrochemical tests,the samples are encapsulated in epoxy resin expect for a 10 mm×10 mm exposed surface.All the electrochemical tests,if not specified,are conducted at 2

关 键 词：镁合金阳极 固溶处理 合金化 放电活性 第二相 

分 类 号：TG172[金属学及工艺—金属表面处理]