热处理对Nd-Mg-Ni储氢合金结构和性能的影响  

Effect of Heat Treatment on Structure and Properties of Nd-Mg-Ni-System Hydrogen Storage Electrode Alloys

作　　者：苑慧萍[1] 李志念[1] 赵旭山[1] 王树茂[1] 刘晓鹏[1] 蒋利军[1] 

机构地区：[1]北京有色金属研究总院能源材料与技术研究所,北京100088

出　　处：《稀有金属》2013年第3期341-347,共7页Chinese Journal of Rare Metals

基　　金：国家科技部863计划(2011AA03A408)资助项目

摘　　要：采用磁悬浮感应熔炼法制备了Nd-Mg-Ni系储氢合金,重点研究了热处理工艺对合金相组成和电化学性能的影响。采用X射线衍射、扫描电镜和电化学测试系统研究了合金的相结构、显微结构及电化学性能。研究结果表明,Nd0.75Mg0.25Ni2.75Al0.25合金经1173,1273,1373 K退火处理后,随着退火温度的升高,不同相间元素分布更加均匀,Mg元素的浓度差减小,主相Nd2Ni7六方相逐渐增加。电化学P-C-T曲线平台变平缓、平台压降低,电化学容量,倍率性能和荷电保持率有较大提升。对于Nd0.75Mg0.25Ni3.2Al0.1合金,经1373 K,5 h热处理后慢冷较快冷更利于Nd2Ni7相的形成,慢冷试样中Nd2Ni7相可达92.31%,电化学性能更加优异,最大电化学容量为330.1 mA.g-1,循环100周容量保持率为92.2%。The as-cast Nd-Mg-Ni-system hydrogen storage electrode alloy was prepared by vacuum induction levitation melting meth- od. The influence of heat treatment on the phase components and the electrochemical properties was investigated. The XRD, SEM, andelectrochemical tests were used to study the phase structure, microscopic structure, and the electrochemcial properties of the alloys. After heat treatment at 1173, 1273, and 1373 K, it was found that the element distribution became uniform and the concentrationdifference of Mg element in different phases decreased with the increase of the heat treatment temperature. The hexagonal Nd2 Ni7-type main-phase content increased. The P-C-T curves became smoothly and the plateau pressure descended. The electrochemical capacity,high rate dischargeability, and the charge retention were improved with the increase of the heat treatment temperature. For Nd0.75 Mg0. 25 Ni3.2Al0.1 hydrogen storage electrode alloy, the slow cooling method after heat treatment at 1373 K for 5 h was in favor of the formationof Nd2 Ni7 phase, better than the fast cooling method. The Nd2 Ni7 phase content could reach to 92.31%, the maximum discharge capacity was 330.1 mA·g^-1 , and the charge retainion after 100 cycles was 92.2%.

关 键 词：热处理 储氢电极合金 相结构 相成分 Nd-Mg-Ni系 

分 类 号：TG146.4[一般工业技术—材料科学与工程] TG139.7[金属学及工艺—金属材料]