La_(0.63)Gd_(0.2)Mg_(0.17)(,NiCoAl)_x(,x=3.3,3.5)储氢合金的微观组织和电化学性能  

Microstructure and Electrochemical Properties of La_(0.63)Gd_(0.2)Mg_(0.17)(,NiCoAl)_x(,x=3.3,3.5) Hydrogen Storage Alloys

作　　者：吴婷[1] 罗永春[1,2] 康龙[1] 

机构地区：[1]兰州理工大学材料科学及工程学院,兰州730050 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050

出　　处：《中国铸造装备与技术》2010年第5期13-17,共5页China Foundry Machinery & Technology

基　　金：国家自然科学专项基金资助项目;批准号:50941019

摘　　要：采用真空感应熔炼方法制备了La0.63Gd0.2Mg0.17Ni2.85Co0.3Al0.15和La0.63Gd0.2Mg0.17Ni3..05Co0.3Al0.15贮氢合金,并在氩气气氛中和900℃进行退火处理,通过X射线衍射(XRD)、显微电子探针(EPMA)分析方法和电化学测试分析研究了不同化学计量比对合金微观组织和电化学性能的影响。研究结果表明,该系列合金退火组织主要由Ce2Ni7+Gd2Co7型、Pr5Co19型﹑PuNi3型和CaCu5型相组成,AB3.3中Ce2Ni7+Gd2Co7型相明显比AB3.5减少。电化学测试分析表明,不同的化学计量比对合金电极活化性能影响不大,AB3.5合金的最大放电容量大于AB3.3合金。AB3.5合金的循环稳定性明显高于AB3.3合金,经100次充放电循环后其电极容量保持率S100分别为90.2%和83.7%,其中AB3.5合金具有最好的综合电化学性能。La0.63Gd0.2Mg0.17Ni2.85Co0.3Al0.15 and La0.63Gdn2Mg0.17Ni3.05Co0.3Al0.15 hydrogen storage alloys have been prepared by induction melting fllowed by annealing treatment at 900℃ in Ar atomosphere. The effect of difference of stoichiometric ratio on the microstructure and electrochemical properties have been investigated by means of X-ray diffraction （XRD）, electron probe micro-analysis （EPMA） and electrochemical measurements. The results showed that all these alloys mainly consist of Ce2Ni7-type＋ Gd2Co7-type, Pr5Co19-type, PuNi3-type and CaCu5-type phase.AB3.3 alloy leads to a significant decrease in Ce2NiT-type phase abundance and increase in CaCu5-type phase abaundance. The electrochemical measurements showed that the activation performance of alloy electrodes had not greatly been influenced with different stoichiometric ratio. The discharge capacity of the AB3.s alloys was larger than that of the AB3.3 alloys. The cyclic stability of the AB3.5 alloy electrodes was obviously higher than that of the AB3.3 alloys. After 100 charge discharge cycles, the discharge capacity retention rate S100=（C100/Cmax） of the alloy electrodes （x=3.3,3.5） respectively reach to 90.2% and 83.7%. Among the alloys studied, the AB3.5 alloy possessed the best synthetical electrochemical properties.

关 键 词：储氢合金 微观组织 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]