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RE-Mg-Ni系A2B7型合金的循环稳定性及电化学贮氢动力学

ISSN号：1001-1560
期刊名称：《材料保护》
时间：0
分类：TG139.7[金属学及工艺—合金;一般工业技术—材料科学与工程;金属学及工艺—金属学] TM912.2[电气工程—电力电子与电力传动]
作者机构：[1]内蒙古科技大学省部共建国家重点实验室培育基地,内蒙古包头014010
相关基金：国家“863计划”十二五稀土重大专项项目（2011AA03A408）;国家自然科学基金资助项目（51161015和50961009）;内蒙古自然科学基金重点资助项目（2011ZDl0）

作者：张羊换[1], 侯忠辉[1], 张国芳[1], 李霞[1], 胡锋[1], 蔡颖[1], 张胤[1]

关键词： A2B7, 型贮氢合金, 熔体快淬, 微观结构, 循环稳定性, 动力学, A2 B7-type alloy, melt-spinning, structure, cycle stability, electrochemical kinetics

中文摘要：

为了改善La-Mg-Ni系A2B7电极合金的电化学循环稳定性，用Zr部分替代合金中的La，并采用熔体快淬技术制备了La0.75-xZrxMg0.25Ni3.2Co0.2Al0.1（x=O，0．05，0．1，0．15，0．2）电极合金．用XRD，TEM分析了合金的微观结构，结果表明，快淬不含zr合金具有完全的纳米晶结构，而快淬含Zr合金中出现明显的非晶相，证明zr替代有利于提高合金的非晶形成能力．铸态及快淬态合金均具有多相结构，包括两个主相（La，Mg）2Ni7及LaNi5和残余相LaNi2，Zr替代及快淬导致LaNi5相增加和（La，Mg）2Ni7相减少．Zr替代及快淬处理显著提高了合金的电化学循环稳定性，但快淬明显降低Zr0.2合金的电化学贮氢动力学；随Zr替代量的增加，5m／s快淬合金的电化学贮氢动力学先增加后降低．

英文摘要：

In order to improve the electrochemical cycle stability of the La-Mg-Ni system A2 B7-type electrode alloys, the partial substi- tution of Zr for La has been performed. The La0.75-xZrxMg0.25Ni3.2Co0.2Al0.1 （x = 0, O. 05, 0.1, 0.15, 0.2） electrode alloys were fabricated by casting and melt-spinning. The structure was characterized by XRD and TEM, and the results reveal that the as-spun Zr free alloy displays an entire nanocrystalline structure, but an amorphous structure was detected in the as-spun alloy substituted by Zr, suggesting that the substitution of Zr for La facilitates the amorphous formation. The ascast and spun alloys have a muhiphase struc- ture, composing of two main phases （ La, Mg）2 Ni7 and LaNi5 as well as a residual phase LaNi2 ;the phase abundance of LaNi5 was increased and that of （La, Mg）2 Ni7 was decreased by the substitution of Zr for La. The electrochemical measurement indicates that both the substitution of Zr for La and the melt spinning remarkably ameliorated the electrochemical cycle stability of the alloys, but the melt- spinning treatment decreased the hydrogen storage kinetics of the alloys. The hydrogen storage kinetics of the as-spun （5 m/s） alloys first increased and then decreased by increasing Zr content from 0 to 0.2.