【作者】 兴长策； 罗永春； 阎汝旭； 王大辉； 康龙；

【Author】 XING Chang-ce, LUO Yong-chun, YAN Ru-xu, WANG Da-hui, KANG Long( Key Laboratory of New Nonferrous Metal Materials, Lanzhou University of Sci and Tech, Lanzhou 730050, China; Institute of Materials Engineering and Chemical Engineering, Liaoning Institute of Technology, Jinzhou 121001, China)

【机构】 兰州理工大学有色金属新材料重点实验室；

【摘要】 系统研究了固相反应烧结方法制备La0.67Mg0.33Ni2.sCo0.5贮氢合金的烧结工艺对该合金的微现组织结构及电化学性能的影响规律.分析和研究了合金的微观组织结构、电化学放电性能及Mg含量的挥发损失问题.XRD和SEM及EPMA分析结果表明,在不同烧结条件下合金均由不含Mg的LaNi5相、富Mg的LaNi3相及一个贫Mg的LaNix(x=3.0-3.8)相三相组成.当烧结温度不超过1203k时合金主相为LaZNi3相,当烧结温度超过1203K,LaNi5相逐步成为主相.原子吸收光谱分析结果表明,烧结温度不超过1203K,Mg元素没有明显损失;当烧结温度超过1203K,会引起Mg的大量挥发损失.电化学性能分析结果表明,烧结温度不超过1203K,合金放电能力主要受合金组织形成与均匀性影响;而烧结温度超过1203K,Mg元素挥发损失成为影响合金放电能力的决定因素.烧结条件为873-1123k保持24h、1203k保持2h,是制备La0.67Mgo.33Ni2.5Co0.5贮氢合金的适宜工艺.用该工艺制备的Lao.67Mg0.33Ni2.5Co0.5贮氢合金Mg含量稳定(2.92%质量分数)、微观组织均匀、放电容量高(395mAk/g)、活化性能好(2个循环).更多还原

【Abstract】 In this paper, La0.67Mg0.33Ni2.5Co0.5 alloy was synthesized by sintering with temperature stepwise way. The sintering conditions and the micro-structural and electrochemical properties of the alloy has been studied systematically. From the XRD and SEM analyses, it shows that the alloy is composed of the LaNi5 phase without Mg, the LaNi3 phase with abundance in Mg and a phase with shortage of Mg on various sintering conditions. From the AAS analysis, when sintering temperature is no higher than 1203K, the amount of Mg of the alloy is stable, while sintering temperature is higher than 1203K, the amount of Mg of the alloy decreases. The electrochemical properties show that discharge capacity of the alloy varies with structure, when sintering temperature is no higher than 1203K, and discharge capacity of the alloy manly varies with the amount of Mg of the alloy, when sintering temperature is higher than 1203K. It is suitable sintering condition for the alloy that the spanning of sintering temperature range 873-1123k is no less than 24 hours and the spending of sintering temperature 1203k is 2 hours. By this way, the properties of La0.67Mg0.33Ni2.5Co0.5 alloy include stable the amount of Mg, average structure, good activation (2cycle numbers) and high discharge capacity (395mAh/g).更多还原