摘要
以La0.8Mg0.2Ni2.8Co0.6合金为基材,采用感应熔炼法制得以Ce,Pr,Nd部分替代La的系列储氢合金。3种稀土元素的加入对合金的组织没有本质的影响。与La0.8Mg0.2Ni2.8Co0.6的相组成相似,新合金也是在主相LaNi5中含有LaNi3第二相,且随着Ce,Pr,Nd替换量的增多,LaNi3相所占比例升高。在La0.8-xRExMg0.2Ni2.8Co0.6合金中,当Pr替换至x=0.2时,新合金基本保持La0.8Mg0.2Ni2.8Co0.6的放电容量375mA·h/g;其他添加比例及添加元素都在一定程度上降低了新合金的放电容量。加入Ce和Pr普遍提高放电电位,而Nd对放电电位的影响不大。La0.8Mg0.2Ni2.8Co0.6的容量衰减速率为1.07mA·h/(g·cycle),当Ce,Pr,Nd分别替换至x=0.3,0.6,0.6时,新合金的容量衰减速率依次降低到0.566,0.625,0.453mA·h/(g·cycle),循环稳定性有了很大提高。
A new series hydrogen storage alloys with elements Ce, Pr and Nd replacing La in alloy La0.8Mg0.2Ni2.8Co0.6 were obtained by electric induction melting. The addition of three rare earth elements has no significant influence on microstructures of the new alloys and the microstructures of new alloys are similar to that of La0.8Mg0.2Ni2.8Co0.6, LaNi5 phase with LaNi3 is as secondary phase; LaNi3 phase increases with the increases of amount of Ce, Pr, Nd. In La0.8-xRExMg0.2Ni2.8Co0.6 alloys the discharge capacities of the new alloys keep no change on 375 mA·h/g, with only Pr addition to x=0.2; the other elements make the capacities decrease. The introduction of Ce, Pr makes the discharge voltage increases, while Nd shows less effect. Compared with the capacity decay rate of 1.07 mA·h/(g·cycle) for the alloy La0.8Mg0.2Ni2.8Co0.6, the capacity decay rates of the new alloys are 0.566, 0.625 and 0.453 mA·h/(g.cycle) with Ce, Pr and Nd addition to x=0.3, 0.6 and 0.6, respectively, which shows the stability of charging/discharging cycle is improved obviously.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2003年第4期871-875,共5页
The Chinese Journal of Nonferrous Metals
关键词
储氢合金
稀土
放电容量
循环稳定性
hydrogen storage alloy
discharge capacity
cycle stability
rare earth element
