摘要
以La0.6R0.2Mg0.2Ni2.8Co0.2Al0.2Mn0.1(R=La、Ce、Pr、Nd、Y)合金为研究对象,研究稀土元素R部分替代La后对合金相结构和相组成及电化学性能的影响。X射线衍射(XRD)和显微电子探针(EPMA)方法分析结果表明,合金La0.8Mg0.2Ni2.8Co0.2Al0.2Mn0.1退火组织主要由Ce2Ni7型相(或Gd2Co7型)、PuNi3型相和CaCu5型相组成;Pr、Ce、Nd元素的替代对合金的相组成没有明显影响,而Y元素替代使合金中CaCu5型相明显减少,Ce2Ni7型(或Gd2Co7型)相显著增加,其相丰度达到79.03%。Y元素替代时合金中Gd2Co7型相基本消失。电化学测试和分析表明,稀土元素R替代La后对合金电极活化性能影响不大,其中Pr、Nd、Y部分替代La在一定程度上提高了合金的最大放电容量,而元素Y替代时合金电极容量最高达到392.6mAh/g;Y元素部分替代La使合金电极的循环稳定性得到明显提高,S100达到90.3%。
La0.6R0.2Mg0.2(NiCoAlMn)3.3 hydrogen storage alloys were prepared by induction melting and then treated by annealing process, and effects of rare earth R (R is La, Ce, Pr, Nd and Y) substituted for La on the structure and electro-chemical properties were investigated by XRD (X-ray diffraction) and EPMA. The results reveal that the La0.6R0.2Mg0.2(NiCoAlMn)3.3 hydrogen storage alloys consist of CaCu5-type phase as matrix and Ce2Ni7 and PuNi3-type as secondary phase. Addition of Ce, Pr, Nd is not changed the phase constituent of the alloy. However, CaCu5-type phase is decreased and Ce2Ni7-type phase is increased obviously with Y addition, and phase abundance of Ce2Ni7-type phase reaches 79.03%, meanwhile, Y addition can lead to the disappearance of Gd2Co7-type phase. Electrochemical measurements show that activation performance of the alloy is slightly affected by the Ce, Pr, Nd and Y element, however, maximum discharge capacities of the alloy are improved to some extent with Pr, Nd, Y substituted for La partially, in which maximum discharge capacity reaches up to 392.6 mAg/g with Y. In addition, cyclic stability of the alloys with Y substituted for La is increased obviously, increased by 90.3%.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2011年第3期255-259,193,共5页
Special Casting & Nonferrous Alloys
基金
太原科技大学校青年科学基金资助项目(20093006)
关键词
稀土-镁-镍基储氢合金
微观组织
电化学性能
La-R-Mg-Ni Based Hydrogen Storage Alloy, Microstructure, Electrochemical Property
