Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1623916 | Journal of Alloys and Compounds | 2008 | 7 Pages |
Abstract
In order to improve the cycle stability of the La-Mg-Ni system PuNi3-type hydrogen storage electrode alloys, Ni in the alloy was partially substituted by Fe. The La0.7Mg0.3Co0.45Ni2.55âxFex (x = 0, 0.1, 0.2, 0.3, 0.4) hydrogen storage alloys were prepared by casting and rapid quenching. The effects of the substitution of Fe for Ni on the structures and electrochemical performances of the as-cast and quenched alloys were investigated in detail. The results of the electrochemical measurement indicate that the substitution of Fe for Ni obviously decreases the discharge capacity, high rate discharge capability (HRD) and discharge potential of the as-cast and quenched alloys, but it significantly improves their cycle stabilities, and its positive impact on the cycle life of as-quenched alloy is much more significant than on that of the as-cast one. The microstructure of the alloys analyzed by XRD, SEM and TEM show that the as-cast and quenched alloys have a multiphase structure which is composed of two major phases (La, Mg)Ni3 and LaNi5 as well as a residual phase LaNi2. The substitution of Fe for Ni helps the formation of a like amorphous structure in the as-quenched alloy. With the increase of Fe content, the grain sizes of the as-quenched alloys significantly reduce, and the lattice constants and cell volumes of the alloys obviously increase.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Yang-Huan Zhang, Bao-Wei Li, Hui-Ping Ren, Zhong-Wang Wu, Xiao-Ping Dong, Xin-Lin Wang,