贮氢电极合金性能的影响
(1. 北京有色金属研究总院 粉末冶金及特种材料研究所，北京100088；
2. 北京科技大学 材料科学与工程学院，北京 100083)
摘 要:
关键字: 钕；A2B7型；贮氢电极合金；相结构；p—c—t曲线；电化学性能
La-Mg-Ni system A2B7-type hydrogen storage electrode alloys
（1. Powder Metallurgy and Special Materials Research Department,General Research Institute for
Nonferrous Metals, Beijing 100088, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China）
Abstract:The La0.7−xNdxMg0.3(NiCoAl)3.5 (x=0, 0.1, 0.3, 0.5, 0.7) hydrogen storage electrode alloys were prepared by cold crucible melting under argon gas atmosphere. The phase structure and electrochemical properties of these alloys and the surface of corresponding electrodes were investigated by means of XRD Rietveld method and tri-electrode test system and SEM. Rietveld analyses show that all these alloys consist of hexagonal Ce2Ni7-type main-phase, hexagonal CaCu5-type phase, rhombohedral PuNi3-type phase, cubic MgCu2-type phase and orthorhombic CrB-type phase. The main-phase content increases, and accordingly the CaCu5-type and MgCu2-type phase content decreases, and the PuNi3-type phase content is almost invariable. Furthermore, the cell volume of these phases decreases linearly. p—c—t isotherms show that hydrogen-desorption plateau region narrows with increasing x, and the plateau pressure increases and the plateau becomes firstly steeper then flatter. The electrochemical results show that maximum discharge capacity decreases linearly. The activation property and high-rate dischargeability are favorable. Cyclic stability is improved markedly.
Key words: neodymium; A2B7-type; hydrogen storage electrode alloys; phase structure; p—c—t curves; electrochemical properties
