【摘要】 研究了 Ｃｒ部分替代 Ｍｎ对 Ｔｉ－Ｚｒ－Ｖ－Ｍｎ－Ｎｉ贮氢合金相结构、显微组织及电化学性能的影响．结果表明，随着Ｃｒ的加入，合金电极的循环稳定性得到明显改善，但电极放电容量有所下降.ＸＲＤ及 ＥＤＳ分析表明，合金主要由六方结构的Ｃ１４ Ｌａｖｅｓ母相和立方结构的ＴｉＮｉ型第二相构成，Ｃｒ替代后，合金中出现了立方结构的Ｖ－Ｃｒ固溶相 金相显微组织显示，铸态和退火态合金均由连续的 Ｃ１４ Ｌａｖｅｓ相基体以及 ＴｉＮｉ型树枝晶第二相组成．更多还原

【Abstract】 AB2 type Ti-Zr-V-Mn-Ni-based Laves phase hydrogen storage alloys have a very high initial electrochemical discharge capacity, but the capacity decreases drastically within several charging-discharging cycles in KOH electrolyte which impede their applications as the negative elec- trode materials in Ni-MH batteries. In is work, Mn was partially substituted by Cr in the Ti-Zr-V- Mn-Ni hydrogen storage alloy and the effects of Cr substitution on the phase structure, microstructure and electrochemical properties of the alloys have been investigated. It is found that the cycle durability of the alloy electrodes have been greatly improved with Cr substitution despite the decrease of dis- charge capacities. Based on the XRD and EDS analysis, the alloys are mainly composed of C14 Laves phase matrix with hexagonal structure and TiNi type secondary phase with bcc structure. With Cr substitution, another V-Cr solid solution with bcc structure appears. The metallographic observation shows that both the as cast and annealed alloys consist of a continuous C14 Laves phase matrix and TiNi type secondary phase with dendritic structure.更多还原