热处理温度对AB_5型MlNi3.60Co0.85Mn0.40Al0.15贮氢电极合金微结构和电化学性能的影响

研究了铸态及经加热温度为 12 73～ 13 73K、保温时间 8h和水冷处理后AB5型MlNi3 .60Co 0 .85Mn0 .4 0Al0 .15贮氢电极合金的微结构和电化学性能。结果表明 :铸态合金的显微组织为典型的树枝晶结构 ,经 12 73K处理后合金的显微组织仍为树枝晶 ,但树枝结构不明显 ,经 13 73K处理后合金的显微组织为柱状晶 ;与铸态合金相比 ,经 12 73K处理后合金的活化性能降低 ,电化学容量和高倍率放电性能基本保持不变 ,循环寿命改善 ;经 13 73K处理的合金活化性能降低 ,电化学容量明显减小 ,高倍率放电性能降低 ,循环寿命显著改善。热处理引起合金电化学性能的变化与合金的微结构的改变有关

Effects of heat-treatment temperature on microstructure and electrochemical properties of AB_5 type MlNi3.60 Co0.85 Mn0.40 Al0.15 hydide electrode alloy

The effects of heat treatment with different temperature on the microstructure and electrochemical properties of AB 5 type MlNi 3.60 Co 0.85 Mn 0.40 Al 0.15 hydride electrode alloy were studied systematically. The results show that, the microstructure of as cast alloy is typical dendrite and that of the alloy by heat treatment with 1?273?K is unconspicuous dendrite, and after being heat treatment with 1?373?K, the microstructure of the alloy changes to columnar crystal. As compared with as cast alloy, after being heat treated by 1?273?K, the activation characteristics decrease and the electrochemical stability improves, while both electrochemical capacity and high rate dischargeability almost unchange; after being heat treated by 1?373?K, the activation characteristics decrease appreciably, the electrochemical capacity decreases drastically, the high rate dischargeability decrease slightly, and the electrochemical stability is improved markedly. The change of electrochemical properties of the alloy heat treated at different temperatures is related to the microstructure of the alloy.