采用感应熔铸+退火处理及快速凝固方法制备了La2Mg0.9Ni7.5Co1.5Al0.1贮氢合金.系统研究了快速凝固对合金的相结构、微观组织及电化学性能的影响.XRD分析表明,随着冷却速率的增加,La2Mg0.9Ni7.5Co1.5Al0.1合金的相组成发生了明显变化.退火合金由αLa2Ni7主相(Ce2Ni7型结构)和少量LaNi3相(PuNi3型结构)组成.随着冷却速率的增加,合金中出现LaNi5相(CaCu5型结构)和LaMgNi4(MgCu4Sn型结构)相,且新相的相丰度增加,αLa2Ni7相和LaNi3相的丰度减少.EPMA分析表明,快速凝固方法制备的La2Mg0.9Ni7.5Co1.5Al0.1贮氢合金为柱状晶组织且晶粒细小.合金电极的电化学测试表明,冷却速率对合金的活化性能影响不大.随冷却速率的增加,合金的最大放电容量减少、高倍率放电性能下降.在较低的冷却速率下(5 m/s),合金电极的循环稳定性改善不明显,而随着凝固速度的进一步增加(20 m/s),合金电极表现出较好的循环稳定性.
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