Fe替代Co对AB5型贮氢合金循环稳定性的影响

Effect of Substitution Fe for Co on the Cycle Stability of AB5-Type Hydrogen Storage Alloys

摘要:

用铸造及快淬的方法制备了稀土基AB5型Mm（NiMnSiAl）4．3Co0.6-xFex（x=0，0．1，0．2，0．3，0．4，0．5，0．6）贮氢合金，用XRD。TEM及SEM观测了铸态及快淬态的微观结构，测试了合金在铸态及快淬态下的电化学循环稳定性。研究了Fe替代Co对铸态及快淬态贮氢合金微观结构及循环稳定性的影响。研究结果表明，Fe替代Co对铸态及快淬态合金的相结构没有明显影响，但对合金的循环稳定性产生显著影响。Fe替代Co能不同程度地改善铸态及快淬态合金的循环稳定性，但对快淬态合金循环寿命的改善更加显著，导致这一结果的主要原因是Fe替代Co使快淬态合金的微观组织显著细化。

Abstract:

The rare-earth-based AB5-type Mm(NiMnSiAl)4.3Co0.6-xFex (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) hydrogen storage alloys were prepared by casting and rapid quenching. The microstructures of the as-cast and quenched alloys were analyzed by XRD, SEM and TEM, and electrochemical cycle stability of the as-cast and quenched alloys were measured. The effects of substitution Fe for Co on microstructures and electrochemical cycle stability of the as-cast and quenched alloys were investigated in detail. The obtained results show that the effects of substitution Fe for Co on the phase structures of the as-cast and quenched alloys are imperceptible, but its effects on electrochemical cycle stability of the alloys are notable. The substitution Fe for Co can improve the cycle stability of the as-cast and quenched alloys. Especially, substitution Fe for Co can significantly enhance the cycle lives of the as-quenched alloys, which is mainly attributed to the grain refinement caused by substitution Fe for Co.