Cycle stabilities of the La0.7Mg0.3Ni2.55−xCo0.45Mx (M = Fe, Mn, Al; x = 0, 0.1) electrode alloys prepared by casting and rapid quenching
Cycle stabilities of the La0.7Mg0.3Ni2.55−xCo0.45Mx (M = Fe, Mn, Al; x = 0, 0.1) electrode alloys prepared by casting and rapid quenching
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DOI：
10.1016/j.jallcom.2007.03.091
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发表时间：
2008-06
影响因子：
6.2
通讯作者：
Yang-huan Zhang;Bao-wei Li;H. Ren;Y. Cai;Xiaoping Dong;Xin-lin Wang
中科院分区：
文献类型：
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作者：
Yang-huan Zhang;Bao-wei Li;H. Ren;Y. Cai;Xiaoping Dong;Xin-lin Wang
为了提高La-Mg-Ni系（PuNi 3型）贮氢合金的循环稳定性，采用Fe、Mn和Al部分替代合金中的Ni，并采用铸造和快淬工艺制备了电极合金La0.7Mg0.3Ni2.55−xCo0.45Mx（M=Fe，Mn，Al; x=0，0.1）。研究了Fe、Mn、Al替代Ni和快淬对合金组织和电化学性能的影响。XRD、SEM和TEM分析结果表明，元素替代对合金的相组成没有影响，但改变了合金的相丰度。特别是Al和Mn的替代明显提高了LaNi_2相的含量。Al和Fe的替代导致淬火态合金的晶粒显著细化。Al的替代强烈地抑制了淬火态合金中非晶的形成，而Fe的替代对非晶相的形成有很大的帮助。Fe、Mn和Al的替代对铸态和淬火态合金循环稳定性的影响不同。替代元素对铸态合金循环稳定性的影响顺序为Al>Fe>Mn，对淬火态合金循环稳定性的影响顺序为Fe>Al>Mn。快淬对合金的相组成影响不大，但显著提高了合金的循环稳定性。
In order to improve the cycle stability of La–Mg–Ni system (PuNi3-type) hydrogen storage alloy, Ni in the alloy was partly substituted by Fe, Mn and Al, and the electrode alloys La0.7Mg0.3Ni2.55−xCo0.45Mx(M=Fe, Mn, Al; x=0, 0.1) were prepared by casting and rapid quenching. The effects of the substitution of Fe, Mn and Al for Ni and rapid quenching on the microstructures and electrochemical properties of the alloys were investigated in detail. The results obtained by XRD, SEM and TEM indicate that element substitution has no influence on the phase compositions of the alloys, but it changes the phase abundances of the alloys. Particularly, the substitution of Al and Mn obviously raises the amount of the LaNi2phase. The substitution of Al and Fe leads to a significant refinement of the as-quenched alloy's grains. The substitution of Al strongly restrains the formation of an amorphous in the as-quenched alloy, but the substitution of Fe is quite helpful for the formation of an amorphous phase. The effects of the substitution of Fe, Mn and Al on the cycle stabilities of the as-cast and quenched alloys are different. The positive influence of the substitution elements on the cycle stabilities of the as-cast alloys is in proper order Al>Fe>Mn, and for as-quenched alloys, the order is Fe>Al>Mn. Rapid quenching engenders an inappreciable influence on the phase composition, but it markedly enhances the cycle stabilities of the alloys.