Effect of substitution of Nd for Mg on the hydrogen storage properties of Mg2Ni alloy
Effect of substitution of Nd for Mg on the hydrogen storage properties of Mg2Ni alloy
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DOI：
10.1016/j.jallcom.2008.12.018
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发表时间：
2009-06
影响因子：
6.2
通讯作者：
D. Xie;Pei Li;C. Zeng;J. Sun;X. Qu
中科院分区：
文献类型：
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作者：
D. Xie;Pei Li;C. Zeng;J. Sun;X. Qu
在高纯氦气保护下，采用真空感应熔炼法制备了Mg 2 −xNdxNi（x=0，0.1，0.2，0.3）贮氢合金。通过X射线衍射（XRD）、扫描电镜（SEM）和压力温度实验（PCT）对样品的相结构、形貌和储氢性能进行了研究。XRD和SEM分析结果表明，Mg-Nd-Ni合金为Mg 2Ni、Nd 2Ni 7、NdMg 12或Nd 5 Mg 41等多相结构。结果表明，该合金具有良好的活化性能、平台特性、吸放氢可逆性和动力学性能。Nd替代Mg后，Mg 2Ni合金的储氢性能得到明显改善，并保持了较高的储氢容量。Mg-Nd-Ni合金的压力成分等温线（PCIs）显示出两个平台，较低和较窄的平台对应于MgH 2的形成，较高和较宽的平台对应于Mg 2NiH 4的形成。在Mg-Nd-Ni合金中，Mg1.9Nd0.1Ni合金具有最好的吸放氢动力学、最高的储氢量和良好的可逆性。
Hydrogen storage alloys Mg2−xNdxNi (x=0, 0.1, 0.2, 0.3) were prepared by vacuum induction melting under the protection of high purity helium atmosphere. Their phase structures, morphologies and hydrogen storage properties were intensively studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and pressure composition and temperature (PCT) experiments in the present work. XRD and SEM analysis results show that the Mg–Nd–Ni alloys appear multiphase structures involving Mg2Ni, Nd2Ni7, NdMg12or Nd5Mg41and other minor phases. It was found that the alloys exhibited good activation behavior, plateau characteristics, and hydrogen absorption–desorption reversibility and kinetic properties. The substitution of Nd for Mg has improved the hydrogen storage properties of Mg2Ni evidently and kept relative high hydrogen capacities. The pressure composition isotherms (PCIs) of the Mg–Nd–Ni alloys display two plateaus, the lower and narrow ones corresponding to MgH2formation and the higher and broad ones corresponding to Mg2NiH4formation. Among the Mg–Nd–Ni alloys, the Mg1.9Nd0.1Ni alloy has the best hydrogen absorption and desorption kinetics, the highest hydrogen capacity and good reversibility.