Nanocrystallization and hydrogen storage in rapidly solidified Mg–Ni–RE alloys
Nanocrystallization and hydrogen storage in rapidly solidified Mg–Ni–RE alloys
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DOI：
10.1016/s0925-8388(01)01745-5
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发表时间：
2002-02
影响因子：
6.2
通讯作者：
T. Spassov;V. Rangelova;N. Neykov
中科院分区：
文献类型：
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作者：
T. Spassov;V. Rangelova;N. Neykov
研究了快速凝固镁基Mg-Ni-RE （RE=Y或Mm）合金的储氢性能。淬火态合金为非晶或纳米/非晶，由纳米晶体（平均尺寸为3nm）嵌入大量的非晶相组成。主要比较了mg76ni19y5和mg78ni18y4合金的加氢性能（储氢容量和加氢动力学）与最近报道的Mg75Ni20Mm5（Mm=Ce， la -富混合金属）的加氢性能。在Mg-Ni-RE合金中，具有上述成分的合金具有最佳的氢化性能。富镧铈混合稀土对储氢能力的影响大于Y。这些合金的结晶通过亚稳fcc Mg6Ni相形成纳米晶材料，而mg78ni18y4合金的纳米结构和中间相热稳定性更强。研究了非等温条件下的结晶动力学，比较了不同镁合金的结晶动力学参数。前人和本研究的结果表明，通过控制非晶或纳米/非晶镁基Mg-Ni-RE前驱体的结晶可以制备出适合储氢的稳定的纳米晶微观结构。
Hydrogen storage in rapidly solidified magnesium based Mg–Ni–RE (RE=Y or Mm) alloys was studied. The as-quenched alloys were amorphous or nano-/amorphous, consisting of nanocrystals (with average size of 3 nm) embedded in large amounts of amorphous phase. The hydrogenation properties (hydrogen storage capacity and hydrogenation kinetics) of Mg76Ni19Y5and Mg78Ni18Y4alloys were compared mainly with those of Mg75Ni20Mm5(Mm=Ce, La-rich mischmetal), reported recently. Alloys with the above mentioned compositions were found to attain the best hydriding characteristics among the Mg–Ni–RE alloys. A more beneficial effect on the hydrogen storage capacity of Mm (La,Ce-rich mischmetal) than Y was detected. Crystallization of these alloys leads to a nanocrystalline material through a metastable fcc Mg6Ni phase, as for the Mg78Ni18Y4alloy the nanostructure and the intermediate phase are thermally more stable. The kinetics of crystallization was studied at non-isothermal conditions and the kinetic parameters for different magnesium alloys were compared. The results from previous and the present study show that stable nanocrystalline microstructures appropriate for hydrogen storage can be produced by controlled crystallization of amorphous or nano-/amorphous magnesium based Mg–Ni–RE precursors.