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用铸造及快淬工艺制备Mg2Ni型Mg2-xLaxNi(x=0,0.2,0.4,0.6)贮氢合金。用XRD、SEM、HRTEM分析铸态及快淬态合金的微观结构。结果发现,在快淬无La合金中没有出现非晶相,但快淬含La合金显示了以非晶相为主的结构。用DSC研究快淬合金的热稳定性,表明La的含量及快淬对非晶相的晶化温度影响很小。电化学测试结果表明,铸态合金的放电容量随La含量的增加而增加,快淬态合金的放电容量随La含量的变化有极大值。La替代Mg显著地提高了铸态及快淬态合金的循环稳定性。
Mg2Ni-type Mg2-xLaxNi (x = 0,0.2,0.4,0.6) hydrogen storage alloy was prepared by casting and rapid quenching process. The microstructures of as-cast and quenched alloys were analyzed by XRD, SEM and HRTEM. As a result, it was found that no amorphous phase did not appear in the quenched La-free alloy, but the quenched La-containing alloy showed the amorphous-based structure. DSC study of the thermal stability of quenched alloys, indicating that the content of La and quenching on the crystallization temperature of the amorphous phase has little effect. The results of electrochemical tests show that the discharge capacity of as-cast alloy increases with the increase of La content. The discharge capacity of quenched alloy has a maximum with the change of La content. The substitution of La for Mg significantly improves the cycling stability of as-cast and quenched alloys.