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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,合金的气态贮氢动力学性能用自动控制的Sieverts设备测试,并用程控电池测试仪测试合金的电化学贮氢动力学。结果发现,La替代Mg明显地改变Mg2Ni型合金的相组成。当x≤0.2时,La替代Mg不改变合金的主相Mg2Ni,但出现少量的LaMg3及La2Mg17相。当La替代量x≥0.4时,合金的主相改变为(La,Mg)Ni3+LaMg3。快淬含La合金显示了以非晶相为主的结构,表明La替代Mg提高了Mg2Ni型合金的非晶形成能力。合金的气态及电化学吸放氢动力学对La含量及快淬工艺敏感,适当的快淬处理可以提高合金的气态及电化学贮氢动力学,但获得最佳贮氢动力学的快淬工艺与合金的成分密切相关。
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 the as-cast and quenched alloys were characterized by XRD, SEM and HRTEM. The kinetics of the hydrogen storage of the alloys was tested by the Sieverts with automatic control. The electrochemical hydrogen storage kinetics of the alloy was tested by a programmed battery tester. As a result, it was found that La substitution for Mg significantly changed the phase composition of the Mg2Ni-type alloy. When x≤0.2, La substitution Mg does not change Mg2Ni alloy main phase, but a small amount of LaMg3 and La2Mg17 phase. When La substitution x≥0.4, the main phase of the alloy changes to (La, Mg) Ni3 + LaMg3. The quenched La-containing alloys show the amorphous phase-dominated structure, indicating that the substitution of Mg for La improves the amorphous formability of Mg2Ni-type alloys. The kinetics of gas and electrochemical hydrogen absorption and desorption of the alloy are sensitive to the La content and the quenching process. Appropriate quenching can improve the kinetics of the gas and electrochemical hydrogen storage of the alloy, but the quenching process And the composition of the alloy is closely related.