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为了改善Mg2Ni型合金气态及电化学贮氢动力学性能,用La部分替代合金中的Mg,用快淬技术制备了Mg2-xLaxNi(x=0,0.2,0.4,0.6)合金,用XRD,SEM,HRTEM分析了铸态及快淬态合金的微观结构;用自动控制的Sieverts设备测试了合金的气态贮氢动力学性能,用程控电池测试仪测试了合金的电化学贮氢动力学。结果发现,快淬无La合金具有典型的纳米晶结构,而快淬含La合金显示了以非晶相为主的结构,表明La替代Mg提高Mg2Ni型合金的非晶形成能力。La替代Mg明显地改变Mg2Ni型合金的相组成。当La替代量x=0.4时,合金的主相改变为(La,Mg)Ni3+LaMg3。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,La替代使合金的吸氢动力学降低,但适量的La替代可以明显改善合金的放氢动力学及高倍率放电能力。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。
Mg2-xLaxNi (x = 0,0.2,0.4,0.6) alloys were prepared by rapid quenching in order to improve the kinetics of Gaseous and Electrochemical Hydrogen Storage in Mg2Ni-type alloys. The results of XRD, SEM The microstructures of as-cast and quenched alloys were analyzed by HRTEM. The dynamic hydrogen storage properties of the alloy were tested by the Sieverts device with automatic control. The kinetics of electrochemical hydrogen storage of the alloy was tested by a programmed battery tester. The results show that the quenched La-free alloy has the typical nanocrystalline structure, while the fast-quenched La-containing alloy shows the amorphous-based structure, indicating that the substitution of Mg for La improves the amorphous formability of the Mg2Ni-type alloy. The substitution of La for Mg significantly changed the phase composition of the Mg2Ni-type alloy. When La substitution is x = 0.4, the main phase of the alloy changes to (La, Mg) Ni3 + LaMg3. The kinetics of hydrogen absorption and desorption of the alloy is sensitive to La content and quenching process. La substitution can decrease the hydrogen absorption kinetics of the alloy, but La substitution can significantly improve the hydrogen desorption kinetics and high-rate discharge capacity of the alloy . Appropriate quenching treatment can improve the gas and electrochemical hydrogen storage kinetics, but to obtain the best hydrogen storage kinetics of quenching process is closely related with the composition of the alloy.