用快淬工艺制备了Mg2Ni型纳米晶合金,合金的成分为Mg20Ni10-xCux(x=0, 1, 2, 3, 4)。用XRD、SEM、HRTEM分析了铸态及快淬态合金的微观结构,采用程控电池测试仪测试了合金电极的电化学性能,并用自动控制的Sieverts设备测试了合金的吸放氢动力学性能。结果表明,所有的快淬态合金具有纳米晶结构,Cu替代Ni不改变合金的Mg2Ni型主相,但显著地改善了合金的电化学贮氢性能,包括放电容量和电化学循环稳定性。此外,合金的吸氢量随Cu含量的增加先上升后下降,而合金的放氢量随Cu含量的增加而增加。
The nanocrystalline Mg2Ni-type alloys with the compositions of Mg20Ni10-xCux (x=0, 1, 2, 3, 4) were synthesized by melt spinning technique. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The electrochemical hydrogen storage performances were tested by an automatic galvanostatic system, and their hydriding and dehydriding kinetics were measured by an automatically controlled Sievert's apparatus. The results show that all the as-spun alloys hold a typical nanocrystalline structure. The substitution of Cu for Ni improves the electrochemical hydrogen storage performances of the alloys significantly, involving both the discharge capacity and the electrochemical cycle stability. Furthermore, the hydrogen absorption capacity of the alloy first increases and then decreases with the rising of Cu content, but the hydrogen desorption capacity grows dramatically for the same reason.