快淬纳米晶/非晶Mg_2Ni型合金的电化学贮氢性能

用快淬工艺制备了Mg2Ni型Mg2-xLaxNi（x=0,0.2）贮氢合金,用XRD、SEM、HRTEM等方法分析了合金的微观结构,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,表明少量La替代Mg可以显著提高合金的非晶形成能力。电化学测试的结果表明,La替代可显著提高快淬态合金的放电容量、循环稳定性以及高倍率放电能力（HRD）,这主要归因于在快淬态合金中形成纳米晶/非晶结构。

Electrochemical Hydrogen Storage Characteristics of As-spun Nanocrystalline and Amorphous Mg2Ni-type Alloy

Nanocrystalline and amorphous Mg2Ni-type alloys with nominal compositions of Mg2-xLaxNi（x = 0,0.2） are synthesized by melt-spinning technique.The structures of the as-cast and as-spun alloys were studied by XRD and TEM,finding that no amorphous phase is detectable in the as-spun La-free alloy,but the as-spun alloy containing La holds a major amorphous phase,confirming that the substitution of La for Mg evidently intensifies the glass forming ability of the Mg2Ni-type alloy.The electrochemical measurement shows that the substitution of La for Mg significantly improves the electrochemical hydrogen storage performances of the alloys,involving the discharge capacity and the electrochemical cycle stability as well as the high rate dischargeability（HRD）,for which the nanocrystalline and amorphous structure in the alloys produced by melt spinning is mainly responsible.