贮氢合金Zr(Mn_(l-x)Ni_x)_2的相结构

PHASE COMPOSITION FOR Zr(Mn_(l-x)Ni_x)_2 ALLOYS

贮氢合金Zr（Mnl－xNix）2（0.40≤x≤0．75）的多相Rietveld分析表明，它是以C15型Laves相ZrM2为主的多相体系、不同M／Zr原子比（M=Nix或Mnl-x）非Laves相合金的出现与丰度和整个合金成分配比中Ni／Zr原子比的变化一致，并与Ni－Zr相图中具有同样Ni／Zr原子比的金属间化合物有相同的晶型．x＝0．75，Zr7M10的丰度是38.57％;x＝0.55，C15Laves相的最大丰度达85.98％，电化学放电容量也达最大值242mAh／g;≥0.55，C14型Laves相丰度在2％左右；x＜0．55；C14型Laves相丰度随Mn取代量的增加而增加；x＝0．40，丰度是26.38％．

The phase composition of Zr(Mn1-xNix)2 (0.4≤x ≤0.75) alloys has been revealedby means of multi-phase Rietveld analysis. The major phase in this alloy series is C15-type Lavesphase. The minor phases are C14-type Laves phases, intermetallic compounds Zr7M10. Zr9 M11, ZrM,Zro2 and ZrO. The appearance of non-Laves phase and the variation of abundance for difFerent M/Zratomic ratio correspond with the change of Ni/Zr atomic ratio in the alloy component, its crystal typeis the same as the intermetalic compound in Ni-Zr phase diagram. When x=0.75, the abundanceof Zr7M10 is 38.57%; x=0.55, the largest abundance of C15 Laves phase is 85.98%, and the largest electric chemical discharge capacity is 242mAh/g; x ≥0.55, anundance of C14 Laves phase is 2% or so;x <0.55, abundance of C14 phase increases with the increasing of x, x=0.40. it's abundance is 26.38%.The appearance of C15 Laves and the variation of abundance can be interpreted by the variation ofaverage valence electronic number in the ZrM2, which changes with the increasing and decreasing ofsubstitution amount x of Ni.