A侧元素对AB_3型贮氢合金晶体结构的影响  

Effect of A-Side Element on Crystal Structure of AB_3-Type Hydrogen Storage Alloy

作　　者：朱健[1] 张晶[1] 方方[1] 郑时有[1] 陈国荣[1] 孙大林[1] 

机构地区：[1]复旦大学,上海200433

出　　处：《稀有金属材料与工程》2008年第8期1377-1379,共3页Rare Metal Materials and Engineering

基　　金：上海市科学技术委员会国际合作资助项目(045207034)

摘　　要：以AB3型贮氢合金中的LaNi3合金为参考相,选取CeNi3、LaY2Ni9和CeY2Ni93种合金为研究对象,运用X射线衍射技术结合Rietveld结构精修的方法,研究了A侧元素对AB3型贮氢合金晶体结构的影响。研究表明,LaNi3、LaY2Ni9和CeY2Ni9的晶体结构均与PuNi3型结构相吻合,具有R-3m的空间点群,而CeNi3的空间点群则为P63/mmc。与LaNi3相比,LaY2Ni9合金的点阵常数a和c分别减小了0.7%和2.0%,晶胞体积减小了3.3%;与CeY2Ni9相比,LaY2Ni9合金的点阵常数a减小了0.9%,c增加了0.7%,晶胞体积减小了1.2%。A侧原子的点阵位置具有选择性,即原子半径大的原子倾向于占据点阵中3a位置,半径小的原子倾向于占据6c位置。As the representive for AB3-type intermetallics, CeNi3, LaY2Ni9 and CeY2Nig, have been studied and compared with LaNi3. The effect of A-side element on crystal structure of AB3-type compounds was investigated by means of X-ray diffraction and Rietveld structure refinement. The results indicate that LaNi3, LaY2Ni9 and CeY2Ni9 adopt a rhombohedral structure of PuNi3-type （R-3m space group）, while the space group of CeNi3 is P63/mmc. As compared to LaNi3, LaY2Ni9 shows isotropic variations in the cell parameters, with the decrease of 0.7% in α, and 2.0% in c, which leads to the cell volume reduction of 3.3%. Compared to CeY2Nig, LaY2Ni9 shows a decrease of 0.9% in α, and the increase of 2.0% in c, and an overall cell volume reduction of 1.2%. Among the two available crystallographic sites for A-side atom, the atom with a larger radius occupies the site 3α preferentially and the smaller one occupies the site 6c in the lattice.

关 键 词：AB3型贮氢合金 稀土元素 X射线衍射 RIETVELD结构精修 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG146.4[金属学及工艺—合金]