无Co稀土系储氢合金La(NiM)_(5+x)的组织结构及MH电极性能研究  

Investigation of microstructure and MH electrode properties of Co-free rare-earth hydrogen storage alloys La(NiM)_(5+x)

作　　者：罗永春[1] 王大辉[1] 阎汝煦[1] 杨妹娟[1] 康龙[1] 陈剑虹[1] 

机构地区：[1]甘肃工业大学材料科学与工程学院,甘肃兰州730050

出　　处：《甘肃工业大学学报》2003年第2期1-4,共4页Journal of Gansu University of Technology

基　　金：甘肃省"十五"科技攻关项目(SZ001 A52 05)

摘　　要：制备和研究了过化学计量比无钴合金La(NiM)5+x(M=Cu,Mn,Al,x=0.3～1.0)在常规熔铸、高温退火+淬火及快速凝固不同制备条件下的组织结构和电化学性能.X射线衍射分析表明,熔铸合金组织均由CaCu5型主相和少量第二相组成;当M为Cu和Mn元素时,退火+淬火处理及快速凝固合金在x=0.3～1.0范围内为单相组织,而含Al合金则很难获得单相组织.电化学实验表明,退火+淬火处理后的合金MH电极具有易活化、电化学容量较高、电极循环稳定性得到不同程度改善,其中以含Cu和Mn元素的单相组织合金循环稳定性最好.快速凝固合金均大大提高了合金的电化学稳定性,但其活化性能和电极容量明显下降.The Cofree overstoichiometric alloys La(NiM)1+x(M=Cu, Mn, Al. x=0.3～1) are prepared by means of vacuum arc melting followed by high temperature annealing and quenching or melt spinning method. Their microstructure and electrochemical properties are then investigated comparatively. XRD analysis shows that the ascast alloys are composed of main phase with CaCu5 type structure and a few secondary phase (only contains two elements Ni and M). The alloys La(NiM)5+x with Cu and Mn additions, which are prepared by annealing followed by quenching and melt spinning, present a single phase with CaCu5 type structure in wide range of x value , but it is hard to obtain the single phase with Al addition. The electrochemical analysis shows that the annealed alloys have better activation behavior and higher discharge capacity than that of ascast alloys, its cycling stability are best in the case of Mn and Cu addition. The alloys prepared by melt spinning show a well improved cycling stability, but a lower discharge capacity and worse activation kinetics than that of the annealed alloys.

关 键 词：无钴稀土 储氢合金 镧镍合金 组织结构 金相 MH电极 退火处理 单相组织 循环稳定性 快速凝固非平衡制备法 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG146.45[金属学及工艺—合金]