非化学计量比对贮氢合金Mm(NiCoMnAl)_5B_x电化学性能的影响

Influences of nonstoichiometric ratio on the electrochemical properties of Mm(NiCoMnAl)_5B_x hydrogen storage alloys

研究了稀土系非化学计量比贮氢合金Mm(NiCoMnAl)5Bx(x=0,0.1,0.2,0.3,0.4)微观结构及电化学性能 ,分析了非化学计量比ｘ对贮氢合金电化学性能的影响 研究结果表明 ,铸态非化学计量比合金Ｍｎ(ＮｉＣｏＭｎＡｌ)5Ｂｘ 具有双相组织 ,主相为ＣａＣｕ5结构相 ,还有少量ＣｅＣｏ4Ｂ第二相 ,第二相的相丰度随ｘ的增加而增大 经 2 2ｍ/ｓ淬速快淬处理后 ,合金中的第二相消失 随非化学计量比ｘ的增加 ,合金的电化学容量下降 ,但活化性能、倍率放电能力循环寿命明显提高 。

The microstructures and electrochemical properties of rare earth based nonstoichiometric hydrogen storage alloys Mm(NiCoMnAl)5Bx(x=0,0.1,0.2,0.3,0.4) were investigated.The influences of nonstoichiometric ratio x on the electrochemical properties of hydrogen storage alloys were analyzed.The experimental results showed that nonstoichiometric Mm(NiCoMnAl)Bx hydrogen storage alloys as cast have a biphase structure,main phase has a CaCu5 structure,a small amount of second phase is CeCo4B,and the amount of second phase increases with the increase of nonstoichiometric ratio x.The second phase in alloys as cast disappeared after rapid quenching with 22 m/s quenching rate.The electrochemical capacity of hydrogen storage alloys decreased with the increase of nonstoichiometric ratio x,but activation performance and high rate discharge capability as well as cycle life of alloys were enhanced obviously,the discharge voltage character was improved slightly.