Fe杂质对AB_5型储氢合金电性能的影响

The Influence of Fe Impurity Included in Mischmetal on the Electrochemical Properties of AB_5-Type Alloy

研究了混合稀土中的铁杂质对混合稀土一镍系储氢合金Mm(NiCoMnAl)_5电性能的影响,当铁在稀土中的含量小于0.4w％时,对AB_5型储氢合金的容量、循环寿命、电压平台等性能无明显影响,当Fe在稀土中的含量达0.4w％时,储氢合金的活化性能稍有降低。XRD分析结果表明,稀土中铁含量不超过0.4w％时,合金均为单相CaCu_5型结构,且其晶胞参数均没有改变,SEM结合EDS分析结果表明,稀土中铁含量为0.4w％的合金与稀土中铁含量为0.084w％的合金相比,二者的表面形貌和微观组织均无明显区别。

Fe as a main impurity was always present in mischmetal. The influence of Fe in mischmetal on the electrochemical properties of Mm(NiCoMnAl)5was investigated. It was found that a little amount of Fe (0.4w%)in Mm revealed unobservable effect on the electrochemical properties of the alloys such as the electrochemical capacity,discharging voltage plateau and cycle life,and when the amount of Fe in Mm attained 0. 4w% ,the activating rate of the alloy slightly decreased. X-ray diffraction analysis showed that the Mm (NiCoMnAl )5consist of single phase with hexagonal CaCu5 -type structure and the lattice parameters did not change when the amount of Fe as an impurity in Mm was not more than 0. 4w% SEM and EDS analyses indicated that there was no difference of the micro - morphologies between the alloys from Mm containing 0. 084w % Fe and 0. 4w% Fe and both the alloys had homogeneous composition,without Fe -rich phase detected in.