过化学计量比无钴合金Ml(Ni_(0.82)Mn_(0.07)Al_(0.06)Fe_(0.05))_(5.4)的晶体结构和电化学性能

Microstructure and Electrochemical Properties of Co-free Over-stoichiometric Alloys Ml(NiMnAlFe)_(5.4)

摘要:

详细研究了过化学计量比无钴合金 Ml(Ni0 .82 Mn0 .0 7Al0 .0 6 Fe0 .0 5) 5.4 在常规熔铸、快速凝固、退火处理不同制备条件下的组织结构和电化学性能。X射线衍射 (XRD)分析表明 ,常规熔铸合金由 Ca Cu5型主相加少量的第二相(Al Ni3)组成 ,而快速凝固合金的第二相析出得到一定程度的抑制 ,常规熔铸合金经 10 0 0℃退火处理后 ,部分第二相溶解消失。电化学测试表明 ,与常规熔铸合金相比 ,快速凝固和退火处理均大大提高了合金的电化学循环稳定性 ,但活化性能和高倍率放电性能稍有下降。快速凝固合金的电化学容量有所提高 ,而退火合金的放电容量与常规熔铸合金的基本相当

Abstract:

The Co free over stoichiometric alloy Ml (NiMnAlFe) 5.4 were prepared using conventional cast, rapid solidification (melt spinning) and annealing processes. The microstructure and electrochemical properties of these alloys were investigated comparatively. XRD analyses show that three kinds of the alloys are all composed of main phase with CaCu 5 structure and the second phase (AlNi 3), but the amount of the second phase in the melt spinning alloy is less, and the second phase in annealed alloy disappeared. The electrochemical analyses show that the melt spun and annealed alloys all have better cycling stability than that of conventional cast alloy, but their discharge capacity and high rate dischargeability are little lower than that of conventional cast alloy.