机械合金化LaNi5-31 %Mg 的结构及性能表征

采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、差热分析(DTA)及电池性能测试仪等方法研究了LaNi₅-31 %Mg 合金的组织形貌、热稳定性能及电化学活化性能等。结果表明:经300 r/ min 球磨250 h 后, 样品中形成了短程有序或无序的镧、镁、镍等非晶及MgNi2 纳米晶(3.4 nm)组织;颗粒形状主要为规则的球形或近球形及少量多角形等, 粒径范围为0.12～8.70 μm 。经763 K 保温35 d, 得到热稳定性较好的具有纳米尺度的Mg₂NiLa, Mg₂Ni, MgNi₂ 三相合金。球磨样品在碱性电解液中首次充放电活化时即达到其最大容量410 mAh/g, 具有较好的室温活化特性和较高的电化学放电容量。

Characterization of Structure and Performer of the Mechanically-alloyed LaNi5-31% Mg Alloy

The microstructure, thermal stability and activation characteristics of the LaNi5-31 %Mg alloy were investigated by XRD, SEM,DTA and battery test apparatus.The results showed that the amorphous structure of La,Mg and Ni and the nanocrystalline structure of MgNi₂ form in the sample after it was ball milled for 250 h at 300 r /min, and their particles were mostly spherical or approximately spherical and a few polygonal, usually 0.12～8.70 μm in particle size.After 45 day of heat preservation at 763 K, the nanoscale Mg₂NiLa-Mg₂Ni-MgNi₂ alloy with a good thermal stability was obtained.The sample reached its maximum discharge capacity(410 mAh g)in alkaline electrolyte during its first charge discharge cycle, indicating that it had better activation characteristics at high electrochemical discharging capacity at ambient temperatures.