中文摘要：

用熔体快淬技术制备了La0.75Mg0.25Ni3.5Co0.2合金。采用扫描电镜与X射线衍射仪分析了合金的显微组织结构，并采用电化学法测试了合金电极的电化学性能。结果表明，快淬态合金为多相结构，合金的XRD谱中主衍射峰半高宽和微观应变增大，晶粒明显细化，柱状晶微区较大。随着淬速的提高，合金的放电容量降低，放电平台中值电位以及开路电位正移，合金的循环稳定性提高。

英文摘要：

Mg0.25Ni3.5Co0.2 alloy was prepared by melt rapid quenching technology. The microstructure of the alloy was analyzed by SEM and XRD, and its electrochemical performance was tested with electrochemical method. The results show that the quenched alloy has multiphase structure,increased main diffraction peak FWHM and micro-strain, obviously refined grains and larger area of columnar crystal zone. With the increase of quenching rate, discharge capacity of the alloy decreases, medium potential of discharge plateau and open-circuit potential positively shift, and cycling stability is enhanced.