纳米Mg-Ni合金吸/放氢过程的热力学性能研究

Hydrogen Storage Properties of Nanocrystalline Mg₂Ni Based Alloys Prepared by Ball-Milling

摘要: 通过合理改善贮氢材料的结构和表面性能而使新型纳米氢化物材料具有显著的吸氢特性。用机械合金化法制备了Mg-Ni合金粉末，用XRD及TEM等分析表征了球磨过程中的相和微观结构变化，测定了纳米Mg-Ni合金的热力学性能。结果表明，机械合金化能较好地制备Mg-Ni合金粉末，Mg-Ni合金粉末的尺寸在10 nm~20 nm之间；P-C等温线存在明显的坪曲线，坪宽较大。纳米Mg₂Ni合金在523 K的温度下即能吸氢。可逆吸氢容量可达3.5 wt%。总之，纳米Mg-Ni合金有较好的贮氢性能，具有很好的工程应用价值。

Abstract: Nanocrystalline hydrides are new class of material in which outstanding hydrogen sorption may be obtained by proper engineering of the microstructure and surface. In present work, nanocrystalline Mg₂Ni (wt.%) alloy powders with grain size of about 10~20 nm were prepared by high- energy ball milling, and its phase, crystal structure and hydrogen storage properties were investigated via X-ray diffraction analysis (XRD), Transmission electron microscopy (TEM) and Pressure- composition isotherms. Results on the hydrogen storage characteristics of Mg₂Ni are presented. Nanocrystalline Mg₂Ni can readily absorb hydrogen at 523 K. The reversible hydrogen capacity is up to 3.5 wt.%. The nanocrystalline Mg₂Ni alloy is a promising hydrogen storage material.