(1. 北京科技大学物理化学系，北京100083； 2. 清华大学材料科学与工程 系，北京100084)
摘 要: 研究了Sn替代贮氢合金LaNi5和MlNi5(Ml=富镧混合稀土)中部分Ni对合金的结构、吸氢容量和平衡氢压等性能的影响。用X射线衍射进行物相分析，测试了298K，313 K，333 K温度下合金的吸、放氢 p-c-T 曲线。结果表明，MlNi5-xSnx合金(x=0，0.1)为六方晶体结构的单相组织。以Sn部分取代Ni，使平台压力降低，吸、放氢滞后减小，而吸氢能力降低很小。利用电负性、电子浓度及原子尺寸等参数的半经验模型，计算的ΔH与实验值符合较好，因此，少量Sn替代Ni时，影响合金热力学性质的主要因素是外层电子数的变化。
关键字: 贮氢合金；稀土金属；锡
（1. Department of Physics and chemisty, University of Science and Technology Beijing, Beijing 100083, P.R.China;
2. Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R.China）
Abstract:The effect of partial substitution of tin for nickel in hydrogen storage alloys LaNi5 and MlNi5(Ml=lanthanum-rich mischmetal) on structure, hydrogen content, hydrogen absorption capability and hydrogen equilibrium pressure of those hydrogen storage alloys was investigated. The phase structure was studied by X-ray diffraction analysis . The hydrogen absorption and desorption pressure-composition isotherms were measured under t he temperature of 298 K, 313 K and 333 K. The results indicate that the MlNi5-xSnx(x=0～0.1 ) alloys have a single phase and hexagonal structure. The partial substitution of tin for nickel in MlNi5 results in low hydrogen equilibrium pressure and hysteresis. There is little decrease in hydrogen capability when a small amount of tin is added.
Key words: hydrogen storage alloys; rare earth; tin
