Sn对稀土系贮氢合金性能的影响

Effect of Sn on rare earth base hydrogen storage alloys

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 2 98K ,31 3K ,333K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。

The effect of partial substitution of tin for nickel in hydrogen storage alloys LaNi 5 and MlNi 5 (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 the temperature of 298 K, 313 K and 333 K. The results indicate that the MlNi 5 x Sn x ( x =0～0.1) alloys have a single phase and hexagonal structure. The partial substitution of tin for nickel in MlNi 5 results in low hydrogen equilibrium pressure and hysteresis.There is little decrease in hydrogen capability when a small amount of tin is added.