(1. 北京科技大學(xué)物理化學(xué)系，北京100083； 2. 清華大學(xué)材料科學(xué)與工程 系，北京100084)
摘 要: 研究了Sn替代貯氫合金LaNi5和MlNi5(Ml=富鑭混合稀土)中部分Ni對合金的結(jié)構(gòu)、吸氫容量和平衡氫壓等性能的影響。用X射線衍射進行物相分析，測試了298K，313 K，333 K溫度下合金的吸、放氫 p-c-T 曲線。結(jié)果表明，MlNi5-xSnx合金(x=0，0.1)為六方晶體結(jié)構(gòu)的單相組織。以Sn部分取代Ni，使平臺壓力降低，吸、放氫滯后減小，而吸氫能力降低很小。利用電負性、電子濃度及原子尺寸等參數(shù)的半經(jīng)驗?zāi)Ｐ停嬎愕摩?EM>H與實驗值符合較好，因此，少量Sn替代Ni時，影響合金熱力學(xué)性質(zhì)的主要因素是外層電子數(shù)的變化。
關(guān)鍵字: 貯氫合金；稀土金屬；錫
（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
