Effect of scandium and zirconium alloying on microstructure and gaseous hydrogen storage properties of YFe3

RM₃ compounds (R = rare earth metals, M = transition metals) have rarely been studied for gaseous hydrogen storage applications because of unfavorable thermodynamics. In this work, the hydrogen storage properties of a single-phase YFe₃ alloy were improved by non-stoichiometric composition and alloying with Sc and Zr. Only the Y_1.1–ySc_yFe₃ (y = 0.22, 0.33) alloys consist of a single rhombohedral phase. The Sc substitution for Y leads to the reduction in the unit cell volume of the YFe₃ phase, and thus significantly increases the dehydriding equilibrium pressure and decreases the dehydrogenation temperature. The alloy Y_0.77Sc_0.33Fe₃ delivers a decomposition enthalpy change of 33.54 kJ/mol and a lowest dehydrogenation temperature of 135 °C, in comparison with 38.99 kJ/mol and 165 °C for the alloy Y_1.1Fe₃. The Zr substitution causes a similar thermodynamic destabilization effect, but the composition and microstructure of Y–Zr–Fe alloys need to be further optimized.     

Absorption of hydrogen by sintered intermetallics of the Sc — Ni system

The absorption of hydrogen by the intermetallics Sc₂Ni, ScNi, ScNi₂, Sc₂Ni₇, and ScNi₅ produced by sintering was investigated. Hydrogen absorption isobars at the pressures 0.1 and 3 MPa were obtained. The maximum hydrogen absorption capacity of the compounds was determined. The absorption properties were compared with those of specimens produced by arc melting. Translated from Poroshkovaya Metallurgiya, Nos. 5–6(413), pp. 78–82, May–June, 2000.     

3He的产生对钪氚化物性能影响的第一性原理研究

采用第一性原理对T衰变成3He后,钪氚化物体系的结合能和弹性模量进行了计算.计算结果表明,ScT2中衰变形成的3He将占据体积较小的四面体让隙;3He的产生导致最近邻的T原子与Sc原子的成键作用增强,这可能是氚化物时效后平衡压降低的原因.分析了3He产生后,钪氚化物体系体模量下降的原因.