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

作者：Fang, Zhikun; Wang, Hui^*; Liu, Jiangwen; Ouyang, Liuzhang; Zhu, Min

来源：JOURNAL OF RARE EARTHS, 2022, 40(3): 467-472.

DOI：10.1016/j.jre.2020.11.015

• Hydrogen storage alloys
• YFe3
• Alloying
• Rare earths
• Thermodynamic

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 Y1.1-yScyFe3 (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 Y0.77Sc0.33Fe3 delivers a decomposition enthalpy change of 33.54 kJ/mol and a lowest dehydrogenation temperature of 135 degrees C, in comparison with 38.99 kJ/mol and 165 degrees C for the alloy Y1.1Fe3. The Zr substitution causes a similar thermodynamic destabilization effect, but the composition and microstructure of Y-Zr-Fe alloys need to be further optimized.