Phase equilibria of Ce–Mg–Ni ternary system at 673 K and hydrogen storage properties of selected alloy. (21st January 2016)

• Record Type: Journal Article
• Authors: Wu, Kong-Bao; Luo, Qun; Chen, Shuang-Lin; Gu, Qin-Fen; Chou, Kuo-Chih; Wang, Xun-Li; Li, Qian
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 3(2016)
• Page Start: 1725
• Page End: 1735
• Publication Date: 2016-01-21
• Subjects: Ce–Mg–Ni system -- Phase equilibria -- Thermodynamic property -- Kinetic mechanism -- Phase transformation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.11.068
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The isothermal section of Ce–Mg–Ni ternary system at 673 K was constructed through thermodynamic calculation coupled with experimental verification. Under guidance of the phase diagram in Mg-rich corner, Ce2.92 Mg91.84 Ni5.24 was designed to investigate its hydrogen storage properties. Moreover, the mechanism of α-to-β (α: diluted phase and β: hydride) phase transformation in the Ce2.92 Mg91.84 Ni5.24 –H2 system was elucidated by in situ synchrotron powder X-ray diffraction (SR-PXRD). The alloy showed a good activated ability and displayed two plateaus in the pressure–composition–temperature curves. The kinetic mechanisms of hydriding and dehydriding reactions were analyzed by Chou model. The rate-controlling steps were the diffusion for the initial stage in hydriding reaction and the surface penetration for dehydriding reaction. SR-PXRD patterns indicated that the activated Ce2.92 Mg91.84 Ni5.24 gradually transformed into CeH2.51, (Mg) (with solid solution of H atoms) and Mg2 NiH0.3, finally transformed into CeH2.51, MgH2 and Mg2 NiH4 during the first hydriding process. Graphical abstract: Highlights: Phase equilibria of Ce–Mg–Ni system at 673 K was constructed by CALPHAD method. The hydrogen storage properties of the Ce2.92 Mg91.84 Ni5.24 alloy were studied. The mechanism of α-to-β phase transformation was detected by in situ SR-PXRD.