Interrelation between Hydrogen Desorption Kinetics and Structure of (Mg2Ni)Hx and Hydrogenated Eutectic(Mg/Mg2Ni)Hy
Mg-rich alloys of the binary system Mg-Ni are prospective hydrogen-storage materials. In the present study, desorption characteristics of hydrided Mg2Ni intermetalic and hydrided Mg/Mg2Ni eutectic mixture were investigated. Structure of experimental materials during the hydrogenation was observed by SEM. Three modifications of (Mg2Ni)Hx (x ~ 4) were prepared differing in the ratio of two low-temperature phases f = LT2/LT1: with (i) f >1, (ii) f ~ 1 and with (iii) f <1. Evolution of the ratio f during hydrogen desorption was checked by XRD. It was found that the micro-twinned phase LT2 is not desirable in hydrogen-storage materials containing Mg2Ni intermetallic. Diffusion coefficient of hydrogen in LT2 is about 20 times lower than in LT1.
A. Agüero, J.M. Albella, M.P. Hierro, J. Phillibert and F.J. Pérez Trujillo
J. Cermak and L. Kral, "Interrelation between Hydrogen Desorption Kinetics and Structure of (Mg2Ni)Hx and Hydrogenated Eutectic(Mg/Mg2Ni)Hy", Defect and Diffusion Forum, Vols. 289-292, pp. 167-174, 2009