Microstructure and novel hydrogen storage properties of melt-spun Mg–Ni–Mm alloys

The non-hydrogenated and hydrogenated microstructure and hydrogen storage properties of a melt-spun Mg–10Ni–2Mm (at.%) alloy have been studied. By increasing the solidification rate, the kinetics of the H-absorption/desorption reactions of the melt-spun ribbons was greatly improved, probably due to fast hydrogen diffusion in considerably amounts of nano-sized grains. RS processing resulted in the formation of the high-temperature cubic modification of Mg2NiH4 and the solid solution hydride phase Mg2NiH0.3 due to incomplete hydrogenation of Mg2Ni. A maximum hydrogen storage capacity of 5.1 wt.% H was obtained. The samples that were solidified at the highest solidification rate, displayed the narrowest desorption temperature range (during vacuum TDS) due to a high uniformity of the nano-sized particle distribution.