Improvement of hydrogen storage properties of melt-spun Mg-Ni-RE alloys by nanocrystallization

The hydrogen absorbing rates and pressure-composition isotherms (PCT) are measured on Mg-Ni and Mg-Ni-RE (RE=La, Nd) alloys which have been amorphized by melt-spinning and crystallized to form nanocrystalline structures. The microstructures of these alloys as examined by X-ray diffraction and transmission electron microscopy consist of mixtures of crystalline grains of major Mg and Mg2Ni phases, together with a minor La2Mg17 or NdMg12 phase, of 50-100 nm in diameter. These nanocrystallized alloys, particularly of the Mg-Ni-RE systems, exhibit excellent hydrogen absorbing kinetics and PCT characteristics in comparison with those of the corresponding as-cast alloys with coarse eutectic structures. (C) 1999 Elsevier Science S.A. All rights reserved.