Formation of Mg(OH) 2 in Mg–Ni–Fe 2O 3 alloys prepared using reactive mechanical grinding

Abstract

Nickel and purchased Fe 2O 3 or Fe 2O 3 synthesized by spray conversion were added to Mg via reactive mechanical grinding (mechanical grinding in H 2). Samples with compositions of 71.5 wt%Mg–23.5 wt%Ni–5 wt%Fe 2O 3 (purchased) and 71.5 wt%Mg–23.5 wt%Ni–5 wt%Fe 2O 3 (synthesized by spray conversion) were prepared, and the phase changes in the samples were examined using X-ray diffraction analysis following hydriding–dehydriding cycling, as well as following reactive mechanical grinding. Both samples contained an Mg(OH) 2 phase after hydriding–dehydriding cycling, as well as after reactive mechanical grinding. To the best of our knowledge, the formation of Mg(OH) 2 phase is not reported in Mg-Ni-Fe 2O 3 system hydrogen storage materials.