An investigation of the microstructure and hydrogenation/dehydrogenation properties of ball-milled CeMg ₁₂ alloys with Ni powders

Abstract

CeMg ₁₂ + 100 wt.% Ni composite hydrogen storage alloys were prepared using ball-milling. The phase structure, morphologies, and hydrogen absorption and desorption kinetics of these alloys were systematically investigated. The results show that the milled CeMg ₁₂ + 100 wt.% Ni alloys consisted of Mg ₂Ni and Ni phase with nanocrystalline and amorphous structures. Additionally, the volume fractions of the phase increased with prolonged ball-milling times, which improved the hydrogenation rates and the hydrogen storage capacities of the alloy samples. However, the dehydrogenation kinetics of the alloy samples were also impaired by the increased milling times. The poor dehydriding kinetics of the alloy samples milled for 80 h and 100 h were primarily attributed to grain size effects.