Hydrogen Absorption Performance of Mechanically Alloyed (Mg<SUB>2</SUB>Ni)<SUB>100&minus;<I>x</I></SUB>Ti<I><SUB>x</SUB></I> Powder

Abstract

The hydrogen storage alloy (Mg 2 Ni) 100Àx Ti x (x ¼ 0, 2.5, 5.0, 7.5 and 10.0 at%) powders were synthesized from elemental powder mixture by mechanical alloying (MA) under an Ar atmosphere. The as-milled powders were examined as a function of titanium addition by X-ray diffraction and synchrotron X-ray absorption near-edge structure (XANES) techniques at various milling time. The hydrogen absorption kinetics of the 15 h as-milled powders were evaluated. The maximum hydrogen absorption content of 15 h as-milled Mg 2 Ni powders can be improved from 3.14 mass% to 3.88 mass% when 5.0 at% of titanium was added. The hydrogenation rate of the Mg 2 Ni powder was also obviously enhanced by introducing the titanium into Mg 2 Ni lattices. More than 20% improvement of hydrogen absorption for Mg 2 Ni intermetallic powders was achieved by adding titanium.