Abstract
In the present study, hydrogen-absorbed Mg2Ni intermetallic powders were prepared by mechanical alloying under an Ar atmosphere. Modification of the Mg2Ni powders was attempted by adding silver (0.5, 1.0, 2.5, and 5.0 at%) into starting elemental powder mixtures. The as-milled powders were examined as a function of milling time by X-ray diffraction and synchrotron X-ray absorption techniques. In addition, the hydrogen absorption performance of the 15 h as-milled powders were evaluated. The experimental results show that (Mg2Ni)100−xAgx powders exhibited a mixture of Mg2Ni, magnesium and nickel solid solutions after 15 h of milling treatment. The maximum hydrogen absorption content and reversible hydrogen content of 15 h as-milled Mg2Ni powders was 3.14 and 2.40 mass%, respectively. An improvement of hydrogen absorption properties can be noticed by doping silver, but the less silver addition the better performance. In the present study, (Mg2Ni)99.5Ag0.5 exhibited the best hydrogen absorption properties where the maximum hydrogen absorption content and reversible hydrogen content was increased significantly to 3.93 and 3.14 mass% respectively. More than 25% improvement of hydrogen absorption for Mg2Ni intermetallic powders was achieved by doping silver.
