Hydriding combustion synthesis of Mg2Ni1−xFex hydride

The hydriding combustion synthesis (HCS) of Mg2FeH6 and Mg2Ni1−xFex hydrides was systematically studied by changing the value of x from 0.25 to 1.0. This study aimed at improving the Mg2FeH6 yield in production and examining the effect of the addition of nickel to the hydrogen storage properties of the Mg2FeH6 hydride. In synthesizing metallic hydrides, the raw materials in metallic powders were mechanically activated by a ball mill before the HCS treatment. As a result, the ball-milled 2Mg + Fe recorded as much as 5 mass% in hydrogen storage capacity during the HCS treatment, and the final product successfully indicated a high purity Mg2FeH6. Interestingly, the deformation enthalpies of the Mg2Ni1−xFex hydrides were larger by 10% or more than Mg2NiH4 and Mg2FeH6, taken individually. This was collateral evidence to prove that the HCS of Mg2FeH6 and Mg2Ni1−xFex hydrides with ball milling (BM) produced a new structure of the Mg-Ni-Fe-H system due to the synergy effect.