Hydrogen desorption properties of the quaternary alloy system Mg_2-XM1_XNi_1-YM2_Y

The effect of substitutions for Mg and Ni in the Mg₂Ni alloy on hydrogenation properties was studied. In the case of substitution for Mg only, the desorption equilibrium pressure remained constant while the unit cell volume changed. But in the quaternary alloy system obtained from Mg₂Ni by simultaneous substitutions for Mg and Ni, the cell volume correlated with the hydrogen pressure. This is because hydrogen has a tendency to enter interstitial sites in the quaternary Mg₂Ni based alloys, the same behavior as found in the case of AB₅. Therefore, the hydrogenation properties of Mg₂Ni will be improved by tailoring the effect of cell volume using suitable substitution elements.