Hydrogen desorption properties of the quaternary alloy system Mg2-xM1xNi1-yM2y

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 AB(5). Therefore, the hydrogenation properties of Mg2Ni will be improved by tailoring the effect of cell volume using suitable substitution elements. (C) 1998 Elsevier Science S.A.