Destabilizing effect of Al substitution on hydrogen absorption in Zr(AlxV1−x)2

The effect of Al substitution on the hydrogen absorption in Zr(AlxV1−x)2, x = 0, 0.1, 0.2, 0.5, has been examined at the pressure range 10−4–1000 Torr for temperatures between 400 and 700 °C. The increasing content of Al destabilizes the bulk hydrogen absorption across the pseudobinary Zr(AlxV1−x)2 intermetallic compounds. This behavior is opposed to the Al effect in other well-known hydrogen absorbing systems like LaAlxNi5−x, Zr(AlxCo1−x)2, Zr(AlxFe1−x)2. This difference is discussed in view of the various factors that determine hydrogen absorption in intermetallic systems.

► Al substitution destabilizes the hydrides in the Zr(AlxV1−x)2 system, 0 ≤ x ≤ 0.5. ► The Zr(AlxV1−x)2 hydride stabilities obey the rule of reverse stability. ► The Zr(AlxV1−x)2 hydride stabilities follow the change of Al and V hydrogen affinities. ► The lattice volumes just slightly change across the Zr(AlxV1−x)2 system.