Structural and hydrogenation properties of an 80 wt% TiCr1.1V0.9–20 wt% LaNi5 composite material

In order to monitor the hydrogenation/dehydrogenation characteristics of the bcc TiCr1.1V0.9 compound, two composites samples containing 20 wt% of LaNi5 were synthesized by melting and by mechanical alloying. The X-ray diffraction (XRD) analysis reveals that the melted material crystallizes with two bcc phases after a complete dissolution of the hexagonal LaNi5. Besides, the mechanical alloying (MA) procedure does not yield any modification of composition of the mixed phases. Therefore, a line broadening due to the particle size refinement is observed. For the melted alloy, the pressure-composition measurements carried out at 303 K reveal a decrease of both the maximum hydrogen capacity and the reversible hydrogen amount. Conversely after a MA treatment, hydrogenation/dehydrogenation properties are enhanced, even if a reduction of the maximum hydrogen capacity is pointed out. In both cases of alloying, the equilibrium plateau pressure is reduced reference to the starting bcc TiCr1.1V0.9 compound.