Characterization of hydride forming intermetallics applied to thermal compression of hydrogen

P. LACOURT; B.A. TALAGAÑIS; M.R ESQUIVEL; G.MEYER

Ciudad de Buenos Aires

Congreso; Congreso SAM/CONAMET 2009; 2009

Asociación Argentina de Materiales

Powder Ni, Cu and Ce0,52La0,25Nd0,17Pr0,06 were mechanically alloyed in a low energy mill up to completion stage. A mixture of two intermetallics, Cu0,35Ni0,65 and Ce0,52La0,25Nd0,17Pr0,06Ni4,70Cu0,30, was obtained. The product was characterized by Scanning Electron microscopy (SEM), X-ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Differential Scanning Calorimetry (DSC). Chemical composition of the mixture was verified by a combination of EDS, an application of Vegard´s Law to the experimental diffraction patterns and Rietveld refinements. Mass quantification of the mixture was done by using this last method. The structural properties of the Cu0,35Ni065 and Ce0,52La0,25Nd0,17Pr0,06Ni4,70Cu0,30 mixture were improved by annealing at 600 °C during 24 h under Argon atmosphere. No thermal evolution indicating either the recrystallization or the grain growth of the as-milled Ce0,52La0,25Nd0,17Pr0,06Ni4,70Cu0,30 was found by DSC. Nevertheless, the recrystallization is observed by XRD. The hydrogen sorption properties of the mixture of intermetallics were analyzed by volumetry. The hydrogen pressure-composition-isotherms (PCI´s) were measured between 0 and 70 °C. The AB5-based absorbed hydrogen at a maximum pressure of 4300 kPa at 0 °C and desorbed at a minimum pressure of 6000 kPa at 70 °C. From these results, a hydrogen compression scheme of 1,40 is reached. The structural properties of the Cu0,35Ni065 and Ce0,52La0,25Nd0,17Pr0,06Ni4,70Cu0,30 mixture were improved by annealing at 600 °C during 24 h under Argon atmosphere. No thermal evolution indicating either the recrystallization or the grain growth of the as-milled Ce0,52La0,25Nd0,17Pr0,06Ni4,70Cu0,30 was found by DSC. Nevertheless, the recrystallization is observed by XRD. The hydrogen sorption properties of the mixture of intermetallics were analyzed by volumetry. The hydrogen pressure-composition-isotherms (PCI´s) were measured between 0 and 70 °C. The AB5-based absorbed hydrogen at a maximum pressure of 4300 kPa at 0 °C and desorbed at a minimum pressure of 6000 kPa at 70 °C. From these results, a hydrogen compression scheme of 1,40 is reached.