COOPERATIVE HYDRIDING PROPERTIES IN A NANOSTRUCTURED MG2NI-H SYSTEM

A nanostructured Mg2Ni-H system was prepared by reactive mechanical gr inding (RMG) of Mg2Ni under a H-2 gas pressure of 1 MPa during various time periods from 5 to 4800 min. The structural and hydriding propert ies of the products obtained were examined by X-ray diffraction, therm al analysis, SEM and TEM. The experimental results showed the existenc e of cooperative dehydriding phenomena in intra- and inter-grain regio ns which have about the same volume fractions. Dehydrogenation from di storted inter-grain regions in nanostructured Mg2Ni-H prepared by RMG for 60 min occurs at the same temperature as hydrogen leaves the intra -grain region of crystalline Mg2NiH0.3. Elastic interactions in nanost ructured materials are important for the understanding of such coopera tive dehydriding phenomena.