HRTEM Study of Nanostructures in Hydrogen-Absorbing Mg-Ni and Mg-Ni-La Alloys Prepared by Melt-Spinning

摘要

The structure of melt-spun and crystallized Mg-10%Ni and Mg-10%Ni-5%La alloys is studied using HRTEM, coupled with ED and EELS techniques, for specimens subjected to hydrogenation and dehydrogenation. The presence of nano-sized (5-10nm) Mg_2Ni grains dispersed in the matrix of Mg nano-grains is observed before hydrogenation. This structure is almost preserved after hydrogenation and dehydrogenation at 300℃. In the hydrogenated specimen, nanoboundaries lying between MgH_2 and Mg_2NiH_4 nano-grains are observed. They appear to provide main routes for the hydrogen transport in these nanostructured materials.