Catalytic effect of additives on the hydrogen absorption properties of nano-crystalline MgH2 (X) composites

Hydrogen sorption properties of MgH2-X nanocomposite powders (X=V, Nb, Ti, TiCN) are conditioned by the milling step. The respective roles of the additives and the milling time have been dissociated. The study reveals details not only on the hydrogen sorption process but also on the particle size reduction, distribution and agglomeration, that depend on the nature of the additives. In addition to the effect related to the extra-elements, the milling time has to be optimised to lead to the best particles size reduction without any agglomeration of the grains. (C) 2003 Elsevier B.V. All rights reserved.