Hydrogen storage properties of the mechanically alloyed LaNi5-based materials

Mechanical alloying has been used to synthesize LaNi5-based hydrogen storage alloys. Mechanical milling of the La and Ni powder blend results in the direct formation of nanocrystalline AB(5) phase. Hydrogen storage measurements show that this as-milled LaNi5 compound does not absorb much hydrogen reversibly. Annealing leads. to grain growth, release of microstrain, and to an increase of storage capacity. Substitution of La or Ni by a third element can easily be achieved by mechanical alloying. The structure and hydrogen storage properties of these LaNi5-based alloys prepared by mechanical alloying and annealing show no big difference with those of melt casting alloys. (C) 2001 Elsevier Science B.V. All rights reserved.