Abstract

G. URRETAVIZCAYA; G. GARCIA; D. SERAFINI  and  G. MEYER. Mg-Ni alloys for hydrogen storage obtained by ball milling. Lat. Am. appl. res. [online]. 2002, vol.32, n.4, pp.289-294. ISSN 0327-0793.

The effect of the atmosphere and milling time on the structural, morphological and hydrogen reactivity properties of the mechanically alloyed Mg-Ni system is studied. Nanocrystalline Mg₂Ni formed by ball milling in argon exhibits a higher thermal stability than the metals amorphized by milling during shorter times. It is shown that the initially fast hydrogen absorption kinetics of Mg₂Ni at 250°C strongly depends on the crystallinity degree. When the Mg-Ni mixture is mechanically alloyed under hydrogen atmosphere, MgH₂ is formed at first and Mg₂NiH₄ is obtained later. Samples prepared in argon show a higher hydrogen absorption capacity than those obtained in hydrogen.

Keywords : Mg-Ni; Metallic hydrides; Mechanical alloying; Hydrogen absorption.

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