Mg-Ni alloys for hydrogen storage obtained by ball milling

GUILLERMINA URRETAVIZCAYA; GARCÍA G,; SERAFINI D,; MEYER G,

LATIN AMERICAN APPLIED RESEARCH

Lugar: Bahía Blanca; Año: 2002 vol. 32 p. 289 - 294

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.2Ni 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.