Hydrogen absorption and desorption properties in
LaMg2Ni compound are presented. Nanostructured phases have been obtained by means of ball milling in order to study the influence of the microstructure in the absorption/desorption properties. The structural and hydriding properties were examined by X-ray diffraction, thermal analysis, hydrogen pressure-composition isotherms and thermal desorption measurements. Ball milling of as-cast alloy gives a significant refinement of the microstructure. Hydrogenation at 170 °C leads to the formation of LaMg2NiH7. Treatments at higher temperatures (250 °C) lead to the formation of LaH2. Thermal desorption up to 710 °C of hydrogenated phases leads again to parent LaMg2Ni phase.