Hydrogen storage properties of 2Mg-Fe mixtures processed by hot extrusion: Influence of the extrusion ratio

Hot extrusion processing was employed to produce 2Mg-Fe bulk mixtures for hydrogen storage. 2Mg-Fe powder mixtures were prepared by high-energy ball milling. These mixtures were cold pressed into cylindrical pre-forms, which were then processed by hot extrusion (at 300 °C) to produce bulks. In this work, we analyzed the influence of the extrusion ratio (3/1, 5/1 and 7/1) on the sorption properties of the bulks. The nanometric grain size remained unaltered after all hot extrusion conditions. More porous bulks were produced at an extrusion ratio of 3/1. In the first cycle of hydrogenation, the sample processed at 3/1 absorbed more hydrogen (4 wt% of H) than the precursor powders (3 wt% of H). The results showed that the desorption temperature of bulks were very similar to that of 2Mg-Fe powders, which is good considering the lower surface area of bulks, and that samples with Fe in excess presented lower desorption temperatures. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.