MgAl alloy synthesis, characterization and its use in hydrogen storage

Abstract

The synthesis and characterization of intermetallic MgAl in two stoichiometric relations, Mg25Al and Mg50Al, and their possible use in hydrogen storage are presented. The intermetallic was prepared by thermal induction in an argon atmosphere. The obtained ingot was submitted to a thermal homogenization treatment at 573 K for 72 h. The particle size diminished with a high energy mill type spex, for which the milling time was 30 and 60 min. The material was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Hydrogenation tests were carried out in a micro-reactor with varying pressure, temperature and reaction time. The material was analyzed with a thermogravimetric system before and after the hydrogenation process. The results indicate that the intermetallic phase range with the mill process did not change with the times used. Because of this, smaller particle sizes of less than a micron were obtained just as scanning electronic microscopy analyses demonstrated. X-ray diffraction showed that phase change does not exist in the intermetallic structure after one hour of milling time. The first results obtained by the thermogravimetric system of the hydrogen quantity absorbed in this material report 3% weight approximately under the experimental conditions of mainly pressure and temperature.