Hydrogen Sorption Behavior of Cast Ag-Mg Alloys

Abstract

In this paper, the hydrogen sorption properties of casted Ag-Mg alloys were investigated. The obtained alloys were structurally analyzed by X-ray diffraction (XRD) and observed by scanning electron microscopy (SEM). The study was carried out for four alloys from the two-phase region (Mg) + γ′ (AgMg4) with nominal concentrations of 5 wt. %, 10 wt. %, 15 wt. %, and 20 wt. % Ag, four alloys with nominal compositions equivalent to intermetallic phases: AgMg4, AgMg3, AgMg, and Ag3Mg, one alloy from the two-phase region AgMg + Ag3Mg (Ag60Mg40), and one alloy from the two-phase region AgMg + AgMg3 (Ag40Mg60). The hydrogenation process was performed using a Sievert-type sorption analyzer. The hydride decomposition temperature and kinetic properties of the synthesized hydrides were investigated by differential scanning calorimetry (DSC) coupled with thermogravimetric analysis (TGA). Samples with high magnesium content were found to readily absorb significant amounts of hydrogen, while hydrogen absorption was not observed for samples with silver concentrations higher than 50 at. % (AgMg intermetallic phase).