Hydrogenation of Eutectic Alloy in the Mg–Al System

To optimize hydrogenation conditions for microcrystalline eutectic alloy with the composition Mg69Al31 (a mixture of magnesium with the γ-Mg17Al12 intermetallic compound), we have studied reactions of 200-μm powder of the alloy with hydrogen and ammonia in the temperature range 100–500°C. We have determined the composition of the reaction products and demonstrated that the use of hydrogen allows magnesium dihydride to be obtained at a temperature of 420°C and that the hydrogenation of the eutectic alloy with ammonia as a hydriding agent leads to the formation of MgH2 and a solid solution of hydrogen in the Mg17Al12 intermetallic compound at 250°C. The hydrogen content in the reaction products obtained by hydrogenation with hydrogen is 4.4 wt %.