Hydrogenation of Intermetallic Compound Mg17Al12

Abstract

A 200-micron powder of γ-Mg₁₇Al₁₂ was reacted with hydrogen and ammonia at temperatures in the range 20–500°C with the goal to determine optimal hydrogenation parameters for this intermetallic compound as a potential hydrogen storage material. Direct hydriding of the intermetallic compound was found to occur at 390°C, but was accompanied by decomposition to a mixture of magnesium hydride with aluminum containing 4 wt % hydrogen. The hydriding of the intermetallic compound by ammonia was also accompanied by the appearance of magnesium hydride in the reaction product, but at 300°C. The hydrogen capacity of the products of reaction between the intermetallic compound and ammonia at 350°C was 3.9 wt % hydrogen. The product of ammonia treatment of the intermetallic compound Mg₁₇Al₁₂ at 450–500°C was a mixture of aluminum with magnesium nitride.