Synthesis of the (Sr,Ca)2AlH7 hydride

The hydride (Sr,Ca)2AlH7 was synthesized by ball milling of the (Sr1−xCax)2Al (x = 0.1, 0.2 and 0.3) alloy consisting of (Sr,Ca)8Al7 and (Sr,Ca) under a hydrogen pressure of 0.6 MPa and subsequently hydriding under a hydrogen pressure of 5 MPa. It was found that the yield of (Sr,Ca)2AlH7 decreased with the increase of Ca content. For increasing the yield, it is necessary to moderately raise the hydrogenation temperature to some extent. Furthermore, extra adding a small amount of Al in the starting alloys is beneficial to the further increase of yield.