Magnesium-nickel alloy hydride compacts prepared by cylindrical explosion shock compression

High density sintered solid forms of Mg₂Ni hydride and Mg-5wt.%Ni alloy hydride were prepared using the cylindrical explosion shock compression technique. During such treatment, both hydrides lost about 10% of their hydrogen. The colour of the Mg₂NiH_x product was black and uniform, and it was mainly composed of Mg₂NiH₄ and Mg₂Ni, with some MgNi₂ and MgH₂ phases. This material was hard and tough, and rather stable in air. On the contrary, the Mg-5wt.%NiH_x product was greyish in colour, including white stripes and cracks. The sintering process did not proceed in the white part. This material was composed of MgH₂, magnesium metal and some Mg₂Ni phase. The Vickers hardness was 232 and 185 respectively. The porosity was 5.29% and 4.73%, and the hydrogen content was 3.33 wt.% (theoretically 3.73 wt.%) and 6.97 wt.% (7.88 wt.%). The former exhibited metallic conductivity, but the latter was a electrical insulator.