Hydriding combustion synthesis of Mg2NiH4 from powder mixture

This paper describes a direct production process of pure Mg2NiH4 based on hydriding combustion synthesis in a laboratory scale. In the experiments, a raw material was differently prepared, powder compact of magnesium and nickel mixture at different press pressures and the mixture powder of the metals without pressing, for optimizing operating conditions. Then, they were heated at controlled temperature/pressure conditions. The effect of a raw material conditions on purity of the product was mainly examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Interestingly, the XRD results indicated that pure Mg2NiH4 was simply obtained not only from the compressed cylinders, but also from the powder. Moreover, the SEM observations showed that the compressed sample and the powder one are clearly different appearance although showing identical XRD patterns. These results appealed a possibility of new direct production process of Mg2NiH4 from a powder mixture at low hydrogen pressure, offering many benefits of simple pretreatment, simple equipment, short operating time, high quality product and energy saving.