Synthesis and hydriding/dehydriding properties of amorphous Mg₂Ni_1.9M_0.1 alloys mechanically alloyed from Mg₂Ni_0.9M_0.1 (M = none, Ni, Ca, La, Y, Al, Si, Cu and Mn) and Ni powder

Amorphous Mg₂Ni_1.9M_0.1 (M = none, Ni, Ca, La, Y, Al, Si, Cu and Mn) alloys were prepared by mechanical alloying of pseudo-binary Mg₂Ni_0.9M_0.1 intermetallic compounds and Ni powder. The crystal structures, thermal stabilities and hydriding/dehydriding properties of those alloys were characterized by powder X-ray diffraction, thermal analysis and conventional measurement of pressure composition isotherms. In spite of the difference in M element, all specimens formed amorphous structures by mechanical alloying. Owing to the substitution of Ca the amount of desorbed hydrogen increased from 1.8 mass% for M = none to 2.1 mass% for M = Ca by measurement of thermogravimetry. The dehydriding reactions occurred at temperatures below about 400 K in both alloys.