DEHYDRIDING PROPERTIES OF TERNARY MG2NI1-XZRX HYDRIDES SYNTHESIZED BYBALL-MILLING AND ANNEALING

The ternary hydrogen-storage alloys Mg2Ni1-xZrx (0<x less than or equa l to 0.3) have been successfully synthesized by ball milling followed by annealing. Studies of the synthesis conditions of the ternary alloy s and their dehydriding properties have been carried out. The results show that the ternary Mg2Ni1-xZrx (0<x less than or equal to 0.3) allo ys have the same hexagonal crystal structure as that of Mg2Ni. Compare d with a Mg2Ni alloy, they have a larger specific surface (similar to 1.20 m(2) g(-1)), more promising dehydriding kinetics, lower enthalpy of formation of hydrides than that of Mg2NiH4, and lower decomposition temperatures in an open system. An optimum desorption storage capacit y of about 3.3 wt.% is observed. (C) 1998 Elsevier Science S.A.