INFLUENCE OF MILLING TIME ON THE HYDRIDING PROPERTIES OF AMORPHOUS MgNi ALLOYS

Amorphous Mg50Ni50 alloys were produced by ball milling at two different milling times. The durations of milling were chosen to assure amorphous nature of both synthesized alloys, and at the same time to result in a difference in their amorphous structure (e.g. short range order). Thus, the effect of small difference in the amorphous structure on the hydrogen storage properties of Mg50Ni50 could be studied electrochemically as well as from a hydrogen gas phase by a Sievert's type apparatus. The observed differences in the alloys hydrogen sorption capacity and kinetics could only be attributed to a difference in their amorphous structure. Indeed, although both amorphous, the alloy milled for slightly longer time reveals about 20% higher hydrogen discharge capacity.