Fabrication of Mg-Ni Hydrogen Absorbing Alloy by Rotation-Cylinder Method and Evaluation of their Hydrogenation Properties

摘要

Mg - 1, 5, 10 mass percent Ni hydrogen absorbing alloys were fabricated by Rotation - Cylinder Method (RCM) and their hydrogenation properties were evaluated by PCI(Pressure-Composition Isotherm) measurement. The microstructure of as-cast Mg-10mass percent Ni alloy is consisted of an island-like hydride forming #alpha#-Mg phase and the eutectic phase. The composition of the eutectic phase is measured about 80 mass percent Mg and 20 mass percent Ni by EPMA. Nickel has a catalytic effect on hydrogen dissociated reaction and the eutectic phase is rich in nickel composition compared with #alpha# phase. So the eutectic phase may act as a hydrogen dissociation site and a channel of difflision of protium. This microstructure may promote the hydrogenation behaviors. The results of the maximum hydrogen storage capacity and reversible capacity of Mg- 10 mass percent Ni alloy were measured about 6.3 mass percent and 4 mass percent at 623K, respectively.