Hydrogen absorption properties of amorphous and crystalline La-Ni-B melt-spun ribbons

The possibility of formation of amorphous phase in La-Ni-B system by melt-spun technique has been investigated. It is found that the amorphous phase was formed in a relatively wide compositional range and composition forming amorphous phase nearest LaNi5 compound is LaNi6.4B1.2. The PCT curves of the amorphous ribbons neither have plateau pressure nor almost absorb hydrogen. In addition LaNi6.4B1.2 ribbons start to absorb hydrogens after crystallizing at 1073K. The amount of absorbed hydrogen is about 0.7mass% at 2.0MPa, which is almost half of that of the LaNi5 compound. However, after 30 hydride-dehydride cycle rest, crystallized LaNi6.4B1.2 ribbons show less degradation in comparison with LaNi5 alloys.