Hydrogen permeation characteristics of melt-spun Ni-Nb-Zr amorphous alloy membranes

We prepared the melt-spun (Ni0.6Nb0.4)(100-x) Zr-x (x = 0 to 40at%) and other amorphous alloy membranes and examined the permeation of hydrogen through those alloy membranes. The interatomic spacing in the Ni-Nb-Zr amorphous structure increased with increasing Zr content. The crystallization temperature of the Ni-Nb-Zr amorphous alloys decreased with increasing Zr content. The hydrogen flow increased with an increase of the temperature or the difference in the square-roots of hydrogen pressures across the membrane, Deltarootp. At relatively higher temperature up to 673 K or at relatively higher hydrogen pressure difference, Deltarootp up to 550 Pa-1/2, the hydrogen flow was more strictly proportional to Deltarootp. This indicates that the diffusion of hydrogen through the membrane is a rate-controlling factor for hydrogen permeation. The permeability of the Ni-Nb-Zr amorphous alloys was strongly dependent on alloy compositions and increased with increasing Zr content. However. it was difficult to investigate the hydrogen permeability of the (Ni0.6Nb0.4)(60)Zr-40 amorphous alloy in this work due to the embrittlement during the measurement. The maximum hydrogen permeability was 1.3 x 10(-8) (mol . m(-1) . s(-1) . Pa-1/2) at 673K for the (Ni0.6Nb0.4)(70)Zr-30 amorphous alloy. It is noticed that the hydrogen permeability of the (Ni0.6Nb0.4)(70)Zr-30 amorphous alloy is higher than that of pure Pd metal. These Permeation characteristics indicate the possibility of future practical use of the melt-spun amorphous alloys as a hydrogen permeable membrane.