Hydrogen Permeation Characteristics of Melt-Spun Ni-Nb-Zr Amorphous Alloy Membranes

We prepared the melt-spun (Ni0.6Nb0.4)100-xZrx(x = 0 to 40 at%) 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, Δ√p. At relatively higher temperature up to 673 K or at relatively higher hydrogen pressure difference, Δ√p up to 550 Pa1/2, the hydrogen flow was more strictly proportional to Δ√p. 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)60Zr40 amorphous alloy in this work due to the embrittlement during the measurement. The maximum hydrogen permeability was 1.3 × 10-8(mol·m-1·s-1·Pa-1/2) at 673 K for the (Ni0.6Nb0.4)70Zr30 amorphous alloy. It is noticed that the hydrogen permeability of the (Ni0.6Nb0.4)70Zr30 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.