The effect of O atoms upon H mobility in membrane samples was studied. In order to remove the O atoms, deoxidizers such as Y, Ti and Zr were added during arc-melting. The permeability and diffusivity of the Pd-plated samples were determined by using gas permeation and time-lag methods at temperatures ranging from 373 to 673K. The samples with added deoxidizer exhibited higher H permeabilities and diffusivities (table 188), than those of deoxidizer-free samples, at temperatures above 473K. At temperatures below 473K, the former samples exhibited H-trapping effects; as did deoxidizer-free samples. It was suggested that solute O atoms decreased the effective area for H permeation. The H-trapping effects at temperatures below 473K were attributed mainly to surface effects.
Effects of Deoxidizer Addition on the Hydrogen Permeation Characteristics of V-Ni Alloy Membranes. M.Komaki, C.Nishimura, M.Amano: Journal of the Japan Institute of Metals, 1992, 56[6], 729-33
Table 188
Diffusion Parameters for H in V-15Ni- Alloys
Alloy | D (m2/s) | E (kJ/mol) |
V-15Ni- | 1.13 x 10-7 | 16.4 |
V-15Ni-0.05at%Ti | 1.32 x 10-7 | 16.1 |
V-15Ni-0.05at% Y | 1.18 x 10-7 | 16.2 |
V-15Ni-0.05at%Zr | 1.28 x 10-7 | 16.8 |
V-15Ni-0.50at%Zr | 1.09 x 10-7 | 33.1 |