Abstract
Hydrogen permeability and diffusivity of pure Fe, pure Ni and Fe–Ni alloys were determined using the gaseous permeation method in the temperature range from 473 to 1073 K under the hydrogen pressure ranging from 0.01 to 0.1 MPa. Values of both permeability and diffusivity for pure Ni and those of permeability for pure Fe agreed well with literature values. Arrhenius plot of diffusivity for pure Fe showed a good linear relationship to temperatures as low as 473 K. Both permeability and diffusivity for Fe–Ni alloys with less than 30 at%Ni showed a sudden change due to the martensitic transformation (bcc\
ightleftarrowsfcc) giving two distinct temperature dependences. The activation energies for both permeation and diffusion in fcc phase were larger than those in bcc phase. Variation of permeability and diffusivity with alloy composition was complicated, but, most of the values were found in the range between those for pure Fe and pure Ni. The rusults that the variation of permeability was similar to that of lattice parameter or that of magnetic moment of the Fe–Ni alloys suggest the existance of some correlations between permeation phenomena and electric properties of the alloys.
