HYDROGEN PERMEATION AND DIFFUSION THROUGH PURE Fe, PURE Ni AND Fe-Ni ALLOYS.

Abstract

Hydrogen permeability and diffusivity were determined from 473 to 1073 K under hydrogen pressure ranging from 0. 01 to 0. 1 MPa. Permeability and diffusivity for Fe-Ni alloys with less than 30 at%Ni showed a sudden change due to a martensitic transformation (bcc reversible reaction fcc) giving two temperature dependences. The activation energies in the fcc phase were larger. The variation of permeability and diffusivity with composition was complicated, but most values were in the range between those for pure Fe and pure Ni.