Hydrogen isotope diffusivity and solubility in nickel, palladium, and copper

An analysis is presented of diffusion coefficients and solubility of hydrogen isotopes in nickel, palladium, and copper. For describing the vibrational spectrum of solutions a harmonic approximation is used, and it is assumed that localized levels exist connected with oscillations of interstitial atoms. Atom jumps are described basing on absolute rate theory. Experimental data regarding the pre-exponentials in the temperature dependences of solubility, diffusion coefficients, and corresponding isotope effects are consistently described using an estimation model accounting for metal lattice deformation and charge of electron concentration upon dissolution of hydrogen, and assuming a jump mechanism: octa-→tetra-→octahedral interstitials. (author)