Samples which consisted of a Pd over-layer, sputter-deposited FeTi0.9 film, and a Pd plate were studied at temperatures of between 473 and 773K. The H diffusivity was deduced via a permeation theory for bi-layer composites. The film was amorphous at temperatures of up to 723K. The effective H diffusion coefficient of the sample was almost equal to that of Pd, and it was therefore impossible to estimate the H diffusion coefficient for the amorphous film. The permeability and diffusivity markedly decreased after crystallization of the film. The calculated H diffusion coefficient in the crystalline material exhibited a small temperature dependence:

D (m2/s) = 2.84 x 10-10 exp[-19.0(kJ/mol)/RT]

This was attributed to short-circuit diffusion through defects such as grain boundaries.

Hydrogen Diffusivity in Sputter-Deposited FeTi Film. M.Amano, K.Nakamura: Transactions of the Japan Institute of Metals, 1988, 29[4], 308-13