Samples which consisted of a Pd over-layer, sputter-deposited FeTi0.9 film, and a Pd plate were studied at 473 to 773K. The H diffusivity was deduced from permeation theory for bilayer composites. The film was amorphous at 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 decreased markedly after crystallization of the film. The calculated H diffusivity in the crystalline material exhibited a small temperature dependence:

D (cm2/s) = 2.84 x 10-6 exp[-19.0(kJ/mol)/RT]

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

M.Amano, K.Nakamura: Transactions of the Japan Institute of Metals, 1988, 29[4], 308-13