Hydrogen diffusion in amorphous Ni35Ti65studied by NMR

Abstract

The relaxation rates Gamma 1 and Gamma 2 of hydrogen in amorphous Ni35Ti65 have been observed in the temperature range from 100K to 450K at the external fields 0.2 T, 0.8 T and 2.1 T. The temperature and field dependences of the Gamma 1 relaxation rate indicates that the diffusion of hydrogen cannot be described by one thermally activated process but with a gaussian distribution of activation energies with a maximum at Q=0.35 eV, and half-width Delta Q12/=0.16 eV. The pre-exponential factor tau 0=7*10-13 s was found to be of the same order as for crystalline materials in the adiabatic limit.