HYDROGEN DIFFUSION IN NANOCRYSTALLINE PD BY MEANS OF QUASI-ELASTIC NEUTRON-SCATTERING

Hydrogen Diffusion in nanocrystalline Palladium has been investigated by means of quasielastic neutron scattering (QENS) in the temperature range 220-300K within the alpha-phase. The QENS -results reveal broad and narrow line widths with the first ones being significantly broader than those obtained from the coarse grained PdH reference sample indi cating the presence of a fast diffusion process within the grain bound aries. The narrow line width seems to emerge from the diffusion within the nanocrystalline grains. A large elastic contribution to the spect ra reveals hints on hydrogen traps due to internal surfaces and defect s. For comparison of effects emerging from the preparation process sam ples have been investigated obtained from different preparation techni ques, i.e. pulsed electrodeposition (FED) and inert gas condensation ( IGC). (C) 1997 Acta Metallurgica Inc.