NANOCRYSTALLINE METALS AND OXIDES .1. PULSED ELECTRODEPOSITION

Three preparation routes are presented which, in a simple and cheap wa y, allow to produce rather large amounts of nanocrystalline solids wit h controlled particle sizes and narrow particle size distributions: th e pulsed electrodeposition for nanocrystalline metals and alloys (this contribution), and the precipitation in microemulsions of nanocrystal line metal fluorides as well as the sol-gel type hydrolysis in microem ulsions for nanocrystalline metal oxides (next contribution). By means of pulsed electrodeposition we have prepared n-Pd, n-Cu, n-Ni, n-Co a nd n-Fe as well as n-Ni-Cu and n-Ni-Fe alloys. The particle sizes are analysed preferentially using scattering methods; further characterisa tions concern chemical analyses and density or porosity measurements, respectively. The thermal stability is remarkable; grain growth is not detectable below 150 degrees C.As an example of a particular physical property we present the very fast hydrogen diffusion in nanocrystalli ne Pd as investigated by means of quasielastic neutron scattering, an experimental technique which requires large amounts of sample.