A study of absorption processes of hydrogen isotopes in some transition metals by LiOD plus LiOH mixture electrolysis

The concentration depth profiles of protium and deuterium in Ti, Nb and Ni loaded using LiOD + LiOH mixture electrolyte have been measured by means of ERDA and SIMS techniques. The isotope absorption ratios. deuterium/ protiu m. determined by the ERDA measurement are estimated to be /D/H)(Tl) = 0.43 and (D/H)(Nb) = 0.17 while the content in Ni is below the detection limit. The agreement between the values determined by the ERDA and SIMS measuremen ts is reasonably good. Based on the transport-absorption model, the mass ba lance equations have been developed and utilized for the present data analy sis. This model reveals that the isotope absorption ratio for the Nb case i s governed mainly by the Aux of hydrogen ions flowing to the surface of the metal electrode, while for the Ti case the competition between the absorpt ion-conversion process and the recombination process in the electrolysis be comes essentially important for the isotope absorption ratio. (C) 2000 Else vier Science B.V. All rights reserved.