Hydrogen isotope electromigration and impurity effect in vanadium

The effective charge of protium and tritium in the alpha-phase of vanadium has been measured by means of a stationary state electromigration experimen t in a temperature region from 323 to 523 K. The obtained results have show n a definite mass dependence such as Z*(T)>Z*(H) in a lower temperature reg ion and a tendency that the effective charge of H and T approaches a same v alue in a higher temperature region. By comparing this result with the data for protium and deuterium previously reported by other investigators, we h ave concluded a mass dependence according to the sequence Z*(T)>Z*(D)>Z*(H) in a lower temperature region. The origins of this mass dependence has bee n discussed by decomposing the effective charge into the direct and wind ch arges. The trapping effect due to a small zirconium impurity in the investi gated vanadium specimen on the electromigration of hydrogen isotopes has be en also examined and the trapping model has been discussed. (C) 1999 Elsevi er Science S.A. All rights reserved.