Hydrogen isotope electromigration and impurity effect in vanadium

The effective charge of protium and tritium in the α-phase of vanadium has been measured by means of a stationary state electromigration experiment in a temperature region from 323 to 523 K. The obtained results have shown a definite mass dependence such as Z*(T)>Z*(H) in a lower temperature region and a tendency that the effective charge of H and T approaches a same value in a higher temperature region. By comparing this result with the data for protium and deuterium previously reported by other investigators, we have 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 been discussed by decomposing the effective charge into the direct and wind charges. The trapping effect due to a small zirconium impurity in the investigated vanadium specimen on the electromigration of hydrogen isotopes has been also examined and the trapping model has been discussed.