The diffusion coefficients of hydrogen and deuterium in vanadium, niobium, and tantalum by gorsky‐effect measurements

Abstract

Abstract Gorsky‐effect measurements on vanadium‐, niobium‐, and tantalum‐samples loaded with different concentrations (0.2 to 4.3 at%) of hydrogen or deuterium are reported. From the relaxation strength the trace of the dipole‐moment tensor of hydrogen and deuterium was determined and found to be consistent with the lattice parameter changes. From the relaxation time of the Gorsky effect the diffusion coefficients of hydrogen and deuterium in vanadium, niobium, and tantalum were determined in the temperature range from 600 to about 270° K (in the case of hydrogen in niobium down to 120° K). The diffusion coefficients are very large and show only a weak exponential temperature dependence, which moreover decreases for hydrogen in niobium below 300° K. In contrast to classical rate theory the activation energies are isotope dependent whereas the pre‐exponential factors are isotope independent within the experimental errors.