Vol.10・11 - 1 Review
Hydrogen in Refractory Metals
Shotaro MOROZUMI (Guest Professor)
Hydrogen Isotope Research Center, Toyama University,Gofuku 3190, Toyama 930, JAPAN
(Received July 31, 1991; accepted October 31, 1991)
Abstract
Dissolution, diffusion, and permeation of hydrogen
in refractory metals, namely the Va and Ⅵa group metals, are briefly reviewed.
Heats of solution for hydrogen in the Va group metals with electron density,
e/a, of 5 are about -8 kcal/mol, while those in the Ⅵa group metals with
e/a of 6 are about +10 kcal/mol. Heats of solution for hydrogen in the
metals, alloyed with other metals to vary the values of e/a ratio, change
along a smoothly curved tie line between 4 and 6 of e/a with minor deviations,
some of which can be explained in terms of density states at Fermi surface,
atomic size effect, and/or lattice distortion. Activation energies for
the diffusion and permeation are considered from similar points of view.
Isotope effect and hydrogen embrittlement are also described.