Surface Effects in Simultaneous Ion- and Gas-Driven Hydrogen Isotope Permeation of Nickel

Abstract

Recombination coefficient kR for hydrogen on Ni was evaluated experimentally by measuring the permeation rate of ion-driven deuterium in the temperature range of 573 873 K, with impurities on the specimen surface controlled at nearly the same composition prior to deuterium implantation. Calculation showed that kR's of upstream and downstream-side surface had an apparent activation energy of negative values, but of different values, and that of upstream-side surface increased as much as two orders of magnitude due to the deuterium ion implantation.