Diffusion Coefficient of Hydrogen in Iron without Trapping by Dislocations and Impurities

Abstract

In order to obtain the diffusion coefficient of hydrogen in iron free from trapping by dislocations and impurities, electrochemical permeation measurements have been done using high purity iron (99.99 mass% Fe), pure iron (99.99 mass% Fe, high substitutional and low interstitial impurity contents), pure iron (99.94 mass% Fe), and commercially pure iron (99.83 mass% Fe) between 278 and 318 K. Though these specimens, in which the dislocation densities are (0.6-4.4)×10 11 m -2 , have been annealed at high temperatures (973-1223 K), the diffusion coefficients measured (D a ) are influenced by the trapping effect of dislocations