Hydrostatic pressure effects on hydrogen permeation in A514 steel during galvanostatic hydrogen charging

A514 offshore structural steel was exposed to hydrostatic pressure ranging from 0.1 to 40 MPa to examine hydrogen permeation during galvanostatic hydrogen charging. Hydrostatic pressure decreases the energy barrier for hydrogen absorption and desorption, while increasing hydrogen adsorption. These effects are induced by both steady-state current density and the apparent diffusivity slight increase with hydrostatic pressure. Taking surface effect of hydrogen permeation into account, the intrinsic diffusivity of (3.2 +/- 0.04) x 10(-6) cm(2)/s is obtained, which is independent of the hydrostatic pressure. (C) 2016 Elsevier Ltd. All rights reserved.