Hydrogen Transport Conditions and Effects in Cathodically Polarized AF1410 Steel

Abstract

Hydrogen permeation of AF1410 steel membranes due to cathodic polarization using the Devanathan and Starchurski double cell (DSDC) with 0.1M H 2 SO 4 + 1 g/L Na 2 HAsO 4 AE7H 2 O, and 0.1M NaOH media in the input and exit cells, respectively, under Galvanostatic conditions depended on the polarization current density, membrane thickness, and surface roughness. For a 0.35-mm-thick membrane, the steady-state hydrogen permeated using increasing polarization currents from 1.00 to 10.00 mA varied correspondingly from 0.6 · 10 -5 (mol H/m 2 s) to 1.03 · 10 -5 mol H/m 2 s, with accompanying transient rates or permeation rates of 1.07 · 10 -4 A/m 2 s to 4.40 · 10 -4 A/m 2 s. With a constant polarization current density of 20 A/m 2 , the steady-state permeated hydrogen was in the range of 1.00 · 10 -5 (mol H/m 2 s) to 3.50 · 10 -5 (mol H/m 2 s), for 0.30-mm and 0.09-mm-thick membranes, respectively. The breakthrough times decreased from 2130 to 300 seconds with decreasing membranes thickness from 0.30 to 0.09 mm. The formation of blisters was observed more on the input side surface than on the exit-side surface and occurred for polarization charging current densities greater than 30.0 A/m 2 . The tendency for blister formation increased with decreasing materialÕs surface roughness. Cracks accompanying blisters tended to form on both the input and exit-side surfaces only with continued charging following the attainment of steady-state permeation, though they were generally lower on the potentiostated exit side. The average effective permeation coefficient of hydrogen was determined to be 2.89 · 10 -12 m 2 /s for membrane thicknesses ranging from 0.09 to 0.30 mm based on the slope method.

Study of the hydrogen diffusion and segregation into Fe–C–Mo martensitic HSLA steel using electrochemical permeation test

“…Figure 8 shows the influence of six charging conditions on the permeation curves. As it is classically reported in the literature [12,31], the breakthrough time is decreasing and the steady-state current is increasing ( Figure 8a, table 2). Moreover, kinetics of diffusion are accelerated under high charging conditions (Figure 8b).…”

Computational analysis of geometrical factors affecting experimental data extracted from hydrogen permeation tests: II – Consequences of trapping and an oxide layer

“…Thus, getting correct hydrogen concentrations C 0eff z C 0 requires several analyses of diffusion coefficients D eff . The sole data on the effects of the membrane thickness for martensitic steels are given with an oxidized exit side [7]. High trapping means an increase in C 0eff .…”

Investigating electrochemical charging conditions equivalent to hydrogen gas exposure of X65 pipeline steel

“…Unsteady surface conditions can be a result of excessive hydrogen bubble formation or changes in local pH, leading to fluctuations in hydrogen flux or detachment of inclusions. [ 26,27,40 ] In addition, the increasing influence of electrochemical recombination at higher cathodic current densities [ 41 ] can reduce the effect of applied current density or potential on the $${p}_{{{\rm{H}}}_{2}}^{\text{eq}}$$. Consequently, it was decided to use a hydrogen recombination poison as the first measure to increase the hydrogen absorption, before changing the applied cathodic potential.…”