On the mechanism of hydrogen permeation in iron in alkaline medium

Enhanced hydrogen entry into iron from 0.1M NaOH at definite potentials

“…On the contrary, a prolonged cathodic polarization of iron in 0.1 M NaOH resulted in a growth of oxide deposits on the surface [18,19]. The presence of a 0.5-1 nm thick film of iron oxy-hydroxide was postulated by Brass and Collet-Lacoste [20] in the model for the hydrogen entry into iron from alkaline medium (0.10 M NaOH).…”

“…It has been reported that monolayers of O on transition metals strongly reduce the adsorption and desorption rates of hydrogen [21], and passive films impede absorption of hydrogen [20,22]. On the other hand, Fe-O species with Fe of a low valence were suggested to promote hydrogen entry into iron at low cathodic and low anodic polarizations in near-neutral solutions [23] and in NaOH solutions [24,25].…”

Effect of electrodeposition parameters on the hydrogen permeation during Cu–Sn alloy electrodeposition

“…The diffusion of hydrogen can markedly deteriorate various properties of steels, which has attracted the interest of researches [5][6][7][8][9][10][11]. It was proved that the diffused hydrogen would react with the metal atoms to form brittle metal hydride, leading to the failure of structure even under the applied stresses far below the yield strength [5]. The diffused hydrogen may also combined into hydrogen molecules and accumulate in the microvoids which located close to the surface of the material.…”

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

“…However, in pure iron, the lattice diffusion coefficient of hydrogen D Fe , which ranges 7.3 to 9.5 и 10 Ϫ5 cm 2 иs Ϫ1 at 298°K, [34,51] cannot be obtained without palladium coatings. [52] The 3Cr-1Mo-V steel exhibits the smallest D eff value, regardless of the charging condition. In comparison with 2.25Cr-1Mo steel, this small value can be ascribed both to the increase of the Cr content [28] and to the presence of V containing very fine precipitates.…”