The Role of  H 2 S  in the Corrosion and Hydrogen Embrittlement of Steel

Abstract

Hydrogen permeation in a high strength ferritic steel was shown to depend on the passivity of the surface and the presence of HfS. In the case where HfS is not present, an oxide on the surface of the steel reduced the kinetics of the proton discharge rate and, even more so, the kinetics of the molecular hydrogen evolution rate. Thus, a high percentage of hydrogen permeated the steel. After the oxide was removed, there was an increased proton discharge rate and an equally increased hydrogen evolution rate. thus resulting in very low percentage of hydrogen permeation. When H~S was present, the hydrogen discharge reaction remained high but the recombination reaction was suppressed so the percent of permeation was very high. Thus, HfS plays a multiple role in increasing hydrogen permeation of passivated steel in slightly acidic environments. It increases the rates of iron corrosion and proton discharge and poisons the hydrogen evolution react'ion on the depassivated surface, thereby permitting a large fraction of hydrogen atoms to enter the metal.

Effects of Pollutants and Micro-Organisms on the Absorption of Electrolytic Hydrogen in Iron

“…In addition to their catalytic effect in enhancing the hydrogen evolution and absorption reactions on iron, S 2 0 3 2 ", S0 3 2 " and S are thermodynamically unstable and, therefore, tend to be reduced on the metal surface to H 2 S. Hydrogen sulfide is well known to enhance hydrogen absorption into metals (1,(61)(62)(63)(64)(65)(66)(67)(68)(69)(70) and also to enhance the HER (71)(72)(73). However, the reduction of these sulfide species involves multi-step reactions which makes them kinetically unfavorable.…”

Corrosion in the Oil and Gas Industry: An Increasing Challenge for Materials

“…30,31 Although many explanations have been proposed to account for these effects, the detailed mechanism of the action of H 2 S is not yet fully understood. [32][33][34][35] Fig. 2.…”

L'hydrogène dans les matériaux métalliques en relation avec les interactions plasticité-environnement

“…Elle dépend de différents paramètres : nature de l'électrolyte [20], nature et état structural du métal [21,22], conditions de polarisation, . .…”