Hydrogen Diffusion in a Model Molybdenum Containing Steel: a Comparison between Hydrogen Ingress Promoted by H2S or Cathodic Charging

Abstract In contact with a sour solution, the absorption and the diffusion of hydrogen in a model molybdenum containing steel with a quench and temper microstructure was characterized with the electrochemical permeation technique. The implementation of a subsequent decay transient to the build-up allowed the determination of the amounts of interstitial and trapped hydrogen in the steel membrane. Similar experiments were conducted with the same material cathodically charged in hydrogen from a concentrated sulfuric acid solution. Comparison of the data resulting from both approaches reveals a good correlation. It suggests the usefulness of these techniques to study the hydrogen diffusion and segregation in steel membrane even if surface modifications occur during the hydrogen charging.