Corrosion mechanisms in aqueous solutions containing dissolved H2S. Part 1: Characterisation of H2S reduction on a 316L rotating disc electrode

• Published in: Corrosion science Vol. 66; no. 66; pp. 324 - 329
• Main Authors: Kittel, J., Ropital, F., Grosjean, F., Sutter, E.M.M., Tribollet, B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2013; Elsevier
• Subjects: Applied sciences; B. Electrochemical calculation; B. Modelling studies; B. Polarization; C. Acid corrosion; Chemical Sciences; Corrosion; Corrosion environments; Exact sciences and technology; Material chemistry; Metals. Metallurgy; Other; B. Modelling studies; B. Electrochemical calculation; C. Acid corrosion; B. Polarization; Austenitic stainless steel; Corrosion mechanism; Acid corrosion; Hydrogen Sulfides; Rotating disk electrode; Modeling; Rotating electrode; Calculation; Aqueous solution; Stainless steel-316L; C. acid corrosion; B. electrochemical calculation; B. modelling studies
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2012.09.036

► Reduction reactions occurring during steel corrosion by CO2 and H2S are examined. ► H2S enhances the cathodic reactions in water similarly as CO2. ► CO2 produces additional cathodic current of chemical nature (buffer effect). ► On the contrary H2S provides an additional electrochemical reaction. ► The additional current should correspond to the reduction of H2S or HS− to 1/2 H2. This paper compares the cathodic reactions occurring on steel in aqueous solution containing dissolved H2S or CO2. In aqueous solutions containing these weak acids, the rate of the cathodic reaction is enhanced in comparison with strong acid solutions at the same pH. In the case of dissolved CO2, this phenomenon is fully explained by a buffer effect, contributing to the transport of proton at the steel surface. In the case of H2S containing solutions, this chemical mechanism is no more sufficient to explain the cathodic polarization curves. An additional electrochemical reaction is clearly observed, with strong links with H2S concentration.