Steel St3 Corrosion Behavior in Weakly Acidic Media At low Н2S Concentrations

Issue 2(88) 2018
Pages 27-34

L.E. Tsygankova, Tambov State University named after G.R. Derzhavin, (TSU named after G.R. Derzhavin), Tambov, Russian Federation

A.A. Kostyakova, TSU named after G.R. Derzhavin, Tambov, Russian Federation

N. Alshikha, TSU named after G.R. Derzhavin, Tambov, Russian Federation

V.I. Vigdorovich, Tambov State Technical University, Tambov, Russian Federation


Keywords: steel, hydrogen sulphide, protective effect, model stratum water, inhibitor, impedance, polarization

https://doi.org/10.31615/j.corros.prot.2018.88.2-4

 

The influence of low concentrations of Н2S (25…200 mg /L ) on the corrosion rate of St3 steel in the model stratum water was studied by gravimetric, electrochemical methods and the method of linear polarization resistance from ten-day experiments. In an imitate with pH = 6, an increase in the concentration of Н2S in the range 25…100 mg /L causes an increase in the protective effect
of Н2S. At 200 mg /L Н2S, the corrosion rate rises, but remains lower than in the solution without Н2S. The introduction of an organic inhibitor in solutions with these additives of Н2S enhances the protective effect. Electron microscopy was used to characterize the state of the metal surface after corrosion. In an imitate with a lower pH (3.6), only 25 mg /L of Н2S causes a decrease in the corrosion rate of the steel.