Electrochemical Corrosion of Ultra-high Strength Carbon Steel in Alkaline Brines Containing Hydrogen Sulfide. (10th September 2016)

• Record Type: Journal Article
• Authors: Feng, Ruishu; Beck, Justin; Ziomek-Moroz, Margaret; Lvov, Serguei N.
• Is Part Of: Electrochimica acta. Volume 212(2016)
• Page Start: 998
• Page End: 1009
• Publication Date: 2016-09-10
• Subjects: Electrochemical corrosion -- Ultra-high strength carbon steel -- Hydrogen sulfide -- Alkaline corrosion -- Corrosion product analysis; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.07.070
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Anodic reaction mechanisms of Fe with HS − (aq), HCO3 − (aq), and OH − (aq) were discussed. High corrosion rate (CR) at pH 10.7 correlated with a high HS − (aq) ratio. Both accelerating and inhibiting effects of H2 S on CR were observed. Corrosion products changed from iron carbonate and sulfide to oxide as pH increased. Sulfur was detected mostly in the inner layer of corrosion products at pH 7.9. Abstract: Electrochemical corrosion of ultra-high strength carbon steel UD-165 was investigated using in-situ electrochemical techniques in H2 S-containing alkaline brines (5 wt% NaCl; pH 7.9, 10.7, and 12.4) with four H2 S partial pressures ( p H2S ) from 0 to 69 kPa at 85 °C. The effects of pH and p H2S were studied in terms of corrosion rate (CR), reaction mechanism, and corrosion products considering the Fe dissolution reactions with HCO3 − (aq), OH − (aq), and HS − (aq). While CR generally decreased at higher pH and increased at higher p H2S, both accelerating and inhibiting effects of H2 S on CR were observed. High CR at pH 10.7 correlated with a high ratio of HS − (aq) to the total concentration of reactive anions. The corrosion products changed from iron carbonate and sulfides to iron oxides as the pH increased. Sulfur was detected mostly in the inner layer of corrosion products at pH 7.9.