Stability of passive film and pitting susceptibility of 2205 duplex stainless steel in CO2/H2S-containing geothermal environment

• Published in: Corrosion science Vol. 210; p. 110832
• Main Authors: Liu, Huifeng, Hua, Yong, Shi, Shengkai, Lin, Xueqiang, Neville, Anne, Wang, Yong, Sun, Jianbo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2023
• Subjects: 2205 DSS; CO2/H2S; Corrosion product; Geotherm; Passive film; Passive film; 2205 DSS; Corrosion product; Geotherm; CO2/H2S
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2022.110832

Stability of passive film of 2205 DSS in H2S-containing geothermal environments was investigated by immersion test, HTHP electrochemical measurement, surface analysis technique and thermodynamic calculation. The results showed that ip increased with pH2S rising from 0 to 33.1 bar at 150 °C. The presence of H2S prompted the FeS2 and FeS formation in the corrosion product layer, leading to the degradation of the passive film. The adsorption of sulfur species caused the preferential dissolution of the phase boundary, and then the ferrite phase corroded and localized corrosion propagated under S-rich products. [Display omitted] •HTHP electrochemical tests showed enhanced Faradaic reactions due to the presence of H2S.•The adsorption of sulfur species caused the preferential dissolution of the phase boundary.•FeS2 content increased with the rise of pH2S, with FeS as nucleation sites.•Localized corrosion propagates below S-rich products.