Effect of thiosulphate/H₂S on crevice corrosion behaviour of P110 carbon steel in CO₂-saturated solution

ABSTRACT

The effect of thiosulphate/H₂S on crevice corrosion behaviour of P110 carbon steel in the CO₂-saturated 3.5 wt% NaCl solution was investigated. The results showed that crevice corrosion of P110 steel could not occur in the CO₂-saturated solution, likely due to the inhibition of both anodic and cathodic reactions inside crevice. Further, the structure of corrosion product film along the crevice wall is influenced by the concentration of thiosulphate. Increasing the concentration of thiosulphate to 10⁻² mol L⁻¹ promotes the formation of fine flake-like mackinawite outside crevice. In addition, crevice corrosion of P110 steel in the CO₂-saturated solution is promoted by increasing the concentration of thiosulphate. This is because the dense and fine mackinawite film on the steel surface has a better protectiveness and could enhance cathodic reaction rate outside crevice.

KEYWORDS:

• Crevice corrosion
• carbon steel
• corrosion product film
• CO₂
• H₂S
• thiosulphate

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Lijin Dong http://orcid.org/0000-0002-8484-7537

Additional information

Funding

This work is supported by the Open Research Fund from State Key laboratory of Metal Material for Marine Equipment and Application (SKLMEA-K201912), Youth Scientific and Innovation Research Team for Advanced Surface Functional Materials (Southwest Petroleum University, No. 2018CXTD06), Scientific Research Starting Project of SWPU (No. 2019QHZ012) and the Young Scholars Development Fund of Southwest Petroleum University (No. 201899010040).