Interaction between crevice and galvanic corrosion of X65 carbon steel in the CO2-saturated NaCl solution under the coupling of crevice and galvanic effects

Abstract

• Crevice corrosion could occur in X65 carbon steel (CS) in CO 2 aqueous environment. • Severe corrosion of X65 CS occurs in the X65 CS-316 stainless steel (SS) couple. • The X65 CS-316 SS galvanic effect inside crevice promotes the corrosion of X65 CS. • Crevice effect inhibits the galvanic corrosion of X65 CS in X65 CS-316 SS couple. In this work, with the self-designed setup, the corrosion of X65 carbon steel (CS) in the CO 2 -saturated NaCl solution containing 600 mg/L HAc under the coupling of crevice and galvanic effects was studied by electrochemical tests, weight loss measurement and surface analysis, and the interaction between the crevice and galvanic effects was quantified. It is found that X65 CS undergoes severe corrosion under individual crevice effect or galvanic effect. The accelerated corrosion by galvanic effect is more significant than that by crevice effect. Under the coupling of crevice and galvanic effects, the galvanic effect between X65 CS and 316 stainless steel (SS) promotes the crevice corrosion of X65 CS because of the anodic polarization, while the crevice effect inhibits the galvanic corrosion between X65 CS and 316 SS because their potential difference is significantly reduced in the presence of crevice effect.