Influence of Cl^- on Corrosion Behavior of 2Cr13 Steel in H₂S/CO₂ Saturated Solutions

The influence of Cl- on corrosion behavior of 2Cr13 steel in H2S/CO2 saturated solutions was investigated by weight loss method and electrochemical measurement technology. Morphology, elements and composition of corrosion products on the surface of 2Cr13 steel specimens were analyzed by means of SEM, EDS and XRD. The results showed that the increase of Cl- content aggravated the corrosion rate of 2Cr13 steel in H2S/CO2 saturated solutions, which would reach the maximum value at concentration of Cl- 20 g/L. Corrosion products of 2Cr13 steel specimens consisted mainly of quartet pyrite FeS and a small amount of Fe1-xS. The electrochemical process of 2Cr13 steel active dissolution corrosion was controlled by cathode diffusion process. The existence of Cl- in H2S/CO2 saturated solutions did not change the active dissolution situation of 2Cr13 steel corrosion and the electrochemical reaction mechanism, only could have an impact on the corrosion tendency and the value of corrosion rate.