Elucidation of electrochemical and morphological difference of carbon steel corroded in aqueous chloride solutions at low temperatures

In humid continental climate areas, brine rejection results in the metal being exposed to higher and changing concentrations of chloride ions derived from precipitation. In this study, the corrosion behavior of carbon steel in different conditions especially in high chloride ions concentrations and at low temperature were investigated via electrochemical methods Liner Sweep voltammetry (LSV), Electrochemical Impedance Spectroscopy (EIS), and surface analysis. The results indicate that the dominant factor in affecting current in the temperature range from 20 degrees C to 0 degrees C is different from that in the range from 0 degrees C to-20 degrees C. It was found that the charge transfer reactions were inhibited in high concentrated NaCl solutions, and corrosion morphology changed from pitting corrosion to general corrosion due to the frequent occurrence of passive film destruction induced by chloride ions. Furthermore, in addition to the common corrosion products found at both 0 degrees C and 20 degrees C, Fe3O4 / gamma-Fe2O3 was detected only at 20 degrees C.

Automated summary

The corrosion behavior of carbon steel in high chloride ions concentrations and at low temperature was examined using electrochemical methods and surface analysis. It was found that the dominant factor affecting current differs in the temperature range from 20°C to 0°C compared to the range from 0°C to -20°C. High concentrations of NaCl inhibited charge transfer reactions, leading to the transformation of corrosion morphology from pitting corrosion to general corrosion due to frequent destruction of the passive film induced by chloride ions. Additionally, Fe3O4 / gamma-Fe2O3 was only detected at 20°C, in addition to the common corrosion products found at both 0°C and 20°C.