Study of the electrochemcial behaviour of a carbon steel electrode in sodium sulfate aqueous solutions using electrochemical impedance spectroscopy

摘要

The study of a plain carbon steel (AISI 1020) in Na_2SO_4 aqueous solutions at different concentrations was carried out by electrochemical impedance spectroscopy (EIS) in order to determine the corrosion mechanism and to obtain representative corrosion rates of the system. EIS was used to measure corrosion current densities at high concentrations in the range 0.1-1 wt% Na_2SO_4, but in the low concentration range, from 0.001 to 0.01 wt%, a scattered Nyquist plot was obtained. Other electro-chemical techniques, such as polarization resistance (PR), Tafel plots and electrochemical noise (EN), were also used in this analysis. The charge transfer resistance was determined and compared with the PR and noise resistance.