Inhibition of Carbon Steel Corrosion in Neutral Calcareous Synthetic Water by Eruca sativa Extract

Resumo

Here, by various electrochemical and analytical techniques, we have examined whether Eruca sativa aqueous extract can inhibit the corrosion of carbon steel in calcareous synthetic water. We detected differences in the morphology and phases of the films formed on the metallic surface under corrosion conditions. The electrochemical results suggest that, in the presence of E. sativa extract, the observed decrease in the corrosion current is associated with an increase in polarization resistance. EIS results reveal the presence of two time constants. The first one, at high frequency range (HF), is associated to the faradic process. The second one, at low frequency (LF), is related to the redox reaction occurring in the passive film. The highest inhibition efficiency, related to the large fraction of phenolic compounds present in the extract, can reach up to 95% with a dose of only 30 ppm.