The corrosion behavior of 1020C carbon steel samples that had been subjected to oxidizing heat treatment at 550°C and 675°C were studied in sodium chloride electrolytes using a 3-electrode electrochemical impedance spectroscopy. Experimental data were used to evaluate the corrosion behavior of the samples while optical microscopy was employed to investigate the surface characteristics of the samples before and after aqueous corrosion. The results showed that while the sample treated at 550°C revealed an increasing corrosion rate with time, the sample treated at 675°C indicated a higher initial corrosion rate, but the rate declined gradually over the 4-day experimental period. Optical microscopy revealed significant formation of surface corrosion products on both heat treated samples, but the complex plane diagrams indicated significant capacitive behavior for the heat treated samples relative to the untreated samples.
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