Effect of Temperature on Electrochemical Corrosion Behavior of N80 Steel in CO₂ Saturated NaCl Solution

The effect of temperature on corrosion behavior of N80 steel in CO2 saturated NaCl solution was investigated by dynamic polarization and electrochemical impedance spectroscopy (EIS). The results show that the EIS has three time constants for the capacitance at high frequency, the inductance at middle and low frequency and the capacitance at low frequency. The capacitance at high frequency is related to the capacitance of the double layer and transfer resistance, the inductance is attributed to the coverage of the corrosion product film and the adsorption of the intermediate corrosion product, and the capacitance appearing at low frequency is related to the formation of the corrosion product film. With increasing the temperature, the inductance arc shrinks, and the capacitance arc at low frequency enlarges, indicating that increasing temperature may accelerate the formation of the corrosion film. At 70 ℃, the EIS had only two time constants and the inductance arc disappeared.