Corrosion Behavior of J55 Steel in NaHCO₃ Solution

The corrosion behavior of J55 steel in the NaHCO3 solutions with different concentrations was studied using electrochemical impedance spectroscopy (EIS) technique.The results show that the EIS presented single capacitance arc and contractive characteristic at the end when the concentration of HCO-3 was 1 g·L-1 and 5 g·L-1.When the concentration of HCO-3 increased to 10 g·L-1 the EIS presented capacitance arc in high frequency region,while inductance arc in low frequency region.When the concentration of HCO-3 increased to 30 g·L-1 the EIS presented Warburg impedance characteristic.The dispersive exponent increased with the increase of the concentration of HCO-3 from 1 g·L-1 to 5 g·L-1,while decreased from 5 g·L-1 to 30 g·L-1.With the HCO-3 concentration increased from 1 g·L-1 to 5 g·L-1 the corrosion rate increased,and decreased from 5 g·L-1 to 30 g·L-1.