Electrochemical Comparative Study of Q235 steel and 304 SS in Simulated Concrete Pore Solutions and the Effect of Chloride Ions on their corrosion behavior

Abstract

The corrosion behavior of Q235 carbon steel and 304 stainless steel (SS) was studied by potentiodynamic polarization in four types of simulated concrete pore solutions (pH 13.3, 11.5, 9.7). The results showed that both steels maintained good passivation in the pore solutions, demonstrating similar corrosion resistance. The addition of 0.05 mol/L of Cl had no influence on the corrosion resistance of 304 SS in the solutions, whereas pitting corrosion susceptibility of Q235 carbon steel increases in the carbonate solutions. 304 SS performed much better than Q235 carbon steel in carbonated pore solutions with the critical chloride concentration 100 times higher than that of Q235 carbon steel. The presence of NaHCO3 and Na2CO3 increased the critical [Cl ] for pitting corrosion because of the inhibitive effect of HCO3/CO3 2on the pitting corrosion.