Evaluation of Corrosion Resistance of Two Kinds of Hull Steels by Electrochemical Noise

The corrosion behavior of two hull steels immerged in 0.5 mol/L NaHCO3+3% NaCl aqueous solution was investigated by electrochemical noise (EN) technology and polarization curve method. Distinct pitting characteristics could be observed from EN spectra of the two steels. The results indicated that the duration of pits initiation for steel B was shorter, and its potential noise fluctuations were also bigger and denser than those of steel A. The results of noise resistance showed that the surface condition of steel A was more stable than that of steel B. The results of polarization curves showed that steel A had higher pitting potential, bigger polarization resistance and smaller corrosion current than those of steel B, well in accordance with the results of electrochemical noise analysis.