Monitoring initial pitting behaviors of 30CrMnSi steel in NaHCO-NaCl solution by ESPI and electrochemical noise

Abstract

The initial pitting behaviors of 30CrMnSi steel in 0.05 mol/L NaCl + 0.5 mol/L NaHCO₃ solution was studied using electric speckle pattern interferometery (ESPI) and electrochemical noise (EN). Results show that the bright speckles and sharp fluctuation of electrochemical signals occurred at the same time. The EN curve shows that there are three stages during the pitting process - the induction stage (0–50 s), the incubation stage (50–300 s) and the initiative stage (300–512 s).

Keywords

30CrMnSi steel / pitting / ESPI / EN