Title

EFFECT OF DISSOLVED IONS ON THE NATURE OF CORROSION PRODUCTS FORMED ON CARBON STEEL IN BICARBONATE AND SILICATE CONTAINING CHLORIDE MEDIA: EIS AND XPS STUDY

EFFECT OF DISSOLVED IONS ON THE NATURE OF CORROSION PRODUCTS FORMED ON CARBON STEEL IN BICARBONATE AND SILICATE CONTAINING CHLORIDE MEDIA: EIS AND XPS STUDY

Authorship

DEODESHMUKH, VINAY; ARJUNAN, VENUGOPAL; CHANDRA, DHANESH; DAEMEN, JAAK; YILMAZ, AHMET; LEA, SCOTT; ENGELHARD, MARK; JONES, DENNY

DEODESHMUKH, VINAY

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ARJUNAN, VENUGOPAL

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CHANDRA, DHANESH

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DAEMEN, JAAK

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YILMAZ, AHMET

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LEA, SCOTT

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ENGELHARD, MARK

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JONES, DENNY

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DOI

10.5151/2594-5327-3063

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Abstract

The corrosion behavior of carbon steel in de-aerated 3.5% NaCl solution containing silicate (SiO₃²⁻) and bicarbonate (HCO₃⁻) ions was investigated by Potentiodynamic polarization, Electrochemical Impedance Spectroscopy (EIS), Atomic Force Microscopy (AFM) and X-ray Photo-electron Spectroscopic (XPS) techniques. The results show that, silicate addition with bicarbonate enhances the passivity of carbon steel by decreasing the passive current density and raising the pitting potential. However, the corrosion rate measured at lower potentials indicates the mild effect of silicate due to the complex formation of FeCO₃ with Fe. XPS results indicate the enrichment of silica at passive potential and a mixed FeCO₃ and silica film at lower potentials. This change in film composition was responsible for the changes in corrosion rate at lower and higher potentials.

The corrosion behavior of carbon steel in de-aerated 3.5% NaCl solution containing silicate (SiO₃²⁻) and bicarbonate (HCO₃⁻) ions was investigated by Potentiodynamic polarization, Electrochemical Impedance Spectroscopy (EIS), Atomic Force Microscopy (AFM) and X-ray Photo-electron Spectroscopic (XPS) techniques. The results show that, silicate addition with bicarbonate enhances the passivity of carbon steel by decreasing the passive current density and raising the pitting potential. However, the corrosion rate measured at lower potentials indicates the mild effect of silicate due to the complex formation of FeCO₃ with Fe. XPS results indicate the enrichment of silica at passive potential and a mixed FeCO₃ and silica film at lower potentials. This change in film composition was responsible for the changes in corrosion rate at lower and higher potentials.

Keywords

potentiodynamic polarization, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy

potentiodynamic polarization, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy