Electrochemical Behavior of 304 Stainless Steel in Marine Atmosphere and Its Simulated Solution

Abstract

The electrochemical behavior of field-exposed 304 stainless steel in a marine atmospheric environment and its simulated solutions were studied by corrosion rates test, cyclic anodic polarization (CAP), electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP). The morphology, composition, and structure of the rust were analyzed by different methods: SEM, EDS, and Raman spectroscopy. The electrochemical experiments showed that the exposure samples in the marine atmosphere-simulated solution have a characteristic of lower pitting potential, and the stability of passive film became weak with exposure time extension. The corrosion products of 304 stainless steel in Xisha marine atmosphere are mainly the β-FeOOH, γ-Fe₂O_3, and Fe₃O₄. The Kelvin potential of the samples’ surface declined after 12 months exposure and tends to be uneven.

Keywords:

• Atmospheric corrosion
• SEM
• SKP
• Stainless steel

Acknowledgments

This work is supported by the Fundamental Research Funds for the Central Universities (No. FRF-TP-11-006B) and the National Natural Science Foundation of China (No.51131005, No. 51171023).