Abstract
The objective of this study is to clarify the preferential dissolution mechanism of a duplex stainless steel (DSS) at its corrosion potential (about -0.15 V vs.SHE) by means of Scanning Electrochemical Microscope (SECM) observation of the corrosion reactions on the ferritic phase (α phase) and the austenitic phase (γ phase) of a DSS, respectively. Probe electrode was fixed above α and γ each phase of DSS at corrosion potential in 1 mol/l HCl aqueous solution. Potential of the probe electrode was polarized toward noble direction, from - 0.10 V to 1.4 V (SHE), at a potential scan rate of 20 mV/s, and probe current was measured. In a probe potential range of 0∼0.70 V (SHE), anodic current due to hydrogen oxidation reaction could be detected. This anodic current was larger above y phase than that above α phase. In a probe potential range of 0.70∼1.2 V (SHE), anodic current due to Fe2+ oxidation reaction to Fe3+ could be detected. This anodic current was larger above a phase than that above y phase. On the α phase, the anodic dissolution reaction occurred preferentially at the DSS corrosion potential, while on the γ phase, the cathodic reduction reaction of hydrogen ion occurred preferentially.
Original language | English |
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Pages (from-to) | 414-420 |
Number of pages | 7 |
Journal | Zairyo to Kankyo/ Corrosion Engineering |
Volume | 64 |
Issue number | 9 |
Publication status | Published - 2015 |
Keywords
- Austenitic phase
- Duplex stainless steel
- Ferritic phase
- Hydrogen evolution
- Preferential dissolution
- Scanning electrochemical microscope
ASJC Scopus subject areas
- Electrochemistry
- Materials Chemistry
- Metals and Alloys
- Surfaces, Coatings and Films