TY - JOUR
T1 - Relationships between pitting corrosion potentials and MnS dissolution of 5–18 mass% Cr steels
AU - Asano, Shinpei
AU - Muto, Izumi
AU - Sugawara, Yu
AU - Hara, Nobuyoshi
N1 - Funding Information:
This work was supported by JSPS KAKENHI grant Numbers JP15K14175 and JP 17H01331 from the Japan Society for the Promotion of Science. This research was also supported by Japan Society and Technology Agency (JST) under Collaborative Research Based on Industrial Demand “Heterogeneous Structure Control: Towards Innovation Development of Metallic Structural Materials.”
Publisher Copyright:
© The Author(s) 2018. Published by ECS.
PY - 2018
Y1 - 2018
N2 - With the increase in the Cr content in the steels, the Cr and Fe concentrations in the inclusions increased and decreased, respectively. The MnS inclusions were found to dissolve in 0.1 M Na2SO4 around 0 V vs. Ag/AgCl, (3.33 M KCl). Even though the dissolution potential was independent of Cr concentration, the dissolution morphology was remarkable in that the inclusions in Fe-5Cr dissolved and disappeared. For Fe-12Cr, the Cr-enriched portions remained. In the case of Fe-18Cr, Cr-oxides formed on the inclusion surfaces. The micro-scale polarization was performed in 0.1 M NaCl. At approximately 0.05 V, a large pit was generated at the inclusion of Fe-5Cr, and the inclusion disappeared after polarization. For Fe-12Cr, a stable pit was initiated at 0.13 V, and most of the inclusion remained. No stable pit occurred on Fe-18Cr; however, a meta-stable pitting event was observed in the dissolution potential region of the MnS. Cr and O were detected on the entire surface on the inclusion after polarization. It was suggested that the pitting corrosion resistance at the MnS inclusions of Fe-Cr alloys was related to the inclusion dissolution morphology originating from the difference in the Cr concentration of the inclusions.
AB - With the increase in the Cr content in the steels, the Cr and Fe concentrations in the inclusions increased and decreased, respectively. The MnS inclusions were found to dissolve in 0.1 M Na2SO4 around 0 V vs. Ag/AgCl, (3.33 M KCl). Even though the dissolution potential was independent of Cr concentration, the dissolution morphology was remarkable in that the inclusions in Fe-5Cr dissolved and disappeared. For Fe-12Cr, the Cr-enriched portions remained. In the case of Fe-18Cr, Cr-oxides formed on the inclusion surfaces. The micro-scale polarization was performed in 0.1 M NaCl. At approximately 0.05 V, a large pit was generated at the inclusion of Fe-5Cr, and the inclusion disappeared after polarization. For Fe-12Cr, a stable pit was initiated at 0.13 V, and most of the inclusion remained. No stable pit occurred on Fe-18Cr; however, a meta-stable pitting event was observed in the dissolution potential region of the MnS. Cr and O were detected on the entire surface on the inclusion after polarization. It was suggested that the pitting corrosion resistance at the MnS inclusions of Fe-Cr alloys was related to the inclusion dissolution morphology originating from the difference in the Cr concentration of the inclusions.
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U2 - 10.1149/2.0271811jes
DO - 10.1149/2.0271811jes
M3 - Article
AN - SCOPUS:85067395486
VL - 165
SP - C732-C742
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 11
ER -