Non-uniform distribution of passive film formed on carbon steel

Koji Fushimi, Ryogo Nakagawa, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa

Research output: Contribution to conferencePaperpeer-review

Abstract

Passive film of S45C carbon steel formed in pH 8.4 boric acid-borate buffer solution was investigated by using scanning electrochemical microscopy (SECM). Passivity-maintaining current of the carbon steel was about 3 times as large as that of pure iron. Current of electron-transfer reaction (ETR) of redox mediator through the passive film was strongly dependent on metallographic structure of the carbon steel. For example, the passive film formed on perlite eutectic phase in the carbon steel allowed larger ETR current than that formed on primary phase ferrite. Raman spectroscopy revealed that the surface of carbon steel was covered with non-uniform magnetite and amorphous carbon. It was suggested that cementite in the perlite affected not only the formation of oxide but also the semi-conductive property of the film.

Original languageEnglish
Publication statusPublished - 2017
EventJoint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017 - Prague, Czech Republic
Duration: 3 Sept 20177 Sept 2017

Conference

ConferenceJoint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017
Country/TerritoryCzech Republic
CityPrague
Period3/09/177/09/17

Keywords

  • Cementite
  • Heterogeneity of passive film
  • Imaging Raman spectroscopy
  • Perlite
  • Scanning electrochemical microscopy

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