Activation and Repassivation of Stainless Steels in Artificial Brines as a Function of pH
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Slovenian National Building and Civil Engineering Institute, Dimičeva ulica 12, 1000 Ljubljana, Slovenia
2
OMV Austria Exploration & Production GmbH, Protteser Strasse 40, 2230 Gaenserndorf, Austria
3
Department of General, Analytical and Physical Chemistry, Montanuniversitaet Leoben, Franz Josef-Strasse 18, 8700 Leoben, Austria
*
Author to whom correspondence should be addressed.
Materials 2019, 12(23), 3811; https://doi.org/10.3390/ma12233811
Received: 22 October 2019
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Revised: 14 November 2019
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Accepted: 16 November 2019
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Published: 20 November 2019
(This article belongs to the Special Issue Development of Mechanical, Corrosion Resistance, and Antibacterial Properties of Steels)
When planning oil wells with stainless steel components, two possible reasons for depassivation have to be considered—chemical depassivation caused by acidizing jobs and mechanical depassivation caused by various tools and hard particles. The study explores conditions causing chemical activation of investigated steels and circumstances under which repassivation occurs after activation. The main focus of the study is to determine, how quickly various steels can repassivate under different conditions and to find pH values where repassivation will occur after depassivation. The investigated steels were ferritic (martensitic or bainitic) in the cases of 13Cr, 13Cr6Ni2Mo, and 17Cr4Ni2Mo, austenitic in the case of 17Cr12Ni2Mo, and duplex (austenitic and ferritic) in the case of 22Cr5Ni3Mo. Potentiodynamic experiments were employed to obtain electrochemical properties of investigated steels, followed by immersion tests to find ultimate conditions, where the steels still retain their passivity. After obtaining this information, scratch tests were performed to study the repassivation kinetics. It was found that repassivation times are similar for nearly all investigated steels independent of their chemical composition and microstructure.
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Keywords:
stainless steels; activation; repassivation
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MDPI and ACS Style
Mujanović, E.; Zajec, B.; Kosec, T.; Legat, A.; Hönig, S.; Zehethofer, G.; Mori, G. Activation and Repassivation of Stainless Steels in Artificial Brines as a Function of pH. Materials 2019, 12, 3811. https://doi.org/10.3390/ma12233811
AMA Style
Mujanović E, Zajec B, Kosec T, Legat A, Hönig S, Zehethofer G, Mori G. Activation and Repassivation of Stainless Steels in Artificial Brines as a Function of pH. Materials. 2019; 12(23):3811. https://doi.org/10.3390/ma12233811
Chicago/Turabian StyleMujanović, Emir, Bojan Zajec, Tadeja Kosec, Andraž Legat, Stefan Hönig, Gerald Zehethofer, and Gregor Mori. 2019. "Activation and Repassivation of Stainless Steels in Artificial Brines as a Function of pH" Materials 12, no. 23: 3811. https://doi.org/10.3390/ma12233811
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