Passive properties of lean duplex stainless steels after long-term ageing in air studied using EBSD, AES, XPS and local electrochemical impedance spectroscopy

• Published in: Corrosion science Vol. 67; pp. 109 - 117
• Main Authors: Vignal, V., Krawiec, H., Heintz, O., Mainy, D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-02-2013; Elsevier
• Subjects: A. Stainless steel; Applied sciences; B. AES; B. EIS; B. XPS; C. Passivity; Corrosion; Corrosion environments; Exact sciences and technology; Metals. Metallurgy; B. XPS; C. Passivity; B. AES; B. EIS; A. Stainless steel; Electron diffraction; Austenitic ferritic steel; Ageing; Air; Passivity; Corrosion; Stainless steel; Photoelectron spectrometry; Duplex stainless steel; Impedance; Dual phase steel; Passivation
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2012.10.009

► Influence of long-term ageing on passivity of duplex stainless steels. ► Influence of the crystallographic orientation of grains on passivity of duplex stainless steels. ► Surface analysis and electrochemical investigations at the microscale within both phases.
Passivity of duplex stainless steel was studied after long-term ageing in air using local electrochemical impedance spectroscopy, AES, XPS and EBSD. After mechanical polishing, the passive film was homogeneous and had a capacitive behaviour described by the CPE. After long-term ageing, a small thickening was detected and O2−/OH− was significantly higher in the austenite than in the ferrite. Austenite behaved as a blocking electrode whereas two capacitive loops were observed in the ferrite (low value of O2−/OH). The loop at high frequencies was related with the oxygen reduction and the loop at low frequencies was connected with the passive film.