Electronic properties and corrosion resistance of passive films on austenitic and duplex stainless steels. (20th May 2018)

• Record Type: Journal Article
• Authors: Tranchida, G.; Clesi, M.; Di Franco, F.; Di Quarto, F.; Santamaria, M.
• Is Part Of: Electrochimica acta. Volume 273(2018)
• Page Start: 412
• Page End: 423
• Publication Date: 2018-05-20
• Subjects: Passive films -- Chromium -- Duplex stainless steel -- Austenitic stainless steel -- Photoelectrochemistry -- Corrosion resistance -- Mott-Schottky; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2018.04.058
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Passive films were grown at constant potential in acidic (pH∼2) and alkaline (pH∼13) solutions on chromium, AISI 304L, AISI 316L and Duplex stainless steels. Passive films on chromium grow following a high field mechanism considering the presence of dissolution phenomena. According to the photoelectrochemical characterization, passive films on Cr have a bandgap of 3.4 eV when formed in acidic solution, and of 2.4 eV when formed in alkaline solution due to the formation of Cr(OH)3 . These films result to be poorly stable against anodic dissolution due to a very anodic flat band potential. Conversely, impedance and photoelectrochemical measurements proved that passive films on stainless steels are chromium rich oxide n-type semiconductors with a very high polarization resistance. Their band gap depends on the pH of the passivation solution and on the SS composition.