Characterization of thermal oxide films formed on a duplex stainless steel by means of confocal-Raman microscopy and electrochemical techniques

Sánchez-Tovar, Rita; Leiva-García, R.; Garcı́a-Antón, J.

doi:10.1016/j.tsf.2014.12.024

Cited by 29 publications

(11 citation statements)

References 68 publications

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“…On the austenite surface, the peaks at 219, 237, 287, 402, and 493 cm −1 were characteristic of α ‐Fe 2 O 3 . The peak at 602 cm −1 was assigned to Cr 2 O 3 , and that at 650 cm −1 was responsible for (Fe,Cr,Mn) 3 O 4 . On the ferrite surface, the peaks at 316 and 369 cm −1 were characteristic of Mn 2 O 3 .…”

Section: Resultsmentioning

confidence: 95%

High‐Temperature Initial Oxidation Behavior in LDX 2101

Zhang

Shi

Liang

et al. 2018

steel research int.

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High-temperature initial oxidation behavior at 1000 C in LDX 2101 oxidized in a closed element is studied. The samples are investigated using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, glow discharge optical emission spectroscopy, and Raman spectra. Results show differences in morphology and development of oxides on the two phases. In the initial stage, the oxide on austenite is granular, whereas that on the ferrite region is homogeneous. However, the entire surface is full of chromium oxide. In the austenite phase, oxide gradually changes from Fe 2 O 3 to Cr 2 O 3 . By contrast, oxide transforms from Mn 2 O 3 to Fe 2 O 3 and then to Cr 2 O 3 in the ferrite phase. In addition, manganese enrichment is observed in the entire oxidation process.

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Section: Resultsmentioning

confidence: 95%

High‐Temperature Initial Oxidation Behavior in LDX 2101

Zhang

Shi

Liang

et al. 2018

steel research int.

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“…A identificação dessas de acordo com a literatura é característica de materiais passivos que apresentam as camadas interna compacta e a externa porosa, 43, 45 e que em aços inoxidáveis são formadas respectivamente de óxidos de cromo e ferro e de hidróxidos ferro e cromo. 46 Os resultados apresentados nas Figuras 6, 7, 8 e 9 mostram que os aços têm comportamentos equivalentes, isto é, boa resistência à corrosão por pite em todas as condições de ensaio (OCP), demonstrando que os aumentos das concentrações de cloretos e as saturações das soluções não foram suficientes para causar danos significativos nos filmes passivos, de acordo com a literatura os expressivos valores de impedância encontrados nos aços super duplex, estão relacionados às altas quantidades de óxido de cromo nos filmes. 47 As pequenas variações que demostraram melhor desempenho do filme passivo do aço S32760 em alguns intervalos de médias a baixas frequências não foram suficientes para determinar superioridade das camadas dos filmes em termos de resistência à corrosão por pite.…”

Section: Os Diagramas Deunclassified

Electrochemical Evaluation of Pitting Corrosion Resistance on Duplex and Super Duplex Stainless Steels in Seawater Solutions

et al. 2017

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Abstract:The corrosion resistance of solubilized duplex and super duplex stainless steels was investigated at different concentrations of Cl -(3.5 to 7%) and different pH ranges (4.0 to 6.9). Electrochemical techniques were used to characterize the resistance of the passive film that was evaluated from the open circuit potential (OCP), in sea water simulator environments, through experiments of Anodic Potenciodynamic Polarization, Electrochemical Impedance Spectroscopy (EIS) up to the Pite potential and Electrochemical Scanning Microscopy (SECM). Microstructural characterization was performed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) and Vickers microhardness. The microstructure identified in the steels was austenitic and ferritic, without the presence of secondary phases. The behavior of the passive films of the stainless steels presented similar characteristics in the EIS experiments, however in the anodic polarizations the duplex steel behaved slightly superior. Scanning electrochemical microscopy revealed regions with electrochemical activities, which indicate the formation of pitting precursors.Keywords: Duplex and super duplex stainless steel; Electrochemical techniques; Pitting corrosion. ResumoA resistência à corrosão dos aços inoxidáveis duplex e super duplex solubilizados foi investigada em diferentes concentrações Cl -(3,5 a 7 %) e diferentes faixas de pH (4,0 a 6,9). Foram utilizadas técnicas eletroquímicas para caracterização da resistência do filme passivo que foi avaliado a partir do potencial de circuito aberto (OCP), em ambientes simuladores de água do mar, através de experimentos de Polarização Potenciodinâmica Anódica, Espectroscopia de Impedância Eletroquímica (EIS) até o potencial de pite e Microscopia de varredura eletroquímica (SECM). A caracterização microestrutural foi realizada por Microscopia Óptica (MO), Microscopia Eletrônica de Varredura (MEV-EDS), Difração de raios X (DRX) e microdureza Vickers. A microestrutura identificada nos aços foi austenita e ferrita, com ausência de fases secundárias. O comportamento dos filmes passivos dos aços inoxidáveis apresentaram características semelhantes nos experimentos de EIS, porém nas polarizações anódica o aço duplex comportou-se ligeiramente superior. A microscopia eletroquímica de varredura revelou regiões com atividades eletroquímicas, que indicam a formação de precursores de pites.Palavras-chave: Aços inoxidáveis duplex e super duplex; Técnicas eletroquímicas; Corrosão por pite.

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“…[ 1–4 ] However, colored oxide films on the surface of ferritic stainless steel will be formed and further impair the corrosion resistance during applications such as heating and welding. [ 5–9 ] The ferritic stainless steel usually shows colors such as yellow, red, blue, and gray when exposed to high temperatures over a range from 300°C to 850°C. [ 6,7 ] The colors mainly indicate different film thicknesses, while it can be also considered as an indicator of corrosion attack and be applied for an underlying diagnostics on corrosion properties.…”

Section: Introductionmentioning

confidence: 99%

“…Corrosion behavior of stainless steel is commonly assessed by dynamic polarization and electrochemical impedance spectroscopy (EIS) measurement. [ 5,24,25 ] Different equivalent circuits are proposed to simulate the electrochemical behavior of oxide films formed on stainless steel. [ 18,24,26–28 ] Information on electrochemical properties and the structure of oxide films, as well as the presence of pores in the films, can be obtained by an interpretation of impedance spectra of the films.…”

Section: Introductionmentioning

confidence: 99%

Optical spectroscopic and electrochemical characterization of oxide films on a ferritic stainless steel

Fan

Shi

Sharafeev

et al. 2020

Materials & Corrosion

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Colored oxide films that form on ferritic stainless steel in a high‐temperature, oxidizing environment and correspond to different chemical compositions can cause a deterioration of pitting resistance and corrosion performance. Herein, optical spectroscopic and electrochemical techniques have been used to reveal the relationship between color, chemical composition, and corrosion resistance of oxide films formed in the temperature range from 400°C to 800°C for 30 min and at 800°C for 10, 20, 30, and 60 min. The substrate with a thin and dense passivation film leads to a low pitting potential but high corrosion resistance. Oxide films of yellowish or brownish color formed below 600°C are mainly iron oxides, which correspond to low corrosion resistance. No passivation characteristics can be observed for polarization curves of oxide films formed at 500°C and 600°C. The color of oxide films varies from blue to dark gray with the increase of oxidation time at 800°C. Corrosion resistance changes with different proportions of Fe3O4, Cr2O3, and FeCr2O4. The gray oxide films formed at 800°C for 30 min exhibit the lowest pitting susceptibility and the highest corrosion resistance.

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Characterization of thermal oxide films formed on a duplex stainless steel by means of confocal-Raman microscopy and electrochemical techniques

Cited by 29 publications

References 68 publications

High‐Temperature Initial Oxidation Behavior in LDX 2101

High‐Temperature Initial Oxidation Behavior in LDX 2101

Electrochemical Evaluation of Pitting Corrosion Resistance on Duplex and Super Duplex Stainless Steels in Seawater Solutions

Optical spectroscopic and electrochemical characterization of oxide films on a ferritic stainless steel

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