Correlation between critical pitting temperature and degree of sensitisation on alloy 2205 duplex stainless steel

Ebrahimi, Nafiseh; Momeni, Mojtaba; Moayed, Mohammad Hadi; Davoodi, Ali

doi:10.1016/j.corsci.2010.10.009

Cited by 97 publications

(37 citation statements)

References 39 publications

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“…Primarily the ferrite was corroded under the droplet deposit with some minor corrosion observed on the austenite. The same corrosion pattern has previously been reported under similar exposure conditions [45,63,64], with ferrite clearly the electrochemically more active phase leading to selective dissolution [17,18,44,45,56,[64][65][66][67][68][69][70][71][72]. The ferrite phase is, usually, the electrochemically more active phase in 2205 duplex stainless steel Fig.…”

Section: As-received Microstructuresupporting

confidence: 58%

Correlative EBSD and SKPFM characterisation of microstructure development to assist determination of corrosion propensity in grade 2205 duplex stainless steel

Örnek

Engelberg

2015

J Mater Sci

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Correlative electron backscatter diffraction (EBSD) and scanning Kelvin probe force microscopy (SKPFM) analysis has been carried out to characterise microstructure development and associated corrosion behaviour of as-received and 750°C heat-treated grade 2205 duplex stainless steel. High-resolution EBSD analysis revealed the presence of r-and v-phase, secondary austenite, Cr 2 N, and CrN after ageing treatment. SKPFM Volta potential measurements confirmed the formation of discrete reactive sites, indicating local corrosion propensity in the microstructure. Cr 2 N, r-phase, and inter-granular v-phase had the largest net cathodic activity, followed by CrN and intra-granular v-phase showing medium electrochemical activity, with ferrite and austenite (including secondary austenite) showing net anodic activity. Corrosion screening confirmed selective corrosion of ferrite in the as-received and 750°C-aged conditions with the corrosion propensity of secondary phases staying in-line with SKPFM observations. Stress corrosion micro-cracks were also observed and are discussed in light of microstructure corrosion propensity.

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Section: As-received Microstructuresupporting

confidence: 58%

Correlative EBSD and SKPFM characterisation of microstructure development to assist determination of corrosion propensity in grade 2205 duplex stainless steel

Örnek

Engelberg

2015

J Mater Sci

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“…As far as corrosion resistance is concerned, σ phase formation promotes an increase in the DOS 7,[16][17][18][20][21][22][23] probably as a result of etching to adjacent areas of formed σ phase, as these regions are likely to be depleted in chromium and/ or molybdenum. Some authors, working with UNS S31803 DSS aged at 650°C, show that, after DL-EPR tests in a 2 M H 2 SO 4 + 0.5 M NaCl + 0.01 M KSCN solution, the DOS increases from 0.036236 (samples aged for 16 h) to 0.824235 (samples aged for 527 h) 7 , while others show that, after DL-EPR tests in a 0.3 M HCl + 0.002 M Na 2 S 2 O 3 solution, the DOS increases from 0.075 (samples aged for 60 min) to 0.2574 (samples aged for 300 min) 22 . Recent studies related to isothermal heat treatments of DSS at 650°C are mainly based upon σ phase formation 6,7 ; however, the possibility of χ phase formation and even of Cr 2 N formation may not be neglected, as there is lack of information about such phases as far as heat treatments below 700°C are concerned.…”

Section: Results Presented By Borba and Magnaboscomentioning

confidence: 99%

Influence of the microstructure on the degree of sensitization of a duplex stainless steel UNS S31803 aged at 650ºC

Melo¹,

Magnabosco²,

Neto³

2013

Mat. Res.

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This work evaluates the phase transformations during aging of an UNS S31803 DSS at 650°C and its influence on the DOS. The material was solution treated at 1175°C and then aged at 650°C for times up to 360 h. SEM-BSC images indicate the formation of Cr 2 N, σ and χ phases in the samples aged at 650°C. The analysis of DL-EPR curves, obtained in a 1 M H 2 SO 4 + 0.25 M NaCl + 0.01 M KSCN solution, shows an increase in DOS values for samples aged at 650°C. Probably, this increase observed in DOS values is mainly related to the presence of Cr-and/or Mo-depleted α, as a result of σ phase, χ phase and/or Cr 2 N formation at 650°C. Moreover, a possible healing up of Cr-and/ or Mo-depleted areas is observed between 1 h and 4 h of aging at 650°C.

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“…Thus, Cl − ions are aggressive enough to attack stainless steel and leads to a localized corrosion (e.g. pitting corrosion) due to small ion radius, which enable it to penetrate the oxide film under high electrical field present through the film as mentioned by researcher [16] [17] [19]. The electrical neutrality and hydrolysis of the corrosion product inside the pit was enhanced by Cl − ion migration cause pH dropped from 6 to 2 (acidification) facilitate the corrosion process as represented by the chemical Equation (1) …”

Section: Halide Effect On Pitting Corrosionmentioning

confidence: 99%

Comparison of Aggressiveness Behavior of Chloride and Iodide Solutions on 304 and 304L Stainless Steel Alloys

Salih¹,

Shakir²,

Al-Sammarraie³

2017

MSA

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The aggressive effect of chloride anion in comparison to iodide anion on the pitting corrosion attack of 304 and 304L stainless steel (SS) alloys was investigated by using the cyclic potentiodynamic polarization test at 0.6 M Sodium Halide salts (NaX) solution and different temperatures. The two alloys 304 and 304L SS suffered from severe pitting corrosion at room temperature up to 50˚C in a chloride containing solution with the higher resistance observed for 304L in comparison to the 304 while on pits were detected in iodide solution for both alloys. The pitting potentials of the two alloys in 0.6 M NaCl solution reduced with the increase of the temperature. Examination of the alloys' surfaces was conducted by using the scanning electron microscopes where it revealed that the occurrence of pitting attack seems like hemispherical or irregular pits with different sizes.

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Correlation between critical pitting temperature and degree of sensitisation on alloy 2205 duplex stainless steel

Cited by 97 publications

References 39 publications

Correlative EBSD and SKPFM characterisation of microstructure development to assist determination of corrosion propensity in grade 2205 duplex stainless steel

Correlative EBSD and SKPFM characterisation of microstructure development to assist determination of corrosion propensity in grade 2205 duplex stainless steel

Influence of the microstructure on the degree of sensitization of a duplex stainless steel UNS S31803 aged at 650ºC

Comparison of Aggressiveness Behavior of Chloride and Iodide Solutions on 304 and 304L Stainless Steel Alloys

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