Crevice Corrosion on Ni-Cr-Mo Alloys

Jakupi, Pellumb; Zagidulin, Dmitrij; Noel, John; Shoesmith, D.W.

doi:10.2172/893712

Cited by 19 publications

(65 citation statements)

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“…The time between electrode preparation and its immersion in solution was minimized to avoid complications due to air oxidation . A period of ~60 min of cathodic cleaning at –1.0 V was required to guarantee a reproducible surface.…”

Section: Methodsmentioning

confidence: 99%

Characterization of surface composition on Alloy 22 in neutral chloride solutions

Zagidulin

Zhang

Zhou

et al. 2012

Surface & Interface Analysis

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The composition of anodically grown oxide films on Alloy 22, a Ni‐Cr‐Mo(W) alloy, has been investigated in 5 mol l−1 NaCl at room temperature using X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry. For applied potentials up to 0.2 V (vs Ag/AgCl (saturated KCl solution)), a Cr(III) oxide barrier layer develops at the alloy/oxide interface accounting for the excellent passivity demonstrated to prevail in this potential region by previous electrochemical impedance spectroscopy measurements. At higher potentials, this layer is destroyed by defect injection as Cr(III) is oxidized to the more soluble Cr(VI). The overall oxide/hydroxide film thickness is, however, increased as Mo(VI)/W(VI) species accumulate at the oxide solution interface. The potential of 0.2 V at which the barrier layer switches from growth to destruction coincides with the previously demonstrated threshold potential for the initiation of crevice corrosion. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Characterization of surface composition on Alloy 22 in neutral chloride solutions

Zagidulin

Zhang

Zhou

et al. 2012

Surface & Interface Analysis

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“…exhibits coincidence for 1/5 of the lattice points [39]. P values 29, designated 'special' boundaries, are well known to possess extraordinary properties compared to high angle 'random' boundaries [40], including a greater resistance to corrosion [41,42]. The number and type of CSL boundaries provides some indication of the effectiveness of the recrystallization process.…”

Section: Annealed Cu Cold Spray Coatingsmentioning

confidence: 99%

Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

Jakupi

Keech

Barker

et al. 2015

Journal of Nuclear Materials

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“…Raman spectroscopy analysis of the corrosion products from Alloy 22 exposed to hot chloride brine detected MoO 2 and Mo 4 O 11 . 27 To study the stability of the corrosion products from the crevice area in a low pH environment, soak tests were performed in 0.1, 1, and 6 M HCl solutions. About 0.025 g of the corrosion products was soaked in 2 cm 3 of each solution at 95°C.…”

Section: Distribution Morphology and Surface Analyses Of Crevice Comentioning

confidence: 99%

“…1 Localized corrosion is an important degradation mode to be evaluated for the corrosion performance of Alloy 22 over long exposure periods, and it has been examined by a number of researchers. [3][4][5][6][7][8][9][10][11][12][13] Many factors affecting the localized corrosion behavior of Alloy 22 have been studied, such as the effects of Cl − and oxyanions, 3,4,[14][15][16] the effects of potential and temperature, 5,17 and the propagation and stifling of the crevice corrosion. 5,9,18,19 During the crevice corrosion process, corrosion products are formed.…”

mentioning

confidence: 99%

Characterization of the Corrosion Products of Crevice Corroded Alloy 22

Payer

2009

J. Electrochem. Soc.

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The crevice corrosion performance of Alloy 22 was tested under potentiostatic polarization more positive than the repassivation potential in 4 M NaCl solution at 100°C. Under this aggressive condition, crevice corrosion initiated under the crevice contacts and four stages of corrosion behavior were observed: initiation, propagation, stifling ͑corrosion slowed͒, and arrest ͑corrosion stopped͒. During the exposure, dark green deposits were found on the uncorroded metal surface around the crevice contacts, light green precipitations were found in the test solution, and the solution color changed from clear to light green. After exposure, loose black corrosion products were found under the crevice contacts. Surface analyses at the sites of varying corrosion penetrations showed similar composition depth profiles, and the results indicated that a 3-5 nm thick, chromium-rich oxide film was formed on the alloy surface. The composition depth profiles indicated that the crevice corrosion occurred by a uniform, nonselective dissolution. Surface analysis results showed that the corrosion products in the crevice were rich in O, enriched with Mo and W, and depleted of Ni and Cr relative to the bulk alloy. A solution analysis showed that Ni was the main element dissolved into the solution during the exposure. Alloy 22 ͑UNS N06022͒, a nickel-chromium-molybdenum ͑Ni-Cr-Mo͒ alloy, has a high uniform corrosion resistance in oxidizing environments and a superior corrosion resistance in reducing corrosion media. It also exhibits an excellent resistance to localized corrosion, such as pitting and crevice corrosion in low pH, high chloride oxidizing environments. The corrosion resistance of Alloy 22 is due to a passive film on the alloy surface. For Alloy 22, the uniform corrosion rate is very low in a wide range of solutions.1,2 The corrosion rate of Alloy 22 in brine solution decreases with increasing immersion time, and the corrosion rate is less than 30 nm/year after more than 250 days of immersion in highly concentrated brine solutions at 100°C.1 Localized corrosion is an important degradation mode to be evaluated for the corrosion performance of Alloy 22 over long exposure periods, and it has been examined by a number of researchers.3-13 Many factors affecting the localized corrosion behavior of Alloy 22 have been studied, such as the effects of Cl − and oxyanions, 3,4,[14][15][16] the effects of potential and temperature, 5,17 and the propagation and stifling of the crevice corrosion. 5,9,18,19 During the crevice corrosion process, corrosion products are formed. Corrosion products can exist as gas phase, such as hydrogen, soluble species, and insoluble corrosion precipitations. The composition and structure of the corrosion products give evidence to the discernment of the corrosion propagation and arrest processes. The insoluble corrosion products formed in the crevice can increase the ohmic resistance, and they can also affect transport in solution. The increase in ohmic resistance changes the potential distribution in the cre...

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Crevice Corrosion on Ni-Cr-Mo Alloys

Cited by 19 publications

References 0 publications

Characterization of surface composition on Alloy 22 in neutral chloride solutions

Characterization of surface composition on Alloy 22 in neutral chloride solutions

Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

Characterization of the Corrosion Products of Crevice Corroded Alloy 22

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