Effect of Nitrate on the Repassivation Potential of Alloy 22 in Chloride-Containing Environments

Ilevbare, G. O.; King, Kenneth J.; Gordon, Steven R.; Elayat, H A; Gdowski, G.E.; Gdowski, T. S.E.

doi:10.1149/1.2104067

Cited by 51 publications

(53 citation statements)

References 29 publications

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“…Brossia andKelly 1998, Ilevbare et al 2005]. This has been demonstrated for Alloy 22 in the temperature range 60 to 100°C for aqueous solutions of 1, 3.5 and 6 molal Cl [Ilevbare et al 2005]. In the Ilevbare et al study, localized corrosion inhibition was observed at 60°C with nitrate to chloride ratio of 0.15 and at 100°C with a ratio of 0.5…”

Section: Introductionmentioning

confidence: 90%

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Alloy 22 Localized Corrosion Susceptibility In Aqueous Solutions Of Chloride And Nitrate Salts Of Sodium And Potassium At 110 - 150?C

Felker¹,

Hailey²,

Lian³

et al. 2006

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Section: Introductionmentioning

confidence: 90%

“…LLNL has shown that nitrate is an effective inhibitor of chloride induced localized corrosion of Alloy 22 in the temperature range 60 -100°C and for concentrations of 1, 3.5 and 6 molal Cl [Ilevbare et al 2005]. Localized corrosion inhibition was observed at 60°C with nitrate to chloride ratio of 0.15 and at 100°C with a ratio of 0.5.…”

Section: Corrosionmentioning

confidence: 98%

Alloy 22 Localized Corrosion Susceptibility In Aqueous Solutions Of Chloride And Nitrate Salts Of Sodium And Potassium At 110 - 150?C

Felker¹,

Hailey²,

Lian³

et al. 2006

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“…13 Before mounting them onto the metallic specimens, the CF were covered with PTFE tape to ensure a tight crevicing gap. [14][15][16] The specimens had a ground finish of 600grit paper. There are two types of specimens mentioned in this work: (1) The as-received wrought mill annealed (MA) and (2) the solution heat-treated (MA + SHT) which were annealed in air for 20 min at 1121°C and then water quenched.…”

Section: Methodsmentioning

confidence: 99%

“…2 The common acceptance criterion for the maximum allowed corrosion rate for Alloy 22 is 80 mpy or 2 mm/year. 15 After the corrosion immersion tests each specimen was thoroughly inspected under optical microscopy (stereomicroscope). Results are given in Table 2.3.…”

Section: +mentioning

confidence: 99%

Localized Corrosion of Alloy 22 -Fabrication Effects-

Rebak¹

2005

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EXECUTIVE SUMMARYThis report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats A of Alloy 22 for container fabrication.Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual repository environments in Yucca Mountain. For example, to determine the intergranular attack in the heat affected zone of a weldment, tests are conducted in boiling acidic and oxidizing solutions according to ASTM standards. These solutions are used to compare the behavior of differently treated metallic coupons. Similarly for electrochemical tests many times pure sodium chloride or calcium chloride solutions are used. Pure chloride solutions are not representative of the repository environment.1. Surface Stress Mitigation: When metallic plates are welded, for example using the Gas Tungsten Arc Welding (GTAW) method, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to comparatively test the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results from both immersion and electrochemical corrosion tests show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied. Behavior of Specimens from a Mockup container:Alloy 22 has been extensively tested for general and localized corrosion behavior both in the wrought and annealed condition and in the as-welded condition. The specimens for testing were mostly prepared from flat plates of material. It was important to determine if the process of fabricating a full diameter Alloy 22 container will affect the corrosion performance of this alloy. Specimens were prepared directly from a fabricated container and tested for corrosion resistance. Results show that both the anodic corrosion behavior and the localized corrosion resistance of specimens prepared from a welded fabricated container were the same as from flat welded plates. That is, rolling and welding plates using industrial practices do not hinder the corrosion resistant of Alloy 22.3. Effect of Black Annealing Oxide Scale: The resistance of Alloy 22 to localized corrosion, mainly crevice corrosion, has been extensively investigated in the last few years. This was done mostly using freshly polished specimens. At this time it was important to address the effect an oxide film or scale that forms du...

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“…'-I2 It has been reported that Alloy 22 may suffer localized corrosion such as crevice corrosion when it is is also known that the presence of nitrate (NO3-) and other oxyanions in the solution minimizes or eliminates the susceptibility of Alloy 22 to crevice corrosion. 84031G- 23 The value of the ratio ([NO,-]/([Cl-]) has a strong effect of the susceptibility of Alloy 22 to crevice corrosion.…”

Section: Introductionmentioning

confidence: 99%

Anodic Behavior of Alloy 22 in High Nitrate Brines at Temperatures Higher Than 100c

LLEVBARE¹,

ESTILL²,

Yilmaz³

et al. 2006

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Alloy 22 (N06022) may be susceptible to crevice corrosion in chloride solutions. Nitrate acts as an inhibitor to crevice corrosion. Several papers have been published regarding the effect of nitrate on the corrosion resistance of Alloy 22 at temperatures 100°C and lower. However, very little is known about the behavior of this alloy in highly concentrated brines at temperatures above 100°C. In the current work, electrochemical tests have been carried out to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 160°C at ambient atmospheres. Even though Alloy 22 may adopt corrosion potentials in the order of + O S V (in the saturated silver chloride scale), it does not suffer crevice corrosion if there is high nitrate in the solution. That is, the inhibitive effect of nitrate on crevice corrosion is active for temperatures higher than 100°C.

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Effect of Nitrate on the Repassivation Potential of Alloy 22 in Chloride-Containing Environments

Cited by 51 publications

References 29 publications

Alloy 22 Localized Corrosion Susceptibility In Aqueous Solutions Of Chloride And Nitrate Salts Of Sodium And Potassium At 110 - 150?C

Alloy 22 Localized Corrosion Susceptibility In Aqueous Solutions Of Chloride And Nitrate Salts Of Sodium And Potassium At 110 - 150?C

Localized Corrosion of Alloy 22 -Fabrication Effects-

Anodic Behavior of Alloy 22 in High Nitrate Brines at Temperatures Higher Than 100c

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