Determination of Crevice Corrosion Susceptibility of Alloy 22 Using Different Electrochemical Techniques

2010 ◽  
Vol 1265 ◽  
Author(s):  
Mauricio Rincon Ortiz ◽  
Martín A. Rodríguez ◽  
Ricardo M. Carranza ◽  
Raul B. Rebak
Keyword(s):  
Crevice Corrosion ◽  
Electrochemical Techniques ◽  
Localized Corrosion ◽  
Repassivation Potential ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization ◽  
Corrosion Susceptibility ◽  
High Level Nuclear Waste ◽  
High Level

AbstractAlloy 22 belongs to the Ni-Cr-Mo family and it is highly resistant to general and localized corrosion. It may suffer crevice corrosion in aggressive environmental conditions. This alloy has been considered as a corrosion-resistant barrier for high-level nuclear waste containers. It is assumed that localized corrosion may occurs when the corrosion potential (ECORR) is equal or higher than the crevice corrosion repassivation potential (ER,CREV). The latter is measured by means of different electrochemical techniques using artificially creviced specimens. These techniques include cyclic potentiodynamic polarization (CPP) curves, Tsujikawa-Hisamatsu electrochemical (THE) method or other non-standard methods, such as the PD-GS-PD technique.The aim of the present work was to determine reliable critical or protection potentials for crevice corrosion of Alloy 22 in pure chloride solutions at 90°C. Conservative methodologies (which include extended potentiostatic steps) were applied for determining protection potentials below which crevice corrosion cannot initiate and propagate. Results from PD-GS-PD technique were compared with those from these methodologies in order to assess their reliability. Results from the CPP and the THE methods were also considered for comparison. The repassivation potential resulting from the PD-GS-PD technique was conservative and reproducible, and it did not depend on the amount of previous crevice corrosion propagation.

Effect of Inhibiting Oxyanions on the Localized Corrosion Susceptibility of Waste Package Container Materials

2004 ◽  
Vol 824 ◽  
Author(s):  
D.S. Dunn ◽  
L. Yang ◽  
C. Wu ◽  
G.A. Cragnolino
Keyword(s):  
Radioactive Waste ◽  
Crevice Corrosion ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Waste Package ◽  
High Level Radioactive Waste ◽  
License Application ◽  
Alloy 22 ◽  
Corrosion Susceptibility ◽  
High Level

AbstractThe DOE is currently preparing a license application for the permanent disposal of high level radioactive waste at Yucca Mountain, Nevada. The proposed design of waste packages for the disposal of high level radioactive waste consists of an outer container made of Alloy 22, a corrosionresistant Ni-Cr-Mo-W alloy, surrounding an inner container made of Type 316 nuclear grade stainless steel. Under conditions where passivity is maintained, the uniform corrosion rate of Alloy 22 is slow and long waste package lifetimes are projected. However, the initiation of localized corrosion such as pitting or crevice corrosion may decrease waste package lifetimes. In this study the crevice corrosion susceptibility of Alloy22 was determined in chloride solutions with additions of oxyanions that are present in the groundwater at the potential repository site. When present in sufficient concentrations relative to chloride, nitrate, carbonate, bicarbonate, and sulfate inhibited pitting and crevice corrosion of Alloy 22.

The Use of Repassivation Potential in Predicting The Performance of High-Level Nuclear Waste Container Materials

1994 ◽  
Vol 353 ◽  
Author(s):  
Narasi Sridhar ◽  
Darrell Dunn ◽  
Gustavo Cragnolino
Keyword(s):  
Field Tests ◽  
Localized Corrosion ◽  
High Level Waste ◽  
Repassivation Potential ◽  
Waste Container ◽  
Highly Sensitive ◽  
Plant Equipment ◽  
Robust Parameter ◽  
High Level Nuclear Waste ◽  
High Level

AbstractLocalized corrosion in aqueous environments forms an important bounding condition for the performance assessment of high-level waste (HLW) container materials. A predictive methodology using repassivation potential is examined in this paper. It is shown, based on long-term (continuing for over 11 months) testing of alloy 825, that repassivation potential of deep pits or crevices is a conservative and robust parameter for the prediction of localized corrosion. In contrast, initiation potentials measured by short-term tests are non-conservative and highly sensitive to several surface and environmental factors. Corrosion data from various field tests and plant equipment performance are analyzed in terms of the applicability of repassivation potential. The applicability of repassivation potential for predicting the occurrence of stress corrosion cracking (SCC) and intergranular corrosion in chloride containing environments is also examined.

Environmental Effects on Localized Corrosion of a High-Level Nuclear Waste Container Material

1990 ◽  
Vol 212 ◽  
Author(s):  
N. Sridhar ◽  
G. Cragnolino ◽  
W. Machowski
Keyword(s):  
Localized Corrosion ◽  
A Value ◽  
Waste Container ◽  
Electrochemical Parameters ◽  
Cyclic Potentiodynamic Polarization ◽  
High Level Nuclear Waste ◽  
Full Factorial Experimental Design ◽  
High Level ◽  
Full Factorial ◽  
High Chloride

ABSTRACTThe effect of environmental variables on the localized corrosion behavior of alloy 825 is examined in this paper. Cyclic, potentiodynamic polarization tests based on a two-level, full factorial experimental design were conducted. An index incorporating both the visual and scanning electron microscope examinations of localized corrosion and the electrochemical parameters was used for the statistical analysis. The analysis showed that chloride is the single most important promoter of localized corrosion, while nitrate was the single most important inhibitor. Fluoride was a weak inhibitor, especially at low chloride levels. Sulfate was a weak promoter, especially at high chloride levels. Temperature did not have a significant effect within the chloride levels examined. Separate experiments indicated that silicon, added as metasilicate, did not have any significant effect on localized corrosion. The adverse effect of chloride was observed at concentrations as low as 100 ppm. Addition of H2O2 increased the corrosion potential of alloy 825 to a value above the repassivation potential observed in the 300 ppm chloride solution.

Crevice Corrosion in Oxygen Scavenger Injection System

2021 ◽  
Author(s):  
Amela Keserovic ◽  
Øystein Birketveit
Keyword(s):  
Crevice Corrosion ◽  
Electrochemical Techniques ◽  
Localized Corrosion ◽  
Injection System ◽  
Recent Experience ◽  
Oxygen Scavenger ◽  
Short Term ◽  
Oxygen Scavengers ◽  
Cyclic Potentiodynamic Polarization ◽  
Stainless Steel 316

Abstract Biulfite-based oxygen scavengers (OS) have been traditionally used in oilfields to reduce corrosion resulting from dissolved oxygen. Recent experience with a leakage in OS-A oxygen scavenger injection system has shown that the same production chemicals in neat form can cause corrosion themselves, specifically – crevice corrosion. In this paper a tendency of three bisulfite-based oxygen scavengers to initiate crevice corrosion on 316 stainless steel (316 SS) was evaluated by means of long-term exposure tests and short-term electrochemical techniques; cyclic potentiodynamic polarization (CPP) and Tsujikawa–Hisamatsu electrochemical method (THE). The testing was performed at ambient temperature and pressure to mimic the topside injection system conditions. The tested oxygen scavengers differed in bisulfite concentration (OS-A, 341 g/L; OS-B, 328 g/L; OS-C, 750 g/L) and pH (pH 3, 6 and 5, respectively). Two 316 SS coupons were attached together using elastomer O-rings to simulate steel-to-steel crevice between. The surface of the coupons was examined at 50x magnification after the test termination. The results presented herein showed that 30-day long exposure tests were not long or aggressive enough to provide information about the corrosivity of the chemicals in terms of crevice corrosion. Instead, the combination of short-term electrochemical techniques proved to be useful in explaining a possible cause of the leakage in OS-A injection system and allowed ranking of the products based on their tendency to initiate localized corrosion.

Corrosion Processes Affecting the Performance of Alloy 22 as a High-Level Radioactive Waste Container Material

2000 ◽  
Vol 663 ◽  
Author(s):  
G.A. Cragnolino ◽  
D.S. Dunn ◽  
Y.-M. Pan ◽  
O. Pensado
Keyword(s):  
Radioactive Waste ◽  
Electrochemical Techniques ◽  
Department Of Energy ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Uniform Corrosion ◽  
High Level Radioactive Waste ◽  
Waste Container ◽  
Alloy 22 ◽  
High Level

ABSTRACTAlloy 22 is the material preferred by the U.S. Department of Energy for the waste package outer container for geological disposal of high-level radioactive waste at the proposed site in Yucca Mountain, Nevada. Alloy 22 is considered to be extremely resistant to various modes of aqueous corrosion over broad ranges of temperature, pH, and concentration of anionic and oxidizing species. Uniform corrosion under passive dissolution conditions, localized corrosion in the form of crevice corrosion, and stress corrosion cracking are discussed on the basis of experimental results obtained with mill annealed, thermally treated, and welded specimens using electrochemical techniques. The approach developed for long-term performance prediction, including the use of empirically derived parameters for assessing localized corrosion and the modeling of the passive dissolution behavior, is described.

scholarly journals Determination of the Crevice Repassivation Potential of Alloy 22 by a Potentiodynamic-Galvanostatic-Potentiostatic Method

2004 ◽  
Author(s):  
Kenneth J. Evans ◽  
Lana L. Wong ◽  
Rau´l B. Rebak
Keyword(s):  
Chloride Concentration ◽  
Localized Corrosion ◽  
Rapid Screening ◽  
Corrosion Attack ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization ◽  
High Chloride Concentration ◽  
Nickel Based Alloy ◽  
High Chloride

Alloy 22 (N06022) is a nickel-based alloy highly resistant to corrosion. In some aggressive conditions of high chloride concentration, temperature and applied potential, Alloy 22 may suffer crevice corrosion, a form of localized corrosion. There are several electrochemical methods that can be used to determine localized corrosion in metallic alloys. One of the most popular for rapid screening is the cyclic potentiodynamic polarization (CPP). This work compares the results obtained by measuring the localized corrosion resistance of Alloy 22 using both the CPP and the more cumbersome Tsujikawa-Hisamatsu Electrochemical (THE) method. The electrolytes used were 1 M NaCl and 5 M CaCl2, both at 90°C. Results show that similar repassivation potentials were obtained for Alloy 22 using both methods. That is, in cases where localized corrosion is observed using the faster CPP method, there is no need to use the THE method since it takes ten times longer to obtain comparable results in spite of the mode of corrosion attack is sometimes different in the tested specimens.

Localized Corrosion Susceptibility of Alloy 22 as a Waste Package Container Material

2002 ◽  
Vol 713 ◽  
Author(s):  
Gustavo A. Cragnolino ◽  
Darrell S. Dunn ◽  
Yi-Ming Pan
Keyword(s):  
Chloride Concentration ◽  
Department Of Energy ◽  
Localized Corrosion ◽  
Waste Package ◽  
Alloy 22 ◽  
Microstructural Effects ◽  
Anionic Species ◽  
Corrosion Susceptibility ◽  
High Level ◽  
Increasing Temperature

ABSTRACTAlloy 22 is the material preferred by the U.S. Department of Energy for the waste package outer container for geological disposal of high-level radioactive waste at the proposed repository site in Yucca Mountain, Nevada. The susceptibility of Alloy 22 to localized corrosion is an important consideration in the evaluation of the waste package behavior and the assessment of the overall performance of the proposed repository. The effects of the environment chemical composition and temperature on localized corrosion susceptibility were examined by measuring the repassivation potential for crevice corrosion in chloride-containing solutions at temperatures ranging from 80 to 150°C. The effect of potentially inhibiting anionic species, such as nitrate, was also determined. In addition to the mill annealed material, tests were conducted on both welded and thermally aged material to evaluate microstructural effects related to container fabrication processes. The resistance of Alloy 22 to localized corrosion decreased with increasing temperature and chloride concentration. Welding and thermal aging also decreased the localized corrosion resistance of the alloy.

scholarly journals Repassivation Potential of Alloy 22 in Chloride plus Nitrate Solutions using the Potentiodynamic-Galvanostatic-Potentiostatic Method

2006 ◽  
Vol 985 ◽  
Author(s):  
Kenneth J. Evans ◽  
Raul B. Rebak
Keyword(s):  
Sodium Chloride ◽  
Potentiodynamic Polarization ◽  
Crevice Corrosion ◽  
Potassium Nitrate ◽  
Potentiostatic Method ◽  
Repassivation Potential ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization ◽  
Nitrate Solutions

AbstractIn general, the susceptibility of Alloy 22 to suffer crevice corrosion is measured using the Cyclic Potentiodynamic Polarization (CPP) technique. This is a fast technique that gives rather accurate and reproducible values of repassivation potential (ER1) in most cases. In the fringes of susceptibility, when the environment is not highly aggressive, the values of repassivation potential using the CPP technique may not be highly reproducible, especially because the technique is fast and because transpassive corrosion may influence or mask the nucleation and propagation of crevice corrosion. To circumvent this, the repassivation potential of Alloy 22 was measured using a slower method that combines Potentiodynamic-Galvanostatic-Potentiostatic steps (called here the Tsujikawa-Hisamatsu Electrochemical or THE method). The THE method applies the charge to the specimen in a more controlled way, which may give more reproducible repassivation potential values, especially when the environment is not aggressive. The values of repassivation potential of Alloy 22 in sodium chloride plus potassium nitrate solutions were measured using the THE and CPP methods. Results show that both methods yield similar values of repassivation potential, especially under aggressive conditions.

scholarly journals Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

2008 ◽  
Vol 1107 ◽  
Author(s):  
Raul B. Rebak ◽  
Gabriel O. Ilevbare ◽  
Ricardo M. Carranza
Keyword(s):  
Sodium Chloride ◽  
Calcium Chloride ◽  
Crevice Corrosion ◽  
Nitrate Concentration ◽  
Chloride Concentration ◽  
Chloride Solutions ◽  
Sodium Chloride Solutions ◽  
Repassivation Potential ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization

AbstractA comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75°C and at 90°C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions

Localized Corrosion Susceptibility of Alloy 22 in Chloride Solutions: Part 1—Mill-Annealed Condition

CORROSION ◽  
2005 ◽  
Vol 61 (11) ◽  
pp. 1078-1085 ◽  
Author(s):  
D. S. Dunn ◽  
Y-M. Pan ◽  
L. Yang ◽  
G. A. Cragnolino
Keyword(s):  
Localized Corrosion ◽  
Annealed Condition ◽  
Chloride Solutions ◽  
Alloy 22 ◽  
Corrosion Susceptibility
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