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.

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.

The Development of a Mechanistic Basis for Modelling Fuel Dissolution and Container Failures Under Waste Vault Conditions

1988 ◽  
Vol 127 ◽  
Author(s):  
D. W. Shoesmith ◽  
S. Sunder ◽  
B. M. Ikeda ◽  
F. King
Keyword(s):  
Experimental Data ◽  
Titanium Alloys ◽  
Nuclear Waste ◽  
Waste Disposal ◽  
Predictive Models ◽  
Crevice Corrosion ◽  
Electrochemical Techniques ◽  
Short Term ◽  
Mechanistic Basis ◽  
Radionuclide Release

ABSTRACTDue to the long containment periods required for radionuclides in a nuclear waste disposal vault, the justification that a particular containment system is acceptable will be based on relatively short-term experimental data used to support predictive models. To justify this approach, we must possess a sound mechanistic understanding of processes such as fuel dissolution, radionuclide release and container corrosion. Since these processes are driven by oxidants in the vault, it is natural to study them by electrochemical techniques. In this paper, we have reviewed a number of electrochemical methods used in the study of waste vault reactions. More detailed descriptions are given of the development of predictive models for the dissolution of UO2, the crevice corrosion of titanium alloys and the uniform dissolution of copper.

Oxygen Absorption Kinetics of Sheets and Films Containing a Commercial Iron-based Oxygen Scavenger

2009 ◽  
Vol 15 (2) ◽  
pp. 159-168 ◽  
Author(s):  
M.J. Galotto ◽  
S.A. Anfossi ◽  
A. Guarda
Keyword(s):  
Relative Humidity ◽  
Kinetic Parameters ◽  
Oxygen Absorption ◽  
Absorption Kinetics ◽  
Oxygen Scavenger ◽  
Arrhenius Behavior ◽  
Oxygen Scavengers ◽  
Iron Based ◽  
Empirical Growth ◽  
Kinetics Of

Absorption kinetics of three different forms of the same iron-based oxygen scavenger were studied. Oxygen scavengers were used as pellet, sheet, and film materials. Two scavenger concentrations were used for sheet and film forms. Scavenger samples were analyzed at 75 or 100% relative humidities and stored at 5, 15, and 25°C. Oxygen concentration in the headspace was measured as a function of time. Absorption kinetics was best described by the Chapman-Richards empirical growth model rather than by a first-order reaction. Arrhenius behavior was observed for variations in the final absorption rate with temperature. Absorption capacities, final absorption rates, and activation energies were evaluated and discussed. Scavenger concentration, relative humidity, and temperature effects on kinetic parameters were studied for each experimental condition. Temperature was the most important factor that affected kinetic parameters. At the relative humidity levels studied, any important effect on kinetic parameters was not observed, except on absorption capacities.

Effects of Stress and Plastic Deformation on the Corrosion of Steel

CORROSION ◽  
1970 ◽  
Vol 26 (5) ◽  
pp. 189-199 ◽  
Author(s):  
W. D. FRANCE
Keyword(s):  
Plastic Deformation ◽  
Electrochemical Techniques ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Potential Range ◽  
Chemical Corrosion ◽  
Effects Of Ph ◽  
Current Densities ◽  
The Stability

Abstract The rate and type of corrosion exhibited by mild steel in the annealed, stressed, and plastically deformed state have been investigated. Precise electrochemical techniques provided potential and polarization data to supplement the results of chemical corrosion tests. Experiments were conducted in 0.6M NH4NO3 solutions in which steel exhibits active-passive dissolution behavior as well as localized corrosion. At active potentials, the anodic polarization curves for annealed and deformed specimens were nearly identical, with only slight increases in current densities for the deformed steel. Results at passive potentials demonstrated that increased plastic deformation can markedly decrease the passive potential range, the stability of passivity, and the ability to passivate. At certain passive potentials, the deformed steel exhibited current densities that were 400 times greater than those for annealed steel. The effects of pH, chloride ions, and crevices on the corrosion of deformed steel were examined in detail. The differences between the dissolution behavior of annealed and deformed steel were most distinctive in the approximate pH range of 3 to 6. This work is relevant to the understanding of the initiation of localized corrosion and to anodic protection.

Localized Corrosion of UNS A95052 Aluminum Alloy for Application in Multi-Effect Desalinator Plants

CORROSION ◽  
10.5006/2815 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 1023-1032
Author(s):  
Dannisa R. Chalfoun ◽  
Mariano A. Kappes ◽  
Mauricio Chocrón ◽  
Raul B. Rebak
Keyword(s):  
Aluminum Alloy ◽  
Crevice Corrosion ◽  
Low Cost ◽  
Localized Corrosion ◽  
Complete Evaluation ◽  
Electrochemical Tests ◽  
Metal Plates ◽  
Different Temperatures ◽  
Partially Occluded ◽  
Desalination Plants

Aluminum alloy UNS A95052 (AA5052) is very attractive for desalination applications because of its good corrosion resistance in seawater at temperatures up to 125°C, low cost, good thermal conductivity, and non-toxicity of its corrosion products. The pitting corrosion potential, Epit, and the pit repassivation potential, Er,pit, of AA5052 were measured in deaerated 65,000 ppm sodium chloride (NaCl) solutions at 30°C, 60°C, and 85°C. Epit decreased with temperature, in accord with literature results. Er,pit was a function of anodic charge passed during pit growth stage. A complete evaluation of suitability of this alloy from a corrosion perspective requires also studies of crevice corrosion at different temperatures, considering that multi-plate designs of desalinators have metal plates in contact with rubber gaskets and seals. Cyclic potentiodynamic polarization was used to estimate crevice repassivation potentials, Er,crev, at 30°C, 60°C, and 85°C, in specimens with an attached rubber O-ring as a crevice former. This crevice former simulated the partially occluded geometry expected in desalination plants. Stable crevice corrosion potentials, Ecrev, were similar to Epit, and, when polarized to a similar anodic charge density, Er,crev were similar to Er,pit. Based on this result, from a corrosion perspective, the presence of crevices in the desalination plant is not expected to present an additional risk during operation of the plant. Electrochemical tests were also performed in saturated AlCl3 solutions to explain the results using Galvele’s localized acidification model.

scholarly journals Corrosion Resistance of Hard Coat Anodized AA 6061 in Citric–Sulfuric Solutions

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 601
Author(s):  
José Cabral-Miramontes ◽  
Citlalli Gaona-Tiburcio ◽  
Francisco Estupinán-López ◽  
María Lara-Banda ◽  
Patricia Zambrano-Robledo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Sulfuric Acid Electrolyte ◽  
Cyclic Potentiodynamic Polarization ◽  
Anodization Process ◽  
Current Densities ◽  
Corrosive Environments ◽  
Sulfuric Acid Solutions

Aluminum is a material widely used in aeronautical and transport industries due to its excellent mechanical and corrosion resistance properties. Unfortunately, aluminum alloys are susceptible to corrosion, which limits their use in some corrosive environments. The aim of this work is to characterize hard coat film fabricated by anodizing in a citric–sulfuric acid system using electrochemical techniques. The anodization process was carried out using an aluminum alloy AA 6061 anodization bath: a mix of citric and sulfuric acid solutions were used. For the anodizing process, two current densities were used, 1 and 7.2 A·cm−2. Anodized specimens obtained under different conditions were exposed to a 3.5 wt.% NaCl solution, and their electrochemical behavior was studied by electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) according to ASTM G106-15 and ASTM G5-13, respectively. Scanning electron microscopy (SEM) was employed to determinate the morphology and thickness of coatings. The results showed improved corrosion resistance in 6061 aluminum anodized in citric–sulfuric acid electrolyte compared to those anodized in sulfuric acid solution.

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