Phosphate Inhibition Effect on Chloride-Induced Crevice Corrosion of Alloy 22

2012 ◽  
Vol 1475 ◽  
Author(s):  
Marcela Miyagusuku ◽  
Ricardo M. Carranza ◽  
Raul B. Rebak
Keyword(s):  
Crevice Corrosion ◽  
Concentration Ratio ◽  
Localized Corrosion ◽  
Potential Range ◽  
Nacl Solution ◽  
Electrochemical Tests ◽  
Inhibition Effect ◽  
Phosphate Ions ◽  
Alloy 22 ◽  
Phosphate Inhibition

ABSTRACTAlloy 22 has been extensively studied regarding its crevice corrosion (CC) resistance both in pure chloride solutions and in solutions containing different oxyanions that may act as inhibitors of crevice corrosion. The scope of this work was to study the general and localized corrosion behavior of Alloy 22 when phosphate ions were added to a 1 M NaCl solution at 90°C. Results from the electrochemical tests indicate that the size of the passive potential range and the localized corrosion repassivation potential value increased in the presence of phosphate ions. Results from creviced specimens showed a strong inhibition effect of phosphate ions on the chloride induced crevice corrosion of Alloy 22. The critical molar concentration ratio (RCRIT = [phosphate]/[Cl]) to inhibit crevice corrosion was 0.3.

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 Inhibition Effect of Tartrate Ions on the Localized Corrosion of Steel in Pore Solution at Different Chloride Concentrations

Buildings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 105
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Denny Coffetti ◽  
Luigi Coppola ◽  
Tommaso Pastore
Keyword(s):  
Competitive Adsorption ◽  
Pore Solution ◽  
Chloride Concentration ◽  
Chelating Agent ◽  
Localized Corrosion ◽  
Ferric Ions ◽  
Electrochemical Tests ◽  
Inhibition Effect ◽  
Passive Current ◽  
Corrosion Of Steel

The aim of this work is the evaluation of the inhibition effect of tartrate ions with respect to the localized corrosion of steel reinforcements in alkaline solution as a function of the concentration of chlorides ions. Weight loss tests and electrochemical tests were carried out in saturated Ca(OH)2 solution with NaOH at pH 12.7 and 13.2. The results only evidence a slight inhibition effect at pH 12.7, whereas at pH 13.2 the pitting onset is inhibited also for chloride concentration up to 3 M. Tartaric acid is a dicarboxylic acid with nucleophile substituents, which can act as a chelating agent both adsorbing on the surface of the passive film and forming a soluble complex with ferrous and ferric ions. Tartrate causes an increase in the passive current density but it prevents the depassivation of carbon steel due to the action of chlorides, thus preventing pitting initiation due to the competitive adsorption on metal surface.

scholarly journals Crevice Repassivation Potential of Alloy 22 in High-Nitrate Dust Deliquescence Type Environments

2007 ◽  
Author(s):  
Tiangan Lian ◽  
Gregory E. Gdowski ◽  
Phillip D. Hailey ◽  
Raul B. Rebak
Keyword(s):  
Aqueous Solutions ◽  
Crevice Corrosion ◽  
Anodic Behavior ◽  
Nitrate Ion ◽  
Electrochemical Tests ◽  
Desert Dust ◽  
Nitrate Ions ◽  
Alloy 22 ◽  
Low Humidity ◽  
High Chloride

The nitrate ion (NO3−) is an inhibitor for crevice corrosion of Alloy 22 (N06022) in chloride (Cl−) aqueous solutions. Naturally formed electrolytes may contain both chloride and nitrate ions. The higher the ratio R = [NO3−]/[Cl−] in the solution the stronger the inhibition of crevice corrosion. Atmospheric desert dust contains both chloride and nitrate salts, generally based on sodium (Na+) and potassium (K+). Some of these salts may deliquescence at relatively low humidity at temperatures on the order of 150°C and higher. The resulting deliquescent brines are highly concentrated and especially rich in nitrate. Electrochemical tests have been performed to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 150°C at ambient atmospheres. Naturally formed brines at temperatures higher than 120°C do not induce crevice corrosion in Alloy 22 because they contain high levels of nitrate. The inhibitive effect of nitrate on crevice corrosion is still active for temperatures higher than 100°C.

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

2006 ◽  
Author(s):  
Gabriel O. Ilevbare ◽  
Robert A. Etien ◽  
John C. Estill ◽  
Gary A. Hust ◽  
Ahmet Yilmaz ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Crevice Corrosion ◽  
Silver Chloride ◽  
Current Work ◽  
Anodic Behavior ◽  
Chloride Solutions ◽  
Electrochemical Tests ◽  
Alloy 22 ◽  
High Chloride

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 +0.5 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.

General Corrosion Behavior of N06022 in Super Concentrated Brines at Temperatures Higher than 100°C

2008 ◽  
Vol 1124 ◽  
Author(s):  
Raul B. Rebak
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Short Term ◽  
Corrosion Resistant ◽  
Electrochemical Tests ◽  
Alloy 22 ◽  
Nickel Based Alloy ◽  
Anions And Cations

AbstractAlloy 22 (N06022) is a highly corrosion resistant nickel based alloy. Extensive research has been conducted in the last eight years on the corrosion behavior of Alloy 22, mainly regarding its resistance to localized corrosion. Less attention has been paid to the general corrosion resistance in highly concentrated brines that may result from the deliquescence of salts contained in dust. Salts such as mixtures of NaCl, KCl, CaCl2, NaNO3, and KNO3 may deliquesce at temperatures above 100°C through absorption of moisture from the air. Electrochemical tests were used to assess the general corrosion behavior of Alloy 22 in brines with chloride and nitrate concentrations ranging from 8 molal to 100 molal in the temperature range 100 to 160°C. The effect of mixed anions and cations was also studied. Results show that, even for short-term immersion periods, the corrosion rate of Alloy 22 in high temperatures super concentrated brines is generally below 10 μm/year.

Effect of [HCO3-+CO32−[ on Corrosion Crevice Repassivation Potential of Carbon Steel in Simulated Bentonite Environment

1995 ◽  
Vol 412 ◽  
Author(s):  
Takanori Fukuda ◽  
Masatsune Akashi
Keyword(s):  
Carbon Steel ◽  
Crevice Corrosion ◽  
Localized Corrosion ◽  
Potential Range ◽  
Free Corrosion Potential ◽  
Critical Potential ◽  
Corrosion Susceptibility ◽  
The Relationship ◽  
Critical Ph ◽  
Critical Initiation

AbstractIn order to evaluate the localized corrosion susceptibility of carbon steel in water containing bentonite, the critical pH for depassivation, pHd, the critical potential for crevice corrosion, ERCREV, and the free corrosion potential, Esp, were determined in simulated aqueous solutions of 1 to 100 mmol/L [HCO3- - CO32−], 1 to 1000 mmo!/L [NaCI], and pH of 7 to 12. The Following results were obtained; 1)ER, CREV. increases with increasing [HCO3− CO32−] concentration. The relationship can be described as a function of the ratio of [CI-I HCO3−- CO32−], 2)The Esp increases with increasing pH in the passive region, and 3)ThepHd shows [HCO3− - CO32−] concentration dependency. This paper also discusses the relationship between critical initiation potential for crevice corrosion of carbon steel, [CI-], and [HCO3− CO32−] anion. The crevice corrosion that occurs on passivated metals and alloys is characterized by determinable critical initiation potential that can be induced in a potential range nobler than its critical potential.

Inhibition Mechanism of Phosphate Ions on Chloride-Induced Crevice Corrosion of Alloy 22

CORROSION ◽  
10.5006/1373 ◽  
2015 ◽  
Vol 71 (5) ◽  
pp. 574-584 ◽  
Author(s):  
Marcela Miyagusuku ◽  
Ricardo M. Carranza ◽  
Raul B. Rebak
Keyword(s):  
Crevice Corrosion ◽  
Inhibition Mechanism ◽  
Phosphate Ions ◽  
Alloy 22

A Critical Appraisal of Some Popular Laboratory Electrochemical Tests for Predicting the Localized Corrosion Resistance of Stainless Alloys in Sea Water

CORROSION ◽  
1972 ◽  
Vol 28 (8) ◽  
pp. 283-291 ◽  
Author(s):  
B. E. WILDE
Keyword(s):  
Crevice Corrosion ◽  
Anodic Polarization ◽  
Sea Water ◽  
Chloride Ion ◽  
Localized Corrosion ◽  
Cyclic Polarization ◽  
Pitting Potential ◽  
Electrochemical Tests ◽  
The Difference ◽  
Pit Initiation

Abstract Evidence is presented to demonstrate that although the critical pitting potential is qualitatively related to the resistance of a material to passivity breakdown by pit initiation, it is of questionable value in predicting the corrosion performance off a structure containing crevices. Experiments conducted on a 30Cr-3Mo-Fe alloy indicated total immunity to passivity breakdown by pit initiation during anodic polarization in 1M NaCl and under freely corroding conditions in acidified 10% FeCl3. However, on specimens containing an artificial crevice, passivity breakdown by crevice corrosion initiation was observed in the same two media. The long term implications of these data were confirmed by 16 month immersion tests in sea water, where severe crevice attack was noted equal in extent to that observed on A9SS Types 304 and 316 stainless steels whose pit initiation properties were considerably inferior to those of the 30Cr-3Mo-Fe alloy. The results of cyclic potentiodynamic anodic polarization experiments conducted on A8S1 Type 430 stainless steel are presented to demonstrate that the so called protection potential, Ep, is not a unique material parameter. It is shown that Ep varies in a semi logarithmic manner with the amount of localized attack induced by polarization; that is, with the chemistry changes in the growing pit caused by hydrolysis of corrosion products and chloride ion buildup in the pit cavities. On this basis, it is concluded that Ep data (however determined) cannot be used alone as a criteria for protection against the propagation of pre-existing pits or crevices in an engineering structure. Based on cyclic polarization procedures, a method of assessing the susceptibility and resistance of an alloy to crevice corrosion is suggested. It is shown that, for alloys which initiate pits during anodic polarization, the magnitude of the “difference potential” (Ec-Ep) is related to the crevice corrosion weight loss. For alloys that have no critical pitting potential, the presence of hysteresis during cyclic polarization with an artificial crevice indicates susceptibility to crevice 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.

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