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

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.

scholarly journals Effect of Chemistry Variations of Wrought N06022 Plates on the Repassivation Potential in 1 M NaCl at 90°C

2008 ◽  
Author(s):  
Kevin G. Mon ◽  
Raul B. Rebak
Keyword(s):  
Chemical Composition ◽  
Potentiodynamic Polarization ◽  
Heat Treating ◽  
Weight Percent ◽  
Nacl Solution ◽  
Nickel Chromium ◽  
Repassivation Potential ◽  
Heat Treated ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization

ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022). The composition of each element is given in a range (e.g., the lowest content of Mo is specified as 12.5 weight percent and the highest as 14.5 weight percent. It is important to determine the dependence of Alloy 22 electrochemical behavior on the composition of the alloying elements as they vary from the lowest to the highest end of the ranges specified in ASTM B 575 standard. Seven heats of Alloy 22 plate were melted and processed. The plates were tested in the mill annealed (MA) and solution heat treated (SHT) condition. Cyclic potentiodynamic polarization tests were performed in 1 M NaCl solution at 90°C. Results show no influence of Alloy 22 chemistry variations or heat treating on the measured repassivation potential.

Technical Note: Syringe Cell for Electrochemical Testing

CORROSION ◽  
10.5006/2847 ◽  
2018 ◽  
Vol 74 (8) ◽  
pp. 847-850 ◽  
Author(s):  
A.M. Panindre ◽  
K.H. Chang ◽  
T. Weirich ◽  
G.S. Frankel
Keyword(s):  
Stainless Steel ◽  
Potentiodynamic Polarization ◽  
Crevice Corrosion ◽  
Electrochemical Cell ◽  
Technical Note ◽  
Counter Electrodes ◽  
Exposed Area ◽  
Cell Method ◽  
Electrochemical Testing ◽  
Cyclic Potentiodynamic Polarization

A very simple electrochemical cell for corrosion experiments has been developed using a syringe as the cell with the syringe plunger replaced by reference and counter electrodes. Because the exposed area is defined by a hanging droplet, no masking is required and thus no crevice corrosion forms. This cell therefore enables measurements of pitting potentials of metals that are susceptible to crevice corrosion. The method was validated by cyclic potentiodynamic polarization experiments on Type 304H stainless steel. Crevice or interfacial corrosion was not evident in multiple replicate specimens tested with the syringe cell method.

Using electrochemical methods to determine alloy 22’s crevice corrosion repassivation potential

JOM ◽  
2005 ◽  
Vol 57 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Kenneth J. Evans ◽  
Ahmet Yilmaz ◽  
S. Daniel Day ◽  
Lana L. Wong ◽  
John C. Estill ◽  
...  
Keyword(s):  
Crevice Corrosion ◽  
Electrochemical Methods ◽  
Repassivation Potential ◽  
Alloy 22

Crevice corrosion testing methods for measuring repassivation potential of alloy 22

2011 ◽  
Vol 46 (2) ◽  
pp. 129-133 ◽  
Author(s):  
C M Giordano ◽  
M Rincón Ortíz ◽  
M A Rodríguez ◽  
R M Carranza ◽  
R B Rebak
Keyword(s):  
Crevice Corrosion ◽  
Corrosion Testing ◽  
Testing Methods ◽  
Repassivation Potential ◽  
Alloy 22

Efficiency of inhibitors for chloride-induced crevice corrosion of Alloy 22

2012 ◽  
Vol 1475 ◽  
Author(s):  
Mauricio Rincón Ortíz ◽  
Martín A. Rodríguez ◽  
Ricardo M. Carranza ◽  
Raul B. Rebak
Keyword(s):  
High Temperatures ◽  
Crevice Corrosion ◽  
Carbonic Acid ◽  
Repassivation Potential ◽  
Alloy 22 ◽  
Engineered Barriers

ABSTRACTAlloy 22 is considered as a candidate for engineered barriers of nuclear repositories. Chloride is the only species present in groundwater that is able to promote crevice corrosion, if severe conditions such as high temperatures and a tight crevice are present. Other species present in groundwater have been shown to be inhibitors or non-detrimental species. The objective of this work was to evaluate the efficiency of different species potentially found in groundwaters as possible inhibitors of crevice corrosion of Alloy 22. The crevice corrosion repassivation potential of Alloy 22 was determined in chloride plus inhibitor solutions at 90ºC. The species tested as inhibitors were nitrate, sulfate, carbonate, bicarbonate, chromate, molybdate and tungstate. Nitrate was the most efficient among tested inhibitors. The carbonate was the only species of the carbonate / bicarbonate / carbonic acid equilibrium able to inhibit the chloride-induced crevice corrosion of Alloy 22. Sulfate, chromate and molybdate were moderately good inhibitors.

Effects of Test Methods on Crevice Corrosion Repassivation Potential Measurements of Alloy 22

CORROSION ◽  
2009 ◽  
Vol 65 (7) ◽  
pp. 449-460 ◽  
Author(s):  
X. He ◽  
B. Brettmann ◽  
H. Jung
Keyword(s):  
Crevice Corrosion ◽  
Test Methods ◽  
Repassivation Potential ◽  
Alloy 22

scholarly journals Effect of Salinity on Evaporation and the Water Cycle

2019 ◽  
Vol 3 (4) ◽  
pp. 255-262 ◽  
Author(s):  
Jude Iloabuchi Obianyo
Keyword(s):  
Sodium Chloride ◽  
Sodium Hydroxide ◽  
Ammonium Chloride ◽  
Magnesium Sulphate ◽  
Water Cycle ◽  
Nitrate Solution ◽  
Potassium Nitrate ◽  
Distilled Water ◽  
Consequent Reduction ◽  
Nitrate Solutions

This study is on the effect of salinity on evaporation from water bodies and probable influence on the water cycle. Five different salts were used in this study, different concentrations of Magnesium Sulphate, Sodium Hydroxide, Sodium Chloride, Ammonium Chloride and Potassium Nitrate solutions in the neighbourhood of 0.04, 0.08, 0.12, 0.16, 0.20 and 0.24 g/cm3 were prepared by dissolving 20, 40, 60, 80, 100 and 120 g weights of these salts in 500 cm3 of distilled water. The first evaporation can contained only 500 cm3 of distilled water and served as the control experiment. The solutions were introduced in evaporation cans each of capacity 700 cm3, stored under room temperature and evaporation allowed to take place. Evaporation from the cans were measured at 24 hours intervals for a period of 14 days. Results showed that in all salts, as salinity increases, evaporation is reduced. On the 10th day, evaporation retardation factors for Magnesium Sulphate, Sodium Hydroxide, Sodium Chloride, Ammonium Chloride and Potassium Nitrate were found to be 0.800, 0.490, 0.712, 0.820 and 0.822 respectively. Ratios of evaporation retardation factors were 1:1.6327 for Sodium hydroxide : Magnesium Sulphate; 1:1.4531 for  Sodium Hydroxide : Sodium Chloride; 1:1.6735 for  Sodium Hydroxide : Magnesium Sulphate; 1:1.4531 for Sodium Hydroxide: Sodium Chloride; 1:1.6327 for Sodium Hydroxide : Ammonium Chloride and 1:1.6776 for Sodium Hydroxide : Potassium Nitrate solutions. Highest evaporation took place in Potassium Nitrate solution at the ultimate concentration of 0.24 g/cm3, this was followed by Ammonium Chloride, Magnesium Sulphate, Sodium Chloride and Sodium Hydroxide. These salinity effects will impact on the outflow parameter in the water cycle with consequent reduction in evaporation which reduces precipitation, hence the formation of rain in the cloud would be inhibited and ultimately lead to climate change.

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