Galvanic Series in Seawater as a Function of Temperature, Oxygen Content, and Chlorination

CORROSION ◽  
10.5006/2638 ◽  
2017 ◽  
Vol 74 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Dominique Thierry ◽  
Charles Leballeur ◽  
Nicolas Larché
Keyword(s):  
Oxygen Content ◽  
Open Circuit Potential ◽  
Driving Forces ◽  
Material Selection ◽  
Galvanic Corrosion ◽  
Open Circuit ◽  
Advanced Materials ◽  
Effect Of Temperature ◽  
Experimental Conditions ◽  
Steel Grades

The open-circuit potential is one of the main driving forces of galvanic corrosion when two dissimilar metals are in electrical continuity in an electrolyte. From the existing literature, the galvanic series which provides averaged potential of metallic materials in seawater is generally restricted to ambient/standard conditions or to a limited number of alloys. However, advanced materials have been developed in the last decade and the corrosion potential of any alloy immersed in seawater may be strongly affected by environmental factors. There is a lack of information on these purposes (e.g., effect of dissolved oxygen content, temperatures, chlorination at different levels, or recently developed alloys, etc.). In this work, the open-circuit potential of different stainless steel grades, as well as nickel-based and copper-based alloys, has been systematically measured in seawater under different experimental conditions. In particular, the effect of temperature (from 30°C to 70°C), oxygen content (from 10 ppb to saturation), and chlorination level (from 0 ppm to 0.5 ppm) have been studied. The work can also be used for material selection in terms of risk of bi-metallic corrosion when coupling two materials under these conditions.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

scholarly journals Gold Nanoparticles Synthesis Using Stainless Steel as Solid Reductant: A Critical Overview

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 622
Author(s):  
Margherita Izzi ◽  
Maria C. Sportelli ◽  
Luciana Tursellino ◽  
Gerardo Palazzo ◽  
Rosaria A. Picca ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Stainless Steel ◽  
Open Circuit Potential ◽  
Precursor Solution ◽  
Cost Effective ◽  
Open Circuit ◽  
Steel Composition ◽  
Experimental Conditions ◽  
Synthesis Parameters ◽  
Critical Overview

Gold nanoparticles (AuNPs) were produced using stainless steel as a solid reductant to assist the synthesis of metal NPs, using HAuCl4 as a precursor. This method is very easy, quick, and cost-effective, allowing the synthesis of highly stable NPs without additional capping agents. However, the reaction mechanism is still under debate. In order to contribute to the investigation of the synthesis of AuNPs using stainless steel, different experimental conditions were tested. Cl− concentration, pH of the precursor solution, as well as stainless steel composition were systematically changed. The syntheses were performed recording the open circuit potential to potentiometrically explore the electrochemical properties of the system, under operando conditions. Spectroscopic and morphological characterizations were carried out along with potentiometric monitoring, aiming at correlating the synthesis parameters with the AuNPs characteristics. As a result, an overview of the process features, and of its most reasonable mechanism were obtained.

scholarly journals Electrophysiology of K+ transport by midgut epithelium of lepidopteran insect larvae. IV. A multicompartment model accounts for tetramethylammonium entry into goblet cavities

1995 ◽  
Vol 198 (10) ◽  
pp. 2115-2125
Author(s):  
A Koch ◽  
D Moffett
Keyword(s):  
Goblet Cell ◽  
Driving Forces ◽  
Short Circuit ◽  
Basal Membrane ◽  
Open Circuit ◽  
Columnar Cell ◽  
Transport Activity ◽  
Cell Cytoplasm ◽  
Experimental Conditions ◽  
K Transport

A quantitative model was developed to explain the kinetics of tetramethylammonium (TMA+) movement into and out of the goblet cavities of posterior midgut cells of Manduca sexta based on the data of the accompanying paper, which indicated that TMA+ does not enter the goblet cavity directly from the lumen. The model has two cellular compartments between the lumen and goblet cavity; these have been tentatively identified as the columnar cell and goblet cell cytoplasm. Five transmembrane pathways are included: from lumen to columnar cell, from columnar cell to goblet cell, from goblet cell cytoplasm to goblet cell cavity, and across the basal membrane of each cell type. These pathways need not be channels; they could use endocytotic or exocytotic mechanisms or, in the case of the cell-to-cell passage, septate junctions. However, in all cases, transfer is proportional to the electrochemical gradient. The model was tested against the results obtained after exposure to TMA+ in short-circuited and open-circuited tissues as well as results from an open-circuited tissue that did not develop a large transepithelial potential. Although driving forces for TMA+ across the membrane barriers were quite different in the different experimental conditions, the transfer coefficients from lumen to columnar cell, from columnar to goblet cell and from both cells across the basal membrane were the same. The only transfer coefficient that changed between short-circuit and open-circuit conditions was that from goblet cell cytoplasm to goblet cavity. This value was high under short-circuit conditions (when K+ transport activity is high), but low under open-circuit conditions (when K+ transport activity is low). The model suggests a hypothesis in which TMA+ enters the goblet cavity by an indirect route across the cell membrane of columnar cells, and thence passes to the goblet cell cytoplasm through intercellular junctions. Results from experiments with cytochalasin E suggest that the actin-based cytoskeleton is involved in limiting cell­cell coupling. In this model, TMA+ passes from the goblet cell cytoplasm to the goblet cavity via the K+/nH+ antiport believed to mediate active transepithelial K+ transport. However, although actively transported K+ is believed to pass from goblet cavity to lumen, TMA+ cannot.

scholarly journals Galvanic Corrosion of Copper / Nickel-Chrome Alloy in an Agitated Sulfuric Acid Solution

2018 ◽  
Vol 21 (1) ◽  
pp. 133
Author(s):  
Samar S. Hussein ◽  
Basim O. Hasan ◽  
Naseer A. Al-Haboubi
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Flow Conditions ◽  
Galvanic Current

Galvanic corrosion of Nickel-Chrome alloy (Ni-Cr alloy) and Copper (Cu) coupled in 5% sulfuric acid solution was investigated. The effects of agitation velocity, temperature, and time on the galvanic corrosion current and the weight loss of both metals in both free corrosion and galvanic corrosion were investigated. The trends of open circuit potential (OCP) of each metal and galvanic potential (Eg) of the couple were also determined. The results showed that Cu was cathodic relative to Ni-Cr alloy in galvanic couple and the corrosion potential of the couple (Ni- Cr alloy /Cu) was between the values of the two single components because the OCP of copper shifted to positive with the increase in velocity. Under stagnant conditions initially the galvanic current was more negative then shifted to the positive with time. The corrosion of Ni-Cr alloy decreased with time because the passivation layer was formed on the surface. Under flow conditions, the galvanic current sharply shifted to the negative direction (increase galvanic current from Ni-Cr alloy (anode) to Cu (cathode) during the first few minutes.

scholarly journals Study on the Electrochemical Performance of Sacrificial Anode Interfered by DC Stray Current

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Qingmiao Ding ◽  
Tao Shen ◽  
Yanyu Cui ◽  
Juan Xue
Keyword(s):  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Chloride Ion ◽  
Open Circuit ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Sacrificial Anode ◽  
Stray Current ◽  
Anode Corrosion ◽  
The Impact

The influence of sacrificial anode electrochemical properties interfered by direct stray current (DC) of 0 V, 1 V, 3 V, and 5 V, with different chloride ion concentration and temperature, was studied by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and polarization curves. The specific performance was as follows: as the DC interference voltage increased from 0 V to 5 V, the degree of positive migration of the sacrificial anode open circuit potential increased. The effect of temperature in DC interference voltage environment on sacrificial anode corrosion was not great, but the low temperature of 10°C could slow down the sacrificial anode corrosion and maintain good work efficiency. With the increase of the ambient temperature, the degree of corrosion of the sacrificial anode was deepened. As the chloride ion concentration in DC interference voltage environment increased from 0% to 0.3%, the degree of positive migration of the sacrificial anode open circuit potential increased. The higher the chloride ion concentration was, the greater the impact on the performance of the sacrificial anode was.

ON THE FORMATION OF "Ag2O3" ON SILVER ELECTRODES

1965 ◽  
Vol 43 (5) ◽  
pp. 1199-1214 ◽  
Author(s):  
E. J. Casey ◽  
W. J. Moroz
Keyword(s):  
Current Density ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Anodic Current Density ◽  
Decomposition Rates ◽  
Anodic Current ◽  
Adsorbed Species ◽  
Experimental Conditions ◽  
Potential Decay ◽  
Silver Electrodes

"Ag2O3" was examined electrochemically in eutectic KOH−H2O at −40 °C by coulombic measurements of quantities formed, open circuit potential decays, variation of potential as a function of anodic current density, and temperature coefficients of decomposition rates. It can be formed directly from Ag2O on Ag at current density (c.d.) > 15 μA/cm2, with a maximum thickness during the first oxidation cycle (25 layers, assuming a surface roughness factor of one) occurring at 65 μA/cm2. Potential decay (−∂E/∂ log t ≡ b) curves have protracted linear regions where 0.045 < b < 0.078, sometimes higher. One-tenth of a layer of adsorbed species superimposed on the higher oxide exists on the surface during O2 evolution. Reduction curves show a minimum in the potential decay of the higher oxide preceding the formation of Ag2O. The "Ag2O3" decomposes in approximately 1 h at −40 °C to either AgO or Ag2O. The activation energy for its thermal decomposition is 12.0 ± 2.0 kcal/mole. Under most experimental conditions studied the results indicated that the material is not true Ag2O3 but it is probably better described as Ag2O[O] where [O] is trapped oxygen.The evidence does point to the probable existence of a thin layer, which may be true Ag2O3, on the surface in a steady state which is maintained at high anodic current density ( > 100 μA/cm2 at −40°).

scholarly journals Effect of Hydroxyapatite Coatings on Corrosion Behavior for Biotype 316L SS Used in Orthopaedic Applications

2010 ◽  
Vol 7 (3) ◽  
pp. 1237-1243
Author(s):  
Baghdad Science Journal
Keyword(s):  
Open Circuit Potential ◽  
Sintering Temperature ◽  
Electrochemical Corrosion ◽  
Substrate Material ◽  
Open Circuit ◽  
Applied Potential ◽  
Experimental Conditions ◽  
Ringer’S Solution ◽  
Optimum Parameters ◽  
Hydroxyapatite Coatings

Electrochemical corrosion of hydroxyapatite (HAP) coated performance depends on various parameters like applied potential, time, thickness and sintering temperature. Thus, the optimum parameters required for the development of stable HAP coatings was found by using electrophoretic deposition (EPD) technique. This study discusses the results obtained from open circuit potential-time measurements (OCP-time), potentiodynamic polarisation and immersion tests for all alloy samples done under varying experimental conditions, so that the optimum coating parameters can be established. The ageing studies of the coated samples were carried out by immersing them in Ringer’s solution for a period of 30 days indicates the importance of stable HAP coatings to prevent corrosion on the substrate material, so that enhancement to the biocompatibility will be increased.

Electrochemical Behavior of Alloy 825 at High-Temperature Pressurized Water–Chloride Solutions (30°C to 280°C)

CORROSION ◽  
10.5006/2817 ◽  
2018 ◽  
Vol 74 (11) ◽  
pp. 1245-1258 ◽  
Author(s):  
Lefu Zhang ◽  
Jiamei Wang ◽  
Farzin Arjmand
Keyword(s):  
High Temperature ◽  
Open Circuit Potential ◽  
Film Formation ◽  
Open Circuit ◽  
Experimental Conditions ◽  
Pressurized Water ◽  
Series Of Experiments ◽  
Do Concentration ◽  
Effects Of Temperature ◽  
Microscopic Surface

Variations in the transpassive potential (Et) and open circuit potential (OCP) of Alloy 825 were investigated at high-temperature pressurized water–Cl solutions. Using an experimental design strategy, the effects of temperature (T) (30°C to 280°C), Cl− concentration (10 ppb to 1,000 ppb), and dissolved oxygen (DO) concentration (0 ppb to 200 ppb) on the electrochemical responses (Et and OCP) of the alloy were analyzed by conducting only a short series of experiments. The optimum values of each factor was obtained from the designed matrix of the experiments and the constructed 3D response surface plots based on the most positive values of the Et and OCP. The optimum experimental conditions in which the most positive Et can be recorded was found as follows: T ≈ 30°C (significant), [Cl−] ≈ 10 ppb (significant), and [DO] ≈ 200 ppb (less significant). The most positive OCP values were recorded when the analyzed factors were as follows: T ≈ 120°C (significant), [DO] ≈ 200 ppb, and [Cl−] ≈ 10 ppb (less significant). Finally, the microscopic surface analysis of the alloy coupons revealed the great impact of temperature on the oxide film formation on Alloy 825.

A PROPOSAL FOR MODIFIED GALVANIC CORROSION MODEL: INVESTIGATING EFFECTS OF MICRO-ARC OXIDATION ON Al ALLOY

2019 ◽  
Vol 26 (02) ◽  
pp. 1850147
Author(s):  
YUANHANG YANG ◽  
YANHONG GU ◽  
JIAN LIANG ◽  
WEN YUE
Keyword(s):  
Open Circuit Potential ◽  
Galvanic Corrosion ◽  
Open Circuit ◽  
Al Alloy ◽  
Corrosion Mechanism ◽  
Corrosion Performance ◽  
Before And After ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Micro Structures

Corrosion is generally an undesirable phenomenon in most engineering applications. The effects of micro-arc oxidation (MAO) coating on Al alloy on the galvanic corrosion performance have been studied. The surface micro-structures were characterized using scanning electron microscope (SEM) and metallographic microscope before and after corrosion. Electrochemical studies on the corrosion behaviors have been reported by using open circuit potential (OCP) and potentiodynamic polarization (PDP) measurements in a slurry solution. All measurements were consistent with each other and showed that the MAO coating can significantly reduce the corrosion rate of Al alloy. A model for elucidating corrosion mechanism and corrosion process of the MAO coating on Al alloy is proposed.

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