Distribution of Potential and Current in Circular Corrosion Cells Having Unequal Polarization Parameters

McCafferty, E.

doi:10.1149/1.2133178

Cited by 64 publications

(57 citation statements)

References 27 publications

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“…For instance, Palani et al 21 considered ORR kinetics on carbon fiber reinforced polymer in contrast to this work on 316L stainless steel. This linear relationship between I cath and log WL was also present across similar film thicknesses in the work of McCafferty data 40 as well as the finite element modeling study by Morris and Smyrl; 8 however, the polarization parameters considered in those studies were extracted in the linear limit of kinetics near the open circuit potential. This analysis therefore yields another important insight; the nature of the kinetics itself does not affect the observation of a linear relationship between total cathodic current and logarithm of the WL thickness across a certain range of WL thicknesses lower than the boundary layer for natural convection (δ nc ).…”

Section: Discussionsupporting

confidence: 57%

Editors' Choice—Electrolyte Film Thickness Effects on the Cathodic Current Availability in a Galvanic Couple

Liu

Srinivasan

Kelly

2017

J. Electrochem. Soc.

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A combined modeling and experimental study was performed to understand the dependence of the cathodic current delivery capacity on the electrolyte film thickness and cathode size in a galvanic couple. The appropriate cathodic kinetics for the modeling were generated by use of a rotating disk electrode to simulate the electrolyte film thickness. These results provided boundary conditions for a finite element model which calculated the potential distribution along a metallic surface and the associated cathodic current supplied for electrolyte layers of varying thickness. The total cathodic current was then calculated through integration of the current density across the surface. Electrolyte layer domains were delineated by three limits which described, in order of decreasing film thickness, i) transition in exposure condition from full immersion to thick film, ii) the hydrodynamic boundary layer due to natural convection which defined the upper limit of the thin film regime, and iii) the relative dominance of ohmic resistance over mass transport in determining the total current output. This study also showed that for sufficiently thin films, this total current was independent of the size of the cathode and the nature of kinetics at the electrochemical interface, being solely driven by the ohmic resistance in solution. Dissimilar engineering alloys in close proximity and in electrical contact are frequently encountered in the architecture of high-value structural assets in the transportation, aerospace, and marine industries. In service, these structures are often exposed to atmospheric environments, such as sea spray, that result in the formation of a thin electrolyte layer on the surface sufficient to allow the dissimilar alloys to form galvanic couples. Under atmospheric conditions, the electrolyte can also form via deliquescence of salt as either a droplet or a thin film on the alloy surface, leading to the establishment of a corrosion cell. The extent of galvanic corrosion on the anode that results depends on a number of environmental, physicochemical, and geometric variables, which include relative humidity, temperature, electrolyte conductivity, electrolyte film thickness, in addition to the electrochemical kinetics on the alloy surface.1-7 Different exposure conditions can be modeled by varying the thickness of the electrolyte film (also termed the water layer, WL), which in turn affects solution resistance as well as cathodic kinetics, thus having a direct effect on the total cathodic current available to support corrosion of the galvanic system.The effects of the electrolyte film thickness on corrosion rate were recognized initially by Tomashov, 2 who qualitatively identified four regions of WL corresponding to different types of reaction control. As film thickness decreased, a transition from a plateau in corrosion rate when a constant diffusion layer was attained (conditions of full immersion) to cathodically controlled corrosion limited by diffusion of dissolved oxygen to the reaction surface (the corr...

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Section: Discussionsupporting

confidence: 57%

Editors' Choice—Electrolyte Film Thickness Effects on the Cathodic Current Availability in a Galvanic Couple

Liu

Srinivasan

Kelly

2017

J. Electrochem. Soc.

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“…22 -29 Other papers worth mention are those of Nanis and Kesselman, 136 Miller and Belavance, 137 McCaferty, 138 and Morris and Smyrl. 139 The Figure 16.…”

Section: Modelling and Simulationmentioning

confidence: 99%

Review—On the Application of the Scanning Vibrating Electrode Technique (SVET) to Corrosion Research

Bastos

Quevedo

Karavai

et al. 2017

J. Electrochem. Soc.

107

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This paper presents an introduction to the Scanning Vibrating Electrode Technique (SVET) and its application to corrosion research. Up to now it has been impossible to find a single work that could provide a simple and comprehensive introduction to this technique, giving a clear idea of what SVET is, how it works, the possibilities and limitations. This paper intends to fill this gap. It starts with a brief historical account, followed by the operating principle and selected examples of application to corrosion. Information about instrumentation and technical details are then highlighted, together with possible calculations and limitations. The paper ends with examples of the combination of SVET with other electrochemical techniques.

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“…Such studies are often carried out to investigate fundamental effects of electrolyte geometry [26,28,29], electrode kinetics [25], and unique part geometries [21]. Early modeling attempts have provided an analytical solution [26,30] for the galvanic current and potential distribution around a galvanic junction involving two dissimilar metals kept side by side and covered by a corroding solution. These theoretical predictions were also later validated with experimental measurement of the potential and current density across the junction.…”

Section: International Journal Of Corrosionmentioning

confidence: 99%

Numerical Simulation of Galvanic Corrosion between Carbon Steel and Low Alloy Steel in a Bolted Joint

Radouani

Ech-charqy

Essahli

2017

International Journal of Corrosion

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The galvanic corrosion of a bolt joint combining carbon steel end plate and low alloy steel bolt was investigated electrochemically in a 1 M HCl solution. The corrosion parameters of the joint components were used for numerical simulation using Comsol Multiphysics software to analyze the galvanic corrosion behavior at the contact zone between the head bolt and the end plate. In this research work we evaluate the variation of the corrosion rate in the steel end plate considered as the anode, in order to determine the lifetime of the bolted assembly used in steel structures. Three materials (20MnCr5, 42CrMo4, and 32CrMoV13) and three bolts (M12, M16, and M20) were tested in two thicknesses of electrolyte 1 M HCl ( = 1 mm, = 20 mm). It is found that the corrosion rate of the anode part (end plate) is higher for 32CrMoV13 materials and it increases if both diameter of the bolt and thickness of the electrolyte increase (Cr(M20) > Cr(M16) > Cr(M12) and Cr( = 20 mm) > Cr( = 1 mm)). This corrosion rate is higher in the contact area between the bolt head and the end plate, and it decreases if we move away from this contact area.

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Distribution of Potential and Current in Circular Corrosion Cells Having Unequal Polarization Parameters

Cited by 64 publications

References 27 publications

Editors' Choice—Electrolyte Film Thickness Effects on the Cathodic Current Availability in a Galvanic Couple

Editors' Choice—Electrolyte Film Thickness Effects on the Cathodic Current Availability in a Galvanic Couple

Review—On the Application of the Scanning Vibrating Electrode Technique (SVET) to Corrosion Research

Numerical Simulation of Galvanic Corrosion between Carbon Steel and Low Alloy Steel in a Bolted Joint

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