Influence of the electrolyte film thickness and NaCl concentration on the oxygen reduction current on platinum

Долгих, О. В.; Bastos, A.C.; Oliveira, A. R.; Dan, Calin; Deconinck, Johan

doi:10.1016/j.corsci.2015.10.025

Cited by 30 publications

(22 citation statements)

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“…In the case of oxygen reduction, that information is not available. Nonetheless, the literature 2,14,16,22,29,39 cites values of δ nc from 250 μm to 1 mm. Tomashov 2 estimated that thin film conditions could be considered to apply for WL < 1 mm.…”

Section: Discussionmentioning

confidence: 99%

“…Attempts to develop a rigorous study of this dependence have since been made by a number of researchers. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Nishikata et al, 14,15 in their experimental studies on the oxygen reduction reaction (ORR) cathodic kinetics of both iron and platinum under an electrolyte thin film, observed a one-dimensional, Fickian relationship between the limiting current density for ORR and the film * Electrochemical Society Student Member.* * Electrochemical Society Fellow. z E-mail: rgk6y@virginia.edu thickness over the range 20 μm to 1 mm.…”

mentioning

confidence: 99%

“…Recently there have been modeling studies [18][19][20][21][22][23][24] that have focused on corrosion under an electrolyte thin film instead of full immersion. Dolgikh et al 24 performed a combined experimental and modeling study which incorporated the idea that convective flux could be expressed in terms of an analogous diffusion term.…”

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confidence: 99%

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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: Discussionmentioning

confidence: 99%

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confidence: 99%

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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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“…114 The importance of determining the relationship between ORR diffusional cathodic kinetics and electrolyte layer thickness is that for quite a few galvanic corrosion systems, the galvanic coupling potential and current density is located in the diffusional region of cathodic kinetics pertinent to ORR of the cathode. Dolgikh, et al, 115 incorporated the method from Amatore, et al, 116 in which a diffusion-like term was used to replace the convection term in the N-P Equation in order to account for the natural convection, and they conducted both electrochemical measurements and FEM modeling to quantify the dependence of oxygen reduction current on the electrolyte layer thickness and NaCl concentration based on platinum. It was found that oxygen reduction current at steady-state for all NaCl concentrations were almost constant until electrolyte layer thicknesses (WL) of ∼500 μm, and then increased with decreased WL from both experiment and simulation, which implied the critical boundary layer thickness was about 500 μm.…”

Section: Atmospheric Localized Corrosionmentioning

confidence: 99%

A Review of the Application of Finite Element Method (FEM) to Localized Corrosion Modeling

Kelly

2019

CORROSION

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The modeling of localized corrosion has usually focused on calculating the spatial and/or temporal distributions of chemical species, potential, and current. These are affected by the reactions considered, the geometry, and the modes of mass transport of importance. Finite element method (FEM) is a numerical technique to obtain approximate solutions to the differential equations based on different types of discretization in which the domain of interest is divided into different types of elements. The introduction of the FEM opened a variety of opportunities for increasing the complexity, and therefore the fidelity, of the localized corrosion conditions considered. This article first briefly introduces the FEM technique before describing the choices the modeler has with regards to the governing equations for the system. The history of the application of FEM to localized corrosion is given, highlighting the different aspects of localized corrosion that have been successfully modeled. Finally, some of the current challenges in FEM modeling of localized corrosion are outlined.

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“…The atmospheric corrosion coupled with the fatigue effect caused by the vibration leads to the fracture of aircraft structure. Great efforts are being made to model atmospheric corrosion mathematically, because these models can be helpful in various fields of technology . In contrast with other paper, this work proposes a simulation prediction system, test pieces → flat test pieces → structural parts, for the atmospheric corrosion of aircraft which provides new ideas for the application of corrosion simulation on aircraft corrosion prediction.…”

Section: Introductionmentioning

confidence: 99%

A method of atmospheric corrosion prediction for aircraft structure

Chen

Huang

Zhang

et al. 2018

Materials & Corrosion

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A simulation prediction system, test pieces → flat test pieces → structural parts, for the atmospheric corrosion of aircraft is proposed to provide guidance for aircraft anti‐corrosion material selection and outfield maintenance. Based on the shell current distribution, a COMSOL corrosion simulation prediction model was constructed and applied to three types of test parts. The correctness of simulation principle is verified by comparing the galvanic current of simulation and test on each electrode surface of multi‐electrode system. Comparing the simulated potential distribution at 100 µm electrolyte layer with the corrosion morphology after 12 wet–dry corrosion periods, it is found that simulation and test are in good agreement. It is also proved that the 100 µm static liquid film can reflect the corrosion of this kind of wet–dry cycle. Comparing the corrosion depths of different periods at three different points and the simulated corrosion depth with time, it is found that the corrosion depth of the first four periods was larger than the simulated depth, which was less than the simulated value after four periods. The model was applied to the local structural parts of aircraft. Then, corrosion position and corrosion area were predicted. The results were compared with the accelerated test results to verify the accuracy of the model's prediction of structural parts. At the same time, the corrosion depth of the structural parts was also predicted.

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Influence of the electrolyte film thickness and NaCl concentration on the oxygen reduction current on platinum

Cited by 30 publications

References 32 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

A Review of the Application of Finite Element Method (FEM) to Localized Corrosion Modeling

A method of atmospheric corrosion prediction for aircraft structure

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