Simulation of the role of vibration on Scanning Vibrating Electrode Technique measurements close to a disc in plane

Долгих, О. В.; Demeter, A.S.; Lamaka, Sviatlana V.; Taryba, Maryna; Bastos, A.C.; Quevedo, Marcela C.; Deconinck, Johan

doi:10.1016/j.electacta.2016.01.188

Cited by 33 publications

(27 citation statements)

References 20 publications

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“…The same conclusion was reached in a recent study for the SVET system used in this work. 116 This effect, however, is strongly dependent on the probe size, probe-surface distance and amplitude of vibration.…”

Section: Operational Detailsmentioning

confidence: 99%

“…The suppression of concentration gradients around the probe minimizes the diffusion current and, as a result, the migration current becomes close to the total current, even inside the diffusion layer. 116 This explains why SVET measures the total current density irrespectively of the distance to the electrode, while standard calculations predict a strong decrease of migration current inside the diffusion layer with a concomitant increase in diffusion current. Fig.…”

Section: Operational Detailsmentioning

confidence: 99%

“…117 It has been suggested that this effect remains during SVET operation (when it vibrates) and could be responsible for the mismatch in positive and negative currents in SVET maps. 118 However, as discussed by Dolgikh et al, 116 the vibration cancels the concentration gradients around the vibrating electrode and the differences in Nernst equilibrium at the two ends of vibration should be negligible. This in fact was already acknowledged by Jaffe and Nuccitelli 2 and by Ferrier and Lucas.…”

Section: Operational Detailsmentioning

confidence: 99%

“…Recent calculations took into account the local mixing induced by the vibration and radically different results were obtained. 116 Fig . 13b shows the total current density and the migration current from standard calculations together with the migration component calculated considering the local mixing when the probe is placed at 250 μm, 100 μm or 30 μm from the surface.…”

Section: Operational Detailsmentioning

confidence: 99%

“…Models vary from the more simple electrostatic or potential model, based on the Laplace equation and considering only potential gradients in a medium of uniform conductivity, 93,95,[122][123][124][125][126][127][128] to more rigorous treatments contemplating the electrochemical gradients resulting from transport and reaction of chemical species in the solution using the Nernst-Planck equation. 94,96,116,119 With this model, not only current and potential are modelled but also the local chemistry, including the distribution of pH, O 2 and corrosion products. An illustrative example of the application of numerical modeling of SVET results can be given for the cut-edge corrosion presented in Fig.…”

Section: Modelling and Simulationmentioning

confidence: 99%

See 4 more Smart Citations

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

Bastos

Quevedo

Karavai

et al. 2017

J. Electrochem. Soc.

108

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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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Section: Operational Detailsmentioning

confidence: 99%

Section: Operational Detailsmentioning

confidence: 99%

Section: Operational Detailsmentioning

confidence: 99%

Section: Operational Detailsmentioning

confidence: 99%

Section: Modelling and Simulationmentioning

confidence: 99%

See 3 more Smart Citations

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

Bastos

Quevedo

Karavai

et al. 2017

J. Electrochem. Soc.

108

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Local pH and Its Evolution Near Mg Alloy Surfaces Exposed to Simulated Body Fluids

Lamaka

González

Mei

et al. 2018

Adv Materials Inter

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Many reports are available on degradation rates and corrosion product characterization of magnesium alloys for implant application. Typically, the data are obtained ex situ, as post factum analysis of occurred degradation processes or in bulk electrolyte that does not fully reflect concentration gradients at the interface and in the diffusion layer. Meanwhile, these local conditions are essential for tissue‐implant compatibility. Only a limited number of studies employ the techniques that visualize ongoing degradation and are localized enough to observe the changes in the electrolyte layer directly adjacent to corroding magnesium. Here, local pH in Hank's solution is studied in operando, with potentiometric micro‐probes (d = 2 µm) located 10–50 µm above the surface of four Mg alloys potentially relevant for implant applications. A significant difference in local pH is observed for Mg in simple Hank's solution (near surface pH 9.9–10.5) or Hank's solution modified with 2.5 × 10−3 m Ca2+ (pH 7.8–8.5). The corresponding pH values are established during the first seconds of immersion. These findings indicate different degradation kinetics in electrolytes with or without Ca2+. The degradation rate of Mg alloys decreases by almost two times in Ca2+ containing Hank's solution. Calcium‐phosphate/carbonate protective layer stabilizes the surface pH below 8.5 controlling Mg degradation.

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Evaporation of Electrolyte during SVET Measurements: The Scale of the Problem and the Solutions

et al. 2019

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The objective of this work is to investigate the scale of the effect of spontaneous solution evaporation during SVET (Scanning Vibrating Electrode Technique) measurements and demonstrate how it biases the final results. When SVET maps are continuously acquired for more than several hours, the measured currents are smaller than expected. This is attributed to solvent (typically water) evaporation which leads to an increase in solution conductivity over time. If this is not considered when converting the measured potential differences into the local current densities, the SVET results display currents smaller than the true ones. Here, this effect is studied with a platinum disk electrode as source of a constant current and a model corroding system consisting of the AA2024/CFRP galvanic couple. Corrective actions are proposed to mitigate the problem, either in the experimental set‐up or as numerical correction.

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Simulation of the role of vibration on Scanning Vibrating Electrode Technique measurements close to a disc in plane

Cited by 33 publications

References 20 publications

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

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

Local pH and Its Evolution Near Mg Alloy Surfaces Exposed to Simulated Body Fluids

Evaporation of Electrolyte during SVET Measurements: The Scale of the Problem and the Solutions

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