Uncovering accurate values of the polarization resistance in molten fluorides using electrochemical impedance spectroscopy - UFR de Chimie de Sorbonne-Université
Article Dans Une Revue Journal of Electroanalytical Chemistry Année : 2024

Uncovering accurate values of the polarization resistance in molten fluorides using electrochemical impedance spectroscopy

Ho Lun Chan
  • Fonction : Auteur
  • PersonId : 1421554
John R Scully
  • Fonction : Auteur
  • PersonId : 1226990

Résumé

High-temperature operation and the presence of oxidizing impurities in molten chloride and fluoride salts pose significant corrosion risks to structural alloys in molten salt nuclear reactors. Electrochemical impedance spectroscopy (EIS) offers an operando, real-time method to study the instantaneous corrosion behavior of these materials non-destructively. However, signal noises may originate from sources extraneous to the electrochemical systems that limit the ability to perform quality impedance measurements in low-frequency regime where polarization resistance (Rp) dominates. Using the exposure of pure Cr in molten LiF-NaF-KF containing 1 wt% EuF3 at 600 °C as a model corrosion system, the extent of Non-Uniform Current and Potential (NUCP) distribution during an AC perturbation associate with the disk electrodes is evaluated in terms of two dimensionless correction factors $k_f^{Rct}$ ( = $R_{ct}$/$R_{eff}$) and $k_f^{Cdl}$ ( = $C_{dl}$/$C_{eff}$). Results show that a small area Cr disk electrode increases the transition frequency that marks the dominance of Rp to a conventional terminational frequency above 10−2 Hz, enabling a reliable charge-transfer resistance (Rct) value to be determined via circle fitting an electrical equivalent circuit model (ECM) model. Experimental results were supported by EIS simulations considering commonly used ECM models that factor in the NUCP effect of the bulk rectangular and disk geometries.

Domaines

Autre
Fichier sous embargo
Fichier sous embargo
0 4 25
Année Mois Jours
Avant la publication
lundi 3 mars 2025
Fichier sous embargo
lundi 3 mars 2025
Connectez-vous pour demander l'accès au fichier

Dates et versions

hal-04719425 , version 1 (03-10-2024)

Identifiants

Citer

Ho Lun Chan, Harjot Singh, Valentin Romanovski, Elena Romanovskaia, Junsoo Han, et al.. Uncovering accurate values of the polarization resistance in molten fluorides using electrochemical impedance spectroscopy. Journal of Electroanalytical Chemistry, In press, pp.118619. ⟨10.1016/j.jelechem.2024.118619⟩. ⟨hal-04719425⟩
0 Consultations
0 Téléchargements

Altmetric

Partager

More