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Communication Dans Un Congrès Année : 2022

Elementally resolved electrochemical impedance spectroscopy : dissolution kinetics for Ni, Cr-containing high-entropy alloys

Résumé

Elementally resolved dissolution kinetics of Ni, Cr alloys, and high-entropy alloys (HEAs) were investigated by a relatively novel coupling between the atomic emission spectroelectrochemistry (AESEC) technique and electrochemical impedance spectroscopy (EIS). The elemental dissolution rates obtained during AESEC-EIS measurements for pure metals will be used as an input for the prediction of dissolution kinetics of single-phase Ni-Cr(-Mo) alloys and NiCrFeMnCo HEAs. Fig. 1(a) shows a preliminary result of potentiostatic AESEC-EIS for a pure Ni in 2 M H2SO4 at the open circuit potential (Eoc). Ni dissolution rate (jNi) was in-phase with the applied sinusoidal potential, and resulting electrical current density (je) indicating a charge transfer mechanism of the Ni dissolution, in agreement with the Nyquist plot obtained during the measurement (Fig. 1(b)). An elementally resolved Lissajous plot is presented in Fig. 1(c) showing the jNi, je and jΔ. jΔ is obtained by a mass balance (= je - jNi) which may give a kinetic information of the cathodic reaction assuming no oxide formation, showing a reasonable pseudo-linearity. The same AESEC-EIS analysis will be carried out for the other alloying elements and for NiCrFeMn(Mo)Co HEAs which may give an elementally resolved mechanistic understanding of the complex alloy dissolution.

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Chimie
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Dates et versions

hal-03955697 , version 1 (25-01-2023)

Identifiants

  • HAL Id : hal-03955697 , version 1

Citer

Junsoo Han, Kevin Ogle. Elementally resolved electrochemical impedance spectroscopy : dissolution kinetics for Ni, Cr-containing high-entropy alloys. Eurocorr 2022 (European Corrosion Congress), Aug 2022, Berlin, Germany. ⟨hal-03955697⟩
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