Time\u2010resolved in situ electrochemical atomic force microscopy imaging of the corrosion dynamics of AA2024\u2010T3 using a new design of cell

Ahmed Kreta,Igor Muševič,Miran Gaberšček

doi:10.1557/s43578-020-00077-2

Abstract

An electrochemical cell was designed to enable in situ atomic force microscopy (AFM) measurements. The finite‐element method was implemented using COMSOL Multiphysics to simulate the electrical field within the cell and to find the current and potential distribution. A comparative three‐dimensional simulation study was made to compare two different designs and to elucidate the importance of the geometry on the electrical field distribution. The design was optimized to reduce the uncertainty in the measurement of the electrochemical impedance. Then, an in situ, simultaneous electrochemical and time‐resolved AFM experiments were conducted to study the surface evolution of the aluminum alloy AA2024‐T3 exposed to 0.5 M NaCl. The temporal change of the surface topography was recorded during the application of chrono‐amperometric pulses using a newly designed electrochemical cell. Electrochemical impedance spectroscopy was conducted on the sample to confirm the recorded topographical change. The newly developed cell made it possible to monitor the surface change and the growth of the oxyhydroxide layer on the AA2024‐T3 with the simultaneous application of electrochemical methods.

Highlights

To enhance the mechanical properties of aluminum, it is usually alloyed with elements like copper (Cu), gold (Au) [1], magnesium (Mg), manganese (Mn), silicon (Si), chromium (Cr), iron (Fe), and zinc (Zn)
A comparative study showed the effect of electrode geometry and arrangement on the uniformity of current and voltage distributions in an electrochemical cell intended for in situ atomic force microscope (AFM) measurements. 3D finite-element method (FEM) simulations showed that the newly proposed cell design had a much more uniform current and voltage distribution in the electrolyte than an earlier design
The selection of the reference electrode in the new design can reduce the uncertainty of displacing it by a factor of 60 times less than our previous design

Summary

Introduction

To enhance the mechanical properties of aluminum, it is usually alloyed with elements like copper (Cu), gold (Au) [1], magnesium (Mg), manganese (Mn), silicon (Si), chromium (Cr), iron (Fe), and zinc (Zn). It should allow the use of a standard reference electrode, which helps in reducing the uncertainty in the measured potential in the electrochemical cell.

Results

Conclusion