Microscale chemical imaging to characterize and quantify corrosion processes at the metal-electrolyte interface

Area of Science:

• Materials Science
• Electrochemistry
• Analytical Chemistry

Background:

• Corrosion processes at metal-electrolyte interfaces are crucial in many industrial applications.
• Understanding these processes under stagnant, confined conditions is challenging.
• Existing methods lack the resolution to characterize interfacial precipitate formation in-situ.

Purpose of the Study:

• To introduce a novel experimental setup for in-situ chemical imaging of corrosion.
• To investigate the precipitation and transformation of corrosion products at the metal-electrolyte interface.
• To quantify corrosion rates and understand the role of diffusion and oxygen.

Main Methods:

• Utilized a glass capillary setup for confinement.
• Employed optical microscopy for monitoring precipitate formation.
• Applied synchrotron-based X-ray fluorescence, X-ray diffraction, and X-ray absorption spectroscopy for chemical and structural characterization.
• Performed X-ray transmission measurements for precipitate quantification.

Main Results:

• Demonstrated the capability to monitor and chemically characterize corrosion products in-situ.
• Identified ferrihydrite precipitation and its transformation to goethite during iron corrosion.
• Highlighted the critical roles of O2 and iron diffusion in governing these processes.
• Obtained in-situ corrosion rates through precipitate quantification.

Conclusions:

• The developed capillary setup enables detailed investigation of corrosion at the metal-electrolyte interface with micrometer-scale resolution.
• This method provides fundamental insights into corrosion mechanisms and reactive transport.
• The setup is adaptable for studying various metals and environmental conditions, with significant potential for future in-situ corrosion research.