Oil-Immersed Scanning Micropipette Contact Method Enabling Long-term Corrosion Mapping

Area of Science:

• Materials Science
• Electrochemistry
• Corrosion Science

Background:

• The scanning micropipette contact method is valuable for localized electrochemical analysis.
• Investigating localized corrosion on aluminum alloys presents challenges due to solution evaporation and humidity.
• Enhanced droplet stability is crucial for prolonged and accurate electrochemical mapping.

Purpose of the Study:

• To develop and validate an oil-immersed scanning micropipette contact method.
• To improve droplet stability for electrochemical measurements in evaporative solutions.
• To investigate localized corrosion on AA7075-T73 aluminum alloy surfaces.

Main Methods:

• Development of an oil-immersed scanning micropipette contact technique.
• Utilizing potentiodynamic polarization curves for electrochemical analysis.
• Systematic mapping of corrosion potentials and currents on an AA7075-T73 aluminum alloy surface in 3.5 wt % NaCl solution.

Main Results:

• The oil-immersed method significantly enhances droplet stability, enabling prolonged measurements.
• Localized corrosion mapping correlated well with surface composition and microscale galvanic interactions.
• Successful investigation of AA7075-T73 aluminum alloy corrosion in a challenging saline electrolyte.

Conclusions:

• The oil-immersed scanning micropipette contact method is a viable technique for microscale corrosion studies.
• This method overcomes limitations of conventional techniques regarding solution evaporation.
• It opens new possibilities for mechanistic corrosion investigations using volatile aqueous solutions.