Quantitative Interpretation of Potentiodynamic Polarization Curves Obtained at High Scan Rates in Scanning...

Area of Science:

• Electrochemistry
• Materials Science
• Corrosion Science

Background:

• Scanning electrochemical cell microscopy (SECCM) is a key technique for localized metal corrosion analysis.
• Potentiodynamic polarization measurements in SECCM are often conducted at high potential scan rates.
• Traditional Tafel extrapolation methods are inaccurate at high scan rates due to charging currents and mass transport limitations.

Purpose of the Study:

• To develop a quantitative method for analyzing local corrosion kinetics using SECCM.
• To address the inaccuracies of Tafel extrapolation at high potential scan rates.
• To apply the high field model for simulating potentiodynamic polarization curves.

Main Methods:

• Utilized the high field model to simulate potentiodynamic polarization curves.
• Performed simulations for pure aluminum at scan rates of 25, 50, 100, and 200 mV/s.
• Investigated corrosion behavior in neutral and acidic phosphate solutions.

Main Results:

• The high field model successfully simulated potentiodynamic polarization curves.
• Quantitative analysis of local corrosion kinetics was achieved by fitting the simulated curves.
• The method provides a more accurate assessment of corrosion kinetics compared to Tafel extrapolation at high scan rates.

Conclusions:

• The high field model offers a robust approach for quantitative corrosion kinetics analysis in SECCM.
• This method overcomes limitations associated with high-scan-rate potentiodynamic polarization measurements.
• Accurate localized corrosion kinetics can be determined for materials like aluminum in various solutions.