From rectangular to circular geometries: enhancing real-time corrosion sensing through geometrical optimization of IDE based electrochemical sensor

Real-time corrosion monitoring is critical for ensuring the integrity of structural materials and preventing failures in various industries. Electrochemical sensors based on rectangular comb-shaped interdigitated electrodes (IDEs) are widely employed for this purpose due to their simplicity, low cost, and effectiveness. This study explores the geometrical optimization of a comb-shaped IDE to improve sensor performance while maintaining compactness. Key design parameters, such as gap length, electrode width, thickness, and tooth dimensions, are varied to model the electric field distribution, which in turn will affect the corrosion rates. To address edge effects, a modified IDE with rounded corners is examined, followed by the design and simulation of a circular-shaped IDE with identical area and dimensions. The simulation reveals that the circular IDE produces a more uniform electric field, enhancing corrosion detection reliability. Experimental validation, using fabricated rectangular and circular IDEs on AA2024 alloy, coupled with Linear Polarization Resistance (LPR) and Tafel tests, also demonstrates a strong correlation between electric field uniformity and corrosion rates. These findings underscore the potential of optimizing the geometry of IDEs and conclude that a circular-shaped IDE exhibits superior performance relative to a rectangular IDE, resulting in enhanced accuracy for real-time corrosion monitoring.