Value-Added Impedance Analysis for Predicting Barrier Coating Durability

Electrochemical impedance spectroscopy (EIS) has long been used to assess barrier coatings, yet its potential is still not fully exploited. The low-frequency impedance (log Z at 0.1 Hz), often serving as a momentary indicator of coating performance, is of limited predictive value. This study introduces an extended approach by employing the accelerated water uptake parameter and integrating dynamic response analysis with conventional log Z metrics. Data from two coatings, representing extremes of barrier performance, demonstrate how impedance changes can predict degradation before visible defects arise, thereby enabling improved durability assessment and predictive maintenance of barrier coatings.