Steel Corrosion Characterization Using Pulsed Eddy Current Systems

A pulsed eddy current (PEC) system has been used to characterize atmospheric corrosion on steel samples. International Paint has supplied coated and uncoated mild steel (S275) samples with marine atmospheric corrosion (exposure time between 1 and 10 months). The PEC response due to corrosion is a complex mix of many factors, including conductivity, permeability and material thickness variation, which are all taken into account through experimental studies and the extraction of signal features. Considering the conductivity and permeability variation in the corrosion layer or the actual rust region, two time-domain features, each representing the conductivity and permeability, are extracted and used to characterize corrosion. The relationship between PEC features and exposure time has been derived, which can be useful for corrosion rate measurement and early-stage corrosion evaluation and prediction. In conclusion, PEC testing has the potential for corrosion characterization and monitoring in areas such as the marine industry.