SEDL / STP / STP1188-EB / STP18086S

Improved Coatings Testing and Evaluation Using Electrochemical Impedance Spectroscopy

Kamarchik, P
Senior research associate, PPG Industries, Inc., Allison Park, PA

Pages: 12    Published: Jan 1993

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Abstract

Electrochemical impedance spectroscopy (EIS) of automotive and general industrial electrodeposited coatings and of container interior coatings for beverage and food end-uses is described. We have correlated the electrochemical impedance data with traditional test data from exposure testing ranging from continuous salt fog to cyclic scab corrosion, artificial sauerkraut exposure, canned pet food exposure, and food processing conditions. Changes in the impedance spectra after exposures of only a fraction of the usual exposure time were generally well-correlated with visual examination of the test panels after completion of the usual length of test. The impedance spectra permitted an early observation of film deterioration even though no visually observable changes had occurred.