Change in Electrochemical Impedance Spectrum of Coated Steel Plate by High Temperature・High Humidity-Cold Cycle test

Abstract

Painted steel panel uses for automotive body. Therefore, assessments of painted steel corrosion protecting life are important. Automotive body is exposed to various atmospheric environments. Atmospheric environmental factors （temperature, humidity, adhering salt type, etc.） are influenced on corrosion protecting life of the painted steel. In order to evaluate the corrosion protection performance in a short time, we study evaluation of coating film degradation using EIS （Electrochemical Impedance Spectroscopy）. As a result, it was found that coating thickness, adhesion salt type and presence/absence of freezing process may contribute to degradation of corrosion protection performance.