Exploring the combined effect of DC polarization and high temperature exposure on the barrier properties of organic coatings

Organic coatings are evaluated by various electrochemical, accelerated and natural exposure test methods. Among the expedited electrochemical approaches, measurements such as electrochemical impedance spectroscopy (EIS) at high temperature (HT EIS), and AC-DC-AC have been used previously. In this work, we attempted to combine these two approaches to further expedite the test and perform high temperature AC-DC-AC (HT AC-DC-AC) on organic coatings and compare the results with individual AC-DC-AC, and HT EIS measurements. A commercially available standard epoxy primer, and a formulated blank epoxy was used for the experiment. It was observed that HT AC-DC-AC can expedite the barrier changes in coating more rapidly compared to the use of only AC-DC-AC or HT EIS.