Fusion Bonded Epoxy (FBE) coating is one of the most accepted and effective coating systems that used for corrosion protection of steel structure. With the increased demand in high temperature applications and advancements in FBE coating technology, more and more FBE coatings with high glass transition temperatures (Tg≥120°C) are developed. The objective of this study is to investigate blistering formation of high Tg FBE coatings in an attempt to understand the blistering mechanism. In this work, five (5) candidate FBE coating systems with Tg temperatures in a range of 125-155°C were evaluated using hot water immersion, Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Differential Scanning Calorimetry (DSC), Ion Chromatography (IC) and Electrochemical Impedance Spectroscopy (EIS) techniques. The results of the study can assist in understanding the failure mechanism and life expectancy of high Tg temperature FBE coatings in hot immersion environments, and can be used to direct the development of proper new high Tg FBE coating products, to identify weak link in coating application, and the selection of suitable coatings for their specific applications.
Key words: FBE coatings, high Tg temperature, blisters, blistering mechanism, hot water immersion, FTIR, DSC, IC, EIS