Two distinctly prepared epoxy coating systems characterized primarily by Electrochemical Impedance Spectroscopy (EIS) after having been exposed for 2 weeks to ASTM D 1141 electrolyte (substitute ocean water), were subjected to various laboratory environment drying periods. The coating types were a conventional solvent based MIL-DTL-24441, Type IV system and a “100% solids” type system reported to satisfy MIL-P-23236. The EIS data show both fully water saturated coating systems lose approximately 50% of the absorbed water within 48 hours of drying, which significantly affects the EIS parameters. Approximately 10 days’ re-exposure to the test electrolyte was required to reestablish the near-saturated water level and EIS characteristics. Electrochemical differences between the two types of epoxy coating systems are presented and discussed.

Subject
Electrochemical impedance spectroscopy, Water, Coatings, Electrochemical cells, Solids, Impedance, Capacitance, Coating thickness, Epoxy coatings, Drying, Drying time, Electrolytes, Coating systems
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2005
GOV
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