Weathering exposure tests were performed on unscribed panels painted with organic coating systems consisting of various aerospace primers and pretreatments and a single topcoat (MIL-PRF-85285C). Electrochemical Impedance Spectroscopy (EIS) was used to measure the electrical properties of these exposed and unexposed coating systems at various time intervals. The relationship between the chromate leach rate for these different coating systems and the current coating system barrier properties was examined previously [1]. This current study evaluates UV/VIS/NIR, FTIR, and color measurements performed at various exposure intervals in order to monitor changes in chemical and electronic properties. Results indicate that changes in chemical properties track with measured impedance and color changes during weathering. The effects of weathering are strongest on untopcoated MIL-PRF-23377G epoxy primer and weakest on untopcoated TT-P-2760A polyurethane primer.

Subject
Primers, Absorption, Top coats, Substrates, Solids, Impedance, Epoxy primers, Polyurethanes, Fourier transform infrared spectrography, Waterborne epoxies, Color, Dry film thickness, Coating systems
Keywords:
Coatings, chromate, inhibitors, leachability, corrosion, corrosion protection, barrier properties, chemical properties
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).
2004
GOV
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