engleski

Gel-Electrolyte EIS setup used for probing of IR Dried/Cured industrial coatings

Probing of IR dried/cured solvent based industrial coatings has been done by employing a two-electrode, gel-electrolyte electrochemical impedance spectroscopy setup that has enabled measurement of the coating electrical characteristics without the influence of the liquid electrolyte. In the present study, along with the coating impedance at 0.1 Hz, we suggest the use of the first derivative of the phase angle as a sensitive tool to detect the influence of the corrosion related low frequency RC circle appearance on the coating performance in the early stages of exposure. The conclusions of the EIS analysis are that the IR curing improves barrier properties of common industrial coatings and decreases the coating capacitance and dielectric constant, with respect to the laboratory ambient dried/cured referent systems. FTIR and DSC show no indications of permanent coating degradation, while the pull-off strength shows a slight, ≤ 10% decay of coating adhesion/cohesion characteristics. The water uptake calculated from the EIS data compared to the FTIR and DSC results, indicates various modes of water adsorption into the coating. It has been demonstrated that EIS may be used for obtaining quick information about the early-stage, non- visible coating degradation in the case of IR drying/curing as a time saving production process alteration that may bring significant benefit to the manufacturer of coated metallic products.

EIS ; IR curing ; coating ; corrosion ; resistance

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