engleski

The application of AC impedance to study the performance of lacquered aluminium specimens in acetic acid solution

Auminium tubes with single and double coat solvent based and water based lacquers, based on epoxy-phenolic resins, were analysed. To determine the electrochemical parameters to correlate with the actual behaviour of a collapsible tube, impedance spectroscopy was used. The measurements were performed in 3% (v/v) acetic acid, at room temperature. After impedance measurements specimens surface were analysed by Scanning Electron Microscopy (SEM). As the coating degraded from penetration of electrolyte a rapid increase of coating capacitance, Cp, (from 10-10 to 10-8 F cm-2) and a rapid decrease in pore resistance, Rp, (from 108 to 106 Wcm2) occurred after 192 hours of immersion. Analysis of data from impedance measurements, such as Rp, Cp, and delaminated area (Adel) , enabled determination of coating performance exposed to an aggressive media.

acetic acid; AC impedance; aluminium; delamination; epoxy/phenolic resins; immersion test

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