Corrosion studies on electrochemically deposited polyaniline and polyaniline/epoxy coatings on mild steel in acid sulfate solution

Abstract

The corrosion behavior of mild steel, mild steel covered by electrochemically deposited polyaniline (PANI) film, epoxy coating and PANI/epoxy coating system in 0.1 M sulfuric acid solution, were investigated by electrochemical impedance spectroscopy (EIS). Electrochemical deposition of PANI film was performed from aqueous solution of 0.5 M sodium benzoate and 0.1 M aniline at constant current density of 1.5 mA cm-2. Epoxy coatings on mild steel and mild steel modified by PANI film were deposed at constant voltage. It was shown that thin PANI film had provided good corrosion protection of mild steel in 0.1 M sulfuric acid solution, and could be used for modification of mild steel prior to epoxy coating deposition. The increased corrosion protection of mild steel by PANI / epoxy coating system in the same solution was obtained.

Koroziono ponašanje mekog čelika, mekog čelika sa elektrohemijski taloženim filmom polianilina (PANI), epoksi prevlake na mekom čeliku i PANI/epoksi sistema na mekom čeliku, je ispitivano primenom elektrohemijske impedansne spektroskopije (EIS). Elektrohemijsko taloženja filma PANI na mekom čeliku je ostvareno u vodenom rastvoru 0.5 M Na-benzoata i 0.1 M anilina, pod galvanostatskim uslovima (1.5 mA cm-2). Eposkidne prevlake na mekom čeliku i mekom čeliku modifikovanom sa filmom PANI, su taložene u uslovima konstantnog napona. Pokazano je da PANI film omogućava dobru zaštitu mekom čeliku od korozije u 0.1 M rastvoru sumporne kiseline, pa se može koristiti kao modifikacija mekog čelika pre taloženja epoksidnih prevlaka. Uočena je povećana koroziona zaštita mekog čelika sa prevlakom PANI/epoksi, u odnosu na meki čelik sa epoksi prevlakom.