Abstract:

Zinc–nickel alloy coating (ZnNi) was successfully deposited on carbon steel (CS) applying current density of 47 mAcm-2 with galvanostatic technique. The ZnNi alloy coating image showed that CS metal surface was plated with a blue-grey homogeneous layer. Polyaniline film (PANI) film was synthesized with cyclic voltammetry technique from 0.10 M aniline containing 0.20 M sodium oxalate solution on ZnNi coated carbon steel (CS/ZnNi) electrode surface. And then the synthesis of top PPy film was achieved in pyrrole monomer containing acetonitrile + tetrabutyl ammonium perchlorate medium successfully. After the top PPy synthesis, it was observed that both the PANi homopolymer film and the ZnNi coating continued to exist on the CS surface. The corrosion behaviors of uncoated and coated electrodes were investigated in 3.5% NaCl solution. For this aim, the anodic polarization plots and electrochemical impedance spectroscopy technique were used. The results showed that the top PPy homopolymer film provided an effective barrier property on CS/ZnNi/PANi electrode and a remarkable anodic protection to substrate for longer exposure time.

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