Electrochemical evaluation and surface study of magnetite/PANI nanocomposite for carbon steel protection in 3.5% NaCl

Herein, a nanocomposite of polyaniline and magnetite (Fe3O4) nanoparticles (Fe3O4/PANI) was prepared through a two-step oxidative polymerization in different mass ratio as 1:1,1:2 and 2:1. Prepared Fe3O4/PANI nanocomposites were characterized by FT-IR, XRD, TEM, SEM and EDXA. A thin layer of the Fe3O4/PANI nanocomposites was used to coating carbon steel as corrosion protector film in NaCl 3.5%. Anti-corrosion performance of the Fe3O4/PANI nanocomposites was investigated through electrochemical techniques such as open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance (EIS). Observed results showed a dramatic shift in corrosion potential and a decrease in cathodic and anodic reactions rate in Tafel plots. Also, EIS data showed charge transfer resistance was increase after coating the carbon steel with Fe3O4/PANI nanocomposite. Affecting parameters like mass ratio, amount of nanocomposite, and film formation time, were optimized. Our electrochemical results showed that 100 mg/L of Fe3O4/PANI (1:1) nanocomposite in 60 mine can achieved to protection efficiency of 96.8% in 3.5% NaCl. Finally ability of proposed coating as an anticorrosive layer was further proofed by using surface methods i.e. SEM and EDXA. Observed results are presented and discussed. (C) 2016 Elsevier B.V. All rights reserved.