Electropolymerized coatings of polyaniline-CNT on stainless steel 310 and their corrosion protection performance in chloride environment

Stainless steel 310 (SS 310) is widely used in many fields due to its good corrosion resistance as well as its mechanical properties. The resistance to corrosion in aqueous media is attributed to the presence of a thin protective chromium-enriched oxide film. Several strategies have been used togenerate more protective interfaces on stainless steels, including the use of conducting polymers [1, 2]. In this work, homogeneous, uniform and adherent polyaniline-carbon nanotube (PANICNT)nanocomposite coatings were electrosynthesized on SS 310 by using the current densityfixed in the under galvanostatic conditions method. The synthesized coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), SEM and UV-Vis spectroscopy. Opticalabsorption spectroscopy shows the synthesis polymers of the emeraldine state that is suitable for a corrosion purposes. The corrosion performances of coatings were investigated in 5000 ppm NaCl solution used by the potentiodynamic polarization technique and electrochemicalimpedance spectroscopy (EIS). The current corrosion decreases significantly from 140.39 μA cm−2 for blank electrode SS 310 to0.27 μAcm−2 for PANI-CNT nanocomposite coatings, under optimal conditions. Also, the potential corrosion increases from -386.42 mV versus Ag/AgCl for blank electrode SS 310 to-40.19 mV versus Ag/AgCl for PANI-CNT nanocomposite coated stainless steel electrodes underoptimal conditions. The results of this study clearly ascertain that the PANI-CNT has outstanding potential to protect the SS 310 against corrosion in a chloride environment.

Keywords:

Nanocomposite , Electrochemical synthesis , Corrosion , Stainless steel 310