Investigation of the influence of scan rate on the electrochemical deposition of polyaniline (PANI) on mild steel via cyclic voltammetry and its corrosion protection in 0.4 M Na2SO4 solution

This study reports the deposition of polyaniline (PANI) coatings on mild steel (MS) by cyclic voltammetry. The PANI coating was prepared from 0.3 M aniline in 0.2 M sodium potassium tartrate (Na-K tartrate). The effect of scan rate was investigated on the development of a homogenous and adherent PANI coating on MS. The surface morphology and roughness of the PANI coating were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The coatings thus obtained were very smooth, uniform, compact, pore-free, fine-grained in nature, and highly adherent to the MS. The corrosion protection of the PANI coatings was studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in 0.4 M sodium sulphate (Na 2 SO 4 ). The inhibition efficiency (IE) of the PANI coating obtained was approximately 91 %, and the PANI film showed a mixed type of inhibitor.