Electrodeposition of polyaniline-montmorrilonite nanocomposite coatings on 316L stainless steel for corrosion prevention

The synthesis of polyaniline- montmorrilonite (MMT) nanocomposite coatings on 316L stainless steel (316L SS) surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV-visible absorption spectrometry and Scanning Electron Microscopy (SEM). The anticorrosion performances of polyaniline-MMT nanocomposite coatings were investigated in 0.5 M HCl medium by the potentiodynamic polarization technique and Electrochemical Impedance Spectroscopy (EIS). The corrosion rate of polyaniline-MMT nanocomposite coated 316L SS was found ∼540 times lower than bare 316L SS and potential corrosion increased from −0.386 V versus Ag/AgCl for uncoated 316L SS to −0.040 V versus Ag/AgCl for polyaniline-MMT nanocomposite coated 316L SS electrodes. Electrochemical measurements indicate that polyaniline-MMT nanocomposite coated have good inhibiting properties with mean efficiency of ~99.8 % at 0.75 mA cm⁻² current density applied on 316L SS corrosion in acid media. The results of this study clearly ascertain that the polyaniline-MMT nanocomposite has an outstanding potential to protect 316L SS against corrosion in an acidic environment.