Evaluation of Electrochemical and Anticorrosion Properties of Polyaniline-Fly Ash Nanocomposite

Abstract

In India, the thermal station generates approximately $6.9\times {10}^7$ tons of fly ash (FA) as a waste by-product. As part of this work, little attempt was made to produce useful materials from waste material. In our current research, polyaniline- (PANI-) fly ash (FA) nanocomposite (PFNC) was synthesized using an in situ polymerization method. The synthesized composites were characterized by employing advanced analytical, microscopic, and spectroscopic tools. The results of the X-ray diffraction (XRD) analysis confirm the effective reinforcement of FA into PANI in PFNC. The presence of functional groups in PFNC has been confirmed by Raman and FT-IR spectroscopic techniques. The SEM micrographs of the nanocomposite revealed the presence of agglomerated and fragmented structures in PFNC. The weight loss for PFNC was observed to occur in three stages as revealed by thermogravimetric analysis (TGA). UV-visible spectra for PFNC proved that FA stabilized the PANI in emeraldine form. Electrodynamic polarization studies were conducted to explore the corrosion resistance of nanocomposite-coated mild steel. The corrosion current density ( $i_{\text{corr}}$ ) for PFNC-coated mild steel (MS) specimens was found to decrease when compared to the bare substrate, indicating superior corrosion resistance in PFNC-coated substrate. Similarly, Tafel and cyclic polarization studies too confirmed superior anticorrosion property for MS coated with PFNC.