Evaluation of an Advanced Self Healing and Highly Durable Corrosion Protective Epoxy Coating Modified with Poly(Aniline-co-Pentafluoroaniline)/ ZrO2 Nanocomposite on Mild Steel

摘要

Background: Present work demonstrates the development of highly durable anticorrosive coating based on epoxy reinforced poly(aniline-co-pentafluoro aniline)/ZrO2 nanocomposite which improves the mechanical and anticorrosive properties of the coating and provides an excellent barrier property against corrosive atmosphere. Method: Conducting copolymer nanocomposite based on aniline and 2,3,4,5,6 pentafluoro aniline and incorporation of ZrO2 nanoparticles in copolymer was carried out by insitu chemical oxidative polymerization using ammonium persulfate as an oxidant and ortho phosphoric acid as a dopant. Coating of synthesised nanocomposite on iron surface was carried out by powder coating technique. Coated iron samples were characterized by different techniques such as Fourier Transform Infrared (FTIR) Spectroscopy, Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM), Energy dispersive x-ray (EDX) studies, Transmission Electron Microscopy (TEM) and contact angle measurements. Durablity of coating was investigated by physico-mechanical testing as per ASTM standard. Anticor-rosion studies were carried out by electrochemical studies and salt spray methods. Results: Average dimension of copolymer/ZrO2 nanocomposite was found to be 20 nm. Contact angle of copolymer nanocomposite based coating was found to be 102°. Electrochemical studies of the coated iron revealed remarkable reduction of corrosion current density from 89 uA/cm2 to 0.8 uA/cm2 and showed corrosion preventive efficiency upto 99% in saline atmosphere, which indicates the positive impact, both in the barrier properties and corrosion protection behavior due to copolymer/ZrO2 nanocomposite. Salt spray test of coated mild steel surface showed an excellent corrosion protective performance offered by the eopolymer/ZrO2 nanocomposites. Impedance spectra of copolymer /ZrO2 nanocomposite modified epoxy coating also indicate its self-healing property. Conclusion: Poly(aniline-co-pentafluoro aniline)/ZrO2 nanocomposites were successfully coated on the iron surface and FTIR, TGA, SEM, EDX and TEM studies confirmed the formation and interaction of ZrO2 nanoparticles in copolymer. The coating showed uniform thickness and a lack of cracks, therefore it was found to be an excellent oxidation and corrosion resistance material under harsh chlorine ion environment which may open new option in applications for the marine engineering materials which require very high salt resistance.