Anticorrosive polypyrrole/zirconium-oxide composite film prepared in oxalic acid and dodecylbenzene sulfonic acid mix electrolyte
By Menkuer, Merve; Ozkazanc, Hatice
Published in Progress in Organic Coatings
2020
Abstract
In this study, the surface of aluminum (Al) was coated by Polypyrrole (PPy) and Polypyrrole/Zirconium-oxide (PPy/ZrO2) films by using galvanostatic method in oxalic acid (OXA) and dodecylbenzene sulfonic acid (DBSA) mixture electrolyte. Structural and thermal characterization of the coatings were performed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and Thermogravimetric (TG) analyses, while surface morphologies were examined by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The anticorrosive effect of these coatings in a corrosive medium was investigated by Tafel Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. While the experimental data were evaluated with conventional equivalent circuit model, polarization resistance (Rp) values were estimated by using the Cole-Cole plotting. The PPy film increased the polarization resistance of the Al electrode 13 times, while the PPy/ZrO2 film increased it enormously by about 330 times. Furthermore, PPy/ZrO2 film provided almost 100 % protection efficiency against corrosion. The anti-corrosive performance of the coatings was associated with the anodic protection, barrier effect and prevention of charge transport by nanometal-oxide particles. It is thought that the Cole-Cole plotting approach could be a simpler and more useful method than the equivalent circuit fit method in calculating the Rp value for EIS curves containing inductive loop.