The effects of carbon black in epoxy coating filled polyaniline/nano-zinc/carbon black on corrosion resistance

Abstract

The main objective of this research is to study the effects of polyaniline (PAni)/nano-zinc/carbon black/epoxy coating on the corrosion resistance of carbon steel substrate. The anticorrosion coating material was prepared by mixing the PAni, nano-zinc powder, carbon black and epoxy resin. The PAni content and nano-zinc powder content were fixed at 0.3 wt% and 1wt% while the carbon black contents were varied from 0, 0.5, 1 and 1.5 wt%. The PAni was synthesized via chemical method and characterized by Fourier Transformed Infrared (FTIR). The corrosion resistance of PAni/nano-zinc/carbon black/epoxy coated substrate was evaluated using immersion test and the interaction between the four components of coated material was analyzed by FTIR. Thermogravimetric analysis (TGA) is used to evaluate the thermal stability of the PAni/nano-zinc/carbon black/epoxy coating materials. Analysis of the absorption peaks in FTIR spectrum of synthesized PAni- ES has confirmed that the produced green powder was PAni. Conductivity test proved an acceptable conductivity of 0.6-0.9 S/cm. From the results, it was found that epoxy coating with PAni alone and nano-zinc powder alone have reduced the corrosion rate of epoxy coating. The combination of PAni and nano-zinc powder had further reduced the corrosion rate of coating materials. The PAni/nano-zinc/carbon black/epoxy coating material have increase the corrosion resistance of carbon steel substrate and the protection of corrosion is further increased with increasing of carbon black powder contents. FTIR analysis of final coating materials showed very similar absorption peaks in seven different coating compositions which proved that there is no chemical bonding to make shifting in peaks in comparison between different formulations. From TGA results, the onset degradation temperature increased with the incorporation of PAni, nano-zinc and carbon black.