Application of Electrochemical Techniques on Study of Effect of Nano-ZnO in Conductive Polyaniline Containing Zinc-Rich Primer

Ximing Li,Homero Castaneda

doi:10.1155/2018/7160381

Abstract

Effect of zinc oxide nanoparticles on anticorrosion performance has been studied in conductive polyaniline containing zinc-rich primer in 3.5 wt% NaCl solution, using Electrochemical Impedance Spectroscopy (EIS) and localized electrochemical Scanning Vibrating Electrode Technique (SVET). The results showed that the addition of nano-zinc oxide particles in conductive polyaniline containing zinc-rich primer made the reaction of zinc more stable and slower, further increasing the effective cathodic protection period. EIS and SVET results confirmed that three performance evolution stages were obtained for zinc-rich primer being immersed in 3.5 wt% sodium chloride solution.

Highlights

Zinc-rich epoxy primer (ZRP) has been used as anticorrosion primers since the 1930s [1, 2], highly recommended for offshore environments, refineries, power plants, bridges, and so forth
The small amount of conductive PAni improved the Zm-to-Zn condition of the ZRP, which has been discussed in previous study [8], while the addition of nano-ZnO particles in PAni-ZRP increased the dry coating resistivity with large derivation, probably because of the addition of ZnO and the combination of ZnO and PAni which counteract the effect of conductive polyaniline in ZRP
Considering the signal of current in the mapping, the negative current value is correlated with cathodic reaction, mainly occurring on steel surface, while the positive current values are correlated with anodic reaction, that occur at the zinc primer surface

Summary

Introduction

Zinc-rich epoxy primer (ZRP) has been used as anticorrosion primers since the 1930s [1, 2], highly recommended for offshore environments, refineries, power plants, bridges, and so forth. Mostafaei and Nasirpouri [9] synthesized a series of conducting PAni-ZnO nanocomposites materials, and the study results showed that the addition of ZnO nanorods and PAni significantly improved the barrier and corrosion protection performance of the epoxy coating. Scanning Vibrating Electrode Technique (SVET) is a powerful tool to permit a better understanding of the mechanisms and processes of corrosion at defects and underneath coatings [28]. This technique can provide valuable information of the electrochemical interactions between a coating and its substrate at a defect. Different electrochemical microscopy techniques were used in this work, including electrochemical and localized scanning vibrating electrode spectroscopy technique

Experimental Design

Testing Environments and Methods

Results and Discussion

SVET Results and Discussion

Conclusion