Zirconium-Doped Ceria Nanoparticles as Anticorrosion Pigments in Waterborne Epoxy–Polymer Coatings

• Published in: ACS applied nano materials 2021-01, Vol.4 (1), p.834-849
• Main Authors: Joseph, Antony, John Mathew, Kevin P, Vandana, Sajith
• Format: Article
• Language: English
• ISSN: 2574-0970; 2574-0970
• DOI: 10.1021/acsanm.0c03162

The use of anticorrosion pigments in polymeric coatings is an effective way for the prevention of corrosion of metals. Ceria nanoparticle-based pigments are excellent replacement for conventional chromate-based inhibitors that create severe toxicity and health hazards. The corrosion inhibition mechanism of ceria is associated with its Ce4+ ↔ Ce3+ redox shuttle and ability to form insoluble precipitates over the metallic substrate. Zirconium doping in ceria can enhance its redox properties by creating a large number of oxygen vacancies. However, corrosion inhibition properties of zirconium-doped ceria are not studied yet. In the present work, ceria–zirconia solid solutions (Ce x Zr1–x O2 nanoparticles) with different doping concentrations of Zr have been prepared using coprecipitation synthesis. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy studies revealed the formation of ceria–zirconia solid solutions with increased oxygen defect density. Thermogravimetric analysis exhibited enhanced oxygen storage capacity for Ce–Zr solid solutions. Ce x Zr1–x O2 nanoparticle-filled waterborne epoxy resin coating has been prepared on a mild steel substrate using the spin-coating technique. Electrochemical corrosion measurements were employed to analyze the corrosion inhibition properties of the coatings. Tafel polarization results and electrochemical impedance spectroscopy analysis show excellent corrosion resistance for zirconium-doped ceria nanoparticle-filled epoxy coating. The corrosion resistance of the zirconium-doped ceria-epoxy coating increased with an increase in the doping concentration of Zr for Ce-rich Ce–Zr solid solutions (0.6 ≤ x ≤ 0.8). The corrosion inhibition property of ceria–zirconia solid solutions is attributed to the improvement in their redox properties due to a large number of oxygen vacancies.