Studies on coatings containing nano‐zinc oxide for steel protection

• Published in: Materials and corrosion 2021-05, Vol.72 (5), p.859-867
• Main Authors: Shmait, Abeer, Awad, Ramadan, Rahal, Hanan T., Azouri, Michele, Abdel‐Gaber, Ashraf M.
• Format: Article
• Language: English
• Subjects: Circuits; Corrosion prevention; Corrosion resistance; Electrochemical impedance spectroscopy; epoxy; Fourier transforms; Infrared spectroscopy; Low carbon steels; Mechanical properties; mild steel; Modulus of elasticity; Morphology; Nanoparticles; Panels; polyurethane; Polyurethane resins; Scanning electron microscopy; Spectrum analysis; Tensile strength; Tensile stress; Zinc coatings; Zinc oxide; Zinc oxides; ZnO nanoparticles
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202012010

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized using the coprecipitation method. The resulting NPs were characterized by X‐ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The surface morphology of the coatings has been characterized by scanning electron microscopy (SEM). SEM images show a uniform and homogeneous distribution of ZnO‐NPs in polyurethane (PU) coatings while aggregates appear in epoxy coatings. Using tensile stress–strain test, the effect of the addition of ZnO‐NPs on the mechanical properties of PU and epoxy coatings was examined. The addition of ZnO‐NPs has enhanced the Young's modulus and the tensile strength of PU and epoxy coatings. Through the open‐circuit potential and electrochemical impedance spectroscopy measurements, the anticorrosive properties of PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs have been investigated in 0.5 M NaCl solution. Nyquist impedance plots for PU and epoxy coatings in PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs were tested in the absence and presence of ZnO‐NPs have different responses. It has been shown that the dispersion of ZnO‐NPs significantly improves the anticorrosive performance of PU coatings. A PU coating containing 700 mg/kg ZnO‐NPs is recommended to achieve better mechanical properties and corrosion resistance. Zinc oxide (ZnO) nanoparticles were synthesized using coprecipitation method. Nyquist impedance plots for polyurethane (PU) and epoxy coatings in the absence and presence of ZnO nanoparticles (NPs) have different responses. It has been shown that ZnO‐NPs significantly improve the microstructure and anticorrosive performance of PU and epoxy coatings.