Materials (Oct 2019)

Electrochemical Study of a Hybrid Polymethyl Methacrylate Coating using SiO<sub>2</sub> Nanoparticles toward the Mitigation of the Corrosion in Marine Environments

  • José Maya-Cornejo,
  • Francisco J. Rodríguez-Gómez,
  • Gustavo A. Molina,
  • Juan Galindo-de-la-Rosa,
  • Janet Ledesma-García,
  • Ángel R. Hernández-Martínez,
  • Rodrigo Esparza,
  • Ramiro Pérez,
  • Miriam Estévez

DOI
https://doi.org/10.3390/ma12193216
Journal volume & issue
Vol. 12, no. 19
p. 3216

Abstract

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The demand for hydrophobic polymer-based protective coatings to impart high corrosion resistance has increased recently. The increase of the hydrophobicity in a hybrid coating is a new challenge, for that reason and in order to protect a metallic surface of oxidant agents, a poly (methyl methacrylate) (PMMA) coating with the addition of a different amount of silicon dioxide (SiO2) was developed. The hybrid coating was applied on a sample of stainless steel AISI 304 by the dip-coating method. The characterization of the coatings was determined by electrochemical impedance spectroscopy and with a scanning electrochemical microscopy. The best coatings were PMMA and PMMA + SiO2 0.01% that exhibits a real impedance in the Nyquist diagram of 760 and 427,800 MΩ⋅cm2, respectively, and the modulus of the real impedance in the Bode diagram present values of 2.2 × 108 and 3.3 × 108 Ω⋅cm2. Moreover, the phase angle presents constant values around 75° to 85° and 85° for the PMMA and PMMA + SiO2 0.01%, respectively. Moreover, the values of the real resistance for the PMMA + SiO2 0.01% coating present values in the order of Mega-ohms despite the coating exhibits an artificial defect in their surface. The contact angle test showed that the hydrophobicity of the hybrid PMMA + SiO2 0.01% coating is higher than that of the pure PMMA coatings. The hybrid PMMA + SiO2 coatings developed in this work are a very interesting and promising area of study in order to develop efficient products to protect metallic surfaces from corrosion phenomenon.

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