Optimized silica-based hybrid coatings for the protection of aluminum against chloride-rich environment


Sol–gel hybrid coatings have become one of the dominant platforms intended for anticorrosion applications. In this study, hybrid (silica/epoxy) ceramic coatings were designed and prepared using the sol–gel technique. 3-Glycidyloxypropyl trimethoxysilane and diglycidyl ether of bisphenol A (epoxy) were used as the main precursors, while 3-Aminopropyl triethoxysilane was involved as a coupling agent (linker) in different ratios along with diethylenetriamine as a tertiary hardener responsible for the hybrids curing. The formation of the silica as an inorganic network, epoxy as an organic network, and the interconnection between them was confirmed using FTIR. The scanning electron microscopy was utilized for investigating the morphology of the processed coatings. Moreover, the adhesion and the hardness of the formed coatings were evaluated as critical features for epoxy. Besides, thermogravimetric analysis was used to assess the thermal properties in order to overcome one of the disadvantages of epoxy coatings. Electrochemical Impedance Spectroscopy was performed in order to measure the capability of each combination for protection against corrosion. It was proven that the morphology of the product would vary in a great deal depending on the silica content, which plays a vital role in determining the mechanical and thermal properties of these coatings. Improvements could be witnessed by increasing the silica content up to a specific limit (ranging from 15 to 20%). However, a further increase in the silica content will lead to a noticeable drop in the corrosion resistance capability.


  • This study investigates a one-pot synthesis route for silica/epoxy coatings using the sol—gel technique, in order to achieve hybrids of molecular scale.

  • Multiple coupling agents were used, and the interactions of the prepared nanosilica to the bulk network were profoundly tracked.

  • Besides, mechanical and thermal assessments of the prepared coats were conducted, and the effect of the amount nanoparticles present on the performance was interpreted.

  • Moreover, the corrosion behavior was measured indicating the effectiveness of using such coats as barrier coats.

  • The study revealed the ability to tailor the composition of these hybrid networks in order to achieve a compromised combination of optimized performance serving most technical perspectives.

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Data availability

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.


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Correspondence to Mahmoud Y. Zoriany.

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Zoriany, M.Y., Nashaat, A., El-Shaer, Y. et al. Optimized silica-based hybrid coatings for the protection of aluminum against chloride-rich environment. J Sol-Gel Sci Technol 94, 257–269 (2020). https://doi.org/10.1007/s10971-020-05227-w

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  • Sol–gel
  • Silica
  • Anticorrosion
  • Epoxy
  • Hybrid
  • Aluminum