An assessment of the corrosion protection of AA2024-T3 treated with vinyltrimethoxysilane/(3-glycidyloxypropyl)trimethoxysilane

• Vinyltrimethoxysilane (VTMS)/3-glycydoxypropyltrimethoxysilane (GPTMS) film on AA2024.
• Modified films based on combination of silica matrix and phosphonic acid (PA).
• PA action occurs in the interface film/metallic surface.
• Silica nanoparticles promote the improve of barrier properties of silica/PA films.
• This system is very efficient for corrosion protection.

The protection of aluminum alloy 2024-T3 imparted by (3-glycidyloxypropyl)trimethoxysilane (GPTMS)/vinyltrimetoxysilane (VTMS) sol–gel films and the incorporation of ethylenediamine tetra(methylenephosphonic acid) (EDTPO) into silica matrix has been investigated. The corrosion behavior in chloride solution depends on the GPTMS/VTMS ratio. The protective performance has been improved by achieving a better coverage surface through the addition of EDTPO to sol–gel films. Nevertheless, EDTPO catalyzes the opening of epoxy ring, promoting the hydrophilic character of the silica surface. On the other hand, the incorporation of functionalized silica nanoparticles into silica/EDTPO matrix affords long-term corrosion protection due to the enhancement of barrier properties.