Hybrid Sol–Gel Silica Coatings Containing Graphene Nanosheets for Improving the Corrosion Protection of AA2024-T3

Abstract

In the present work, nanostructured graphene nanosheets were added to hybrid silica sols and deposited on aluminium alloy A2024-T3 to study the effect on the corrosion behaviour. Sols were prepared using tetraethyl-orthosilicate (TEOS), 3-glycidoxypropyl-trimethoxysilane (GPTMS) and a colloidal silica suspension (LUDOX) as silica precursors with adding chemically modified graphene nanosheets (GN-chem). The graphene nanosheets were modified through a straightforward and simple hydrothermal approach and then, dispersed into a silica sol (SiO2/GN-chem). ATR-FTIR was used to optimize the silica sol–gel synthesis and to confirm the cross-linking of the silica network. The corrosion behaviour of the SiO2/GN-chem coatings was also analysed by electrochemical measurement (potentiodynamic polarization) in 0.05 M NaCl solution. The results showed that the incorporation of modified graphene nanosheets into hybrid silica sol–gel coatings affected the corrosion properties of the substrates. An improvement in the corrosion resistance was observed likely due to the enhanced barrier property and hydrophobic behaviour obtained by incorporation of GN-chem and colloidal silica nanoparticles.

Improving corrosion protection of Mg alloys (AZ31B) using graphene‐based hybrid coatings

“…The sol was stirred for 15 min at room temperature. Finally, 0.38 mol of acidulated water (1 M HCl) was added dropwise to the solution under continuous stirring and maintained at 40 • C under reflux system for 24 h. Graphene nanosheets (GN) were chemically modified following the process described in the previous work 16 being denoted as GN-chem. GN-chem based GT sol (GT/GN-chem) was prepared by adding a small amount of GPTMS (160 µL) to a solution of GN-chem in tetrahydrofuran (THF, 25 mg/ml) and stirred for 6 h at room temperature and for 1 h at 85 • C under reflux.…”

“…Nevertheless, to the best of our knowledge, no extensive investigations on the fabrication of graphene-SiO 2 hybrid coatings on such alloys were performed and reported. In a previous article, 16 we reported on the addition of modified graphene nanosheets to hybrid silica sol-gel coatings for improving the corrosion performance of aluminum alloys (AA2024-T3), proposing a novel coating strategy.…”

A novel bioactive glass/graphene oxide composite coating for a polyether ether ketone‐based dental implant

“…It was expected that the hydrolyzed TEOS species would react with the functional groups of GO. Therefore, the shifting of Si‐O‐Si asymmetrical stretching band to a large wavenumber might be ascribed to the chemical bond between the functional groups of GO and the silica network [61].…”

Review of Recent Developments in the Formulation of Graphene-Based Coatings for the Corrosion Protection of Metals and Alloys

“…More recently, GO has been incorporated into this sol-gel network to give further improvement in the corrosion protection of the coatings [197]. Sol-gels modified with GO [198][199][200][201], functionalised GO [202][203][204] and GO loaded corrosion inhibitors [205,206] have all been employed to enhance the protective properties of the coatings. For example, Parkhizer et al [202] incorporated silane functionalised GO nanosheets into a silane coating and compared this coating with the non-functionalised GO-based silane coating.…”