Improving the corrosion protection properties of organically modified silicate–epoxy coatings by incorporation of organic and inorganic inhibitors

Organically modified silicate (ORMOSIL)–epoxy coatings were formed on aluminium alloy 2024-T3 in order to protect the substrates from corrosion. Organic and inorganic compounds, all known for their corrosion inhibition ability, were incorporated into the polymer matrix for the improvement of the corrosion resistance. The ORMOSIL–epoxy coatings were deposited via the dip-coating process. The properties of the coatings were investigated after 24 h of curing at 90 °C. The morphology of the coatings was examined by scanning electron microscopy (SEM). Their composition and structure were investigated by Fourier transform infrared spectroscopy (FT-IR) and energy dispersive X-ray analysis (EDX). The corrosion resistance of these coatings was investigated using electrochemical impedance spectroscopy (EIS). The results showed that the most effective corrosion protection ability was provided by the inorganic inhibitors and that an important role can be attributed to the cation in the nitrate salt.

► ORMOSIL–epoxy coatings were formed on AA2024-T3.
► Corrosion inhibitors incorporated into the polymer matrix.
► The incorporation of the inhibitors improved corrosion resistance of the coatings.