Synergistic enhancement of epoxy coatings with silane-modified SiO2@GO nanohybrids: Superior mechanical strength and corrosion resistance

Epoxy resin (EP) coatings are widely employed for metal corrosion protection, yet their long-term performance is often compromised by inherent brittleness, microporosity, and poor dispersion of nanofillers. In this work, nano-sized SiO2 was efficiently modified using three silane coupling agents (APTES, GLYMO, MAPTES), with APTES exhibiting the highest modification efficiency, reducing surface hydroxyl density to 0.59/nm2 and achieving a water contact angle of 132.7°. The optimized SiO2 was then anchored onto graphene oxide (GO) sheets to form SiO2@GO nanohybrids with tunable mass ratios. At a SiO2:GO ratio of 1:6, the hybrid exhibited a maximized interlayer spacing of 1.02 nm and uniform SiO2 dispersion, significantly enhancing its compatibility with the epoxy matrix. With the addition of 1.0 wt% SiO2@GO composite, the EP coating demonstrated a remarkable static water contact angle of 142.8°, a reduction by over 99% in corrosion rate (1.87×10-3 mm/year) compared to pure EP coating(0.41 mm/year), and a high low-frequency impedance modulus of 1.88×106 Ω·cm2 after 30 days in 3.5% NaCl. The dual mechanisms of enhanced hydrophobicity and tortuous diffusion pathways synergistically improved the coating's barrier properties. This study presents a rational design strategy for high-performance anti-corrosion coatings suitable for harsh environments.