Anticorrosion behavior of superhydrophobic particles reinforced epoxy coatings for long-time in the high salinity liquid

The low cost and excellent properties make Al2O3 particles a great potential in developing advanced epoxy composites. However, it's a big challenge to disperse the particles into epoxy matrixes in molecular-level. In this work, superhydrophobic Al2O3 particles, which was dispersed with mechanical method, were developed as reinforced particles for epoxy coating to develop the anti-corrosion under long-time exposure to solution of seawater salinity. The silane functionalized Al2O3 (SF-Al2O3) particles exhibited a water contact angle of 156.5 degrees. Electrochemical testing including open circuit potential, impedance and phase angle measurements showed that SF-Al2O3 epoxy has better corrosion resistance in high salinity solution than original epoxy, while the unfunctionalized Al2O3 (UF-Al2O3) coating got failure after 36 days (d) of immersion. Scanning electron microscope analysis revealed a very good condition of the SF-Al2O3 epoxy coating after 144 d of immersion. It is clearly observed that silane-modified particles were very effective on the anti-corrosion protection property of composites in high salinity solution. There may be profound implication to design organic coatings reinforced by particles using simple mechanical stirring method.