Wang, J.; Qi, Y.; Zhao, X.; Zhang, Z. Electrochemical Investigation of Corrosion Behavior of Epoxy Modified Silicate Zinc-Rich Coatings in 3.5% NaCl Solution. Coatings2020, 10, 444.
Wang, J.; Qi, Y.; Zhao, X.; Zhang, Z. Electrochemical Investigation of Corrosion Behavior of Epoxy Modified Silicate Zinc-Rich Coatings in 3.5% NaCl Solution. Coatings 2020, 10, 444.
In order to develop waterborne silicate anticorrosive coatings to replace solvent-based anticorrosive coatings used widely in ship’s industry, epoxy modified silicate emulsions were synthesized with different content of epoxy resin, then aqueous silicate zinc-rich coatings were prepared with synthesized silicate emulsion, triethylamine and zinc powder. The influence of the content of epoxy on the properties and chemical structure of modified emulsion, mechanical properties of silicate coatings, and the corrosion behavior of silicate zinc-rich coatings in 3.5% NaCl solution were investigated. The coating samples on steel were measured by immersion test, Tafel polarization test and electrochemical impedance spectroscopy (EIS) test with different immersion time. The results showed that epoxy modified silicate emulsions were successfully synthesized. With the increase of epoxy content, the viscosity and the solid content of modified emulsion increases, the impact resistance of the silicate coating raises, the pencil hardness decreases, but the adhesion is not affected. Epoxy modification can reduce to s certain extent the corrosion driving force of zinc rich coating and increase the impedance of the zinc-rich coating decreases with the increase of immersion time in 3.5% NaCl solution. With the increase of the epoxy content, the resistance value of the zinc-rich coating increases, indicating the ability of the coating to resist corrosive media is enhanced.
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