Hydrophobic versatile epoxy coatings modified with AgO-based composite for anticorrosion and antifouling applications

Biofouling and corrosion are the important factors that reduce the service life of Q235 carbon steel utilized as structural materials in marine exploitation. Herein, AgO-based composite as effective filler was introduced into epoxy matrix, and a series of versatile epoxy coatings with enhanced antifouling properties and corrosion resistance were electrostatic sprayed on Q235 carbon steel substrate. The microstructure, pore structure and filler distribution of prepared versatile epoxy coatings were analyzed by SEM, EDS, laser scanning confocal microscope and mercury intrusion method. It was found that the AgO-based composite filled a part of micropores generated from the cross-linking and curing of epoxy matrix. The AgO-based composite was introduced to reduce the surface energy and construct a large number of micro-convex structures on the coating surface. As the addition amount of AgO-based composite increased, the porosity and surface energy of the coatings was firstly reduced and then increased, while the change trend for the number of micro-convex structures was reverse. The hydrophobic versatile epoxy coating with 1.5 wt% AgO-based composite had the minimal porosity of 1.527%, the lowest surface energy of 26.495×10 -3 J.m -2 , the highest surface roughness of 6.698 μm and water contact angle of 91.8°. More importantly, the hydrophobic versatile epoxy coating with 1.5 wt% AgO-based composite had the optimal corrosion resistance, which exhibited the highest impedance. No corrosion was observed on this coating after 33 days immersion in seawater. In addition, the versatile epoxy coatings exhibited the enhanced antifouling properties with increasing AgO-based composite addition amount.