Synthesis of PDA-BN@f-Al2O3 hybrid for nanocomposite epoxy coating with superior corrosion protective properties

A novel PDA-BN@f-Al 2 O 3 nanohybrid was synthesized by depositing Al 2 O 3 nanoparticles modified with γ $\gamma$ -Aminopropyltriethoxysilane (KH550) on the surface of hexagonal boron-nitride (h-BN) sheets covered with polydopamine (PDA). Then, PDA-BN@f-Al 2 O 3 hybrids was dispersed in epoxy resin to prepare composite coating samples. Many characterizations revealed that the functionalized Al 2 O 3 successfully deposited on the surface of PDA-BN platelets and PDA-BN@f-Al 2 O 3 hybrids showed good dispersibility in the epoxy resin, and the interfacial adhesion between hybrids and epoxy matrix was improved. Furthermore, the effects of Al 2 O 3 , h-BN and various mixtures of PDA-BN@f-Al 2 O 3 hybrids at a low weight fraction of 1 % on the corrosion resistance of epoxy coating were studied by electrochemical measurement and salt spray test. The potentiodynamic polarization test revealed that PDA-BN@f-Al 2 O 3 hybrids have a corrosion inhibitive performance. Moreover, the coating resistance of PDA-BN@f-Al 2 O 3 (3:1)/epoxy was enhanced by three orders of magnitude compared with neat epoxy after 5 d immersion. This study provides a promising application prospect for the development of superior metal protective organic coatings.