Preparation and Anticorrosive Properties of Impermeable Composite Polyurethane Coatings

Abstract

Metal corrosion in marine atmospheric conditions is severe. Therefore, it is necessary to apply coating to surfaces of metal in this environment. In this research, two-dimensional lamellar graphene oxide was combined with TiO2/SiO2 nanoparticles to prepare polyurethane coatings. The anticorrosive behavior of the polyurethane composite coating treated with ultrasonication and high energy ball milling on carbon steel was evaluated. Results showed that after 28 d neutral salt spray test with 5% NaCl at 50 ℃, the surface of the coating samples treated with high-energy ball milling did not exhibit significant corrosion, in contrast to the unprotected carbon steel, indicating that the coating had a good protective effect on metal. The polyurethane composite coatings obtained from two treatment methods exhibited an increase of approximately three orders of magnitude in the modulus of low-frequency impedance |Z|0.01 Hz, and a nearly fourfold decrease in corrosion current density. Moreover, the impedance modulus of the composite coating produced by high-energy ball milling was two orders of magnitude higher than that obtained by ultrasonic treatment, and the corrosion currents were significantly lower.

Keywords

• impermeable coating|polyurethane coating|salt spray test|high energy ball mill|ultrasonic