Preparation and anti-corrosion performances of nano-graphite/polyurethane composite coatings

In order to investigate high performance protective coatings for electric power fittings, nano-graphite/polyurethane composite paintings with different nano-graphite contents were prepared firstly using hydroxyl acrylic resin and isocynate as main film-forming substances as well as nano-graphite as fillers. Then, the nano-graphite/polyurethane composite paintings were applied on electric hot dip galvanized steel, and nano-graphite/polyurethane composite coatings were obtained after solid drying. Finally, the mechanical properties and abrasion resistance of nano-graphite/polyurethane composite coatings were tested, and the anti-corrosion performances of nano-graphite/polyurethane composite coatings were investigated using simulated acid rain tests, neutral salt spray tests and electrochemical impedance spectroscopy (EIS). The results show that the adhesion between coating and hot dip galvanized steel is improved after adding nano-graphite, the abrasion resistance of nano-graphite/polyurethane composite coating whose nano-graphite content is 2.0wt% is improved by 92% comparing with the blank coating without adding nano-graphite, and the distribution of nano-graphite in the coating is relatively uniform, which shows good anti-corrosion performance. The conclusions obtained show that the addition of nano-graphite with suitable amount in coatings can enhance the abrasion resistance and anti-corrosion performances of coatings, thus the coatings can be used for surface protection of electric power fittings.