Preparation And Study On The Corrosion Resistance Of Carbon-Based Composite Waterborne Coatings

Carbon nanomaterials have attracted a wide range of research interest in the field of extensive research because of their unique structural characteristics since the discovery of them.In recent years,carbon nanomaterials have been applied carbon nanomaterials in anti-corrosive coatings to enhance the corrosion resistance of coatings.In this paper,the effects of structure of carbon materials on the corrosion resistance of waterborne coatings were studied.The main contents are as follows:1?The preparation and modification of carbon nanomaterials: Monolayer graphene oxide was prepared via the Hummers.Carbon nanotubes and carbon nano-onions were oxidized in the mixed acid to improve their dispersion in water.The AFM and SEM results showed that the obtained graphene was of multiple flaky layers;The thickness of prepared graphene oxide was about 1 nm;The length of the carbon nanotubes reached the micron level.The dispersion stability of the carbon nanotubes in water was improved by the oxygen-containing groups introduced in nanotubes after mixed acid treatment.The diameter of carbon nano-onions was between 50 and 200 nm,and the interlayer spacing was 0.334 nm.The structure of carbon nano-onions remained after the acid treatment,but the dispersion stability of carbon nano-onions was remarkably improved in water.2?Six kinds of carbon nanomaterials were dispersed into the industrial waterborne coating by high-speed stirring and ultrasonic to prepare composite coating.The composition of the industrial coatings was analyzed by infrared spectroscopy.The surface and cross-section morphology of the coatings were characterized.The wettability of the coatings evaluated by the contact angle test indicated that the addition of the carbon nanofillers hardly affects the wettability of the coating surfaces.3?The corrosion resistance of the coatings were evaluated by electrochemical impedance spectroscopy(EIS),polarization curve and salt water immersion test.The results showed that the corrosion resistance of the composite coatings increased first and then decreased with the increase of carbon nanofillers.The corrosion resistance of the coating could be improved by small amount of nanofillers.However,the nanofillers up to a certain content caused their aggregation,which reduce the corrosion resistance of the coatings reduced.The effect of nanofillers on the anti-corrosion of coatings is strongly depended on their morphology,particularly the aspect ratio.Higher enhancement on anti-corrosion resistance were providid by nanofiillers with higher aspect ratio.The electrochemical impedance spectroscopy revealed the best corrosion resistance for the composite coating with oxidized carbon nanotubes.The salt water immersion results showed that the corrosion spots on the surface of composite coatings containing nanofillers were fewer than that of the blank coating after immersing in the salt water for 20 days,which indicated that the corrosion resistance of the coatings were improved.But there were some differences between the electrochemical impedance spectroscopy and the salt water immersion test,which might be because of the different working condition.