Preparation And Properties Of Waterborne Epoxy Zinc Rich Coatings Modified By Reduced Graphene Oxide And Graphene Oxide

Graphene materials as functional fillers can improve the density of anti-corrosion coating and hinder the diffusion of corrosive medium in the coating.In this paper,using the excellent properties and structural characteristics of graphene materials,the waterborne epoxy zinc rich coating is modified to prepare a composite waterborne epoxy zinc rich coating with low zinc powder content but improved anti-corrosion performance.The research work mainly includes two parts:The first part is the preparation of reduced graphene oxide/waterborne epoxy zinc rich coating.Graphene oxide was reduced by vitamin C,and the effects of reduced graphene oxide and zinc addition on the properties of reduced graphene oxide/waterborne epoxy zinc-rich coatings were studied.The composite coating was characterized and analyzed by fourier infrared spectroscopy(FTIR),scanning electron microscopy(SEM),mechanical properties test,electrochemical impedance spectroscopy(EIS),contact angle test and neutral salt spray test.The results show that vitamin C can remove most of the oxidation functional groups of graphene oxide.When 0.4% reduced graphene oxide is added and zinc content is 70%,the neutral salt spray resistance time of the prepared composite coating can reach 1272 h,the coating hardness is 4h,the impact strength is 50 cm,the adhesion is grade 0 and the contact angle is 85.7°.The electrochemical impedance spectrum,capacitive reactance arc radius and impedance modulus of the coating before and after immersion in 3.5% Na Cl solution are the largest,which reduces the zinc content of the coating by 10%,and the salt spray resistance time is prolonged by 312 h.The second part is the preparation of graphene oxide/waterborne epoxy zinc rich coating.The effects of different oxidation time of graphene oxide,different graphene oxide and zinc addition amount on the properties of graphene oxide/waterborne epoxy zinc rich coating were studied.The surface morphology and corrosion process of the composite coating were characterized and analyzed by fourier infrared spectroscopy(FTIR),scanning electron microscopy(SEM),mechanical property test,electrochemical impedance spectroscopy(EIS),contact angle test and neutral salt spray test.The results show that when 0.3% graphene oxide with oxidation time of 30 min and zinc content of 60%,the neutral salt spray resistance of the composite coating can reach 1320 h,the hardness of the coating is 4h,the impact strength is50 cm,the adhesion is grade 0 and the contact angle is 86.4°.The electrochemical impedance spectrum,capacitive reactance arc radius and impedance value modulus of the coating before and after immersion in 3.5% Na Cl solution are the largest,which reduces the zinc content of the coating by 20%,and the salt spray resistance time is prolonged by 360 h.