| Corrosion of metals is a widespread phenomenon in all areas of industrial production.The most used anti-corrosion method is the coating of organic coating layers.Conventional organic coatings have a number of defects that affect their corrosion resistance life and therefore have a large scope for improvement.Graphene is regarded as a new material with broad application prospects for corrosion protection due to its unique two-dimensional structure and very excellent barrier properties.Currently,the annual production of graphene has reached the hundred-ton level,which means that graphene has entered the commercial field and can be used in anti-corrosion coatings.The graphene’s industrial production is usually done by redox method,and the obtained graphene contains a small amount of oxygen.In addition,the unique twodimensional structure of graphene and its own π-π interaction make it easy to agglomerate in coatings,so graphene has problems such as poor hydrophobicity and poor dispersion in coatings.In this paper,we explore the enhancement of graphene materials on the anti-corrosion ability of commercially available organic coatings from the perspective of enhancing the anti-corrosion performance of coatings by preparing and modifying graphene.Thermally reduced graphene oxide was prepared and modified by two methods to obtain graphene with high hydrophobicity and good dispersion to enhance the anti-corrosion ability of organic coatings.The main work was done as follows.（1）Graphene was prepared by the thermal reduction method,and the effect of reduction temperature on the structure and properties of graphene was investigated,it was found that the high temperature is beneficial to the removal of oxygen-containing groups,but it causes the increase of defects in graphene.A series of TRGO composite coatings were prepared,and the results of polarization curve test experiments showed that graphene at a reduction temperature of 800℃ had the best enhancement effect on the corrosion resistance of organic coatings,which was attributed to the fact that TRGO-800 had fewer oxygen-containing groups and defects,and the largest specific surface area.The effect of graphene additions on the anti-corrosion performance of organic coatings was investigated,and the results of artificially simulated seawater immersion and electrochemical tests showed that the optimal mass fraction of TRGO additions was 0.1%.short-term immersion of TRGO composite coatings does not render the coating anti-corrosion ineffective,and the effect of TRGO is to lengthen the diffusion path of corrosive media and extend the time for corrosive media to enter the metal substrate.（2）The grafting of dodecyl chains in thermally reduced graphene oxide by Michael nucleophilic addition gives TRGO hydrophobicity.The conditions of the grafting reaction were compared,and it was found that the alkylated graphene prepared by triethylamine as a catalyst had the best hydrophobicity with a water contact angle（CA）as high as 144°,and the CA of the composite coating was enhanced by 15°compared with that of the pure epoxy coating by adding it to the organic coating.The electrochemical test results showed that the impedance modulus and self-corrosion current of LRGO-B/EPs were enhanced by three orders of magnitude compared with EPs,which was attributed to the larger specific surface area and stronger hydrophobicity of LRGO.（3）Grafting of silane coupling agent on commercial graphene（SE1232）through a two-step chemical reaction resulted in good dispersion and hydrophobicity of graphene in the organic coating.The contact angle test showed that the CA of siloxanemodified graphene（Si G）was 132°,and the CA of Si G/EPs composite coating was improved by 10° compared with EPs,showing better hydrophobicity.Si G can significantly improve the corrosion resistance of coatings due to its strong hydrophobicity and dispersion. |
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