| Coating protection is the most widely used technique in the field of metal corrosion protection.Epoxy resin（EP）is often used as anticorrosive coatings due to its unique tensile strength,modulus,durability at high and low temperatures,strong adhesion,low shrinkage upon cure,good flexibility and chemical resistance.However,the anti-corrosion effect of the traditional epoxy resin coating has been unable to meet the requirements of today’s industrial development.Therefore,improving the anti-corrosion performance of epoxy resin has become one of the research hotspots in the field of metal anti-corrosion.Graphene oxide（GO）has a lamellar structure,which has a good barrier property against water,O2 and ions,etc.It can be used as a functional filler to enhance the anti-corrosion performance of epoxy resin.In this paper,graphene oxide with excellent barrier property was used to improve the anti-corrosion performance of epoxy resin coating.The preparation process of GO/EP anticorrosive coatings was studied.The main work and results of this paper are as follows:（1）Using graphite powder as raw material,GO was prepared by the modified Hummers method.Then A-GO was synthesized by the modification reaction between silane coupling agent KH550 and GO,and G-GO was produced by the modification reaction between silane coupling agent KH560 and GO.The differences of GO,A-GO and G-GO in structure,morphology,thermal stability and dispersion were compared by test methods such as XRD,FTIR,SEM,TEM,TG and dispersibility.In the FTIR spectra of F-GO,the peaks of Si-O-Si and Si-O-C proved that silane coupling agents was successfully modified GO.Compared with GO,A-GO and G-GO possessed larger interlayer distance.In the XRD spectra,A-GO and G-GO had wider and disordered diffraction peak than that of GO,which inferred the decreased crystallinity and increased peel.A-GO and G-GO had a plannar structure with a small sheet area.The thermostability and dispersibility of A-GO and G-GO were higher than that of GO.（2）A-GO/EP composite coatings and G-GO/EP composite coatings were prepared with A-GO and G-GO as the fillers.The effect of filler content on the corrosion resistance of coatings was investigated.Electrochemistry and salt spray tests were conducted which showed that,in the A-GO/EP composite coatings,0.10%A-GO/EP composite coating had a good anti-corrosion properties.Its corrosion current density was 2.16E-9 A/cm2,which was about two orders of magnitude lower than pure EP coating.Its corrosion potential was-0.618 V,which was 85 mV higher than the pure EP coating.Its corrosion rate was reduced from 1.99E-3 mm/year to2.54E-5 mm/year,and the coating resistance increased from 1.44E+3Ωto 1.51E+5Ω..In the G-GO/EP composite coatings,the 0.20%G-GO/EP composite coating had a good anti-corrosion properties.Its corrosion current density was 7.23E-9 A/cm2.The corrosion current density of the pure EP coating was about 23 times of that of it.Its corrosion potential is-0.650 V,which was 53 mV higher than the pure EP coating.Its corrosion rate was reduced from 1.99E-3 mm/year to 8.48E-5 mm/year,and the coating resistance increased from 1.44E+3Ωto 3.25E+4Ω.That is,when the addition amount of A-GO and G-GO was the optimal value,the anti-corrosion performance of A-GO/EP composite coating was better than that of G-GO/EP composite coating.The hardness test results showed that the hardness of the pure EP coating was 2H,and the hardness of the 0.10%A-GO/EP and 0.20%G-GO/EP composite coatings were increased to 3H.（3）On the basis of 0.10%A-GO/EP coating,A-GO/SiO2/EP composite coatings and A-GO/TiO2/EP composite coatings were prepared by ultrasonic stirring method with A-GO/SiO2 and A-GO/TiO2 as the fillers.MA-GO:MSiO2 and MA-GO:MTiO2 were screened.Electrochemistry and salt spray tests were conducted which showed that when MA-GO:MSiO2 was 1:2,A-GO/SiO2/EP composite coatings had better corrosion resistance.When MA-GO:MTiO2 was 3:1,A-GO/TiO2/EP composite coating had good corrosion resistance.Compared with the 0.10%A-GO/EP coating,the addition of nano-SiO2 particles and nano-TiO2 particles failed to significantly improve the corrosion resistance of the coating,but the corrosion resistance of the Ti3:1 coating was better than that of the Si1:2 coating.（4）Nano-FTiO2 particles were produced by the modification reaction between silane coupling agent KH550 and nano-TiO2 particles.On the basis of0.10%A-GO/EP coating,A-GO/FTiO2/EP composite coatings were prepared by ultrasonic stirring method with A-GO/FTiO2 as the fillers.MA-GO:MFTiO2 were screened.Electrochemistry and salt spray tests were conducted which showed that the anti-corrosion performance of the composite coating was greatly improved after adding nano-FTiO2 particles.When MA-GO:MFTiO2 was 2:1,A-GO/FTiO2/EP composite coating had good corrosion resistance.Its corrosion current density was6.88E-12 A/cm2,which was about three orders of magnitude lower than the0.10%A-GO/EP composite coating.Its corrosion potential was-0.561 V,which was57 mV higher than 0.10%A-GO/EP composite coating.Its corrosion rate was reduced from 2.54E-5 mm/year to 8.07E-8 mm/year,and the coating resistance increased from1.51E+5Ωto 3.48E+7Ω.The hardness test results showed that the hardness of the0.10%A-GO/EP coating was 3H,and the hardness of the FTi2:1 composite coating was increased to 4H. |
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