Preparation And Properties Of Graphite Nanosheets/Epoxy Compound Anticorrosive Coatings

Metallic materials play an important role in the industry.The corrosion of metals exists in various fields and it causes a great harm to the development of national economy.Therefore,the research of anti-corrosion coatings is very important.Because of the large amount of ions contained in the water-soluble paint,the anti-corrosion ability of the coating is substrate,the anti-corrosion coatings are still based on organic solvents nowadays.Graphite nanosheet,graphene and other graphite materials have lamellar structure,have good stability and barrier properties with water,oxygen and ions,and it have unique dielectric effect in the polymer,as anti-corrosion coating has broad prospects.In this study,use the graphite nanosheets as filler,aqueous epoxy emulsion as a resin matrix,prepared graphite nanosheets/epoxy composite anticorrosive coatings,the curing agent,graphite nanosheets and modified graphite nanosheets dosage of composite coatings curing,Anti-corrosion,mechanical properties and other effects,and analysis of anticorrosive graphite coating anti-corrosion mechanism.It was found that when the dosage of curing agent to epoxy resin was 1:1,the surface dry time was the shortest,3.5 h;the salt spray resistance was longest,24 h;The pencil hardness was 4 H and the adhesion was level 2;The results of FT-IR showed that the solidification time of the coating was 54 h.Through the salt spray test,tafel polarization curve test analysis the impact of the amount of graphite nanosheets on the corrosion resistance of the coating,the results show that:when the amount of graphite nanosheets epoxy resin 4 wt%,the performance of graphite nanosheets/epoxy coating is better,salt spray time was longest,240 h,the corrosion potential was the highest,-0.7637 V,and the corrosion current is 5.568E-5 A/cm-1;Analysis the anti-corrosion mechanism by means of metalloscope,SEM,dielectric constant.The study found that the corrosion mechanism of graphite nanosheetst/tepoxy coatings was both the use of graphite nanosheet's isolation ability and chemical stability,isolation of the water and oxygen to achieve the physical isolation mechanism,it also formation a micro-capacitance model in epoxy resin to improve the dielectric constant of the film by block the electrochemical pathway.The graphite nanosheet was modified by KH550,and the influence of the added amount of moditied graphite nanosheet on the anti-corrosive coating was investigated by salt spray test,tafel polarization curve test and dielectric constant test.The results showed that:When the amount of graphite nanosheets epoxy resin 3.2 wt%,the salt spray resistance was longest,270 h;The corrosion potential was the highest,-0.6832 V,and the corrosion current is 2.229E-5 A/cm-1;The dispersion effect of coatings with different modified graphite nanosheets was characterized by metalloscope,SEM,dielectric constant.When the amount of graphite nanosheets epoxy resin 3.2 wt%,the pencil hardness of the coating was 3 H and the adhesion was level 3;Compared with the unmodified graphite nanosheets coating,modified graphite nanosheet/epoxy coating had better antiseptic property.