Study On Corrosion Resistance Of Graphene/Epoxy Resin Coating And Construction Of Heavy-duty Anticorrosive Coating

Waterborne organic coatings have emerged as an important research trend in the field of metal anti-corrosion because of its easy operation,superior protective effect and environmental friendly nature.Since graphene has excellent physical and chemical properties,it can overcomme the shortcomings of Waterborne coatings,thereby giving rise to more effective anti-corrosion coating.In this study,epoxy resin-based composite coating was prepared by respectively using polyaniline,polyurethane and halloysite as the fillers,and then graphene was introduced to prepare graphene/epoxy resin-based composite coating.Finally,graphene/epoxy resin-based composite coating was used as the middle layer to build heavy-duty anticorrosive coatings.The microstructure and related properties of the coatings were characterized by basic physical properties,Fourier transform infrared spectroscopy(FT-IR),Tafel polarization curve(Tafel),electrochemical impedance spectroscopy(EIS)and salt spray test(NSS)test.For the epoxy resin-based composite coatings,polyaniline,polyurethane and halloysite can improve the corrosion resistance of pure water-soluble epoxy resin coating(EP).The results show that the anticorrosive property of the composite coating is the best when the contents of polyaniline,polyurethane and halloysite were 1.5 wt.%(PANEP-1.5%),10 wt.%(PUEP-10%)and 0.5 wt.%(HEP-0.5%).At this time,the corrosion potential of the composite coating was increased to some extent compared with EP,the corrosion current was far less than EP,and the charge transfer resistance and impedance amplitude of the composite coating are greater than that of EP,the salt fog time of composite coatings was 40 h,38 h,36 h;For the grapheme/epoxy resin-based composite coatings,When the graphene content was 0.6 wt.%(GEP-0.6%),the graphene/epoxy composite coating has the highest corrosion potential,the lowest corrosion current,the largest charge transfer resistance and impedance of the coating,the salt fog time of GEP-0.6% was 80 h;When graphene content was 0.6 wt.% and polyaniline content was 1.5 wt.%(GPANEP-0.6%),the corrosion potential,the corrosion current and the coating charge transfer resistance and the impedance amplitude of GPANEP-0.6% were less than that of GEP-0.6%,the salt fog time of GPANEP-0.6% was 78 h;When the graphene content was 0.6 wt.% and the content of polyurethane was 10 wt.%(GPUEP-0.6%),the corrosion potential,the charge transfer resistance and the impedance amplitude of GPUEP-0.6% were greater than that of GEP-0.6%,the corrosion current was less than that of GEP-0.6%,the salt fog time of GPUEP-0.6% was 140 h;When the content of graphene was 1.0 wt.% and the content of halloysite was 0.5 wt.%(GHEP-1.0%),the corrosion potential,the corrosion current,the charge transfer resistance and the impedance amplitude of GHEP-1.0% were all greater than that of GEP-0.6%,the salt fog time of GHEP-1.0% was 90 h;For the heavy-duty anticorrosive coatings,the H-GPUEP has larger corrosion potential,the smallest corrosion current,and the largest charge transfer resistance and the impedance amplitude.The salt fog time of H-GPUEP was up to 728 h.