| Accidents and economic loss caused by metal corrosion are very serious.Traditional resin-based coating systems have the advantages of strong corrosion resistance,excellent volume stability,environmental friendliness,and easy operation.However,there are also such obvious shortcoming as low mechanical strength and poor aging resistance.Graphene is a two-dimensional carbon nanomaterial with hexagonal honeycomb lattice composed of carbon atoms with sp2 hybrid orbits.Due to its unique layered structure and outstanding performance,well-dispersed graphene must be practicable to improve the working properties of resin-based coating.We need to find a high-performance anti-corrosive coating that is simple,convenient and cost-effective and its preparation method.This article refers to the conventional coating process of the surface of the metal substrate.Through the introduction of graphene,a high-performance,long-life,corrosion-resistant graphene-modified composite coating was obtained.In this work,GNSs were evenly dispersed into alcohol and toluene,respectively,which were in turn sprayed onto certain metal substrate for the tests of rust resistance through a screening method.The results show that the metal surface covered with graphene film is significantly less rusted than the surface without graphene coating,suggesting the effect of strong barrier due to the existence of graphene film on metal surface.On the base of quantitative comparison of the anti-corrosion ability of different standard materials,the rust resistance of different metals must be classified by the order of: aluminum> copper> brass> cast steel.In this paper,graphene is used as the fundamental filler to prepare graphene-modified epoxy resin coatings by a method of dip coating.The amount of graphene is used as the main variable to optimize the structure and performance of composited coating,including hardness,salt spray test,acid vapor test,acid resistance test,other quantitative test and SEM characterization.The experimental results show that the corrosion resistance of composited coatings with the appropriate amount of graphene(graphene content of 0.4% to 0.6%)is significantly better than that of pure resin.The reason is that graphene particles improve the defects on the surface of epoxy resin coatings to improve the corrosion resistance.However,if an excessive amount of graphene is added,for example,0.8% or 1%,the graphene could not be evenly dispersed,which will lead to air bubbles and voids on the coating surface to reduce the corrosion resistance of the composited coating.In this research,graphene was also mixed with polyacrylic acid(PAA)resin to obtain protective coating by making use of toluene as the solvent.The ratio of toluene-to-resin,the amount of graphene were employed as the main variable to prepare the graphene-modified PAA coating for the measurements of mechanical properties,salt spray test,acid vapor test,acid resistance test and other quantitative tests and SEM characterization.The experimental results show that when the ratio of toluene to polyacrylic resin is 4: 1 and the graphene content is 0.6%,the composite coating has the best anticorrosive effect.The reason for analysis is that graphene particles can be dispersed in a polypropylene resin / toluene mixed system,and then a dense composite anticorrosive coating is obtained by evaporation of the toluene solvent.Toluene is used as a diluent to improve the film-forming performance of coating materials,which is beneficial to improve the coating quality and reduce the difficulty of film-forming.As the amount of graphene increases,the anti-corrosion effect of the composite coating becomes better.However,if it is added in excess,it will cause the resin coating layer formed on the surface of the graphene particles to become thin or discontinuous,destroying the three-dimensional network of the resin matrix.The structure causes the voids of the composite coating to become larger,but will intensify the invasion of the corrosive medium. |
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