| In the current,the surface anti-corrosion treatment of metal materials such as steel structures is mainly based on solvent-based anti-corrosion coatings.It is obvious that these oil-based paints not only cause serious pollution,endanger human health,but also destroy large amounts of environmental resources.With the control of volatile organic compounds(VOCs)in coatings,the development of environmentally friendly coatings with low VOCs is one of the most important development directions for the coatings industry.From the perspective of environmental protection,this dissertation develops a two-component water-based composite epoxy anticorrosion coating for steel surface anticorrosion purposely and purposefully.Specifically,the following three aspects are discussed:(1)Grouping experiments were used to optimize the ratio of coating film forming materials.Scanning electron microscope(SEM)and atomic force microscope(AFM)were used to test and analyze the morphology of different coating layers coatings.The results showed that the coating was the most smooth when the ratio was 4:1.The mechanical hardness test showed that the coating hardness reached 3H,the impact resistance reached 50 cm,and the adhesion was 2;the electrochemical Tafel polarization Curves,EIS spectra,neutral salt spray tests,and solution-resistant immersion tests showed that the fully cured coating had lower water absorption and better corrosion resistance,which provided initial evidences that the coating could effectively prevent erosion of the film by the corrosive medium.(2)?-aminopropyltriethylsilane(KH550)was used to modify the nano-ZnO to enhance the dispersion and uniformity in the coating;infrared spectroscopy and powder diffractometers were used to analyze the nano-ZnO powder before and after modification.It was found that KH550 was successfully grafted onto the surface of nano-ZnO,making the compatibility of the modified nano-ZnO and the resin improved.Furthermore,through the description and analysis of the mechanical properties,resistance to liquid media,electrochemical performance and neutral salt spray test,the overall performance of the coating after addition of nano-Zn O was improved.Scanning electron microscope(SEM),atomic force microscope(AFM)were used to analyze the surface morphology of different nano-ZnO coatings.It was found that when the addition amount was 0.3% by weight,the coating surface was smooth,the agglomeration phenomenon was weak,and the dispersion performance was good.(3)The basic formula of water-based coating was obtained by orthogonal experiment,and on this basis,the influence of pigment volume concentration(PVC)on salt spray resistance was explored.It was obtained that A component was composed of 25 to 28 parts of water,40 parts of water-based epoxy emulsion,11 to 13 parts of iron oxide red,5 to 6 parts of talc,5 to 6 parts of barium sulfate,3 to 4 parts of mica powder,5 parts of aluminum tripolyphosphate,0.3 to 0.5 parts of thickener,and wetting 0.1 to 0.2 parts of agent,0.4 parts of antifoaming agent,0.2 part of dispersant,and 0.3 part of nanoZnO;the optimized formula of component B was 10 parts of aqueous epoxy curing agent and 10 parts of water.The coating performance after optimization of the formula satisfied the “JG/T224-2007” anticorrosion coating of steel structures for construction,and the cost was reduced by approximately 5% to 10% compared to ordinary epoxy zinc-rich primers;using test methods such as Tafel polarization curves and AC impedance(EIS),the optimized formula coating was compared with a commercially available solvent-based epoxy anti-corrosive coating.The results indicated that the water-based epoxy coating had relatively better corrosion resistance;in addition,thermal analysis tests were also used to show that the coating had good thermal stability. |
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