| Waterborne inorganic anticorrosive coating has excellent anti-corrosion resistance,excellent adhesion,good solvent resistance,weatherability,high hardness and strong self-repair ability.It has been widely used in the offshore platform,such as marine anticorrosive steel pile wharf,submarine pipeline,tunnel and other offshore steel structure and the industrial field.Flake zinc powder has been paid more attention because of its advantages such as strong floating ability,covering ability and shielding effect,but there are a lot of problems in the use of flake zinc powder in waterborne inorganic zinc rich coatings,such as poor dispersion,easy to settle,poor mechanical properties and poor storage stability,which affect the corrosion resistance and mechanical properties of the coating.In addition,the production cost of flake zinc powder is high,which limits the application of flake zinc powder in the aqueous inorganic zinc rich coating to a certain extent.Therefore,it is an urgent problem to study the better performance of waterborne zinc rich anti-corrosive coatings.Aiming at the above problems,the influence of adding silicone acrylic emulsion to potassium silicate based material was studied,and also the influence of adding easy dispersion and low cost to the spherical zinc flake zinc powder was discussed,and the effects of kinds of modifiers of zinc flake on coatings was explored in this paper,which provide technical and theoretical guidance for marine anti-corrosion engineering.In this paper,a kind of high modulus modified potassium silicate material was prepared by using water,potassium hydroxide and silica sol as the main material and silicone acrylic emulsion as modifier,and then mixed with zinc powder preparation of modified potassium silicate waterborne inorganic zinc rich coatings.To investigate the effect of the modulus of potassium silicate solution,the reaction temperature,reaction time and the addition of silicone acrylic emulsion on the stability and performance of the coatings.The optimum preparation conditions were determined by orthogonal test:The modulus of potassium silicate was 5.5,while the reaction temperature was 50?,and the silicone acrylic emulsion was added by 25%.The results showed that the organic groups in the modified potassium silicate were connected to the framework of silicate.In addition,a certain proportion of spherical zinc powder was added to the flake zinc powder to prepare the coating with excellent corrosion resistance and mechanical properties.After immersion of 288h in the 3.5%NaCl solution,the corrosion potential of the coating with the addition of 10%spherical zinc powder was-1.07 V higher than that of-0.99 V without adding spherical zinc powder coating.When the sample was immersed in pH=4 HCl solution,the average weight loss rate of 1.262%with adding 10%zinc powder coating was reduced by 0.07%compared with that of 1.332%without adding spherical zinc powder coating.The best ratio of flake zinc and spherical zinc powder is 4:1.The silane coupling agent KH560 and six sodium hexametaphosphate two modifier on flake zinc powder was modified by activateddegree test modified zinc powder,anti sedimentation volume,mechanical properties of the coatings,the corrosion resistance,and the optimum modifier for silane coupling agent KH560.and the KH560 powder reaches the maximum value of 48.74%when it was added in activated degree sheet of 8%.The settlement volume reaches the minimum value of 0.55 ml g-1,and the modified coating corrosion potential of-0.95 V was-1.07 V higher than that of the unmodified coating in 3.5%NaCl solution after soaking 288 h.Compared with unmodified coatings of average weight loss rate of 1.332%,the modified coating in pH=4 HCl of average weight loss rate of 1.288%reduced 0.044%after solution corrosion of 72 h.Finally,it was showed that after the addition of spherical zinc and using of the modifier,clearance in the coating decreases by scanning electron microscopy and energy spectrum test and analysis.The energy spectrum tests showed that the lowering of the Fe content in the coating,which enhanced the corrosion resistance of the coating. |
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