| Metal corrosion has caused huge energy waste in natural gas and oil pipelines,chemical production,bridge construction,and other fields,it has caused serious pollution to natural resources such as soil and groundwater,resulting in significant economic losses.Traditional water-based inorganic zinc-rich coatings use silicate aqueous solution as the film forming substrate,and spherical or flake zinc powder as the pigment,anticorrosive coatings prepared by adding some coating additives have advantages such as good corrosion resistance,solvent resistance,weather resistance,and excellent adhesion,it has been widely used in the field of metal corrosion protection,but it has poor dispersion,due to the high content of zinc powder,it is easy to cause sedimentation and agglomeration,which affects the anti-corrosion performance of the coating.In this paper,water,potassium hydroxide and silica sol are used as main raw materials,and silicone acrylic lotion is used as modifier,a modified high modulus potassium silicate solution was prepared,and then corrosion inhibitors were loaded onto the interlayer structure of hydrotalcite on the surface of flake zinc powder,LDH-Mo flake zinc powder was synthesized as a pigment,and a inorganic silicate zinc-rich coating with inhibitor was prepared by mixing the pigment with a silicate base material.Molybdenum ions loaded with hydrotalcite on the surface of zinc powder are released when they contact the corrosion medium,which has a good corrosion inhibition and protection effect on the coating defects and the substrate,it can improve the barrier performance and corrosion resistance of the coating.The corrosion inhibitor molybdate ion is an environmentally friendly inorganic corrosion inhibitor with the advantages of environmental friendliness and high corrosion inhibition efficiency,it can be widely used in fields such as sea crossing bridges,natural gas and oil pipelines.The main research contents of the paper include:(1)The preparation process of modified high modulus potassium silicate solution was studied.The effects of potassium silicate solution modulus,stirring time,reaction temperature and the addition amount of silicone acrylic lotion on the storage stability,solution state and coating performance of high modulus potassium silicate base materials were analyzed through single factor experiments,the optimum parameters for preparing modified high modulus potassium silicate solution were obtained: modulus 5.5,stirring time 15 min,temperature 50℃,and addition amount of silicone acrylic lotion 25%.(2)Molybdate intercalated zinc aluminum hydrotalcite(LDH Mo flake zinc powder)was synthesized on the surface of flake zinc powder by hydrothermal synthesis and ion exchange methods,the structure of modified flake zinc powder was characterized by X-ray diffraction(XRD)and infrared spectroscopy(FT-IR),the corrosion inhibition mechanism of LDH Mo flake zinc powder was studied using UV VIS,the release rule of Mo O42-and the ion exchange between Mo O42-and Cl-in solution were tested.The results showed that,the release amount of Mo O42-tends to stabilize with time,and Cl-in the solution enters the interlayer structure of hydrotalcite on the surface of zinc powder through ion exchange.(3)Finally,in order to evenly disperse LDH-Mo flake zinc powder in the base material and reduce its agglomeration and sedimentation in potassium silicate solution,select Compress zinc oxide powder and combine it with KH560 and sodium hydroxyaminophosphate,by testing the activity and sedimentation volume of modified zinc powder,it was determined that when the addition amount of modifier KH560 was 8%,the dispersibility and anti settling ability of LDH-Mo flake zinc powder are the best.The effect of different content of modified LDH Mo flake zinc powder on the performance of the coating was studied.Coatings with a mass ratio of pigment to substrate of 20%,30%,40%,and 50% were prepared,through experimental methods such as salt water resistance time,adhesion,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),electrochemical impedance spectroscopy(EIS),and potentiodynamic polarization curve testing,the physical properties,comprehensiveness,and corrosion resistance of each coating were compared and analyzed.The results show that when the mass ratio of pigment to base material is 40%,the coating prepared has better film formation,denser coating,and better adhesion and corrosion resistance. |
