Synthesis Of The New Kinds Of Phosphate Pigments And Their Application In Coatings

The most common effective rust prevention method for metal substrates such as steel is to apply an organic or inorganic coating on the surface of the metal substrate,in order to achieve corrosion prevention by physical or chemical methods.Compared with traditional lead-based and chromium-based anti-rust pigments,phosphate-based pigments have the characteristics like non-toxic environmental protection,low price and great corrosion resistance and so on,so they occupy an important position in the greening development of coatings in China.In this paper,three new phosphates were prepared:nanoerystalline zinc phosphate,phosphate-molybdate composite material,inorganic phosphate-organic corrosion inhibitor bonded anti-rust pigments,and explored their anti-rust properties.The main research work and conclusions as follows:?1?ZnO and H₃PO₄ were used as raw materials,added different concentrations surfactants,adding surfactant,and synthesizing nano-sized zinc phosphate by grinding and adding surfactants.The optimum process conditions were discussed by single factor conditions.The product was characterized by DLS,SEM,XRD and FT-IR.It was applied in epoxy coatings and was applied to the surface of iron sheets to observe it's coverage,detected the anti-rust ability by the salt spray test.The results showed that when the reaction conditions were the concentration of surfactant CTAB is 9×10^-4mol·L^-1,the grinding time is 3h,the grinding medium is the zirconium sphere,the ratio of ball to material in the grinding tank was 150:1,and the ratio of grinding balls is?10mm:?6mm=1:4,the rotation speed is 200r·min-1,the solid-liquid ratio is 1:1,the average particle size is 68 nm,the granular nano-sized zinc phosphate can be synthesized and the process can be controlled.The salt spray test shows that the average salt spray resistance time of the nano-sized zinc phosphate coating by salt spray test is 546 h,compared with 384 h of red lead,144h of commercial zinc phosphate and other phosphate material is longer,which further proves that the prepared nano-sized zinc phosphate has excellent corrosion resistance.Through the surface observation of the coating,the surface of the nano-sized zinc phosphate coating is smooth and compact,and has good physical shielding rust resistance;The nano-sized zinc phosphate particles are fine and even distribution,and the particle's size distribution is narrow,have good dispersion in coatings,the storage is stable,and in the coating layer the aperture can be reduced,so that the coating is exquisite and dense,and the intrusion of corrosive substances are more effectively prevented,so physical shielding performance is enhanced on the basis of chemical rust prevention.?2?The zinc-iron phosphate-molybdate composite phosphate material was prepared by cations of Zn²⁺,Fe³⁺,and anions of PO₄^3-,MoO₄^2-.The effects of PO₄^3-/MoO₄^2-molar ratio,Fe³⁺/Zn²⁺molar ratio,reaction pH value,reaction temperature and reaction time on the content of phosphate and molybdate in the product were investigated by complete randomalized design.The content of phosphate and molybdate were used as the double-indicator responses,and reaction conditions were optimized by the central composite design response surface.The products were characterized by SEM?XRD and FT-IR,and applied to epoxy coatings for salt spray test to determine its anti-rust properties,and analyzed its mechanism.The results show that the order of influence of different factors on the content of phosphate and molybdate is:cation mole ratio>pH>temperature>time,the mole ratio of phosphate to molybdate is5:1,iron-zinc ion mole ratio is 0.98:1,the pH is 6,the temperature is 78°C and the time is 79min,the phosphate and molybdate can reach 34.79%and 5.15%respectively.The composite product was subjected to salt spray test,and the salt spray resistance time was close to red lead,which was 10%and 200%respectively higher than imported similar products and commercial zinc phosphate.Due to the synergistic effect of ions,the synthesized composite phosphate has superior corrosion resistance.?3?The aluminum tripolyphosphate was used as host lattices,organic amine corrosion inhibitor:ethanolamine,rosin amine,aniline as the guest molecules,and using hydrothemalsynthesis,ultrasonic methods to intercalate and strip the aluminum tripolyphosphate,the aniline of intercalated aniline-aluminum tripolyphosphate is oxidized to polyaniline-aluminum tripolyphosphate,and characterized the product by XRD,SEM and FT-IR,analyzed the mechanism of intercalation reaction,and the explored synthesis of inorganic-organic chemical bonding anti-rust pigment is.The results show when the reaction temperature is 150°C,and the time is 2h,ATP:triethanolamine=1:1.2?m/m,the same below?,ATP in solvothermal method can be intercalated and stripped by ethanolamine.The preferred intercalation ratio of aniline is ATP:aniline=1:0.5,for solvothermal reaction the temperature is 100°C,and the time is 2h;for the ultrasonic reaction,the time is 6h,the temperature is 60°C,and in both methods ATP can be intercalated and stripped by aniline.The inorganic-organic composite polyaniline-aluminum tripolyphosphate whose polyaniline oxidized by aniline is still retains the flaky morphology.However,rosin amine cannot intercalate with aluminum tripolyphosphate.