Research On Preparation And Performance Of Low Surface Heat Resistant And Anticorrosive Clay

The interior of the ship’s equipment base,piping system flange and other parts had a special-shaped structure.Because of the complex shape,which had many gaps,edges and corners,and the uneven surface,the pre-treatment construction was difficult to continue.Besides,the equipment was strongly affected by salt and humidity,and corrosion had a fast development on the sea.Covered with an insulating material,this kind of material was likely to cause condensate to accumulate on the outer wall of the coated pipeline,resulting in corrosion of the pipeline,flange,and valve,which led to pipeline leakage or flange fasteners and valves cannot be opened.Therefore,it was urgent to develop a new multifunctional integrated filling and coating material suitable for special-shaped structural parts,which could meet the 15-year service life in the temperature range of 100-150°C.This paper prepared low surface treatment composite heat-resistant anti-corrosion cement which was used for long-term anti-corrosion in special parts and harsh environments.By adding rust conversion agent and other additives to improve its low surface treatment performance,its rust conversion,water conversion mechanism and anti-corrosion performance were discussed with capability to construct under rust and water conditions.Formation mechanism and water conversion of water-in-water emulsion.What’s more,the water absorption phase change of illite powder and the formation mechanism of water-in-oil emulsion and water conversion were studied.Through the best composition and preparation process of anti-corrosion cement suitable for low surface treatment experiments,the effect of illite powder and its modification treatment on the salt spray resistance and UV aging resistance of the coating were studied.As a natural mineral,illite powder can absorb Na⁺on the surface of the substrate and effectively inhibit the transfer of Cl^-due to its special composition and flaky structure,forming an effective barrier layer in the coating,inhibiting corrosion media and reflecting ultraviolet light To improve the salt spray resistance and anti-aging performance of the coating.In the experiment,the neutral salt spray test of the original illite powder coating reached118-142h,and had good anticorrosive property,but the coating has low gloss and the anti-aging performance is not High,the initial gloss of the coating is only 73.1%,and the loss of light after 72hQUV is about 83.13%.Infrared spectrum and XRD show that the silane coupling agent N-（β-aminoethyl）-γ-aminopropyltrimethoxysilane（KH792）Modification of illite powder,-OH in the polysiloxane structure produced by hydrolysis of KH792 and-OH in the structure of illite powder are combined through chemical bonding and adsorption,and coated on the surface of the flake powder to reduce the Yili At the same time as the surface energy of the stone powder,active groups such as-NH ₂ and-OH are introduced,which has better compatibility and reactivity with the coating organic polymer,and exhibits excellent anti-corrosion and anti-aging properties.The results show that the powder surface modification treatment conditions are different,and the properties of illite powder are different.After one hour of modification,illite powder has better compatibility and corrosion resistance,the salt spray resistance of the coating is better for up to 200h,the modification treatment is more than 3h,and the hydrolysate silica self-polymerization compound is adsorbed on the surface of the illite powder It can strengthen the interface effect to a certain extent,have a certain hot electron capture ability,and significantly improve the anti-aging performance of the coating.After 72hQUV,the gloss loss is about 36.66%,and the color difference is only0.774.Analysis of composition,structure and electrochemical impedance spectroscopy before and after rust transformation on steel substrate,the rust conversion effect,mechanism and synergistic mechanism of aluminum tripolyphosphate,HEDP and tannic acid were studied to optimize the optimal composition.There are five very active-O-,with strong ion trapping ability,which can form a chelate with metal ions,which effectively prevents the electrolyte from infiltrating.The electrochemical impedance test shows that as the immersion time increases,aluminum tripolyphosphate will further It decomposes into orthophosphate and improves the corrosion resistance of the substrate.Within six hours,as the immersion time increases,the resistance value of the conversion film increases,and the maximum resistance of the conversion film layer is 954.4Ωcm ²,indicating that the speed of rust conversion to form a protective film Slow,the corrosion resistance of the conversion film is low,and it has a certain post-corrosion resistance.Aluminum tripolyphosphate is compounded with HEDP and tannic acid,all of which have chelation,HEDP can form a six-coordinate octahedron with Fe ³⁺Chelates,with methyl groups attached to the structure,provide more electron-donating groups,making the adjacent C atoms more negatively charged and stronger in binding to Fe ³⁺;tannic acid has an ortho-OH group,can chelate with metal ions to form a highly cross-linked carboxylic acid Network,isolate the corrosive medium to improve the anti-corrosion period effect.The three together form a composite conversion film on the surface of the rusted substrate through a synergistic effect,the impedance value reaches 32495Ωcm ²,the rust conversion ability and the corrosion resistance of the film layer are significantly improved.Spectroscopy,X-ray diffractometer,X-ray photoelectron spectroscopy,and scanning electron microscopy prove that when the three are combined,the organic acid is adsorbed on the aluminum tripolyphosphate particles through physical and chemical adsorption,and the electrostatic repulsion can prevent the tripolyphosphate ions from forming agglomeration.Phenomenon,make it evenly dispersed,improve the binding force of the coating film,have better corrosion resistance and rust conversion ability.In the oily system with lithium-based grease as the basic system,orthogonal optimization is carried out with electrochemical impedance values,compound rust The best composition of the conversion agent is:8%aluminum tripolyphosphate,16%HEDP,9%tannic acid.Experiments have shown that the rust conversion mechanism is the same under oily/watery conditions,the rust conversion rate is slow under oily conditions,and the permeability is poor.Under the condition of carrying water,the anticorrosion material and the substrate have poor binding force,and the presence of water accelerates the corrosion of the substrate.In this paper,the substrate is realized by physical and chemical effects of illite powder phase change water absorption,water-in-oil emulsion system formation and silane coupling agent hydrolysis Surface water conversion.The structure and water absorption of illite powder before and after modification were studied by thermogravimetric analysis.The results show that illite’s own crystal water is reversible.After heating at 550℃,the crystal water can be absorbed to absorb3.59%of the total mass of free water It is converted into crystalline water.After the kh792modified illite powder is hydrolyzed and the hydroxyl group on the surface of the illite powder is coated on the particle surface to form a barrier layer,the water absorption becomes 1.65%of the total mass.By observing the stability of the emulsion formation Time and droplet morphology,the composition of the composite emulsifier and the formation conditions of the water-in-oil emulsion were studied.The results showed that Span 80 and Span 20 were mixed by 8/2 to form a composite emulsifier,the HLB value was 5.9-6.02,and the oil-water ratio When it is 60:40,the emulsion formed at 20-50℃has a uniform distribution and a small radius.The emulsifier molecules on the interface film are relatively dense and uniform,with high strength and good stability.The addition of can improve the permeability of the rust conversion agent and absorb water through hydrolysis.The silane coupling agent KH858absorbs water and hydrolyzes to form a cross-linked polysiloxane chain,which can further improve the corrosion resistance of the coating.Through the salt spray test,anti-aging test and electrochemical impedance test,the composition and action mechanism of the anti-corrosion cement were studied,and the effects of the type of lithium-based grease,coating thickness,rust conversion agent content,and modified illite powder on the performance of the anti-corrosion cement were investigated.The results show that when heat-resistant lithium-based grease is used to prepare anti-corrosion cement,when the content of rust conversion agent is 23.07%,the QUV test is 500h and the salt spray test is 2000h.The surface of the anti-corrosion cement has yellowing,shrinkage,and mold spots,but there is no inside the coating.There is no corrosion on the substrate.The electrochemical impedance spectroscopy shows that a conversion film is formed on the surface of the substrate,which further improves the corrosion resistance of the cement coating.The cement has good strength,stain resistance and corrosion resistance.