Preparation And Performance Study Of Microvessel-shaped Pipe Network And Embedded Microsphere Self-healing Coating

Self-healing coatings can heal and repair defects and damage such as microcracks,thereby increasing the reliability of the coating and extending its service life.However,since the development of self-healing coatings,some achievements have been obtained,but further research and exploration are needed.For this reason,this paper studies the preparation process,corrosion resistance and self-healing properties of micro veined pipe network and embedded microsphere self-healing coatings to promote the development and application of self-healing coatings.Pretreatment of the metal substrate is required before the coating is applied.Therefore,the sodium metavanadate solution is study as the pretreatment liquid for the Q235 steel surface.Through the single factor test and the orthogonal experiment,the corrosion rate is taken as the evaluation index to determine the best pretreatment treatment process:NaVO3 pretreatment solution concentration of 55g/L,soaking treatment time is 40min,NaVO3 pretreatment solution pH of 7.6,immersion treatment sample temperature of 40?.Under the condition of this process,the corrosion rate of Q235 steel is 0.1325mm/a,corrosion resistance of Q235 steel is improved.Through the layer assembly method,a micro-vein network self-healing coating has been successfully developed:The structure of the coating is a sandwich structure.Electrochemical impedance spectroscopy analysis and polarization curve analysis show that,compared with the epoxy resin varnish,corrosion inhibitor tung oil(Oil)and cotton cellulose fiber(CNF)combination suitable amount of CNF1%-Oil2%,after immersion corrosion 168h at 35 ?,3.5wt%NaCl solution,the coating resistance value of 104.18.the coating system self-healing mechanism of this type of coating was analyzed by Scanning Electron Microscope(SEM)and Energy Dispersive Spectrdmeter(EDS).CNF was used as the carrier and transport channel of Oil.When the coating was damaged,Oil migrated to the damage site and formed a protective film.Making the coating has good self-healing properties.A self-healing microsphere self-healing coating was successfully fabricated by the layer-by-layer assembly method.Firstly,the hydrothermal synthesis of zinc oxide was carried out.The XRD and SEM tests showed that the hexagonal wurtzite ZnO microspheres with high crystallinity were successfully synthesized,the surface of the microspheres was a honeycomb surface.The laser particle size analysis showed that the average diameter of the synthesized zinc oxide spheres was 5.65?m.The thermo gravimetric analysis showed that the amount of the benzotriazole as a corrosion inhibitor supported on the micronized zinc oxide was 32.35%.After the sample was soaked in 3.5wt%NaCl solution at 35 ? for 168h,the results of electrochemical impedance spectroscopy and polarization curves showed that the corrosion resistance of the samples doped with BTA ZnO microspheres was great,The coating impedance is 103.8 at this moment.SEM analysis and EDS analysis show that the corrosion products are loosely accumulated in the defect site to form a non-densified barrier.The developed self-healing microsphere-embedded coating has some self-healing properties.