The Study On Cathodic Disbonding Performance Of Different Resin And Curing Agent Of Epoxy Coating

Epoxy coating has excellent anti-corrosion,insulation,adhesion,low shrinkage,temperature resistance and other characteristics,which is suitable for metal protection and corrosion in the marine environment.In the marine environment,using electrochemical protection and anti-corrosion coating protection to protect the coatings.But the cathode protection will reduce the metal and the coating's adhesion,and leading to cathodic disbonding.This paper mainly studies,in seawater tlhrough adding different curing agent(phenolic aldehyde amine,polyamide,alicyclic amine)to epoxy coating's(epoxy E44 coating,epoxy E51 coating,epoxy E44 and E51 blending coating)cathodic disbonding resistance research,and use the open circuit potential and Ac impedance electrochemical test methods to study the electrochemical behavior of the coating.Cathodic disbonding performance of the alicyclic amine epoxy coatings are better than other epoxy coatings,the results of sacrificial anode method is consistent with cathodic protection methods.Distance of cathodic disbonding at-3.5V polarization potential is better than at-1.5V polarization potential.Indicating that-1.5V polarization potential is more suitable for the 9 kinds of coating.9 kinds of coatings immersed in seawater for 182 d reach 108 ?·cm2,which still follows the initial rules of immersion.With the extension of immersed time,the impedance modulus decreased,and the corrosion resistance of 9 kinds of coating decreased gradually.9 kinds of coatings immersed in seawater for 182 d has a good adhesion to the substrate,no traces of corrosion be found.Using energy spectrum analysis and X-ray diffraction analysis,do not find iron chlorides and oxides(Fe3O4?FeO and FeCl2)in the stripping of the surface of the coating and substrate surface.The prediction formula of coating corrosion life is established based on Grey Neural Network.The life prediction of epoxy E44 coating of respectively adding phenolic aldehyde amine,alicyclic amine and polyamide curing agent are 450 d,1135 d and 925 d.Espectively adding phenolic aldehyde amine,alicyclic amine and polyamide curing agent to epoxy E51 coating's life prediction are 555 d,1323 d,1130 d.Espectively adding phenolic aldehyde amine,alicyclic amine and polyamide curing agent to epoxy E44 and E51 blending coating's life prediction are 462 d,1239 d,1004 d.