Study On Protective Effect And Mechanism Of Modified Silane Coating On Reinforced In Cement-based Material

In the Marine environment with high salt content,steel corrosion is the main reason to reduce the durability of reinforced concrete structures.Therefore,it is a necessary measure to protect the structure from chloride attack by directly coating the surface of steel bar with organic anticorrosive coating.So this article with ethyl orthosilicate(TEOS)and isobutyl triethoxy silane(IBTS)as the foundation,add graphene oxide(GO)and cerium nitrate anti-corrosion material,preparation of coating corrosion resistance of the modified silane,through microscopic characterization and electrochemical testing technology research such as anticorrosive effect and mechanism of the coating,is committed to develop green and efficient corrosion resistant coating.The main results are as follows:(1)The study on the GO modified silane coating found that the covalent bond between the added GO and the silane hydrolyzed silanol occurs,which reduces the porosity of the silane coating.However,high concentration of silicon alcohols cannot be stable and tend to cross-link with each other,making the coating uneven distribution and reducing the corrosion resistance of the coating.The maximum anticorrosion efficiency of GO modified silane coating is 99.36%.The study on the anticorrosion mechanism of GO modified silane coating shows that GO evenly distributed in the silane coating acts as a stable physical barrier,reducing the area of reaction between electrolyte and silane,greatly slowing down the degradation of the silane coating,improving the stability of the coating,and thus delaying the corrosion process.(2)The study of cerium nitrate modified silane coating with different concentrations of cerium nitrate found that cerium nitrate did not react with silane,but only physically adsorb in the silane coating,but cerium nitrate would promote the agglomeration of silanol,and excessive cerium nitrate would reduce the uniformity of the coating and the corrosion resistance of the coating.The modified coating containing5g/L cerium nitrate has the best anticorrosion effect,and the maximum anticorrosion efficiency is 99.46%.The addition of cerium nitrate gives the active anticorrosion ability to the Ce salt modified silane coating.When the electrolyte diffuses to the coating/metal interface,Ce(Ⅲ)generates electrochemical corrosion and oxidizes to form Ce(Ⅳ),which protects the steel bar from corrosion.The obtained insoluble cerium oxide reduces the porosity of the coating,which makes Ce modified silane coating have long-term and stable corrosion resistance.(3)It is found that the failure of reinforced mortar samples coated with different coatings goes through three stages through accelerated corrosion test of salt solution drying and wetting cycle.The first stage: passivation stage,electrolyte in this stage needs to overcome the huge pore resistance of mortar to diffuse to the coating surface,the coating structure remains intact.The second stage: corrosion initiation stage,electrolyte after early diffusion,connecting the coating and the external solution,causing local interface corrosion,coating attack,at this time,the coating play its anticorrosion role,reduce or prevent the corrosion of steel.The third stage: coating failure stage,after the evolution of the second stage,there is a large area of corrosion,a large number of corrosion products gathered at the interface,the coating irreparable damage,serious corrosion of steel bar.