The Research And Development Of Electric Double-layer Waterborne Inorganic Coatings

In recent decades,the coatings is consider to be the most effective technique for corrosion protection.The water-borne inorganic zinc-rich coating has been obviously used because it is cost effective,earth crust,non-toxic,ecofriendly materials.The electrochemical effectiveness of coatings,required high content of the globular zinc powder.As it has large quantity of zinc dust that was produced during its production,which causes various cracks and serious defects in the coating.Hence made the globular zinc powder unable for even dispersion and ultimately reduced its anti corrosion capability.There are two main factors of corrosion.One is non-charged medium such as(O2)and water H2O,while other is charged species like(H+ and Cl-).Therefore to protect the substrate surface from corrosion these factors must be controlled.Here we have designed a strategies to enhance the effectiveness of zinc-rich coating by adding the lamellate materials(sericite)in Zn-rich coating by physical method,or added(MMT)to build a double layer on the surface,which diminished or minimize the reaction of H2O and O2 on the substrate surface,also the double layers repel the dielectric charges(H+,Cl-)hence increase its resistant to corrosion.The present investigation included:(1)Preparation of base material.The sodium silicate was used as raw |materials for Zn-rich coating but it has very low modulus(3.3)which is not effective for coating.Therefore silica solution was added to the sodium silicate improve the modulus of sodium silicate.In this reaction the amount of silica,temperature,types and amount of silane coupling agent have great influence on the modulus of sodium silicate solution.The sealing method of observation,grain size tests and FTIR determined the optimum conditions such as temperature(50?)and KH560(3%)for the preparation of high modulus sodium silicate upto 4.(2).Preparation of Electric double layer nanofillers.Electric double layer nanomaterials was prepared by ultrasonication,and characterized by XRD,SEM,HRTEM,FTIR,AFM and BET.The outcomes indicated that compared with the original montmorion,the electric double layer nanometer materials formation with single flake structure of a larger specific surface area from 59 m2/g to 62 m2/g,and the average thickness decreases from 5 nm to 1 nm.(3).The diverse quantities of the sericite and electric double layer nano materials was added to the zinc-rich coating because the sericite and electric double layer nanomaterial contents tremendously effect the properties of the Zn-rich coating.The performance of modified Zin-rich coating was tested by water resistance salt spray test,SEM and electrochemical measurements.The results of various measurements exhibited the sericite(10%)and electric double layer nanomaterials(3%)accounted best,the salt spray resistance of the prepared coating can be as long as 550h.Compared with the zinc-riched coating,the corrosion potential increases by 19.35%,the current density decreases by 87.41%,and the corrosion resistance is obviously improved.