Study On Properties Of Nano-alumina Decorated Hexagonal Boron Nitride Modified Epoxy Coating

Metal corrosion causes serious harm to the lives and environment of contemporary people.Among various anti-corrosion technologies,coating protection is the simplest and most effective method.Epoxy resin?EP?coatings are widely used in the field of corrosion protection due to their chemical resistance,high electrical insulation,low cure shrinkage and high tensile strength.However,due to the large porosity and high crosslink density of the cured epoxy coating,the corrosion resistance period of the coating is relatively short and brittle.Adding functional nano fillers to epoxy resin coatings is one of the effective ways to enhance the performance of all aspects of coatings.In this paper,hexagonal boron nitride?h-BN?and nano-alumina?nano-Al₂O₃?are used as raw materials.After the two are modified separately,nano-Al₂O₃ is modified on the h-BN surface of the two-dimensional sheet structure to obtain a composite material?PDA-BN@f-Al₂O₃?,the corrosion resistance and mechanical properties of epoxy composite coatings have been significantly improved prepared by adding PDA-BN@f-Al₂O₃ as a filler to epoxy resin.The specific research contents of this paper are as follows:?1?Preparation and characterization of PDA-BN@f-Al₂O₃ composite material.The PDA-BN@f-Al₂O₃ composite material was prepared by chemically modifying h-BN and Al₂O₃ separately,and grafting the modified nano-Al₂O₃ onto the surface of the h-BN sheet.The experimental results show that the PDA-BN@f-Al₂O₃ composite is more uniformly and stably dispersed in water and organic solvents.In addition,the agglomeration of Al₂O₃ modified by silane coupling agent KH550 has been greatly improved.The modified h-BN was successfully stripped into a few-layer sheet structure,and nano-Al₂O₃ in the PDA-BN@f-Al₂O₃ composite material particles are grafted on the h-BN surface,and the grafting rate is about 8%.When m PDA-BN:mf-Al₂O₃=3:1,the Al₂O₃ in the PDA-BN@f-Al₂O₃ composite are more evenly distributed..?2?Research on corrosion inhibition performance of PDA-BN@f-Al₂O₃composite material.The Al₂O₃,BN and PDA-BN@f-Al₂O₃ composite materials were dispersed in 3.5%Na Cl solution to prepare an"extraction solution",and then the steel sheet without the coating was soaked in the"extraction solution".The results show that the Rct and C values of the steel substrate in the PDA-BN@f-Al₂O₃ composite extract are 7.05 and 0.18 compared to the pure saline solution,respectively,indicating that the PDA-BN@f-Al₂O₃ composite can be effective to reduce the corrosion effect of the corrosion medium on the steel substrate..?3?Study on the performance of PDA-BN@f-Al₂O₃ composite modified epoxy coating.Epoxy composite coatings were prepared by using PDA-BN@f-Al₂O₃composite materials as fillers.The test results show that PDA-BN@f-Al₂O₃ composite materials can significantly improve the barrier performance and corrosion resistance of epoxy coatings and the best ratio of fillers is 3:1.After immersion in saline solution for5 days,the impedance value of PDA-BN@f-Al₂O₃?3:1?/epoxy composite coating is 3orders of magnitude higher than that of pure epoxy coating.At the same time,the adhesion,flexibility and wear resistance is also improved.