Preparation Of Nano Composites Based On Two-dimensional Layered Structure Materials And Its Application In Corrosion Protection

Metal corrosion has caused huge economic losses,according to the report from National Association of Corrosion Engineers?NACE?,in 2016,the cost of global metal corrosion exceeded$2.5 trillion.Therefore,the protection of metals has attracted the attention of governments.At present,metal protection measures mainly use surface treatment technologies such as oxidation,electroplating,and coating.Among them,coatings are the most widely used.However,the use of a single coating has a limited life span,and corrosion of the corrosive medium in the marine environment for a long time may cause cracks,holes,and delamination of the coating.Recent research shows that adding nanocomposite fillers can improve coating performance.Especially,the two-dimensional material nano material as a filler has a useful application prospect.Unfortunately,two-dimensional materials require agglomeration problems due to their large specific surface area and low surface energy,so surface modification is required before application.In this paper,three modified polymer coatings were prepared as two-dimensional materials of graphene and molybdenum disulfide as anti-corrosion fillers.The anti-corrosion mechanism of different coatings was analyzed and the protective effect was investigated.The specific research is as follows:?1?In this experiment,a nanocomposite of ionic liquid and reduced graphene oxide?RGO-IL?was prepared by non-covalent method,which was used to improve the corrosion resistance of epoxy resin?ER?.The morphology and functional groups of RGO-IL were characterized by scanning electron microscopy?SEM?and fourier transform infrared spectroscopy.Its coating properties were tested by electrochemical experiments and simulated ocean immersion experiments.The interfacial wettability of RGO-IL/ER is characterized by static contact angles.The SEM showed that the surface of the RGO-IL composite was a pleated sheet structure and uniformly distributed with circular spots,indicating that the hydrophobic IL was effectively adsorbed on the surface of the graphene.The results of the contact angle test showed that the ER coating containing RGO-IL exhibited better hydrophobicity than the pure epoxy resin coating.Electrochemical corrosion protection tests have also shown that the corrosion resistance of the coating is significantly enhanced.The corrosion resistance of different coatings was compared by immersion test.The results show that the composite coating containing RGO-IL has the best protection performance after 120 h immersion,which shows that the inhibition of the ionic liquid and the barrier action of graphene are well combined to produce a graphene-based coating with excellent corrosion protection.?2?A material with superhydrophobic properties is obtained by constructing a micro-nano two-layer structure of the material and combining low surface energy materials,according to the design principle of this superhydrophobic material.A 3D graphene oxide composite was prepared and applied to a polydimethylsiloxane coating?CGO@SiO₂-FAS/PDMS?.The coating can be applied to metal surfaces using a variety of conventional coating methods such as spraying,brushing and dip coating.The prepared materials were characterized by scanning scanning electron microscopy and Fourier transform infrared spectroscopy and thermogravimetric analysis.Through optimization experiments,it was found that the optimum addition amount of CGO@SiO₂-FAS in the PDMS coating was 4 wt%.Contact angle test showed that PDMS coating containing with 4 wt%CGO@SiO₂-FAS has the best hydrophobicity,the static contact angle was 128°and the sliding angle was 20°.The corrosion resistance of different coatings was compared by electrochemical test.Compared with pure PDMS,the coating containing 4 wt%CGO@SiO₂-FAS showed excellent corrosion resistance and the corrosion inhibition efficiency was 99.3%,which shows that the hydrophobic performan of the coating has a good protective effect on the metal.?3?AnanocompositeofchitosanmodifiedMoS₂andaniline trimer?MoS₂@CS-CAT?was prepared.The composite has good dispersibility in epoxy coatings.It was observed by scanning electron microscopy that fibrous nano-CAT covered the surface of MoS_2.The results of the contact angle indicated that the MoS₂@CS-CAT coating is hydrophobic,which enhances the barrier effect of the coating on water molecules.The results of polarization curves showed that the MoS₂@CS-CAT/ER composite coating has a higher corrosion potential?0.112 V?than the MoS₂/ER coating,and its corrosion inhibition efficiency can reach 99.6%,which indicates that The composite coating has excellent corrosion protection.