Research On Preparation And Anti-corrosion Performance Of Polyvinyibutyral/Two-dimensional Material Composite Coating

Metal corrosion is one of the main reasons for the failure of marine equipment and heat exchange equipment.The research and development of two-dimensional materials provides a new solution for effectively solving the corrosion problem of metal equipment.2D materials such as graphene and graphene-like materials have a unique layer structure,so they have a barrier effect on corrosive media such as oxygen and water.However,graphene,as a material with excellent electrical conductivity,has strong "corrosion promotion activity".When the coating is damaged,it is easy to form"micro-galvanic corrosion" like galvanic reaction with the metal substrate.This reaction accelerates corrosion and greatly limits the anti-corrosion applications of graphene.Graphene-like materials also have similar shielding effects,but there is still a lack of research on whether they are prone to "micro-galvanic corrosion".Based on the two types of graphene semiconductor materials,tin sulfide and molybdenum disulfide,this paper studies their corrosion resistance and "corrosion promotion activity",and tries to reduce the occurrence of "micro-galvanic corrosion" through some modification measures.In this paper,a liquid phase exfoliation method was used to prepare and extract two-dimensional SnS and MoS2 nanosheets with 50 nm diameter tin sulfide(SnS)and molybdenum disulfide(MoS2)respectively by ultrasound and centrifugation.Field emission scanning electron microscope(FE-SEM)and transmission electron microscope(TEM)were used to characterize the surface morphology and layer thickness of two-dimensional nanosheets.The results show that the prepared SnS and MoS2 are uniform in size and small in thickness,which meets the requirements of being used as an anti-corrosion coating additive.This paper presents the anti-corrosion application of polyvinylbutyral/tin sulfide(PVB/SnS)composites,where the liquid-phase exfoliated(LPE)SnS nanosheets are uniformly embedded in the PVB matrix.The measurement results of the potentiodynamic polarization,the electrochemical impedance spectroscopy(EIS)and the FE-SEM demonstrate that PVB/SnS composites coatings have the excellent corrosion protection behavior for copper under 3.0%NaCl solution.Besides,we investigated the anti-corrosion performance with different content of SnS nanosheets.The results show that embedding 0.1 wt%SnS nanosheets in PVB matrix can greatly improve the anti-corrosion properties of the coating due to the enhancing "Labyrinth effect" of the coatings.In addition,the results of the molecular dynamic analysis further shows the high interaction energy between PVB/SnS composites and copper.Moreover,the scratch tests reveal that the PVB/SnS composites coatings have the weak corrosion-promotion activity,indicating a promising potential application in the corrosion protection of the metal surface for the ocean engineering.The polyvinylbutyral/molybdenum disulfide(PVB/MoS2)composite material was modified by adding nano-zinc particles.The results of electrochemical experiments and SEM observations show that in a 3%NaCl solution,PVB/MoS2 coating has a good anti-corrosion effect on Cu,and the addition of nano-Zn further enhances this effect.In addition,this paper studied the anti-corrosion performance of MoS2 nanosheets with different contents and found that the coating has the best anti-corrosion performance when 1 wt%MoS2 nanosheets are embedded in the PVB matrix.The corrosion mechanism of MoS2/PVB composite material on copper surface was studied by molecular dynamics(MD)simulation.The results show that the nano-PVB/MoS2 system can be better adsorbed on the copper surface.