Preparation And Performance Of The Wear-resistant And Anti-corrosion Coating With Multi-layer Structure And Surface Texture Coupling Bionic

Corrosion and wear are inseparable,and surface coating technology,as an essential means of metal protection,has a broad application prospect.However,the hard monolayer coating,mainly made of ceramic metal,has poor toughness and is prone to brittle fracture;the elastic monolayer coating,mainly made of polymer,has low hardness and single function,which cannot resist cutting and abrasion and meet the demand of complex and diversified use.Rigid and elastic monolayers are limited in harsh environments and have long-lasting protection.The multilayer structure of shells,the hard and tough mother-of-pearl layer,and the concave and convex surface texture make them show good resistance and buffering ability when subjected to abrasion by sand and fluid.The combination of hardness and toughness is an effective way to improve the abrasion resistance of the coating,and the multilayer structure can provide a good loading platform for functional nanoparticles to realize the multi-functionalization of the coating.Epoxy resin（EP）has high hardness,wear resistance,and strong bonding with metal,but epoxy resin is brittle and easy to fracture after curing,and more pores are produced after solvent evaporation,which is not conducive to ionic corrosion resistance.Fluorocarbon resin（FEVE）has high flexibility,a low coefficient of friction,and many C-F bonds on the surface to provide weathering and corrosion resistance.However,due to the low surface energy,the adhesion of fluorocarbon resin to metal substrates could be worse and prone to spalling and separation.Inspired by the multilayer structure of shells to resist erosion and the non-smooth structure of the shell exterior to resist abrasion and non-infiltration,this paper selects the hard epoxy resin and soft fluorocarbon resin for multi-cycle alternating lamination with enhancing the mechanical properties of the substrate from the structure and surface morphology of the coating substrate.The EP and FEVE were modified with mesoporous Si O₂ and GO containing corrosion inhibitor BTA,respectively.Then the bionic weave morphology was constructed on the surface layer to investigate the effects of interlayer structure,particle modification,and surface weaving on the wear and corrosion resistance of the coating and to analyze the possible mechanism.The main research contents and conclusions of this paper are as follows.Optimize the curing process of fluorocarbon resin by using an organism bismuth catalyst.The optimized addition ratio and the reaction time of crosslinking at room temperature and medium-high temperature were obtained by DSC and rheological tests to shorten the curing time of FEVE.A multi-cycle EP/FEVE soft and hard laminated system coating with the same total thickness was prepared by using epoxy resin as the base and fluorocarbon resin as the surface to form a cycle.When the alternating structure was double-cycled,the coating’s average friction coefficient and wear rate under dry and wet friction were reduced by 12.9%and 72.8%compared to the pure EP hard layer;and 3.2%and 56.6%compared to the pure FEVE soft layer.The coefficient of friction and wear rate under wet friction were reduced by 42.3%and 93.7%compared to the pure EP hard layer and 33.0%and 64.2%compared to the pure FEVE soft layer.By conducting EIS tests on the coatings,the single-cycle and double-cycle coatings remained above 10⁷Ω·cm²after 2 d of immersion.The double-cycle structure was 63.6%higher than that of the single-cycle,reflecting better corrosion resistance.The mechanism study shows that the stress in the soft and hard multilayer structure is apportioned from the surface layer to the lower layer,the soft layer absorbs the deformation to buffer the stress,and the hard layer supports to reduce the friction;the multilayer stacked resin covers the corrosion channels generated by the solvent dispersion to enhance the corrosion resistance.Based on a soft and hard multilayer structure,Si O₂-modified epoxy resin loaded with corrosion inhibitor BTA by silanization was used,and fluorocarbon resin was modified with GO.Due to the synergistic lubrication of the lubrication transfer film formed by the surface GO and the Si O₂ bearing effect,the average friction coefficient and wear rate of the particle-modified double-cycle coating for dry and wet friction were reduced by 8.9%and 16.1%,16.3%and 15.6%,respectively,compared with the double-cycle coating of pure resin.The impedance value of the particle-modified dual-cycle was 2.5 times higher than that of the pure resin after2 d immersion in 3.5 wt%Na Cl solution by EIS corrosion test.The coatings’self-repair ability was characterized by EIS and scratch SEM,element mapping,and the damaged coating was corrosion resistant at cracks.When the coating surface is not damaged,the nanoparticles fill the pore defects generated by the curing of the resin matrix,and the lamellar GO and Si O₂ use the"labyrinth effect"to extend the intrusion path of the corrosive medium.When the coating matrix is damaged,the BTA in the epoxy layer is released from the mesoporous Si O₂ pores and dissolved in water,forming a passivation film on the metal surface,blocking the external corrosive substances from further corrosion of the metal,thus enhancing the corrosion resistance.Linear grooves and square pits were constructed using the template method on the surface fluorocarbon of the particle-modified double-cycle coating.The friction coefficients of the grooves and pits were reduced by 57.7%and 34.6%,respectively,compared to the smooth surface coating by friction tests.The surface textured reduces the contact area to the abrasive surface and collects the abrasive chips to reduce the abrasive particle wear.After 7 days of immersion in acid,alkaline and salt solutions,the texturized surface coating still had a higher water contact angle than the smooth surface.The textured morphology forms gas cavities,reducing the wettability of liquids and decreasing corrosion.The study provides a new approach to the enhancement of wear and corrosion resistance of coatings,and reveals the role of coupled bionics of multilayer structure and surface texture in enhancing the wear and corrosion resistance.