Study On Preparation And Anti-corrosion/Wear Mechanisms Of Ti₃C₂T_x-based Epoxy Coating

Corrosion and wear are widely found in rail transportation,chemical machinery,pipeline transportation,ships,aerospace and other fields.The epoxy coating is the“Nemesis”of corrosion and wear.This physical protective coating on the surface of major equipment can avoid rapid failure.However,due to the disadvantages of poor weather resistance,brittleness and weak scratch resistance,the performance limit of traditional epoxy coating is far lower than the service requirements.Fortunately,two-dimensional layered Ti₃C₂T_x MXene with high mechanical properties,large specific surface area,good electrical and thermal conductivity has great potential to improve the weak protection performance of epoxy coatings.In this paper,based on the performance advantages of Ti₃C₂T_x,the interface and performance of Ti₃C₂T_x based epoxy coating are regulated,and the corrosion and wear behavior of the epoxy composite coating is systematically studied.Furthermore,based on the corrosion and wear behavior of epoxy composite coating,the relationship between interface state,multi-functional modification and the anti-corrosion/wear of coating is discussed,revealing the protection mechanism of high performance Ti₃C₂T_x based epoxy coating system in harsh environment.In the research process,few-layered Ti₃C₂T_x MXene is obtained by etching/exfoliating Ti₃Al C₂ MAX parent phase via liquid phase method;high-performance Ti₃C₂T_x based fillers and epoxy composite coatings are prepared by nano-material functional modification and composite technology,respectively;the microstructure,phase,chemical composition and structure of filler,coating and matrix are characterized by serial surface/interface analysis techniques including scanning electron microscopy,transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy;the anti-corrosion/wear performance of Ti₃C₂T_x based epoxy coating is analyzed by water absorption test,salt spray test,electrochemical technology and reciprocating sliding friction test.This paper enriches the application of Ti₃C₂T_x MXene in material protection field,and solves a series of problems existing in the practical application of Ti₃C₂T_x based epoxy coating,improving the upper limit of protection performance.It has important theoretical significance and engineering application value to meet the long-term,efficient and safe service of major equipment in harsh environment.The main conclusions are as follows:1.Study on the protective mechanism of Ti3C2Tx hybrid epoxy coating on matrixAccording to electrochemical and friction tests,Ti₃C₂T_x can enhance the corrosion and wear resistance of epoxy coating.Subsequently,due to the high electrical conductivity of Ti₃C₂T_x and the weak adhesion strength of Ti₃C₂T_x hybrid epoxy coating,a micro-arc oxidation coating containing a certain porosity is prepared on the substrate surface.The galvanic corrosion of Ti₃C₂T_x disappears and the bonding strength of coating increases,guaranteeing the long-term protection performance of Ti₃C₂T_x hybrid epoxy coating.2.Study on the relationship between Ti3C2Tx adaptation and anti-corrosion/wear of epoxy coatingFor the weak adaptation of Ti₃C₂T_x in epoxy coating,the interfacial interaction of Ti₃C₂T_x in epoxy coating is enhanced by amino functionalization modification.Because the amino-functionalized Ti₃C₂T_x（f-M）avoids the occurrence of agglomeration,the zigzag physical barrier network is formed in the epoxy coating.The water absorption and corrosion susceptibility of f-M hybrid epoxy coating is obviously reduced.Meanwhile,the improved deformation resistance of f-M hybrid epoxy coating and the friction lubrication film formed at the friction interface by well-dispersed f-M can reduce the wear rate of the coating.Therefore,the strong adaptability of Ti₃C₂T_x can significantly enhance the anti-corrosion/wear resistance of epoxy coating.3.Enhancement mechanism of protective efficacy of well-dispersed Ti3C2Tx hybrid epoxy coatingIn order to solve the problem of random arrangement of Ti₃C₂T_x and further improve the protection upper limit of Ti₃C₂T_x hybrid epoxy coating,the distribution orientation of positive Ti₃C₂T_x（f⁺-Ti₃C₂T_x）in epoxy coating is controlled by electric field induced alignment technique.Under the action of electric field,f⁺-Ti₃C₂T_x can realize ordered orientation or even parallel arrangement through torque and the repulsion between f⁺-Ti₃C₂T_x sheets.The parallel arrangement array gifts the internal physical barrier network with the highest tortuosity,significantly prolonging the diffusion period of corrosion media.Moreover,in the friction process,f⁺-Ti₃C₂T_x with parallel arrangement increases the deflection and branch of crack propagation inside the coating,and decreases the peeling of the coating.In view of the insufficient corrosion protection effect of Ti₃C₂T_x hybrid epoxy coating in the late exposure period,a ZIF-8 nanocontainer-loaded amino-functionalized Ti₃C₂T_xfiller（f-Ti₃C₂T_x-ZB）with p H stimulation response mechanism is prepared,achieving the passive and active cooperative protection of epoxy coating.The physical barrier network established by filler can delay the infiltration of corrosive media;corrosion reactions at the coating/metal interface induce the release of corrosion inhibitors from nanocontainers.Because single doping Ti₃C₂T_x is insufficient to improve the performance of epoxy coating,Ti₃C₂T_x/graphene composites with wrapping structure is prepared and used as filler to enhance the protective performance of epoxy coating in corrosion and friction coupled conditions.At the same time,the wear resistance mechanism of the coating system is described from friction interface contact behavior,coating mechanical properties and packing enhancement.4.Optimizing Ti3C2Tx based epoxy coating and verifying its protective performanceBy integrating the structure and performance advantages of the coatings prepared in this paper,the multi-component compounding technology is adopted.Ti₃C₂T_x based epoxy coating is constructed with the optimal formulation and design scheme.The amino-functionalized Ti₃C₂T_x loaded ZIF-8@BTA nano-container fillers with strong interfacial effect are oriented in epoxy coating（f⁺-Ti₃C₂T_x-ZB@EP）.The upper limit of protective performance of epoxy composite coating is obviously increased,achieving the optimization of coating formulation and multi-function coordination.According to the comparative analysis results of key performance parameters of f⁺-Ti₃C₂T_x-ZB@EP and other typical coatings in this paper,the feasibility and scientificity of the key technology of continuous optimization in anti-corrosion/wear of epoxy coating with high quality Ti₃C₂T_xis verified.