High-strength Corrosion-resistant Foamed Aluminum Epoxy Resin Composite With Superhydrophobicity

Aluminum foam epoxy resin composite was widely used in transportation,aerospace and construction industries because of its low density,strong impact resistance,easy processing and installation,sound insulation and noise reduction.In this paper,a composite epoxy resin material with excellent corrosion resistance,hydrophobicity and wear resistance was designed and prepared,and it was poured into the micropores of foamed aluminum material by vacuum heat assisted injection technology,so as to obtain an organic-metal composite material with excellent superhydrophobicity,wear resistance,corrosion resistance and good mechanical properties.The prepared materials had certain application potential in the fields of airplane wings,wind turbine blades,high-speed train surfaces and the like.The main contents of this paper are as follows:（1）In order to obtain functionalized nano-TiO₂/epoxy resin composites with excellent hydrophobic and anticorrosive properties,firstly,the surface of nano-TiO₂was functionalized with trimethoxyheptafluorodecyl silane andγ-aminopropyl triethoxysilane.Diethyltriamine used as curing agent was fluorinated with perfluorooctyl methacrylate by Michael addition reaction.Finally,two kinds of functionalized nano-TiO₂/epoxy resin composites were prepared by one-step method and two-step method respectively.FT-IR and ¹HNMR were used to analyze the phase composition and microstructure of diethylenetriamine fluoride and functionalized nano-TiO₂.SEM characterization results show that the functionalized nano-TiO₂/epoxy resin composite prepared by two-step method had more uniform rough surface,lower internal porosity and gradient structure between epoxy resin layer and functionalized nano-TiO₂layer.Friction experiments prove that the superhydrophobicity of functionalized nano-TiO₂/epoxy resin composite prepared by two-step method had certain mechanical stability.Under the load of 1.25 k Pa,it can keep superhydrophobicity after sliding for 3.5 m on the surface of 500 mesh sandpaper.Tafel polarization curve and EIS show that the functionalized nano-TiO₂/epoxy resin composite prepared by the two-step method had excellent corrosion resistance,with the water contact angle of 164.9°,the current density i_corrof only 1.53×10^-8A·cm^-2and the corrosion rate v_corrof 1.78×10^-4mm·y^-1,which was two orders of magnitude superior to the pure epoxy resin material.The results show that the prepared functionalized nano-TiO₂/epoxy resin composite has excellent wear resistance and corrosion resistance,and has a certain application prospect in the field of material protection.（2）In order to improve the wear resistance of superhydrophobic surface of composite epoxy resin material,fluorine containing prepolymer（FCP）was prepared from trimethoxy heptafluorodecyl silane andγ-aminopropyl triethoxysilane.The surface of nano-SiC was functionalized with trimethoxy heptafluorodecyl silane andγ-aminopropyl triethoxysilane.Finally,two kinds of functionalized nano-SiC/epoxy resin composites were prepared by one-step method and two-step method respectively.The phase composition and microstructure of FCP and functionalized nano-SiC were analyzed by FT-IR.SEM image characterization results show that the functionalized nano-SiC/epoxy resin composite prepared by two-step method had similar morphology and structure to that of functionalized nano-TiO₂/epoxy resin composite,but the superhydrophobic surface was closer than that of the latter.The friction experiment proves that the wear resistance of the superhydrophobic surface of the prepared functionalized nano-SiC/epoxy resin composite was remarkably improved,and it can still maintain superhydrophobic property after sliding for 13 m on the surface of 500 mesh sandpaper under the load of 1.25 k Pa.Tafel polarization curve and EIS test results show that the functionalized nano-SiC/epoxy resin composite had excellent corrosion resistance.The corrosion rate of the protected sample in 3.5wt%Na Cl solution decreases to 7.608×10^-4mm·y^-1,and the corrosion resistance of the sample increases to6.416×10⁵kΩ·cm².After 28 days of immersion in 3.5wt%Na Cl solution,it still had good corrosion resistance.By improving the raw materials and process,the wear resistance and corrosion resistance of the prepared functional nano-SiC/epoxy resin composites are improved.（3）Using FCP,functionalized nano-SiC,epoxy resin and aluminum foam as raw materials,a kind of aluminum foam epoxy resin composite with excellent performance was successfully prepared by using heat-assisted vacuum injection technology.Aluminum foam epoxy resin composite with unique interpenetrating network structure shows excellent wear resistance,bending resistance,tensile resistance and corrosion resistance due to the unique foam structure of aluminum foam and excellent physical and chemical properties of modified epoxy resin.SEM show that the filling efficiency of aluminum foam by epoxy resin was over99%,and the epoxy resin was closely combined with foam metal.The results of water contact angle show that the static water contact angle of the prepared composite can reach 155.7°at the highest,and the prepared superhydrophobic surface can keep superhydrophobicity even after the friction distance of 14 m under the pressure of 2 k Pa.Tafel polarization curve and EIS results show that aluminum foam epoxy resin composite after superhydrophobic treatment had excellent corrosion resistance,with the corrosion current i_corras low as1.399×10^-9A·cm^-2and the highest value of Z_0.01Hzas high as 7.74×10⁷ω·cm².The load-displacement curve data of aluminum foam epoxy resin composite three-point bending test was collected by the universal testing machine（WDW-100C）controlled by microcomputer.Load-displacement curve data of aluminum foam epoxy resin composite tensile fracture experiment were collected by using double-column desktop electronic universal material testing machine（INSTRON 2369）.The test results show that,compared with AF,the injection of epoxy resin greatly improves the bending performance of AFE.The bending strength of aluminum foam epoxy resin composite can reach 73.20 MPa,the bending stiffness can reach 2548 MPa,the tensile strength can reach 42.09 MPa and the Young’s modulus can reach 2934 MPa.The friction experiments of aluminum foam epoxy resin composite were carried out with a high-speed reciprocating friction tester（HRS-2M）.The experimental results show that the wear rate of all aluminum foam epoxy resin composite samples was less than 2.181×10^-3mm³/Nm.The prepared AFE successfully combines the advantages of AF and functional nano-SiC/epoxy resin composites,and shows excellent performance in bending,tensile,corrosion resistance and wear resistance.