| Since the 21st century,metallic materials will still be important structural and functional materials in the development of human society.However,severe corrosion occurs when metals are exposed to corrosive environments for a long time.In recent years,inspired by the"lotus effect",researchers have focused on bionic superhydrophobic surfaces in applications such as metal corrosion prevention,self-cleaning,and oil/water separation.Because corrosion is initiated at the interface between the aqueous medium and the substrate,superhydrophobic surfaces can effectively resist corrosion and prolong service life.In terms of oil/water separation,many preparation processes of super-hydrophobic materials are costly,cumbersome,or polluted caused by using fluorine.Aimed at low-cost,environmental protection,facile preparation and application,therefore,this study prepared fluorine-free and high corrosion resistance super-hydrophobic materials.In this study,the highly adhesive,uniform,dense metallic alloy coatings with micro-nano roughness were prepared on the substrate surfaces by low-cost,easily controlled electrodeposition method.Subsequently,the as-prepared metallic alloy coatings were modified with a low surface-energy substance to achieve the superhydrophobicity.The prepared superhydrophobic coatings were characterized and tested in terms of corrosion resistance and other properties,and the formation mechanism of the superhydrophobic surface was studied.Simultaneously,the superhydrophobic coatings were applied to the oil/water separation.The main research contents are as follows:(1)The Zn–Fe alloy coating was obtained on the surface of carbon steel by potentiostatic polarization electrodeposition in a basic cyanide-free glycerol electrolytic bath with zinc and iron salts.The super-hydrophobic surface with water contact angle(WCA)up to 166°was obtained after surface modification with tetradecanoic acid.The prepared super-hydrophobic coating was of self-cleaning,antifouling,impact resistance,high adhesion,and good corrosion resistance.In the electrochemical test,the corrosion current(icorr)and corrosion rate(CR)of the sample were reduced respectively from 1.66×10–4 A?cm–2 and1.95 mm?a–1(naked carbon steel)to 2.65×10–6 A?cm–2 and 0.02 mm?a–1,showing high corrosion resistance.Furthermore,the formation mechanism of the superhydrophobic coating was discussed via the calculation of the interfacial free energy of the superhydrophobic coating.(2)A superhydrophobic Zn–Fe alloy coating was applied to the surface of foam iron to prepare a superhydrophobic foam iron with fluorine-free,mechanical stability,durability,and high oil/water separation efficiency.In the electrochemical test,icorr and CR of the superhydrophobic foam iron were reduced from 1.27×10–3 A?cm–2 and 14.95 mm?a–1(the original foam iron)to 1.01×10–4A?cm–2 and 1.18 mm?a–1,respectively.In the oil/water separation test,the oil/water separation efficiency of the prepared superhydrophobic foam iron was as high as99.3%,and the formation process of the superhydrophobic foam iron was also studied.Additionally,a device for continuous oil/water separation was designed.(3)To further improve the corrosion resistance of superhydrophobic foam iron,a superhydrophobic Zn–Fe–Co–Ni–Mn high-entropy alloys coating was prepared for oil/water separation.Electrochemical tests revealed that the prepared superhydrophobic high entropy alloy coating was of a lower corrosion current(2.28×10–5 A?cm–2)and corrosion rate(0.27 mm?a–1)than the superhydrophobic Zn–Fe alloy coating,showing excellent corrosion resistance.Simultaneously,the self-cleaning,wettability and oil/water separation efficiency of superhydrophobic high-entropy alloy coated foam iron were studied,and the formation mechanism of superhydrophobic high-entropy alloy coatings was discussed. |
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