Fabrication And Properties Of Copper-based Special Wettability Functional Surface Micro-nano Structure

Brass have been used widely as mechanical components such as precision instruments,ship parts due to its good mechanical properties,wear resistance and easy processing properties.However,brass is prone to be corroded in moist environments and chloride-containing solutions.Therefore,its life and application field are severely restricted.Inspired by biological surfaces in nature,superhydrophobic surfaces with excellent hydrophobic properties have great potential for solving corrosion problems.In this paper,etching,electrochemical deposition and heat treatment techniques were used to construct special wettability functional surfaces on H62 brass substrate,and the formation mechanism,transition mechanism,corrosion characteristics and adhesion characteristics of the special wettability functional surface were studied.The main conclusions are as follows:(1)A simple,low-cost chemical etching method was used to construct a hierarchical micro-nano structure on a brass substrate.After being modified with fluorosilane,a superhydrophobic surface with a contact angle of 150.7±1.1° and a roll angle of 9.3±0.8°was obtained.The formation mechanism of superhydrophobic surface was revealed by analyzing the morphology and composition of superhydrophobic surface.Electrochemical experiment results show that the superhydrophobic surface has good corrosion resistance and the corrosion inhibition efficiency is 87.5%.The stability tests show that the mechanical stability and the long-term durability in NaCl solution were poor.(2)A more pronounced hierarchical micro-nano structure was prepared on the brass substrate by the etching and electrodeposition.After being modified with fluorosilane,the contact angle was as high as 159.5±1.7°and the rolling angle was only 3.3±0.6°,which had excellent water-repellent performance.Electrochemical test results show that the superhydrophobic surface has excellent corrosion resistance and the corrosion inhibition efficiency is as high as 92.35%.When the superhydrophobic surface was immersed in 3.5wt%NaCl solution for 10 days,the impedance modulus decreased slightly,still as high as 10^4.045?.cm².Through tape peeling and abrasion experiments,it was demonstrated that the superhydrophobic surface has excellent mechanical stability.In addition,the superhydrophobic surface also has good self-cleaning performance and chemical stability.(3)A more pronounced hierarchical micro-nano structure was prepared on the surface of the brass substrate by etching and heat treatment.After stearic acid modification,the contact angle was as high as 159.7±1.2°,the rolling angle was only3.1±0.6°,and the wettability was greatly enhanced.The prepared superhydrophobic surface can realized the reversible wettability transition of superhydrophobic/superhydrophilic through temperature and re-modification.The entire transition process takes only 230s.Corrosion resistance test results show that compared with polished samples,superhydrophobic/superhydrophilic surfaces have excellent corrosion resistance.Due to the extremely small solid-liquid contact area,the corrosion resistance of the superhydrophobic surface is particularly outstanding,and the corrosion inhibition efficiency is as high as 98.8%.Stability tests show that the prepared superhydrophobic surface has excellent long-term durability in a 3.5wt%NaCl solution.Even if immersed in NaCl solution for 10 days,the impedance modulus is still higher than that of the polished sample.The superhydrophobic surface also has excellent mechanical stability performance,even when the abrasion distance reaches 300cm,the substrate surface still shows excellent hydrophobic performance.In addition,superhydrophobic surface also has excellent self-cleaning properties and chemical stability.