Study On Corrosion Process Of Pure Copper And Its Anti-corrosion Based By Superhydrophobic Coatings

Seawater is a complex solution of electrolytes.Metallic materials are susceptible to corrosion in the marine environment.Serious economic loss is caused by material corrosion and failure every year.In recent years,methods have been emerged to protect metals by using coatings to isolate the metal substrate from corrosive medium.However,coatings are prone to failure during long-term contact with the water phase,so coatings'protection time is short.In this paper,the corrosion behavior of copper in hot and humid environment is first studied,and the initial corrosion law of copper is explored.Then two kinds of composite fluid coatings were prepared on copper substrate by electrodeposition method and anodization method,and the corrosion resistance of the coatings was evaluated.The specific content includes:?1?The initial corrosion law of copper induced by NaCl was studied by constructing hot and humid environment.The samples were characterized by XRD,SEM,weight loss test and electrochemical test.In the early stages of corrosion,the materials were corroded by the stimulation of Cl^-and other ions.In hot and humid environment,granular and needle-like structures appeared on the surface of the material.In the natural environment,the early performance is formation and fracture of oxide films on the surface of material,and micro-cracks appear.?2?The potentiostatic electrodeposition method was used to build dendritic Cu₂O on Cu substrate.Superhydrophobicity was achieved by surface modification with dodecanethiol.The composite fluid injection surface was prepared on the surface of copper by mixing the modified Fe₃O₄ nanoparticles with oil.The composite fluid coatings exposed to atmospheric environment for 20 days,Z_0.01Hz and I_coor are 6.05×10⁹?·cm^-2 and 9.08×10^-8mA·cm^-2,respectively.The composite fluid coatings were immersed in 3.5 wt.%NaCl solution for 20 days,the Z_0.01Hz and I_coor are 4.51×10⁶?·cm^-2 and 3.49×10^-4mA·cm^-2,which indicates that the hydrophobic nanoparticles can lock the oil phase and the protection time of the coatings is increased.Therefore,CLIS provides a new way to protect copper from corrosion.?3?Cu?OH?₂ nanoneedle structure was constructed on the Cu matrix by using electrochemical anodization.Superhydrophobic wettability was achieved by Surface modification with dodecanethiol.Hydrophobic ZnO nanoparticles modified with n-dodecanethiol were mixed with oil to prepare a composite fluid injection coating on copper surface.After soaking in seawater for 20 days,Z_0.01Hz and I_coor of the CLIS Cu were 1.30×10⁹?·cm^-2 and 1.36×10^-5mA·cm^-2,respectively.After soaking in SRB culture solution for 10d,Z_0.01Hz and I_coor of the CLIS Cu were 1.25×10⁵?·cm^-2 and1.02×10^-3mA·cm^-2,respectively.It is shown that the composite coating not only has good resistance to Cl^-corrosion,but also significantly enhances the corrosion inhibition ability to biological corrosion?MIC?caused by sulfate reducing bacteria?SRB?when the Cu metal is coated with composite fluid injection coating.