Preparation And Corrosion Resistance Of Superhydrophobic Surfaces On Copper/Magnesium Alloy Substrates

Superhydrophobic surface have attracted tremendous interest in both fundamental research and industrial application due to their special functions and potential application.In recent years,superhydrophobic surfaces have been successfully prepared inspired by the superhydrophobic structures of animals and plants.However,most of the reported methods require sophisticated equipment,complicated process and harsh experiment condition.Therefore,it is urgent to explore simple,low-cost and environment-friendly preparation methods which can be applied to large-scale production.Three kinds of superhydrophobic surfaces with different chemical composition of and good performance were fabricated successfully by using simple,fast,environment-friendly and low-cost methods.The morphologies,chemical composition and wettability were observed.We also test the corrosion resistance and stability of samples.Theoretical research and experimental results show the superhydrophobic coating prepared by these methods on metal surface can effectively improve metal performance and further expand its application field.The main research results are as follows:(1)A novel method was reported to prepare a superhydrophobic surface via machine process and stearic acid modification.The morphologies of mental surface can be adjusted though different process parameters.Followed by modification with stearic acid solution,superhydrophobic surface with a static water contact angle as high as 154° was obtained.Compared with the bare substrate,the corrosion current density of superhydrophobic surface in 3.5wt.% NaCl solution is decreased by 2 orders of magnitude.Besides,the as-prepared superhydrophobic surface possessed good chemical stability.This simple,efficient and environment-friendly method can be applied to achieve large area production of superhydrophobic surfaces.(2)A generalized route for environmentally-benign and cost-effective construction of superhydrophobic surface on magnesium substrate.This method used alcohol and stearic acid as chemical reagent,which offers a unique clue for the rational fabrication ofsuperhydrophobic surface.The surface of rough structure obtained after etching and modification is micro-nano structure with the contact angle as high as 155 ° after being modified by low surface energy.The tests in 3.5 wt.% NaCl solution.indicate that corrosion current density decreased two orders of magnitude,the corrosion potential of superhydrophobic surface is 1547 mV more positive than the bare substrate,which means the surface of the magnesium alloy corrosion resistance increased significantly.The superhydrophobic surface also has good chemical stability.(3)Hydroxyapatite/fatty acid superhydrophobic coating was prepared by chemical deposition on magnesium alloy surface.This method can reduce the corrosion rate of magnesium alloy and can be applied in the field of biomaterials.The microstructure of superhydrophobic surface is consist of needle-like hydroxyapatite coating micro-nanometer scale,combination well with magnesium alloy substrate.After being modified by stearic acid,the contact angle of the water droplet is 154.5 °,indicating that the superhydrophobic characteristics have been obtained.The results show that the corrosion potential of the superhydrophobic surface is increased by two orders of magnitude,the corrosion potential of superhydrophobic surface is 139 mV more positive than the bare substrate,demonstrating the corrosion resistance of magnesium alloys is improved obviously.This rapid,simple,low-cost,safe and environmentally friendly preparation method can further expand the application field of magnesium alloys.