Research On Fabrication And Property Of Superhydrophobic 30Cr2Ni2WVA Aeronautic Steel

Superhydrophobic surface is a kind of bionic functional surface with special wettability.Because of the potential applications in directional transportation of droplet,anti-icing,oil-water separation,self-cleaning,corrosion protection,drag reduction and so on,superhydrophobic surfaces have attracted the attention of researchers.As a kind of alloy,steel is widely used in the production and life of human society because of its excellent processability,assembly ability and other properties.Among steel,as a kind of high-strength steel,aeronautic steel is widely used in aircraft.The preparation of superhydrophobic surface on the aeronautic steel play an important role in expanding the application range of aeronautic steel and has potential research significance.Nowadays,the preparation method of superhydrophobic steel is diversity,while,there are some problems,such as poor environmental friendliness,high cost,poor durability and so on.To solve the above problems,we used neutral electrolyte to fabricate superhydrophobic surface on the aeronautic surface by electrochemical etching,and durability and applications of surface were also studied.The main work contents and research result as follow:(1)Micro/nano-scale roughness structures were simple and efficiently fabricated by electrochemical etching on the 30Cr2Ni2WVA aeronautic steel.Moreover,superhydrophobic aeronautic steel was obtained by using low-surface-energy modification.This method was simple,low cost,and had excellent environmental friendliness.(2)Single-factor experiments were applied to explore the influence of electrochemical machining parameters(current density,concentration of electrolyte,the electrochemical etching processing time)on the macrostructure and wettability of superhydrophobic aeronautic surface.Moreover,the optimum processing parameters were obtained by a comprehensive consideration of cost and efficiency.The results show that the optimum processing parameters to develop superhydrophobicity on 30Cr2Ni2WVA aeronautic steel were 25 wt%Na NO₃ solution as the electrolyte,5 A·cm^-2 current density and 60 s etching time.(3)Scanning electron microscopy(SEM),energy-dispersive X-ray analysis(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray diffraction analyzer(XRD)were used to characterize chemical composition and morphologies of superhydrophobic 30Cr2Ni2WVA aeronautic steel which was fabricated by optimum processing parameters.The results show that after electrochemical etching,30Cr2Ni2WVA aeronautic steel was covered by a film which was composed of iron,chromium oxide/hydroxide,and this film has a coral-like micro/nano-scale roughness structure.(4)Linear abrasion test,solid particle impact test,ultrasonic cleaning test,corrosion resistance test,thermal cycling test and ultraviolet exposure test were applied on the superhydrophobic 30Cr2Ni2WVA aeronautic steel which was fabricated by optimum processing parameters to measure surface intensity and chemical durability of the surface.The results show that superhydrophobic 30Cr2Ni2WVA aeronautic steel has excellent surface intensity and chemical durability which can be used in tough conditions.(5)The applications of superhydrophobic 30Cr2Ni2WVA aeronautic steel in anti-icing and self-cleaning were studied.The results show that the retention time of water droplets on the surface was reduced,hence the freezing process was inhibited,showing excellent anti-icing property.Moreover,water droplets that dropped on the surfaces quickly rolled off and took contaminants away,showing outstanding self-cleaning property.