| In recent years,the study of superhydrophobic surfaces has made great progresses,and the research results have come out in an endless stream.Due to the potential applications of superhydrophobic surfaces in self-cleaning,anti-freezing and corrosion resistance,the research on superhydrophobic surfaces has drawn great attentions.The research shows that the construction of superhydrophobic surfaces on the metal substrate can greatly improve the protective ability of the metal surface,especially on aluminum alloy.At present,most of the superhydrophobic surfaces on aluminum alloy are prepared by the method of combining the surface structure of metal and the modification of low surface energy modification.Therefore,it is important to roughen the surface of the material,so as to facilitate the construction of the microstructure.But at present,most of the super hydrophobic surfaces have such problems as harsh preparation conditions and high cost.Meanwhile,stability,especially poor mechanical stability,also severely restricts their applications.Therefore,it is of great significance to carry out the research in this area.This paper takes 6061 Aluminum Alloy as matrix,using chemical etching method for surface treatment,and through the anodic oxidation treatment to construct micro-nano structure,and then modified by stearic acid with low surface energy.Ultimately obtain the superhydrophobic surface,without the need for complex equipment,simple process,low cost.The influence of main experimental parameters on the sample surface wettability: the anodic oxidation voltage,anode oxidation time,concentration of electrolyte,concentration of modified solution and the immersion time of modified solution were studied by single factor variable method,and the best preparation technology was determined.The contact angle of water on the final sample surface was close to 160° and the rolling angle was about 5°,the superhydrophobic surface was obtained.The microstructure was observed by scanning electron microscopy,the results showed that the micro-nano hybrid rough structure composed by micron labyrinth structure and nanometer pore structure on the super hydrophobic surface.This kind of multi-scale structure with low surface energy modification could invade the barrier of water droplets,so that it was difficult for the surface to be wetted.The gas retention rate between the droplet and the structure was 94.9% calculated by the Cassie equation.It shows that the micro-nano structure has large roughness by 3D morphology analysis.The chemical composition of super hydrophobic surface was studied by X ray spectroscopy.The results showed that stearic acid was successfully grafted onto the surface,interact with the micro-nano hybrid rough structure,and the surface super hydrophobicity was obtained.At the same time,the application characteristics of the superhydrophobic surface were studied.Firstly,the stability of the super hydrophobic surface was studied.In static atmosphere after 6 months,the contact angle of the surface was almost unchanged,floating at 156° up and down,which indicated that the super hydrophobic surface was long-term stability.The thermal stability test showed that surface could remain superhydrophobic at 200°C under 12 h indicated that the super hydrophobic surface has good thermal stability.The particulate pollutants on the superhydrophobic surface will be taken away with the falling drops of water,which shows that the super hydrophobic surface has good self-cleanness.The super hydrophobic sample was placed in the subzero low temperature under 24 h,the surface still has no icing phenomenon,and maintains good super hydrophobicity.It shows that the super hydrophobic sample has good frost proof characteristic.It is found that the contact angle of the super hydrophobic sample will have a certain effect under the condition of strong acid,while the strong alkali solution would greatly reduce the contact angle,so the surface should not be applied to the strong alkali environment.The electrochemical test results showed that the corrosion potential of the super hydrophobic surface increased by 1.08 V as compared to aluminum alloy substrate,and the corrosion current density was less than an order of magnitude,indicating that the prepared super hydrophobic surface possessed good corrosion resistance. |
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