| Aluminum alloy has good appearance,light texture,easy processing and forming,no low temperature brittleness,and strong recyclability.At present,the amount of aluminum alloy used in shipbuilding is rapidly increasing,and it is widely used in the hulls,window windows,various ladders and springboards of high-end luxury ships.In recent years,the development of superhydrophobic surface preparation technology provides a new way to improve the properties of metal surfaces.In this thesis,6061-T6 aluminum alloy is selected as the research object,and the influence of the main process parameters of laser marking on the surface etching morphology is analyzed.On this basis,laser marking and its composite technology are used to prepare micro-nano graded rough structures.The wettability of the hydrophobic structure on the aluminum alloy surface is studied,and the main research results are listed as follows:(1)The super-hydrophobic surface was prepared by laser etching of 6061 aluminum alloy and modification with stearic acid ethanol solution.The laser marking speed,line spacing,etching times and other parameters were adjusted,and the microstructure shape after laser etching was discussed.The relationship between appearance and surface wettability.The results show that the distance between laser marking lines mainly affects the protruding structure around the pit structure.The reduction of the distance between the laser scanning lines will increase the degree of influence between adjacent strip pit structures.The change of laser scanning speed will change the volume of molten aluminum The size and the impact force of the laser beam on the unit area will also be different,which will have a corresponding impact on the size and morphology of the protrusion structure.When the laser marking line spacing is 0.05mm and the scanning speed is 30mm/s,the static contact angle is about 161.3°,and the rolling angle is about 6.5°.After being modified by low surface energy substances,the surface hydrophobicity is the best.The corrosion current density of the superhydrophobic film is 7.179×10-9A·cm-2,which is 2 orders of magnitude lower than that of the polished aluminum alloy surface.The contact angle of the super-hydrophobic film drops to 149.6°after sliding and rubbing 400mm,losing its super-hydrophobic properties,and its mechanical stability needs to be further improved.(2)The cobalt layer is electrodeposited on the surface after laser etching.Compared with the cobalt layer deposited by anodic oxidation,the secondary zinc immersion electrodeposited cobalt layer has a better deposition effect.When the current density is4m A/cm2,the cobalt coating is deposited well after 20min After the modification,the static contact angle of the surface is about 160.4°,and the rolling angle is about 1.5°.The hydrophobic effect is obviously improved.The corrosion current density of the super-hydrophobic coating is 5.304×10-8A·cm-2,which is better than polished aluminum alloy surface.94.1%.After 700mm of sliding friction,the contact angle drops to 150.4°,and the surface remains hydrophobic.At the same time,the coating exhibits excellent self-cleaning effects.(3)Hard anodizing is used to form porous nanotubes on the surface of aluminum alloy,and laser marking is performed on the oxide film to construct a hydrophobic surface.The laser marking speed is 10 times higher than that of direct etching on the aluminum alloy surface to prepare a super-hydrophobic film.After modification,the static contact angle is about 167.7°,and the rolling angle is about 1.5°.The corrosion current density of the super-hydrophobic film is 1.160×10-7A·cm-2,which is nearly an order of magnitude lower than that of the polished aluminum alloy.When the friction distance is 850mm,the contact angle of the film surface still reaches 150.6°,and the mechanical stability of the film is further improved. |
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