Nanosecond Laser Construction Of Superhydrophobic Micro-nano Structure On Aluminum Alloy Surface

Based on the anti-corrosion requirements in the wide application of aluminum alloys in various fields,this paper proposes an efficient and practical new method for constructing super-hydrophobic micro-nano structures based on the laser remelting technology of anodic aluminum oxide film.In the method,a nanosecond pulse laser is used to remelt the entire surface on the surface of the porous barrier film layer of anodized aluminum alloy to construct a densely distributed micro-nano structure.In this paper,6061 aluminum alloy is used as the research object to study the influence of different laser remelting parameters on the micro-nano structure morphology and the superhydrophobic surface wettability,corrosion resistance and self-cleaning performance effects of perfluorosilane chemical modification.The main results are as follows:(1)The laser remelting parameters have a significant influence on the construction of micro-nano structures.The spot overlap rate is greater than 99%,and dense micro-nano clusters are formed on the surface of the anodic aluminum oxide film,and air pockets are formed between each other.And the micro-nano cluster structure will gradually disappear with the increase of the laser pulse width and become a regularly arranged fused corrugated structure.Laser power and scanning speed have a certain relationship with the construction of surface micro-nano structure.When the laser power is lower than 5W,the surface of the film absorbs laser energy and melts,vaporizes,and condenses after bubble explosion to form densely distributed micro-nano structures.And when the scanning speed is 10mm/s,pits will appear randomly on the surface of the remelted micro/nano structure.When the laser power is higher than 5W,the film surface will melt,vaporize and explode after absorbing the laser energy,and plasma will also be generated.The impact force of the plasma jet makes the remelted surface to form holes.And when the scanning speed is10mm/s,intermittent holes appear on the surface of the remelted micro/nano structure.With the increase of the scanning speed,the pores appearing on the surface of the remelted micro/nano structure are arranged regularly.The porous structure of the anodic aluminum oxide film makes the laser energy transfer in the depth direction better than the radial direction,so the line spacing is an important factor affecting the integrity of the remelted surface.(2)The micro-nano structure constructed on the surface of the anodic aluminum oxide film by laser remelting,after chemical modification with perfluorosilane,is combined with the—CF_3,—CF₂—group film layer on the surface,and the surface wettability is changed by super affinity The water becomes super-hydrophobic,and the contact angles are all greater than 153°,and the maximum value can reach157.03°.The rolling angle of the surface is extremely low,so the super-hydrophobic surface has self-cleaning performance,and is not polluted by pollutants such as high-absorptive toner,carbon ink,and silt suspension.Electrochemical corrosion shows that the superhydrophobic surface has good corrosion resistance,and the surface corrosion inhibition rate is greater than 92.68%.