Study On The Composite Preparation And Performance Of The Superhydrophobic Microstructure Surface Of Aluminum Alloy

Aluminum alloy is a kind of metal material with excellent comprehensive performance,but it faces serious corrosion problems and seriously affects its service life,which undoubtedly restricts the development of aluminum alloy in aerospace,ship and other machinery industries.In recent years,with the future research of the bionic superhydrophobic surface,it is found that its special surface microstructure can reduce the contact area between the metal substrate and the corrosive medium,which provides a possibility to improve the anti-corrosion performance of the aluminum alloy.In this paper,aluminum alloy is used as the substrate,and the microstructure is constructed by laser and chemical combination,and the superhydrophobic surface is prepared by combining stearic acid(STA)modification.The optimum process parameters were determined experimentally,and the relationship between surface microstructure and wetting properties and corrosion resistance was systematically studied.The main findings are as follows:(1)On the basis of the preparation of superhydrophobic microstructure surface by laser etching and chemical etching in the early stage,this article compared the surface microstructure and contact angles of the super-hydrophobic aluminum prepared by the two kinds of composite preparation methods: chemical etching after laser etching and laser etching after chemical etching.It is found that the superhydrophobic surface processed by chemical etching after laser etching has a more regular and hierarchical microstructure,and the surface contact angle is the largest.So,this method is more suitable.(2)When the superhydrophobic aluminum surface was prepared by first laser etching and then hydrochloric acid etching,a hydrophilic surface has been obtained and then modified with STA solution to get a superhydrophobic surface.It is found that the laser power,hydrochloric acid concentration and etching time have great influence on the surface microstructure and hydrophobic properties.When the power is 20 W,the concentration is 2.9M,and the time is 45 min,the surface contact angle is up to 156.8°.(3)After the aluminum surface etched with laser and sodium hydroxide,the surface microstructure has been obtained,and then modified with STA solution to get a superhydrophobic surface.It is found that the laser power,sodium hydroxide concentration and etching time also have a great influence on the surface microstructure and hydrophobic properties.When the power is 30 W,the concentration is 0.1M,and the time is 6 minutes,the surface contact angle is up to 155.1°.The prepared sample was found that it has a drag reduction rate of 15.5% by a fluid drag reduction test.(4)Compared with the original aluminum alloy surface,the prepared superhydrophobic aluminum surface has a more correct corrosion potential and a smaller self-corrosion current density.The superhydrophobic aluminum surface obtained by sodium hydroxide etching after laser etching has better corrosion resistance and higher temperature threshold due to its different surface composition.