Study On Bionic Fabrication And Anti-freezing Adhesive Behavior Of Superhydrophobic Aluminum Surface

Aluminum and its alloys are widely used in industrial production and daily life due to its excellent physical and chemical properties.However,aluminum alloy surface easily produce icing problems,which affect their normal function in harsh weather environments.Therefore,how to improve anti-icing ability of the aluminum and its alloy are important in the practical application.The main forms of ice include deposition ice and supercooled water droplets freeze,if supercooled water droplets or ice from the beginning not adhere on the surface of Al alloy in low temperature,it will not cause heat conduction,also cannot crystallize into ice drops,the surrounding ice drops will not be recrystallization.It is the most intuitive,direct and effective way to prevent freezing on the surface of an aluminum alloy with the surface of a nonstick water droplet(superhydrophobic).Many biological materials have superhydrophobic,low adhesion and anti-icing properties in nature.They can provide important bionics inspiration and new technology for aluminum alloy active ice protection.In this study,The biomimetic superhydrophobic surfaces were successfully fabricated by high speed wire electrical discharge machining(HS-WEDM)on a 7075 aluminum alloy without any chemical modification.Meanwhile,the wettability,the contact time,and the corresponding superhydrophobic mechanism of the artificial superhydrophobic surface were investigated.The artificial surfaces have a high apparent contact angle of 150°~160° with a sliding angle less than 5° and showed a good superhydrophobic property.Wettability,contact time,and the corresponding superhydrophobic mechanism of artificial superhydrophobic surface were investigated.The results indicated that the micro-scale array microstructure was an important factor for the superhydrophobic surface,while different array microstructures exhibited different effects on the wettability and contact time of the artificial superhydrophobic surface.The length(L),interval(S),and height(H)of the array microstructure are the main influential factors on the wettability and contact time.The order of importance of these factors is H > S > L for increasing the apparent contact angle and reducing the contact time.The combination(L=180?m,S=250?m,H=200?m)is the preferable set of these factors and levels for the apparent contact angle,while the corresponding preferable set for the contact time(L=180?m,S =300?m,H=400?m),which has guiding significance in our future work to reducing the contact time by changing in surface parameters.The anti-icing property of bionic superhydrophobic surface with viscosity characteristics was studied.Results showed that the water becomed ice on the bionic sample surface was spherical,and that becomed ice on the substrate surface was spreading;icing and deicing cycle test,anti-icing properties of biomimetic surfaces after anti-icing test was not destroyed.The micro structure of the sample surface was not damaged,showing a good hydrophobic stability.The freezing time of water droplets on the surface was delayed,showing a better anti-icing property.The micro structure and water volume is the main factor affecting the freezing time of water droplet.Preparation of biomimetic superhydrophobic surfaces of the samples can not only greatly reduce the adhesion strength of ice,but it also reduce the accumulation of ice.