Preparation And Properties Of Superhydrophobic Amorphous Alloy Surfaces

On the surface science to the liquid has extremely hate or very close to the special“emotion”phenomenon called extreme wetting phenomenon,this phenomenon widely exists in nature,such as the lotus leaves.Inspired by such organisms,researchers began to construct extreme wettability surfaces on solid material,such as polymer materials and traditional metal materials,leading to unprecedented development in this field.The results show that the surface energy and the surface roughness are the two most important factors which determine the wetting behavior of the material surface.Although the polymer materials have a low surface energy,but they are easy to be damaged by wear and tear during service.However,due to the“grain effect”,the surface structures of traditional crystalline alloys are difficult to be obtained at micro-nano scales.As a new kind of metal material,amorphous alloy has excellent mechanical properties,corrosion resistance,and has inhomogeneity on the atomic scale,which is convenient for the construction of micro-nano structure.Therefore,amorphous alloy is considered as an ideal material for the preparation of extreme wettability surface.However,the research on the extreme wettability of amorphous alloy surface is still very limited,and it is urgent to further understand the difference of surface wettability between amorphous alloy and crystalline alloy.In this paper,Zr₅₅Cu₃₀Ni₅Al₁₀and Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂bulk amorphous alloys were prepared by non-consumable vacuum arc melting furnance.The X-ray diffraction(XRD),scanning electron microscope(SEM)were carried out on the microstructure characterization,the electrochemical etching method was used to construct different surface rough structure,and then modified by low surface energy of surface chemical modification,preparation of the superhydrophobic surface of amorphous alloy,and the influence factors of the surface wetting behavior of amorphous alloy were analyzed.In addition,by measuring the surface energy of Fe-based,Cu-based,and Zr-based amorphous alloys and their corresponding crystalline alloys,the differences of surface wettability between amorphous alloys in different systems and between amorphous alloys and crystalline alloys were analyzed.The main conclusions are as follows:In this article,through regulating the corrosion current and corrosion time 50 m A,50 min,respectively,and then modified by 1 mmol/L stearic acid.The preparation of the superhydrophobic surface of Zr-based amorphous alloy.By measuring,the WCA was 169±1.7°of the superhydrophobic Zr-based amorphous alloy surface,and the water droplet adsorption ability of the surface was very weak.When sample 3 tilt 5°,the droplets can roll freely on the surface,revealed a great superhydrophobicity.By analyzing the surface morphology,it was found that there were a lot of micro-nano rough structures on the surface,and the CA was the largest when the surface roughness was 4.48?m.Electrochemical test results showed that the corrosion resistance of superhydrophobic Zr-based amorphous alloy was significantly improved.Due to the selective corrosion of Zr-based amorphous alloy atoms,such as Cu,it was easier to form complex micro-nano structurexs.Through analyzing the Cassie-Baxter theory and the Wenzel theory,found that the wetting behavior of superhydrophobic Zr-based amorphous alloy belongs to Cassie-Baxter model,there is a lot of air in the rough structures,prevents liquid wetting,only a small part of the liquid contacts with the solid surface,so the absorption of water droplets is very small.In the preparation of superhydrophobic Fe-based amorphous alloy surface,also using the electrochemical corrosion method to construct the rough structure,regulating the corrosion current and corrosion time 45 m A,10 min,respectively.And thenmodified by 2 vol%CF₃(CF₂)₇CH₂CH₂Si(OCH₃)₃(FAS),the preparation of the superhydrophobic Fe-based amorphous alloy surface,and measured the WCA was154±2.4°.The surface of Fe-based amorphous alloy had a strong adsorption ability to water droplets.When the alloy surfaces were rotated by 90°or even 180°,the water droplets can still be adsorbed on the surface.Comparing the surface of superhydrophobic Zr-based amorphous alloy with Fe-based amorphous alloy,it is found that the surface rough structure with different geometrical size has a great influence on the surface superhydrophobic performance.The Fe-based amorphous alloy surface atomic distribution is relatively uniform,corrosion is relatively uniform,when more than the critical voltage of corrosion,can cause the occurrence of pitting and easier to form the micron grade structure size is larger.The surfaces of Fe-based amorphous alloy belong to the transition state between the Cassie-Baxter and Wenzel model.Due to the large geometrical size of the surface structures,liquid will enter the surface and increase the contact area between liquid and solid,resulting in a strong surface adhesion ability.Furthermore,the Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂,Cu₄₆Zr₄₂Al₇Y₅,Zr₆₅Cu_17.5Ni₁₀Al_7.5,Zr₅₅Cu₃₀Ni₅Al₁₀amorphous alloys with strong amorphous forming ability and their respective crystalline alloys were compared and studied.The CAs of water and ethylene glycol on the alloy surfaces were measured by contact angle measuring instrument.The surface energy of each alloy was obtained by Owens-Wendt theory.The results showed that the free volume?V_fof amorphous alloys with similar composition has a great influence on the surface energy,and?V_fhas a positive correlation with the surface energy,that is,the smaller the?V_fis,the smaller the surface energy is.In addition,the comparison showed that the amorphous alloy has lower surface energy than the homogeneous crystalline alloy.The analysis shows that although the amorphous alloy is metastable and the overall energy is higher than that of the crystalline alloy,the atomic diffusion coefficient on the surface of the amorphous alloy is much higher than that in the body,and the energy is mainly concentrated in the body of the alloy,and the surface energy is low.The amorphous alloy,however,can be considered to have defects everywhere.Compared with the crystalline alloy,the amorphous alloy exhibits higher atomic mobility,so the surface atomic chaos is larger.According to Gibbs free energy law,the surface energy of the amorphous alloy is lower.In this paper,two kinds of superhydrophobic amorphous alloys with different wetting behaviors were prepared,which further expanded the practical application range of amorphous alloys.In addition,the study on the surface energy of different amorphous alloy systems deepens the understanding of the surface wetting behavior of amorphous alloy systems,which is helpful for the design and selection of amorphous systems with low surface energy.It provides a reference for obtaining the surface of amorphous alloy with functional characteristics.