The Research Of Bionic Hydrophobic Surface Induced By Femtosecond Laser

Superhydrophobic surface is the surface with contact angle greater than 150° and rolling angle less than 10° . The main factors for the formation of superhydrophobic surface are micro-structure and low surface energy. Based on related research results,the micro-structure with specifically physical or chemical properties play an important role for the promotion of materials' hydrophobic property. Titanium alloy and composites have the advantages of good thermal performance, high strength, etc.And it's also applied in aviation,aerospace and other fields. However, most titanium alloys and composites' surface have no self-cleaning (hydrophobicity). Therefore, it is of great significance to fabricate hydrophobic titanium alloy and composites surface for expanding the application of titanium alloy and composites in these fields and meeting the needs of special applications. At present, the technology of ultrafast laser,especially micro-nano processing technology of femtosecond laser, has three major characteristics of ultrafast time-resolved, high peak power density and high focusing ability.lt breaks the restrictions of material and size, it also has the application prospect of preparing micro-nano structure widely, and it's expected to become the effective way to solve preparation of micro-structure of titanium alloy and composites.According to the above requirements and background, we use the micromachining technology of femtosecond laser to process surface of titanium alloy and composites by inducing, direct writing, and processing with low surface energy modification, focuse on the influence of femtosecond laser parameters on change law of micro-nano structure, systematically characterize the surface morphology under different process parameters, detailedly test and analyze wetting properties of two materials in this paper.The main conclusions are as follows:(1) With changing femtosecond laser energy density and pulse number, the micro structure of the titanium alloy surface produced are always experiencing four stages,including laser induced periodic surface structure phase, classic ripple structure phase,classical and non classical ripple coexist phase, micro-hump structure with classic ripple structure.(2)Through processing composites,relatively regular array of prism or square can be made, and the length of prism is 30?m?230?m. The size and shape of prism are basically the same under different parameters of angle parameters (30°,60° and 90°),but the appearance of prism will change with energy density, scan spacing and scan times.(3) Study shows that hydrophobic property were obtained on titanium alloy surface with micro-nano structure and composites surface with micro-prism combined with hydrophobic coating. The contact angle of titanium alloy surface processed with energy density 0.74J/cm2,pulse number 256, scanning spacing 30?m and composites surface processed with energy density 0.37J/cm2, pulse number 328, scanning spacing 80?m can reach the maximum, and the maximum contact angle of titanium alloy and composites were 148.55° and 148.7° respectively.(4) The results of research on testing performance of hydrophobic coating show that the coating with low surface energy have strong bonding force.When interacting with the micro-nano structure, coatings can effectively reduce the adhesion of ice, and it has better ability of resistance to kerosene, water and heat shock etc..