| 摘要: |
| 在远程管道运输过程中，固液间摩擦阻力是一个不容忽视的问题，类鲨鱼结构减阻效率低且制备困难。基于荷叶表面仿生思想，构筑微结构制备超疏水表面，减小摩擦阻力。采用飞秒激光刻蚀与电沉积复合工艺，在不锈钢表面构筑框-锥多级结构，经自组装氟硅烷制备超疏水表面，讨论复合工艺参数对微结构形貌及润湿性能的影响，探究框-锥多级结构超疏水表面减阻。结果表明，利用飞秒激光可获得周期性分布的框结构，随着激光功率的增加，微米框结构内部形成不规则沟壑金属堆积物，且关光延时的增长会产生单侧分布微孔结构，损伤基体整体强度；通过电沉积工艺制备亚微米尖锥结构镍镀层，随着电流密度的增加，镀层微结构形态发生变化，形成亚微米尖锥石结构，表面由疏水转变为超疏水。与激光刻蚀 10 次自组装氟硅烷涂层试样相比，激光刻蚀与电沉积复合工艺自组装氟硅烷涂层的试样表面接触角由 138.6°提高到 156.7°，对水和 30 wt.%甘油的减阻率分别由 8.17%、14.38%提高到 27.74%、23.69%。将激光刻蚀与电沉积相结合，构筑微纳结构经自组装制备超疏水表面，可为降低管道输运中固液间摩擦阻力提供新的技术途径。 |
| 关键词: 管道运输 复合工艺 超疏水 框-锥多级结构 减阻 |
| DOI：10.11933/j.issn.1007?9289.20221015001 |
| 分类号:TG174 |
| 基金项目:国家自然科学基金（52175207）；国防科技领域基金（2020-JCJQ-JJ-378）资助项目 |
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| Combined Femtosecond Laser and Electrodeposition Process to Prepare Stainless-steel Superhydrophobic Surfaces with Reduced Drag |
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LIU Hao1,2, ZHAO Yuncai1, DI Yuelan2, WANG Haidou3, HUANG Yanfei2
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1.School of Mechatronics Engineering, Jiangxi University of Science and Technology, Ganzhou 341000 , China;2.National Key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072 , China;3.National Engineering Research Center for Remanufacturing, Army Academy of Armored Forces,Beijing 100072 , China
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| Abstract: |
| In long-distance pipeline transportation, the relative motion of the solid and liquid phases generates a large frictional drag between them, which is a problem that cannot be ignored. The shark-like ribbed groove microstructure, commonly used to reduce resistance, has poor drag-reduction stability, low efficiency, and is difficult to prepare. Therefore, based on the bionic concept, microstructures were constructed and modified through self-assembly to produce superhydrophobic surfaces that reduce the frictional drag between the solid and liquid phases. A superhydrophobic surface was constructed on the surface of 3Cr13 stainless steel using a composite process of femtosecond laser etching and electrodeposition, and the surface was modified using a self-assembled fluorosilane coating. The effects of the laser etching and electrodeposition parameters on the morphology and surface wettability of the frame-cone multilevel microstructures were analyzed. Additionally, the drag reduction performance of the superhydrophobic surface of the frame-cone multilevel structure was investigated underwater. The results showed that periodically distributed micron frame structures can be obtained using a femtosecond laser, with an irregularly grooved metal build-up forming inside the micron frame structure as the laser power increases. An increase in the off-light delay produces a unilateral regular distribution of microporous structures, which damages the overall strength of the substrate. At 35% laser power and 180 μs off delay, the micron frame structure was constructed with an intact surface. Moreover, the depth of the micron frame structure increased linearly with the number of femtosecond laser etchings. When the laser etching was conducted 10 times, the frame structure depth and the static contact angle of the surface were 4.23 μm and 138.6°, respectively. The nano/submicron cone structure of the nickel coating was prepared using electrodeposition, and both the current density and deposition time affected the microstructure morphology of the nickel coating. With an increase in the current density and deposition time, the surface microstructure of the nickel coatings changed from small to large cones and finally to a broad leaf-like structure. The surface of the microstructure was transformed from hydrophobic to superhydrophobic using a self-assembled fluorosilane coating. The optimum electrodeposition process parameters were a current density of 3 A/dm2 and a deposition time of 10 min, where the percentage of 800–1200 nm cones was 72.5%, and the static contact angle of the surface was 158.73° Compared with the conventional micro-nano needle cone structure, the superhydrophobic surface of the micro-nano frame-cone multilevel structure prepared using the laser etching and electrodeposition composite process enhanced the boundary slip effect and improved the underwater drag-reduction performance. Compared with the 10-times laser-etched self-assembled fluorosilane-coated samples, the contact angle of the self-assembled fluorosilane-coated samples prepared using combined laser etching and electrodeposition increased from 138.6° to 156.7°, and the drag reduction rates for water and 30 wt.% glycerol increased from 8.17% and 14.38% to 27.74% and 23.69%, respectively. The superhydrophobic surface was prepared using combined laser etching and electrodeposition to construct micro-and nanostructures using self-assembly, providing a new technical method of reducing the frictional resistance between solid and liquid phases in pipeline transportation; however, its preparation technology is more demanding. |
| Key words: pipeline transportation combined process superhydrophobic frame-cone multilevel structure drag reduction |
