摘要
目的分析不同激光参数对飞秒激光在碳纤维增强复合材料(CFRP)表面制备微结构的影响和不同微结构参数对CFRP表面疏水性的影响,为CFRP自清洁表面以及表面防腐蚀保护提供参考。方法使用飞秒激光微加工系统在CFRP表面制备出网格状微结构,依次调节不同的激光功率、标刻速度、标刻次数、激光频率,通过超景深显微镜对微结构形貌进行分析和表征,分析单个激光参数变化对微结构尺寸及形状的影响。通过四因素五水平的正交试验分析出激光参数对微结构影响的主次,确定了最优组合加工方案。最后对不同尺寸的微结构表面使用接触角测量仪进行材料表面润湿性分析。结果当激光功率为1.6W、标刻速度为250 mm/s、标刻次数为6次、激光频率为100 kHz、扫描间距为30μm时,可加工出高度为36.17μm、深宽比为3.56、周期间距为1.81的网格状微结构,此时CFRP表面接触角为161.21°达到超疏水状态。结论激光参数对微结构形貌及尺寸影响的主次顺序为:标刻速度影响最大,激光功率和扫描次数影响次之,激光频率影响最小。网格状微结构的周期间距临界值为1.95、微结构深宽比大于1.76,可使液滴在材料表面处于稳定的Cassie-Baxter状态。
Femtosecond laser processing of micro-nanostructures represents an advanced and effective method for fabricating superhydrophobic surfaces.Its advantage lies in the precise control of the microstructures on the material surface,enabling fine-tuned manipulation of surface wettability.The work aims to analyze the effect of different laser parameters on the formation of microstructures on carbon fiber-reinforced polymer(CFRP)surfaces with femtosecond laser technology,and explore the impact of various microstructural parameters on the surface hydrophobicity of CFRP.This provides valuable insights for the development of self-cleaning and corrosion-resistant CFRP surfaces.Grid-like microstructures were created on the CFRP surface with a femtosecond laser micromachining system.The process involved sequentially adjusting various laser parameters,including laser power,marking speed,number of marking passes,and laser frequency,to process the CFRP surface.After processing,the morphology of the microstructures was analyzed and characterized with an ultra-depth-of-field microscope(VHX-6000).This analysis aimed to determine the effect of individual laser parameter variations on the dimensions and shapes of the microstructures.An orthogonal experiment with four factors at five levels was conducted to prioritize the effect of laser parameters on the microstructures,leading to the identification of the optimal combination of processing parameters.Finally,the wettability of the material surfaces with different microstructures was analyzed with a contact angle measuring instrument.The results revealed a positive correlation between laser power and laser spot diameter.When the laser power exceeded 1.7 W,the processing width increased,accompanied by damage to the microstructure morphology.The marking speed affected the processing depth,with a decrease in speed,resulting in an increase in depth.However,at the speed below 100 mm/s,the microstructure morphology was damaged due to ablation,while at the speed above 250 mm/s,the processing depth was too shallow.When the number of marking passes exceeded six,overall ablation and gasification of the structure occurred,while fewer than two passes resulted in insufficient processing depth.An increase in laser frequency led to an increase in processing depth,but when the frequency surpassed 200 kHz,the top of the structure was ablated and gasified,flattening the processed surface and reducing its roughness.Through the orthogonal experiment,the primary and secondary impacts of processing parameters on microstructures were determined.For microstructural periodic spacing,the marking speed had the most significant impact,followed by laser power and the number of scanning passes,with laser frequency having the least impact.Similarly,the marking speed had the greatest impact on the aspect ratio of microstructures,followed by the number of scanning passes and laser power,with laser frequency again having the least impact.By adjusting laser parameters,the microstructures with varying periodic spacing and aspect ratios were prepared,and the contact angles of each microstructured surface were measured.The contact angle values for different periodic spacing were fitted with a Gauss function,revealing an approximate Gaussian distribution between 0.75 and 2.85 microns of periodic spacing,with a maximum value at 1.95 microns.For different aspect ratios ranging from 0.61 to 3.56,a polynomial function was used for nonlinear curve fitting.The results showed that as the aspect ratio increased,the contact angle gradually increased,reaching a maximum at 3.56.With the optimal parameters obtained from the fitting results,the processed CFRP surface achieved a static contact angle of 162.21°,demonstrating excellent hydrophobic properties.The conclusion indicates that for the liquid droplets to remain in a stable Cassie-Baxter state on the material surface,the periodic spacing of the microstructures should be less than the critical spacing of 1.95 microns,and the aspect ratio should exceed the critical value of 1.76.Within this range of structural parameters,effectively enhancing the contact angle between droplets and the material surface,thereby achieving superhydrophobicity,can be accomplished by increasing the processing width to reduce the side length of the pillars and increasing the processing depth.Specifically,under conditions of 1.6 W laser power,250 mm/s marking speed,six marking passes,100 kHz laser frequency,and 30μm scanning spacing,grid-like microstructures with a height of 36.17μm,an aspect ratio of 3.56,and a periodic spacing of 1.81 microns are fabricated,resulting in a superhydrophobic CFRP surface with a contact angle of 162.21°.
作者
李金龙
关会英
马晓旺
李玲玉
LI Jinlong;GUAN Huiying;MA Xiaowang;LI Lingyu(College of Mechanical and Electrical Engineering,Jilin University of Chemical Technology,Jilin Jilin 132022,China)
出处
《表面技术》
北大核心
2025年第12期217-228,共12页
Surface Technology
基金
国家自然科学基金(51805207)。
关键词
碳纤维增强复合材料
飞秒激光
润湿性
表面微结构
接触角
超疏水
carbon fiber reinforced polymer
femtosecond laser
wettability
surface microstructure
contact angle
superhydrophobicity
