Wöbbeking Karl, Li Mingji, Hübner Eike G, Schade Wolfgang
Fraunhofer Heinrich Hertz Institute, Department Fiber Optical Sensor Systems Am Stollen 19H DE-38640 Goslar Germany.
Clausthal University of Technology, Institute of Organic Chemistry Leibnizstr. 6 DE-38678 Clausthal-Zellerfeld Germany
RSC Adv. 2019 Nov 19;9(64):37598-37607. doi: 10.1039/c9ra05918k. eCollection 2019 Nov 13.
Femtosecond laser micromachining is an important and flexible method to generate precisely targeted surfaces on various materials. On titanium, the laser structuring process strongly depends on the laser parameters. For example, an increasement of the pulse length and repetition rate favors melting processes instead of ablation and microstructuring. We report on an investigation of reactive halogens (iodine, bromine, chlorine) and halocarbons as additives to the laser structuring process of pure titanium and the common alloy Ti-6Al-4V with 0.75 ps laser pulses. The choice of the halogen allows control of whether solely the chemical composition or the surface microstructure should be altered. Bromine was found to be an efficient additive to generate homogeneous microstructures based on micropillars at convenient conditions (air, atmospheric pressure). The resulting surfaces have been characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy, thermal emission infrared photography, reflective UV/Vis spectroscopy and contact angle measurements. The bromine/air processed titanium surfaces revealed superhydrophilicity, strongly increased thermal emissivity and a high absorptivity ("black metal").
飞秒激光微加工是一种在各种材料上生成精确靶向表面的重要且灵活的方法。在钛材料上，激光结构化过程强烈依赖于激光参数。例如，脉冲长度和重复率的增加有利于熔化过程而非烧蚀和微结构化。我们报告了一项关于将活性卤素（碘、溴、氯）和卤代烃作为添加剂用于纯钛和常见合金Ti-6Al-4V的激光结构化过程的研究，该过程采用0.75皮秒激光脉冲。卤素的选择可以控制是仅改变化学成分还是改变表面微观结构。研究发现，溴是一种有效的添加剂，可在适宜条件（空气、大气压）下基于微柱生成均匀的微观结构。通过扫描电子显微镜、能量色散X射线光谱、热发射红外摄影、反射紫外/可见光谱和接触角测量对所得表面进行了表征。经溴/空气处理的钛表面呈现出超亲水性、显著提高的热发射率和高吸收率（“黑色金属”）。
