Schnell Georg, Duenow Ulrike, Seitz Hermann
Microfluidics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Justus-von-Liebig-Weg 6, 18059 Rostock, Germany.
Department Life, Light & Matter, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany.
Materials (Basel). 2020 Feb 21;13(4):969. doi: 10.3390/ma13040969.
Surface structuring is a key factor for the tailoring of proper cell attachment and the improvement of the bone-implant interface anchorage. Femtosecond laser machining is especially suited to the structuring of implants due to the possibility of creating surfaces with a wide variety of nano- and microstructures. To achieve a desired surface topography, different laser structuring parameters can be adjusted. The scanning strategy, or rather the laser pulse overlap and scanning line overlap, affect the surface topography in an essential way, which is demonstrated in this study. Ti6Al4V samples were structured using a 300 fs laser source with a wavelength of 1030 nm. Laser pulse overlap and scanning line overlap were varied between 40% and 90% over a wide range of fluences ( from 0.49 to 12.28 J/cm²), respectively. Four different main types of surface structures were obtained depending on the applied laser parameters: femtosecond laser-induced periodic surface structures (FLIPSS), micrometric ripples (MR), micro-craters, and pillared microstructures. It could also be demonstrated that the exceedance of the strong ablation threshold of Ti6Al4V strongly depends on the scanning strategy. The formation of microstructures can be achieved at lower levels of laser pulse overlap compared to the corresponding value of scanning line overlap due to higher heat accumulation in the irradiated area during laser machining.
表面结构化是定制合适的细胞附着以及改善骨-植入物界面锚固的关键因素。飞秒激光加工特别适合于植入物的结构化，因为它能够制造出具有各种纳米和微结构的表面。为了实现所需的表面形貌，可以调整不同的激光结构化参数。扫描策略，或者更确切地说是激光脉冲重叠和扫描线重叠，对表面形貌有着至关重要的影响，本研究对此进行了论证。使用波长为1030 nm的300 fs激光源对Ti6Al4V样品进行结构化处理。在很宽的能量密度范围（从0.49到12.28 J/cm²）内，激光脉冲重叠和扫描线重叠分别在40%到90%之间变化。根据所应用的激光参数，获得了四种不同的主要表面结构类型：飞秒激光诱导的周期性表面结构（FLIPSS）、微米级波纹（MR）、微坑和柱状微结构。还可以证明，Ti6Al4V的强烧蚀阈值的超逾强烈依赖于扫描策略。由于激光加工过程中被辐照区域的热量积累更高，与扫描线重叠的相应值相比，在较低的激光脉冲重叠水平下就能实现微结构的形成。
