Zheng Qingzhen, Fan Zhengjie, Jiang Gedong, Pan Aifei, Yan Zhaoxuan, Lin Qingyan, Cui Jianlei, Wang Wenjun, Mei Xuesong
Opt Express. 2019 Sep 16;27(19):26264-26280. doi: 10.1364/OE.27.026264.
Silicon carbide (SiC) ceramics have been widely used for microelectronics, aerospace, and other industrial fields due to their excellent chemical stability and thermal tolerance. However, hard machinability and low machining precision of SiC ceramics are the key limitations for their further applications. To address this issue, a novel method of underwater femtosecond laser machining was introduced in this study to obtain high precision and smooth surface of the microgrooves of SiC ceramics. The removal profiles were characterized in terms of width, depth, and surface morphology, which exhibited high dependence on the femtosecond laser processing parameters. The instability during the underwater processing affected by laser-induced gas bubbles and material deposition, however, limits the high surface accuracy of microgrooves and processing efficiency. The process condition transformation from a bubble-disturbed circumstance to a disturbance-free model was carefully investigated through a high speed camera for the femtosecond laser processing of SiC ceramics in water. The experiment results indicated that degree of disturbed effect was heavily dependent on size, distribution, and motion of laser-induced gas bubble. Furthermore, some typical evolution mechanisms of gas bubble and their influence on the removal profiles of microgrooves were discussed in detail. Bubble evolution has been proven to be mainly responsible for the behavior of laser propagation (focus model, total reflection, etc.), which notably affects microstructural characteristic of the microgrooves.
碳化硅（SiC）陶瓷因其优异的化学稳定性和耐热性而被广泛应用于微电子、航空航天等工业领域。然而，SiC陶瓷的难加工性和低加工精度是其进一步应用的关键限制因素。为了解决这一问题，本研究引入了一种新颖的水下飞秒激光加工方法，以获得高精度且表面光滑的SiC陶瓷微槽。通过宽度、深度和表面形貌对去除轮廓进行了表征，其对飞秒激光加工参数具有高度依赖性。然而，水下加工过程中受激光诱导气泡和材料沉积影响的不稳定性限制了微槽的高表面精度和加工效率。通过高速摄像机对水中SiC陶瓷的飞秒激光加工过程进行了仔细研究，以实现从气泡干扰环境到无干扰模型的工艺条件转变。实验结果表明，干扰效果的程度在很大程度上取决于激光诱导气泡的大小、分布和运动。此外，还详细讨论了气泡的一些典型演化机制及其对微槽去除轮廓的影响。气泡演化已被证明主要影响激光传播行为（聚焦模型、全反射等），这对微槽的微观结构特征有显著影响。
