基于飞秒激光表面修饰的石英玻璃润湿性分析

采用飞秒激光高速扫描的方法对熔石英表面进行多级微纳结构制备，其中一级结构为周期性微纳条纹结构，二级结构为蚀刻沟槽，三级结构为沟槽交叉形成的阵列结构. 通过数值计算分析了飞秒激光高速扫描下熔石英的烧蚀阈值，揭示了高速飞秒激光诱导熔石英表面微纳结构的机理. 对修饰后的熔石英微观形貌观察和润湿性试验表明，当飞秒激光重复频率1 MHz，扫描速度1 000 mm/s，55%峰值功率时，熔石英表面沟槽间距为30 μm的正交阵列具有最优的润湿性. 与未处理的熔石英相比，Bi₂O₃-50%B₂O₃ (质量分数，%)钎料在修饰后熔石英表面的润湿角降低了8°，有效改善了熔石英玻璃的钎焊能力.

Analysis on the wettability of fused silica glass surface modified by femtosecond Laser

A femtosecond laser high-speed scanning method is used to prepare hierarchical micro-nano structures on the surface of fused silica. One-scale is periodic micro-nano structure, two-scale is the ablation groove and triple-scale is the gridding structure comprised by bi-direction grooves. The mechanism of micro-nano structure fabricated by femtosecond laser scanning at high speed was revealed through numerical calculations. The wettability test shows that micro-nano structure with the period of 400～500nm which obtained under 1 MHz, 1 000 mm/s, 55% peak power and 30 μm the orthogonal groove spacing has the best wettability. The contact angle of Bi₂O₃-50%B₂O₃ solder can be reduced by 8° than that of unmodified fused silica which is beneficial to reduce the residual stress of the brazed joint.