Study On Wettability Of Fused Silica Surface Modified By Femtosecond Laser

Fused silica has excellent optical,mechanical and chemical properties.It is widely used to prepare the packaging shell of optical fiber probe,micro gyroscope and other components.However,due to the poor wettability of fused silica,the package temperature is high and the service life of the device is reduced.In this paper,a method of adjusting the wettability of fused silica surface based on femtosecond laser surface modification is proposed.By adjusting the surface morphology of fused quartz,improving its wettability,reducing the packaging temperature,and improving the service life of the encapsulated device.Combined with numerical calculation and experimental analysis,the influence of femtosecond laser processing parameters on the surface morphology of fused silica is studied,and the formation mechanism of laser-induced surface periodic structure(LIPSS)under high-speed scanning of femtosecond laser is clarified.On this basis,the multi-stage micro nano structure was prepared on the surface of fused quartz,and the influence of micro nano structure on wettability was studied.The main research contents and conclusions are as follows:Firstly,the LIPSS's process window and the formation mechanism of LIPSS during high-speed scanning(1000 mm/s)are studied.The relationship between the formation of LIPSS under high-speed scanning and single point processing is established by numerical calculation using temperature,and the micro nano structure mechanism of fused silica surface induced by femtosecond laser high-speed scanning is clarified.The results show that the nanoscale LIPSS is easier to form for lower input power when scanning at a high speed of1000 mm/s.Then on the basis of the above,femtosecond laser was used to prepare the multi-stage micro nano structure based on nano LIPSS and micro wire slot.The influence of multi-stage micro nano structure on water wettability and the mechanism of surface wettability improvement were studied.It was concluded that the change of surface area was the basic reason of the surface wettability of multi-stage micro nano structure.When the array spacing of multi-stage micro nano structure is too small,the remelting effect of post processing groove on the pre processing groove reduces the interface expansion area and the surface wettability.Using two-way array can greatly improve the interface expansion area,and then improve the wettability of water.Finally,the best array parameters of wettability are array spacing 20?m,orthogonal array.Lastly,in order to verify the effectiveness of the multi-stage micro nano structure modified on the fused silica surface to reduce the packaging temperature,the wetting spread of(Ag₇₂Cu₂₈)₉₇Ti₃(wt.%)solder at different temperatures before and after the modification was measured by high temperature wetting test.It was found that the wettability of the solder on the modified fused silica surface was greatly improved.When the heating temperature is the same,the wetting angle is 12°lower than that of unmodified fused silica glass;when the wetting angle is the same,the heating temperature is 22?.The wetting spreading mechanism of the solder on the unmodified and multi-stage micro nano structure modified fused silica was studied by detecting the chemical composition of micro nano structure and the interface after wetting spreading.