scholarly journals Layer-by-Layer Repair of Small-Scale Damage of Fused Silica Based on the Magnetorheological Method

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1233
Author(s):  
Mingjie Deng ◽  
Ci Song ◽  
Feng Shi ◽  
Wanli Zhang ◽  
Ye Tian ◽  
...  

The magnetorheological (MR) repair method can effectively repair the small-scale damage of fused silica optics and further improve the laser-induced damage threshold of fused silica optics. However, at present, the rules of MR repair of small-scale damage of fused silica are not clear and cannot provide further guidance for the repair process. In this paper, the fused silica damage samples were repaired layer by layer by the MR method. The number and size changes of all the surface damage, the morphology, the fluorescence area distribution, and photothermal-absorption value of a single typical small-scale damage were measured. Through dark field scattering imaging, it is found that when the repair depth is 5 μm, the repair completion rate of damage with a transverse size less than 50 μm can reach 44%, and the repair efficiency decreases gradually with the repair process. Focusing on the whole repair process of a single typical, small-scale damage—due to the flexible shear removal mechanism of the MR method—the repair process of damage can be divided into three stages, which as a whole is a top-down, from outside to inside process. The first stage is the process of removing the surface of the damage layer by layer. In this process, MR fluid will introduce pollution to the inside of the damage. In the second stage, MR fluid begins to repair the inside of the damage. In the third stage, the MR ribbon completely covers the inside of the damage, and the repair effect is the most obvious. The measurement results of photothermal absorption and fluorescence area distribution of damage confirm this process. The photothermal absorption value and fluorescence area distribution of damage do not simply decrease with the repair process. On the contrary, they gradually increase first, and then decrease significantly when the damage depth reaches less than 1 μm. As the thickness of the MR ribbon is 1 μm, the reduction in the photothermal absorption value and fluorescence area of the damage is due to the process of repairing the inside of the damage. The results show that the absorbent impurities inside the small-scale damage of fused silica are the main factor affecting the performance. The key to repairing the small-scale damage of fused silica by the MR method is that the damaged interior must be repaired effectively. This paper outlines the MR repair method of small-scale damage of fused silica, which is of great significance to optimize the MR repair process.

Author(s):  
Yajing Guo ◽  
Shunxing Tang ◽  
Xiuqing Jiang ◽  
Yujie Peng ◽  
Baoqiang Zhu ◽  
...  

Abstract An effective damage test method based on a marker-based watershed algorithm with gray control (MWGC) is proposed to study the properties of damage induced by near-field laser irradiation for large-aperture laser facilities. Damage tests were performed on fused silica samples and information on the size of damage sites was obtained by this new algorithm, which can effectively suppress the issue of over-segmentation of images resulting from non-uniform illumination in dark-field imaging. Experimental analysis and results show that the lateral damage growth on the exit surface is exponential, and the number of damage sites decreases sharply with damage site size in the damage site distribution statistics. The average damage growth coefficients fitted according to the experimental results for Corning-7980 and Heraeus-Suprasil 312 samples at 351 nm are $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}1.10 \pm 0.31$ and $0.60 \pm 0.09$ , respectively.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 274
Author(s):  
Mingjie Deng ◽  
Ci Song ◽  
Feng Shi ◽  
Yaofei Zhang ◽  
Ye Tian ◽  
...  

The damage repair of fused silica based on the CO2 laser repair technique has been successfully applied in high-power laser systems in the controllable nuclear fusion field. However, this kind of repairing technique mainly focuses on large-scale laser damage with sizes larger than 200 μm, but ignores the influence of cluster small-scale damage with sizes smaller than 50 μm. In order to inhibit the growth of small-scale damage and further improve the effect of fused silica damage repair, this paper carried out a study on the repair of fused silica damage using the magnetorheological (MR) removing method. The feasibility of fused silica damage repairing was verified, and the evolution law of the number, morphology, and the surface roughness of small-scale damage were all analyzed. The results showed that the MR removing method was non-destructive compared to traditional repairing technologies. It not only effectively improved the whole damage repairing rate to more than 90%, but it also restored the optical properties and surface roughness of the damaged components in the repairing process. Based on the study of the MR removing repair law, a combined repairing process of 4 μm MR removal and 700 nm computer controlled optical surfacing (CCOS) removal is proposed. A typical fused silica element was experimentally repaired to verify the process parameters. The repairing rate of small-scale damage was up to 90.4%, and the surface roughness was restored to the level before repairing. The experimental results validate the effectiveness and feasibility of the combined repairing process. This work provides an effective method for the small-scale damage repairing of fused silica components.


2020 ◽  
Vol 508 ◽  
pp. 145186
Author(s):  
Bo Li ◽  
Chunyuan Hou ◽  
Chengxiang Tian ◽  
Jianlei Guo ◽  
Xia Xiang ◽  
...  

1998 ◽  
Author(s):  
Alberto Salleo ◽  
Francois Y. Genin ◽  
J. M. Yoshiyama ◽  
Christopher J. Stolz ◽  
Mark R. Kozlowski

2017 ◽  
Vol 25 (23) ◽  
pp. 29260 ◽  
Author(s):  
Mingjin Xu ◽  
Feng Shi ◽  
Lin Zhou ◽  
Yifan Dai ◽  
Xiaoqiang Peng ◽  
...  

2009 ◽  
Vol 29 (3) ◽  
pp. 756-760 ◽  
Author(s):  
唐顺兴 Tang Shunxing ◽  
欧阳小平 Ouyang Xiaoping ◽  
朱宝强 Zhu Baoqiang ◽  
林尊琪 Lin Zunqi

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