scholarly journals Robust nanosecond laser passively Q-switched by tin selenide nanoflowers

2021 ◽  
Author(s):  
Qian Yi ◽  
Lingling Yang ◽  
Ke Yang ◽  
Jie Li ◽  
Lin Du ◽  
...  
Keyword(s):  
Nanosecond Laser ◽  
Tin Selenide

Nanosecond laser-induced breakdown assisted by femtosecond laser pre-ionization in air: the effect on spatial resolution and continuous radiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20701
Author(s):  
Bo Li ◽  
Xiaofeng Li ◽  
Zhifeng Zhu ◽  
Qiang Gao
Keyword(s):  
Femtosecond Laser ◽  
Spatial Resolution ◽  
Laser Induced Breakdown Spectroscopy ◽  
Nanosecond Laser ◽  
Breakdown Threshold ◽  
Powerful Technique ◽  
Breakdown Spectroscopy ◽  
Continuous Radiation ◽  
Laser Induced Breakdown

Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.

scholarly journals Investigation of Multiparameter Laser Stripping of AlTiN and DLC C Coatings

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 951
Author(s):  
Tomáš Primus ◽  
Josef Hlavinka ◽  
Pavel Zeman ◽  
Jan Brajer ◽  
Martin Šorm ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Efficiency ◽  
Steel Substrate ◽  
Cutting Tools ◽  
High Hardness ◽  
Working Time ◽  
Nanosecond Laser ◽  
Altin Coating ◽  
Successful Removal ◽  
Frequency Laser

The lifetime and properties of cutting tools and forming moulds can be prolonged and enhanced by the deposition of hard, thin coatings. After a certain period of usage, the coating will deteriorate. Any remaining coating must be removed prior to successful recoating. Laser stripping is a fast and environmentally friendly coating removal method. In this paper, we present laser removal of two types of coatings deposited on a 1.2379 tool steel substrate, namely, an AlTiN coating with high hardness and a DLC C coating with a small coefficient of friction (COF). A powerful nanosecond laser was employed to remove the coating from the substrate with high efficiency, along with suitable residual surface roughness. Measurements were taken of surface roughness, removed depth, and working time on a stripped area of 1 cm2. The samples were evaluated under a microscope, with a 3D profilometer, and by EDS chemical analysis. Successful removal of the coating was confirmed by optical analysis, but detailed chemical characterisation showed that about 30% of the coating element may remain on the surface. Moreover, a working time of less than 7.5 s per cm2 was obtained in this study. In addition, it was shown that the application of a second low energy, high frequency laser beam pass leads to remelting of the peaks of the material and reduced surface roughness.

Nanosecond laser cleaning for enhanced zinc coating quality of HSLA steel

2021 ◽  
Vol 143 ◽  
pp. 107311
Author(s):  
Lixin Zhu ◽  
Qing Gao ◽  
Bingtao Sun ◽  
Yongjun Ke ◽  
Yang Tan ◽  
...  
Keyword(s):  
Hsla Steel ◽  
Zinc Coating ◽  
Laser Cleaning ◽  
Nanosecond Laser ◽  
Coating Quality

scholarly journals Surface Forming Criteria of Ti-6AL-4V Titanium Alloy under Laser Loading

2021 ◽  
Vol 11 (12) ◽  
pp. 5406
Author(s):  
Fei Yin ◽  
Xia Ye ◽  
Hongbing Yao ◽  
Pengyu Wei ◽  
Xumei Wang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Surface Morphology ◽  
High Speed ◽  
Yttrium Aluminum Garnet ◽  
Laser Energy ◽  
Target Material ◽  
Nanosecond Laser ◽  
Laser Shock ◽  
Shock Condition ◽  
Key Factor

In order to study the spallation phenomenon of titanium alloy under the shock of nanosecond laser, the Neodymium-Yttrium-Aluminum Garnet laser was used to carry out laser shock experiments on the surface of titanium alloy. By observing and measuring the surface morphology of the target material, the forming factors and the changes of the surface morphology under different parameter settings, the forming criteria of the titanium alloy were obtained. The results show that under the single variable method, the change of laser energy can affect the target shape variable, and there is a positive correlation between them. When the thickness was greater than or equal to 0.08 mm, no obvious cracks were found in the targets. Moreover, the number of impact times was the key factor for the target deformation; with the growth of impact times, the target deformation gradually became larger until the crack appeared. The larger the diameter of the spot, the more likely the target was to undergo plastic deformation. The surface of titanium alloy with a thickness of 0.08 mm appeared to rebound under specific laser shock condition. The changes in the back of the target material were observed in real time through a high-speed camera, and the plasma induced by the laser was observed in the process. This study is based on the results of previous studies to obtain the titanium alloy forming criteria, which provides a basis for the setting of laser parameters and the thickness of the target when the nanosecond laser impacts the Ti-6AL-4V target.

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