| WU Dongjiang,LIU Cheng,YANG Feng,NIU Fangyong,DONG Zhigang,MA Guangyi,KANG Renke.Effect of Femtosecond Laser Processing Parameters on RB-SiC Surface Morphology[J],53(3):162-169 |
| Effect of Femtosecond Laser Processing Parameters on RB-SiC Surface Morphology |
| Received:January 12, 2023 Revised:October 06, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.03.016 |
| KeyWord:femtosecond laser RB-SiC ablation groove surface morphology laser energy density number of effective pulses |
| Author | Institution |
| WU Dongjiang |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| LIU Cheng |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| YANG Feng |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| NIU Fangyong |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| DONG Zhigang |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| MA Guangyi |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
| KANG Renke |
School of Mechanical Engineering, Dalian University of Technology, Liaoning Dalian , China |
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| Abstract: |
| The work aims to reveal the effect of femtosecond laser processing parameters on the surface morphology of reaction-bounded silicon carbide(RB-SiC). RB-SiC was cut into a sample of 30 mm×20 mm×3 mm, and then the surface was cleaned and polished with diamond abrasive paper. During the experiment, by femtosecond laser micromachining system and HR-Femo-IR-200-40 fiber femtosecond laser, grooves were processed on the surface of RB-SiC by changing the laser energy density and effective pulse number. The moving speed of the laser beam was 40 mm/s, the repetition frequency of the laser pulse was 200 kHz, and the focal length was 70 mm. The surface morphology of RB-SiC before and after ablation was observed by field emission scanning electron microscope, the change rule of RB-SiC surface ablation morphology was clarified, and the material removal mechanism of femtosecond laser processing RB-SiC was determined. The width and depth of the groove were measured by the laser confocal microscope, and the data obtained were fitted and analyzed by the least square method. The element distribution and material changes in RB-SiC micro-area before and after ablation were analyzed by X-ray energy spectrometer and DXR Raman spectrometer. The initial surface morphology of RB-SiC could be divided into two areas:the Si enriched area composed of 3C-SiC and Si, and the SiC particle area composed of 6H-SiC. When the laser energy density was in the range of 0.62-10.48 J/cm2, the molten Si and 3C-SiC in the Si enriched area would be removed and then a concave structure would be formed. The SiC particle area would be ablated to form a laser-induced periodic surface structures (LIPSS) with a period of about 970 nm, which was generated by the interference of laser beam and plasma wave. Due to the condensation and adhesion of silicon vapor, the silicon content on the processed SiC surface was relatively high. With the increase of laser energy density, the concave structure expanded and deepened, a large number of oxygen-containing spherical nanoparticles were produced on the ablated surface, the SiC was decomposed to form a new carbon substance, and the width of the ablated groove increased logarithmically. When the effective pulse number was in the range of 69-1 379, the removal depth between the two areas was different, and the removal depth of the Si enriched area was always higher than that in the SiC particle area. With the increase of effective pulse number, the depth of the ablation groove increased significantly, the concave structure further expanded into a deep pit structure, the nano-particles splashed to the outside of the ablation groove to form clusters, and the deposits composed of Si, SiC and amorphous SiO2 formed an accumulation layer at the edge of the ablation groove. The results show that reducing the laser energy density can reduce the surface concave structure and nano-particles of RB-SiC, which is helpful to improve the consistency of ablation morphology. Increasing the number of effective pulses will promote the generation of deep pit structure at the bottom of the ablation groove and then the difference between Si and SiC removal will be expanded. |
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