光学学报, 2017, 37 (4): 0414001, 网络出版: 2017-04-10
单脉冲激光烧蚀青铜砂轮等离子体物理模型研究
Research of Plasma Physical Model for Single Pulsed Laser Ablation of Bronze-Bond Grinding Wheel
激光技术 激光烧蚀 等离子体 光谱特性 物理模型 laser technique laser ablation plasma spectral characteristic physical model
摘要
采用光栅光谱仪测量了单脉冲激光烧蚀青铜金刚石砂轮的等离子体空间分辨发射光谱,计算得到单脉冲激光烧蚀下等离子体电子温度约为5220 K,距离砂轮表面0~0.35 mm范围内等离子体电子密度值为0.5×1016~1.8×1016 cm-3。建立了单脉冲激光烧蚀青铜金刚石砂轮的等离子体浓度空间分布模型以及等温膨胀动力学方程,仿真结果表明,在一个脉冲时间内,等离子体等温膨胀速度最大值出现在25 ns左右,等离子体浓度最大值(1.8943×1016 cm-3)出现在距离砂轮表面0.05 mm处,且等离子体屏蔽作用小,实际烧蚀中可以不予考虑。试验结果与数值仿真结果数量级基本一致,验证了等离子体物理模型的正确性。研究结果对优化脉冲激光烧蚀工艺具有指导作用。
Abstract
The grating spectrometer is used to measure the spatially resolved emission spectrum of plasma in single pulsed laser ablation of bronze-bonded diamond grinding wheel. The electronic temperature of plasma in single pulsed laser ablation is 5220 K by calculation. The electron density is about 0.5×1016-1.8×1016 cm-3 at the range of 0-0.35 mm away from the grinding wheel surface. The spatial distribution model of plasma concentration and the dynamic equation of isothermal expansion are built. The simulation results show that the maximum isothermal expansion speed of plasma appears approximately at 25 ns during the single pulse time. The maximum plasma concentration of 1.8943×1016 cm-3 appears at 0.05 mm away from the grinding wheel surface, and the plasma shielding effect is so small that it can be ignored in the actual process. The experimental results have the same order of magnitude with the numerical simulation results, which verifies the correctness of the plasma physical model. The research results offer guidance to the optimization of pulsed laser ablation process.
蔡颂, 陈根余, 周聪, 明兴祖. 单脉冲激光烧蚀青铜砂轮等离子体物理模型研究[J]. 光学学报, 2017, 37(4): 0414001. Cai Song, Chen Genyu, Zhou Cong, Ming Xingzu. Research of Plasma Physical Model for Single Pulsed Laser Ablation of Bronze-Bond Grinding Wheel[J]. Acta Optica Sinica, 2017, 37(4): 0414001.