大气感耦射流等离子体加工中的电子温度及激发光谱研究

大气感耦射流等离子体加工作为新型超光滑表面加工技术，其高密度等离子体激发能力为充分激发反应气体，提高材料去除率提供了有力条件。利用发射光谱仪，对加工过程中大气感耦射流等离子体激发的400~1 000 nm范围内的光谱进行了测量。并利用峰值明显，能级差较大的谱线计算电子温度。由于测量的谱线强度是等离子体发射系数沿弧长方向的积分值，且感耦射流等离子体具有回转对称性，因此可利用阿贝尔变换求取光谱发射系数，进而通过玻尔兹曼图谱法计算电子温度。计算结果表明由于趋肤效应和旋流进气的双重作用，处于加工区域的温度分布呈现出双峰形;随着距离增大，双峰效应逐渐减弱，温度分布趋于平滑。研究也表明随着加工距离的增大，等离子体边缘逐渐偏离局部热力学平衡状态，玻尔兹曼图谱法计算电子温度的适用性降低，导致等离子体边缘的温度拟合优度值逐渐降低。进一步对通入反应气体CF₄后的等离子体光谱进行了研究，通入反应气体后的等离子体呈现鲜亮的蓝绿色，是由于激发反应气体后产生的位于400~650 nm范围的带状光谱所致，分析表明谱图中的带状光谱为双原子分子C₂谱带Swan Bands，而该双原子分子是感耦氩等离子体对碳源CF₄的充分激发产生。

Research on the Electron Temperature and Emission Spectroscopy of the Atmospheric Inductively Coupled with Plasma Processing

As a novel technology in ultra‐smooth surface machining ,atmospheric pressure inductively coupled with plasma jet processing can produce plasma with high density and energy .This capability makes it a perfect medium in fully exciting the reac‐tive gases to improve the material removal rate .This paper is directed towards using the emission spectrometer to monitor and measure the spectra of the plasma jet from 400 ~ 1 000 nm .Spectral lines with obvious peaks and large energy differences are se‐lected from the measurement results to calculate the electron temperatures .The measured spectral data are the integrals of emis‐sion coefficients along the optical path ,and the plasma has a circularly symmetry with respect to the torch axis .Abel inversion transform is employed to compute the emission coefficients of the measured spectrum .These coefficients are then applied to ob‐tain the electron temperatures with Boltzmann plot method .The calculation results denote that the temperature profiles appear to be typically double‐peak profiles as a result of the skin effect and swirling inlet flow .With the increasing of off distance ,the double‐peak effect decreases and the profiles become smooth .The results also indicate that the plasma fringe is somewhat deviate from the local thermodynamic equilibrium ,and the applicability of Boltzmann plot method is reduced .Consequently the good‐ness‐of‐fit factors ,R‐Squared values ,on the plasma fringe are reduced .The spectra and characteristics of the argon plasma with reactive gas CF4 are also analyzed .This mixed plasma shows bright blue‐green color .The reason for the color is that some band spectra emerge between the range of 400 ~ 650 nm .These band spectra are the swan bands of diatomic C 2 which is formed by the fully excitation of carbon source CF 4 .