Diagnosis of Electron,Vibrational and Rotational Temperatures in an Ar/N2 Shock Plasma Jet Produced by a Low Pressure DC Cascade Arc Discharge

In this paper, a low pressure Ar/N2 shock plasma jet with clearly multicycle al- ternating zones produced by a DC cascade arc discharge has been investigated by an emission spectral method combined with Abel inversion analysis. Plasma emission intensity, electron, vi- brational and rotational temperatures of the shock plasma have been measured in the expansion and compression zones. The results indicate that the ranges of the measured electron temperature, vibrational temperature and rotational temperature are 1.1 eV to 1.6 eV, 0.2 eV to 0.7 eV and 0.19 eV to 0.22 eV, respectively, and it is found for the first time that the vibrational and rota- tional temperatures increase while the electron temperature decreases in the compression zones. The electron temperature departs from the vibrational and the rotational temperatures due to non-equilibrium plasma effects. Electrons and heavy particles could not completely exchange energy via collisions in the shock plasma jet under the low pressure of 620 Pa or so.

直流电弧喷射等离子体炬阳极喷嘴积碳现象的研究

采用高功率直流电弧等离子体喷射化学气相沉积工艺,制备了不同厚度的自支称金刚石厚膜。实验发现,等离子体炬阳极喷嘴积碳是沉积过程中最突出的问题之一。从理论和实验两个方面研究了阳极积碳产生的原因,并通过激光拉曼光谱分析了碳球的结构和成分。结果表明,碳球由金刚石层、混合层和最外面的石墨层构成。详细分析了甲烷浓度、冷却水温度、放电电弧的局部高温、阳极喷嘴的表面质量对积碳形成的影响,并提出了改进措施。