Application of a weak-ionized plasma high-temperature flow for material development and treatment of hazardous substance, and its flow diagnostics

当电能为9kW时，可以稳定地产生弱电离高温氮等离子体流。对设置钝化圆柱体的流场进行了光学诊断，以测量氮气、T_lt；VIB&GT；和T_&lt；Rot&Gt；的振动和旋转温度。马赫数为5和6的情况下，T&lt；rot&gt；分别为3,000±500 K和2,500±500 K。另一方面，在两种情况下，T&lt；VIB和GT；在整个流场中几乎是恒定的。认为氮分子与电子碰撞所需的时间和碰撞频率可能是主要原因。盘状黄铜在等离子体流中暴露后，铜和锌的成分在空间上发生了很大的变化。此外，还发现这种弱电离氮等离子体流具有通过气体渗氮使钢变硬的能力。维氏硬度为230的钢随着维克斯值为630而变得更硬，钢的硬度也在空间上发生了变化。利用电弧等离子体流动装置对氮氧混合物进行了电离，并用Boltzmann图方法对中性O原子和N I原子进行了光学研究。测得O_i和N_i的激发温度分别为18500K和17500K。因此，自由电子的温度应为18,000±500K。

Weak ionized high temperature nitrogen plasma flow could be generated stably with the electrical energy of 9 kW. Optical diagnostics for the flow field, where a blunt cylindrical body was set, was undertaken to measure vibrational and rotational temperatures of the nitrogen, T_<vib> and T_<rot>. T_<rot> was 3,000±500 K and 2,500±500 K for the case of Mach number 5 and 6, respectively. On the other hand, T_<vib> was almost constant in the whole flow field for the both cases. It is considered that the required time for a nitrogen molecule to collide with an electron and its collision frequency might be the major factors for the reason.Copper and zinc components of a disc-shaped brass, which was exposed in the plasma flow, was drastically changed spatially. Furthermore, this weak ionized nitrogen plasma flow was found to have the ability to make steel hard by the gas nitriding. The steel with the Vickers hardness of 230 changed to be harder with the Vickers value of 630, and hardness of the steel was also changed spatially. It also suggests that the ionized nitrogen flow can be utilized to product a functionally gradient material.Nitrogen and oxygen mixture was ionized by the arc-plasma flow facility and the neutral O I and N I atoms was investigated optically by the Boltzmann plots method. The excited O I and N I temperatures were delived to be 18,500 K and 17,500K, respectively. Therefore, the temperature of a free electron should be 18,000±500K.