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

以9kw的电能可稳定产生弱电离高温氮等离子体流。对设置钝圆柱体的流场进行光学诊断，测量氮气的振动温度和旋转温度，T_<vib>和T_<rot>。在马赫数为5和6的情况下，T_< t>分别为3000±500 K和2500±500 K。另一方面，在两种情况下，T_<vib>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造成这种现象的主要因素。暴露在等离子体流中的圆盘状黄铜的铜和锌组分在空间上发生了剧烈的变化。此外，发现这种弱电离氮等离子体流具有通过气体氮化使钢变硬的能力。维氏硬度为230的钢在维氏硬度为630时变得更硬，并且钢的硬度也发生了空间变化。这也表明，可以利用电离氮流来生产功能梯度材料。用电弧等离子体流装置电离了氮氧混合物，用玻尔兹曼图方法研究了中性O I和N I原子的光学性质。激发的O I和N I温度分别为18,500 K和17,500K。因此，自由电子的温度应为18000±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.