Investigation of non-equilibrium plasma processes in combined glow discharge

Abstract

Summary form only given. The combined glow discharge consists of a glow discharge and a capillary one. The present type of discharge was created to carry out the direct reduction of metals from oxides in non-equilibrium hydrogen plasma. A reducible oxide of metal in the form of a cylindrical tablet with the hole on the axis is set up in the positive column area of a glow discharge, which is burning in the tube with the diameter about 1 cm. The plasma-forming gas flows from anode to cathode. As a result, in the inner cavity of the tablet (diameter-few mm) a discharge with current density exceeding that in the glow discharge is obtained. Gas temperature in capillary area could come up to few thousand degrees, which results in evaporation and atomization of tablet material, in plasma-chemical reactions, which occur in plasma, on the surface of tablet and within it. Metal reduction process goes quickly at relatively low power supply. Different metal transfer methods are observed, the ion-plasma spraying method among them. The oxides of silicon and aluminum were used for investigation. There are very interesting possibilities for spectral analysis of powder materials. The heating up of a tablet of the substance under investigation is carried out from within. It provides the substance diffusion on the tablet axis, so the substance introduction into plasma method is realized. The substance fractional evaporation effect gives the opportunity to carry out not only elemental, but also phase analysis by temperature and discharge current gradually increase. The rotational, entering, electron plasma temperature and electron concentration have been measured. The main regularities of physico-chemical processes in CGD have been established.