Investigation of the Condition of the Gold Electrodes Surface in a Plasma Reactor

During the long-term operation of a plasma reactor, decreases in plasma concentration were noticed despite the constant maintenance of all parameters. One of the factors was the decrease in the nitrogen content on the electrode surface; in order to eliminate it, the supply voltage was increased up to 11 kV. Another decisive factor in the plasma concentration decrease was the oxidation of the electrode surface. These effects were studied using two electrodes: a gold one and a copper one coated with a 10 μm thick layer of galvanized gold. In the experiment with the gold coated electrode, a large decrease in plasma concentration was observed. High-energy electrons knocked out the gold atoms from the electrode; as a result, the gold atoms evaporated and the raids layers formed. After the electrodes had been in operation for a month, metallographic analyzes were carried out, the results of which are described in this paper.