Reduction of the metal impurity flux to the Uragan-3 torsatron plasma by the use of RF TiN-coated antennas

Abstract Results obtained in the study of some properties of vacuum plasma deposited coatings are reported. Hydrogen permeability, sputtering yields of coatings bombarded with He + and Ar + ions, blister formation under irradiation with 80 keV He + ions, and arcing under the plasma action have been measured. As a result, the TiN coating has been found to be essentially more resistant (as compared with stainless steel) to erosion caused by plasma action. Results obtained from experiments in the Uragan-3 torsatron using stainless steel antennas with and without a TiN coating are compared. The employment of TiN-coated antennas ensured an essential reduction (more than by an order of magnitude) of the flux of metal atoms arriving to the plasma during an RF pulse.