Development of a plasma system based on gridless ion acceleration for deposition of aluminum oxide coatings

Abstract

An electrode scheme containing two low-temperature plasma-physical devices was developed and implemented. The gas and a metal-containing plasma generating in this system are divided. The low-temperature plasma generation in the discharge with the external electrons injection through a double electrostatic layer, without overlapping of the output emission window with a plasma-limiting grid is producing in the system. It was shown that a change in the arc current with the cathode spot does not cause significant changes in the thermionic cathode discharge operation, while the thermionic cathode discharge operation conditions and the accelerating voltage significantly affect the main characteristics of the system operation. The measured concentration of gas-metal discharge plasma with the external electrons injection may exceed 3 × 10¹⁸ m⁻³ in the volume of ∼ 1 × 10⁻³ m³. The energy and current density of ions accelerated in the developed plasma system were studied, the possibility of ion flux forming with particle energy of tens of eV and current density of up to 100 A/m² without overlapping the emission window with a plasma-limiting grid was shown. The possibility of α-alumina containing coatings forming was demonstrated in test deposition experiments.