Generation of gas plasma by the hollow cathode arc discharge

This paper presents the design and principal characteristics of a generator of bulk low-temperature gas-discharge plasma, depending for its operation on a low-pressure arc discharge with a cold hollow cathode immersed in the axial magnetic field. The discharge of this type exists in the pressure range 4 x 10-2-1 Pa. The plasma generator makes it possible to produce homogeneous gas plasma of density ne=1010-1011 cm-3 and temperature Te=3 eV with the density distribution uniform within 15% in a vacuum volume of ∼0.25 m3 at discharge current of 60 A and magnetic field 2.0 x 10-2 T with a flow rate of 30-100 mPa·m3 s-1. Used for the plasma-generating gas were oxygen, methane, acetylene, nitrogen, and their mixtures with argon. After 70 h of operation in the chemically active gases, the parameters of the plasma generator changed insignificantly. The erosion rate of the hollow cathode surface was not over 10-6 g/C. The developed plasma generator can be used in technological processes of nitriding, cementation, and oxide coating as well as in the plasma-assisted gas-phase synthesis of diamond like coatings