Low-pressure discharges with hollow cathode and hollow anode and their applications

Abstract

The review relates to low-pressure discharges with a hollow cathode and a hollow anode. The term ‘low pressure’ implies that a neutral particle density is extremely small and the electron free path for ionization is in excess of the characteristic size for the discharge gap. On the other hand, the neutral particles still play an essential role in forming the gas-discharge plasma. Thus, the discharge regimes keep an intermediate position between the classical low-pressure discharge with avalanche ionization and pure vacuum discharge that burns in the cathode metal vapor. New approaches to the interpretation of the discharge formation mechanism at the stage of delay time to breakdown, and for the discharge sustaining features at the later temporal stages, are discussed. The developed approaches offer the possibility of interpreting the discharge behavior in the systems to obtain a uniform plasma in a large volume of the cathode or anode cavity, in the sources of electron and ion beams based on the plasma cathode and in the high-current pseudospark switches.

Combined Processing of Micro Cutters Using a Beam of Fast Argon Atoms in Plasma

“…Due to the etching, the cutting edge radius diminishes to ≈3−4 µm from the minimum value of ≈10−11 µm available with the tool sharpening through grinding. The sharpening occurs due to a quite homogeneous sputtering of the tool surface near the edge at low gas pressure p < 1 Pa. Homogeneous plasma inside the chamber is generated by the glow discharge with a large hollow cathode [48], which is the vacuum chamber itself.…”

Disclosure of water roles in gliding arc plasma reforming of methanol for hydrogen production

“…Methanol steam reforming (R1), [2] CH OH + H O CO + 3H , also believed as the combination of methanol decomposition or pyrolysis (R2), [3] CH OH CO + 2H , offers higher hydrogen atom utilization [4] than its partial oxidation (R4), [5] CH OH + 0.5O CO + 2H , 3 2 2 2 → (R4) and, thus, is more suitable for hydrogen infrastructure. For distributed hydrogen production, the nonthermal plasma reforming technique [6][7][8][9][10][11][12][13][14][15][16] has greater advantages than conventional catalysis, due to its compact configuration and rapid response. Many studies on hydrogen production from methanol-reforming have been reported using nonthermal plasmas, such as microwave discharge, [17][18][19] gliding arc (GA) discharge, [20][21][22][23] dielectric barrier discharge (DBD), [24][25][26] and corona discharge, [27] including a few of mechanism research based upon density functional theory (DFT).…”

Surface Hardening of Machine Parts Using Nitriding and TiN Coating Deposition in Glow Discharge

“…They are used to etch the surface, as well as to accompany the deposition of coatings [14]. Glow discharge with a cold hollow cathode enables the filling of the chambers with homogeneous plasma and ion-plasma processing of products immersed therein [15,16]. The present research is aimed at a combined hardening of machine parts in this plasma, which determines their surface nitriding and the deposition of hard wear-resistant coatings.…”