Glow Discharge
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Jochen Busam ◽  
Gagan Paudel ◽  
Marisa Di Sabatino

We demonstrate and compare indium and silicon as secondary cathode material for the analysis of flat, solid alumina and sapphire matrices by direct-current glow discharge mass spectrometry (dc-GDMS). The mask...

Quan-fang Lu ◽  
Juan-long Li ◽  
Jie Yu ◽  
Li-juan Cui ◽  
Bo Wang ◽  

Abstract Tantalum pentoxide nanoparticles (Ta2O5 NPs) were fabricated by cathode glow discharge electrolysis (CGDE) generated between a needle-like platinum wire cathode and a tantalum foil anode in 6 g L−1 Na2SO4 electrolyte solution containing 5 mL hydrofluoric acid (HF) and 0.075 g cetyltrimethyl ammonium bromide (CTAB). The chemical structure, composition and morphology of the obtained powder were analyzed by using XRD, FT-IR, SEM/EDS, XPS and UV-vis DRS. The results found that Ta2O5 NPs with orthorhombic structure and wide band gap (3.6 eV) are successfully fabricated at 500 V discharge voltage in about 3 h. CTAB as a stabilizing agent can reduce the agglomeration due to forming CTA+ and attaching the surface of the synthetic products. A possible preparation mechanism of Ta2O5 NPs is proposed. Firstly, the tantalum foil anode is oxidized to form a compact Ta2O5 layer. Then, Ta2O5 surface is etched to form soluble [TaF7]2− complexes in the presence of HF. After that, soluble [TaF7]2− complexes can react with H2O to form Ta(OH)5. Finally, Ta(OH)5 is further converted to Ta2O5 from plasma-liquid interface into solution.

Jing Zhang ◽  
Shurong Ye ◽  
Tianxu Liu ◽  
Anbang Sun

Abstract The products of hydrogen sulfide decomposition by dielectric barrier discharge are hydrogen and sulfur. This process can successfully recover hydrogen from a hazardous by product of fossil fuel extraction, and it has thus been attracting increasing attention. In this study, we computationally examined the dynamics of dielectric barrier discharge in hydrogen sulfide. The simulations were performed with a 1d3v particle-in-cell/Monte Carlo collision model in which a parallel-plate electrode geometry with dielectrics was used. Particle recombination process is represented in the model. The discharge mode was found to be initially Townsend discharge developing from the cathode to the anode, and at the peak of the current, a more stable glow discharge develops from the anode to the cathode. A higher applied voltage results in sufficient secondary electrons to trigger a second current peak, and then the current amplitude increases. As the frequency is increased, it leads to the advance of the phase and an increase in the amplitude of the current peak. A higher dielectric permittivity also makes the discharge occur earlier and more violently in the gap.

Igor Melnyk ◽  
Sergey Tugay ◽  
Volodymyr Kyryk ◽  
Iryna Shved

The algorithm is considered for calculating the focal distance of a hollow conical electron beam generated by high-voltage glow discharge electron guns with magnetic focusing of the beam in the drift region, as well as a method for calculating the diameter of the focal ring and its thickness for such a beam. The proposed algorithm is based on the theory of electron drift in the field of a focusing magnetic lens and is designed using the methods of discrete mathematics and the minimax analysis. The obtained simulation results made it possible to establish the influence of the magnetic lens current on the focal diameter of a hollow conical electron beam and on its focal ring thickness. It is shown that the change in the focal parameters of a hollow conical electron beam can be effectively provided through the regulation of the magnetic lens current.

N. V. Landl ◽  
Y. D. Korolev ◽  
O. B. Frants ◽  
V. G. Geyman ◽  
G. A. Argunov ◽  

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2063
Stephan Renninger ◽  
Paul Rößner ◽  
Jan Stein ◽  
Maike Lambarth ◽  
Kai Peter Birke

Plasma technology reaches rapidly increasing efficiency in catalytic applications. One such application is the splitting reaction of CO2 to oxygen and carbon monoxide. This reaction could be a cornerstone of power-to-X processes that utilize electricity to produce value-added compounds such as chemicals and fuels. However, it poses problems in practice due to its highly endothermal nature and challenging selectivity. In this communication a glow discharge plasma reactor is presented that achieves high energy efficiency in the CO2 splitting reaction. To achieve this, a magnetic field is used to increase the discharge volume. Combined with laminar gas flow, this leads to even energy distribution in the working gas. Thus, the reactor achieves very high energy efficiency of up to 45% while also reaching high CO2 conversion efficiency. These results are briefly explained and then compared to other plasma technologies. Lastly, cutting edge energy efficiencies of competing technologies such as CO2 electrolysis are discussed in comparison.

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1818
Huirong Li ◽  
Yueying He ◽  
Haichao Zhang ◽  
Tao Ma ◽  
Yungang Li

The casting compounding process for copper-steel composite material has broad prospects of application, but due to the lack of supporting theories (especially the bonding mechanism of copper-steel at high temperatures), it is developing slowly. In this research, copper-steel composite materials for different casting temperatures have been prepared by the casting compound process. The results show that, for the casting compound process, the stable copper-steel transition layer can be formed in a short time, and the bonding of copper and low carbon steel is the result of both the diffusion of Cu in low carbon steel and the dissolution of Fe in molten copper. The diffusion coefficient of Cu in the low carbon steel is mainly concentrated in the range of 4.0 × 10−15–8.0 × 10−14 m2/s. However, for casting compound process of copper-steel, as the temperature rises the thickness of the copper-steel transition layer gradually decreases, while the Fe content in the copper layer gradually increases. At the same time, the analysis of the glow discharge results shows that, during the solid-liquid composite process of copper-steel, the element C in steel has a great influence. As the temperature rises, the segregation of C intensifies seriously; the peak of the C content moves toward the copper side and its value is gradually increases. The segregation of C would reduce the melting point of the steel and cause irregular fluctuations of the diffusion of Cu in low carbon steel. Therefore, a relatively lower molten copper temperature is more conducive to the preparation of copper-steel composite materials.

2021 ◽  
Vol 2064 (1) ◽  
pp. 012118
A S Klimov ◽  
I Y Bakeev ◽  
A A Zenin

Abstract The influence of the size of a cathode gap on the initiation of the effect of a hollow cathode in a glow discharge system with an extended hollow cathode in the forevacuum pressure range is shown. It was found that the threshold current for the transition of the discharge to the burning mode with a hollow cathode is determined by the ratio of the longitudinal and transverse dimensions of the cathode slit. With a decrease in the width of the slot, the threshold current increases disproportionately; at the same time, with an increase in the length of the slot, this current sharply decreases.

2021 ◽  
Vol 2064 (1) ◽  
pp. 012007
G A Argunov ◽  
N V Landl ◽  
Y D Korolev ◽  
O B Frants ◽  
V G Geyman ◽  

Abstract This paper describes a method of nanosecond triggering for the modified version of the commercially produced pseudospark switch TPI1-10k/50. The switch uses the trigger unit with the auxiliary glow discharge, and the proposed method is based on the principle of the current interception from the trigger unit to the grounded cathode cavity when the trigger pulse arrives. Different electric circuits for triggering have been investigated. In the circuit, where the so-called trigger resistor or the trigger inductance are available, in the whole range of hydrogen operating pressure, the range of the delay time of triggering corresponds to (80–100) ns with a jitter of (3–6) ns. In the electric circuit, where the trigger resistor is shortened, the delay time increases to about (110–140) ns. However, the jitter remains at approximately the same level.

A. Breus ◽  
S. Abashin ◽  
O. Serdiuk

Purpose: The application of a common magnetron discharge to the growth of carbon nanostructures is studied. The simplicity of the proposed technique can be beneficial for the development of new plasma reactors for large-scale production of carbon nanostructures. Design/methodology/approach: Graphite cathode was treated by carbon-containing powder accelerated by use of nozzle, and then aged in hydrogen. Superposition of glow and arc discharges was obtained, when putting the cathode under the negative biasing with respect to the walls of a vacuum chamber. The pulsed discharge was preserved through the whole time of treatment. This process was explained in terms of interaction of glow discharge plasma with a surface of the cathode made of non-melting material. Findings: The plasma treatment resulted in generation of the diverse nanostructures confirmed by SEM and TEM images. Spruce-like nanostructures and nanofibers are observed near the cathode edge where the plasma was less dense; a grass-like structure was grown in the area of “race-track”; net-like nanostructures are found among the nanofibers. These findings allow concluding about the possible implementation of the proposed method in industry. Research limitations/implications: The main limitation is conditioned by an explosive nature of nanostructure generation in arcs; thus, more elaborate design of the setup should be developed in order to collect the nanospecies in the following study. Practical implications: High-productivity plasma process of nanosynthesis was confirmed in this research. It can be used for possible manufacturing of field emitters, gas sensors, and supercapacitors. Originality/value: Synthesis of carbon nanostructures is conducted by use of a simple and well-known technique of magnetron sputtering deposition where a preliminary surface treatment is added to expand the production yield and diversity of the obtained nanostructures.

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