scholarly journals The mechanism of forming carbon nanostructures by electric arc-method

Surface ◽  
2020 ◽  
Vol 12(27) ◽  
pp. 263-288
Author(s):  
O. D. Zolotarenko ◽  
◽  
O. P. Rudakova ◽  
M. T. Kartel ◽  
H. O. Kaleniuk ◽  
...  
Keyword(s):  
Gas Phase ◽  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Research Work ◽  
Extreme Temperature ◽  
Electric Arc ◽  
Mechanisms Of Formation ◽  
Carbon Molecules ◽  
Reactor Space ◽  
Particles In Electromagnetic Fields

The regularities of the formation of nanostructures during the evaporation of graphite by the electric ARC – method are studied. Described physicochemical processes in the synthesis reactor . At plasma temperatures taking into account the behavior of particles in electromagnetic fields with extreme temperature and pressure grants. A sequence of organization of matter in the process of forming a structure according to nano-dimensional characteristics is proposed. The self-organization of systems during electric arc evaporation of graphite or graphite-containing electrodes has been studied. The mechanisms of formation of soluble (fullerenes and fullerene-like structures) and insoluble (nanocomposites, CNTs, graphenes) carbon nanostructures are considered. The processes occurring in the electric arc synthesis reactor are analyzed: the process of distribution of charged particles in an electric arc at different times; processes taking place at the anode; the mechanism of carbon vapor formation during graphite evaporation; processes in the gas phase and on the walls of the reactor under the conditions of an electric arc discharge; model of the reactor space zones; formation of carbon nanostructures in the gas phase and on the inner surface of the reactor. use of doped electrodes and metal inserts (sleeves) as catalysts for the synthesis of carbon nanostructures. The sequence of processes in the formation of spherical carbon molecules is studied, and the processes and structural transformations are considered. In the research work, the products (fullerenes and fullerene-like structures, nanocomposites, VNT, graphenes) of electric arc synthesis are presented, and modern methods of analysis are used for their fixation and identification.

scholarly journals Carbon Nanofoam by Pulsed Electric Arc Discharges

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
David Saucedo-Jimenez ◽  
Isaac Medina-Sanchez ◽  
Carlos Couder Castañeda
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Low Cost ◽  
Molar Fraction ◽  
Electric Arc ◽  
Graphite Electrodes ◽  
Electric Arc Discharge ◽  
Pure Carbon ◽  
Arc Discharges ◽  
Dc Current

The aim of this article was to report the carbon nanofoam synthesis by a new method and a new catalytic mixture. Using the pulsed electric arc discharge method, carbon nanofoam was synthesized. The synthesis was carried out in a controlled atmosphere at 200 torr of hydrogen pressure. The pulsed electric arc discharge was established between two graphite electrodes with 22.8 kVA of power and 150 A DC current; the cathode was relatively motionless and was made of a pure carbon rod of 6 mm diameter, and the spinner anode was a pure carbon disc spinning at 600 rpm; over the disc was an annular cavity where the new catalytic mixture of 93.84/2.56/1.43/0.69/1.48 of C/Ni/Fe/Co/S molar fraction was deposited in a geometrically fixed way by 8 catalytic mixture blocks and 8 empty spaces, and the discharge frequency was 80 Hz. After the synthesis was made, the resulting products were deposited on the electrodes, proving that our method can synthesize different carbon nanostructures easily and at low cost.

scholarly journals Arc-Induced Long-Period Fiber Gratings at INESC TEC. Part I: Fabrication, Characterization and Mechanisms of Formation

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4914
Author(s):  
Gaspar Rego ◽  
Paulo Caldas ◽  
Oleg V. Ivanov
Keyword(s):  
Arc Discharge ◽  
Electric Arc ◽  
Transmission Spectra ◽  
Fiber Gratings ◽  
Long Period ◽  
Electric Arc Discharge ◽  
Mechanisms Of Formation ◽  
Long Period Fiber Gratings ◽  
Fabrication Parameters

In this work, we reviewed the most important achievements of INESC TEC related to the fabrication of long-period fiber gratings using the electric arc technique. We focused on the fabrication setup, the type of fiber used, and the effect of the fabrication parameters on the gratings’ transmission spectra. The theory was presented, as well as a discussion on the mechanisms responsible for the formation of the gratings, supported by the measurement of the temperature reached by the fiber during an electric arc discharge.

scholarly journals Dry Etching Performance and Gas-Phase Parameters of C6F12O + Ar Plasma in Comparison with CF4 + Ar

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1595
Author(s):  
Nomin Lim ◽  
Yeon Sik Choi ◽  
Alexander Efremov ◽  
Kwang-Ho Kwon
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Reactive Ion Etching ◽  
Research Work ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Ar Plasma ◽  
Ar Gas ◽  
Etching Selectivity

This research work deals with the comparative study of C6F12O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes in a low power regime. Despite uncertain applicability of C6F12O as the fluorine-containing etchant gas, it is interesting because of the liquid (at room temperature) nature and weaker environmental impact (lower global warming potential). The combination of several experimental techniques (double Langmuir probe, optical emission spectroscopy, X-ray photoelectron spectroscopy) allowed one (a) to compare performances of given gas systems in respect to the reactive-ion etching of Si and SiO2; and (b) to associate the features of corresponding etching kinetics with those for gas-phase plasma parameters. It was found that both gas systems exhibit (a) similar changes in ion energy flux and F atom flux with variations on input RF power and gas pressure; (b) quite close polymerization abilities; and (c) identical behaviors of Si and SiO2 etching rates, as determined by the neutral-flux-limited regime of ion-assisted chemical reaction. Principal features of C6F12O + Ar plasma are only lower absolute etching rates (mainly due to the lower density and flux of F atoms) as well as some limitations in SiO2/Si etching selectivity.

Microfabricated Fiber Probe by Combination of Electric Arc Discharge and Chemical Etching Techniques

2012 ◽  
Vol 462 ◽  
pp. 38-41 ◽  
Author(s):  
Wan Maisarah Mukhtar ◽  
P. Susthitha Menon ◽  
Sahbudin Shaari
Keyword(s):  
Optical Fibers ◽  
Chemical Etching ◽  
Arc Discharge ◽  
Etching Rate ◽  
Electric Arc ◽  
Buffer Solution ◽  
Fiber Probe ◽  
Optical Fiber Probes ◽  
Electric Arc Discharge ◽  
Fiber Probes

In this study, optical fiber probes were fabricated by combination of electric arc discharge and chemical etching techniques. Size of tips diameters fabricated using different etching solutions were observed. When the optical fibers were pulled and heated by the electric arc discharge using a fusion splicer, fiber tips with few microns in diameter were obtained. To minimize the tips diameter, the pulled fiber probes were etched vertically for 10 minutes using two different etching solutions namely 49% HF and HF buffer solution (49% HF and 40% NH4F) with ratio of 2:1. A thick overlayer was added on top of the HF solution to prevent dangerous vapors escape to the environment. When the tapered part of the pulled fiber (FP1) was dipped into 49% HF solution, the diameter of tip was slightly decreased from 4.41μm to 1.31μm with etching rate of 5.17x10-3 μms-1. When the pulled fiber (FP2) was etched into HF buffer solution, the etching rate was increased up to 52.35% with the etching rate of 10.85x10-3μms-1. The tip diameter was reduced from 7.01μm to 468.9 nm in diameter. Combination of “heat and pull” technique with chemical etching by using HF buffer solution produced fiber probe with small tip diameter.

A study of helium gas clean-up in an electric arc discharge

1952 ◽  
Vol 71 (2) ◽  
pp. 159-164 ◽  
Author(s):  
M. J. Reddan ◽  
G. F. Rouse
Keyword(s):  
Arc Discharge ◽  
Electric Arc ◽  
Helium Gas ◽  
Electric Arc Discharge

scholarly journals Experimental study on high-efficiency DC short electric arc milling of titanium alloy Ti6Al4V

2021 ◽  
Author(s):  
Zongjie Zhou ◽  
Kai Liu ◽  
Yan Xu ◽  
Jianping Zhou ◽  
Lizhong Wang
Keyword(s):  
Titanium Alloy ◽  
Electrode Material ◽  
Material Removal ◽  
Electrode Materials ◽  
Arc Discharge ◽  
Specific Energy Consumption ◽  
Base Material ◽  
Electric Arc ◽  
Tool Electrode ◽  
Q235 Steel

Abstract Short electric arc milling (SEAM) is an efficient electrical discharge machining method, especially for the efficient removal of difficult-to-machine conductive materials with high hardness, high toughness, and wear resistance. In this study, titanium alloy Ti–6Al–4V is used as the research object to conduct machining experiments. The material removal mechanism of SEAM technology is studied using a DC power supply and different tool electrode materials (copper, graphite, Q235 steel, and titanium). The energy distribution of the discharge gap is analyzed using a data acquisition system and a high-speed camera. The arc is found to move with the spindle rotation in the process of arc discharge, and multi-point discharge occurs in the process of single-arc discharge. The voltage and current waveforms and the radius of the etched particles during the experiment were counted, the material removal rate (MRR) and relative tool wear rate (RTWR) are calculated, and the surface and cross-section micromorphology and hardness are analyzed. The experimental results show that when the electrode material is graphite, the maximum feed rate is 650 mm/min, the MRR can reach 17268 mm3/min, the ideal maximum MRR is more than 65000 mm3/min, and the RTWR is only 1.27%. When the electrode material is Q235 steel, the minimum surface roughness is 35.04 µm, and this material has good stability under different input voltages. When the electrode material is copper, the hardness of the resolidified layer is close to that of the base material, which is beneficial for further processing. The lowest specific energy consumption is 18.26 kJ/cm3 when titanium is used as the electrode material.

scholarly journals SPECTROSCOPY PECULIARITIES OF ELECTRIC ARC DISCHARGE PLASMA WITH IRON VAPOURS

2021 ◽  
pp. 171-175
Author(s):  
A. Murmantsev ◽  
A. Veklich ◽  
V. Boretskij
Keyword(s):  
Discharge Plasma ◽  
Arc Discharge ◽  
Line Emission ◽  
Plasma Temperature ◽  
Optical Emission ◽  
Plasma Source ◽  
Electric Arc ◽  
Spectral Lines ◽  
Electric Arc Discharge

This work is devoted to spectroscopy peculiarities of electric arc discharge plasma with iron vapours. The solution of the main issue of optical emission spectroscopy, namely, selection of iron spectral lines, to study the parameters of non-uniform and non-steady-state plasma source, was considered within this paper. Specifically, the Boltzmann plots technique was used for detailed analysing of application possibility of Fe I spectral lines as well as for determination of plasma temperature. The spatial profiles of selected spectral line emission intensities were used to measure the radial distributions of plasma temperature of free-burning arc discharge between consumable electrodes at 3.5 A.

scholarly journals Modeling of formation of carbon cluster groups in electric arc discharge plasma

2018 ◽  
Vol 80 (2) ◽  
pp. 108-113 ◽  
Author(s):  
A. N. Gavrilov
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Experimental Studies ◽  
Particle Method ◽  
Cost Effective ◽  
Carbon Cluster ◽  
Collision Integral ◽  
Numerical Calculations ◽  
Plasma Synthesis ◽  
Interelectrode Space

The problem of modeling complex resource-intensive processes of plasma synthesis of carbon nanostructures (CNS) on the basis of mathematical and numerical methods of solution, focused on the use of parallel and distributed computing for processing large amounts of data, allowing to investigate the relationship and characteristics of processes to obtain an effective, cost-effective method of synthesis of CNS (fullerenes, nanotubes), is an actual theoretical and practical problem. This article deals with the problem of mathematical modeling of motion and interaction of charged particles in a multicomponent plasma based on the Boltzmann equation for the synthesis of ONS by thermal sublimation of graphite. The derivation of the collision integral is presented allowing to perform a numerical solution of the Boltzmann - Maxwell equations system with respect to the arc synthesis of CNS. The high order of particles and the number of their interactions involved simultaneously in the process of synthesis of CNS requires significant costs of machine resources and time to perform numerical calculations on the constructed model. Application of the large particle method makes it possible to reduce the amount of computing and hardware requirements without affecting the accuracy of numerical calculations. The use of parallel computing technology on the CPU and GPU with the use of Nvidia CUDA technology allows you to organize all the General-purpose calculations for the developed model based on the graphics processor of the personal computer graphics card, without the use of supercomputers or computing clusters. The results of experimental studies and numerical calculations confirming the adequacy of the developed model are presented. Obtained quantitative characteristics of the total pairwise interactions between the carbon particles and interactions with the formation of clusters of carbon with various types of ties in the plasma of the interelectrode space which are the basis of the synthesized nanostructures. The formation of carbon clusters occurs in the entire interelectrode space of the plasma with different intensity and depends on the process parameters.

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