Denis Ponomarev

Pulse Plasma-Chemical Synthesis of Ultradispersed Powders of Titanium and Silicon Oxide

This paper is devoted to studying the plasma-chemical synthesis of nanosized SiO2 and TiO2 powders and to the analysis of their major characteristics. The nanosized powder was synthesized in the plasma-chemical reactor using a pulse electron beam to generate low-temperature plasma. The synthesized powders were studied by the transmission electron microscopy to determine the morphology and the size of the nanosized powder with respect to by-products of the reaction. The elemental composition was studied using the Oxford ED2000 X-ray fluorescent spectrometer. To determine the crystal structure of the nanosized powder, we used the standard technology of X-ray phase analysis. The reaction products were processed using Shimadzu XRD-6000/7000. The substances included in the composition of the nanosized powder were identified using Nicolet 5700 Fourier transform infrared spectrometer.

Pulsed plasma chemical synthesis of SixCyOz composite nanopowder

SixCyOz composite nanopowder with an average size of particles about 10-50 nm was produced using the pulsed plasma chemical method. The experiments on the synthesis of nanosized composite were carried out using a TEA-500 pulsed electron accelerator. To produce a composite, SiCl4, O2, and CH4 were used. The major part of experiments was conducted using a plasma chemical reactor (quartz, 140 mm diameter, 6 l volume). The initial reagents were injected into the reactor, then a pulsed electron beam was injected which initiated the chemical reactions whose products were the SixCyOz composite nanopowder. To define the morphology of the particles, the JEOL-II-100 transmission electron microscope (TEM) with an accelerating voltage of 100 kV was used. The substances in the composition of the composite nanopowder were identified using the infrared absorption optical spectrum. To conduct this analysis, the Nicolet 5700 FT-IR spectrometer was used.

Pulsed plasma chemical synthesis of carbon-containing titanium oxide-based composite

ABSTRACT The carbon-containing titanium oxide-based composite was first obtained using a pulsed plasma chemical method. The composite was obtained from the following reagents: TiCl4, CH4, and O2. The physical and chemical properties of the TixCyOz composite powders were studied (morphology, chemical, elemental and phase composition). The presence of spherical particles and the cubic and prismatic particles were typical for the synthesised carbon-containing titanium oxide-based composites. The large particles are observed (the average size exceeds 150 nm) and smaller particles (the average size is 15–30 nm). The presence of the dense layer of amorphous carbon (10–15 nm thick) around particles is typical for the composites. The peak with a maximum of 1080 cm−1 is registered in IR absorption spectrum of the TixCyOz synthesised composite. The presence of IR radiation in this region of the spectrum is typical for the deformation of atomic oscillations in the Ti-O-C bond, which indicates that carbon and titanium in the composite are bound through oxygen. The content of the defined amount of titanium carbide has not been detected.

Pulsed electron beam propagation in argon and nitrogen gas mixture

The paper presents the results of current measurements for the electron beam, propagating inside a drift tube filled in with a gas mixture (Ar and N2). The experiments were performed using the TEA-500 pulsed electron accelerator. The main characteristics of electron beam were as follows: 60 ns pulse duration, up to 200 J energy, and 5 cm diameter. The electron beam propagated inside the drift tube assembled of three sections. Gas pressures inside the drift tube were 760 ± 3, 300 ± 3, and 50 ± 1 Torr. The studies were performed in argon, nitrogen, and their mixtures of 33%, 50%, and 66% volume concentrations, respectively.

Influence of current – conducting inserts in a drift tube on transportation of a pulsed electron beam at gigawatt power

This paper describes the results of experimental research on the influence of the current-conducting inserts in a drift tube on transportation of a pulsed electron beam at gigawatt power and nanosecond duration. The experimental investigation was conducted using a TEU–500 laboratory-pulsed electron accelerator (parameters of the accelerator: Up to 550 keV; output electron current: 11.5 kA; pulse duration (at half-height): 60 ns; pulse frequency: 5 pulses/s; pulse energy: Up to 280 J). Air was chosen as the propagation medium. The pressure in the drift tube is 50 Torr. It is revealed that the pulsed electron beam transport depends on the geometry of the current-conducting inserts in a drift tube. The direction of the pulsed electron beam propagation can be regulated by changing the geometry of the current-conducting insert. The experimental research was verified by theoretical calculations.

Propagation of the pulsed electron beam of nanosecond duration in gas composition of high pressure

This paper presents the results of the investigation of the propagation of an electron beam in the high-pressure gas compositions (50, 300, and 760 Torr): sulfur hexafluoride and hydrogen, sulfur hexafluoride and nitrogen, sulfur hexafluoride and argon. The experiments have been performed using the TEA-500 laboratory accelerator. The main parameters of the accelerator are as follows: an accelerating voltage of 500 kV; an electron beam current of 10 kA; a pulse width at half maximum of 60 ns; a pulse energy of 200 J; a pulse repetition rate of up to 5 pulses per second, a beam diameter of 5 cm. The pulsed electron beam was injected into a 55 cm metal drift tube. The drift tube is equipped with three reverse-current shunts with simultaneous detecting of signals. The obtained results of the investigation make it possible to conclude that the picture of the processes occurring in the interaction of an electron beam in the high-pressure gas compositions is different from that observed in the propagation of the electron beam in the low-pressure gas compositions (1 Torr).

Investigation of the propagation of a gigawatt pulsed electron beam in compositions of high-pressure gas

The paper presents the results of the experimental investigation of pulsed electron beam propagation with a varying current density (electron energy Ee = 350–400 keV; total current of a diode Ie up to 11 kA; (half-amplitude) pulse duration t = 60 ns, pulse energy We up to 120 J) in two- and three-component gas compositions used in the pulsed plasma chemical synthesis of nanosized oxides. The mean value of the specific absorbed energy within the zone of pulsed electron beam propagation with a current density of 0.05–0.06 kA/cm2 in gas compositions has been determined.

Features of pulsed electron beam propagation with nanosecond duration in the air under the low (reduced) pressure

This paper presents the research of pulsed electron beam propagation with nanosecond duration in the air under the low pressure (3-8 Torr) with the help of a calorimeter with a vacuum cutoff and a Faraday cup. Investigations have been conducted with the laboratory setup, including the TEU-500 electron accelerator and a drift tube. The major parameters of the accelerator are as follows: 450-500 keV electron energy; 9-12 KA ejected electron current; 60 ns half-amplitude pulse duration; 5 pps pulse repetition rate; and 250 J pulse energy.

Study on nanosecond pulsed electron beam generation

The paper presents the findings of an investigation on volt-ampere characteristics of the diode with explosive emission cathodes of different constructions (blade metal-dielectric (MD-cathode) and solid graphite cathodes) under the change of the anode-cathode gap in wide ranges. The investigations were carried out using the TEA-500 pulsed electron accelerator. The total current of the electron beam was measured using the Faraday cup (FC). A 0.5-mm foiled glass fiber laminate was used as an emitting edge of the cathode in the experimental study with the explosive emission blade MD-cathode. Based on the obtained results, the conclusion was made that the graphite cathode has the most effective efficiency factor.

Optical properties of carbon-containing titanium oxide nanocomposites obtained by the pulsed plasma chemical method

ABSTRACT This paper presents the results of an experimental investigation on the optical properties of the TiO2 and TixCyOz nanopowders, produced by the pulsed plasma chemical method. Pulsed plasma chemical synthesis is realized on the laboratory stand, including a plasma chemical reactor (6 l) and TEA-500 electron accelerator. The parameters of the electron beam are as follows: 400–450 keV electron energy, 60 ns half-amplitude pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. In TiO2 sample, obtained using the pulsed plasma chemical method, the particles can be divided into two groups: 100–500 nm large spherical particles and tiny complex particles (sized less than 100 nm). For TixCyOz sample, the morphology of the particles is mainly presented with irregular fragment shape. The average size of the particles is ranged from 200 to 300 nm. The band gap for all synthesized samples is within 2.94–3.35 eV.