In this paper, a model of an arc discharge in argon is formulated in a two-dimensional axisymmetric formulation. The results of numerical calculations for studying the parameters of the arc discharge plasma during the synthesis of silicon nanostructures are presented.

Plasma spraying coatings onto ceramic materials is used to solve a variety of technical problems. The plasma arc method allows for the production of thermal barrier and wear-resistant coatings made of oxides and carbides with thicknesses ranging from 100 to 300 microns, on surfaces with complex reliefs. The operational characteristics of the resulting products depend on the physico-chemical processes in the “ceramic substrate-coating” pair that occur during plasma spraying. In this study, plasma arc sprayed coatings of Al2O3 onto ceramic materials with high Si content ( 39 wt

Studies have been conducted on obtaining a powerful plasma flow using an electrolyte-cathode discharge. A distinctive feature is that the discharge burns horizontally. A cathode unit has been developed that changes the spatial orientation of the discharge. The process of transferring dissolved substances from liquid electrolyte to plasma and their entrainment by the plasma flow has been investigated.

In this paper, the synthesis of semiconductor spherical nanostructures is carried out by the plasma-chemical method. The sizes of the obtained nanospheres range from 100 nm to 1 mm. These structures are open on one side, have thin walls with a thickness of several nanometers, which end with “tentacles” with a diameter of several nanometers. Since the synthesis involved three elements of the fourth group of the periodic table (germanium, silicon, carbon), it has not yet been possible to determine the crystal structure of the obtained samples. All three elements are present on the surface of the sample in atomic percentages Ge-2.5%, Si-8%, C-55%. In addition to these elements, oxygen is also present in the spectrum.

This paper presents results on the synthesis of germanium nanocrystals in electric arc discharge. During the synthesis, the surface of a germanium anode was heated to the state of surface boiling. Atoms of vaporized germanium were deposited on the surface of a copper substrate. The resulting sample was examined with an electron microscope. The deposited material was shaped as crystalline nanospheres (nanocrystals) with a size ranging from 20 to 200 nm.

This paper presents the results of plasma synthesis of silicon nanostructures in an air-argon medium. The synthesis of silicon nanostructures was carried out in a vacuum chamber at a gas mixture pressure of 500 Torr, with partial pressures of argon and air in the ratio of 4:1. Molybdenum and silicon embedded in a copper tube were used as electrodes. Current and voltage were maintained in the range of 8-25 A and 30-50 V, corresponding. As a result of experiments, silicon nanostructures were deposited on the surface of the electrodes. Nanostructures were studied by optical and electron microscopes. Forms of silicon nanostructures were mainly in the form of nanotubes. Their diameters range from 200 nm to 500 nm, and their length reaches 1 mm. On the surface of these nanotubes, nanovilli with a diameter of about 5 nm and a length of 100 nm are observed.

Silicon coatings consisting of micro and nanopores were obtained by plasma-arc method. An experimental setup was assembled for the synthesis of nanostructures. A number of experiments on the synthesis of silicon nanostructures with changes in parameters such as current, voltage, and pressure in a vacuum chamber were carried out. In the experiments, a molybdenum cathode was used as a substrate for the deposition of silicon nanostructures. Atomic silicon evaporated from the anode. The experiments were carried out in an argon medium at a pressure of about 500 Torus. The current in the experiments is about 8 A, and the voltage is within 80 V. The resulting coatings with silicon nanostructures will increase the active surface area by several tens of times.

An original technique for the synthesis of germanium nanostructures in an electric arc argon plasma is described. The plasma–chemical synthesis of germanium nanotubes up to 100 μm long and up to 1 μm in diameter is performed by selecting the strength of the electric current, the pressure of the buffer gas, and the interelectrode distance. Individual nanotubes reach lengths of several mm. Unlike germanium nanotubes grown via CVD, the germanium nanotubes synthesized in this work have distinct shapes and sizes. They are separated from each other and can be easily manipulated. It is shown that this technique allows both germanium nanotubes and germanene to be grown.

A new method of synthesis of multilayer carbon nanotubes from liquid hydrocarbons is proposed. The interaction of an electric arc, fi ring between an anode and a cathode submerged in a thick layer of a heavy-hydrocarbon liquid, with hydrocarbon molecules was investigated for the purpose of obtaining new light fractions of oil and an atomic carbon. The carbonaceous substance deposited on the cathode was analyzed on an electron microscope. Chromatographic investigations of the products of the plasmachemical decomposition of heavy hydrocarbons have been performed. It was established that carbon nanotubes are present in a large amount in the deposit on the cathode and that the volatile oil fractions include gasoline fractions, acetylene, methane, ethane, and other substances.

A method for the synthesis of microdiamonds from graphite in an argon arc using germanium as a catalyst is presented. Simple microdiamonds and diamonds of complex configuration are obtained. It has been revealed that forms of synthesized nanomaterials are significantly affected by the buffer gas, the electrical and thermal parameters of the arc discharge, and the presence of germanium at the nucleation stage. Microdiamonds are formed within a few tens of seconds, which is much different from time required for their traditional production.