V. D. Shimanovich

An ARC Facility for Studying Carbon Plasma and Obtaining Low‐Dimensional Carbon Structures

An experimental DUF‐2000 facility for spectroscopic investigations of a reduced‐pressure carbon arc and also for production of low‐dimensional carbon structures (fullerenes, nanotubes, etc.) is described.

Features of radio-frequency alpha-discharges in Co 2 +N 2 +He gas mixtures for slab CO 2 lasers

The outcomes of spectroscopical investigations of RF-discharge plasma parameters are represented for the CO2 laser mixtures. The main emphasis is made on the exploration of spatial instabilities of luminescence intensity and gas temperature distribution in such discharge. Unlike the theoretical prediction it is shown that sizes of the sheath in a RF discharge weakly depend on excitation frequency and gas pressure.

Study of plasma formation in CW CO2 laser beam-metal surface interaction

An interaction of the cw CO2 laser beam and a moving metal surface has been studied. The pulsed and thermodynamical parameters of the surface plasma were investigated by optical and spectroscopical methods. The subsonic radiation wave propagation in the erosion plasma torch has been studied.

Thermal action of an electric arc on the wall of a planar gap

The distribution of thermal flux from a. dc arc with i=200–400 A located in a moving planar gap is studied experimentally. A model is proposed for the interaction of the moving heated gas flow, the dielectric wall, and the calorimeter.

PRODUCTION OF COATINGS FROM POWDER MATERIALS WITH THE USE OF A SHORT ARGON ARC. 2. HEAT FLUX FROM THE PLASMA TO A MACROPARTICLE

The heat flux to a metal particle in the plasma of a short argon arc of atmospheric pressure in depositing metallurgical coatings has been calculated. The limiting approximations of a continuum and free‐molecular flow yield comparable results (about 6·108 W/m2). The radiant‐flux density has been evaluated. It has been shown that the heating of macroparticles is determined mainly by the conductive mechanism of energy transfer.

Jet Formation in Plasma Sprayers

Optospectroscopic studies of plasma jets in powder sprayers have been made. It has been shown that the jet of the “Plasma‐Technik AG” sprayer is a periodically pulsating formation similar to that generated by the two‐jet plasma torch. A scheme of a plasmasonic reactor for treatment and synthesis of gaseous and condensed materials is proposed.

PRODUCTION OF COATINGS FROM POWDER MATERIALS WITH THE USE OF A SHORT ARGON ARC. 1. EXPERIMENTAL STUDY OF PLASMA HEATING OF MACROPARTICLES

Consideration is given to the processes of acceleration and heating of metallic particles in the device proposed by the authors for deposition of metallurgical coatings with the use of a short argon arc. The coatings produced are compared to those deposited by the traditional method of plasma spraying. Results of spectroscopic determinations of the temperature fields of the arc are given. The heat-flux density and the temperature of macroparticles are evaluated by the parameters of their destruction in the plasma found experimentally. The high efficiency of the technology proposed for heating of metallic powders, including high-melting ones, is shown.

Macroparticle acceleration in a carbon arc

Consideration is given to the mechanisms of acceleration of carbon macroparticles forming a cathode coating in a carbon arc under the conditions of fullerene formation. Based on experimental data and theoretical estimates, the macroparticle velocity is determined. It is shown that on collision of particles with the cathode surface the conditions are realized in the zone of contact where graphite fusion can occur.

Parameters of the Plasma of the Argon Arc Used to Deposit Coatings

We consider an argon d.c. arc in the device devised by us for depositing metallurgical coatings. The temperature and concentration fields of electrons needed to construct the quantitative model of heating of particles in a plasma stream are determined by spectroscopic methods.

Light-Induced Cooling of the Active Medium of a Fast-Circulation CO2 Laser in the Field of Generated Radiation

Using the methods of emission spectroscopy, we studied the influence of generated radiation on heating the active medium of a fast-flow electric-discharge CO2 laser.