Contents

Plasmochemical methods of production and treatment of materials

V.I. Kalita, A.A. Radyuk, D.I. Komlev, A.Yu. Ivannikov, Yu.V. Blagoveshchensky,

K.V. Grigorovich, T.V. Shibaeva

Plasma coatings of mechanically alloyed powders WC-Co-C....................................................................................................... 5

For production of plasma WC-Co coatings with controlled phase composition and carbon content, carbon

black in an amount of 30 and 40% of the stoichiometric carbon content was added to industrial WC-17% Co

powder before the powder mechanical alloying (ML). After ML, powders were pressed, sintered and crushed

to a particle size 25-71 mm required for spraying . Coatings were sprayed on the plasma unit with the free air

local protection. Phase composition, carbon content, and microhardness of the coatings have been controlled at

all stages of the coating production and treatment. The total loss of carbon during the coating deposition

process is found to be 31,9-43,6%.

Keywords: plasma coatings, local protection, tungsten carbide, cobalt, mechanical alloying, control of

carbon content, microhardness.

 

S.V. Anakhov, N.B. Pugacheva, Yu.A. Pykin, A.V. Matushkin, T.M. Bykova

Metallographic analysis of the structure of welded joints produced with the use of plasma cutting of blank parts..................... 16

By metallographic analysis, the structure of the welded joints produced with the use of plasma cutting of

structural low-alloyed steel has been investigated. It is shown that a quality of the joint welds of material

blanks after plasma cutting without removal of heat-affected zone is to be not worse than that after mechanical

cutting. Application of a new one-circuit plasmatron with the improved gas dynamic characteristics as well

as a narrow-jet plasmatron for metals cutting allows to obtain an advanced welded joints with a high efficiency

and low power expenses.

Keywords: plasmatron, welded joints, heat-affected zone, structure transformations, defects.

 

E.A. Bogoslov, M.P. Danilaev, Yu.E. Polsky, M.S. Pudovkin

Formation of polystyrene film in gas discharge plasma at atmospheric pressure...................................................................... 23

Conditions for by-product (carbon particles) free polystyrene film coatings formation in gas discharge plasma at

atmospheric pressure have been investigated. The presence of the carbon particles decreases the adhesion of

polymer film to a substrate. It is ascertained that by-products are not formed under barrier discharge power less

than 200 W and discharge current density lower than 25 mA/cm2.

Keywords: polystyrene films, barrier discharge plasma.

 

D.V. Sitanov, A.A. Anzhaurov

Plasma visualization of biologically active points on a human skin............................................................................................ 28

On the base of analysis of an experimental data on the patterns of air plasma emission in a surface barrier

discharge near the surface of a human skin, the method of plasma visualization of biological active points (BAT)

has been proposed. Physical effects responsible for BAT visualization on a human skin have been considered.

Apparatus for the practical realization of the method proposed are described.

Keywords: barrier discharge in the air, the point on the human skin, plasma visualization.

 

Functional coatings and surface treatment

N.V. Kobernik, R.S. Mikheev, I.E. Kalashnikov, L.I. Kobeleva, L.K. Bolotova

Tribological properties of the babbit alloy coatings modified with carbon nanotubes................................................................ 32

Tribological properties of the composite coatings produced by the plasma-powder surfacing on a steel substrate

have been investigated. The powder from babbit SnSb8Cu4 alloy and composite pellets on the base of babbit

alloy and carbon nanotubes (CNT) were used as adding materials. Carbon nanotubes were produced by the method

of catalytic pyrolysis of propane-butane mixture over a NiO/MgO catalyst and by synthesis of carbon nanostructures

on the surface of copper powder in the absence of catalyst particles. The comparison of friction coefficient and wear

rate values for the coatings modified and non-modified with with CNT was carried out.

Keywords: carbon nanotubes, babbit alloy, antifriction coatings, plasma-powder surfacing.

 

O.B. Perevalova, A.V. Panin, M.P. Kalashnikov, A.A. Akulinkin, I.A. Bozhko, V.P. Sergeev

Elastic stresses and microstructure of TiAlN coatings................................................................................................................ 40

By X-ray diffraction and TEM methods, the phase composition, macro- and microstresses and microstructure in

Ti1xAlxN coating and substrate have been investigated. The coating was deposited by magnetron sputtering of

Ti-Al target in Ar+N gaseous mixture on austenitic steel substrate preliminary bombarded with Ti ion beam.

It was found that the increase of duration of ion treatment leads to increasing the compression macrostresses and

refining of nanocrystalline columnar microstructure in Ti1xAlxN coating.

Keywords: coating, nanocrystalline columnar microstructure, phase composition, X-ray analysis, transmission

diffraction electron microscopy, macro- and microstresses.

 

S.A. Nikukin, V.M. Khatkevich, S.O. Rogachev, K.S. Denisenko, T.A. Nechaykina

Structure and mechanical properties of Fe-Cr-V alloy saturated with nitrogen from

the gaseous phase by high-temperature nitriding........................................................................................................................ 52

Microstructure, phase composition, and mechanical properties of corrosion resistant Fe-20% Cr-5% V alloy

doped with nitrogen by high-temperature gas-phase nitriding have been investigated. Nitriding of the Fe-20%

Cr-5% V alloy (T=950-1100C) and subsequent annealing (T=700C) leads to precipitation of a large

vanadium nitrides and disperse chromium nitrides particles in a ferrite matrix. This treatment increases the

strength of the Fe-20% Cr-5% V alloy at room temperature by 1.6 times while maintaining sufficient ductility

level.

Keywords: high-temperature nitriding, corrosion-resistant alloys, nitrides, microstructure, mechanical properties.

 

A.S. Khlebinskaya, L.P. Mileshko, A.I. Koroleva

Thermodynamic functions of the reaction of anode oxidation of valve metals in phosphate electrolytes..................................... 40

It is shown that reactivity of valve metals in relation to the phosphate anions of electrolytes decreases in a row

Hf→Zr→Y→Er→Ho→Gd→Al→Ta→Nb. It is established that as a result of anodic reactions taking place on

valve metals in phosphate electrolytes, together with metal oxides formed P2O5.

Keywords: anodization of metal oxide, anodic oxide film, phosphate anions, the thermodynamic analysis.

 

Composite materials

V.I. Kotlyarov, V.T. Beshkarev, V.E. Kartsev, V.V. Ivanov, A.A. Gasanov, E.A. Yuzhakova,

A.V. Samokhin, A.A. Fadeev, N.V. Alekseev, M.A. Sinaysky, E.V. Tretyakov

Production of spherical powders on the basis of group IV metals for additive manufacturing................................................... 63

The method of Group IV metals powders production for additive technologies is presented. Powders are

produced in the hydrogenation-dehydrogenation process followed by plasma spheroidization of prepared

polygonal powders. Dependence of hydrides composition on amount of the absorbed hydrogen is established

for group IV metals, it allows to optimizing technological parameters of processes for hydrogenation and

grinding. It is shown that spherical powders of titanium and vanadium and Zr-10% Ti alloys may be produced

in Ar+8 vol.% H2 plasma jet generated by DC plasma torch. Degree of spheroidization of the powders with

fraction of 40-70 μm and <40 μm reaches 96%, and an average roundness factor of it is 1.01 varying in the

range 1-1.4.

Keywords: metallic powders, additive manufacturing, hydrogenation, dehydrogenation, titanium,

plasma spheroidization.

A.G. Zholnin, I.V. Kovaleva, V.R. Rytenko, I.O. Pahilo-Daryal, I.S. Litvinova,

V.Yu. Goltsov, E.G. Grigoryev, E.A. Olevsky

Effect of the size of alumina powder particles on the results of spark-plasma sintering............................................................. 71

By The results of comparative investigations of the compacts produced by spark-plasma sintering of globular

particles of nano- and superdispersed (SD) alumina powder have been presented. It is shown the compacts from

SD powder have advantages compared to those from nanopowders owing to the higher density, microhardness,

and bend test strength values as well as more fine-grained uniform structure.

Key words: nanopowder, alumina, spark-plasma sintering.

 

New methods of treatment and production of materials
with required properties

E.K. Kazenas, Yu.V. Tsvetkov, V.A. Volchenkova, G.K. Astakhova, O.A. Ovchinnikova

Vapor pressure of oxygen molecules and atoms at oxide dissociation........................................................................................ 78

Generalized results on oxides dissociation of practically all chemical elements are tabulated. Graphics of the

temperature dependencies of the absolute vapor pressure of molecular and atomic oxygen at oxide dissociation

have been presented.

Keywords: oxides of elements, pressure and composition of vapour, molecules, dissociation.

A.M. Orlov, I.O. Yavtushenko, O.G. Rynkova, D.S. Bodnarsky

Kinetics of spark discharges in a liquid electrode....................................................................................................................... 83

Liquid (100% glycerol or 1% aqueous solution of H2SO4) behavior in electric field localized between the positive

polarizable liquid electrode and auxiliary overhanging copper electrode has been investigated. The time of the

growth as well as height of Taylor cone formed in liquid surface are limited by the plasma discharges which

induces a periodic oscillation in the cone height. Effect of the glycerol surface protuberance transformation into

truncated Taylor cone is ascertained. Life time of truncated cone is determined by the duration of Cu electrode

occurrence in polarized state. Kinetics of the cone formation in the surface of liquid electrode as well as

frequency of its alternation are dependent on electrical conductivity and viscosity of the solution, life time of

the spark discharge plasma, and the way of charge accumulation on the face of the auxiliary metal electrode.

Keywords: plasma discharge, Taylor cone, cyclic oscillations, induced charge.