Plasmochemical methods of production and treatment of materials


M.S. Stepanov, Yu.M. Dombrovskii

Mechanism of acceleration of diffusion processes under steel microarc heating........................................................................5

Possible reasons of acceleration of a low carbon steel diffusion saturation during microarc thermo-

chemical treatment have been investigated. Steel specimens imbedded in the container with a coal

powder were heated by electric current passing. Microarc discharges were formed in the powder

environment and concentrated around the specimen surface with formation of the local regions of gas

discharge between the specimen and coal powder. Due to the coal pyrolysis, the carbon containing

atmosphere if formed, and the surface of steel is saturated with carbon. As a result, specimen surface

is coated with Cr and Mo thin layer, and diffusion carbide layer is formed. Diffusion coefficients of Cr

and Mo are calculated. Dependence of diffusion layer thickness on the direction of electric current

(anode heating mode or cathode heating mode) is studied. At anode heating mode, the layer thickness

was 5 times more than the cathode one, alternating current heating gives an intermediate result. At

anode heating, Cr diffusion coefficient is 35 times and Mo diffusion coefficient is 38 times higher than

its values at a furnace heating, and at cathode heating these coefficients were in 2 times less than at a

furnace heating. Previously, alternating current heating gives an intermediate results. Investigations of

the physical processes takes place under microarc heating of steel shows that ions can be affected by the

force of electron wind and the force of electric field. As follows from estimations, the force of

electron wind far exceeds the force of electric field. Hence, foreign ions and atoms are carried away

by conduction electrons in the direction of their movement that leads to acceleration of the process of

steel diffusion saturation under microarc heating.

Keywords: surface steel hardening, microarc thermochemical treatment, acceleration of diffusion

processes at microarc heating.


A.V. Dunaev, D.B. Murin

AFM study of GaAs surface quality after the treatment in freon/argon gas mixture RF plasma...............................................12

Halogen plasma and its mixture with various gases are frequently used for forming a topology on the

semiconductor surface. In this paper, a study of semiconductor structure surface quality after chemical

etching in plasma of freon R12 in argon admixture was carried out. Freon R12 is effectively used for

semiconductors etching, in particular gallium arsenide, achieving an acceptable rate of interaction, while

maintaining a uniform and clean surface. In the technology, mixtures with inert (He, Ar) gas are widely

used, which can act both as a diluent gases and ion sources for ion bombardment of the surface in order to

further stimulate desorption ion interaction products. However, quality control of the samples surface

remains an urgent task of modern electronics. In this paper, the control of the samples surface was carried

out by means of an atomic force microscope Solver-P47Pro. Increase in the bias potential at the substrate

to (61-107) V causes an increase in energy of the particles, in particular argon ions. This leads to an

increase in speed of the ion-stimulated desorption of products of plasma interaction with semiconductor

surface as well as destruction of material surface layers which ensures complete cleaning of the treated

side. It has been shown, that the quality of the semiconductor structure may be controlled by varying the

processing time and the bias potential.

Keywords: freon, plasma etching, atomic force microscopy, gallium arsenide, argon.


S.A. Pyachin

Effects of the electrodes size and positional relationship on a metal transfer under electrospark alloying..............................17

Expression for the coefficient of a metal mass transfer from anode to cathode in the process of electrospark

alloying has been derived depending on electrodes size, interelectrode gap, and positional relationship of

electrodes. The model of metal ejection from the discharge-affected region was proposed arranged by analogy

with the propagation of spherical light waves from a point source of light. One part of the electrical erosion

products is deposited onto the surface of an opposite electrode, and the another part of theirs is removed to

the gas environment. Calculations show that when the meander motion of the anode along the cathode

surface is carried out, the deposition coefficient varies periodically and is decreased at the alloying electrode

approaching to the edge of the substrate. Anode mass Ma and cathode mass Mc are changing during each

discharge owing to competitive processes of electrical erosion and material transfer from an opposite

electrode. If the energy parameters of discharge pulses are constant, dependencies DMa(t) and DMc(t)

on the electrospark pulse duration are almost linear. When the erosion rates of metal electrodes are equal,

the both electrodes lose their mass during electrospark process and mass transfer coefficient possesses

the negative value, and if the anode erosion rate more then twofold greater then that of cathode,

the cathode gain is occurred.

Keywords: spark discharge, electrospark alloying, electrodes, mass transfer coefficient.


Functional coatings and surface treatment


S.V. Loskutov, A.V. Ershov, E.A. Zelenina

Influence of parameters of chemical interaction on adhesion strength of Fe plasma coatings on Fe juvenile surface.............29

The conditions of adhesion of plasma coating particles with a steel substrate surface under plasma

spraying have been considered. Dependencies of the coating adhesion strength on the temperature,

contact time, and thickness of deformed sprayed particles are ascertained. It is shown that the contact

temperature determined by measurement of the sprayed particle temperature is higher than earlier

estimated values but does not reach the substrate melting point. Dependencies of coating adhesion

strength on the contact time and temperature were determined. Theoretical adhesion strength is found

to be more than on order of magnitude higher than real measured values. The reason of decreasing the

experimental adhesion strength is formation of oxide film on the substrate surface Cohesive-oxide

model of the coatingsubstrate adhesion strength is proposed.

Keywords: plasma spraying, substrate, contact temperature, transient heat transfer, adhesion strength.


O.B. Perevalova

Changes in elastic-stress state and phase composition of TiAlN coating under thermocycling................................................34

By methods of X-ray diffraction analysis and transmission electron microscopy, the changes in the

microstructure of magnetron deposited TiAlN coatings after thermal cycling tests (140 cycles) were

investigated. The thermal cycling tests consist heating to 900C and following cooling to room

temperature. Sprayed target was 60 Ti-40 Al (at.%) alloy. Coatings were deposited on the tempered

austenitic steel substrate or on the same substrate after preliminary treatment with Ti ion beam. It was

established that the layer of Ti and Al oxides with microcrystalline structure was formed on the coating

surface during thermocycling. Pressing macrostresses under the oxide layer in TiAlN coating are

decreased, and heterogeneity of Al distribution in Ti1AlN phase is increased. Preliminary treatment

of the substrate with Ti ion beam leads to improvement of the coating thermal stability, diminution of

the oxide layer thickness for the same thermal cycles, and broadening the Al concentration interval in

Ti1AlN phase in the surface coating layers.

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

scanning electron microscopy, energy dispersion analyses of elemental composition, macrostresses.


Composite materials


I.A. Evdokimov, S.A. Perfilov, A.A. Pozdnyakov, V.D. Blank, R.Kh Bagramov,

I.A. Perezhogin, B.A. Kulnitsky, A.N. Kirichenko, V.V. Aksenenkov

Nanostructured composite materials based on Al-Mg alloy modified with fullerene C60...........................................................47

Nanostructured composite materials (NCM) based on Al-Mg alloy AMg6 (1560) modified with

fullerene C60 was obtained by milling of initial materials in a high-energy planetary ball mill and

following hot extrusion of powder mixtures. The structure, phase composition, and physical and

mechanical properties of NCM obtained are studied. It has been shown that introduction of 0.3 wt.%

of fullerene C60 into NCM prevents agglomeration of the particles during milling, intensify the particle

size reduction, and allows to obtain an average aluminum crystallite size less than 50 nm. After

consolidation of the powder mixtures by direct hot extrusion, the obtained materials demonstrate an

increase in tensile strength up to 820 MPa and in bending strength up to 1.11 GPa. Wherein the NCM

density is 2.61 g/cm3, which provides a value of the specific strength on the level of titanium

alloys and fiberglass.

Keywords: composite materials, nanostructuring, fullerene C60, aluminum, milling, extrusion,

powder metallurgy.


New methods of treatment and production of materials with required properties


Yu.N. Toumanov

Electromagnetic technology for synthesis of oxygen-free ceramic high temperature materials:

Scientific and technical principles, technological development.................................................................................................56

Electromagnetic synthesis of oxygen-free ceramic materials, predominantly carbides and borides,

have been implemented on the basis of high frequency inductive heating of a charge of metal oxides

and dis-perse carbon. The first example of this synthesis is obtaining of boron carbide (carbon boride)

from a charge of boron oxide and carbon black. The second product of the synthesis is carbon monoxide;

owing to liberation of carbon monoxide one must press a reacting mass to provide interaction of the

high frequency field with a reacting mass. When high frequency field penetrates into a reacting charge

to the center, one obtains a carbide billet to be uniform on composition and structure. In this case

temperature is uniform along a radius of the cylindrical volume of the reacting charge. To provide the

non-stop interaction of the reacting charge with the electromagnetic field one should add fresh portion

of the charge abd compulsory promote the reacting material from to bottom; this means the continuos

process of synthesis. As a rule, a condensed product constitutes a compressed billet; carbon monoxide

liberates in the form gas flow. Frequency range for the electromagnetic synthesis is within 1 13 MHz;

reactor for synthesis is made of dielectric materials (quarth, alumina, borin nitride) but they possess

with not long operation time. Therefore we developed a combined reactor transparent for high frequency

electromagnetic radiation consistiong of metal water-cooled framework from non-magnetic metal with

longitudinal clearances to be hermetically closed with dielectric inserts. Pilot plant for synthesis

of boron carbide and other carbides according to this technology has been built: it includes a power

source high frequency generator having power of 200 kW, retuning frequency in the range of

1 13 MHz, appliance for transportation, loading and compulsory moving of a charge into the reactor,

an appliance for unloading and cooling of the prod-ucts billets of carbides, a rout for removing of

carbon monoxide.

Keywords: oxygen-free ceramics, carbides, borides, high frequency induction heating, penetration

depth, electromagnetic synthesis, temperature distribution, autocrucible, product yield, carbon,

carbon monoxide, cold crucible.


I.M. Milyaev, V.S. Yusupov, S.Yu. Ostanin, S.I. Stelmashol, A.I. Milyaev, N.V. Laysheva

Magnetic hysteresis and mechanical properties of hard magnetic Fe-27Cr-15Co-2Mo-Si-Ti-V alloy......................................69

Magnetic hysteresis and mechanical properties of a hard magnetic alloy Fe-27Cr-15Co-2Mo-V-Si-Ti

an isotropic and anisotropic state have been investigated with the help of the method of design of

experiments for the purpose of develop a new hard magnetic material with increased values of residual

induction Br (isotropic state) and coercive force HcB (anisotropic state). Optimization of the modes of

heat treatment was performed by the creation of central composite design 23+ star points. Statistical

analysis of the data obtained allows to ascertain the standart Pareto charts for Br, HcB, and (BH)max values

for isotropic and anisotropic alloys. Nonlinear regression equations for dependencies of Br, HcB, and (BH)max

on variation factors were obtained on the base of which an optimal regimes of heat treatment were

determined. Magnetic hysteresis properties of Fe-27Cr-15Co-2Mo-V-Si-Ti alloy have been enhanced

significant after an optimal heat treatment. As a result, a new hard magnetic material on the base of

Fe-27Cr-15Co system is developed. In anisotropic state the values of residual induction, coercive force,

and maximum energy product were amount to Br>1 T, HcB>50 kA/m, and (BH)max>24 kJ/m3 respectively,

whereas in isotropic alloy they were Br ~ 0.8 T, HcB ~ 40 kA/m, and (BH)max > 11,5 kJ/m3. Analysis of

magnetic properties of specimens from the produced pilot batch of anisotropic 27Cr15Co2MSiTiV

magnets in number of 51 pieces shows that yield of magnets with HcB>45 kA/m is 100% and that more

than 50 kA/m is 83%.

Keywords: hard magnetic alloy, residual induction, coercive force, maximum power product,

magnetization, powder metallurgy, thermomagnetic treatment, regression equation, response surface.


V.V. Roshchupkin, M.M. Lyakhovitskii, M.A. Pokrasin, N.A. Minina, E.M. Kudryavtsev

Acoustic properties and microhardness of Cr-Si-Mn structural steel........................................................................................77

The results of experimental study of the temperature dependencies of acoustic properties (velocity and

attenuation coefficient of ultrasound) and relative thermal expansion of structural Cr-Si-Mn steel in the

range of 20-1100C as well as microhardness measurements (20-500C) have been presented.

An investigation of acoustic properties was carried out by means of special acoustic technique distinctive

feature of which is usability of specimens with different size of working section (Russian State Service

of Standard Reference Data, GSSSD ME 216-2014). Measurements of relative thermal expansion of the

steel were carried out with the help of high-speed thermal dilatometer DL-1500-RH. Use of dilatometric

data enhances the accuracy of ultrasound velocity and attenuation coefficient determination and allows

calculate the temperature dependence of the steel density. Steel density value at the room temperature

was measured by hydrostatic weighing method. The Youngs modulus values were calculated.

Microhardness measurements were carried out by continuous indentation method in accordance with

ISO-14577 standard with the help of NanoTest apparatus. Approximate equations for the temperature

dependencies of the thermal and mechanical properties of steel investigated were ascertained as a result

of mathematical treatment of experimental data.

Keywords: structural steel, speed of ultrasound, thermal expansion, density, Youngs modulus,



V.A. Mikitaev, G.V. Kozlov, F.R. Mikitaev

Mechanisms of the structure formation in poly(ethylene terephthalate)/poly(butylene terephthalate) blends..........................83

The blends of poly(ethylene terephthalate)/poly(butylene terephthalate) with widely varied components

relation (from 95/5 to 20/80) were prepared by the method of blending in melt. Estimation of compatibility

of the blends has been carried out by value of parameter k defined in the frame of the model used through

the glass transition temperature of the blend. It was found that k value is varied from 0.31 (system close by

phase division) up to 2.45 (fully compatible blend). It is supposed the amorphous phases of the blend

components are compatible. Parameter k has an extreme dependence on the blend composition with

maximum at about equal content of the components. For explanation of this effect, an analogy of mixing

process and chemical reaction was used in which the density of macromolecular entanglements serves as

analog of conversion degree, and parameter k is characteristic of the rate of formation of these

entanglements. Number of intersection for these coils in interdiffusion zone of components determines

clearly the density of macromolecular entanglements and can be calculated by means of estimation of

a fractal dimension of macromolecular coil in the melt. Comparative analysis of conversion degree

and density of macromolecular entanglements shows that the entanglements are formed only from

equivalent mass fractions of components, but not from whole material of polymer components.

Keywords: polymer blend, miscibility, amorphous phase, equivalent fraction, elastic modulus.