CONTENTS

 

Effect of energy fluxes on materials

 

A.V. Yarovchuk, O.P. Maksimkin, L.G. Turubarova

Corrosion resistance of spent fuel assembly casing irradiated in BN-350 nuclear reactor......................................................... 5

Corrosion damages of the surfaces of casing of fuel assemblies of BN-350 fast nuclear reactor

after operation and long-term (~8 years) storage in water pool have been investigated with the

help of optical and scanning electron microscopy. It was found that corrosion pitting, cavities,

and intergranular cracks are occurred on the surface of 18Cr-10Ni-Ti and 16Cr-11Ni-3Mo steels

after a high-fluence irradiation with neutrons. Investigations of the irradiation-induced changes

in the structure of the steel surface show that enhanced corrosion of austenitic steels takes place

due to its phase instability and liability to martensite ga′ transformation. Laboratory studies of

the effect of neutron irradiation on corrosion resistance of stainless steels were carried out after

irradiation in the WWR-K research reactor. It was ascertained that corrosion resistance of the

steels is depending on the fluence and temperature of irradiation. Neutron irradiation leads to

radiation aging of steels and promotes the martensite ga′ transformation. Appearance of a

martensite phase reduces the corrosion resistance of 18Cr-10Ni-Ti steel and stimulatesthe

intergranular corrosion channels development.

Keywords: corrosion, neutron irradiation, nuclear reactor, stainless steel.

 

Effect of space condition on materials

 

R.H. Khasanshin, L.S. Novikov

Radiation-stimulated changes in glass surface with technological damages............................................................................14

Covering glasses for solar arrays of geostationary satellites have been exposed to the hot

magnetosphere plasma. Separate and combined exposure of glasses by electrons and protons

being the basic components of magnetosphere plasma is accompanied by complicated cross-

coupling processes. To study the electrostatic discharges (ESD) and changes of the structure of

irradiated covering glasses, specimens were selected carefully. However, it remains unclear how

technological defects and possible mechanical damage on the covering glasses that appear when

assembling or transporting the solar arrays influence on development of ESD and changes in the

structure of glass surfaces exposed to radiation. The aim of this work is an experimental study of

the impact of technological defects on the surface of the K-208 type glass used as a protective

coating for solar cells to changes of the surface structure under electron and proton irradiation.

Specimens were irradiated in vacuum chamber with 20 keV protons and 40 keV electrons. The

surface of specimens before and after irradiation was studied with the help of atomic force

microscope. It is ascertained that if the glass is exposed by electrons, the small mechanical

damages like the scratches in the form of chains of microprotrusions on irradiated side are

sufficient to intensify of ESD. The proton irradiation leads to the structures formation on the

glass surface. These structural creations are comparable in size with the technological defects.

Keywords: electron and proton irradiation, K-208 glass, protective coating for solar array,

electrostatic discharges, surface structure.

 

Plasmochemical methods of production and treatment of materials

 

E.A. Bogoslov, M.P. Danilaev, Yu.E. Polsky, I.R. Vakhitov, A.I. Gumarov, I.V. Yanilkin, L.R. Tagirov

Morphology of polymer film coatings produced in a barrier gas discharge at atmospheric pressure....................................... 23

The technique of polymer films deposition from the barrier gas discharge plasma on top of dielectric

substrates is developed. The film precursor is a monomer material highly dispersed in a transport

plasma gas. The plasma formation of the continuous polymer film can be divided into two stages.

The first stage is deposition of liquid monomer droplets with subsequent polymerization on the

dielectric barrier surface resulting in growth of discontinuous film. It is found that the ratio of the

droplets height to their lateral size is almost constant and for polystyrene it is equal to ~0,01. The

second stage is expansion of the droplets into islands and their coalescence into a continuous polymer

film on the dielectric barrier surface. The polymer coating thickness and amount of the cross bonds

essentially depend on the current density and concentration of the monomer in the transport discharge

gas. The continuous polymer film, which is not contaminated with the monomer destruction products,

can be obtained in the current density range (7 25 mA/cm2). Experiments with several monomers,

like methylmethacrylate, styrene and acrylonitrile, have shown that the growth rate is maximal for

monomers with oxygen-free molecules. At the same time, higher growth rate provides low cross-bond

coatings, whereas to get high density of the cross-linked bonds one has to utilize low deposition rates.

The minimal thickness, at which continuity of the film is achieved, increases when the monomer

concentration in the plasma rises. In general, the coating thickness depends linearly with the discharge

current density, the particular figures depend on the type and concentration of the monomer. The

technological parameters are established and given for the three above mentioned monomers.

Keywords: polymer films, barrier discharge plasma.

 

A.S. Tyuftyaev, V.B. Mordynsky, M.V. Ilichev, P.A. Konovalov

An experimental study of the device for a surface plasma treatment of materials.....................................................................29

The heat flux distribution on the sample surface along and across the flat plasma jet with different

widths of the flow transducer was measured using the calorimetry methods. Depending on the shape

and geometric dimensions of the elements of devices for plasma surface hardening the heating

efficiency was calculated. The main reasons for operational damage, for example, of railway wheels

from high carbon steel like 60G is wear of a ridge and defects of contact-fatigue origins. In the

course of frictional interaction of a wheel with a rail in the conditions of swing friction with slipping

elements several types of wear are at work at the same time. It is known that when swinging on rails

the railway wheels are exposed to contact and shock loads, friction between rails and brakes in the

presence of the third body between their surfaces (wear particles, water, sand, lubricant, etc.). In

general, the zone of interaction between a rail and a wheel is characterized by complex tension

conditions; many questions remain open that predetermine the need for further research in this area.

Substantial increase of life cycle of this friction pair is provided by the plasma strengthening surface

treatment of a working part of a wheel flange with a wide plasma strip. As a result of such heating at

the subsequent fast cooling in the surface layer hardened structures are formed varying depending

on the depth of the surface layer. The technology differs from other modes of surface heat treatment

in relative simplicity and low cost of the equipment, and a possibility of the process automatization.

During processing the device is used which includes a plasmatron with the an expanding channel of

an output electrode, and the stream converter which is functionally the hydraulic transitional site in

which the cylindrical stream of plasma from the generator anode will be transformed to a flat stream

on a product surface.

Keywords: friction pair, plasma, plasma jet, flow transducer, plasma hardening, the wheel steel.

 

Functional coatings and surface treatment

 

V.M. Beresnev, O.V. Sobol, A.D. Pogrebnjak, S.V. Litovchenko, S.A. Klimenko, V.A. Stolbovoy,

P.. Srebniuk, .S. Manokhin, M.G. Kovaleva, V.Yu. Novikov, .. Meilekhov,

U.S. Nyemchenko, .. Barmin, P.V. Turbin

Structure and mechanical properties of TiAlSiY vacuum-arc coatings deposited in nitrogen atmosphere................................ 34

Effect of a negative bias potential applied to the substrate on elemental composition, structure, and

mechanical properties of vacuum-arc TiAlSiY nitride coatings have been investigated by different

methods. It is ascertained that applying a high (up to 500 V) bias voltage leads to a selective

sputtering of target as well as significant microdeformation of coating, small-sized crystallites

growth, and theirs preferred orientation along [110] direction. In this case, the coating deposited

has a low hardness H=6.95 GPa and propencity to intense wear under scratch and tribological tests.

Crystallites with stoichiometric composition of ~140 nm in size and [111] preferred orientation

perpendicularly to the surface of growth are formed at the bias potential about 200 V, and

superhard (H=49.5 GPa) and wear-resistant coatings were grown under the such conditions.

Mechanisms of formation of the structure of multi-element coatings are discussed. It is shown

that formation of an amorphous phase and nanocrystal [110] texture takes place at a high bias

potential due to the process of radiation-stimulated selective spraying of target. Formation of 10 nm

sized microstrained crystallites which caused by the weakening of interatomic bonds is observed

in the coating under such deposition conditions, and it leads to the coating hardness decrease and

fast destruction during tribological testing. Substantial bias voltage dependence of deposited

coating properties is established in our investigations.

Keywords: vacuum-arc deposition, wear, friction coefficient, surface, structural engineering, solid solution.

 

G. Abadias, A.Yu. Daniliuk, I.A. Solodukhin, V.V. Uglov, S.V. Zlotsky

Thermal stability of TiZrAlN and TiZrSiN films formed by reactive magnetron sputtering.......................................................44

Quaternary TiZrAlN and TiZrSiN films with Ti:Zr ratio of ~1:1 and different Al (or Si) content

were deposited by simultaneous reactive magnetron sputtering of Ti, Zr and Al (or Si) targets under

Ar+N2 plasma discharges. The elemental composition was determined by WDS and RBS methods,

phase composition has been studied by X-ray diffraction. It was found that the c-(Ti,Zr,Al)N solid

solution of substitution type is the basis of (Ti,Zr)1xAlxN (0.06≤x≤0.65) system. For (Ti,Zr)1xSixN

system (0.13≤x≤0.41), a dual-phase structure is typical comprised by a nanocomposite on the base

of c-(Ti,Zr)N solid solution and grain-boundary amorphous a-SiNy phase. Appearance of the second

a-SiNy phase promotes an amorphization of the films. Vacuum annealing of the films investigated at

the temperatures up to 1000C does not lead to decomposition of the solid solutions which compound

the films. Both rather high deposition temperature (600C) and stoichiometric nitrogen content

can be the reasons for thermal stability of the films. Annealing-induced Al depletion of c-(Ti,Zr,Al)N

solid solution grains is observed in (Ti,Zr)1xAlxN films caused by the growth of AlN based

amorphous phase at the grain boundaries.

Keywords: transition metal nitride, magnetron sputtering, TiZrAlN, TiZrSiN, phase formation,

thermal stability.

 

S.V. Konovalov, V.E. Kormyshev, V.E. Gromov, Yu.F. Ivanov, E.V. Kapralov

Gradient structure in Hardox 450 steel with built-up layer....................................................................................................... 56

Phase composition and defect substructure of the modified layer built-up on Hardox 450 steel with

the wire containing C, Mn, Cr, Nb, W, Fe have been investigated. The high-strength surface layer

having not less than 6 mm thickness and the average microhardness value of 10.2 GPa is formed as

a result of surfacing. With greater distance from the surface of the material into the depth of the

built-up layer the microhardness of the material decreases up to 6 GPa. By methods of transmission

electron microscopy it has been shown that Hardox 450 steel is α-phase based polycrystalline

aggregate. In the grain volume of α-phase the lamellar structure is predominantly observed. In

specific cases α-phase grains with subgrain structure are revealed. The particles of iron carbide

Fe3C are revealed in the volume of plates, at the boundaries of plates and subgrains. It has been

established that the layer built-up on steel is a multiphase material with the main constituent of

α-phase having the martensitic structure. The presence of retained austenite locating in the form

of extended interlayers along the boundaries of martensite crystals has been revealed in the

built-up layer. The formation of the built-up layer is accompanied by the creation of the second

phase inclusions in the form of interlayers, globules and faceted crystals. The inclusions have the

sizes from 0.2 to 1 μm. In most cases they are niobium carbide NbC. In specific cases the reflections

belonging to carbides of chromium and tungsten are revealed on microelectron diffraction patterns.

The structure of built-up layer substrate transition zone is close to the initial steel one according

to the morphological signs. It has been shown that the martensitic structure with chaotically

distributed dislocations and dislocation balls is revealed in the transition zone. The second phase

particles (iron carbide) are revealed at the boundaries of martensite crystals. The carbide phase

particles formed by carbide forming elements of the built-up layer (chromium carbide particles

Cr3C2 and M23C6((Fe, Cr)23C6) have been revealed. The carried out investigations showed that

the structure of the transition layer was similar to that of the initial steel volume according to the

morphological signs. The differences consist in the hardening of the transition layer by the

particles of carbide phases formed by the elements of surfacing wire.

Keywords: steel Hardox 450, welding, defect substructure, phase composition, microhardness

 

 

Composite materials

 

L.K. Bolotova, I.E. Kalashnikov, L.I. Kobeleva, P.A. Bykov, I.V. Katin,

A.G. Kolmakov, N.B. Podymova

Structure and properties of the B83 babbit alloy based composite materials produced by extrusion....................................... 63

Extruded bars of hardfacing B83 babbit alloy reinforced by silicon carbide particles with an average

size of 40 μm and modified with shungite rock (MSR) have been manufactured. Specimens of the

powder mixture of babbit alloy and fillers produced by mechanical alloying were cold pressed,

heated to the temperature of 31010C, exposed at this temperature for 30 min, and then extruded

on a mechanical press at 3205 MPa. The structure, physical, mechanical and tribological properties

of produced composite material (CM) have been studied. An uniform distribution of reinforcing

fillers and changes of the morphology of intermetallic SnSb and Cu3Sn phases with size reduced by

1.5-1.8 times were observed in the specimens produced by extrusion. The values of hardness,

density, and elastic modulus measured by laser photoacoustic method were not worse than these for

the cast B83 babbit alloy. Introduction of SiC and MSR particles into the babbit composition lead to

its strengthening and wear resistance increase by ~20% as compared with the cast material. The best

wear resistance, by 1.7 times greater than for the cast alloy, was obtained in SiC+MSR polyreinforced

CM. This material is characterized by the least variation of the friction coefficients in a whole range

of tribological loading studied and by the most stable process of friction.

Keywords: alloy babbit B83, reinforcing fillers, extrusion, composite rods, structure, optoacoustic

laser method, wear resistance

 

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: Hardware implementation.........................................................................................................................................71

Development and design of the electromagnetic technology for synthesis of oxygen-free ceramic

materials as applied to carbides and borides based on direct high frequency inductive heating of

charge of oxides and disperse carbon are exhibited. Equipment for implementation of the technology

in static, continuous, and discrete-continuous operating modes is elaborated, manufactured and tested

under industrial conditions. Operation analysis and calculation of the metal-dielectric reactor to

be transparent for electromagnetic power flow from a coil are conducted. Technology for

manufacturing of this element is elaborated. The technology proposed was examined under industrial

conditions as applied to synthesis of boron carbide, carbides of silicon, zirconium, lanthanum,

borides of zirconium and titanium. Advantages of the electromagnetic technology are formulated

as compared to the existing scientific and industrial level.

Keywords: electromagnetic technology, high frequency, coil, skin layer, refractory materials

synthesis, carbide, boride, autocrucible, carbon monooxide, metal-dielectric reactor.

 

V.M. Orlov, T.Yu. Prokhorova

Heat treatment of tantalum oxide compound reduction products............................................................................................... 86

Effect of heat treatment of the products of magnesium-thermic reduction of tantalum oxide

compounds (reaction mixture (RM)) on the specific surface and porosity of tantalum powders as

well as characteristics of produced capacitor anodes has been investigated. Relationship between

the powder surface area and the temperature of RM heat treatment was found to have a linear

character. The powder surface can be calculated as Sht =aTht +b, where Sht is a specific surface

area of the powder obtained after RM heat treatment, ht is the treatment temperature, a and b are

calculated coefficients: a = 0.00027S0 + 0.0079, b = 0.417S0 +12.7, S0 is the surface area of powder

obtained from untreated RM. Owing to mesoporous structure of magnesiumreduced powders,

the surface mostly diminishes due to disappearance of the pores with the diameter of less than

10 nm. At the same time, the average size of pores is observed to be growth. Heat treatment of

RM did not bring about increasing of oxygen content in the resulting powders. Its quantity did

not exceed that in natural oxide layer (3 mg/m2). Heat treatment of the reaction mixture opens

up the opportunity to obtain capacitor powders with a high specific charge omitting the

deoxidization stage.

Keywords: tantalum, mesoporous powder, heat treatment.