CONTENTS

 

Effect of energy fluxes on materials

 

A.S. Dikov, I.I. Chernov, S.B. Kislitsin

Effect of test temperature on the creep rate of Cr-Ni structural steel irradiated in BN-350 nuclear reactor.............................. 5

During the preparation of spent fuel assemblies (SFA) of fast neutron reactor BN-350 for a

long-term dry storage, it was found that some cases of SFA have cracks in the upper part of

a number of spent fuel assemblies. Results of the mechanical properties and thermal creep tests

of steel 0.12C18Cr10NiTi preliminary irradiated in fast reactor BN-350 are presented as applied

to durability of structural materials for a long-term storage of spent nuclear fuel. Specimens for

investigation were cut from the facets upper part of the sheath at distance +900 mm from the

reactor core center transversely with respect to its axis direction. Irradiation conditions of the

specimens were the following: Tirr≈400C, fluence is 2-3 dpa, dose rate is ~0.5108 dpa/s.

Tests temperatures are 350 and 450C. It is shown that under mechanical testing at 450C,

increase in strength properties as well as decrease in elongation take place. The effect observed

may be caused by reverse a′→g transition occurring in preliminary irradiated steel at 450C.

It was found that increasing the test temperature from 350 to 450C leads to steadystate creep

rate increase in ~3.7 times and simultaneous decrease in the number and size of carbide

inclusions under the action of a long-term temperature action. It is concluded that the decrease

in the grain size, refinement of carbide inclusions, and carbide particle attenuation during

post-irradiation thermal creep test of the steel can be cause of the creep rate acceleration and,

consequently, dry storage life of spent fuel assemblies shortening.

Keywords: austenitic steel 0.12C18Cr10NiTi, neutron irradiation, mechanical properties, thermal creep.

 

Plasmochemical methods of production and treatment of materials

 

N.V. Kholodkova, I.V. Kholodkov, S.A. Smirnov

Recombination of O(3P) atoms on the surface of stainless steel film in oxygen plasma............................................................ 12

The recombination process of oxygen atoms on surface of stainless steel thin film has been

investigated in positive column of DC glow discharge in oxygen at gas pressure of 50-400 Pa

and discharge current of 20, 50 mA. The probability of heterogeneous recombination of atoms

O(3P) on the film surface of the stainless steel 121810T has been determined. The average

value of the probability of heterogeneous recombination in the pressure range 50-400 Pa is 0,015.

The investigation of the film surface of the stainless steel by atomic force microscopy has been

showed no significant changes in the average roughness of the film surface at the time of oxygen

plasma treatment up to 30 minutes. It has been found that the probability of heterogeneous

recombination of atoms O(3P) has been decreased with the growth gas pressure in the system in

the pressure range 50-200 Pa, which is due both to a simultaneous decrease in the intensification

of the purification process of the active centers by reducing the flow of positive molecular

oxygen ions and by reducing the number of free adsorption centers and difficulty of migration

of adsorbed atoms as a result of increasing the concentration of O2 molecules.

Keywords: heterogeneous recombination, stainless steel, oxygen, film, surface.

 

G.R. Rakhmatullina

Plasma modification of polymers................................................................................................................................................ 18

Effect of the treatment in a non-equilibrium low-temperature plasma on the structure of acrylic

and polyurethane polymers used as a coating of natural leather was studied by IR spectroscopy,

X-ray diffraction and thermal analysis methods. Liquid polymers in the form of aqueous dispersed

solutions were dried to obtain the solid films. Liquid suspensions prior to drying and solidification,

or already solidified solid films were undergone by plasma modification. It is established that

a short-term (3 min) treatment of solid polymers in a HF plasma leads to an improvement in the

mechanical properties of the films. Optimum regimes of plasma treatment are determined. It is

shown that the maximum treatment effect for the acrylic polymer RodaKrulK 577 is achieved

at a capacitive discharge of 0.7 kW (65% increase in strength and 35% in elongation), and for

polyurethane RodaPurK 8727 at a discharge power of 0.1 kW (increase in strength by 170%

and in relative elongation by 72%). The improvement of mechanical characteristics is associated

with conformational changes in the structure of solid polymers resulting in additional

polymerization of it. Changes in the chemical composition of polymers after plasma

treatment have not been detected.

Keywords: plasma, polymers, structuring, thermal analysis, mechanical properties.

 

A.V. Kolomeychenko, V.N. Logachev, N.V. Titov

Increase of machine components life by plasma electrolytic oxidation..................................................................................... 25

Physical and mechanical properties of oxide ceramic coatings formed by plasma electrolytic

oxidation (PEO) on aluminum alloys have been investigated. PEO coatings were produced in

anode-cathode mode of the unit work with a ratio of amplitudes of cathode and anode currents

IC/IA=1.0 with the use of silicate-alkaline electrolyte -Na2SiO3. It is ascertained that the best

properties have the PEO-coatings on deformed duralumin alloy. Wear resistance of the

PEO-coatings working in sliding joints steelPEO-coating with porosity of 3-4%,

steelPEO-coating with porosity of 14-15%, steelPEO-coating with porosity of 14-15%

filled with oil, and steelPEO-coating with porosity of 3-4% and copper layer have been

studied. Coatings modification methods by means of the pores filling with oil or copper layer

applying on the coating surface are proposed. Oil filling and copper layer deposition techniques

enhance the wear resistance of PEO-coatings working in sliding joints of steelPEO-coating

in 1.7 and 4.5 times respectively. On the basis of investigations carried out, a combined method

of machine components repair with the use of PEO technology has been developed for its

life increasing.

Keywords: restoration, hardening and coating, flexible connection, plasma electrolytic oxidation,

thickness, hardness, wear resistance, resource.

 

Functional coatings and surface treatment

 

A.A. Sivkov, D.Yu. Gerasimov

Plasma deposition of Ti-C-N coatings in air.............................................................................................................................. 33

Possibility of production of Ti-, N-, and C-containing superhard coatings on a metal substrate

by plasma-dynamic method in air has been studied. The coating is deposited in time of one short

operation cycle of magneto-plasma accelerator under the impact of a high speed electric discharge

Ti-containing plasma jet on the substrate surface. Formation of TiN and TiCN nanostructured

layers in the coating structure is ascertained with the help of SEM and X-ray diffraction methods

and it leads to the coating hardness increasing. Formation of gradient layer of mixed material at

coating/substrate interface is found to be occurred under the action of high-enthalpy plasma jet

on a metal substrate. The value of hardness is not constant throughout the coating thickness and

ultra-high nanohardness values >20 GPa were obtained for the subsurface layer and

substrate/coating interface region. Mean value of hardness of coating is 16.2 GPa. The

coating produced has a good adhesion with the substrate.

Keyword: coaxial magneto-plasma accelerator, titanium nitride, titanium carbonitride,

superhard coatings.

 

Yu.F. Ivanov, O.L. Khasanov, M.S. Petyukevich, G.V. Smirnov, V.V. Polisadova,

Z.G. Bikbaeva, A.D. Teresov, M.P. Kalashnikov, O.S. Tolkachov

Structure and properties of the surface layer of B4C ceramics treated by high-current pulsed electron beam......................... 38

The structure transformations and properties of the surface layer of 4 ceramics treated by

high-current pulsed electron beam have been investigated with the help of TEM, SEM and

X-ray analysis. Ceramics specimens were obtained by SPS of 4 submicron powder with

the addition of 10 wt.% of 4 nanopowder. Specimens irradiation with high-intensity pulsed

electron beam was carried out on SOLO installation at the following operating parameters:

electron energy U=15 keV, energy density of electron beam is 5-30 J/cm2, pulse duration 100 μs,

pulse repetition rate 0.3 s1. It is shown that irradiation of sintered 4 ceramics by intense

pulsed electron beam leads to the formation of pore-free surface layer with polycrystalline

structure and initiates the process of fine-scale twinning and extended layer crystallites

formation along the boundaries of grains with submicro- and nanocrystalline structure.

These structure transformations increase the fatigue life of the modified layer. An optimal

mode of electron-beam treatment of B4C ceramics is ascertained.

Keywords: boron carbide, ceramics, intense electron beam, irradiation, structure, properties.

 

G.A. Pribytkov, V.I. Kalita, D.I. Komlev, V.V. Korzhova, A.A. Radyuk, A.V. Baranovsky,

A.Yu. Ivannikov, M.G. Krinitcyn, A.B. Mikhailova

Structure and wear resistance of plasma coatings sprayed by TiC+HSS binder composite powders....................................... 45

An elemental and phase compositions, macro- and microstructure, hardness and wear resistance

of plasma sputtered coatings has been investigated. A high speed steel (HSS) powder and

TiC+HSS binder composite powder were used for sputtering of the coatings.

The TiC+50 vol.% HSS binder composite powder was produced by self-propagating high

temperature synthesis. It was found that the coatings phase composition does not differ from

that of the sprayed powders. At the same time, ferrite to austenite ratio in initial steel binder

and in sprayed coatings can alter due to different cooling rates at the powder production

and at the coatings spraying. Another reason of the steel binder phase composition change

in metal matrix composite is an influence of titanium carbidesteel binder interaction. Carbon

depletion and simultaneously oxygen and nitrogen absorption occur during plasma spraying

of powders. Carbon depletion is 38 and 14% at the spraying of steel and composite powders

respectively. Oxygen content in the coatings is 29 and 3.5 times more than that in steel and

composite powders. Nitrogen content in the coatings is 3.5 and 16.8 times more than that in

steel and composite powders. According to X-ray diffraction date, titanium carbide lattice

absorbs most of nitrogen. It was found that a dispersion, morphology, and volume content

of titanium carbide inclusions in metal matrix structure of the composite powder are retained

in the deposited coating. That is an important advantage of titanium carbide base metal matrix

composites over tungsten carbide base composites. As a result, hardness of plasma sprayed

titanium based composite coatings increased twice and wear resistance increased 7.6 times

as compared with that of the coatings sprayed by the HSS powder.

Keywords: self-propagating high-temperature synthesis, plasma sputtering, metal matrix

composite, structure, hardness, wear resistance.

 

Composite materials

 

A.F. Dresvyannikov, E.V. Petrova, A.I. Khairullina

Physicochemical behavior of SPS compaction of high-disperse alumina-zirconia systems

fabricated by electrochemical methods...................................................................................................................................... 56

The process of spark plasma sintering (SPS) of Al2O3 and Al2O3-ZrO2 fine-grained powders

produced by electrochemical method with required morphology, chemical and phase

composition has been studied. The particles of these precursors have a platelet or spherical

shape, size of 50-300 nm, and combined into agglomerates. It is established that nanoparticles of

the system of Al2O3-ZrO2 obtained by electrochemical method are characterized by stability of

t-ZrO2 phase up to 1100C. Calcination of material in the temperature range of 1200-1400C

shows CSR growth for m-ZrO2, t-ZrO2, and a-Al2O3 phases in ~1.4 times. The grain size of

dispersed Al2O3-ZrO2 system is slowly increased during SPS process indicating thereby on the

grain stabilization at high temperatures. Compact SPS (1250C, 5 min, 60 MPa) specimens

have a high microhardness values ~20.0 GPa. At 1250-1300C, flexural strength of the bulk

specimens is decreased with increasing the content of the monoclinic phase of zirconia. Phase

transformation causes a deterioration of microstructure and development of stress concentrators

in ceramics. The highest flexural strength values of bulk specimens are reached at the

temperatures of 1300-1400C due to high density of specimens. It is ascertained experimentally

that the ratio of t/m-ZrO2 phases is preserved in the temperature range of

1250-1400C when the grain size is increased slightly.

Keywords: alumina-zirconia oxide system, spark plasma sintering, phase composition,

morphology, electrochemical synthesis.

 

A.A. Banishev, A.F. Banishev

Peculiarities of photoluminescence and mechanism of mechanoluminescence of composite materials

on the base of photopolymerizing resin and fine-dispersed powders of SrAl2O4:(Eu2+,Dy3+)

and Sr4Al14O25:(Eu2+,Dy3+,B) luminophores............................................................................................................................ 64

The spectra and kinetics of photoluminescence of fine-dispersed powders of SrAl2O4:(Eu2+,Dy3+)

and Sr4Al14O25:(Eu2+,Dy3+,B) phosphors have been investigated. Some lasers with different

wavelengths (λ=355, 404, 440 and 530 nm) were used for the photoluminescence excitation.

The materials investigated photoluminescence in a long-wave range of 550-750 μm is

ascertained, and it is considered as an evidence of the presence of radiation spectrum due to

radiative transitions between the energy levels occurred. The structure of the powders is

studied with the help of scanning electron microscope. It is found that these powders are

consist of 100 μm microparticles (granules) with the grain size up to 25 μm. It is concluded

that mechanoluminescence of SrAl2O4:(Eu2+,Dy3+) and Sr4Al14O25:(Eu2+,Dy3+,B) powders

is excited due to the tramp activation during their interaction with the electric fields of moving

grain boundary dislocations under grain boundary sliding in the process of the microparticles

deformation under shock loading.

Keywords: photoluminescence, mechanoluminescence, fine-dispersed powders of

SrAl2O4:(Eu2+,Dy3+) and Sr4Al14O25:(Eu2+,Dy3+,B), photopolymer, composite material.

 

New methods of treatment and production of materials with required properties

 

A.V. Makunin, N.G. Chechenin, E.A. Vorobyeva, D.A. Pankratov

Formation of axial aligned polydisperse nanocarbon structures under gas-pyrolytic deposition

from cyclohexane with ferrocene................................................................................................................................................ 72

Vertically aligned arrays of multiwall carbon nanotubes have been deposited on a single crystal

silicon substrate by CVD method from cyclohexane with ferrocene as a catalyst. As a result of

synthesis the axial polydisperse carbon microstructures combined from vertically aligned carbon

nanotubes were produced. The structures investigations were carried out with the use of SEM

Tescan Lyra3 FEG, Ntergra Spectra NT-MDT probe microscope, and Raman scattering method.

The possibilities of purification of synthesized carbon structures from amorphous carbon by

oxidation with atomic oxygen and ozone have been studied with the purpose of significantly

increasing their specific surface area. Methods for the use of synthesized polydisperse

structures as carriers of catalysts, solid electrolytes, carriers of chemical sensors, and also

in absorption techniques for storing gases and liquids are proposed.

Keywords: carbon nanotubes, aligned arrays, synthesis, substrate, silicon, electronic

microscopy, probe microscopy, Ramanspectroscopy, specific surface, phase carrier.

 

D.A. Korotkov, S.V. Korotkov, G.L. Spichkin, L.M. Fedotova

Application of high-voltage nanosecond discharge for the control of proliferation of fibroblast cells

on the surface of fluorine-carbon polymer implants...................................................................................................................79

The possibility of modifying the surface of film implants from porous fluoroplastic by their

treatment in a low-temperature plasma of a high-voltage discharge of nanosecond duration

was investigated. As the specimens, films for reconstructive surgery (FRS) and films for the

replacement of bone defects (FRBD) from polytetrafluoroethylene (PTFE) were used. Duration

of the plasma treatment of specimens ranged from 1 to 10 s. The surface quality of the films

was estimated using an atomic force microscope by their roughness and hydrophilic behavior.

It is established that plasma treatment significantly increases the surface roughness which is

associated with a change in its structure. The degree of hydrophilicity of the surface of FRS

and FRBD films was determined from the angle of rolling of the drop of water and it is depended

on the initial state of the surface (the smooth or corrugated side of specimen), the gas discharge

gap width and on the duration of plasma treatment. A correlation was found between the angle

of rolling of a drop of water and the proliferative capacity of sown cells: the larger the angle of

rolling, the higher the density of cells was observed on the surface. It is established that plasma

treatment practically does not affect the mechanical strength of the films and ensures the sterility

of the films within 28 days after the 1 second plasma treatment.

Keywords: fluorocarbon polymer implants for reconstructive surgery and replacement of

tissue defects, high-voltage nanosecond volume discharge, low-temperature plasma, surface

modification, hydrophilic behavior, fibroblast cells, plasma sterilization.

 

V.Yu. Zufman, S.V. Shevtsov, A.I. Ogarkov, I.A. Kovalev, R.B. Kuznetsov, A.A. Ashmarin,

N.A. Ovsyannikov, N.N. Dergunova, S.K. Rodionova, A.S. Chernyavsky, K.A. Solntsev

High-temperature oxidation of copper using oxidative constructing approach......................................................................... 86

Kinetics of oxidation of copper in the temperature range of 600-1000C has been studied in

the frame of materials oxidative constructing approach. The structure and phase state of

oxidized layer was investigated. It is found that in the temperature range studied the kinetics

of copper oxidation is described by a parabolic law. Resultant compact oxide ceramics has

an uniform thickness and the structure of near the surface oxide layer is represented by

tenorite phase while the main bulk is composed of cuprite phase. At 600 and 700C surface

layer has a polycrystalline needle-shaped grain structure. It is ascertained that oxide Cu2O

is formed on the flat surface at 700 and 800C on which has a good adhesion to the surface

and is optically transparent in the visible light spectrum.

Keywords: copper, tenorite, cuprite, oxidative constructing, oxidation, kinetics, structure.