Pages 559 666 3NMHT

3rd International Conference on New Materials and High Technologies

Chairman Alexey Markov, Tomsk Scientific Center SB RAS, Tomsk, Russia Co-Chairman Yuri Maksimov, Tomsk Scientific Center SB RAS, Tomsk, Russia Program Chairman Alexey Markov, Tomsk Scientific Center SB RAS, Tomsk, Russia Program Co-Chairman Yuri Maksimov, Tomsk Scientific Center SB RAS, Tomsk, Russia

Program Committee Sergey ZELEPUGIN Tomsk Scientific Center SB RAS, Tomsk, Russia Alexander KIRDYASHKIN Tomsk Scientific Center SB RAS, Tomsk, Russia Yuri MAKSIMOV Tomsk Scientific Center SB RAS, Tomsk, Russia

International Advisory Committee Mikhail ALYMOV Merzhanov Institute of Structural Macrokinetics and Materials Science RAS, Chernogolovka, Moscow Region, Russia Alexander BARDENSHTEIN Danish Technological Institute, Taastrup, Danish Massimiliano BESTETTI Politecnico di Milano, Milan, Italy Fengchun JIANG Harbin Engineering University, Harbin, P.R. China Alexander KIRDYASHKIN Tomsk Scientific Center SB RAS, Tomsk, Russia Irina KURZINA Tomsk State University, Tomsk, Russia Nikolay LYAKHOV Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia Zulkhair MANSUROV Institute of Combustion Problems, Almaty, Kazakhstan Sergei MINAEV Far Eastern Federal University, Vladivostok, Russia Nahum TRAVITZKY Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany Zbigniew WERNER National Center for Nuclear Research, Otwock, Poland Sergey ZELEPUGIN Tomsk Scientific Center SB RAS, Tomsk, Russia

Conference topics Non isothermal methods for materials synthesis Combustion waves: theory and experiment Functional materials and coatings

______Non isothermal methods for materials synthesis COMPARATIVE ANALYSIS OF THE STRUCTURE AND INTERNAL STRESS IN TI-6AL-4V ALLOYS MANUFACTURED BY 3D PRINTING AND PROCESSING WITH SCREW EXTRUSION1

N.V.KAZANTSEVA*, I.EZHOV*, N.I.VINOGRADOVA*, A.S.FEFELOV**, MERKUSHEV A.**, ILYINIKH M.**, A.E.VOLKOV*** * Institute of Metal Physics, 620990, Ekaterinburg, Russia, [email protected] ** Regional Engineering Center of laser and additive technology, 620078, 61, Komsomolskaya Str., Ekaterinburg, Russia ***Scientific and Production Company Ruteni Ltd., 620075, 85/212, Mamina Sibiraka Str., Ekaterinburg, Russia

One of the main tasks of modern developments in the production of titanium alloys is the expansion of the spectrum of metal properties using various processing methods. It is known that metals subjected to strong deformations can acquire completely new properties, most of which can be of practical interest. For example, it may combine high plasticity with great strength. The method of reverse and comprehensive extrusion with the use of screw extrusion includes several stages of ingot processing [1]. Figure 1 shows one of the stages. Additive technology is a novel surface engineering technique, which allows us to obtained Ti-6Al-V alloys with high density (about 99.9%) as cast materials [2]. In this report, we present the comparative study of the Ti-6Al-4V alloys manufactured by 3D printing and processing with screw extrusion. Horizontal Ti-6Al-4V samples were produced by the EOSINT M280 machines (EOS GmbH) equipped with an Ytterbium fiber laser operating at 1075 nm wavelength (IPG Photonics Corp.). We examined the industrial Ti-6Al-4V samples after the first twisting and after pressing the twisted sample into a round washer. According to structural studies, the deformed alloy retains a two-phase state. After the first twisting in the sample, a change in the intensity of X-ray diffraction lines indicating the presence of the texture is revealed. The grain size in the sample after pressing decreases by about half compared to the sample after pressing. It is known that 3D printing of the titanium alloys produces the samples with non-equilibrium structure with high level of internal stresses. TEM studies of 3D samples showed the martensitic structure without any  precipitations.

Fig. 1. Fig.1. Pressing a twisted blank into a washer Estimation of residual internal stresses in the studied samples and comparison with obtained data on influence of severe plastic deformation by screw extrusion is provided. REFERENCES [1] A.E. Volkov // Journal Titan.  2015.  1.  № 47.  35-38. [2] P. Krakhmalev, G. Fredricsson, I.Yadroitseva, N. Kazantseva, A. Du Plessis, I.Yadroitsev, // Physics Procedia.  2016.  83.  778 – 788.

1 This work was supported by Russian Found of Basic Research N 17-03-00084

561 ______Non isothermal methods for materials synthesis MAIN FACTORS AFFECTING THE STRUCTURE AND PROPERTIES OF TITANIUM AND COBALT ALLOYS MANUFACTURED BY THE 3D PRINTING1

N.V. KAZANTSEVA Institute of Metal Physics, 620990, Ekaterinburg, Russia, [email protected]

Development of techniques for manufacturing finished parts from titanium alloys using additive technologies are relevant at present for both scientific and industrial purposes. Methods of 3D printing are very promising, especially for medicine, because they allow you to obtain details of complex designs and take into account the personal characteristics of the human body. When constructing parts in installations using additive technologies (selective laser fusion, selective laser synthesis, electron beam fusion), a number of characteristics are important, including the parameters of the used installation (for example, laser power), the quality and size of the powder, the distance between layers, substrate surface quality, substrate temperature, etc. [1-2]. All of this will affects the porosity, the level of residual stresses and the structure of the material, which, accordingly, determines its mechanical properties [3-4]. Additive technology is a novel surface engineering technique, which allows us to obtained Ti-6Al-V alloys with high density (about 99.9%) as cast materials [2]. The report considers the main factors affecting the structure and properties of titanium alloys Ti6Al4V and CoCrMo alloys, obtained by additive methods. A comparative analysis of the structure and properties of Ti6Al4V or CoCrMo alloys obtained using various 3D printing techniques is presented. REFERENCES [1] E. Gordon, V. Dhokia, // Proceedings of the 13th International Conference on Manufacturing Research (ICMR2015). 2015. 1-6. [2] P. Krakhmalev, G. Fredricsson, I.Yadroitseva, N. Kazantseva, A. Du Plessis, I.Yadroitsev, // Physics Procedia.  2016.  83.  778 – 788. [3] I. Yadroitsev, P. Bertrand, I. Smurov // Applied Surface Science. 2007. 253(19). 8064–8069. [4] L. E. Murr, S. M. Gaytan, F. Medina2, E. Martinez, D. H. Hernandez L. Martinez M. I. Lopez, R. B. Wicker and S. Coll // Proceedings of Solid Freeform Fabrication Symposium. 2009.  374-394.

1 This work was supported by Russian Found of Basic Research N 17-03-00084 and State assignment on the topic "Diagnostics" №АААА-А18- 118020690196-3

562 ______Non isothermal methods for materials synthesis HIGH-ADHESION COATINGS – SURFACE ALLOYS FORMED BY LOW ENERGY HIGH CURRENT ELECTRON BEAM: PROPERTIES AND APPLICATIONS

A. MARKOV*, E. YAKOVLEV*, V. PETROV**, D. SHEPEL**

* Tomsk Scientific Center SB RAS, 10/4, Akademicheskii pr., Tomsk, 634055, Russia ** Institute of High Current Electronics SB RAS, 2/3, Akademicheskii pr., Tomsk, 634055, Russia

Surface alloys are the high-adhesion coatings of controlled composition fused with a metallic substrate by concentrated energy fluxes. “RITM-SP” is electron-beam machine equipped by a magnetron sputtering system enabling the formation of surface alloys of required thickness [1-2]. The process of formation of surface alloys consists of the deposition of films on a treated substrate followed by a liquid- phase mixing of the deposited film and the substrate upper layer with a LEHCEB in a single vacuum cycle or in other words without breaking vacuum. The thicknesses of the resulting surface alloys may vary from tenths to tens of micrometers. In the work some examples of application of electron-beam machine RITM-SP for formation of surface alloys are given. The alloys investigated were Cu-Cr and Ag-Brass. The purpose of their formation was to enhance the mechanicals and electrical properties. SEM, TEM, optical microscopy, XRD, and element analysis were used for characterization of synthesized surface alloys. Tribological tests were carried out according to the "pin-on-disc" scheme with the TRIBOtester device (France). As a counterbody, a ball made of 100Cr6 steel of radius of 3 mm was used. The load was 2 N, friction path of 40 m, track radius of 2 mm, and a sliding speed of 25 mm/s. The tests were carried out under normal conditions without a lubricant. . REFERENCES [1] Markov A.B., Mikov A.V., Ozur G.E., Padei A.G. // Instrument and experimental techniques. − 2011. − Volume 54. Pages 862- 866. [2] D. Luo, G. Tang, X. Ma, L. Gu, L. Wang, T. Wu, F. Ma // Vacuum. − 2017. − Volume 136. Pages 121-128.

563 ______Non isothermal methods for materials synthesis FAILURE OF THE MIL COMPOSITES UNDER SHOCK WAVE LOADING1

S.A. ZELEPUGIN, A.S. ZELEPUGIN, A.A. POPOV, D.V. YANOV Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Avenue, Tomsk, 634055, Russia, [email protected], +7(3822)492294 National Research Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia, [email protected], +7(3822)492294

The field of material microstructure design targeted for a specific set of structural and functional properties is now a recognized field of focus in materials science and engineering. A new class of structural materials called metallic-intermetallic laminate (MIL) composites can have micro-, meso- and macrostructure. The superior specific properties of this class of composites make them attractive for high- performance ballistics applications [1, 2]. In this work the processes of high-velocity interaction of a projectile with a multilayer MIL composite target were numerically investigated in axisymmetric geometry using the finite element method. The set of equations for describing unsteady adiabatic motion of an elastoplastic medium, including nucleation and accumulation of microdamages and temperature effects, consists of the equations of continuity, motion, and energy. To numerically simulate the failure of the material under high velocity impact, we applied the active- type kinetic model determining the growth of microdamages, which continuously changes the properties of the material and induce the relaxation of stresses. The strength characteristics of the medium (shear modulus and dynamic yield strength) depended on temperature and the current level of damage. The critical specific energy of shear deformations was used as a criterion of the erosion failure of the material that occurs in the region of intense interaction and deformation of contacting bodies. To simulate the brittle-like failure of the intermetallic material under high velocity impact, we modified the kinetic model of failure and included the possibility of failure above Hugoniot elastic limit (HEL) in the shock wave and sharp drop in strength characteristics if the failure begins.

a b

Fig. 1. Computer images with a radial section of the projectile/target assembly (a) and specific volume of microdamages (b) at 60 μs

In the computations, the target consisting from 17 composite intermetallic Al3Ti - titanium alloy Ti-6-4 layers has been used. Total thickness of the target was 19.89 mm. Thicknesses of intermetallic layer and a layer of titanium alloy were varied. The penetrator used was a tungsten heavy alloy 93W-7FeCo rod with initial diameter of 6.15 mm and length of 23 mm. Initial impact velocity was of 900 m/s. Fig. 1 shows the configurations of the projectile and MIL composite target and the contours of the specific volume of microdamages at the time of 60 µs. Results of computations demonstrate that destruction of the intermetallic layer is brittle as against to plastic failure of the metal layer. The intermetallic layer provides the failure of the projectile and the metal layer terminates the propagation of damage. The results show that the depth of penetration depends on the thicknesses of intermetallic and titanium alloy layers. The composite target withstands the impact loading in the case of the ratio about 4/1 (Al3Ti / Ti-6-4). REFERENCES [1] Cao Y., Zhu S., Guo C., Vecchio K.S., Jiang F. // Applied Composite Materials. - 2015. - Vol. 22. - P. 437–456. [2] Zelepugin S.A., Mali V.I., Zelepugin A.S., Ilina E.V. // Shock Compression of Condensed Matter. USA: American Institute of Physics. - 2012. - Vol. 1426. - P. 1101-1104.

1 This work was supported by the Russian Science Foundation (RSF), project no. 16-19-10264.

564 ______Non isothermal methods for materials synthesis

PROBLEMS OF SOLID-PHASE SYNTHESIS UNDER EXPLOSIVE LOADING O.V. IVANOVA*, S.A. ZELEPUGIN*, A.S. YUNOSHEV**, A.S. ZELEPUGIN* *Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634055, Russia, [email protected], +7(3822)492294 **Lavrentyev Institute of Hydrodynamics of SB RAS, 15 Lavrentyev Ave., 630090, Novosibirsk, Russia

At present, the processes connected with mechanical and physical and chemical transformations which occur when shock waves propagate through metals, minerals, polymers, and other solids attract close attention of researchers. Synthesis of new materials conducted under equilibrium conditions is practically exhausted. Perspectives are associated with the obtaining of metastable compounds under nonequilibrium conditions, and explosive loading provides great opportunities for this purpose. It should be noted that the potential of explosive loading has not been studied thoroughly yet, and so far this direction has not become a technology due to the lack of experimental data and numerical multicomponent medium models which can consider the cumulative effect of mechanical, chemical and physical processes and estimate the role of each factor. During explosive loading of recovery ampoules with reacting multicomponent mixtures, there is a significant energy release due to exothermic reactions, which, on the one hand, can lead to a self-sustaining propagation of chemical reactions in mixtures and, on the other hand, to the failure of ampoules, as well as to the complete fracture [1]. It is necessary to mention that the initiation and development of shock-induced reactions are determined not only by the temperatures reached but also by the dispersion and porosity of initial components. In addition, the initial dispersion of components can contribute to the fracture of the cylindrical ampoule. In the work, the process of solid-phase synthesis was studied using aluminum-sulfur and aluminum- fluoroplast mixtures placed in a cylindrical ampoule under explosive loading on the basis of a mathematical multicomponent medium model developed to predict the behavior of reacting mixture, taking into account the porosity and dispersion of mixture components [2]. The analysis of numerical and experimental results allows us to conclude about the contribution of the porosity and dispersion of mixtures to the dynamics of shock wave propagation and the development of chemical reactions during solid-phase synthesis in cylindrical ampoules under explosive loading. During the propagation, a shock wave, reflected from the bottom of the ampoule in the form of a compression wave, encounters the shock wave propagating in the sample, which leads to a sharp increase in the pressure and the rate of chemical reactions in the low and middle part of the sample. It should be noted that the reaction in the high dispersion Al/S mixture is complete with the formation of aluminium sulfide (100%). Despite the sharp increase in pressure and temperature, not all the low dispersion mixture components react to form aluminium sulfide. The contribution of high pressures and temperatures is not sufficient for the complete reaction in the low dispersion mixture. The experimental and numerical results have shown that the higher the initial dispersion and porosity of the mixture components, the more intensive the ampoule fracture. In some experiments, there was a complete fracture of the ampoule. The experimental and numerical studies have revealed the problem connected with the fracture of ampoules containing reacting porous multicomponent mixtures under explosive loading, which urgently requires conducting the further studies to solve this problem.

REFERENCES 1. Zelepugin S., Ivanova O., Yunoshev A. and Zelepugin A. Destruction of cylindrical ampoules containing solid phase reaction mixtures under explosive loading // Letters on materials.-2015.-V.-5(4).-P. 468-472. 2. Ivanova O., Zelepugin S., Yunoshev A., Silvestrov V. A Multicomponent Medium Model for Reacting Porous Mixtures under Shock Wave Loading // Journal of Energetic Materials.- 2010.- V. 28 (1). – P. 303-317.

565 ______Non isothermal methods for materials synthesis

HIGH-ADHESION COATINGS – SURFACE ALLOYS FORMED BY LOW ENERGY HIGH CURRENT ELECTRON BEAM: PROPERTIES AND APPLICATIONS

A. MARKOV*, E. YAKOVLEV*, V. PETROV**, D. SHEPEL**

* Tomsk Scientific Center SB RAS, 10/4, Akademicheskii pr., Tomsk, 634055, Russia ** Institute of High Current Electronics SB RAS, 2/3, Akademicheskii pr., Tomsk, 634055, Russia

566 ______Non isothermal methods for materials synthesis

MECHANICAL ACTIVATION AND THERMAL EXPLOSION IN TI-NI AND NB-SI SYSTEMS

O. A. SHKODA, O. V. LAPSHIN

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], +7(3822)492294

Mechanical activation (MA) is an effective method to increase the reactivity of condensed substances and expand significantly the possibilities of material synthesis [1, 2]. This method is widely used for the synthesis of low-energy compounds which practically do not burn under the typical conditions of synthesis. During MA, the particles of reacting components are pumped with additional (excess) energy that reduces the activation barrier of chemical reactions. Another important factor that accelerates the formation of reaction products during MA is the grinding of substances and the formation of mechanocomposites (particles), the interphase surface of which is substantially increased [3, 4]. This work provides the experimental and theoretical studies of two-stage mechanochemical synthesis in metal-metal and metal-nonmetal systems. The Ti-Ni and Nb-Si systems are considered to be examples. The studies conducted show that the preliminary mechanoactivated Ti + Ni mixture does not contain reaction products. However, the intensive formation of mechanically synthesized silicides was observed during the mechanical treatment of the Nb + 2Si mixture. The dynamics of mechanochemical synthesis is studied. The results have shown that preliminary mechanoactivation intensifies chemical transformations, reduces the ignition temperature and the maximum synthesis temperature at the stage of thermal explosion and contributes to the transition of chemical interaction with the participation of liquid phase into the solid-phase regime (without melt formation) in the Nb-Si system. Thermokinetic and thermophysical constants determining the mechanochemical synthesis of TiN and

NbSi2 products are calculated using the experimental data and the inverse method. The optimal regimes are found for the two-stage mechanochemical synthesis of these products, depending on the parameters determining the process.

References

1. Butyagin Yu.P. Problems and prospects for the development of mechanochemistry // Russian Chemical Reviews. -1994. -V. 63. -No. 12. -P. 1031 - 1043. 2. Boldyrev V.V. Research in mechanochemistry of solid substances // Journal RFBR. 2004. No. 3 (37). P. 38 - 59. 3. Korchagin M.A., Grigorieva E.F., Barinova A.P., Lyakhov N.Z. Solid-phase regime of self-propagating high-temperature synthesis // Dokl. AN SSSR. - 2000. - V. 372. – No.1. - P. 40 - 42. 4. Bernard F., Gaffet E. Mechanical alloying in SHS research // Intern. J. Self-Propagating High-Temperature Synth. – 2001. V. 10. –No.2. – Pp. 109 – 132.

567 ______Non isothermal methods for materials synthesis

APPLICATION OF SHS AUXILIARY REACTION OF TITANIUM CARBIDE FOR INTRODUCTION OF AlN NANOPARTICLES INTO ALUMINUM MELT1 A.P. AMOSOV, Yu.V. TITOVA, D.A. MAIDAN, E. I. LATUKHIN Samara State Technical University, 244, Molodogvardeiskaya str., Samara, 443100, Russia, [email protected], +7(846)242-28-89

Due to a low weight, excellent mechanical properties, thermodynamic and dimensional stability at high temperatures, aluminum matrix composites reinforced with AlN nanoparticles are promising for use in aerospace, automotive and defense technology [1]. However, due to a high cost of AlN nanopowder, as well as a high cost and other disadvantages of existing solid-phase and liquid-phase methods of manufacturing Al-AlN nanocomposites, there is currently no industrial production of these nanocomposites [1]. In this regard, the study of the possibility of using the achievements of a simple energy-saving powder technology based on the process of self-propagating high-temperature synthesis (SHS) is of great interest for manufacturing Al-AlN nanocomposites [2]. Firstly, the cost of nitride nanopowders, obtained by SHS azide technology (SHS-Az), is about 2-3 times lower than the cost of similar nanopowders obtained by plasma chemical synthesis. Secondly, the SHS process creates a high temperature and thus contributes to wetting of ceramic nanoparticles and their insertion into the matrix. Thirdly, the synthesis of inexpensive reinforcing ceramic nanoparticles can be carried out directly in the matrix, ensuring their good adhesion to the matrix. The papers [2-4] present the results of our previous studies on the ex-situ fabrication of Al-AlN nanocomposites using different methods of introduction into the melt of aluminum (or its alloys) a nanopowder of SHS-Az brand of composition (AlN-35wt.%Na3AlF6), where a by-product Na3AlF6 (kryolite) played the role of flux. Direct mixing of AlN nanopowder in a bulk form in the aluminium melt did not lead to success due to the poor wettability of aluminium nanopowder with liquid Al and clumping the nanoparticles in the agglomerates. The use of pressed briquettes of nanopowdery master alloy of Cu- 4%(AlN-35%Nа3АlF6) composition allowed us to obtain a cast composite of the calculated composition of Al-1.2% Cu-0.035%AlN. Composite master alloy, obtained by melting the flux carnallite KCl·MgCl2 with nanopowder (AlN-35%Nа3АlF6), allowed us to introduce a maximum of 1%AlN into the matrix of alloy Al6%Mg. Nanocomposite with content up to 4%AlN was able to be obtained by mixing nanopowder (Al- 35%Nа3АlF6) in Al5%Cu alloy in the solid-liquid state (semi-solid process). In the present work, an attempt was made to increase the content of AlN reinforcing phase in aluminum matrix nanocomposite. The auxiliary reaction of SHS of titanium carbide Ti+C=TiC with adiabatic temperature of 3017oC was used for this purpose. Charge (Ti+C) with addition of different content of nanopowder (Al-35% Na3AlF6) was mixed, pressed into briquettes and injected into the melt of aluminum with a temperature of 900°C. It was determined whether the SHS reaction was initiated or not, how fully it proceeded, whether the inclusions of the unreacted charge remained, how evenly the reinforcing phases of AlN and TiC were distributed in the solidified aluminum matrix, what were the sizes and morphology of the particles AlN and TiC. As a result, it was possible to obtain a hybrid nanocomposite of the calculated composition of Al-7.7%AlN-19%TiC. The resulting nanocomposite sample had a fine-grained uniform dense structure, there were no shells, nonmetallic inclusions, pores and cracks, and its hardness was 64 HB. Thus, using a combination of ex-situ approach (introduction of pre-synthesized AlN nanopowder into the matrix melt) and in-situ approach (combustion synthesis of TiC particles in the matrix melt during composite fabrication), it was possible to increase the content of AlN nanoparticles to 7.7% and to obtain a cast hybrid aluminum matrix nanocomposite with two reinforcing phases (AlN and TiC). It should be noted that the hybrid reinforcement of aluminum alloys with mixtures of ceramic particles of different types has been successfully used and allows using the advantages of different particles [2, 5]. REFERENCES [1] Borgonovo C., Apelian D., Makhlouf M.M. // JOM. – 2011. – Vol. 63. – P. 57-64. [2] Amosov A.P., Titova Yu.V., Maidan D.A., Ermoshkin A.A. // Rus. J. Non-Ferr. Met. – 2015. – Vol. 56. – No. 2. – P. 222-228. [3] Titova Yu.V., Sholomova A.V., Kuzina A.A., Maidan D.A. // IOP Conf. Series: Mater. Sci. Eng. – 2016. – Vol. 156. - 012037. [4] Amosov A.P., Luts A.R., Titova Y.V. // Int. Conf. SHS-50. (Nov. 20–21, 2017, Chernogolovka, Russia): Proceedings. – P. 18-19. [5] Kumar N.M., Kumaran S.S., Kumaraswamidhas L.A. // J. Alloys Comp.  2015.  Vol. 650. - P. 318-327.

1 This work was executed at financial support of RFBR under the project No. 16-08-00826.

568 ______Non isothermal methods for materials synthesis EFFECT OF ALLOYING ON STRUCTURE AND PROPERTIES OF PARTICLE-REINFORCED ALUMINUM MATRIX COMPOSITES Al/TiC PRODUCED BY SHS IN ALUMINUM MELT1 A.P. AMOSOV, A.R. LUTS, E. I. LATUKHIN, A.D. RYBAKOV, V.A. NOVIKOV, S.I. SHIPILOV Samara State Technical University, 244, Molodogvardeiskaya str., Samara, 443100, Russia, [email protected], +7(846)242-28-89

Aluminum matrix composites (AMCs), discretely reinforced with ceramic particles, are the most widely used because they have isotropic properties and are produced by more simple and cheap technology compared with fibrous and layered AMCs [1, 2]. In recent years, much attention is paid to the use of titanium carbide (TiC) as a reinforcing phase, because the particles of TiC can give to AMCs a complex of properties, surpassing all other discretely reinforced AMCs [3]. This is because TiC possesses the FCC crystal lattice, coincident with the α-Al crystal lattice with the closest size, higher strength, hardness, thermodynamic stability. Both methods of powder metallurgy with initial matrix aluminum in the form of a powder and casting methods with initial matrix aluminum in the form of a melt are applicable for the fabrication of Al/TiC composites. A significant place among them is occupied by methods based on the use of the process of self-propagating high-temperature synthesis (SHS) which gives such distinctive features as ease of performance and high efficiency at low energy consumption. SHS methods belong to in-situ methods, when the reinforcing particles, synthesized in the matrix, have clean uncontaminated surface, which is important to ensure strong adhesion with the matrix, they are thermodynamically stable and do not enter into chemical reactions with the matrix, they can have a smaller size and more uniform distribution in the matrix [3]. More development was given to casting methods of in-situ producing AMCs with carrying out the combustion synthesis of reinforcing phase TiC from elemental Ti and C powders (and sometimes Al) in the aluminum melt, which are characterized by simple equipment, the possibility of producing castings of more complex shapes and large dimensions [3]. The improvement of casting SHS methods goes in two directions: (i) obtaining a nanoscale TiC reinforcing phase with the most uniform distribution of TiC particles in the aluminum matrix and (ii) alloying the aluminum matrix with various elements: Cu, Mg, Zn, Si, Sn, Mo [3-6]. The aim of this work was to study the influence of alloying elements of Cu and Mn on the structure and properties of promising composite Al/10%TiC (hereinafter wt. %) fabricated by SHS of reinforcing phase TiC in the aluminum melt. This study is a continuation of our studies on the possibility of obtaining a cast nanocomposite of Al-10%TiC based on the melt of pure aluminum [3]. The salt Na2TiF6 was added to the SHS charge (Ti+C) in amounts of 5-10% by weight. The charge portions of mass about 6-8 grams were wrapped in aluminum foil with a thickness of 50 – 100 µm and were introduced alternately in the melt of matrix alloy of Al-5%Cu or Al-5%Cu-2%Mn at 900°C. The following results were obtained. 1) Introduction into the Al melt of alloying additive of 5%Cu and addition of 10%Na2TiF6 salt to the SHS charge (Ti+C) allows obtaining nano - and ultrafine particles of TiC with a more uniform distribution over the body of Al-5%Cu matrix than in the case of unalloyed matrix. The structure of the cast composite (Al- 5%Cu)/10%TiC is characterized by low TiC particle agglomeration along the grain boundaries. 2) Sequential introduction into Al melt of alloying additives of 5%Cu and 2%Mn, and addition of 5%Na2TiF6 to the SHS charge leads to the formation of nano - and ultrafine particles of TiC which are uniformly distributed over the body of (Al-5%Cu-2%Mn)/10%TiC composite. 3) The alloying of aluminum matrix composites Al/10%TiC with Cu (5%) and Mn (2%) allowed us to achieve almost double strengthening (the ultimate tensile strength of 208 MPa) while maintaining a sufficiently high level of ductility (the elongation of 6%), that confirms the prospects of using alloyed AMCs of Al/TiC system as advanced engineering materials with improved mechanical properties. REFERENCES [1] Kainer K.U. // Metal Matrix Composites. - Verlag GmbH & Co. KGaA, Weinheim, Germany, 2006. [2] Rana R.S., Purohit R., Das S. // Int. J. of Sci. & Eng. Research. – 2012. – Vol. 3. – P. 1-16. [3] Amosov A.P., Luts A.R., Latukhin E.I., Ermoshkin A.A. // Rus. J. Non-Ferr. Met. – 2016. – Vol.57. – No. 2. – P. 106-112. [4] Shu S., Lu J., Qiu F., Xuan Q., Jiang Q. // Scripta Mater. – 2010. – Vol. 63. – P. 1209-1211. [5] Wu Q., Yang C., Xue F. // Mat. & Design. – 2011. – Vol. 32. – P. 4999-5003. [6] Li M., Zhai H., Huang Z., Liu X., Zhou Y., Li S., Li C. // J. Alloys Comp. – 2015. – Vol. 628. – P. 186-194.

1 This work was executed at financial support of RFBR under the project No. 17-48-630695.

569 ______Non isothermal methods for materials synthesis ULTRA-RAPID MICROWAVE SINTERING 1

K.I. RYBAKOV, YU. V. BYKOV, A.G. EREMEEV, S.V. EGOROV, V.V. KHOLOPTSEV, I.V. PLOTNIKOV, A.A. SOROKIN Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 Russia [email protected] +7 831 416 4831

We report the results of studies of microwave sintering of powder materials in the regimes with high heating rates and zero hold time at maximum temperature. Microwave processing of compacted samples based on Al2O3, ZrO2, Y2O3, MgAl2O4, and Yb:(LaO)2O3 ceramics was carried out using a gyrotron system operating at a frequency of 24 GHz with an output power of up to 6 kW [1]. The system is equipped with a fast computer control subsystem for automatic regulation of the microwave power and data acquisition. The heating regimes used in the experiments were of two types: 1) constant-rate heating at 50...200 °C/min, and 2) heating at a fixed microwave power level. In the latter case very high heating rates, up to thousands °C/min, were achieved via a controlled use of the overheating instability, also known as thermal runaway. The volumetric absorption of intense microwave radiation resulted in a very rapid densification with the duration of the high-temperature stage of sintering on the order of one to several minutes. In the rapid microwave heating regimes the effective high-frequency conductivity of the materials increased sharply at a certain threshold temperature. This suggests that the ultra-rapid sintering occurred via grain-boundary softening and formation of transient liquid phases. The indications of the presence of such phases can be observed in the microstructure images. The effect of ultra-rapid sintering is demonstrated to depend on the intensity of microwave radiation. The absorbed microwave power density required for the transition to the ultra-rapid sintering is on the order of 10...100 W/cm3 for a broad class of the materials [2, 3]. The obtained results suggest that ultra-rapid microwave sintering proceeds via essentially the same mechanism as the so-called flash sintering that occurs in the presence of ac / low-frequency dc electric field [4]. However, the implementation of the volumetric energy deposition by means of microwave processing is more advantageous from the technology scaleup viewpoint, since it does not require application of electrodes to supply electric current to the articles undergoing sintering [5]. The materials obtained by ultra-rapid microwave sintering possessed uniform structural and functional properties. The Yb:(LaO)2O3 laser ceramics samples were uniformly translucent, which suggests that they were sintered to full density with very low residual porosity [6]. The obtained MgAl2O4 samples exhibited good dielectric properties in the millimeter-wave and terahertz range [7]. Microwave sintering of metal powders can also be feasible provided that the metal particles have poor electric contact between them (e.g., due to the presence of native oxide layers on the particles). Although the overheating instability does not develop in metals because of the decreasing dependence of electric conductivity on temperature, ultra-rapid microwave sintering regimes are still possible via purposeful use of resonance effects [8].

REFERENCES [1] Bykov, Yu., et al. // IEEE Trans. on Plasma Science. – 2004. – V. 32. – P. 67-72. [2] Bykov, Yu.V., et al. // Materials. – 2016. – V. 9. – P. 684 (1–18). [3] Bykov, Yu.V., et al. // Technical Physics. – 2018. – V. 63, No. 3. – P. 391-397. [4] Raj, R. // J. Am. Ceram. Soc. – 2016. – V. 99. – P. 3226-3232. [5] Bykov, Yu.V., et al. // RU Patent 2592293, priority date March 02, 2015. [6] Bykov, Yu.V., et al. // J. Am. Ceram. Soc. – 2015. – V. 98. – P. 3518-3524. [7] Egorov, S.V., et al. //Radiophys. Quantum El. – 2017. – V. 59. – P. 690-697. [8] Rybakov, K.I., Buyanova, M.N. // Scripta Mater. – 2018. – V. 149. – P. 108-111.

1 This work was supported by Russian Science Foundation, grant # 17-19-01530.

570 ______Non isothermal methods for materials synthesis

MECHANICAL RESPONSE OF ZrB2 –BASED ULTRA-HIGH TEMPERATURE CERAMICS TO SHOCK PULSE LOADINGS IN A WIDE TEMPERATURE RANGE

SKRIPNYAK V.A., SKRIPNYAK E.G., SKRIPNYAK V.V., VAGANOVA I.K. National Research Tomsk State University, Russia [email protected], [email protected], [email protected], [email protected]

Mechanical response of ultra-high temperature ceramics (UHTC), located at elevated and high temperatures on intensive pulse loading is of interest in connection with the prediction of high-velocity impacts of compact bodies on protective ceramic constructions. UHTC based on ZrB2 have long term resistance to oxidation. ZrB2-B4C ceramic composites also have a melting point above 3500 K, good electrical conductivity. The modern technologies such as selective laser sintering and spark plasma sintering creation of structural elements made of UHTC occurs simultaneously with the production of ceramics. The choice of technological modes of sintering and pressing of powder systems is driven by the need to achieve required strength and functional properties. In this research mechanical properties of nanostructured ZrB2-B4C composites were predicted in a temperature range (297 -2200 K) and strain rates (10-3 to 106 1/s) by computer simulation. The multiscale approach was used for 3D computer simulation of deformation and failure of porous nanostructured ZrB2-B4C composites. It was shown strong influence of ZrB2-B4C nanocomposites microstructure on dynamic fracture at temperatures (295-473 K). The fracture of ZrB2-UHTC is caused by nucleation and coalescence of micro cracks. Cracks are formed near voids and in space between the strengthening particles at the mesoscale level. It was shown the transition of brittle to ductile fracture in ZrB2-B4C composites depends on strain rates. Thus, the strength threshold of nanostructured ZrB2-B4C composites depends on strain rates in temperature range (473-2200 K). The dynamic strength of ZrB2-B4C composites sharply decrease at temperature above 1773 K. It was shown that the dependence of normalized strength of ZrB2- B4C composites on the logarithm of normalized strain rates can be described by the power law.

571 ______Non isothermal methods for materials synthesis

SURFACE PROPERTIES ENHANCEMENT OF MAGNESIUM ALLOYS BY LOW ENERGY HIGH CURRENT PULSED ELECTRON BEAM

M. BESTETTI*, B. LAVANYA RANI*, S.A PASHIKANTI*, S. FRANZ*, A. VICENZO*, A. MARKOV** AND E. YAKOVLEV*** * Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Laboratorio di Ingegneria delle Superfici ed Elettrochimica Applicata “R. Piontelli” Via Mancinelli 7, 20131 Milano (Italia). **Tomsk Scientific Center SB RAS, 10/4, Akademicheskii pr., Tomsk, 634055, Russia ***Institute of High Current Electronocs SB RAS, 2/3, Akademicheskii pr., Tomsk, 634055, Russia

Mg-based light alloys have had increasing attention in the past few decades, due to their specific properties of low density and high strength/ductility ratio. Because of these properties Mg alloys are suitable to replace aluminium alloys and steels in some industrial components. The major problem to use Mg alloys are surface related issues, such as poor wear and corrosion resistance, that have strongly limited their potential for some specific applications. Therefore, surface treatment techniques are used to improve surface properties of the light alloys for global performance. The low-energy high-current pulsed electron beam (LEHCPEB) process is a relatively new surface modification technique. This technique is used to improve corrosion resistance by dissolution of intermetallic phases and forming a supersaturated solid solution and rapid solidification on surface of the Mg alloys. This technique improves surface properties and especially corrosion resistance. This work focuses largely on providing information on microstructure characterization, microhardness, XRD analysis and corrosion resistance of the LEHCPEB treated AZ91D and AM60B Mg alloys at different number of pulses and electron energies. Potentiodynamic polarization measurements showed that there is an improvement in corrosion resistance after the LEHCPEB treatments. The corrosion resistance is affected by the number of pulses and electron energy given by LEHCPEB.

Fig. 1. SEM cross section micrograph of AZ91 alloy after LEHCPEB with 16 pulses and 25 KeV electron energy.

572 ______Non isothermal methods for materials synthesis PRODUCTION OF THE MICRON POWDERS BY THE ELECTRIC EXPLOSION OF METALLIC FIBERS 1

A.S. SKRYABIN*, A.V. PAVLOV*, A.M. KARTOVA*, V.D. TELEKH*, M.M. SEROV**, A.E. SYTCHEV*** *Bauman Moscow State Technical University, Baumanskaya 2-ya, 5, Moscow,105005, Russia, [email protected], 8(499)2636085 **Moscow Aviation Institute, Volokolamskoe shosse, 4, Moscow, 125993, Russia ***ISMAN, Academician Osipyan str., 8, Chernogolovka, 142432, Russia

Nowadays the electric explosion [1] is under consideration as a prospective method for the production of micron metal powders. The explosion is executed by the “slow” energy input from a charged capacity С0 into a metal fiber (with a resistance of R0) produced by the method [2]. That condition can be expressed [3] as

ττd MHD , (1) where τd RC00is the time constant of the circuit and τMHD  0.2...1.4 μs is the characteristic time of the magnetohydrodynamic MHD instabilities. Experimental studies were performed in a chamber in an inert argon atmosphere (with pressure of ≈1 atm). The circuit included a С0 =0.6 μF capacitor, a charger and a high performance thyratron (Pulsethech Ltd) with an igniter. A titanium fiber (with an average diameter of 20…50 μm) was as the resistance R0 and the raw material. The charger allowed to the capacitor charging up to a voltage U0 from 2.5 to 5.0 kV. The current and voltage dynamics were measured by a Rogovsky belt and a voltage divider. The explosion products collected inside a quartz tube were characterized by SEM, EDX and optical microscopy. The measuring of the current and voltage dynamics indicated that the characteristic current amplitudes

Imax were about ≈40…70 A. The typical τd were about ≈40…100 μs. So the condition (1) was fulfilled at the studies. The produced titanium particles (see Fig. 1) had a spherical shape with an average diameter from 80 to 170 μm. A purity of the particles was varied from 97.32 to 99.63 % as for the raw fibers. Oxygen was not detected.

Fig. 1. The typical produced Ti particle

The “slow” (with τd  40...100 μs) electric explosion in an inert atmosphere is perspective for the production of metallic particles from the fibers. The energy consumption is about 0.5…1.0 kW∙hour per 1 kg of Ti particles. The using of the micron titanium particles are under consideration for different applications, such as a catalyst, a raw for additive manufacturing etc.

REFERENCES [1] Surkaev A.M. // Technical Physics Letters.  2014.  40.  № 2. 23-29. [2] Mitin B.S., Serov M.M., Yakovlev V.B., Edneral N.V. //The physics of metals and metallography.  1999. – 87. № 3. 221-225. [3] Surkaev A.M // Technical Physics. – 2015. – 85. - № 7. 37-44.

1 This work was performed using research facilities cluster “Beam-M” (BMSTU).

573 ______Non isothermal methods for materials synthesis SYNTHESIS OF MIL COMPOSITES BY VARIOUS METHODS1

S.A. ZELEPUGIN*,**, O.A. SHKODA*, O.K. LEPAKOVA*, A.S. ZELEPUGIN*,**, N.G. KASATSKY* *Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Avenue, Tomsk, 634055, Russia, [email protected], +7(3822)492294 **National Research Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia, [email protected], +7(3822)492294

Progress in the creation of new technological innovations mainly depends on the development and improvement of technologies for obtaining materials with required properties, so the creation of materials with desired structural and functional properties is currently an area of increased attention in materials science and technology. The new promising class of structural materials includes metal-intermetallic laminate composite materials (MILCM) which are represented by a multilayer composition with alternating

metal and intermetallic layers [1, 2]. These composite materials are attractive for use in aerospace engineering and many other areas, and methods for obtaining of MILCM allow us to use new technologies expanding the functionality of laminate composites and the area of application. This work considers four methods such as thermal explosion, reaction sintering, reaction compression, and explosive welding + sintering for the obtaining of Ti-TiAl3 metal-intermetallic laminate composite materials. A powder mixture of titanium and aluminum with a stoichiometric composition (37.2 wt% Ti + 62.8 wt% Al) was used to synthesize titanium tri-aluminide (TiAl3). To conduct the synthesis, a setup was specially designed. A tungsten-rhenium 200 micron thermocouple placed in the powder layer of the sample was applied to determine temperature. Ti and Al plates and a PM-12M muffle furnace were used for reaction sintering. The reaction compression (reaction sintering together with constant pressure) was conducted using a special setup at Institute of Metal Physics UB RAS (Yekaterinburg). In the work the Ti and Al plates were used, and temperature, pressure, and the process time were varied. Explosive welding was conducted in an explosive chamber (Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk). The samples obtained by explosive welding were subjected to a reaction sintering in a muffle furnace at the temperatures of 700 and 900°C for 2, 4, 6 and 8 hours. The microstructure and phase composition of the samples were studied by the X-ray diffraction, local X-ray spectrum and optical microscopy methods. The study showed that the multilayered composite could be obtained by all four methods. However it should be noted that there are disadvantages in each of these methods. After synthesis in the thermal

explosion mode, high porosity and low strength are observed in the intermetallic layers of the samples. There are also problems concerning mechanical and physico-chemical compatibility of different materials at the boundary between layers, which leads to the absence of a strong bond between the titanium foil and synthesized intermetallide. High porosity and low strength were observed in the intermetallic layer after reaction sintering, and increased porosity was formed in the middle of the intermetallic layer. A central layer of increased porosity was also formed after explosive welding and sintering, which reduces strength characteristics of the composite. The method of reaction compression partially solves the problem of high porosity in the intermetallic layer, but nevertheless, there are pores nonuniformly located in the layer, which requires an additional improvement of modes for the synthesis of metal-intermetallic laminate composite materials. REFERENCES [1] Cao Y., Zhu S., Guo C., Vecchio K.S., Jiang F. // Applied Composite Materials. - 2015. - Vol. 22. - P. 437–456. [2] Zelepugin S.A., Mali V.I., Zelepugin A.S., Ilina E.V. // Shock Compression of Condensed Matter. USA: American Institute of Physics. - 2012. - Vol. 1426. - P. 1101-1104.

1 The work was carried out within the state task of FASO Russia (No. 0365-2018-0003) and partially supported by RFBR (project No. 16-08-00037).

574 ______Non isothermal methods for materials synthesis A MULTICOMPONENT MEDIUM MODEL FOR POROUS MIXTURES UNDER EXPLOSIVE LOADING

O.V. IVANOVA, S.A. ZELEPUGIN Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294

Synthesis of new materials under equilibrium conditions is completely studied. Prospects are connected with producing metastable compounds in nonequilibrium conditions by means of explosive loading. High pressures and speeds of a substance causing an initiation of chemical reactions create extreme conditions for production of new materials. In addition, shock waves cause mechanochemical activation of a mixture, high rate of fragmentation, and mixing of particles, which creates favorable conditions for initiation and proceeding superfast chemical reactions [1]. Consequences of explosive loading of substances are sure to be too diverse and complicated to be predictable. However, systematic fundamental investigations in physics and chemistry of shock waves with the use of specific systems open vast possibilities to manage the processes of structural chemical and phase transformations and allow improving essential properties of materials and even producing new materials with unique properties. The aim of this work is to develop a model of a multicomponent medium for numerical prediction of porous reacting mixture behavior under explosive loading. The system of equations governing the nonstationary adiabatic motion of every component in a space- fixed volume of a compressible solid mixture with allowance for the exchange of momentum, energy, and mass between components as well as the evolution of microdamage and chemical transformations comprises the continuity equation, the equation of motion, and the energy equation. An equality of components pressure is chosen as a condition for joint deformation of components. To solve the explosive loading problems of porous mixtures, the finite element method is used. On the basis of this method every component of a mixture simultaneously occupies the same volume as the mixture and consists of a set of the final elements connected with the node points. Inside every element, components interact with each other, exchanging momentum, energy, and mass (in the presence of chemical reactions) within the framework of the multicomponent medium model. After interaction of components and their summary contribution to node forces of an element, the components in a mixture obtain the velocity of the corresponding element. We consider the axisymmetric problem of explosive loading of multicomponent mixtures (Al-S and Al- S-C) placed into a cylindrical steel ampoule. The porosity of the mixture was 0.4 (ratio between the volume of pores and total volume). The height of the cylindrical sample was 64 mm, the diameter was 14 mm. The thickness of the lateral wall of the ampoule was 3 mm, the thickness of top and bottom lids was 10 mm. The height of the ampoule was 84 mm, the external diameter was 20 mm. In the computations the actions of the detonation products surrounding the ampoule was simulated by the action of pressure on the upper part of the ampoule in a vertical (axial) direction and on the lateral surface of the ampoule in a horizontal (radial) direction. In the axial direction the action started at the initial moment of the process, and in the radial direction the action stated during propagation of the detonation wave from top to bottom [2]. The detonation velocity was D = 2.8 km/s on the basis of experimental data. The P0 = 3.2 GPa value was chosen on the basis of numerical and experimental evaluations. The results of computations have shown that there are optimal parameters of explosive loading that provide the obtaining of materials with desired properties. For an example, the thickness of the explosive layer essentially influences on the positive results of explosive loading. Insufficient thickness of explosives, as well as the excessive thickness may be a reason for an incompletely compacted final product or lead to the formation of cracks or damage. Explosive synthesis was also found to depend on dispersity and duration of explosive loading. A decrease in the particle size of reagents simplifies and accelerates reactions. REFERENCES 1] D.E. Eakins, N.N. Thadhani. Shock compression of reactive powder mixtures, Int. Mater. Rev.- 2009. -V.54 (4).-P. 181–213. 2] S.A. Zelepugin, O.V. Ivanova, A.S. Yunoshev, V.V. Sil’vestrov. The development of the aluminum sulfide synthesis reaction on explosive loading of a cylindrical ampoule, Doklady Physical Chemistry.-2010.-V. 434(2).-P.172–176.

575 ______Non isothermal methods for materials synthesis

MACROKINETICS OF STRUCTURAL AND CHEMICAL TRANSFORMATIONS IN A BINARY POWDER MIXTURE AFTER MECHANICAL TREATMENT

O O . V . LAPSHIN

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], +7 (3822)492294

One of the effective methods for accelerating chemical transformations in powder mixtures is intense mechanical treatment [1 - 4]. Planetary mills are most often used for this purpose in practice. After mechanical treatment, along with the grinding of powders, there is the formation of an interphase surface to initiate chemical interactions. The interphase surface is formed by «spreading» one of the reagents on the other in the place of frictional contact. During mechanical treatment, there is the continuous grinding of such layered structures (microcomposites) and the formation of new composites with a more complex internal structure, in which reaction products can appear. The development of this process reduces the size of separate layers of reacting substances, namely the scale of heterogeneity that determines the characteristic time of mass transfer of reactants towards each other [5]. Simultaneously with the grinding and formation of microcomposites, additional structural defects are created in the components of the mixture, where excess energy is accumulated, in contrast to the untreated material. In the macroscopic approximation, the some proportion of this energy reduces the activation barrier of chemical interaction. Depending on the intensity and time of mechanical treatment, chemical transformations can occur in the mill. The purpose of this paper is to construct a mathematical model in the macroscopic approximation for the mechanical treatment of a binary mixture considering the formation of mechanocomposites to estimate the kinetics of chemical transformations. The dynamics of the mechanical treatment of the powder mixture is described by the equations as follows: grinding, change in the relative volumes of components during agglomeration, change in the interphase surface in mechanocomposites, chemical transformations, the rate of excess energy in the reagents and the reaction product. The dynamics of chemical and structural transformations in mechanocomposites is numerically studied during mechanical treatment. The results have shown that even after the grinding limit is reached and the size of the particles and the external surface area are practically not changed, the internal structure becomes more complicated, and the magnitude of the interphase surface and the uniform distribution of the components in the mechanocomposites are increased. This structure evolution of the mechanically processed powder mixture is in qualitative agreement with the experimental data given in [6, 7] and with the papers cited in these works. Depending on the control parameters, the application areas of different modes are determined for the mechanical treatment of the powder mixture. Analytic relations are obtained for estimating the parameters of the layered structure of mechanocomposites, the degree of activation and the fraction of the converted substance. References 1. Butyagin Yu.P. Problems and prospects for the development of mechanochemistry // Russian Chemical Reviews. 1994. V. 63. No. 12. P. 1031 - 1043. 2. Boldyrev V.V. Research in mechanochemistry of solid substances // Journal RFBR. 2004. No. 3 (37). P. 38 - 59. 3. Grigoryeva T.F., Barinova A.P., Lyakhov N.Z. Mechanochemical synthesis in metallic systems. Novosibirsk: Parallel, 2008. 311 p. 4. Khina B.B., Formanek B. On the Physicochemical Mechanism of the Influence of Preliminary Mechanical Activation on Self- Propagating High-Temperature Synthesis// Solid State Phenomena. 2008. Vol. 138. pp. 159-164. 5. Mechanocomposites are precursors for creating materials with new properties. Ed. by O.I. Lomovsky. Novosibirsk: SB RAS, 2010. 424 p. 6. Smolyakov V.K., Lapshin O.V. Macroscopic kinetics of mechanochemical synthesis. Tomsk: IAO SB RAS, 2011.192 pp. 7. Lyakhov N.Z., Talako T.L., Grigorieva T.F. Influence of mechanoactivation on the phase and structure formation during SHS. Novosibirsk: Parallel, 2008. 167 p.

576 ______Non isothermal methods for materials synthesis KINETICS OF REACTION TRABSFOMATIONS IN COMBUSTION WAVE FOR THE TITANIUM - MOLYBDEN – NITROGEN SYSTEM.

V.G. SALAMATOV, О.А. SHKODA

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], +7(3822)492294 [email protected]

Combustion synthesis (CS), also known as self-propagating high-temperature synthesis, is currently considered to be one of the efficient industrial methods for the production of different advanced materials including nanomaterials, alloys, refractory inorganic compounds and functional materials. In this work, the peculiarities of filtration combustion are studied using Ti-Mo reaction systems. In addition, characteristics of the thermal wave structure are investigated during nonstationary combustion, and the mechanism of the structure formation of product is found. The titanium-molybdenum-nitrogen system was selected due to the fact that the synthesis products of the system could be used as hardening coatings for equipment operating under extreme conditions. In addition, the results obtained are important for deep understanding the mechanisms of filtration combustion of metals. The experiments were conducted using the developed technique of dynamic pyrometry [1] and high-speed video recording. According to the results obtained, the combustion of the mixture in nitrogen is conducted in the surface mode. This mode is characterized by the propagation of a reaction wave in a narrow near-surface layer of the sample followed by the penetration of combustion from the surface to the center, as can be seen from the increase in the glow intensity of the hole after the passage of a surface wave. The peculiarities of combustion observed are the presence of local reaction sources and the complex three-dimensional structure of the temperature field in the reaction wave. The measurements have shown that the maximum temperature of the surface wave outside the combustion source (T1) is 200 K lower than the temperature that is reached at the center of the sample (T2). This is explained by the effect of heat accumulation during nitrogen filtration in the central part of the sample. This fact corresponds to the observed fusion in the central part of the sample, where the temperature is 110 K higher than the melting point of titanium. The temperature of the surface combustion wave inside the combustion source exceeds the temperatures T1 and T2, which is explained by the known effects of heat accumulation in local combustion sources under the conditions of the thermal and chemical instability of nitriding reactions [3]. The time difference (Δt) for reaching the maximum temperature on the surface and inside the sample allows the linear propagation velocity to be estimated (0.9 mm/s). The results demonstrated that all values of the maximum combustion temperatures are located within the «L-S» region as compared to the «Ti-Mo» state diagram [4,5]. The values obtained for the conversion degree of combustion products with variation of all experimental parameters are also located within the «L- S» region. When all the experimental points were plotted on the graph, for the case when the ratio of absorbed nitrogen to molybdenum was constant, it was found that, despite the variation of all experimental parameters, all the experimental points were located on 11 curves corresponding to 11 types of molybdenum nitrides. The ratio of molybdenum to titanium is always the ratio of integers (MonNm), i.e. the ratio of n to m corresponds to a number of stoichiometric formulas of molybdenum nitrides: from Mo5N3 to MoN3.

References 1. Salamatov V.G., Tsyba G.A., Kirdyashkin A.I., Maksimov Yu.M. A television system for determining dynamic temperature fields during SHS processes // Measuring techniques. 2002, No. 9. Pp. 41-45). 2. B. Sh. Braverman, V. G. Salamatov, M. Kh. Ziatdinov, Yu. M. Maximov. The effect of sample size on the Transition to surface combustion, VII International Symposium on Self – Propagation High – Temperature Synthesis: book of abstracts, Cracow, Poland, 2003, Р. 13. 3. Ivleva T.P., Merzhanov A.G., Shkadinsky K.G. Mathematical model of spin combustion, Dokl. AN SSSR.- 1978.-V. 239.- No. 6. - P.1086-1088. 4. V.G. Salamatov, L.G. Raskolenko. Link between the combustion parameters of titanium-molybdenum mixtures in gaseous nitrogen and a phase diagram of metals. Proceedings of the VI All-Russian Scientific and Technical Conference: Mechanics of Aircrafts and Modern Materials, Tomsk.-1999.-P.68-70. 5. Salamatov V.G. Combustion of titanium-molybdenum mixtures in nitrogen. Proceedings: Self-propagating high-temperature synthesis: Materials and technologies / ed. by Prof. Evstigneeva V.V., Novosibirsk: Nauka.-2001.-P.94-99.

577 ______Non isothermal methods for materials synthesis

OBTAINING OF VANADIUM NITRIDES DURING THE COMBUSTION OF VANADIUM OXIDE 1 WITH CALCIUM AND CALCIUM NITRIDE IN NITROGEN

B.Sh. BRAVERMAN, А.N. AVRAMCHIK, YU.М. MAKSIMOV, A.M. SHULPEKOV

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294

Calciothermic reduction of metal oxides is accompanied by the high amount of heat release, which leads to the significant heating of a green mixture. A relatively low melting temperature of calcium (838 °C) results in the formation of liquid with a high chemical activity, and therefore, the choice of the reactor material becomes a serious problem. The known method for the hydride-calcium obtaining of metal powders [1] reduces the temperature of reduction reaction to a relatively low temperature (1200 °C) due to adding pure metal powders to a green mixture. Such temperatures do not allow synthesis to be conducted in the self-propagating mode. There is a need

in the heating of reaction masses, which leads to high energy costs. Partial replacement of calcium by calcium nitride, with the appropriate amount of nitride, allows the reduction reaction to be conducted in the self-propagating mode without external supply of heat and the formation of a large amount of flowing reaction masses at temperatures up to 2500 оС. During synthesis in the combustion mode, the reaction time decreases from several hours to several minutes.

Vanadium nitride was obtained from vanadium oxide during the combustion of V2O5, Ca, Ca3N2 mixtures under the nitrogen atmosphere. The calculated values of the adiabatic reaction temperature are shown in Fig. 1.

Fig. 1. Adiabatic combustion temperature for the stoichiometric composition «V2O5 - Ca - Ca3N2 – nitrogen» versus the amount of Ca3N2 replacing metallic calcium. Nitrogen pressure: (1) - 1; (2 )- 3, (3) - 6 MPa

Powder mixtures were burned in paper cylindrical cups with a diameter of 23 mm in a constant-volume bomb. The preservation of the sample shape was observed when more than 70% of metallic Ca was replaced

by Ca3N2 nitride obtained by the combustion of Ca powder in nitrogen [2]. The measured combustion temperatures were lower than the calculated ones, which can be explained by the heat removal to the environment. After acid removal of calcium compounds, the main phases in the products are vanadium nitrides. REFERENCES [1] Kasimtsev A.V., Levinsky Yu.V. Hydride-calcium powders of metals, intermetallides, refractory compounds and composite materials. M.: MITHT, 2012. [2] Avramchik A.N., Chukhlomina L.N., Maksimov Yu.M., Bulgar K.A. Bulletin of Tomsk Polytechnic University.- 2013.- V.322. - No.3.- P.26-28.

1 This work was supported by RFBR (No. 18-03-00875)

578 ______Non isothermal methods for materials synthesis APPLICATION OF SHS PROCESS FOR FABRICATION OF

1 COPPER-TITANIUM SILICON CARBIDE COMPOSITE (Cu-Ti3SiC2)

A.P. AMOSOV, E.I. LATUKHIN, A.M. RYABOV, E.R. UMEROV, V.A. NOVIKOV Samara State Technical University, 244, Molodogvardeiskaya str., Samara, 443100, Russia, [email protected], +7(846)242-28-89

Metal matrix composite of copper - titanium silicon carbide (Cu-Ti3SiC2) attracts the attention of researchers as a promising electrical material with a low coefficient of friction, good electrical conductivity and thermal conductivity, high erosion resistance, which is important for the use in sliding electrical contacts and electrodes for electrical discharge machining of materials [1, 2]. Such properties of the composite are largely due to the structure and properties of titanium silicon carbide (Ti3SiC2), belonging to a new class of ternary compounds with a layered structure – the so-called MAX phases, which occupy, in their properties, an intermediate position between ceramic and metal materials [3]. Cu-Ti3SiC2 composite is produced by two- stage technologies: at the first stage, Ti3SiC2 is synthesized from a mixture of Ti, Si and C powders (most often by reaction sintering), and then at the second stage, the composite is produced from a mixture of Cu and Ti3SiC2 powders by powder metallurgy methods: vacuum sintering, infiltration or spark plasma sintering. Obviously, such technologies are long-term, energy-consuming, require complex and expensive equipment, so the study of the possibility of using a simple, energy-saving powder technology based on the process of self-propagating high-temperature synthesis (SHS) for the single-stage production of Cu-Ti3SiC2 composite from relatively inexpensive powders of its constituent elements is of great interest. Results of our previous investigations on application of SHS process for fabrication of a porous skeleton of Ti3SiC2 and composites on its basis with simultaneous infiltration by melts Ni, Ti or Fe are presented in works [4, 5]. This paper presents the results of a similar study to fabricate Cu-Ti3SiC2 composite. To synthesize Ti3SiC2, a SHS charge was used, which was an initial mixture of powders of titanium, silicon and carbon (soot) with a ratio of components 3Ti+1,25 Si+2C. From this powder mixture, the charge briquettes in the form of a cylinder with a diameter of 40 mm and a mass of 20 g were formed by unilateral compaction. The porosity of the charge briquettes was about 0.5. Powder briquettes of copper weighing 20, 25, 30 and 35 g were compacted separately in a mold of 40 mm diameter. The SHS process was carried out in the assembly of three contiguous briquettes (the copper briquette between two charge briquettes) in the air atmosphere. For a more intimate contact of the briquettes and prevention of warping the reaction products during the synthesis process, the upper briquette was forced to the others by a weight of 500 g. Due to the heat of the SHS reaction, initiated simultaneously in the charge briquettes and resulted in formation of porous skeleton of Ti3SiC2 in these briquettes, the copper in the middle briquette was heated, melted and impregnated porous reaction products of the upper and lower briquettes. Using X-ray diffraction, scanning electron microscopy and energy dispersive analysis, it was established that the melt of copper reduces the amount of MAX phase of Ti3SiC2, partially destroying it and leading to the formation of phases of titanium carbide, titanium silicide, silicon carbide and copper silicide. The study of distribution of copper over sample body showed that copper is distributed unevenly, the maximum amount of copper is contained in the central part of the composite sample. The deintercalation of silicon from Ti3SiC2 and dissolution of the silicon in molten copper can be considered as the main reason for the destruction of Ti3SiC2. The addition of 10% silicon to the composition of initial copper briquette and, accordingly, the presence of 10% silicon in the copper melt led to an increase in the height of the peaks of the MAX phase and a decrease in the height of the peaks of titanium carbide and pure copper on the diffractogram of the composite, but reduced the uniformity of copper distribution in the composite sample body. REFERENCES [1] Ngai T.L., Zheng W., Li Y. // Prog. Natur. Sci.: Mater. Int. - 2013. - Vol. 23. – No. 1. - P. 70-76. [2] Oglezneva S.A., Kachenyuk M.N., Ogleznev N.D. // Rus. J. Non-Ferr. Met. - 2017. – Vol. 58. - No. 6. - P. 649–655. [3] Barsoum W. // Prog. Solid State Chem. - 2000. - Vol. 28. - P. 201—281. [4] Amosov A.P., Latukhin E.I., Davydov D.M. // Modern Applied Science. – 2015. – Vol. 9. – No. 3. – P. 17-24. [5] Latukhin E.I., Amosov A.P., Ryabov A.M., Illarionov A.Y., Novikov V.A. // SHS 2017. XIV Int. Symp. on SHS (September 25- 28, 2017, Tbilisi, Georgia): Book of Abstracts. P. 32-34.

1 This work was executed at financial support of RFBR under the project No. 16-08-00867.

579 ______Non isothermal methods for materials synthesis MECHANOACTIVATION AND BURNING OF ALUMINUM AND COPPER OXIDE MIXTURES1

A. DOLGOBORODOV *, A. STRELETSKII **, V. KIRILENKO **, B. YANKOVSKII **, S. ANAN'EV **, I. KOLBANEV *, G. VOROB'EVA * *Join Institute for High Temperature RAS, Izhorskaya St. 13 Bd.2, Moscow, 125412, Russia, [email protected], +74954832295 **Semenov Institute of Chemical Physics RAS, Kosygin St. 4, 119991, Moscow, Russia

The method of preliminary mechanoactivation (MA) of mixtures of solid oxidizer and metal powders has been actively used since the beginning of the 2000s [2-5]. During MA, the components are shredded and mixed at the submicron and nano levels, and new defects in the crystal structure are formed, which makes it possible to increase the rate of chemical reaction on the surface of the reagents. As result we obtain Mechanically Activated Energetic Composites (MAEC) with increased sensitivity to thermal affect and high burning rate. In this paper new research results on the initiation and burning of MAEC Al/CuO based on micron and nanosized powders using MA are presented. As the initial components, micron and nanosized powders were used: industrial pyrotechnic powder Al PP-2L (flake 50 ÷ 100 μm × 2 ÷ 5 μm), CuO 20÷50 μm, nanosized nAl (Alex 100 ÷ 200 nm) and nCuO (50 ÷ 80 nm). Al weight content was from 18 to 25%. In some cases, additives of various metals with catalytic effect (Hf, Ni) were also used. Mixing and activation was carried out in the vibration ball mill of the Aronov design (energy intensity J = 3.7 W/g) or in the planetary mill "Activator-2sl» (J = 9.7 W/g) with steel drums and balls. Liquid hexane was added to reduce friction heating and to prevent the reaction. The starting powders and MAEC were analyzed by X-ray diffraction, electron microscopy and thermo-gravimetric analysis. A number of the dependences of the combustion parameters on the activation dose Da were determined in experiments: ignition temperature by hot surface, brightness temperature of burning products, burning rate in cylindrical channels and electrical resistivity in cloud of products. The dynamics of the expansion of products in free space during electric spark and shock wave initiation was analyzed. To measure the ignition temperature Ti, the test powder weighing 30 ± 1 mg was placed in a container, introduced into the furnace and discharged onto the heated surface. The ignition delay was determined by a stopwatch with an accuracy of 1 sec. Depending on Da, Ti varies from 170 ºC to 400 ºC. The burning rate was measured in plastic and glass tubes (diameter 4-10 mm) by recording of products emission by light fiber or high speed photography. The porosity of charges was 60-70%. The initiation was carried out by heating the NiCr wire or by an electric spark. The spark energy was regulated by changing the current amplitude in the range of 1.5-50.0 mJ at duration of the current pulse 1.2 μs. Depending on Da and the initiation method, the measured burning rate varies from 10 m/s to 700 m/s, and the product temperature is from 2000 K to 3700 K. In case of low-energy electric spark (<20.0 mJ), combustion has a pronounced heterogeneous character. The highest reactivity, burning rate and temperature of products for MAEC Al/CuO were obtained at Da = 1.8÷2 kJ/g. With increasing Da there is a partial reaction of the reagents at the time of activation. In the case of shock-wave initiation of compositions in a semi-enclosed volume, the main process of energy release proceeds in the flow of products dispersed in the unloading wave. The initial flow rate of the products is more than 800 m/s. The maximum brightness temperature in the cloud of partially ionized products reaches 3700 K, the resistivity is about 107 Ω * mm2/m. The results of the work have shown the promise of preliminary mechanochemical activation for the production of fast-burning thermite compositions of Al/CuO. The use of the original nanoscale components is inadvisable, since it does not give appreciable advantages. Also it was shown, that small addition of Hf can increase the reaction ability CuO based mixtures.

REFERENCES [1] A.Yu. Dolgoborodov, M.N. Makhov, I.V. Kolbanev, A.N. Streletskii // RF Patent No. 2235085. − 2004. [2] A.Yu. Dolgoborodov // Combustion, Explosion, and Shock Waves. − 2015. − 51(1). − 86–99.

1 This work was supported by of the state program of basic research of Russia (JIHT RAS - A. Dolgoborodov, B. Yankovskii and S. Anan'ev - project 0044-2014-0016, registration code АААА-А-16-116051810082-7, and ICP RAS - A. Streletskii, V. Kirilenko, I. Kolbanev, G. Vorob'eva, - project 0082-2018-002, registration code АААА-А18-118031490034-6)

580 ______Non isothermal methods for materials synthesis PHASE COMPOSITION, STRUCTURAL PARAMETERS AND MAGNETIC PROPERTIES OF BARIUM HEXAFERRITE, SYNTHESIZED BY SOL-GEL COMBUSTION USING DIFFERENT ORGANIC FUEL

R. V. MININ*, V. I. ITIN*, V. A. ZHURAVLEV**, YU. M. LOPUSHNYAK**, V. A. SVETLICHNYI**, I. N. LAPIN**, D. A. VELIKANOV***, I. YU. LILENKO**

* Tomsk Scientific Center, SB RAS, Akademichesky ave 10, bld. 3, Tomsk, 634021, Russia, Email: [email protected], phone: +79234061935 ** Tomsk State University, Lenin ave 36, Tomsk, 634050, Russia ***Kirensky Institute of Physics, Federal Research Center KSC SB RAS, st. Akademgorodok 50, bld. 38, Krasnoyarsk, 660036, Russia

Hexagonal ferrites, in particular Barium hexaferrite BaFe12O19 with the crystallographic structure of M- type, are broadly used to manufacture permanent magnets as well as various components for radar absorption material and microwave devices. A vivid scientific and practical interest to this material is caused by the fact that it possesses high values of the Curie temperature (TC), coercive force (HC), specific saturation magnetization (σS) and magnetocrystalline anisotropy field (Ha1). In addition, its magnetic properties are stable in a wide range of temperatures. The synthesis of BaFe12O19 hexaferrite powders was carried in a sol-gel combustion mode. The aqueous solutions of Barium nitrate and Iron nitrate were used as reagents. The aqueous solutions of carbamide (sample 1), sucrose (sample 2), glycin (sample 3) and citric acid (sample 4) were used as an organic fuels.

20 30 18 16 25 14 20 12 10 15 8

Volume (%) 6 Volume (%) 10 4 5 2 0 0 15 45 75 105 135 165 195 225 15 45 75 105 135 165 195 225 a) Particle size (nm) b) Particle size (nm)

25 35

30 20 25 15 20 10 15

Volume (%)

Volume (%) 10 5 5 0 0 15 45 75 105 135 165 195 225 15 45 75 105 135 165 195 225 c) Particle size (nm) d) Particle size (nm)

Fig 1. SEM pictures of products after sol-gel combustion and heat Fig 2. Bar charts with particle size distribution of products treatment. a) – sample No 1, b) – sample No 2, c) – sample No after sol-gel combustion and heat treatment. a) – sample No 3, d) – sample No 4. 1, b) – sample No 2, c) – sample No 3, d) – sample No 4.

The sample synthesized with carbamide as an organic fuel has the least target phase ВаFe12O19 output ~ 77 %. Other samples contain more than 92% of Ba-M phase. The granulometric analysis revealed that the samples obtained with the use of carbamide (No 1) and glycin (No 3) demonstrates a wide particle size distribution and the average particles size are 120 ÷ 135 nm. Whereas the samples synthesized with the use of sucrose (No 2) and citric acid (No 4) demonstrate narrower particle size distribution as well as the smaller particle size: the sample No 2 –75 ÷ 90 nm, the sample No 4 – 90 ÷ 105 nm. The samples No 2 and No 4 with the narrow particle size distribution have the biggest value of magnetization. At room temperature it is 56.6 and 59.0 emu/g respectively. The values obtained are similar to ones given in. The paraprocess affects the magnetization processes significantly. Average paraprocess -3 3 .susceptibility for all samples is χpara. ≈ 0.125۰10 cm /g The values of the magnetomechanical ratios estimated from the FMR experiments in the limits of the experimental error are the same as for the spin moment of a free electron.

581 ______Non isothermal methods for materials synthesis SYNTHESIS OF CUBIC FERRITE COFE2O4 BY SPRAY PYROLYSIS

R. V. MININ* * Tomsk Scientific Center, SB RAS, Akademichesky ave 10, bld. 3, Tomsk, 634021, Russia, Email: [email protected], phone: +79234061935

The purpose of this paper is to assess the prospects of using the method of spray pyrolysis for the synthesis of nanoscale powders of cubic and hexagonal ferrites for use in medicine and technology. For the synthesis of cobalt ferrospinel used reaction:

Co(NO3)2·6H2O + 2Fe(NO3)3·9H2O + C6H8O7 + O2 = CoFe2O4 + 6CO2+ 28H2O + 5NO2 + 3NO

Aqueous solutions of cobalt nitric acid 6-aqueous, iron nitric acid 9-aqueous and citric acid with a concentration of 1M were used as reagents. After that they were mixed in accordance with the relationship:

{[ ( ) ] [ ( ) ]} { }

The concentrated ammonium hydroxide solution was added to the obtained solutions by drops with constant stirring on a magnetic stirrer until the pH = 2 value was reached, which was measured using a portable digital pH meter. The initial solution using an ultrasonic nebulizer was transferred to the aerosol state, which was supplied through flexible tubes to the working zone of a tube furnace heated to a temperature of 1200 º C, after which the synthesis product was washed in a Drexel flask. Then, with the help of a permanent magnet, solid particles were deposited at the bottom of the container and dried. The industrial aspirator was used to regulate the aerosol flow rate through the working area of the furnace. After spraying, the solution drops are heat treated, a tubular furnace is passed, whereby the solvent evaporates and a solid phase of the dissolved substance appears, which is then dried. Further heat treatment leads to the formation of porous particles, which are compacted during sintering.

35000

30000 

25000

20000  - CoFe2O4

15000  I, arb. I,un. arb.  10000  

 5000        0 0 20 40 60 80 100 120 2Thetta, deg

Fig 3. Synthesis product x-ray Fig 2. Microstructure of product

Thus, the use of the spray pyrolysis method for the synthesis of ferrite powders for medical and radio engineering purposes is of great scientific interest. Further research will be aimed at assessing the applicability of this method to obtain ferrites of other stoichiometric compositions (including hexagonal), the development of a synthesis methodology to obtain smaller particles, as well as to study the basic magnetic properties of synthesized powders.

582 ______Non isothermal methods for materials synthesis

583 ______Non isothermal methods for materials synthesis APPLICATION OF SELECTIVE LASER ALLOYING IN ORTHOPEDICS AND TRAUMATOLOGY OF VETERINARY1

A.YA. LEYVI*, R.M. BAYTIMIROV*, P.A. LYKOV*, I.A. VOLODIN**, A.V. SHUDRIK *Federal State Autonomous Educational Institution of Higher Education “South Ural State University (national research university)”, 76, Lenin prospekt, Chelyabinsk, Russia, 454080 ** Veterinary hospital "Panetseya", 388, Pobedi prospect, Chelyabinsk, Russia,454100

Nowdays selective laser melting is used at various fields [1,2]. Its wide usage is explained by advantages such as the opportunity of forming of complex 3D elements and inner cooling channels; small amount of wastes of production. One of the most promising fields of medical usage of selective laser melting is production of bone implant made from biocompatible materials. Titanium was used as biocompatible material. Individual implants were formed at the device SINTERSTATION® PRODM125 SLMВ (Laser - CO2, lasered Power SP-200C-04, Max laser power – 200 W, Scanning speed - up to 1000 mm/s, Layer thickness - 20 -100 µm). At first the 3D model of the patient's (a small breed dog) skull with a defect after a traumatic brain injury was made by computed tomography. Based on the skull 3D reconstruction a 3D model of the missing fragment was created. Its geometric dimensions were defined that the formed missing fragment could be fixed on the skull at the following operation. For the same purpose, a perforation was made on the implant (Figure 1.). To check the conformity of the implant to the skull defect and to increase the level of preoperative planning, in addition to the missing fragment, a part of the skull was made (Figure 1). This gave an opportunity to surgeons to carry out detailed pre-operational planning. The next step of this work is carrying out a surgical operation to close the cranium with an individual implant.

Fig. 1. Part of the skull and implant

REFERENCES [1] Yasa, E., Kempen, K., Kruth, J.-P., Thijs, L. et al., // 21st Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2010:383-396, 2010. [2] Uriondo, A., Esperon-Miguez, M. and Perinpanayagam, S., // Journal of Aerospace Engineering 229(11):2132-2147, 2015, doi:10.1177/0954410014568797

1The research was supported in part by the Ministry of Education and Science of the Russian Federation № 3.9684.2017/BCH (2017122-GZ) for support of research at the South Ural State University)

584 ______Non isothermal methods for materials synthesis SHOCK-WAVE SYNTHESIS IN POWDER MIXTURES1

I.V. SAIKOV*, M.I. ALYMOV, S.G. VADCHENKO, P.YU. GULYAEV** *Merzhanov Institute of Structural Macrokinetics and Materials Science (ISMAN), 8 Academician Osipyan str., Chernogolovka, 142432, Russia, [email protected], +74965246372 **Yugra State University, 16 Chekhov str., Khanty-Mansiysk, 628012, Russia

The actual direction of materials science is the development of promising reactive materials which are mixtures of powders of metals, nonmetals and various ligaments (matrices). Reactive materials are characterized by ability to intensive release of thermal energy at shock-wave influence. Direct instrumental measurements at explosive loading are considerably complicated. Thus, most of such studies are purely experimental. Nevertheless, the processes of explosive loading of Al-S, Al-Tf and Al-Tf-C systems in the recovery fixtures were numerically studied in an axisymmetric formulation in [1]. The authors have chosen the values of explosive loading parameters. The work is aimed to finding the laws and conditions for the shock-wave initiation of energy condensed systems based on mixtures of metals with fluoroplastic. Both high-density compositions based on tungsten with various metals and light systems such as titanium + boron, nickel + boron nickel + aluminum, hafnium + boron are considered. Preliminary, the estimated thermodynamic calculations for all systems in the THERMO program were carried out [2]. As a result, data on adiabatic combustion temperature, specific volumes of gaseous products, the ratio of the mass of molten to the mass of solid products, and the most likely final products of the reaction were obtained. Calculation of equilibrium characteristics is based on minimizing of the system thermodynamic potential which expression accounts for the contributions of thermodynamic potentials for all the components present in the system, providing their concentrations. Algorithm for minimizing of the thermodynamic potential is based on the method of gradient descent. A wide range of compositions is considered from the point of view of their adiabatic combustion temperatures: from 1463 K for (Cu-Al-C2F4) to 3553 K for (Hf-B-C2F4). The experiments on shock-wave initiation by means of explosive were made according to two schemes: compaction in cylindrical recovery fixture and loading by a flyer. Tungsten-based systems proved to be difficult to initiate by shock-wave loading. X-ray phase analysis recorded a significant (more than half) tungsten residue with a small amount (less than 10%) of W2C. At the same time metal-additive (Al, Hf) rather actively reacted with fluorine from teflon with formation of AlF3 and HfF4 fluorides. There are not traces of interaction with Teflon (carbides, fluorides) in products from compositions based on nickel, copper and niobium. Compositions Ni–Al, Ni–Al–C2F4, Ti-B-C2F4, Hf-B-C2F4 most fully reacted (without the rest of the base metal). The main products in compositions based on nickel and aluminum are NiAl. Introduction of fluoroplastic in the system leads to the appearance of AlF3 in addition to NiAl and Ni2Al3. The essential role of the "activating" additives (Al, Ti, B) is experimentally shown to initiate, pass a chemical reaction in the powder mixture and the final phase formation. REFERENCES [1] Zelepugin S.A., Zelepugin A.S., Ivanova O.V., Yunoshev A.S. // Journal of Physics: Conference Series.  2017.  894.  №1. p. 012033. [2] http://www.ism.ac.ru/thermo/ [3] Alymov M.I., Vadchenko S.G., Saikov I.V.,. Kovalev I.D. // Inorganic Materials: Applied Research. – 2017. – 8. – №2. – p. 340 – 343. [4] Saikov I.V., Alymov M.I., Vadchenko S.G., Kovalev I.D.. // Letters on materials. – 2017. – 7. – №4. – p. 465 – 468.

1 This work was financially supported by the Russian Foundation for Basic Research (project no. 16-03-00777а

585 ______Combustion waves: theory and experiment MACROKINETICS OF COMBUSTION OF LAYERED COMPOSITIONS WITH A LOW- MELTING INERT LAYER

V.G. PROKOF’EV*, T.I. KHUDYAKOVA* *Tomsk Scientific Center, 10/4 Akademicheskii Pr., Tomsk, 634055,Russia, [email protected], 83822529845

Synthesis of layered compositions is one of the promising directions in the area of SHS [1]. To conduct this process, an initial layered structure should include different reacting mixtures to initiate combustion in parallel or perpendicular to the plane of coupled layers. In addition to the thermal and chemical interaction between the layers of the composition, there are accompanying processes of melting, crystallization and capillary wetting. The combination of strong and weak exothermic layers is used to conduct the synthesis, using the «chemical furnace» method. To obtain composite materials in the combustion mode, a sample is prepared from a mixture of reacting and inert powders. The synthesis product is a material that consists of reaction products enclosed in an inert material matrix. The limitation of this method is to meet necessary and sufficient conditions for the self-propagating mode of synthesis. The structure of the material synthesized depends on the ratio between the dimensions of inert and reacting layers, the adiabatic combustion temperature, the thermophysical characteristics of materials, the parameters of phase transition, and the conditions for heat exchange with the environment [2]. The obtaining of a composite material with a gradient structure by the SHS method is based on melting of an inner layer and flowing of a metal melt into the porous structure of outer layers due to the action of the capillary forces. The melt flow depth that determines the structure of the composite depends on the pore size, surface tension, phase transition parameters and temperature distribution. The required structure of the synthesized product can be obtained by changing the ratio between the layers of the composition. Calculating the propagation of combustion fronts, melting, impregnation, and crystallization includes solving the heat conduction and chemical transformation equations in various regions with moving boundaries (Fig. 1).

Li/Li0 1.2

0.8 1

2 0.4

0 0 2000 4000 6000 8000  Fig. 1. Relative thickness of the inner layer in the non-adiabatic combustion mode REFERENCES [1] A.G. Merzhanov // Dokl. Akad. Nauk.  2010.  V. 434.  № 4. pp. 489-492. [2] V.G. Prokofiev, V.K. Smolyakov // Combust., Expl. Shock Waves.  2016. – V. 52. – № 1. pp. 62-66.

586 ______Combustion waves: theory and experiment COMBUSTION CHARACTERISTICS OF MODEL COMPOSITE PROPELLANTS WITH ALUMINUM DIBORIDE1

O. G. GLOTOV*, G. S. SURODIN*, V. E. ZARKO*, M. A. KORCHAGIN** * Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of Sciences, Institutskaya 3, Novosibirsk, 630090, Russia, [email protected], +7-383-3332292 ** Institute of Solid State Chemistry and Mechanochemistry Siberian Branch of the Russian Academy of Sciences, Kutateladze 18, Novosibirsk, 630128, Russia

The work continues comparative investigations [1] of highly loaded model propellant formulations with ca. 40 % of different boron containing fuels. This work is focused on aluminum diboride and mechanoactivation effects. A research objects – three model propellants based on ammonium perchlorate, energetic binder and combined fuel. First fuel, MA1, – “raw” material – is mechanically-activated (MA) mixture of aluminum and boron powders taken in the same mass ratio as in aluminum diboride. Second fuel, MA2, is aluminum diboride made of this “raw” material via method close to one described in [2]. Third fuel, MA3, is MA2 subjected again to mechanical activation. Thus, we compared three fuels of AlB2-type obtained with different MA-actions. The data on the burning rate at pressures of 1.2 MPa and 2.5 MPa and on the condensed combustion products (CCP) parameters are reported in present work. For the particles extinguished near the burning surface the oxidation of fuel on and above the surface is actually investigated [3, 4]. Sampled particles are so called primary CCP [5]. The particles mass size distributions in the range from 0.5 microns to millimeters are delivered; the CCP particles morphologies (obtained via optical microscopy, SEM, EDS) are described. The millimeter-sized products are the skeleton-layer or carcass remaining in a glass after propellant specimen burned out. The data on the combustion completeness of fuel was obtained via cerimetric method [6]. The approaches to compare fuels in mass parameters of the combustion products and in efficiency of energy release are developed. For the analysis of data on combustion completeness the complex parameter E is proposed named “efficiency of the energy release”. This parameter integrates the incompleteness of fuel combustion, the mass fractions of Al and B in the combined fuel, the reducing number and the specific heat of combined fuel, as well as the mass of carcass residue in a glass. In general, the efficiency of the energy release E essentially depends on the burning rate value and on the agglomeration process features as well as on the propellant formulation and the combined fuel parameters. The propellant with fuel MA3 was most energy release efficient among three formulation under study.

REFERENCES [1] Glotov O. G., Zarko V. E., Surodin G. S., Kiskin A. B. // Energetic Materials – Reactivity and Modeling. 48th International Annual Conference of the Fraunhofer Institute for Chemical Technology (ICT), Karlsruhe, Germany. – 2017. – P. 14-1–14-14. [2] Korchagin M. A., Zarko V. E., Bulina N. V. // Eurasian Chemico-Technological Journal. – 2017. – V. 19. – № 3. P. 223-229. [3] Glotov O. G., Zyryanov V. Ya. // Combustion, Explosion and Shock Waves. – 1995. – V. 31. – № 1. P. 72–78. [4] Korotkikh A. G., Arkhipov V. A., Zarko V. E., Kiskin A. B. // Combustion and Flame. – 2017. – V. 178. – P. 195–204. [5] Liu J., Liang D., Xiao J., Chen B., et al // Combustion, Explosion and Shock Waves. – 2017. – V. 53. – № 1. P. 55–64. [6] Fedotova T. D., Glotov O. G., Zarko V. E. // Propellants, Explosives, Pyrotechnics. – 2007. – V. 32. – №2. P. 160–164.

1 The reported research was partially funded by Russian Foundation for Basic Research, grant № 15-03-04321.

587 ______Combustion waves: theory and experiment FEATURES OF HIGH-TEMPERATURE COMBUSTION OF LAMINATE METAL SYSTEMS

V V . G . SALAMATOV , A.I. KIRDYASHKIN, R.M. GABBASOV Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], 79059911967

Deep understanding the mechanism of high-temperature combustion in metallic systems is important both for predicting the combustion of rocket fuels [1] and for conducting the directed SHS of functional inorganic materials [2]. High temperatures in combustion waves (about 3000 K and more) often lead to the melting of condensed phases, initial components and products. Here, the effects of capillary convection in melts play an important role. It should be noted that these effects have not been fully investigated yet.

Another important aspect is nonthermal emission phenomena in reaction waves [3, 4]. At present, there is no comprehensive understanding of these phenomena which can not be explained in the framework of available models for heterogeneous combustion [2]. This work represents a complex study of the thermal, structural, and emission dynamics during the combustion of Ni-Al, Cu-Al, Ti-Al wire composites (media: argon, oxygen, air) and Ti, Ni, Al wires (medium: argon, air). Combustion was initiated by fast passing an electric current through a sample placed between electrodes until melting and breaking of the central part. Two combustion waves in the form of drops of

reacting melts were propagated along the sample towards the electrodes. The process was monitored by high- speed video recording, spectrometry, spectral pyrometry and electroprobe plasma measurements [5]. The studies have shown that there is the complete melting of metals and reaction products in the combustion wave. This is confirmed by the high value of the measured maximum combustion temperature (2500÷5600 K, the maximum value corresponds to the synthesis in oxygen). Propagation of waves is accompanied by specific hydrodynamic and emission effects. Hydrodynamic effects. The processing of video recording data showed that the combustion rate of the systems increased from 0.20 to 0.92 m/s during the transition from the inert to oxidizing media. The data obtained demonstrate that high values of combustion rates are caused by capillary convection of melts in the reaction wave [6]. The conclusion is confirmed by the observations of dynamics for the development of flows in the form of liquid circulation cells (vortices, ordered cells (polyhedrons) with a size of up to 0.2 mm) on the surface of the drops of reacting melts. The velocity of flows is ~ 2 m/s. Emission effects. Analysis of video recording has shown that components evaporate uniformly over the entire surface of a reacting drop during the combustion of composites in Ar. During the combustion of

composites in oxidizing media, evaporation is supplemented by jets from the reacting drop. Here, apparently, there is the boiling of a melt. In some cases, jets are accompanied by the dispersion of the drop (Cu-Al, Ni- Al). Jets of vapors burn and form the clouds of dispersed particles (gas-and-dust phase). A feature of the formation of a gas-dust phase is the effect of twisting the jet streams around a reacting drop. This indicates strong electrical polarization of the system (drop and gas-and-dust phase). The potential difference between the drop and the gas-and-dust phase, according to the calculations, is not less than (2÷3) 103 V. The atomic and molecular spectra of Al, Ni, Al+, Cu, Ti, AlO, NiO, CuO and other particles are observed during reaction transformations. The measured current-voltage characteristics of emission current showed that the electron temperature of plasma reached the level of (1.5÷20) 104 К. REFERENCES

1] A.G. Merzhanov, A.S. Rogachev // J. Pure and Applied Chemistry. –1992. – 7. 941－953. 2] L. H. Cavery, R. L Click // J. Spacecraft and Rockets. – 1967. 1. 79－85. 3] A.I. Kirdyashkin, V.L. Polyakov, et al. // Combustion, Explosion and Shock Waves. – 2004.–40. 180－185. 4] A.I. Kirdyashkin, V.G. Salamatov, et al // Doklady Physical Chemistry. –2014. – 454. 5－7. 5] F.F. Chen // Electric Probes in "Plasma Diagnostic Techniques". – New York: Academic Press, 1965, Chap.4. 113－200. 6] H. Linde, P. Schwarz, H. Wilke // Lecture Notes in Physics. – 1979. –105. 75－120.

588 ______Combustion waves: theory and experiment COATING COMBUSTION SYNTHESIS CONTROLLED BY MOVING ELECTRON BEAM 1

A.G. KNYAZEVA*,**, O.N. KRYUKOVA** * Tomsk Polytechnic University, Lenina avenue, 30, Tomsk, 634050, Russia, [email protected] ** Institute of Strength Physics and Materials Science of SB RAS, pr. Akademicheskii, 2/4, Tomsk, 634055, Russia

The methods of materials synthesis using combustion or Combustion Synthesis (CS) (Self propagating High temperature Sythesis (SHS), Thermal Explosion (TE)) allow obtaining the materials with different properties [1,2]. Combustion synthesis processes are characterized by high-temperatures, fast heating rates and short reaction times [3]. This is interested for the technologies of intermetallic or composite coating deposition. Today this is interested for the development of Additive Manufacturing (AM) technologies [4-6]. When electron-beam is used for intermetallic coating or detail formation, the features appear [7,8]. In this paper, the some models of authors are discussed applicable to electron beam melting of metals forming intermetallic phase and composite formation controlling by electron beam. Firstly, the possibility of self-propagating mode under the conditions of coating synthesis on substrate is presented. The kinetics of exothermic reaction is described in this model by summary reaction scheme; however the coupling between mechanical and thermal processes is taken into account. The problem on stationary reaction front propagation is solved analytically using asymptotic method, similarly to [9,10]. The simplest model is generalized further to composite synthesis when reaction mixture contains inert inclusions. When green powder mixture is low–energy, self-sustaining mode is not possible. However, using electron-beam one can use to control the synthesis. The corresponding model includes thermal conductivity equations with two heat sources – from electron-beam heating and from chemical reaction. Different variants of the model are studied in [11-13], where the coupling effect was shown on the coating composition formation under electron-beam controlling taking into account the detailed reaction kinetics; the phase formation in the melting pool during particle dissolution in direct metal deposition technology was demonstrated; critical phenomena dividing the composite and homogeneous coating formation were detected. During recent years, the models with detailed kinetics were refined to take into account shrinkage effect. It was demonstrated, for example in [14-16], that similar model obey prognostic properties and can predict irreversible composite change during coating and objects formation in AM-technologies.

REFERENCES [1] Varma A, Rogachev AS, Mukasyan AS, Hwang S. // Adv Chem Eng.  1998  24  79–226. [2] Kashinath C. Patila, S.T. Arunab, Tanu Mimani // Current Opinion in Solid State and Materials Science.  2002.  6.  507– 512. [3] Patil KC, Aruna ST, Ekambaram S. // Current Opinion in Solid State and Materials Science.  1997. 2. 158–163. [4] S.L. Sing, L.P. Lam, D.Q. Zhang, Z.H. Liu, C.K. // Materials Characterization.  2015.  107.  220–227. [5] Fei Weng, Huijun Yu, Chuanzhong Chen, Jianli Liu, Longjie Zhao, Jingjie Dai // Journal of Alloys and Compounds.  2016.  686.  74-81. [6] Shishkovsky I.V. // Laser-controlled intermetallics synthesis during surface cladding.  in Laser Surface Engineering. Processes and Applications. A volume in Woodhead Publishing Series in Electronic and Optical Materials.  Elsevier. 2015.  237–286. http://dx.doi.org/10.1016/B978-1-78242-074-3.00011-8 [7] Murr L.E. // Additive Manufacturing. 5 2015.  .  40–53. [8] Schiller S. and Panzer S.// Ann. Rev. Mater. Sci.  1988.  18.  121-140. [9] Timokhin A.M., Knyazeva A.G. // Chemical physics. – 1996. – 15. – 10. – 85-100 [10] Knyazeva A.G., Sorokova S.N. // Combustion, Explosion, and Shock Waves. – 2006. – 42. – 5. – 549-558 [11] Sorokova S.N., Knyazeva A.G. // Theoretical Foundations of Chemical Engineering. – 2010. –.44. – 2. –172–185 [12] Knyazeva A.G., Pobol I.L., Gordienko A.I., Demidov V.N., Kryukova O.N., Oleschuk I.G. // Phys. Mesomech. – 2007. – 10. – 3-4. – 207-215 [13] PMTF [14] Knyazeva A.G., Kryukova O.N. // IOP Conf. Series: Journal of Physics: Conf. Series – 2017. – 899. – P 072001. [15] Knyazeva A. // Journal of Physics: Conference Series. – 2016. – 754 . – 042009 [16] Knyazeva A.G., Pobol I. L., Demidov V.N. // IOP Conf. Series: Materials Science and Engineering. – 2016. – 140. – 012021

1 The work is supported by Russian Science Foundation (RSF), grunt number 17-19-01425

589 ______Combustion waves: theory and experiment FORMATION OF METAL-CERAMIC COMPOSITES USING SHS IN TI-AL-C SYSTEM1

M.G. KRINITCYN1,2, G.A. PRIBYTKOV1, A.V. BARANOVSKIY 1 Institute of Strength Physics and Materials Science SB RAS, Tomsk, 2/4, pr. Akademicheskii, Tomsk, 634055, Russia [email protected] 2Tomsk Polytechnic University, Tomsk, Lenina str., 30, 634050

During the work on SHS in the titanium-carbon system, TiC-Ti powder composites were obtained and investigated. Composites were obtained after combustion of mixtures with a calculated content of an additional inertness of 30 to 60 vol.%. X-ray phase analysis of the obtained SHS products showed that in the samples with a calculated binding content of 30 and 40 vol%, there is no binding completely, and the lattice parameter of titanium carbide in these samples is below the tabulated value for titanium carbide TiC, indicating that samples form nonstoichiometric titanium carbide. Titanium carbide TiCx has a wide range of homogeneity. Carbon content in carbide at temperatures in the vicinity of the melting temperature of titanium on a double equilibrium diagram varies from the equiatomic composition (stoichiometric coefficient X = 1) to X = 0.5. Since all the reaction mixtures studied by us have an excess of titanium, titanium carbide should in all cases have a non-stoichiometric composition in accordance with the equilibrium diagram. The maximum combustion temperature for samples with a calculated binder content of 60 vol% is close to the lowest possible start temperature of the SHS process for this system. This limits the composition of the initial mixtures. To modernize this system, aluminum was added up to 40% by volume in powder mixtures of titanium and carbon with a calculated titanium inert content of 50% by volume. In addition to layer-by-layer combustion, the powders of this system were burned using the technology of thermal explosion. Before the thermal explosion, the powders were mechanically activated in the "Activator-2s" planetary ball mill. The structure and phase composition of the resulting powders were studied. The resulting powders were examined using a scanning electron microscope LEO EVO 50 (Zeiss, Germany), a transmission electron microscope JEOL JEM-2100 (Tokyo Boeki Ltd., Japan) and a metallographic optical microscope AXIOVERT-200MAT (Zeiss, Germany). The determination of the elemental composition was carried out by the EDX method with the scanning electron microscope LEO EVO 50, the phase composition was determined using the X-ray diffractometer DRON-07 (Bourevestnik, Russia). All of the above equipment is based on the NANOTEH Center for collective usage ISPMS SB RAS (CCU TNRC SB RAS). It is established that the structure of powders obtained by the SHS method is close to the structure obtained without aluminum. In the thermal explosion, the structural components remain the same, but the size of the carbide particles decreases (Fig. 1). Aluminum in all cases completely reacts with titanium to form the corresponding intermetallides.

a b Fig. 1. Morphology of the Ti-Al-C (a) and Ti-C (b) powder, obtained by SHS

1 This work was funded by Russian Scientific Foundation (project No. 17-19-01425).

590 ______Combustion waves: theory and experiment MODELING OF THE COMBUSTION SYNTHESIS OF TITANIUM BASED COMPOSITE WITH DETAILED REACTION SCHEMA 1

YU.A. CHUMAKOV*, A.G. KNYAZEVA*,** * Institute of Strength Physics and Materials Science of SB RAS, Tomsk, ,634055 Russia ** National Research Tomsk Polytechnic University, Tomsk, 634050, Russia

Self-propagating high-temperature synthesis (SHS) is one of the methods of composite manufacturing based on titanium including titanium carbides, borides and silicides. However, this process is nonequilibrium process and it is not possible to predict the composition of the synthesized product due to the presence of a wide range of homogeneity on the phase diagrams of some systems. Therefore, the aim of this work is to develop a model and theoretical study the synthesis of the titanium-based composites in the combustion regime with detailed reaction kinetics. The mathematical model of the process of the reaction initiation in the powder mixture of metal (Ti) and boron (B) is studied. The sample is a cylinder of radius r consisting of two layers of pressing powders (figure.1). We assume that layer 1 (igniter) is a stoichiometric mixture of Ti and Si powders and the thickness of this layer is l. The second layer of thickness L (reaction mixture) consists of the mixture of Ti and boron C powders. We assume also that titanium in the second mixture is presented in excess, so that it is not completely consumed in the reaction. We consider the chemical transformations in the first system are described by the total reactions scheme "reagent-reaction product"

5Ti  3Si  Ti 5 Si3 Four-step reaction proceed in the second layer I. Ti+2B→TiB2; II. Ti+B→TiB; III. TiB+B→TiB2; IV. 2TiB+TiB2→Ti3B4.

Fig. 1. Scheme of process The heat losses to the environment by convection and thermal radiation are taken into account. Titanium excess consumes the heat and plays a role of an inert component. This is formally taken into account through the heat capacity. We consider the kinetic equations corresponding to the reaction with strong retardation of layer reaction product. The melting of the components was considered by taking into account the changing of effective heat capacity and density in the vicinity of the melting temperature. Since the structure of the powder system is changing and is unknown at any time, we use the rule of the mixture to calculate the effective properties of initial substance and synthesized composite. The effective coefficient of thermal conductivity of the mixture was calculated similarly. As calculations showed, an increase in excess titanium leads to some decrease in the temperature in the second reaction layer and to the reduction of the velocity of the reaction front propagation that qualitatively corresponds to the experiment. The stationary combustion wave in the igniter is not formed.

1 This work was supported by Russian Science Foundation (RSF), grunt number 17-19-01425

591 ______Combustion waves: theory and experiment HIGH-SPEED VISUALIZATION OF COMBUSTION SYNTHESIS DISCRETE REACTION WAVES: COHERENT HEAT MICROSTRUCTURES1

BORONENKO M.P., GULYAEV P.Y., DOLMATOV A.V. Yugra State University

The paper shows new possibilities for studying the effects of microheterogeneous combustion by the method of high-speed micro-thermal imaging. On each video frame, the area of the microfocal reaction has been identified, where local superadiabatic heating takes place. All the discrete regions of heat generation were combined on a common image of the thermal microstructure of the combustion reaction wave. The characteristic size of the foci of combustion in the Ni-Al system was from 150 to 300 µm, which is 5 times larger than the size of the largest powder particles. It was found experimentally that the combustion front propagates only in the local regions of superadiabatic heating and the motion has a discrete step. The thermal microstructure has the form of a quasiperiodic sequence of layers, the spatial direction of which weakly depends on the position of the combustion front with respect to the horizontal. To verify this fact, which contradicts the classical theory of wave stability in the spin combustion mode, the differential chronoscopic analysis of the interframe difference in the motion of the combustion front line was selected. As a result, it was shown that, independently of the geometry of the combustion front, a synchronous and quasi-periodic occurrence of new local combustion sites is observed. The period of thermochemical induction between each discrete step of motion was 0.1 to 0.2 ms. Thus, the data of the 2D thermal map of differential chronoscopy (DСS) allow visualization of the SHS combustion wave in the form of coherent thermal structures with quasiperiodic parameters. At the end of the paper, an example is given of processing a 2D DСS map using Fourier and Trace-transforms to extract statistical indicators of unstable combustion conditions.

1 The reported study was funded by RFBR according to the research project No. 18-08-01475.

592 ______Combustion waves: theory and experiment CHRONO-TOPOGRAPHIC ANALYSIS OF THE FIRE FOCUS DYNAMICS IN THE SHS WAVE1

A.V. DOLMATOV*, P.YU.GULYAEV*, I.V. MILYUKOVA* * Ugra State University, Chekov st, 16, Khanty-Mansiysk, 628011, Russia, [email protected], +79505001390

On the basis of the Ni-Al system, an experimental study of the evolution of individual foci in the SHS wave was carried out. The combustion control was carried out by an original micro thermal imaging system with a spatial and temporal resolution of 5.8 μm and 1 msec respectively (Fig. 1) [1]. To study the dynamics of foci of combustion along the front of the SHS wave (in the X direction), the original technique of chrono- topographic analysis was applied [2]. It allowed: to track in a discrete medium points with identical stages of high-temperature synthesis and to study the dynamics of their spatial distribution; to identify individual foci in the images and determine the statistical distribution of their parameters in the SHS process (Fig. 2).

t=0.016 s t=0.029 s t=0.041 s

t=0.053 s t=0.066 s t=0.079 s

t=0.094 s t=0.106 s t=0.119 s Fig. 1. Frames of micro-thermal imaging: the vector Y is the normal to the front of the SHS wave; the dimension of the viewing area in the X direction is 7.3 mm, in the Y direction 1.87 mm.

Fig. 2. Chronographic map of the SHS process: shows the shift of the reaction boundary ΔY in the cross section X0 at time t0 According to the chronological map of the SHS process, it is found that the development of foci along the wave front is similar to the propagation of the very front of the reaction - there is a stage of rapid displacement of the boundary of the fire focus with a sharp increase in temperature in it (flash stage), and the stage of inhibition, accompanied by a decrease in temperature. Moreover, the transition from the stage of inhibition to a flash causes the creation of a secondary fire focus, which propagates along the front of the SHS wave, but in the opposite direction with respect to the primary fire focus. The spread of secondary foci is unstable and ceases after a while. REFERENCES [1] Boronenko, M.P., Seregin, A.E., Gulyaev, P.Yu., Milyukova, I.V. // Scientific Visualization.  2015.  V.7.  pp. 102-108. [2] Dolmatov A.V., Berestok G.M. // Bulletin of Ugra State University.  2017.  V.3(46).  pp. 64-73.

1 The work was carried out within the framework of RFBR project No. 18-08-01475 "Development of optical nanosecond resolution methods for determining unstable combustion wave regimes in self-propagating high-temperature synthesis of materials".

593 ______Combustion waves: theory and experiment IMPROVE HEAT EXCHANGE EFFICIENCY IN CONDENSING BOILERS WITH RADIATION BURNERS

K.A. TSOY*, K.A. SHTYM*, A.V. KULIK*, E.F. KIKHAIOGLO* * Far Eastern Federal University, Suhanova St. 8, Vladivostok, Primorsky Krai, 690950, Russia, [email protected], +79243296747

Increasing the efficiency of heat transfer processes in furnace devices and convective heat exchangers is one of the promising tasks of modern boiler construction [1, 2]. As shown by experimental studies [3,4], the use of radiation burners with NiAl intermetallides porous nozzles is one of the ways to increase the technical and ecological characteristics of boilers. Traditionally, the designing of heat exchangers for boilers is carried out according to empirical dependencies obtained experimentally. These dependencies consider many factors such as the height of the burner arrangement, the degree of contamination of the combustion walls, and the layout of the heating surfaces [5]. However, the main criterion for empirical calculations remains the emissivity of the mixture of gases - the combustion fuel products. The application of these calculations in the case of boilers with radiation burners is not correct, since the source of radiation in them is solid heat, in addition to gases. The experimental setup include NaAl porouse burner, water and air supply systems. Fuel - propane / butane 50/50%. Porous burner with preliminary mixture formation by fan and gas nozzles. Combustion mode - internal. Heating surfaces - tubes filled with circulating water at a temperature of 15 °C at the inlet. The combustion chamber consists of radiation-convection heating surfaces with a staggered order of pipelines diameter 22/20 mm. Then - convective heating surfaces also arranged in staggered order. Water inlet into the combustion chamber pipelines. The water temperature is measured at the inlet to the setup, between the combustion chamber and convective part, and at the outlet from the setup. The air temperature is measured at the inlet, the combustion products temperature measured in the outlet from the combustion chamber, and at the outlet of the setup. This arrangement of measuring apartments allows making a complete picture of the distribution of heat flows in this prototype boiler. According to the results of the conducted experiments, with the obtained conversion coefficient of heat to radiation 44.2%, the efficiency of the unit at the highest calorific value is 89%. The gas temperature at the setup outlet is 80 °C. The heat stress of the furnace space is 5.24 MW / m3. In order to intensify the heat transfer in the furnace volume, it was decided to replace the pipelines of radiation-convective heating surfaces with corrugated pipes with diameters of 13/15mm. The number of pipelines along the length increases by 15%, the total water and gas volumes remain unchanged. The increase in the heat-receiving surface estimated at 20%. The gas temperature at the setup outlet decreased to 60 °C. The heat stress of the furnace space increased to 6.6 MW / m3. Efficiency by HCV increased to 93%. In connection with the transition of the setup to the condensation mode, was decided to return the condensate by means of a submersible pump with further spraying it on radiation-convective heating surfaces. The gas temperature at the setup outlet decreased to 45 °C. The heat stress of the furnace space increased to 8.8 MW / m3. Efficiency by HCV increased to 96%. The conducted experiments, with a burner power of 15 kW, showed: 1. The experimentally determined heat stress of the furnace boiler room with radiation burners reaches 8.8 MW / m3, which is 4 times more than in the furnaces of traditional boilers. 2. The expansion of the surface of the radiation-convective packet is proportional to the increase in the efficiency of the perception of heat transmitted by radiation. 3. Spraying of the returned condensate in the radiation-convective package also allows increasing the efficiency of the setup. REFERENCES [1] Aldushin AP , Merzhanov AG, Filtration combustion theory : general concepts and state of research // Distribution of heat waves in heterogeneous environments . Novosibirsk: Nauka. - 1988. - 9-52. [2] Kirdyashkin A. I. et al. Energy and spectral characteristics of radiation during filtration combustion of natural gas //Combustion, Explosion, and Shock Waves. – 2010. – Т. 46. – №. 5. – 523-527.. [3] Kirdyashkin, A., Guschin, A. N., Maznoy, A. S., Minaev, S. S., & Palesskiy, F. S. (2014). Combustion-synthesized porous Ni-Al materials for radiative porous burners. In Advanced Materials Research. (Vol. 1040,442-447). [4] Fursenko R., Maznoy A., Odintsov E., Kirdyashkin A., Minaev S., Sudarshan K. Temperature and radiative characteristics of cylindrical porous Ni-Al burners // International Journal of Heat and Mass Transfer 2016 (98) 277-284. [5] Thermal Design of Boiler Units (a Standard Method) Energiya, M. 1973 (in Russian).

594 ______Combustion waves: theory and experiment DYNAMICS OF FLAME OSCILLATIONS IN NARROW SOLID FUEL SAMPLES WITH HEAT LOSSES1

V.V. GUBERNOV*, V.N. KURDYUMOV** *P.N. Lebedev Physical Institute, 53 Leninsky pr., Moscow 119991,Russia, [email protected] Far Easten Federal University, 8 Suhanova st., Vladivostok 690950, Russia **Department of Energy, CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain

The emergence of oscillatory (diffusive-thermal) instabilities due to the Poincaré–Andronov–Hopf bifurcation is well known in combustion of solid fuels. One-dimensional pulsations in the propagation of combustion waves were found in experiments on Self-Propagating High-Temperature Synthesis, combustion of thermites and gunpowders [1–3]. The influence of heat-losses on the flame dynamics in narrow samples of energetic material is investigated numerically. The model is considered in a one-dimensional form with the one-step irreversible Arrhenius reaction mechanism. A typical C-shaped response curve is found for the dependence of the flame- propagation velocity on the heat-loss parameter, with solutions along the lower branch of slower flames being always unstable. It is found that a part of the upper branch of the C-shaped response curve is also unstable and the Poincaré–Andronov–Hopf bifurcation takes place at a certain value of heat-loss intensity even if the steady state solution is stable under the corresponding adiabatic conditions. The numerical simulations show that an increase in heat-losses induces, for sufficiently high Zel’dovich numbers, the Feigenbaum’s cascade of period doubling bifurcations after which a chaotic dynamics is setting in.

Fig. 1. Oscillations of instant velocity of combustion wave for Zel'dovich number 8 and certain value of the heat loss parameter illustrating the flame quenching via chaotic pulsations.

The chaotic dynamics precedes the flame extinction occurring for the further increase of the heat-loss parameter which, nevertheless, remains significantly lower than the steady extinction limit dictated by the C- shaped response curve. The flame quenching via the chaotic oscillations is illustrated in Fig. 1. Apparently, the parametric dependence of the extinction time in these cases is also irregular with appreciable disparities in magnitude. Finally, the intermittency effect is detected slightly below the extinction limit with irregular dynamics alternating by apparently periodic stages. These results may be important for the flammability limits theory and practical fire safety applications.

REFERENCES [1] A.F. Belyaev, L.D. Komkova// Zh. Fiz. Khim., 1950, 24, 1302–1311. [2] L.B. Maksimov// Zh. Fiz. Khim., 1963, 37, 1129–1332. [3] V.M. Shkiro, G.A. Nersisyan// Combust. Explos. Shock Waves, 1978, 14, 121–122.

1 This work was supported by RFBR grant No. #16-03-00758

595 ______Combustion waves: theory and experiment CHEMICAL FEATURES OF COAL PARTICLES THERMAL DECOMPOSITION AND COMBUSTION: MODELS AND EXPERIMENTS1

А.А. PONOMAREVA*, I.V GREBENYUK*, A.V. LESNYKH*, K.A. TSOY*, V.I. BABUSHOK*,**, K.A. SHTYM* * Far Eastern Federal University, Suhanova St. 8, Vladivostok, Primorsky Krai, 690950, Russia, [email protected] ** KTC Consulting, Gaithersburg, MD, 20878, USA

Highly efficient combustion of low-grade coals in boilers of thermal power plants is one of the most important and urgent problems of the energy sector [1, 2]. To work out practical recommendations on choosing rational modes of burning of solid organic fuels, it is necessary to establish a relation between the quality factor of coal and the characteristics of various stages of its thermochemical conversion [3]. Many experimental studies have shown that coal pyrolysis involves interactions of chemical and physical processes. In literature there are many models to describe the chemical reactions during coal pyrolysis, including singlestep and multistep kinetic chemical models, the distributed activation energy models, the group-depolymerization, vaporization, and cross-linking model, the chemical percolation model for devolatilization and others [4]. In this work literature analysis and experimental investigations were combined to find an adequate theoretical model of coal particle chemical and physical transformation during heating. Fine brawn coal particles with the size less than 120 µm were used for experiments. Firstly, the thermophysical characteristics such as the humidity, the ash content, and the lowest calorific value were determined. Secondly, thermal decomposition products compositions of finely grained coal and temperature ranges of outlet gases were estimated. The humidity and ash content were determined using standard methods (GOSTs: Р 52911-2013, 11022-1995). For these procedures, a muffle furnace with a heating temperature of up to 1000ºC and a drying oven were used. The lowest calorific value was measured by Calorimeter IKA C 6000 (IKA -Werke GmbH & Co, Germany). IR specters of thermal decomposition gas products were recorded using the Nicolet iS10 FT-IR Spectrometer (Thermo Electron Corporation, USA). For this aim, this equipment has a special gas-cuvette and the temperature-maintaining unit. The experiments were carried out in a chamber at atmospheric pressure in the air. Samples were heated to 800℃ with a heating rate of 5℃/min and maintaining a maximum temperature of 1.5 hours. Outlet gases came out into separate gas line heated up to 180℃ connected to the spectrometer. Thus, the IR absorption maxima for each detected component (H2O, CO2, CO, CH4) of gas mixtures were estimated, and the temperature zones for the various components formation were revealed. It's well known, coal is a typical natural porous media. It is very important to understand combustion behaviors of individual coal particles to achieve effective coal combustion control. The reaction processes in the coal combustion are roughly classified into a devolatilization process, caused by coal pyrolysis, and a char combustion process. In the coal heating process, it is well known that swelling occurs in the coal softening process. Coal pyrolysis and char combustion are accompanied by gas diffusion in pores, which has a significant impact on the product release and the yield. Furthermore, fragmentation occurs, causing the particle diameter to change suddenly in the latter period of the combustion process. However, it is very difficult to understand these coal combustion behaviors, because coal properties vary depending on the coal type, and the reaction occurs at high temperature and under complicated reaction fields. Many models allowing to describe coal particles thermal decomposition processes were analyzed. A numerical technique for estimating kinetic processes of thermochemical conversion of solid organic fuels [3], gas diffusion equations in fractal porous media by numerically simulating movements of molecules in pore models [5] and percolation model for simulation of coal combustion process [6] has attracted our close attention. REFERENCES [1] Tsoy K., Babenko G., Lesnykh A. // Scientific Review.  2017.  Vol. 2.  pp. 30–37. [2] Lesnykh A.V., Shtym K.A., Golovatiy S.V. // Vologdinskie Chtenija.  2012.  Vol. 80.  pp. 179–181. [in Russian] [3] Boiko E.A., Pachkovskii S.V., Didichin D.G. // Combustion, Explosion, and Shock Waves.  2005  Vol. 41.  № 1. pp. 47–56. [4] Chen Y., Ma L., He R. // Combust. Sci. Technol.  2014.  Vol.186.  pp. 747–765. [5] Cao, L., and He, R. // Combust. Sci. Technol.  2010. Vol. 182.  pp. 822–841. [6] Suzuki A., Yamamoto T., Aoki H., Miura T. // Proceedings of the Combustion Institute.  2002. Vol. 29.  pp. 459–466.

1 This work was supported by RFBR grant № 17-08-01207

596 ______Combustion waves: theory and experiment COMBUSTION SYNTHESIS OF SIALON CERAMIC IN FORCED OSCILLATION MODE1

A. MAZNOY, A. KIRDYASHKIN. Tomsk Scientific Center SB RAS, 10/4 Akademicheskii pr., Tomsk, 634055, Russia, [email protected], +79234124765

Organization the combustion synthesis of producing porous oxynitrides in forced filtration mode allows one to obtain porous ceramics at a nitrogen pressure less than 1 MPa [1]. In order to provide full conversion of the reagents into the ceramic during CS it is necessary to maintain high specific surface of powdered reagents. Therefore, melting and coalescence of the condensed phases in combustion wave zone should be avoided. Maximum combustion temperature control might be achieved by portion supply of the reacting gas. Filtration combustion synthesis was investigated using a powder mixture, which was normalized to yield β-sialon Si2Al4O4N4. Structure formation in the porous reaction samples was carried out as described in [1]. Samples with following parameters was used: cylindrical shape (d = 40 mm, h = 40 mm), mass of samples m0 = 100 g, Si2Al4O4N4 dilution rate φ = 0.45, porosity 65%. For combustion synthesis, an experimental setup schematically shown in [1] was used. Oscillation supply of fuel was carried out by means of the special valve intercepting the gas inlet into the reactor at a given frequency γ, which is defined as the number of "open/close" cycles per minute. Combustion synthesis was performed with following conditions: excess -1 pressure in reaction chamber P0 = 600-900 kPa, initial nitrogen mass flow Q0 = 0.26 g/s, γ = 5 min , filtration in coflowing configuration. During the synthesis the pressure in the reaction chamber cyclically oscillated from Pmin = 600 kPa to Pmax = 870 kPa. The combustion synthesis parameters (maximum temperature in the combustion wave Tm, combustion rate UC, the conversion rate ν) obtained in the above- mentioned experiment, as well as in experiments without forced oscillation with fixed values of pressure corresponding to Pmax = 870 kPa and Pmin = 600 kPa, are presented in Table 1. It was found out that in forced oscillation mode the maximum temperature in combustion wave zone reduces and conversion rate of the products increases. Table 1. Macrokinetic parameters of the combustion synthesis under various conditions o Conditions Tm [ C] UC [mm/s] ν -1 Oscillations γ = 5 min . Pmax = 870 kPa. Pmin = 600 kPa 1500 0.51 0.97 No oscillations, P = 870 kPa 2050 0.50 0.93 No oscillations, P = 600 kPa 1890 0.41 0.90 For the observed combustion rates the minimum required nitrogen intake into the reaction zone should be Qmin > 0.075 g/s. Figure 1 shows the dependence of the mass flow through the reaction chamber. When the valve overlaps the flowing stream, the gas flow through the reaction chamber m(t) takes negative values. It means that the gas flows out of the reactor. Apparently, the nitriding reaction in these moments is suppressed. Optimal conditions for the synthesis occur only in the periods when the valve is in the open position. Thus, reduction of the maximum temperature observed in experiments with forced oscillation of nitrogen supply is achieved due to kinetic limitations of the combustion. The combustion mode under discussion makes it possible to decrease the content of thermal diluents required for full conversion of the mixture into the products.

m, g/s 0.2 0.075 0.0

-0.2

60 120 180 240 t, s

Fig. 1. Experimental dependences of the net mass flow through the reaction chamber

REFERENCES [1] Maznoy A, Kirdyashkin A, Gabbasov R.. // International Journal of Heat and Mass Transfer.  2016.  95.  264-271.

1 This work was carried out within the state task of FASO (No. 0365-2018-0002)

597 ______Combustion waves: theory and experiment MATHEMATICAL MODELING OF POROUS MATERIAL SYNTHESIS SUPPORTED BY THE FILTRATION COMBUSTION OF A GAS MIXTURE

O O . V. LAPSHIN* , V. G. PROKOF’EV**

*Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], (8-3822)492294 **Tomsk State University, 36 Lenin Ave., Tomsk, 634050, Russia, [email protected], (8-3822)529852

Nomenclature of substances obtained by self-propagating high-temperature synthesis is limited by the green mixture requirements, the main of which is high exothermicity. This circumstance does not allow us to synthesize many substances with increased physical and chemical properties. Therefore, postheating of condensed components is a perspective method for the synthesis of materials from low-calorie mixtures [1 - 3]. For this purpose, filtration combustion of gas can be effectively used in a porous medium formed by granules from a powder mixture of condensed substances. Forced gas blow is conducted through porous permeable samples during filtration combustion. In this case, there is heat and mass transfer, which substantially intensifies the process of chemical transformations in the solid phase, and also allows us to vary the structure parameters of final products in the wide range. Combustion of gas in the pore space is controlled by the gas feed rate, the composition, filtration resistance, the parameters of heat exchange with a condensed phase and an external environment. These factors determine the dynamics and efficiency of porous material synthesis. This type of filtration combustion, covering a wide class of reacting systems, is called hybrid combustion [4, 5]. For example, the work [6] provides a two-temperature mathematical model of hybrid filtration combustion to describe chemical reactions in the gas phase and heterogeneous reactions on the surface of particles in the layer of a catalyst. This work considers a mathematical model for the synthesis of porous materials from a granular low- calorie gas-free powder mixture, the reaction of which is supported by the filtration combustion of a gas mixture. The dynamics of synthesis is described by the equations as follows: the heat balance in the condensed and gas phases, the motion of the gas phase, the rate of reactions in phases, the conservation of momentum with additional relations. Numerical study was carried out using finite-difference methods. Mechanisms and modes are determined for the propagation of reaction fronts in phases, depending on the characteristics of gas flow during coflowing and counter filtration, the ratio of the gas-phase and solid-phase reaction constants, and the parameters of interphase heat transfer.

References

1. A.G. Merzhanov, I.P. Borovinskaya, Yu.E. Volodin. Combustion mechanism of porous metal samples in nitrogen, Dokl. AN SSSR. - 1972. V. 206. No.4. - P. 905 - 908. 2. A.P. Aldushin, A.G. Merzhanov. Propagation of thermal waves in heterogeneous media. Novosibirsk: Nauka, 1988. 3. K. Hiaro, Y. Miyamoto, M. Koizumi. Synthesis of siliconnitride by a combustionreaction under high nitrogen pressure// J. Ceram. Soc. – 1986. V. 69. – №4. – P. 60 – 61. 4. M.Toledo, C. Rosales, C. Silvestre, S. Caro. Numerical simulation of the hybrid filtration combustion of biomass // Int. J. Hydrogen Energy. – 2016. V. 41. – P. 21131 –21139. 5. M.Toledo, E. Vergara, A. Saveliev. Syngas production in hybrid filtration combustion // Int. J. Hydrogen Energy. – 2011. V. 36. – P. 3907 –3912. 6. А. P. Gerasev. Hybrid autowaves in filtration combustion of gases in a catalytic fixed bed // Combust., Expl. Shock Waves. – 2008. – V. 44. – № 2. pp. 123-132.

598 ______Combustion waves: theory and experiment FEATURES OF ACOUSTIC EMISSION DURING SHS PROCESSES

R.M. GABBASOV, A.I. KIRDYASHKIN, V.G. SALAMATOV 10/4 Akademichesky Ave., Tomsk, 634055, Russia, [email protected], 79528875560

Acoustic emission (AE) is the generation of acoustic waves due to the internal structure rearrangement of a substance. The AE investigation is a tool for direct diagnostics and the obtaining of valuable information on the kinetics and mechanics of various fast processes used in engineering, chemistry and other fields. This effect takes place during the mechanical deformation and fracture of solids, the transformation and phase transitions of substances, as well as during the combustion of fuels with the formation of gaseous products [1-4]. In the latter case, the AE is called a "singing flame". Acoustic emission was recorded in the works [5, 6] during the propagation of a reaction wave in condensed media. However, this effect has been studied insufficiently so far. Considering the importance of these processes for pyrotechnics and combustion synthesis of materials, the present work is devoted to the investigation of this effect for various condensed systems. Combustion was studied using the powder mixtures Ni + 31.5wt.%Al, Zr + 19.1wt.%B, FeO + 60wt.%Al and the Ni-Al laminate system consisted of Ni and Al twisted wires with the component ratio of Ni + (28-30)wt.%Al. The studies have shown that the signal of acoustic emission occurs at the moment of ignition and damps after the completion of combustion (fig. 1, a). Emission occurs both in the form of weakly repeated discrete pulses with a frequency from 50 Hz to 52 kHz (fig. 1, b) and ordered high-frequency self-oscillations from 850 kHz to 1.10 MHz (fig. 1, c).

a b c Fig. 1. AE signal during the combustion of the Ni+31.5wt.%Al mixture (a), structure of discrete pulses (b), structure of ordered high- frequency self-oscillations (c). Analysis of the data obtained shows that the most probable source of AE is mechanical pulsations of systems caused by a local change in the density of a condensed medium during chemical and phase transformations, as well as by the mechanical stress with a sharp temperature change and the development of microcracks (discrete pulses). Ordered high-frequency self-oscillations are likely to be caused by the resonance of dynamic parameters during chemical (phase) transformations of a condensed substance and by standing acoustic wave in the reaction zone. REFERENCES [1] O. Kanji // Journal Acoustic Emission. –2011. – 29. 284–308. [2] V.I. Ivanov, G.A. Bigus, and I.E. Vlasov // Acoustic Emission. – Izd. Dom Spektrum, Moscow, 2011. [3] V.V. Afanas'ev, S.A. Abrukov, N.I. Kidin, A.K. Kuz'min // Combustion, Explosion, and Shock Waves. – 1995. – 4. 432–436. [4] K.K. Ahuja, J. Lepicovsky, R.H. Burrin // AIAA Journal. – 1982. – 12. 1700–1706. [5] A.I. Kirdyashkin, R.M. Gabbassov, Yu.M. Maksimov, V.G. Salamatov // Combustion, Explosion, and Shock Waves. – 2013. – 6. 1–6. [6] E.G. Klimchuk, A.L. Parakhonsky // Zel'dovich Memorial: Accomplishments in the combustion science in the last decade Borisov A.A., Frolov S.M. 3rd International Conference. – 2015. 186–190.

599 ______Combustion waves: theory and experiment INVESTIGATION OF MINIMUM LASER IGNITION ENERGIES OF COMBUSTIBLE GAS MIXTURES1

Y.V. ANISHCHANKA*, E.Y. LOKTIONOV*, V.D. TELEKH* *Bauman Moscow State Technical University, 5-1 2nd Baumanskaya str., Moscow, 105005, Russia, [email protected],+74992636299

Demonstration of a compact 'laser plug' [1] accelerated research in the field of combustible gases optical ignition to evaluate optimum impact parameters. Laser ignition takes place due to gas optical breakdown followed by plasma and shock wave formation, those lead to deflagration core onset (detonation and autocatalytic reaction are also possible) [2]. Laser breakdown threshold (unlike electric) in gases decreases with pressure increase up to 10s of MPa [3], so smaller ignition energy is needed at higher compression. Minimum ignition energy (MIE) values for electric spark have been calculated and experimentally evaluated long ago, but for laser ignition significantly higher values were found, as explained, due to shorter duration and smaller size of the laser impact region [4]. MIE is known to be strongly dependent on mixture equivalence ratio φ and pressure. For electric spark ignition is has been shown, that MIE dependency on φ has a pronounced minimum that moves towards richer mixture with fuel molecular weight increase. Existing data confirm this tendency for laser ignition also. The feature of electric breakdown ignition is high energy input rate in the discharge channel. For laser ignition, energy input rate depends on gas spectral absorption. So only a percent of incident laser energy may be deposited in laser spark near breakdown threshold. However, at combined laser impact, significant threshold decrease can be reached [5]. It is worth mentioning, that MIE for certain gas mixture contents and pressure is expected to be independent on the way of energy deposition. MIE is strongly dependent on air-to-fuel ratio and pressure, and is virtually independent on laser pulse length, at least in pico- to microsecond range [6]. There is a mess in published data on laser ignition energies, because authors often do not state whether incident or deposited energy is mentioned; experimental conditions features, such as laser focusing [7], gas velocity and temperature [8] are often not described properly. To resolve these discrepancies, minimum pulse energy (MPE) term is suggested for laser impact, and is a more practical one. Although MPE is easy to measure, its value depends a lot on experimental conditions, which are not always properly documented. So the best way to compare MPE’s for different fuel mixtures is to perform experimental series at the same conditions. And this was the aim of our work. Minimum laser pulse energies for ignition – MPE – have been experimentally evaluated for hydrogen, methane, propane and butane based fuel mixtures of different equivalence ratios (φ~0.5–2) and pressures (p~0.5–6 bar) at the impact of 1064 nm, 532 nm, 355 nm, 266 nm, 213 nm radiation of nanosecond (~12 ns) Nd:YAG laser. Experimental setup was similar to described in [9]. Obtained values are compared to MIE and laser breakdown thresholds at the same conditions. MPE, as expected, decreases significantly with pressure increase, same as gas optical breakdown threshold does. Minimum of MPE(φ) dependency drifts towards richer mixture, but at the same time, curve meander broadens making ignition less sensitive to pulse energy in a wider range of equivalence ratios. To evaluate efficiency of laser ignition we suggest to use MPE to breakdown threshold ratio. The obtained results are of great importance for laser ignition systems development. REFERENCES [1] N. Pavel, et al. // Opt. Express. – 2011. – V. 19. – №. 10. P. 9378-9384. [2] T. X. Phuoc // Handbook of Combustion. - Wiley-VCH Verlag GmbH. 2010. [3] E. Y. Loktionov, et al. // Journal of Applied Spectroscopy. – 2015. – V. 82. – №. 4. P. 607-613. [4] T. X. Phuoc, and F. P. White // Combustion and Flame. – 1999. – V. 119. – №. 3. P. 203-216. [5] E. Y. Loktionov, et al. // Journal of Physics: Conference Series. – 2016. – V. 774. – №. P. 012125. [6] P. D. Ronney // Optical Engineering. – 1994. – V. 33. – №. 2. P. 510-521. [7] D. K. Srivastava, et al. // Optics and Lasers in Engineering. – 2014. – V. 58. – №. P. 67-79. [8] J. Griffiths, et al. // Optics and Lasers in Engineering. – 2015. – V. 66. – №. P. 132-137. [9] E. Loktionov, et al. // Journal of Physics: Conference Series. – 2017. – V. 927. – №. 1. P. 012030.

1 This work has been performed using ‘Beam-M’ research facility and was supported by the Russian Ministry of Education and Science (task No. 13.6918.2017/8.9).

600 ______Combustion waves: theory and experiment EXHAUST COMPOSITION AT LASER IGNITION IN A 2-STROKE AND WANKEL ENGINES 1

Y.V. ANISHCHANKA*, E.Y. LOKTIONOV*, N.A. PASECHNIKOV* *Bauman Moscow State Technical University, 5-1 2nd Baumanskaya str., Moscow, 105005, Russia, [email protected],+74992636299

Compact piston engines are considered as an alternative for fuel elements and batteries for portable, automotive and UAV. Those are characterized by small combustion chamber comparable to spark plug inter- electrode gap in axial direction, and its low ratio to bore size. For Wankel engines this problem exists at any scale though. Multi-point ignition could be helpful, but is too complicated in electric spark way. To increase engines specific capacity, higher compression is needed. Unlike electric spark, laser ignition energy decreases with pressure increase in reasonable range up to ca. 100 bar. However, of piston engines, data regarding four- strokes only could be found [1], but those are not so compact as two-stroke and rotary (Wankel) ones. For the latter, laser ignition was only suggested by Mazda in 2011, but there are still no papers regarding this problem, except constitutive patent application [2]. The former, to the best of our knowledge, have been considered for the first time only recently, being fed by LPG [3]. Albeit two-stroke and Wankel engines have higher volume and mass specific power, comparatively simple construction and easy handing, those are now outweighed by high fuel consumption and harmful emissions rates. Since combustion is to be induced at every rotation unlike 4-srokes, this increases thermal load. Laser ignition of lean fuel mixtures in such engines could significantly improve performance by reduced fuel consumption and cleaner exhaust. Lower combustion temperatures also reduce thermal stabilization issues, which are more pronounced in compact systems. One more feature needed for portable and temporarily set engines is ability to use multiple and locally available low-quality fuels. E.g., in remote Arctic areas natural gas is available from the ground, but gasoline and diesel are brought from industrial centers, which can increase operating costs by an order of magnitude. Modern ecology standards for internal combustion engines leave a very small niche for high specific performance, but not so clean exhaust two-stroke and rotary engines. The former could be switched to gas feeding comparatively easily, but the latter has ignition and starting issues even with optimized fuels. Laser ignition could resolve these problems. So the aim of this work was to measure exhaust composition of laser ignited two-stroke and Wankel engines fed by different fuels. We have used a custom-built laser spark plug (2.7 mJ, 0.5 ns at 1064 nm) to ignite hydrogen, methane, propane and butane fuel mixtures in model two-stroke and Wankel engines and measured exhaust composition with an industrial gas analyzer. Experimental setup is described in [3]. NOx emission for stoichiometric C3Hx/C4Hx 81% / 16% based mixture combustion was 16 ppm and 6 ppm for idling two-stoke and Wankel engines, respectively. So poor ecological performance characteristic for two-stroke and Wankel engines could be fixed with laser ignition. REFERENCES [1] I. Javed, et al. // Laser Physics. – 2016. – V. 26. – №. 7. P. 076001. [2] T. Takezaki, et al. // Journal of Physics: Conference Series. – 2016. – V. 717. – №. 1. P. 012083. [3] E. Y. Loktionov, et al. // Journal of Physics: Conference Series. – 2018. – V. 946. – №. P. 012066.

1 This work has been performed using ‘Beam-M’ research facility and was supported by the grant of the President of Russia (No. 14.Z56.18.633- MK).

601 ______Combustion waves: theory and experiment TEMPERATURE HYSTERESIS IN THE UNSTABLE COMBUSTION MODE OF SHS: EXPERIMENT WITH HIGH-SPEED MICRO-PYROMETRY1

GULYAEV P.Y. Yugra State University

The aim of this study is to report a new experimental regularity of the change in the propagation velocity of SHS as a function of the adiabatic temperature at the local point of the combustion front. The paper presents the results of measuring the temperature and velocity during the propagation of the combustion wave, obtained using a special television micro-pyrometer (1200 x 800 pixels) with high spatial (5.85 µm / pixel) and resolution time (1 ms/frame). A high accuracy of temperature measurement was provided by the use of a new method of spectrally-bright pyrometry (Patent RUS 2616937) from 800 to 2000oC, with an error less than 1%. In this work, the technique of carrying out the experiment and statistical data on the nonlinear correlation of velocity and temperature are shown. In the process of self-propagating high-temperature synthesis of oxide bronzes KxTiO2 , the phenomenon of thermal hysteresis of the velocity of the combustion wave from the synthesis temperature was observed by the method.

1 The reported study was funded by RFBR according to the research project No. 18-08-01475.

602 ______Combustion waves: theory and experiment

MODIFICATION OF THE STRUCTURE AND PROPERTIES OF METAL

AFTER PULSE FORMATION MODE1

YU. N. SARAEV, V. P.BEZBORODOV

Institute of strength physics and materials science SB RAS, Tomsk

The study of the influence of the modes of surfacing coatings electrodes brand LB-52U DC and pulsed its change on the structure and properties of these coatings. Surfacing was carried out with the help of an experimental research complex consisting of inverter power supply FEB-315 "MAGMA" and parameters recorder AWR-224 MD with a personal computer. Used plate with dimensions 100×50×6 mm the mode Parameters of welding electrodes LB-52U DC and pulsed measurements of energy parameters given in tables 1 and 2. Table 1 DC mode parameters

Layer I, А U, В Vсв, m/h the Level of heat input, kJ/m

Root 90 25 4,9 1405

Facing 150 25 6,99 1642

Table 2 The parameters of the pulse mode

Layer Ii, A IР A ti, s tP, s U, В Vсв, m/h the Level of heat input, kJ/m

Root 90 40 0,3 0,3 20 4,29 1017

Facing 180 50 0,3 0,3 24 6 1606

The microstructure of the base metal is a pearlite and ferrite which corresponds to the average grain size of ≈ 4.7 µm. A mild rolling strokefest perlite. The volume fraction of pearlite is ≈ 20 %. The average hardness of 1450 MPa.In surfaced coatings made by pulsed arc surfacing, the metal structure is more homogeneous and dispersed. The microhardness of the metal formed at a constant current was 1860 MPa, which is about 10 % lower than the pulse mode.

Summary

1. The structure of the metal formed on the pulse mode, more dispersed and homogeneous than performed on DC; 2. Metal root layer after the pulse is due to the grinding, the higher microhardness - ⁓ 10 %.

1The work was carried out within the framework of the basic research Programs of the state academies of Sciences for 2013-2020, project III.23.2.1.

603 ______Combustion waves: theory and experiment IMPROVING THE PROPERTIES AND RELIABITY OF OPERATION OF METAL STRUCTURES AT LOW CLIMATIC TEMPERATURES USING METHODS OF COMPLEX MODIFICATION OF PROTECTIVE COATINGS1

YU. N. SARAEV ⃰ , V. P. BEZBORODOV ⃰, M. B. PEROVSKAY ⃰, K. A. BOLGARU ⃰ ⃰⃰⃰ , B. S BRAVERMAN⃰ ⃰,

⃰ Institute of strength physics and materials science SB RAS, Academichesky Avenue, 2/4, Russia, Tomsk, 634055, phone: 8(3822)286850

⃰⃰ ⃰ Tomsk scientific center SB RAS, Akademicheskii Pr. 10/4, , Tomsk, Russia,634055

The main way to improve the performance properties (wear and corrosion resistance) of products is surfacing coatings. Modern methods of surfacing, allow to regulate the speed of cooling of the surfacing zone, to control the processes of melting, crystallization and formation of the metal structure and, accordingly, its physical and mechanical properties. In this regard, an important task is to study the influence of technological modes of surfacing on the physical, mechanical and operational properties of the surfaced coatings of structural steels in order to increase their use of new filler materials modifying the melt, and pulsed energy, reducing the structural heterogeneity of the metal. The aim of this work is the study of structure, physico-mechanical and service properties of deposited coatings using pulsed methods of welding with modification of molten metal composite powder materials with submicrocrystalline structure. Samples from deposited compounds of steel 09G2S were investigated. surfacing was carried out by composite electrodes power source FEB-315 "MAGMA" with a remote "Pulse" to implement the pulse-arc process. Registration of parameters of the surfacing process was carried out using the device AWR-224 MD. This paper presents a comprehensive approach to improve the properties of deposited coatings using the method of modification of materials by compounds of carbide and nitride of titanium with submicrocrystalline structure in the pulsed mode of welding. The influence of modification by dispersed particles and electric arc influence on the structure, physical-mechanical and operational properties of coatings is studied. It is established that modification by refractory compounds with submicrocrystalline structure allows to increase dispersion of structure and hardness of coatings. It is shown that the application of the pulsed-arc surfacing method with the modification of the molten metal by a composite powder material of carbide and chromium nitride and titanium with submicrocrystalline structures allows these hardening phases to be stored in the molten coating. Modification of coating compounds of carbide and nitride of chromium and titanium with submicrocrystalline structure in the pulsed mode of welding allows to increase the homogeneity of the structure of the deposited coating increases its hardness and durability. The structure of the coating metal made by pulsed-arc surfacing does not contain a significant amount of extended dendrites in contrast to constant current surfacing. The use of surfacing electrodes T590 and EN-60M low-carbon steel 09G2S pulsed arc technology allows the formation of coatings with a fine- grained structure compared to those obtained at direct current. It is experimentally confirmed that the use of new surfacing materials modified powders with submicrocrystalline structure under pulsed conditions surfacing coatings increases the performance of products operating at low climatic temperatures.

______1This work was supported out within the framework of the basic research Programs of the state academies of Sciences for 2013-2020, project III.23.2.1.

604 ______Combustion waves: theory and experiment COMBUSTION SYNTHESIS OF MACROPOROUS β+γ’-NIAL ALLOYS1

V. KITLER, A. MAZNOY, N. PICHUGIN Tomsk Scientific Center SB RAS, 10/4 Akademicheskii pr., Tomsk, 634055, Russia, [email protected], +79234124765

Intermetallic alloys have emerged with enormous potential for use in components for a wide variety of high-temperature industrial applications. The objective of this study is to determine the conditions for combustion synthesis of macroporous Ni-Al alloys with an ordered crystal structure β-NiAl+γ’Ni3Al. Combustion synthesis was carried out on laboratory samples obtained by vibroforming of the reaction mixture Ni+Al (particle size of 5-100 micron, Al concentration 13-30 wt.%) in cylindrical mould (diameter 20-40 mm, height 40-80 mm). It has been found that without using any additives, the synthesized materials are characterized with microporous and cracks structure (fig 1, a). To obtain macroporous materials without structure defects CaO and CaCO3 additives were used. The additives are capable to melt or decompose in the combustion wave zone, which provides two effects. Firstly, the chemical composition of additives should act as a flux for the destruction of the oxide layers on the surface of reagents and activate the capillary interaction of the melts. Secondly, the generated gas must loosen a layer of the reaction mixture. This allows creating a thermal gap between the combustion zone and the heating zone. This approach allows one to realize an oscillatory combustion mode and obtaining the high-permeability alloys (fig 1, b,c). The XRD patterns showed cubic B2 β-NiAl and L10 γ’Ni3Al as the major structures of the synthesized materials o (fig 1, d). The minor amounts of the L60 Ni3Al were also revealed, which annealed after 1000 C one hour treatment. Electron microscopy also revealed only B2 and L10 phases in annealed materials (fig 1, e). a b c

0 3 mm 5 mm 10 mm Pores After anealing e β-NiAl d Combustion Ni3Al tet synthesized γ'-Ni3Al

β-NiAl After anealing γ'-Ni3Al

30 40 50 60 70 80 90 100 110 0 30 μm 50 μm 100 μm

Fig. 1. Porous structures (a-c), X-ray patterns (d) and SEM image (e) of combustion synthesized Ni-Al macroporous materials.

1 This work was carried out within the state task of FASO (No. 0365-2018-0002)

605 ______Combustion waves: theory and experiment MEASUREMENTS OF EMISSIONS FOR LPG COMBUSTION WITHIN A POROUS CYLINDRICAL BURNERS 1

N. PICHUGIN, A. MAZNOY Tomsk Scientific Center SB RAS, 10/4 Akademicheskii pr., Tomsk, 634055, Russia, [email protected], +79234124765

This study has been motivated by the experimental research findings on temperature and radiative characteristics of cylindrical Ni-Al alloy burners operated in the internal combustion mode [1] that reveal a significant improvement in the radiation efficiency. It can be expected that in this combustion mode the flue gases will be characterized by low CO/NOX concentrations. A cylindrical or spherical axis-symmetrical configuration provides natural stabilization of the combustion front inside the porous burner due to a decrease in the filtration speed with the radius growth. Therefore, the size of the burner pore channels can be optimized for low CO/NOX emissions. The objective of this study is to experimentally study the effects of burner pores structure on environmental characteristics for LPG combustion. The cylindrical burners with equal overall porosity of 55% but different structure parameters have been studied: the average size of the frame elements is 600, 1000 and 1350 μm respectively. The burners are made in the form of hollow cylinders with a hemispherical head, the diameter of 48 mm, total length of 76 mm, and the wall thickness of 8.5 mm [1]. The LPG of the following composition has been used as a fuel: methane 10.67 vol.%, ethane 13.82 vol.%, propane 61.66 vol.%, the rest (carbon dioxide, butane, pentane) – 13.83 vol.%; the low heat value is Hi = 80.60 kJ/nl. Three firing rates were analyzed FR = 160, 260 and 420 kW/m2. The cylindrical burner were fixed in a housing equipped with a flow distributor. The Polar gas analyzer equipped with a BOP-1 dehydration unit (Promekopribor, Russia) was used to measure the concentration of CO/NOX in the flue gases. In order to avoid a premix of air to the combustion products, the burner was placed inside a quartz tube with a diameter of 90 mm and a length of 500 mm. It has been found that the porous structure of the burner significantly determines CO emission: the larger are the structural elements of the material, the lower is CO concentration in the flue gases (fig 1, a-c). It has been also established that as the firing rate increases, the CO emission decreases. Thus, at air-fuel equivalence ratio α ≈ 1.2, the CO concentration decreases from 50-100 ppm at 160 kW/m2 to 5-10 ppm at 420 kW/m2. It has been established that with a decrease in the equivalence ratio, the NOX concentration in the combustion products is significantly reduced, while the NOX emission is practically independent of the firing rate and porous structure of the burner. As shown in Fig.1d, at α ≈ 1.1 the NOX concentration is about 40 ppm, at α > 1.3 NOX < 20 ppm is provided. Thus, the obtained results testify to the relevance of studied burners for the development of environmentally friendly heat engineering equipment.

400 a 100 b 20 c 60 d

160 kW/m2 260 kW/m2 420 kW/m2 2

2 300 6000 m 75 15 O

O 1000 m 40

% % % %

1350 m 0 0

200 50 10 &

& & ppm

ppm 20

, , , ,

100 25 5 X

CO NO

0 0 0 0 1.0 1.1 1.2 1.3 1.4 1.0 1.1 1.2 1.3 1.4 1.0 1.1 1.2 1.3 1.4 1.0 1.1 1.2 1.3 1.4 Equivalence ratio Equivalence ratio Fig. 1. Experimental dependences of CO (a-c) and NOX (d) concentration on air-fuel equivalence ratio

REFERENCES [1] Fursenko R., Maznoy A., Odintsov E., Kirdyashkin A., Minaev S., Sudarshan K. // International Journal of Heat and Mass Transfer.  2016.  98.  277-284.

1 This work was carried out within the state task of FASO (No. 0365-2018-0002)

606 ______Functional materials and coatings

WIRE FEED ELECTRON BEAM ADDITIVE MANUFACTURING OF METALLIC COMPONENTS

S.V. FORTUNA, A.V. FILIPPOV, S.Yu. TARASOV, E.A. KOLUBAEV Institute of Strength Physics and Materials Science of Siberian Branch Russian Academy of Sciences, 2/4, pr. Akademicheskii, Tomsk, 634055, Russia, e-mail: [email protected], ph.: 8(3822)286863

Fast development of additive manufacturing is a global challenge in modern technology development, which determines provisions for developing and using new advanced, high-production and competing processes. This work has been focused on developing an electron multibeam additive directed energy wire deposition process and commercial high-production robotic equipment for manufacturing large metallic components. This process involves a layer-by-layer deposition of metal by electron beam melting of wire and obtaining then a near-net-shape component. The advantage of this process is its high deposition rate up to 12 kg/h which is unachievable with other additive processes [1]. Also it allows making large up to 5000 mm size fully dense and structurally homogeneous components from both refractory and heat-resistant alloys [2]. Extra feature of this process is a feasibility of simultaneous deposition of dissimilar metals and thus forming a composite structure inside a vacuum chamber [3]. Therefore, it excludes any oxidizing of the component. The project implementation allows filling a commercial niche both in home and abroad markets of equipment and materials needed for high-production additive manufacturing of large complex shape components. Achieving such a goal will provide our technological leadership in high-production electron beam additive manufacturing. The purpose of this work is the development of laboratory 3D-printing equipment and chooses the technological mode of samples producing from stainless steel 321 grade. To examine the macro-and microstructures of the material produced under various conditions of 3D printing, structural studies of cylindrical samples in a cross section were performed by optical microscopy methods. In order to determine the gradient of mechanical properties and the manufacturing quality of thin- wall (<3.5 mm) axisymmetric cylindrical and conical bodies, mechanical compression tests were carried out. In this paper, a set of laboratory equipment for wire feed electron beam additive manufacturing of metallic components has been developed. Optimal process parameters have been found and used for manufacturing axisymmetric samples from the SS 321 wire. The structure and mechanical properties of the samples have been studied. The compression strength of sample No. 3 was the highest and even higher than that of base SS 321. Samples No. 1 and No. 3 had clearly seen fusion interfaces between the successively deposited beads. For a more homogeneous specimen No. 2 in the macrostructure, a high anisotropy of the conditional yield point was observed. Sample No. 1 had high anisotropy of mechanical properties both in the directions of growth and deposition. It was established that varying the additive process parameters such as wire feed rate, substrate rotation rate one may obtain finally printed components of various microstructure and mechanical characteristics. Manufacturing components with their mechanical characteristics either higher or close to those of base cast metal is also feasible. Moreover, it becomes possible to obtain microstructures of either high or zero anisotropy.

The work was financially supported by the Russian Federation via the Ministry of Education and Science of the Russian Federation (Agreement No. 14.610.21.0013, project identifier RFMEFI61017X0013).

References

1 Ding, D., Pan, Z., Cuiuri, D. et al. Wire-feed additive manufacturing of metal components: technologies, developments and future interests Int J Adv Manuf Technol 81.1, 465 (2015). 2 Lewandowski, J.J. Seifi, M. Metal Additive Manufacturing: A Review of Mechanical Properties, Annual Review of Materials Research 46, 151 (2016). 3 Wang, J. Tang, H. Review on metals additively manufactured by SEBM, Materials Technology 31,2, 86 (2016).

607 ______Functional materials and coatings

MICROSTRUCTURE AND PROPERTIES OF TI-6.5AL-3.5MO-1.5ZR-0.3SI PARTS PRODUCED BY ELECTRON BEAM MELTING

N.S. PUSHILINA*, E.B.KASHKAROV**, M.S.SYRTANOV**, V.N. KUDIIAROV**, R.S. LAPTEV**, M. GUSTOMYASSOV**, Y.KUSHNAREV**, V.V. FEDOROV** * National Research Tomsk Polytechnic University, Lenina Avenue 30, Tomsk, 634050, Russia, [email protected],89609789855 * * National Research Tomsk Polytechnic University, Lenina Avenue 30, Tomsk, 634050, Russia

Nowadays additive manufacturing (AM) are being actively implemented in many industries. The advantages of AM such as a high rate of production and the possibility of creating unique product geometry over traditional manufacturing methods of metal products are undeniable. The use of additive manufacturing allows creating a new generation of materials with a unique set of properties. One of the most actual methods of creating three-dimensional products is the method of "electron beam melting" - EBM [1-2]. This method has the following advantages: high possible resolution in the horizontal plane, high performance, this method does not require subsequent heat treatment to achieve high strength. The wide range of various defects, anisotropic structures and etc. are formed during the process of products synthesis from titanium alloys with the help of additive technologies due to the high cooling rate of the material. The formation of the structural- phase state of the samples occurs as the result of powder melting to the temperature of 1900 °C and subsequent rapid cooling to a the temperature of ~ 700 °C followed by cooling to the room temperature. Structure and properties of manufactured alloy parts depend on many factors, such as powder composition, part thickness, beam current, beam speed, scanning strategy (including line offset), energy input, etc. Thus, the regularities of structure formation and evolution depending on the additive manufacturing parameters have a great practical importance. The aim of this work is to study the influence of manufacturing conditions on the evolution of the structural-phase state and the change in the mechanical properties of samples prepared by electron beam melting from Ti-6.5Al-3.5Mo-1.5Zr-0.3Si powder. The samples have been manufactured on an experimental unit developed and manufactured at the R&D Laboratory for Modern Production Technologies in the National Research Tomsk Polytechnic University. To study the beam current effects on the build parts, samples were fabricated at different beam current (3-6 mA). The hatching direction was rotated by 90° between each layer. The investigations were carried out using X-ray diffractometer, optical and scanning electron microscopy, the method of measuring microhardness and Young's modulus. The patterns of structure and properties change of samples made by electron beam melting from Ti-6.5Al- 3.5Mo-1.5Zr-0.3Si powder have been established, depending on the manufacturing conditions.

This material is based upon the work supported by Russian Science Foundation, research project No. 17-79-20100. REFERENCES [1] L.E. Murr // Addit. Manuf.  2015.  5.  № . 40–53. [2] L.E. Murr, S.M. Gaytan, D.A. Ramirez, E. Martinez, J. Hernandez, K.N. Amato, et al. // J. Mater. Sci. Technol.  2012.  28.  № . 1–14.

608 ______Functional materials and coatings

EXPERIMENT ON CYLINDRICAL NI-AL RADIANT BURNER WITH HEAT RECUPERATION1

A. MAZNOY, A. KIRDYASHKIN, N. PICHUGIN, A. GUSCHIN. Tomsk Scientific Center SB RAS, 10/4 Akademicheskii pr., Tomsk, 634055, Russia, [email protected], +79234124765

For generating infrared fluxes gas-fired radiant burners are widely used. Currently, radiant burners are successfully used for heating industrial zones, as well as for drying and thermal processing of materials. This study has been motivated by the experimental findings on temperature and radiative characteristics of cylindrical burners from Ni-Al alloy [1] that reveal a signiﬁcant improvement in the radiation efficiency of burners operated in the internal combustion mode. Here, the flame stabilizes in the internal cavity of the cylindrical burner that allows achieving a radiation efficiency of about 60%. A further increase in radiation efficiency is possible owing to preheating of the fuel-air mixture. Therefore, the objective of this study is to investigate the effects of heat recuperation on radiation characteristics of cylindrical burners. To create cylindrical burner, an intermetallic Ni-Al alloy is used, which is characterized by high oxidation resistance and high-temperature strength. The burner are made by the combustion synthesis in the form of hollow cylinders with a hemispherical head, the diameter of 48 mm, total length of 77 mm, and the wall thickness of 8.5 mm. Porosity is 55%, the average size of the frame elements is 1000 μm. The burner was installed inside a conical hollow-type recuperator made from an aluminum alloy (fig. 1). The natural gas with the Hi = 35,62 kJ/nl has been used as a fuel. The composition of the fuel-air mixture was controlled by precision flow controllers (Eltochpribor, Russia). The radiation efficiency was measured with using a 12A P/N 7Z02638 sensor (Ophir, Israel) in accordance with the procedure described in [1]. Following modes of operation have been applied: air-fuel ratio in the range of 1.1 - 1.46, firing rate 100 - 320 kW/m2. For each experimental point, the measurements were repeated three times and the resulting data were calculated for confidence level 95%. The findings have suggested that heat recuperation is an effective method of enhancement of the radiation efficiency (see the table).

Heat insulating Preheated air filling CH4 supply supply Flame arrester Air supply Al reflector & recuperator

Porous burner Fig. 1. Scheme of the experimental burner with heat recuperation

Firing rate [kW/m2] Air-fuel ratio Rad. Eff. [%] Rad. Eff. [%] Fixed air-fuel ratio α = 1.10 Fixed firing rate 100 kW/m2 100 65.9 ± 1.0 1.10 65.9 ± 1.0 160 67.3 ± 1.6 1.28 63.9 ± 1.0 220 63.5 ± 2.3 280 61.5 ± 0.7 1.46 61.9 ± 0.9 340 58.8 ± 4.1

REFERENCES [1] Fursenko R, Maznoy A, Odintsov E, Kirdyashkin A, Minaev S, Sudarshan K. // International Journal of Heat and Mass Transfer.  2016.  98.  277-284.

1 This work was carried out within the state task of FASO (No. 0365-2018-0002)

609 ______Functional materials and coatings

PREPARATION OF NANOLAMINATES IN THE TI-CR-AL-C SYSTEM BY THE SHS METHOD

SHULPEKOV AM, LEPAKOVA OK, SALAMATOV VG, AFANASYEV NI Tomsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Akademichesky Ave. 10/4, Tomsk, 634055, Russia [email protected], +7(3822)492294

The peculiarities of the structure of the crystal lattices of nanolaminates cause a unique combination of the properties of both metals and ceramics: high electrical and thermal conductivity, easily processed by cutting, crack resistance, resistant to high temperature oxidation and thermal shocks, elasticity at high temperatures, excellent corrosion resistance in aggressive liquid media and at the same time low density, high elasticity, are stable at temperatures above 1000 °C. Materials based on the MAX phases of the Ti-Cr- Al-C system are promising for use in machinery operating under extreme operating conditions, such as electrical contacts, bearings, heating elements, heat exchangers, as high-temperature ceramics [1]. The aim of the work is to obtain materials based on the Ti-Cr-Al-C system by the SHS method, to study the physicochemical properties of materials and the mechanism of phase and structure formation. The data of high-speed video recording showed that burning of powder mixtures, with a chromium content of more than 30% and a relative density of 0.86, occurs in a non-stationary mode. After ignition, a flat decaying reaction wave propagates from the beginning of the sample with a velocity monotonically decreasing along its axis from 6.5 mm / s to zero for 0.04 s. (fig. 1)Then, in the low-temperature zone of the wave (T = 1380 K, according to the data of dynamic spectrometry) reaction foci originate and begin to move across the sample, which initiate the next damped wave. The speed of distribution of the foci is 12.9 mm / s, their temperature is 1860 K.

1600 2000

1400 1800

1200 1600

1000 1400

800 1200 600

Temperature, K 1000 Temperature, K 400 800 200 600 0 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 time, sec time, sec Fig. 1 The sample thermogram. Measurement: a) using a thermocouple, b) using dynamic spectrometry.

a) b) Fig. 2 a) Diffraction pattern of the sample. I) stoichiometry of Ti2AlC, II) Ti1.9Cr 0.1AlC, III) Ti1.5Cr0.5AlC. Phases: 1 - Ti2AlC, 2 - Ti3AlC2, 3 - TiC. b) Microstructure of the samples.

Metallographic studies and X-ray phase analysis revealed phases of Ti2AlC, Ti3AlC2, Cr2AlC, TiC. The phase composition of the samples depends on the ratio of the components. Formulations with high plasticity and heat resistance were found (fig. 2). Materials are promising for use as heat-resistant structural materials.

REFERENCES [1] Zhimou Liua, Erdong Wua, Jiemin Wanga and all // Acta Materialia. – 2014. – 73. 186–193.

610 ______Functional materials and coatings

DIFFUSION INDUCED RECRYSTALLIZATION OF NI3AL-BASED ALLOYS

N.I. AFANASYEV, О.K. LEPAKOVA Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294

Ni3Al-based alloys exhibit an abnormal temperature dependence of yield stress and high heat resistance, which allow us to consider these alloys to be promising heat-resistant materials. To increase the creep resistance, the intermetallide Ni3Al was doped with chromium and carbon. The evolution of the phase composition and substructure during diffusion induced recrystallization (DIR) was studied using a micro-analyzer (Camebax microbeam), and the Neofot-21 optical and JEM-F200 electron microscopes. After SH-synthesis and annealing at 1473 K for 4 hours, the alloy has an aggregate structure consisting of equiaxial Ni3Al grains with a size of ∼50 μm and Сr7С3 particles with a volume fraction of ∼1.6% located along the large-angle grain boundaries (Fig. 1a). The small-angle boundaries are free of particles. Annealing at 1573 K leads to the dissolution of carbides and the development of DIR. DIR forms a structure (Fig. 1b, c) that is morphologically similar to the structure of supersaturated solid solutions after cellular decay. In contrast to ordinary cellular decay, the increased concentration of the doping element (chromium) is observed in the regions undergoing the transformation, not in the initial matrix. A structure consisting of γ′ phase cubic-shaped grains 0.2-0.3 μm in size is formed in cells. Thin layers of the disordered γ phase are observed in cells (Fig. 1c). The initial grain boundaries do not move during the growth of cells. The reaction front has a diffuse dislocation structure (Fig. 1c), which indicates a high voltage in the reaction front.

Fig. 1. Structure of the Ni3Al alloy in the initial state (a) and after DIR (b, c).

Dispersion of Ni3Al grains near the boundary area is caused by the saturation of matrix with chromium, which leads to a decrease in the temperature during the disordering of intermetallides. Figure 2 shows the creep curves of the alloy. δ , % 1

6 2

0 10 30 90 150 210 270 330 450 630 750 870 1030 1410 τ , мин

Fig. 2. Creep curves of the Ni3Al alloy at 1473 K in the initial state (1) and after DIR (2).

DIR leads to a sharp decrease in the creep resistance of the alloy (Fig. 2).

611 ______Functional materials and coatings

SYNTHESIS OF METAL-CERAMIC COMPOSITES BASED ON SILICON NITRIDE IN THE COMBUSTION MODE AND CATALYTIC ACTIVITY1

А.А. REGER, К.А. BOLGARY Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634055, Russia, [email protected], +7(3822)492294

At present, heterogeneous photocatalysis and the high oxidizing capability of hydroxyl radicals are successfully used to remove soluble organic substances [1]. Ozonizing and UV radiation in the presence of oxygen-containing catalysts and reagents contribute to the formation of OH radicals. The ferrioxalate system and photo-Fenton are photoactive in homogeneous catalysis. The results showed that iron-containing composites based on boron, silicon and sialon nitrides exhibited high catalytic activity under UV radiation during the degradation of oxalic acid, phenols, formaldehyde, and colouring agents [2]. The catalytic activity of materials was found to be caused by the presence of iron in the composition of 2+ matrix and the formation of photoactive systems such as the photo-Fenton (Fe /H2O2/UV), ferrioxalate 3- (Fe(C2O4)3 /UV) and ferricomplexonate (FeEDTA/UV) systems in the solution by adding reagents (activators, Н2О2, Н2С2О4, EDTA). The results also showed that the photoactivity of metal-ceramic composites during the degradation of soluble organic substances depends on the optical properties of matrix that contains semiconductor compounds. To obtain a material based on silicon nitride, titanium and sialon, metallic titanium was added to the green mixture (aluminum ferrosilicon) in the amount of 5-40 wt.%. The phase composition of combustion products depends essentially on the amount of titanium. Figure 1 shows the X-ray diffraction patterns of the synthesized samples.

а b

3 1

1 1 2 2 2 2 2 1 5 4 3

2 5 4 4 2 5 5 2 5 5 5 4 2 4 2 5 2 4 2 1

30 35 40 45 50 55 30 35 40 45 50 55 2 2

Fig.1. X-ray diffraction patterns of aluminum ferrosilicon+15%Ti(a) and aluminum ferrosilicon+20%Ti(b) (1-TiN, 2 -β- Si3N4, 3-Fe, 4 – FeSi, 5 - α- Si3N4) The catalytic activity of synthesized composites (samples (a) and (b)) was evaluated during the degradation of colouring agents (methylene blue, eosin). The results have shown that the greatest degradation of methylene blue is observed in the presence of Н2С2О4 (ferrioxalate system) and reaches 67-73 wt.%. When eosin is disintegrated, a high activity is exhibited by the composite а with an additive of EDTA (ferricomplexonate system). In addition, an increase in the concentration of EDTA by an order of magnitude (2∙10–4–2∙10–3 M) leads to the increase in the oxidation degree of eosin by more than 2 times (from 35 to 85wt.%). Thus, iron-containing metal-ceramic composites based on silicon and titanium nitrides are promising for purification of waste water from colouring agents, using UV radiation.

REFERENCES

1. Oppenlander T. // WILEY VCH Verlag, 2003. 368 p. 2. Skvortsova L.N., Chuklomina L.N., Mokrousov G.M., Batalova V.N., Wu J.J. // Russian J. Appl. Chemistry. 2012. V. 85. No. 1. P. 2021-2025.

1 This work was supported by FASO (No. 0365-2018-0002) and partially by RFBR (project No. 16-03- 00635 a)

612 ______Functional materials and coatings EFFECT OF SHUNGITE ADDITIVES ON THE NITRIDING OF SILICON IN THE COMBUSTION MODE A.A. AKULINKIN, K.A. BOLGARU Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], +7(3822)492294

At present, ceramic materials, modified with silicon carbide, are of special interest due to the capability of silicon carbide to successfully act as a catalyst carrier [1]. One of the promising methods for the obtaining of nitrides and carbides is the self-separating high-temperature synthesis (SHS) method that is characterized by high productivity and low energy consumption, which is very important for industrial production. The purpose of this work is to investigate the effect of shungite additives on the phase composition of products obtained by the combustion of silicon in nitrogen. Silicon (grade kr-0) and shungite (Zazhoginskoe field) were used as green mixtures. Samples were burned in a constant-pressure furnace by the method described in [2]. The experiments have shown that the combustion of silicon in nitrogen occurs in a nonstationary mode, and the final product contains a sufficient amount of unreacted silicon in addition to α- and β-Si3N4. To increase the efficiency of silicon nitride based materials, it is of interest to add carbon-containing compounds. For this purpose, shungite was added to a green mixture consisting of silicon. The amount of shungite in the green mixture was varied in the range of 0-40%. A significant amount of carbon in shungite can lead to the formation of carbides. The samples were synthesized according to the procedure described in [3].

N % V,mm/s 35 1,0 1 0,9 30 2 0,8 25 0,7

20 0,6 0,5

15 0,4 no combustion no 10 0,3 0,2 5 0,1 0 0,0 0 10 20 30 40 shungite wt. % Fig. - Nitrogen content in products (1) and combustion rate (2) versus the amount of shungite (nitrogen pressure is 4 MPa) As studies have shown, the increase in the amount of shungite by more than 10 wt.% during the nitriding of silicon results in the change of the nonstationary combustion mode to the stationary one, and the combustion product is a homogeneous material. In the case, when the amount of added shungite was more than 40 wt.%, the combustion of silicon was not observed. Increasing the amount of shungite, the propagation velocity of combustion wave initially increases insignificantly and then drops sharply. In addition, the amount of nitrogen absorbed decreases noticeably with an increase in the amount of shungite in the range of 20-40% (Fig.). On the one hand, an increase in the amount of an inert additive reduces the combustion temperature, as evidenced by the thermograms of the process. The decrease in the combustion temperature is due to the fact that during the nitriding the total reacting mass increases, and the inert additive does not contribute to the heat release. On the other hand, the adding of schungite influences on the filtration of nitrogen in the green mixture. The increase in the amount of shungite slows the sintering of material, which increases the gas permeability of the sample. Thus, the studies conducted have demonstrated the nitriding of silicon with shungite in the combustion mode. When the amount of shungite added to the green mixture was 20%, we obtained a densely sintered doping nitrogen-containing material with a maximum nitrogen content of 24.8%. When the amount of shungite was 40%, we obtained a loose unsintered powder material that can be used to obtain ceramic materials by known compaction methods. The nitriding process was investigated, and the stable conditions were found for initiating the process. The phase composition of combustion products was determined. REFERENCES 1. H. Wang, R. Schmack, B. Paul, M. Albrecht, S. Sokolov, S. Rummler, E.V. Kondratenko, R. Kraehnert. - Appl. Cata. A Gen. - 537 (2017) pp. 33-39. 2. Merzhanov A.G., Borovinskaya I.P. Self-propagating high-temperature synthesis of refractory inorganic compounds // Dokl. AN SSSR. - 1972. - V. 204. -No.2. - P. 366-369. 3. Chuhlomina L.N., Bolgaru K.A., Avramchik A.N. // Refractories and Industrial Ceramics. - 2013. -No.- 1-2.- P. 15-19.

613 ______Functional materials and coatings

SYNTHESIS OF MANGANESE-DOPED MESOPOROUS SILICA NANOPOWDER FOR TARGETED DRUG DELIVERY1

O. A. ZLYGOSTEVA*, S. Yu. SOKOVNIN*, **, V.G. IL’VES** * Ural Federal University Named after the First President of Russia B. N. Yeltsin, Mira 19, Yekaterinburg, 620002, Russia, [email protected], +79122917153 ** Institute of Electrophysics Ural Branch of the Russian Academy of Sciences (RAS), Amundsen 106, Yekaterinburg, 620016, Russia

It is well known that conventional drugs have many disadvantages, such as poor solubility, unexpected biodistribution during the therapeutic process and a number of side effects. In recent years, the studies of nanopowder (NP) for targeted drug delivery are rapidly developing, because NP can improve many pharmacological properties of conventional drugs [1]. Protection of the drugs by NP, which can easily enter cells in targeted tissues, increases intracellular concentration of the drugs. This can reduce the quantity of drug needed to attain the particular concentration in the place of interest, and drug concentration at non- target locations in the organism. Mesoporous silica NP is of significant interest for development of delivery systems due to its good general biocompatibility, high specific surface areas, pore size and opportunity to surface functionalization [2]. The manganese dopant can promote visualization of delivery process using MRI. The researched manganese-doped mesoporous silica NP (SiO2-MnO2) with 0.1, 3, 5 % dopant concentrations have been produced by the method of electron beam evaporation in low-pressure gas (4 Pa) on NANOBIM-2 installation. The target was made of silica NP (Aerosil 90) and manganese dioxide powder (GOST 4470-79). NP was deposited on large-surface glass noncooled substrates in the powder collection chamber to prevent the crystallizer material from being absorbed into the NP [3]. According to BET analysis, produced SiO2-MnO2 NP are highly porous with high pore volume (average size and pore volume of 22.6 nm and 0.76 cm3 /g, respectively, the specific surface area increases with the increasing in dopant concentration from 75.78 to 176.35 m2 /g). Transmission microscopy of NP demonstrates porous agglomerates of NP, with a disordered hollow structure. The NP with such hollow structure must be particularly noteworthy in drug delivery systems because they also can efficiently accommodate drugs into the hollow interiors [1]. Cytotoxicity experiments on cells showed that NP exerted low toxicity. For loading experiments anti-inflammatory drug Amoxicillin and chemotherapy drug Doxorubicin was chosen. The loading was achieved by soaking the NP in a solution of the drug to allow adsorption interactions between the drug and the particle surface. These interactions usually involve hydrogen bonding and electrostatic attractions [4]. After sonication the NP suspension was stirring during 24 h. The loaded NP was separated by centrifugation (10 000 rpm, 10 min) and washed once with water. The supernatant and NP were collected. The release of drug from NP was determined by suspending of loaded NP in deionized water. The loading degree of drug was determined by spectroscopy. Thus, produced SiO2-MnO2 mesoporous NP is a perspective material for pharmaceutical applications especially for the targeted drug delivery systems.

REFERENCES [1] Y. Li, N. Li, Z. Pan et al. // ACS Appl. Mater. Interfaces. – 2017. – 9. - 2123−2129. [2] Y. Hu, L. Ke, H. Chen et al // International Journal of Nanomedicine. – 2017. – 12. - 8411–8426. [3] S. Yu. Sokovnin, V. Il'ves // Ferroelectrics. – 2012. - 436. - 101-107. [4] Cicily J. Ronhovde // PhD (Doctor of Philosophy) thesis. - 2017. – 125.

1 This work was performed within a support of the Russian Science Foundation project No 16-16-04038.

614 ______Functional materials and coatings

STRUCTURE AND WEAR RESISTANCE OF SHS TiC+HSS COMPOSITE COATINGS, OBTAINED BY ELECTRON BEAM FACING1

A.V. BARANOVSKIY*, G.A. PRIBYTKOV**, M.G. KRINITCYN*, I.A. FIRSINA** * Tomsk Polytechnic University, 30 Lenin av., 634050, Tomsk, Russia, tel. +79991782742, e-mail: [email protected] ** Institute of Strength Physics and Materials Science of the Siberian Branch of the Russian Academy of Sciences, 2/4, pr. Akademicheskii, 634055, Tomsk, Russia High-speed steels (HSS) are widely used as a binder in titanium carbide metal matrix composites. The most familiar are carbide-steels that made by sintering of titanium carbide and steel powder mixtures. [1]. Carbide-steels composed of titanium carbide particles uniformly distributed in a steel matrix and have much higher hardness and wear resistance as compared with rolled steels. To get similar structure in wear resistant coatings produced by cladding or sputtering titanium carbide and steel powder mixtures are commonly used. To avoid segregation in the powder mixtures it is reasonable to use composite powders, which constitute granules composed of disperse hard particles in metal matrix. Self-propagating high temperature synthesis (SHS) should be recognized to be the most cost-effective and high-performance preparation method of composite powders with carbide hardening phase [2]. The structure of TiC+Fe composite powders with wide C/Ti ratio were discussed in [3]. The effectiveness of electron beam facing (EBF) in wear resistant coating applications is confirmed by authors [4]. The microstructure, hardness and wear resistance of EBF coatings, cladded by «TiC-HSS steel binder» composite powders obtained by wave combustion mode SHS method have been studied in our work. Evolution of microstructure of the composite powder granules during the surfacing is described. The evolution consists of partial dissolution of the granules in the molten pool and subsequent crystallization of the dispersed carbide phase in dendrites from a liquid metal solution containing titanium and carbon. The heat-affected zones are observed and the hardness gradient of coating-surface areas is examined. The connection between microstructure of the coatings and their hardness and abrasive wear resistance is presented. Relations between HSS binder content in the SHS powder, hardness and abrasive wear rate (fig 1) are discussed.

a b Fig. 1. Relations between HSS binder content in the SHS powder, hardness (a) and abrasive wear rate (b) of the EBF coatings. 1 – 125-200µ, 2 – 200-315µ.

REFERENCES [1] A Y.G. Gurevich, V.K. Narva, N.V. Fraga, Karbidostali, Metallurgia, Moscow, 1988. [2] A.S. Rogachev, A.S. Mukasyan, Combustion for the synthesis of materials, Fizmatlit, Moscow, 2013. [3] A. Saidi, A. Crysanthou, and J.V. Wood, Preparation of Fe-TiC composites by the thermal explosion mode of combusion synthesis, Ceramic Int. 23 (1997) 185-189. [4] Pribytkov G.A., Khramogin M.N., Durakov V.G., Korzhova V.V. Pokrytiya, poluchen-nyye elektronno-luchevoy naplavkoy kompozitsionnymi poroshkami karbid titana – svyazka iz bystrorezhushchey stali R6M5. Svarochnoye proizvodstvo. 2007, №8, s. 14-17.

1 This work was carried out in the framework of the fundamental scientific investigations program of the state academies (project No. 23.2.2) under financial support of Russian foundation of basic research (grants Nos. 16-08-00493 and 16-48-700381)

615 ______Functional materials and coatings STRUCTURE EVOLUTION DURING ELECTRON BEAM MELTING OF TITANIUM – TITANIUM CARBIDE COMPOSITE POWDERS1 M.G. KRINITCYN1,2, G.A. PRIBYTKOV1, A.V. BARANOVSKIY 1 Institute of Strength Physics and Materials Science SB RAS, Tomsk, 2/4, pr. Akademicheskii, Tomsk, 634055, Russia [email protected] 2Tomsk Polytechnic University, Tomsk, Lenina str., 30, 634050

Composite powders with a calculated (in the assumption of the formation of titanium carbide of the equiatomic composition) with a content of a titanium bond of 30 to 60 volume % were obtained by layer-by- layer burning in argon medium of cylindrical compacts of powder mixtures of titanium (<160 μm) and carbon black (P-803). SHS powders were diluted with titanium powder to an integrated titanium content of 80% by volume in the coating in order to optimize melting process. The powder mixtures were melted on the substrates of titanium alloy on a special installation that includes a vacuum chamber with a pumping system, a powder dosimeter with a dosage control device, a manipulator and an electron gun with a high-voltage power supply and an electronic beam control system. The structure and morphology of powders obtained by SHS method, as well as the structure and mechanical properties of surfacing with these powders were studied. It was demonstrated that the structure of surfacing is inherited from the powder (Fig. 1). The structure of the coating formed by the electron beam surfacing of SHS composite powders "titanium carbide - titanium binder" is determined, first of all, by the degree of development of the recrystallization of the carbide phase in the melt of the surfacing bath. When surfacing with a mixture of large initial carbides of non-stoichiometric composition, the deposited coating has a structure with a bimodal distribution of the carbide phase represented by the initial carbides and recrystallized carbides of an order of magnitude smaller than the original ones. When surfacing with a mixture containing a composite powder with a fine carbide phase, a more significant recrystallization occurs. With the appropriate selection of the technological mode of surfacing, it is possible to preserve the carbide inclusions of the fusion composite powder and, thus, the purposeful adjustment of the coating structure, namely the dispersion of the hardening carbide phase. The hardness and abrasive wear resistance of electron beam coatings deposited by SHS with composite powders "titanium carbide-titanium" are determined by structural characteristics, in particular - by the density (absence of internal porosity) of carbide inclusions in the titanium matrix and their dispersion. The main mechanism of abrasive wear of the deposited coatings is the wear of the intercarbide interlayers of the titanium bond, followed by the ejection of carbide inclusions with a weakened bond to the matrix. Electron beam surfacing of coatings with composite powders "titanium carbide - titanium" provides an increase in hardness by 3.7 (2.2) times in comparison with titanium VT1-0 (alloy VT6), and abrasion resistance in 21.6 (13.8 ) times, respectively.

a b Fig. 1. Microstructure of the “TiC + 60 vol.% Ti” powder (a) and electron beam coating with this powder (b)

1 This work was funded by Russian Scientific Foundation (project No. 17-19-01425).

616 ______Functional materials and coatings

MECHANOCHEMICAL SYNTHESIS OF HIGHDISPERSED COPPER POWDERS T.A. UDALOVA* ,**, E. T. DEVYATKINA*, S. V. VOSMERIKOV* , T. F. GRIGOREVA*, N. Z. LYAKHOV* *Institute of Solid State Chemistry and Mechanochemistry of Siberian Branch of Russian Academy of Sciences, 18 Kutateladze str., Novosibirsk, 630128, Russia, [email protected], 8-952-922-56-45 **Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russia

Ultra-disperse metal powders are used in the formation of materials with increased porosity (battery electrodes, fuel cells, filters and adsorbents), with a fine-grained structure, with increased mechanical properties; when modifying the properties of polymer matrices (increase in strength, wear resistance, microhardness), the growth of films with a small grain size, the creation of 3D printer pastes, as components of solid phase synthesis, for highly disperse systems with a liquid medium. The reactions of reducing copper oxides or metal salts with magnesium are highly exothermic [1]. Thesis investigation is devoted to mechanochemical synthesis of ultradisperse copper powders by the reduction of their oxides by magnesium, with the separation obtained copper powders from mechanocomposites. In the process of mechanical activation of solid mixtures, simultaneously with the grinding of substances, an increase of the contact surface, acceleration of mass transfer, and, as a consequence, the activation of their chemical (mechanochemical) interaction. Applied importance of the studies of mechanochemical reduction of metal oxides for the purpose of opening and processing a diverse number of mineral and technogenic raw materials is difficult to overestimate, since this method is quite environmentally friendly. In the case of using as an active metal - magnesium, it is necessary to know the compounds that can form at different stages of the process of mechanical activation in copper oxide -magnesium systems. The mechanochemical reduction of copper (I and II) oxides by magnesium in order to obtain copper powders is associated with the search for optimal conditions for mechanical activation, ensuring the oxidation-reduction reaction proceeds with the formation of copper and separation of its copper from by-products [2], determination of their shape dimensions, and oxidation protection conditions. It should be noted that treatment with hydrochloric acid solution allows partial transfer of Cu2O into the solution in the presence of air oxygen, to form a highly soluble CuCl2. To separate the finely dispersed copper powder from the reduction by-products (magnesium oxide, copper oxide (I)), two variants of acid treatment for 30 min are proposed: 1) 1M HCl (343 K); 2) 0.5 M H2SO4 (298 K) followed by washing with distilled water and acetone. However, copper is separated from Cu2O under standard conditions, when 1M hydrochloric acid is treated, or 0.5 M sulfuric acid, followed by water rinsing is not possible. In the presence of air oxygen, at temperatures of 298 and 343 K, on the diffractograms, except for the reflexes of copper, Cu2O reflexes are retained. To remove the copper oxide (I) and stabilize the copper powder from oxidation after washing with water, additional treatment with a stabilizer solution, water and acetone was introduced. Diffractograms of ultradisperse copper powders after such treatment do not change when samples are stored under standard conditions for at least 3 months. Mechanochemical reduction of copper (I and II) oxides by magnesium was studied by X-ray phase analysis, electron microscopy, and element analysis of energy-dispersive x-ray spectroscopy. The conditions for separation of copper particles from other products and copper protection from oxidation during storage are determined. The results of electron-microscopic investigations have shown that after separation from by- products and stabilize copper powders consist of aggregates of primary particles of almost spherical form with dimensions of about 100 nm, which are part of the secondary particles - aggregates of 0.2 to 2 microns. The method of energy-dispersive x-ray spectroscopy is shown that the powders Mg copper content does not exceed 2%.

References [1] Munir Z., Anselmi – Tamburini V. // Mater. Sci. Rep. 1989. V. 3. P. 277-365. [2] Raschman P., Fedoro¢ková A. “Study of inhibiting effect of acid concentration on the dissolution rate of magnesium oxide during the leaching of dead-burned magnesite” Hydrometallurgy, (2004). V. 71, P. 403-412.

The work was carried out within the framework of the state assignment of the IHTTM SB RAS (project 0301- 2017-0021).

617 ______Functional materials and coatings

ULTRAFINE SILICON AND GERMANIUM FROM MECHANOCOMPOSITES SI(GE)/MGO AFTER THE SEPARATION OF MAGNESIUM OXIDE T.A. UDALOVA* ,**, S. V. VOSMERIKOV*, E. T. DEVYATKINA*, T. F. GRIGOREVA*, N. Z. LYAKHOV* *Institute of Solid State Chemistry and Mechanochemistry of Siberian Branch of Russian Academy of Sciences, 18 Kutateladze str., Novosibirsk, 630128, Russia, [email protected], 8-952-922-56-45 **Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russia

The specific properties of substances in the ultradisperse state open great opportunities for the development and creation of new materials with increased porosity, sensory systems, modified polymeric matrices and etc. [1]. Highly dispersed silicon under standard conditions, it is only able to interact with the strongest oxidant - fluorine. High light-absorbing capacity is several times higher than that of the crystalline form. In the form of powder, it is easy to apply to any surface, whether plastic or glass. Therefore, ultrafine silicon is so convenient for use. This is one of the most sought-after elements in electronics and engineering. The possibilities of its application are expanding every year. Ultra-disperse germanium powders are used in the coating of optical components, as a doping additive, in the creation of new composite materials, certain germanium alloys (Au-Ge, Cu-Ge, etc.), nanotechnologies, microelectronics, microwave devices, fiber and infrared optics, nuclear physics (gamma- ray detectors), and also for the production of germanium single crystals. The thermodynamic possibility of reactions of magnesium and oxides silicon and germanium reactions was determined based on literature data. The physico-chemical properties of silicon, germanium, magnesium, magnesium oxide (melting points, redox potentials, etc.), which prevent significant sintering of mechanochemical reduction products, make it possible to form a Si(Ge)/MgO mechanocomposites. Magnesium oxide, when reacted with hydrochloric acid, forms a highly soluble compound MgCl2 [2], therefore, it can be extracted quite easily from Si(Ge)/MgO mechanocomposites. Due to the fact that the reduced silicon and germanium does not interact with the solution of dilute hydrochloric acid, with acid treatment of the mechanocomposite, it is possible to separate silicon and germanium from the by-products of mechanochemical reduction. The effect of the stoichiometric composition and the time of mechanical activation on the composition of the products of mechanochemical reduction of SiO2 or GeO2 by magnesium by X-ray phase analysis were studied. It is shown that the process of mechanochemical reduction is completed by 4 min of activation. The conditions for separating silicon and germanium from mechanocomposites are determined. Electron microscopic analysis showed, that ultra disperse silicon and germanium powders consist of aggregates of primary particles, almost spherical in shape with sizes from 50 to 100 nm (Fig. 1). The energy-dispersive X- ray spectroscopy (EDS) method was used to determine the magnesium content in the obtained of silicon and germanium powders.

a b Fig. 1. Electron micrographspurified ultradisperse silicon (a) and germanium (b), magnification: a – 50000; b– 20000. REFERENCES [1] Gusev A.I. Nanomaterials, nanostructures, nanotechnologies: monograph / A.I. Gusev. - M.: publishing house FIZMATLIT, 2009. - 416 p. [2] Raschman P., Fedoro¢ková A. “Study of inhibiting effect of acid concentration on the dissolution rate of magnesium oxide during the leaching of dead-burned magnesite” Hydrometallurgy, (2004). V. 71, P. 403-412.

The work was carried out within the framework of the state assignment of the IHTTM SB RAS (project 0301- 2018-0001).

618 ______Functional materials and coatings

Ga2O3 – A NEW PROSPECTIVE MATERAL FOR THz DOMAIN

D.M. EZHOV*, V.A. SVETLICHNYI*,**, Y.M. ANDREEV*,*** *Tomsk State University, 1 Novosobornaya Sq., Tomsk, 634050, Russia, [email protected], +7 3822-531-591 **Institute of High-Current Electronics SB RAS, 2/3 Akademicheskii Ave., Tomsk, 634055, Russia ***Institute of Monitoring of Climatic and Ecological Systems SB RAS, 10/3 Academicheskii Ave., Tomsk, 634055, Russia

Gallium oxide (Ga2O3) is known as transparent semiconducting material existing as five (α, β, γ, δ, and ε) polymorphs. Obtaining a crack-free, and high structural and optical quality single crystal Ga2O3 is difficult due to enhanced decomposition of Ga2O3 and the melt/vapor interaction with the crucible. At high temperatures (>900 °C) only β-phase, with a melting point of from 1820 ˚C to 1900 ˚C, is stable. β-Ga2O3, having a monoclinic system, belongs to the C2/m group symmetry class of materials that can be grown from the melt. As a semiconductor, it shows outstanding physical properties: hardness, thermal and chemical stability and therefor widely used in electronics. No application in optics were reported [1]. In this work, we studied its optical properties in the entire transparency range; in the THz domain, it was studied for the first time. In fact, there is strong depending of optical properties on the growth technology. To produce the β-Ga2O3 powder hydrothermal technique was used. Ga was put in hot (∼ 60 °С) water for three 30-minite cycles. Formed GaO(OH)×H2O hydroxide was extracted from the water and dried at 60-80 °С. It chemical formula and type of structure were confirmed by XRD, Raman and IR spectroscopy. It was shown that compound belong to orthorhombic Pnma space group (denoted as Ga-60), it was also confirmed by TEM, that shows that powder consist of micron and submicron orthorhombic particles. After drying, mixture was annealed at 600, 900 and 1100 °С (denoted as Ga-600, Ga-900 and Ga-1100). Ga-900 and Ga-1100 are found to be pure β-Ga2O3 in comparison with Ga-600, which contains both: trigonal R-3m and monoclinic С2/m phases (Fig. 1b). It is necessary to note, that annealing changes structure of the initial mixture and leads to enlarging and agglomerating of powder into sub-micron structures with monoclinic symmetry that can be clearly seen at Fig. 1a.

Fig. 1. (a) SEM-photo of Ga-1100 powder; (b) X-ray powder diffraction spectra; (c) VIS-IR absorption spectra. Main transparency window is found to be from 0.280 µm (Fig. 1c) to 12.5 µm. In order to study THz properties of tested materials, THz spectrometer with time resolution (THz TDS) was used. During the measurements, powders of selected samples were placed in 1 mm thick polyethylene cell. Measured results were compared with those from the study of samples grown by chemical vapor transport technique that well matches each other. β-Ga2O3 shown attractive anisotropy of refractive index (up to 0.22) and small, down to -1 2–3 cm , absorption coefficient at room temperature. So, β-Ga2O3 is likely to be very attractive material for fabrication different optical parts for the THz domain. REFERENCES [1] Z. Galazka, R. Uecker, D. Klimm, K. Irmscher, M. Naumann, M. Pietsch, A. Kwasniewski // ECS Journal of Solid State Science and Technology. − 2017. − Volume 6. − № 2. – P. 3007-3011.

619 ______Functional materials and coatings

RECENT ADVANCE IN THE DEVELOPMENT OF MATERIALS FOR EXTREME ENVIRONMENTAL APPLICATIONS

N.I. BAKLANOVA *Institute of Solid State Chemistry and Mechanochemistry, Kutateladze st., Novosibirsk, 630128, Russia, [email protected]

Progress in aerospace is related to the development and modernization of propulsion systems capable of operating under extreme environmental. At present, there are several concepts to protect the structures from degradation at temperatures above 2000°C. The developed concepts are based on (i) the ability of some systems to "self-healing" (Hf(Zr)B2-SiC systems) [1]; (ii) usage of so-called high-entropy ceramics, i.e. an equimolar mixture of five or more refractory carbides, nitrides or borides, effectively preventing diffusion of oxygen inwards the material; (iii) usage of the materials that have an exceptionally low recession rate in oxygen, such as multilayered iridium coatings. However, these concepts have disadvantages. Therefore, the proposed materials can not provide the stable operation of structures at temperatures above 2000°C, either because of uncontrolled heating, or insufficient strength, as well as the complexity of composition control. Thus, there is an urgent necessary to develop new approaches to protect the structural materials under extreme conditions. Several approaches proposed by us to the synthesis of ultra-high temperature materials as bulk or coatings, as well as their ablation resistance at ultra-high temperatures will be discussed. The first approach is based on the multilayered coating concept and involves the deposition of refractory carbides combined with noble metals. To obtain carbides of refractory metals of IV-V groups the reactive chemical vapor deposition (RCVD) was used. The results of the thermodynamic modeling of several systems “refractory metal-C-F” in wide temperature and pressure ranges will be presented. Analysis of the calculated molecular composition of the vapor phase in equilibrium with solids showed that the chemical transport of refractory metal through the gas phase is mediated by lower metal fluorides. Using RCVD method, the tantalum, hafnium and some other refractory metal coatings and bulk materials were obtained. The complex carbide- iridium coatings on carbon supports were also obtained by RCVD and MOCVD methods, respectively [2]. The results on the morphology, phase and elemental composition, as well as the response of the systems on the exposure to extreme temperatures and aggressive gas flow will be presented. The second approach to design of materials that can resist to extreme environmental conditions is based on the usage of iridium-containing compounds - iridides of refractory metals - as the base elements of such coatings. It was shown that the iridide-based materials display excellent ablation resistance under arc-jet testing at temperatures higher than 2000°C. The special benefits of the new designed materials result from their relative oxygen impermeability and special microstructure similar to superalloys.

REFERENCES [1] Ultra-High Temperature Ceramics. Materials for Extreme Environment Applications //Ed. W. Fahrenholz et al. − Wiley, 2014. [2] V.V. Lozanov, N.I. Baklanova, N.B. Morozova // Journal of Structural Chemistry - 2015 − V.56 − № 5. P.900-906.

620 ______Functional materials and coatings

SINTERING AND OXIDATION OF MB2-SiC (M = Hf, Zr) CERAMICS WITH ADDITION OF Cr

A. UTKIN1, D. BANNYKH1, 2, N. BAKLANOVA1 1Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze st., Novosibirsk, 6300128, Russia, [email protected], +7(383)233-24-10 2Novosibirsk State University, 1 Pirogova st., Novosibirsk, 630090, Russia

Transition metal borides, carbides, and nitrides are gaining increased attention as refractory compounds with superior properties at very high temperatures. Hafnium and zirconium diborides especially combined with ~20 vol% of silicon carbide display a number of unique properties such as hardness, high thermal conductivity and chemical stability. Due to a high melting points of HfB2 and ZrB2 (3380 and 3245°C, respectively) the fabrication of dense and durable HfB2 or ZrB2-based ceramics needs in the special high- temperature sintering techniques, such as hot pressing (HP) or spark plasma sintering (SPS). The typical temperature of sintering of such ceramics that gives a relative density of 98% or higher is about 2000- 2200°C for HP and 1900-2000°C for SPS. Alternative approach to compact the ceramic powders is based on the formation of transient liquid- phase (TLP) during thermal treatment of ceramic powders with some aids. It is known that silicon carbide reacts with chromium at 1600°C with the formation of liquid Cr-Si-C eutectics. One can propose that the transient liquid phase could promote the sintering of MB2-SiC (M = Hf, Zr) ceramics at temperatures lower than 2000°C. The other benefit to use chromium as sintering additive is in the fact that the oxidation of the MB2-SiC-Cr system at high temperatures could lead to the formation of protective layer due to the formation of the MO2-Cr2O3 (M = Hf, Zr) eutectics at temperatures higher than 1900°C. Thus, the present work aims to the study of the effect of chromium additive on the densification behavior, chemical transformations and oxidation resistance of the HfB2-SiC and ZrB2-SiC ceramics. It was shown that increase of Cr content from 0 to 15.5% leads to the continuous growth of its relative density of HfB2-SiC ceramics from 64 to 90%. It was stated that the formation of transient liquid phase Cr- Si-C-B occur at 1600°C and this liquid phase promotes the intense sintering of MB2 (M = Hf, Zr) and SiC powders. The decrease in the porosity of ceramic samples leads to increase in their oxidation resistance at 1000-1500°C due to the change of the oxidation mechanism from bulk to passive. The results obtained in this work shows that the chromium can be considered as a promising sintering additive for the HfB 2-SiC and ZrB2-SiC systems as well as other SiC-based ceramics due to the rather low sintering temperature (1600°C).

Fig. 1. Relative density of HfB2-SiC ceramics (left) and its mass gain during oxidation (right) in dependence of Cr content.

621 ______Functional materials and coatings

DEVELOPMENT OF A COMPOSITE CORROSION-RESISTANT MATERIAL BASED ON TITANIUM FOR VESSELS OF CHEMICAL INDUSTRIES 1

M.G. GOLKOVSKI*, V.V. SAMOYLENKO**, I.A. POLYAKOV**, V.A. BATAEV**, I.K. CHAKIN*. * Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, 11, Academician Lavrentiev Avenue, Novosibirsk, 630090, Russia, [email protected], phone: +7(383)3294250 ** Novosibirsk State Technical University, 20, K. Marx Prospekt, Novosibirsk, 630073, Russia

Titanium and its alloys cause an increased interest of researchers, since they advantageously combine high strength, plasticity and corrosion resistance. This makes it possible to manufacture from this material the critical parts that operate at chemical, petrochemical and nuclear industries. However, in some cases, the corrosion resistance of titanium is insufficient and the metal is actively destroyed by the action of strong acids heated to the boiling point. One of the most rational solutions to increase the corrosion resistance of titanium products under similar conditions is their surface alloying with tantalum, niobium and zirconium. This solution provides a comprehensive approach, since it allows reducing the dissolution intensity of the surface of the protected material, to retain high mechanical properties of the substrate and to save the more expensive alloying elements (Ta, Nb, Zr). As a method of depositing protective layers, the authors propose a technology for electron beam surfacing in the air atmosphere. The method possesses a high productivity, while it lacks the main drawback inherent in most electron beam facilities - the need for using a vacuum chamber. Electron-beam surface alloying of the of billets is realized on the industrial electron accelerator ELV-6 that is produced by the Budker Institute of Nuclear Physics of the Siberian Branch of Russian Academy of Science. The design features of the accelerator outlet device allow the output of a beam with high energy of electrons directly into the air atmosphere. Before processing, the powders of alloying elements and flux are applied to the surface of the protected material. Subsequent reflow by an electron beam results in a two-layer material consisting of a coating of about 2 mm thickness and a titanium substrate with a thickness of at least 8 mm. An essential feature of the method is the ability to subject the described material to such technological operations as welding, bending and rolling for necking. In the composite material, because of rolling or the thermal action of the welding arc, cracks, delaminations and other defects do not occur. Reducing the thickness of the material during the rolling operation can reach 80%. A prototype of a corrosion-resistant reactor was manufactured from surface-alloyed flat blanks by using the technological operation of welding. It was tested using boiling concentrated nitric acid as an aggressive medium for 15 days. The test results showed that the corrosion resistance of the reactor walls coincides with the resistance of individual samples cut from the coatings after surfacing, and is about 20 μm / year. Thus, it is possible to recommend the technology of electron beam surfacing in the air atmosphere to produce vessels and tanks of enhanced corrosion resistance, in which strong acids are heated.

REFERENCES (STYLE “EFRE2018 TITLE REFERENCES”) [1] Golkovski M. G. et al. // Materials Science & Engineering A.  2013.  578. 310-317. [2] Bataev V.A et al. // Applied Surface Science.  2018.  437. 181-189.

1 This work was supported by Russian Ministry of Education and Science. Unique ID of the applied research (project): RFMEFI60414X0135

622 ______Functional materials and coatings

AN INVESTIGATION OF SHS PRODUCTS IN TITANIUM, CARBON (BLACK CARBON) AND ALUMINUM POWDER MIXTURES 1

G.A. PRIBYTKOV*, A.V. BARANOVSKIY**, V.V. KORZHOVA*, M.G KRINITCYN**

*Institute of Strength Physics and Materials Science, Akademicheskii pr., 2/4, Tomsk, 634055, Russia, e-mail: [email protected] **National Research Tomsk Polytechnic University, Lenin pr.,30, Tomsk, 634050, Russia

Titanium carbide is the only phase in SHS product in titanium and carbon powder mixtures of equiatomic proportion. At the SHS in the mixtures containing titanium excess along with titanium carbide of non-stoichiometric composition there is a free titanium in the SHS products presenting metal-matrix composite consisted of carbide particles imbedded into titanium matrix (binder) [1]. It is interesting to investigate SHS regularities in three-component Ti-C-Al powder mixtures. An additional aluminum dopant complicates a picture of powder components interaction strongly because of double compounds formation ability. Double compounds in Ti-C-Al system are titanium aluminides and Al4C3 aluminum carbide. Besides, it is possible three component compounds formation having MAX of phases structure [2]. We studied a structure and phase composition of SHS products in Ti-C-Al powder mixtures, containing 10, 20, 30 and 40 mass % aluminum. Ti to C atomic ratio in the mixtures was constant and equals 1. Reaction mixtures were prepared from titanium (ТПП-8, 99,5 %, <160 µm.), black carbon (П-803, 300 nm. average particles size) and aluminum (ПА-4, 98 %, <100 µm.) powder mixtures. Ø 20 × 25 mm cylindrical samples were pressed from the mixtures to 35 % porosity. The combustion was initiated by heating of an igniting pellet by molybdenum wire coil. A resultant porous cakes were crashed and sieved to <125 microns granules of composite powders. The powders were investigated be X-ray diffraction (DRON-7 Burevestnik diffractometer, Russia), optical metallography (AXIOVERT-200MAT, Zeiss, Germany) and scanning electron microscopy (EVO 50, Zeiss, Germany). According to X-ray diffraction data the basic phases in SHS products of all investigated compositions are titanium carbide and aluminum (tabl. 1). A small amount of Al3Ti is present in the SHS products.

Table1. Phase composition of the SHS products Reactive mixtures composition A relative content of the particular phases, % TiC Al Al3Ti Ti+C+10 mass. %Al 83 12 5 Ti+C+20 mass. %Al 80 15 5 Ti+C+30 mass. %Al 58 33 9 Ti+C+40 mass. %Al 58 38 4

According to scanning electron microscopy (SEM) the carbide inclusions size in the SHS composite powders depends on aluminum content in the reaction mixtures and decreases monotonously from 4,3 to 1,0 µm. while aluminum content rises from 10 to 40 mass. %. Carbide size dependence of thermally inert additives in the reaction mixtures is typical [3]. The reason is the burning temperature fall by inert additives which are not involved in exothermic reaction. The synthesized and investigated composite powders will be used for cladding and sputtering of the coatings and for printing 3D samples and products by of selective laser fusion technology.

REFERENCES [1] G. Pribytkov, M. Krinitcyn, V. Korzhova // Advanced materials. – 2016. – No. 5. – 59-68. (Russ). [2] A.Hendaoui, D. Vrel, A.Amara, P. Langlois, M. Andasmas, M. Guerioune // Journ. Eur. Ceram. Soc. 2010. – 30. – 1049-1057. [3] Rogachev A.S., Mukasian A.S. // Combustion for materials synthesis.-Moscow. Fizmatlit Publ. 2013. (Russ)

1 This work was supported by Russian Scientific Foundation

623 ______Functional materials and coatings

SHS OF TiC – NiCrBSi BINDER COMPOSITE POWDERS1

G.A. PRIBYTKOV*, I.A. FIRSINA*, V.V. KORTHOVA*, M.G KRINITCIN**

Iron and nickel base water or nitrogen sprayed powders are widely used for sputtering and cladding of wear resistant coatings. NiCrBSi powders are the most often used. High hardness and wear resistance of the coatings are provided by disperse particles of refractory compounds (borides, carbides and silicides) uniformly distributed in the metal matrix. However insufficient hardness and eagle-like shape of the inclusions limits a positive impact of the inclusions on the coatings properties. It is known [1], that additional introduction of disperse titanium carbide particles into the coating structure results in considerable hardness and wear resistance gain of the laser cladded coatings. An advantage of the titanium carbide under other metal carbides is a maximum hardness and equal-axes shape of the inclusions. The most effective method to introduce TiC particles into metal matrix is self-propagating high temperature synthesis (SHS) in reactive powder mixtures of titanium, carbon and metal or alloy resulting in the metal binder [2]. In the present work phase composition and structure of “TiC - NiCrBSi alloy binder” metal matrix composite powders have been investigated. The composite powders were produced by crushing of SHS cakes. The cakes were synthesized from titanium, black carbon and Ni77Cr15Si3B2 alloy reaction powder mixtures. According to X-ray diffractometry basic phases in SHS products are titanium carbide of non- stoichiometry, carbon deficit composition and nichrome: chromium – nickel solid solution. The total content of the strengthening phases (carbides, borides and silicides) does not exceed 8 %. By microstructure investigation of SHS products it was found, that an average size of the carbide inclusions in the metal binder falls monotonously as NiCrBSi powder content in reactive mixtures rises. (fig. 1). Dependence of this type is typical for reactions in the mixtures with thermally inert dopants [2]. The reason is a burning temperature drop (fig. 2) by the alloy powder, that is not involved in the reaction.

Fig. 1. Volume binder content in SHS powders Fig. 2. Volume binder content in SHS powders dependence of TiC inclusion size dependence of burning temperature

The synthesized powders were used for electron beam cladding and for plasma sputtering of the coatings. The cladded coatings have abrasive wear resistance up to 2,5 times above, than that cladded by Ni77Cr15Si3B2 powder while hardness increase does not exceed 30 %. REFERENCES [1] R.L. Sun, Y.W. Lei, W. Niu. // Surface and Coatins Technology. 2009. 203. Pp. 1395-1399. [2] A.S. Rogachev, A.S. Mukasyan // Combustion for materials synthesis, Fizmatlit Publ., Moscow, 2013. (Russ).

624 ______Functional materials and coatings

EFFECT OF ALLOYING ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mo-Fe-B BORIDE HARD ALLOYS

M.B. IVANOV*, T.N. VERSHININA*, V.V. IVANISENKO* *Belgorod National Research University, Pobedy st., Belgorod, 308015, Russian Federation, [email protected], +7(4722)58-54-08

Hard alloys based on ternary borides (Mo2FeB2 and Mo2NiB2) are potential candidates for partial substitution of hard alloys based on tungsten carbide in the industry. These hard alloys (cermets) have excellent combination of hardness, toughness, corrosion resistance, and a coefficient of thermal expansion close to steel [1, 2]. Mo2FeB2 based cermets attract much attention because of cheap raw material and simple preparation method. This method is known as boronizing sintering and associated with formation of ternary boride cermets in metal matrix during liquid phase sintering [3]. Generation of liquid phase makes it possible to reduce the reacting temperature and consequently reduce temperature of the cermets production. The purpose of this investigation is to determine the effect of Ni, Cr and C addition on the microstructure, phase composition and mechanical properties of Mo2FeB2 based hard alloys. a b

Fig. 1. Microstructure of the cermets with nickel contents of: (a) 0 wt.%; (b) 0.5 wt.%; The results reveal that alloying of cermet with small amount of nickel leads to the transformation of binder phase from ferrite to austenite. With the increase of Ni content two types of ternary borides Mo2FeB2 and Mo2NiB2 can be formed (Fig.1). Chromium addition changes the shape of the boride from closed angle to equiaxial structure and leads to grain refinement of borides. The hardness increased with the increasing of Cr concentration. Doping with carbon of cermets alloyed by chromium is accompanied by M6C and M23C6 carbides formation and reduction of binder phase volume fraction. These factors lead to an increase in hardness and a decrease in crack resistance in cermets with high carbon content. REFERENCES [1] Ide T., Ando T.// Metall Mater Trans A. - 1989. -Vol. 20. -P.17–24. [2] Nishiyama K., Keino M., Furuyama Y. et. al. // J Alloys Compd. - 2003. - Vol.355. -P. 97–102. [3] Takagi K. // Journal of Solid State Chemistry. -2006. - Vol. 179. - Is. 9. - P. 2809-2818.

625 ______Functional materials and coatings SYNTHESIS OF FILMS AND N-P-STRUCTURES BASED ON COPPER AND ZINC OXIDES USING MAGNETRON SPUTTERING

D.V. ISMAILOV1,2

1Tomsk Polytechnic University, Institute of High Technology Physics, 30, Lenin Avenue, Tomsk, 634050,Russia. 2 National Nanotechnology Laboratory of open type of Kazakh National University Al-Farabi, 71, Al-Farabi, Almaty, 050012 Kazakhstan, e-mail:[email protected], Phone: +77784233448

Abstract The results of obtaining zinc oxide films and ZnO/Cu2O(CuO) heterojunctions are presented. Structural, optical and electrical properties of the samples were studied depending on synthesis conditions. ZnO films were grown by magnetron sputtering. The synthesized films with a thickness of about 0.3 micron had a resistivity of 0.0014 Ohm*cm, mobility of 4.5 cm2/(V×s), free electron concentration of 1×1021 cm-3, and a surface resistance of about 45 ohms per square. The optical transmission coefficient of ZnO films in the visible region was about 90%. Heterojunctions n-ZnO/p-Cu2O(CuO) were obtained by vacuum deposition of copper on ZnO film followed by annealing. The effect of thermal annealing and plasma treatment on the properties of ZnO/Cu2O(CuO) samples was investigated. The photoresponse of heterojunctions was found to be increased, and leakage current was reduced as a result of short-term treatment in a hydrogen plasma. Key words: electrical conductivity of ZnO films; properties of zinc and copper oxides; magnetron sputtering method; synthesis; vacuum annealing; nanoparticles; nanostructures; crystallization. Introduction Recently, there has been an increasing interest in heterojunctions based on zinc and copper oxides, which is associated with the wide possibilities of their practical application, in particular for the creation of various types of detectors, photo- and optoelectronic devices [1-2]. Thus, high values of electrical conductivity of ZnO films and transparency in the visible range of the spectrum make it possible to produce transparent conductive electrodes for solar cells and other devices, various sensors and detectors, piezoelectric devices based on zinc oxide [3-6]. Experiment Uniform ZnO films on glass substrates ~2×2 cm2 were obtained from a ceramic ZnO target by DC magnetron sputtering. Previously, glass substrates were thoroughly cleaned by boiling in acetone, ethanol and washed with deionized water. Deposition of films was carried out in the argon atmosphere at a pressure of 10-3 atm, a voltage of 400V, a current of 200 mA, the substrate was at room temperature. The surface morphology of the ZnO samples obtained by magnetron sputtering, were studied on a scanning electron microscope (SEM) Quanta 200i 3D (FEI). Optical transmission spectra of the obtained ZnO films were measured using Lambda-35 spectrophotometer (PerkinElmer). The electrical parameters of the ZnO films were determined by measuring the specific resistance and carrier concentration by the Hall effect in the van der Pau configuration by a four-probe method at room temperature using the HMS-3000 (Ecopia) unit with a 0.55 T magnetostatic magnet. The current-voltage curves of obtained structures were measured by the Elins P-30J potentiostat in a two-electrode circuit using clamping gold contacts.

1. Y. Zhu, C.-H. Sow, T. Yu, Q. Zhao, P. Li, Z. Shen, D. Yu, J.T.-L. Thong//Adv. Funct. Mater.- 2006. - Volume 16. – Pages 2415. 2. C.S. Dandeneau, Y.H. Jeon, C.T. Shelton, T.K. Plant, D.P. Cann, B.J. Gibbons//Thin Solid Films - 2009. - Volume 517. – Pages 4448. 3. Z.L. Wang// Materials Today. - 2004. - Volume 7. № 6. - Pages 26. 4. L. Schmidt-Mende, J.L. MacManus-Driscoll//Materials Today. - 2007. - Volume 10. № 5. – Pages 40. 5. S.K. Gupta, A. Joshi, M. Kaur, J. Chem.//Sci. – 2010. - Volume 10. № 2. – Pages 57. 6. M. Law, L.E. Green, J.C. Johnson, R. Saykally, P. Yang, Nat.//Mater.- 2005. - Volume 4. – Pages 57455.

626 ______Functional materials and coatings

APPLICATION OF ION-ELECTRON TECHNOLOGY FOR MODIFYING NEAR-SURFACE LAYERS OF A SILICON SUBSTRATE FOR CREATING ELEMENTS OF MICROMECHANICAL SYSTEMS

I.A. BULYCHEV *, N.V. VOLKOV *, I.V. OLEINIKOV *, N.V. SYSOEVA *, V.V. SAMOILOV *, S.P. TIMOSHENKOV ** * National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse,31, Moscow, 115409, Russia, [email protected], +7 495 788-5699 ** National Research University of Electronic Technology – MIET, Shokin Square, 1, Zelenograd, Moscow, 124498, Russia, [email protected], +7 (499) 731-44-41

For the production of sensors, the principle of functioning of which is based on changing the electrical capacity, methods are used to create volumetric structures with the greatest thickness and minimum clearance between moving and stationary parts of the sensor, for example, plasma chemical etching. It is believed that this technology provides the best ratio of the depth of the etching profile to its width and channel width to its length at the minimum dimensions of the element. At present, depending on the complexity of the MEMS structure, 5 to 25 operations are required to ensure a minimum thickness of a single layer (0.1-10 μm). The paper presents the results of studying the possibility of using ion beam technology and Double Beam technology (electron and ion beam alignment) used in electron microscopy to create MEMS elements with high-profile three-dimensional structures of small and medium complexity. The preparatory irradiation of the Si substrate was performed by He+ and Ar+ ion beams at the VOKAL unit, forming an ion beam with a wide continuous Gaussian energy spectrum with an average energy of 10 keV (radiation dose 1 and 5×1017 ion/cm2, residual gas pressure below 5×10-5 Pa, the irradiation temperature is <50 ° C), and etching (excision of MEMS elements) was carried out with Ga+ ions on an ion microscope "VERSA 3D" under close conditions. It is established that when a beam of ions is irradiated by a wide energy spectrum, a developed surface relief is formed with a characteristic sub-roughness value of 10-50 nm, which is due to the presence of interstitial gas atoms in the near-surface layer of the material. It is shown that the maximum penetration depth of Be and Al atoms linearly depends on the irradiation dose of He+ and Ar+ and reaches a depth of 0.5-1.0 μm at the concentration of interstitial atoms of the order of 10-3 at.%. Analysis of the results of treatment with a Ga+ ion beam showed that it is possible to create three-dimensional structures - MEMS elements with parameters of gaps of 0.1-0.2 μm at depths up to 2 μm on an ion-modified Si-site with dimensions of 5-10 μm.

627 ______Functional materials and coatings

THE INFLUENCE OF «FREQUENCY OPERATION» MODE OF COAXIAL MAGNETOPLASMA ACCELERATOR ON THE PHASE COMPOSITION IN THE «FE-O» SYSTEM

M.I.GUKOV*, A.I.TSIMMERMAN*, A.E.YURTAEVA* *Student of National research Tomsk Polytechnic University Lenin Avenue 30, Tomsk, 634050, Russia, [email protected], +7(999)177-51-90

In the "iron-oxygen" system, there are 6 known phases of iron oxides such as α-Fe2O3 (hematite), β- Fe2O3, γ-Fe2O3 (maghemite), ε-Fe2O3, FeO and Fe3O4 (magnetite), which have different structural and physical properties. Among them, ε-Fe2O3 phase is of the greatest practical interest due to its unique magnetic properties. For example, ε-Fe2O3 phase has the highest coercivity among all known simple metal oxides (~ 23 kOe) [1]. Also it has the ferromagnetic resonance at the frequency of 182 GHz [2]. Nonetheless, the production of epsilon phase is a difficult scientific task, because of the fact that they can exist only in a nanoscale state and thermodynamically unstable. It is known that the method of plasmodynamic synthesis can be used to obtain the epsilon phase of iron oxide [3], however its yield in the final product is not enough to study its properties correctly. This is due to the fact that the product of plasma dynamic synthesis generally consists of three phases (magnetite, hematite and epsilon phase). The presence of other iron oxide phases is able to contribute an error in the measured parameters. Thus, in this paper we considered the possibility to increase the yield of epsilon phase by means of using the "frequency" operation mode of the coaxial magnetoplasma accelerator (CMPA). This “frequency” mode is realized by feeding to the CMPA with several consequitive discharged pulses of power supply. The influence of “frequency” mode was studied by implemening the plasma dynamic synthesis in a series of experiments differing by the number of power supply pulses (from 1 to 4). The ultrafine powdered products obtained in every experiment were investigated using the X-ray diffractometry and scanning electron microscopy methods. The quantitative estimation of phase content was carried out using PDF2+ database and “PowderCell 2.4” software. It was found that the yield of epsilon phase strongly depends on number of pulses. For example, with increasing in the number of pulses from 2 to 4 the ε-Fe2O3 content was increased from 35,0 to 65,0 %. It is also should be noted that the product mass in the case of 1 power supply pulse was too insufficient to study its phase composition. Such process feature is connected with the initial energy parameters, which were chosen in such a way to increase the lifetime of the CMPA electrode system. Thus, it was found that the yield of epsilon phase in the considered system directly depends on the number of power supply pulses.

REFERENCES [1] Ohkoshi S. et al. // Journal of applied physics. – 2005. – Vol. 97. – №. 10. p. № 10K312. [2] Yoshikiyo M. et al. // Journal of applied physics. – 2014. – Vol. 115. – №. 17. p. № 172613. [3] Sivkov A. et al. // Journal of Magnetism and Magnetic Materials. – 2016. – Vol. 405. – pp. № 158-168.

628 ______Functional materials and coatings

APPLICATION OF THE CYCLIC REACTOR OF COMPRESSION FOR THE PRODUCTION OF THE SILICON CARBIDE NANOPOWDER1

B.S.EZDIN*, V.V.KALYADA*, A.E.ZARVIN*, A.V.ICHSHENKO*, A.A.NIKIFOROV* *Novosibirsk State University, st. Pirogova, Novosibirsk, 630090, Russia, [email protected], +7(383)3634298

The unique physico-chemical properties of silicon carbide, its use in nanodispersed form, allows to obtain new functional materials with predefined physical properties, including for the design of electronic components with high performance characteristics. Despite a rather large number of works, the problem of obtaining a nanoscale silicon carbide powder of the required parameters for purity, dispersion, productivity and other characteristics remains relevant. There are a number of methods for obtaining a nanosized silicon carbide powder, such as sol-gel [1], laser pyrolysis [2], self-propagating high-temperature synthesis [3], plasma chemical method [4], adiabatic compression method [5]. The disadvantage of these methods is low productivity, the difficulty of scaling and the need to use expensive unique equipment, as a result of which the cost of nanoscale powders becomes high. Our method uses a cyclic method of compressing the initial gaseous reagents of a mixture of gases SiH4, Ar and light hydrocarbons in the volume of a chemical reactor. The chemical compression reactor used is described quite fully in [6]. The passage of the SiC synthesis reaction was monitored on-line using a universal gas analyzer UGA- 200. The samples were characterized by the HRTEM method using the JEM-2010 electron microscope equipped with the EDS spectrometer QUANTAX 200-TEM for local element analysis. In Fig. 1 shows typical electron microscopic images of the morphology and structure of the samples obtained.

Fig. 1 Electron-microscopic images of particles of a sample of nanodispersed silicon carbide. Dimensions of silicon carbide particles vary in the range of 10-40 nm. The observed interplanar distances correspond to silicon carbide from the XRD database. The proposed method for obtaining nanoscale silicon carbide is convenient for technological execution. The process is cyclical and fully automatic. The degree of processing of the reagents reaches a high level. The product obtained during the synthesis of nanoscale SiC is chemically pure and is determined only by the degree of purification of the initial reagents, technological processes do not add additional contaminants to the product. The resulting product does not require further processing, as in most known methods and is ready for use in technologies and tasks of materials science. REFERENCES 1. I.S.Seog,C.H.Kim // J.Mater.Sci. 1993, Vol. 28(12), P. 3277-3282 2. P. Tougne, H. Hommel, A. Legrand, N. Nerlin, M. Luce, M. Cauchetier // Diamond Related Mater. 1993, vol.2, P.486-492. 3. J. Narayan, R. Raghunathan, R. Chowdhury, K. Jagannadham // J. Appl. Phys. 1994. Vol.75, P.7252-7257 4. A.S.Anshakov, E.K.Urbach, A.E.Urbach, et al.// Thermophysics and Aeromechanics, 2017, Vol.24, No.3. P. 473-482. 5. G.A. Pozdnyakov, V.N. Yakovlev, A.I. Saprykin // Dokl. Phys. Chem., 2017, Vol. 476, Part 1, P. 165–168. 6. B.S.Ezdin, A.E.Zarvin, V.V.Kalyada, A.S.Yaskin // Chem.Petr.Eng. 2016, Vol.52, P. 26-28

______

1The work was carried out using the equipment of the Center "Applied Physics" NSU with the financial support of the Ministry of Education and Science of the Russian Federation, grants 3.5918.2017 / ITR, 3.5920.2017 / ITR 629 ______Functional materials and coatings

THE PULSE CURRENT RELEASE PROPERTIES OF GLASS-ADDED LEAD LANTHANUM ZIRCONATE TITANATE STANNATE ANTIFERROELECTRIC CERAMICS

H. TANG*, Z. JIANG*, T. WU*, Y. FENG** * Chongqing University of Arts and Sciences, No. 319, Honghe Road, Yongchuan, Chongqing, 402160, China, E-mail:[email protected], +86 17347610677 **Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an, 710049, China,

In this paper, properties of Pb0.91La0.06[(Zr0.70Sn0.30)0.84Ti0.16]O3 (PLZST) with glass added were studied. The glass was added to PLZST in weight percent:0.2%wt0.4%wt0.6%wt0.8%wt1.0%wt and 5.0%wt. All the glass added PLZST samples were fabricated with solid reaction method and can be well sintered under 1250 while PLZST sintering temperature is 1300. The hysteresis of glass added PLZST ceramic exibited amormal in low electric field and the maximum polarization decreased intensively with increasing glass content. The dielectric permittivities verses temperature curves showed more dispersive and the Curie temerature increased with increasing glass content. Pulse current release properties of PLZST showed increasing maximum discharge current and discharge period with increasing electric voltage. Breakdown strength can be raised by adding 1%wt glass in PLZST . The energy storage density decreased with glass addition because of severe decrease in maximum polarization.

Fig.1. Charge release current of PLZST under 3000V

Fig. 2. The maximum current release and period changing of PLZST ceramics under voltage of 1000V to 3000V

REFERENCES [1] Smolenskii GA, Bokov VA, Isupov VA, et al. Ferroelectrics and related materials[M]. New York. Gordon and Breach Science Publishers, 1984. [2] Ma C, Tan X, Dul’kin E, et al. J. Appl. Phys., 2010, 108: 104105-1-104105-8. Pennycook SJ, Jesson DE, McGibbon AJ, et a1. J. Electron Microsc.,1996,45:36-43

630 ______Functional materials and coatings

UNSTABLE PLASTIC DEFORMATION IN BIMETAL1

Y.V. LI*, S.A. BARANNIKOVA*, L.B. ZUEV* * Institute of Strength Physics and Materials Science, SB RAS, 2/4, pr. Akademicheskii, Tomsk, 634055, Russia, [email protected]

Unstable plastic deformation of metals and alloys at the macroscopic level is manifested in the form of a sharp yield point, neck formation and discontinuous deformation [1]. The bands of macrolocalized deformation accompanying jumps of deformation and/or stresses impair the industrial products surface quality, cause their premature corrosion and increase the probability of sudden destruction. Studies of the nonuniformity of materials deformation had been previously made in detail on specimens of pure metals and alloys [2]. This paper considers the deformation behavior of a corrosion-resistant bimetal – carbon steel - stainless steel – which is used in chemical engineering for the manufacturing of reaction columns, autoclaves, reactors and heat exchangers [3]. Pre-prepared bimetallic samples in the form of a double dog bone with the dimensions of the working section 42×8×2 mm were extended at T = 300K at a rate of 6,67×10-5с-1 on LFM-125 test machine. Visualization of the localized plastic deformation bands and registration of their proliferation kinetics was carried out at the working portion of the sample by the length of 42 mm by two non-contact methods: the method of digital image speckle correlation and the method of digital statistic speckle photography [4]. The research conducted allowed to identify the main patterns of proliferation of localized zones of plastic deformation in the bimetal. It is revealed that plastic deformation start from Lüders band (LB) formation in the main layer of the A 283 Grade C material. The average propagation velocity of the bands in the main layer material (A 283 Grade C) is Vaw.= 0.8•10-4 m/s and Vaw.= 2.4•10-4 m/s in the upper cladding layer of the material A 283 Grade C the Lüders bands front propagate with velocities Vaw = 2.4 • 10-4 m / s, Vaw = 0.7 • 10-4 m/s, Vaw = 2.3 • 10-4 m/s. To compare the data, note that when analyzing the patterns of localization of deformation of samples of 321 AISI low-carbon steel and A 283 Grade C steel under tension, the following was revealed. The generation of localized fronts in 321 AISI steel corresponds to the total deformation of εtot= 0.6 %. As a result, one LB front propagates throughout the yield plateau with the velocity Vaw = 1.1 • 10-4 m/s. The zones of localized plastic deformation are formed in A 283 Grade C steel when total deformation of εtot= 40 %. The sequences of the plastic deformation localization zones are found at the linear-hardening stage, their propagation velocities are Vaw.= 2.1•10-4 m/s, Vaw.= 1.7•10-4 m/s, Vaw.= 1.3•10-4 m/s. From the data of the experimental results, it can be concluded that in the process of deformation of the materials, bands of localized plastic deformation are observed in both single-layer materials and in multilayered metallic materials. The main difference between them lies in the nature of the propagation and the place where this fronts arisen.

REFERENCES [1] Zuev L. B, Barannikova S. A // Int. J. Mec. Sci.  2014.  V. 88. P. 1-7. [2] Venkateswara N, Madhusudhan G, Nagarjuna S // S. Mater. Des. – 2011. - V. 32. P. 2496-2506. [3] Guobin L, Jianjun W, Xiangzhi L. Guiyun L // J. Mater. Proc. Technol. – 1998. - V. 75. P. 152-156. [4] Sokoli D, Shekarchi W, Buenrostro. E, Wassim M // An Int'l Journa. – 2014. - V. 7. P. 609-626.

1 The work was performed in the frame of Russian Foundation for Basic Research (grant N 16-19-10025)

631 ______Functional materials and coatings ON THE DIRECT RELATIONSHIP BETWEEN MACROSCOPIC PHENOMENA OF PLASTIC FLOW LOCALIZATION AND SOLIDS MICROCHARACTERISTICS1 Y.V. LI*, A.M. ZHARMUKHAMBETOVA**, S.A. BARANNIKOVA*, L.B. ZUEV* * Institute of Strength Physics and Materials Science, SB RAS, 2/4, pr. Akademicheskii, Tomsk, 634055, Russia, [email protected] ** Tomsk State University, 36, pr. Lenina, Tomsk, 634050, Russia

It is known that plastic flow tends to localize from yield point to ductile failure [1]. Interpretation of experimental data on flow macrolocalization is a complicated task that still remains to be solved. To date the phenomenology of the localization effect has been elucidated and the space-time regularities, which are characteristic for localization development, have been established. Localization might be regarded as a typical example of self-organization if the term “self-organization” is used in the meaning proposed by Haken, i.e. acquisition by a system of a spatial, a temporal or a functional structure in the absence of any specific action from without [2]. Plastic flow localization has all the characteristic features of autowave processes [1]. Thus at the stage of linear work hardening, the localization of plastic flow occurs in the form 5 4 of phase autowaves having length 5    15 mmand propagation velocity 10  Vaw  10 m/s. A special technique of double-exposure speckle photography intended for visualization of localized plasticity patterns has been developed [1]. This enabled one to obtain a vast array of data on the above quantities for a range of materials. The present paper contains an attempt to reveal relationships between the above waves and the

microscopic characteristics of the deforming medium. The wavelength, , and the propagation velocity, Vaw , were measured at the linear work hardening stage for the tested specimens of Cu, Ni, Al, Sn, Fe, V and Zr. The speckle-interferometry technique developed specially for similar investigations was used. On the base of experimental data a close correlation has been established between the product of auto-

wave macroscopic parameters,  Vaw , and that of material microscopic parameters, Vd  (here d is the

spacing between close-packed planes of the lattice and V is the rate of transverse elastic waves). In each instance, the following equality apparently holds good within an acceptable range of accuracy, i.e.,

 aw 2/1  VdV  (1) where, the terms have the units of the diffusion coefficient L2·T-1. To verify relation (1), we used borrowed 2  VdV values of d and V [3, 4]. Relation (1) was averaged for linear work hardening stages as aw   (1.04 V  0.14)  1. Eq. (1) relates the micro-scale characteristics d and  , which are observed for elastic waves propagating in crystals, to the macro-scale parameters  and , which are observed for elastic waves propagating in crystals, to the macro-scale parameters  and Vaw , which are obtained for localized plastic flow auto-waves generated in the same crystals. The products of these values, Vd  and  Vaw , are invariants for elastic and plastic deformation processes, respectively ( << 1 and   1, respectively). The above regularity stems from the fact that the processes of elastic and plastic deformation are closely related. In the course of deformation the redistribution of elastic stresses occurs via micro-scale processes at the rate , while the rearrangement of localized plastic flow nuclei involves macro-scale processes occurring at the rate Vaw , with the processes of both types being related by Eq. (1). Thus, the macro-localization phenomena must be regarded as an attribute of plastic deformation rather than a random disturbance of plastic flow homogeneity.

REFERENCES [1] Zuev L. B, Barannikova S. A // Int. J. Mec. Sci.  2014.  V. 88. P. 1-7. [2] H. Haken // Information and Self-Organization. A Macroscopic Approach to Complex Systems. - Springer Verlag, Berlin, 1988. [3] J.D.H. Donnay // Crystal Data, Determinate Tables. - Williams and Heintz Map Corp., Washington, 1963. [4] O.L. Anderson // Determination and some applications of the isotropic elastic constants of polycrystalline systems, obtained from single crystals data. - W. P. Mason, (Ed.) Physical Acoustics. Principles and Methods, 3B, Academic Press, New York, 1965.

1 This work was supported by the Program of Fundamental Research of State Academies of Sciences for the period 2013-2020 yrs.

632 ______Functional materials and coatings

PRODUCTION OF CERAMIC MATERIALS BASED ON THE SYSTEM OF CO-CR-O, CE-O BY THE METHOD OF SHS.

SHULPEKOV A.M. Tomsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Akademichesky Ave. 10/4, Tomsk, 634055, Russia [email protected], +7(3822)492294

Nanodisperse powders based on oxides of cobalt, chromium, cerium are used as pigments, catalysts for various organic reactions. Traditional methods of synthesis of such materials - solid-phase or sol-gel synthesis have a number of drawbacks. A more promising method at present is the sol-gel combustion method. This method is simple, has low energy costs, has no by-products or production waste [1]. The aim of the work is to study the regularities of the processes occurring in the SHS process of nanosized oxide ceramic materials based on the Co-Cr-O, Ce-O system and the study of their functional properties. The regularities of the SHS process in the combustion of sol-gel systems based on Co, Cr, Ce nitrates have been studied. To aqueous solutions of cobalt nitrate, chromium (0.4 mol / l) or their equimolar mixture, sucrose was added as a reducing agent and dried at a temperature of no higher than 40 °C. The gel obtained as a powder was used as a precursor for the synthesis. From the precursor solution, coatings on porous ceramics were applied by the method of multiple dipping, followed by drying at 100-150 °C and final firing in air at 350-700 °C. To study the process of thermal decomposition of precursors, a gel powder weighing 0.5-3 g was placed in a crucible that was installed in an electric furnace, which was supplied with an alternating voltage of 100- 150 V from an autotransformer. The thermocouple was placed directly into the test gel, which was connected to the LA20 USB ADC and a personal computer. In addition, a second thermocouple located at the inner wall of the furnace was monitored for temperature. Thermograms are shown in Fig. 1.

1000 1

800 2 1 С 0 600

400 2 Intensity Temperature, 200

3 0

0 200 400 600 800 1000 1200 20 40 60 80 100 time, sec grad

Fig. 1 Thermogram of a mixture of cobalt, chromium and Fig. 2 X-ray diffraction patterns of the decomposition product of an sugar nitrates (50% by weight) equimolar mixture of cobalt and chromium nitrates with sugar. The 1 - autoignition mode, 2 - decomposition of the mixture. content of sucrose in a mixture of 1 to 30, 2 to 50, 3 to 70 wt. %.

A coating technique based on CoCr2O4 and CeO2, distributed in a porous layer of alumina, has been developed. The coating was applied by impregnating the product in a tributoxy aluminum solution with the addition of an equimolar mixture of cobalt and chromium nitrates or cerium nitrate followed by heat treatment. The method of differential thermal analysis, X-ray diffraction analysis (Figure 2), and IR spectroscopy showed that at a temperature above 300-400 °C, porous alumina is formed with the submicron particles of CoCr2O4 cobalt-chromium spinel or CeO2 cerium oxide distributed therein. It is shown that the coatings obtained have catalytic activity in the processes of deep oxidation of hydrocarbons. Coatings allow to reduce CO and NOx content in combustion products of methane-air mixture.

REFERENCES [1] Rogachev AS, Mukasyan AS // Burning for the synthesis of materials: introduction to structural macrokinetics. - Moscow: FIZMATLIT, 2013.

633 ______Functional materials and coatings

COATING IN THE NI-AL SYSTEM USING THE SHS METHOD

A.M. SHULPEKOV, R.M. GABBASOV Tomsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Akademichesky Ave. 10/4, Tomsk, 634055, Russia [email protected], +7(3822)492294

Intermetallides formed in the Ni-Al system have high heat resistance, heat resistance and electrical conductivity. Therefore, such materials are promising for use in high-temperature film electric heaters. SHS processes in the Ni-Al system have been studied in sufficient detail. However, such studies were carried out for samples pressed from powders in the form of a cylinder. For samples in the form of coatings, studies of processes in the combustion wave, the regularities of the change in velocity, and other parameters of the process have not been practically carried out. Therefore, such studies are relevant. The aim of the work is to study the influence of the layer thickness and the degree of dilution of the initial mixture with an inert diluent on the temperature and speed of propagation of the combustion wave, the structure and electrical conductivity of the coating. To prepare the coating, a mixture of nickel and aluminum powders in the form of a suspension in isopropyl alcohol was applied to a VK-1 ceramic plate through a stencil 0.3 to 2 mm thick, 20 mm wide, and air dried at room temperature. The THA thermocouples were fixed at a distance of 35 mm from each other. To register thermograms, thermocouples were connected to the ADC and a personal computer. The propagation velocity was determined by the delay of the signal from the two thermocouples. The structure of the coating was studied by X-ray phase analysis and optical microscopy.

a) b)

Fig. 1The thermogram of the SHS process a) and the diffraction pattern of the coating b). Phases: 1 – NiAl, 2 – Ni3Al. The process thermogram is shown in Fig. 1a. Studies have shown that the temperature in the combustion wave is significantly lower than for cylindrical samples of similar composition. This is explained by the large heat dissipation of flat samples. The propagation velocity of the wave (about 10 mm / s) is also considerably smaller than for cylindrical samples of the same composition. The dependence of the maximum temperature of the combustion wave and its propagation velocity on the coating thickness and the degree of dilution of the powder mixture with an inert substance is studied.

a) b) Fig. 2 Appearance of the coating a) and its microstructure b).

X-ray phase analysis showed that the coating contains the NiAl and Ni3Al phases (Fig. 1b). The predominant phase is NiAl. This indicates a significant underreaction in the combustion wave. Increasing the coating thickness increases the concentration of the target NiAl phase. The coating consists of small crystals fused together (Figure 2a). In addition, in Fig. 2b that the front is not flat. The electrical resistance of the coating is 2-5 Ω and decreases with increasing coating thickness. Thus, in the course of the work, the influence of the coating thickness and the degree of dilution of the powder mixture with an inert substance on the maximum temperature of the combustion wave and its propagation velocity is shown. It is shown that the coating consists of small crystals of NiAl, Ni3Al, fused together. The coating has good electrical conductivity and can be used as electric heaters. The obtained experimental data served to construct a mathematical model of the process.

634 ______Functional materials and coatings NANOSIZED MAGNETIC POWDERS BASED ON OXIDES FOR MEDICINE AND BIOLOGY A.A. NEVMYVAKA*, A.G. PERSHINA**, V.I. ITIN* *Tomsk Scientific Center SB RAS, 10/4, Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294 **Siberian State Medical University, 2, Moskovsky, 634050, Russia, [email protected]

The stoichiometric and nonstoichiometric nanosized powders of oxide cubic ferrimagnetics (Fe 3O4,

CoxFe3-xO4, NixFe3-xO4, MnxFe3-xO4, etc.), tin and zinc oxides, and also the composite material SnO2 + Fe3O4 with a high value of a specific surface (120-190 m2/g) were obtained by the method of mechanochemical synthesis from salt systems. The size distribution includes spherical nanoparticles with a diameter from 3 to 15 nm. During mechanochemical synthesis, intense deformation (impact, friction) is found to lead to the formation of «active» non-equilibrium states in nanoparticles, which are characterized by non-stoichiometry, high elastic microstresses, change in the degree of order in the arrangement of ions of different types, change in lattice parameters, and amorphization of a surface layer. The study have shown essential changes in the fundamental magnetic properties of cubic ferrite nanopowders as compared with bulk samples, which is caused by the large contribution of surface anisotropy and the magnetoelastic component. When a structural element decreases from 10 5 to 2-15 nm, a ferrimagnetic acquires the properties of a spin cluster glass with a high blocking temperature. The results showed the aging of nanosized powders of cubic oxide ferrimagnetics obtained by the method of mechanochemical synthesis, which was manifested as a change in the phase composition, structural parameters, and basic magnetic properties. The synthesized nanopowders of cubic oxide ferrimagnetics were studied for the purpose of using in medicine and biology for pharmokinetic studies, as well as for separation and purification of biological substances. Thus, the results obtained have shown that the nanosized cobalt ferrospinel powder possesses a sorption activity relative to DNA and protein molecules (for example, bovine serum albumin and Taq polymerase enzyme). The results of DNA are well presented for the SnO2+Fe3O4 composite material. As a result, new sorbents and functional bionanocomposites stable in aqueous buffer solutions and controlled by an external magnetic field were created. Ferrite nanopowders were used to study the stability and activity of enzymes which are widely used in clinical diagnostics (PCR) and molecular and biological studies. Immobilization of cobalt ferrospinel nanoparticles was found to prolong significantly the enzymic activity at room temperature. After holding for 40 days, the residual activity of enzyme, not adsorbed on nanoparticles, is no more than 3% of the initial one, while enzyme immobilized on nanoparticles retains more than 40% of the initial activity for 250 days. The absence of a strong chemical bond between enzymes and nanoparticles and the magnetic properties of nanoparticles allow us, if necessary, to remove nanoparticles from reaction mixtures or enzymic agents by the magnetic separation method. The interaction of DNA with cobalt ferrospinel nanoparticles was studied to create a new nanobiocomplex (bionanoconjugate) for the detection and separation of nucleic acids (DNA and RNA) from solutions and the method of its obtaining. This result can be used in the development of new methods for molecular and genetic diagnostics.

635 ______Functional materials and coatings EFFECT OF ALUMINIUM OXIDE AND ASH MICROSPHERES ON NITRIDING OF 1 ALUMINIUM FERROSILICON IN THE COMBUSTION MODE

K.A. BOLGARU*, A.A. AKULINKIN

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634021, Russia, [email protected], +7(3822)492294

β-Sialons are solid solutions with a variable composition Si6-zAlzOzN8-z formed on the basis of β- Si3N4 by substitution of Si → Al and N → O (z is the number of substituted silicon and nitrogen atoms in the formula of silicon nitride and is changed in the range from 0 to 4.2). These compounds are stable at high temperatures (1500-1800 °C), demonstrate high corrosion, heat and wear resistance, significant hardness and strength [1] and are currently considered to be technologically and commercially promising materials. As a rule, the synthesis of sialons is combined with the hot pressing of mixtures from preformed powders of

Si3N4, AlN and Al2O3, which results in high costs of ceramic materials. The process of production becomes much simpler and the costs of sialon ceramics are reduced if green mixtures used for the production of ceramics are not subjected to deep chemical cleaning, for example, aluminosilicate minerals or iron- containing alloys. As shown in [2], even if sialon ceramics contains iron in significant amount (about 10%), such ceramics has high performance characteristics. Ferroalloys that contain both nitride-forming elements in the composition of sialon (aluminum and silicon) are of particular interest. Aluminium ferrosilicon (grade FS65F15), aluminium oxide and ash microspheres were used as green mixtures. Samples were burned in a constant-pressure device according to the procedure in [3]. The nitriding of aluminium ferrosilicon in the presence of ash microspheres in the amount of more than 10 wt.% allows the nonstationary combustion to be changed to the stationary one. The combustion product is a sintered porous homogeneous material. As studies have shown, the pore size of the sample is usually determined by the particle size of ash microspheres. When the amount of an added green mixture was more than 25 wt.%, the combustion of aluminium ferrosilicon was not observed.

Aluminium oxide (α-Al2O3) was added to the green mixture in the amount of 5-22% to achieve the maximum possible nitriding degree of synthesis products and obtain β-sialon with a composition of Si3Al3O3N5. When the amount of Al2O3 was more than 22%, the combustion of aluminium ferrosilicon was not observed. A detailed study of a diffraction profile for the combustion products of aluminium ferrosilicon in the presence of Al2O3 showed that all diffraction maxima shifted toward smaller angles (2θ). It is seen that an increase in the amount of aluminium oxide leads to the fact that the crystal lattice parameters approach the reference values for β-Si3Al3O3N5 and reach the maximum matching for 22% of Al2O3. In this case, a two- phase combustion product consisting of β - Si3Al3O3N5 and α-Fe is formed. In general, ash microspheres can be used to change a surface combustion mode to a layered one, which allows us to obtain a sample with a homogeneous macrostructure, and a sintered porous material as well. The study has shown that the final product of aluminium ferrosilicon nitriding in the combustion mode is a two- phase material consisting of β – Si3Al3O3N5 and α-Fe, for the case when the amount of Al2O3 added to the initial ferroalloy was 22 wt.%. REFERENCES [1] Grigoryev O.N., Vinokurov V.B., Panasyuk A.D., Bega N.D., Garbuz V.V. // Powder metallurgy. - 2003. - No. 7/8. - P. 65-70. [2] Zeng J., Y.Miyamoto, O. Yamada // J. Amer. Ceram. Soc. – 1990. – Vol. 73, № 12. – P. 3700-3701. [3] Merzhanov A.G., Borovinskaya B.P. Self-propagating high-temperature synthesis of refractory inorganic compounds // Dokl. AN SSSR. - 1972. - V. 204.- No.2. - P. 366-369.

1 The work was carried out within the state task of FASO (No. 0365-2018-0002) and partially supported by the Russian Foundation for Basic Research (No. 18-33- 00387 mol_a).

636 ______Functional materials and coatings

NONISOTHERMAL SYNTHESIS AND STUDY OF THE STRUCTURE AND PHASE COMPOSITION OF TITANIUM-CONTAINING NANOLAMINATE COMPOUNDS

О О .K. LEPAKOVA , N.I. AFANASYEV, А.M. SHULPEKOV

Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294

Nichrome powder (PX20N80) was added to a 3Ti +1,2Si + 2C green mixture in the amount of 1, 5, 10 wt.% to study the microstructure and phase composition of samples and increase the operating temperature of Ti3SiC2 - based polymer coatings. Figure 1 shows the diffraction patterns of SHS products for the 3Ti-1,2Si-2С system for the initial powder X20N80 (a) and for the case when X20N80 is added to the initial mixture in the amount of 1, 5, 10 wt.% (b, c, d, i). An increase in the amount of titanium carbide is observed in the products with the additive of X20N80.

Fig.1. Diffraction patterns of SHS products for the Ti-Si-C system: X20N80 (a), 3Ti + 1,2Si+2C (b), (3Ti + 1,2Si+2C) + 1% of Х20N80 (c), (3Ti + 1,2Si+2C) + 5% of Х20N80 (d), (3Ti + 1,2Si+2C) + 10% of Х20N80 (i). Ti3SiC2 (1), TiC (2), TiSi2 (3).

Titanium carbide is the main phase for the samples with an additive of 10wt.% of X20N80. The diffractogram records the images of Ti3SiC2, as well as the images which can not be determined. There were no the images of X20N80.

The maximum combustion temperature of the 3Ti–1,2Si–2C (Ti3SiC2) composition is (2373+25) K, and the maximum combustion temperature of the initial mixture with the additive of 10wt.% of X20N80 is (2273+25) K.

Fig.2. Microstructures of SHS products for the 3Ti – 1,2Si – 2C system with the additives: 1wt.% (a), 10wt.% (b). PX20N80.

Adding PX20N80 to the green mixture leads to the decrease in the grain size of the Ti 3SiC2 phase. Adding 1% of PX20N80 to the green mixture did not demonstrate a noticeable difference in the phase composition and the microstructure as compared to the products synthesized without additives. The state diagram of the Ni-Cr system show that PX20N80 is melted, and Ni and Cr interact with the components of the initial mixture with the participation of liquid phase at the indicated temperatures. The use of composite nanolaminates, doped with nichrome, allows the operating temperature of thin- film heaters to be increased.

637 ______Functional materials and coatings

FORMATION OF THE PHASE COMPOSITION AND STRUCTURE OF ALUMOMAGNESIUM SPINEL OBTAINED BY THE SHS METHOD

N N .I. RADISHEVSKAYA , А.Yu. NAZAROVA, О.V. LVOV, N.G. KASATSKY Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634055, Russia, [email protected], +7(3822)492294

Alumomagnesium spinels were obtained using the method of self-propagating high-temperature synthesis (SHS).

The powders of aluminium oxides (Al2O3, «pure»), magnesium (MgO, «pure») and magnesium nitrate (Mg(NO3)2·6H2O, («chemically pure»)) containing aluminium (ASD-4) with amorphous boron additives were used as an initial mixture. The mixture of aluminium and boron allowed us to intensify the ignition and combustion of mixtures [1, 2]. Spinel was synthesized in metal mesh cups at atmospheric pressure in air. Ignition was initiated by an electric spiral. The development of chemical reactions was investigated using the thermogravimetric method and the Q600 thermal analyzer. The phase composition of reaction products was studied using X-ray diffraction analysis and the DRON-3M diffractometer. Structural peculiarities were studied using IR spectroscopy (Nicolet 5700 FT-IR spectrometer). The microstructure of the samples obtained was studied by optical microscopy (Axiovert 200M) and scanning electron microscopy (Philips SEM 515). The results have shown that adding amorphous boron to the initial components contributes to the

formation of low-melting В2О3 and aluminum (magnesium) borates during combustion. Aluminomagnesium spinel crystals grow in a short time during rapid SHS processes with the participation of liquid and gas phases, which leads top the formation of hollow skeletal crystals with a size from 1 μm to 10 μm. Figure 1 shows the microstructure of aluminomagnesium spinel obtained using 2 wt.% of boron as an additive. b

Fig.1. Micrograph of the products obtained by the SH- synthesis of alumomagnesium spinel (composition: M6 with 2 wt.% of boron), (a) - aggregates of large crystals, (b) - aggregates of smaller crystals, Philips SEM 515.

The products consist mainly of the MgAl2O4 phase and corundum Al2O3 in small amount. The IR- spectroscopic method demonstrates the presence of В2О3, aluminum borate, and α-BN. Alumomagnesium spinel, chemically resistant to aggressive media, has high refractory properties and can be used as structural ceramics. REFERENCES

[1] Sorokin V.A., Yanovsky L.S., Kozlov V.A., Surikov E.V. et al. // Solid or pasty propellant ram rockets. M.: Fizmatlit, 2010. [2] Kislyi P.S., Neronov V.A., Prikhna T.A., Bevza Yu.V. // Aluminum borides. Kiev: Naukova Dumka, 1990.

638 ______Functional materials and coatings

SYNTHESIS OF IRON-CONTAINING SPINEL-TYPE PIGMENTS

A.Yu. NAZAROVA, N.I. RADISHEVSKAYA Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634055, Russia, [email protected], +7(3822)492294

Compounds based on transition elements are used as chromophores to obtain spinel-type pigments. Iron oxide Fe2O3 has the greatest effect on colority among the iron triad elements. A variety of color is achieved not only by the different degree of iron oxidation - (2+, 3+), but also by easy mutual conversion of iron oxides into each other due to the redistribution of ions between octahedral and tetrahedral hollows in the structure without significant changes. The different color pigments (blue-green and dark brown) were obtained during the synthesis of pigments, using Fe2O3 oxides from different manufacturers, when the component composition of a green mixture consisting of Fe2O3, Со2O3, Cr2O3, Al2O3 and Al was constant and the other parameters of synthesis (diameter, density, etc.) were varied. The spectra of images are shown in Fig. 1.

45 2

, % 35 1 30

25 Отражение 20

10 300 400 500 600 700 800 900 λ, нм

Fig. 1. Image spectra of СоO-Cr2O3-Fe2O3-Al2O3 pigments, where 1 is the dark brown pigment (initial Fe2O3, "ARD"), 2 is the blue- green pigment (initial Fe2O3, "ACS"), Evolution-600 . X-ray diffraction analysis (DRON-UM1 diffractometer with filtered Co kα radiation) showed that the blue-green pigment СоO-Cr2O3-Fe2O3-Al2O3 contained hercinite FeAl2O4 as the main phase and the large amount of СоСr2O4 and СоAl2O4. Fe3O4 oxide is the main phase in the composition of black pigment. According to IR spectroscopic analysis (Nicolet 5700 FT-IR spectrometer), there is the bond stretch of tetrahedrally (Fe2+, Co2+) and octahedrally (Al3+, Cr3+) coordinated cations for 647 cm-1 and 543.6 cm-1 in a blue-green pigment (from Fe2O3 "ACS") consisting of a solid solution between alumospinels and chromospinels, which is typical for the structure of normal spinels. IR spectrum of the dark brown pigment -1 synthesized from Fe2O3 "ARD" demonstrates additional absorption bands in the range of 400÷850 cm , which indicates that the pigment has a structure of a mixed spinel [1]. According to X-ray diffraction analysis, initial oxide Fe2O3 "ARD" contains magnetite Fe3O4 as an impurity along with the main phase of α-Fe2O3. The quantitative analysis carried out using the Match program and the PDF-2 database showed that the amount of Fe3O4 magnetite was ~ 12 wt% in the initial Fe2O3 "ARD" and the remaining part was α-Fe2O3. Initial oxide Fe2O3 "ACS" contains not only Fe3O4 at the noise level but also lepidocrocite γ-FeO(OH). Water released during heating due to dehydration of iron oxide, in contact with aluminum contained in the green mixture, forms hydrogen that creates conditions for the SH synthesis of pigments, which contributes to the formation of hercinite. Magnetite in initial iron oxide Fe2O3 "ARD" acts as seed particles which are used for crystallization of Fe3O4, which contributes to the obtaining of dark brown and black SHS pigments.

REFERENCES 1. Barabanov V.F .// Modern physical methods in geochemistry.- L.: LSU, 1990.

639 ______Functional materials and coatings

EFFECT OF TIN OXIDES ON THE PHASE COMPOSITION AND STRUCTURE OF

СOО-AL2O 3-SNO 2 AND NIO-AL2O 3-SNO 2 SPINELS OBTAINED BY SHS METHOD

О.V. LVOV, N.I. RADISHEVSKAYA Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., Tomsk, 634055, Russia, [email protected] , +7(3822)492294

Spinels are a traditional material for the production of ceramic pigments with a wide range of colors. Sky-blue pigment (ceruleum) is known to contain tin dioxide, cobalt aluminate (blue cobalt), as well as

magnesium and zinc oxides. Therefore, in the work, SnO2 tin oxide is added as an additive that influences on the color of pigment. Pure color pigments were obtained by the SHS method under the air atmosphere in the

MgO-СоО-SnO2-Al 2O 3 system from MgO, Al2O 3, Co2O 3, SnO2 oxides and aluminum powder (ASD-4). The thermogravimetric analysis conducted using a SDT Q600 thermal analyzer showed that the oxidation of aluminum proceeded through stages:

SnO2+4Al+2O 2=Sn+2Al 2O 3 (1), CoO+2Al+O2=Co+Al 2O 3 (2), 4Al+3O2=2Al 2O 3 (3) The green mixture is heated during these reactions before starting the synthesis of spinels.

СoO+Al2O 3=CoAl 2O 4 (4), MgO+ Al2O 3=MgAl 2O 4 (5), 2CoO+SnO2=Co 2SnO 4 (6) The increase in mass after ~ 1100°C is connected with oxidation of tin.

2Sn+O2=2SnO (7), 2SnO+O2=2SnO 2 (8) Tin and its oxide SnO are strong reducing agents, which leads to the formation of a large number of cobalt inclusions in the product during synthesis. X-ray diffraction analysis (DRON-UM1 diffractometer with filtered Co kα radiation) of

MgO-СоО-SnO2-Al 2O 3 pigment showed that the products contained corundum and the large amount of cobalt along with the spinel phases. The study of the pigment section showed that the main phases were a mixture of cobalt and magnesium

aluminospinels, and there were also the blue inclusions of Co2SnO 4. In addition, particles of Со3Sn 2 intermetallide were detected, which was confirmed by micro-X-ray spectral analysis (Camebax) (Fig. 1).

Fig.1. Micrograph of MgO-СоО-SnO2-Al2O3 pigment, Axiovert 200M, where 1 is (Co, Mg)Al2O4, 2 is Co2SnO4, 3 is Co.

IR spectroscopic analysis (Nicolet 5700 FT-IR spectrometer) showed that MgO-СоО-SnO2-Al 2O 3 pigment had absorption bands typical for the spinel structure.

Spinel-type pigment synthesized by the SHS method in the MgO-СоО-SnO2-Al 2O 3 system has a bright blue color; however, a large amount of the formed metal phase significantly degrades its quality.

640 ______Functional materials and coatings

FORMATION OF THE OXIDE COATING ON THE TITANIUM SURFACE BY MULTIPULSE FEMTOSECOND LASER IRRADIATION1

M. V. ZHIDKOV *, E. V. GOLOSOV **, T. N. VERSHININA*, S. I. KUDRYASHOV***, YU. R. KOLOBOV *, **, A. E. LIGACHEV**** *Belgorod State National Research University, Pobedy street 85, 308015, Belgorod, Russia; e-mail: [email protected] **Institute of Problems of Chemical Physics, RAS, Academician Semenov avenue 1, 142432, Chernogolovka, Russia ***P.N. Lebedev Physical Institute, RAS, Leninskiy prospekt 53, 119991, Moscow, Russia ****A.M. Prokhorov General Physics Institute, RAS, Vavilov str. 38, Moscow, 119991, Russia

In our experiments commercially pure titanium VT1–0 with submicrocrystalline structure was used. The femtosecond laser irradiation (FLI) was performed in air using Ti-sapphire laser with a wavelength of 1030 nm and a pulse width of 300 fs at a rate f = 250 kHz and pulse (maximal) energy of 6 μJ. The study of the modified surface of the laser irradiated sample was carried out using a FEI Helios 660 scanning electron- ion microscope and a FEI Quanta 600 scanning electron microscope with field emission. The X-ray diffraction (XRD) studies were performed using a Rigaku SmartLab X-ray diffractometer with the Cu-Kα radiation in a Bragg–Brentano focusing mode. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies of the subsurface structure of the irradiated sample were carried out by using a field-enhanced emission microscope Tecnai G2 F20.

Fig.1. The surface oxide layer formed on titanium by femtosecond laser irradiation. SEM. The influence of FLI on the formation of an oxide layer on the surface of VT1-0 titanium alloy is studied. It is found that under FLI of the surface of the titanium alloy VT1–0 the microporous nanocrystalline coating with the thickness of ~ 50 μm is formed. According to X-ray diffraction and transmission electron microscopy, this coating consists of titanium oxides: TiO2 (rutile and anatase), TiO and Ti3O5.

1 This work was supported by the Ministry of Education and Science of the Russian Federation in the framework of the project no. 3.3144.2017/ПЧ

641 ______Functional materials and coatings

MICROSPHERES BASED ON GOLD WASTE IN STREAM HIGH-TEMPERATURE GAS1

V.V. SHEKHOVTSOV, O.G. VOLOKITIN, G.G. VOLOKITIN, N.K. SKRIPNIKOVA Tomsk State University of Architecture and Building, Tomsk, 634003, Russia, [email protected], +7-913-872-27-77

This paper presents the investigation results on a possible use of ash-based raw material for the silica- alumina microsphere production through the plasma processing. The formation of ash-based microspheres can be considered as the silicate formation process, because the obtained particles represent hollow droplets of the silicate melt. The main parameters of plasma-assisted powder processing include the temperature and the rate of plasma flow. The distribution of temperature fields and rates in plasma flow is rather complex [1]. In our experiment, we use the electro-plasma installation designed at the Department of Applied Mechanics and Materials Science (TSUAB) to produce microspheres based on refractory oxides and silicates. This installation comprises plasma generator (cathode), hollow graphite electrode and a chamber for collection of the processed material [2-5]. As a result of our experiments, we obtain microspheres with 0.4÷0.6 g/сm 3 bulk density and 90÷120 µm particle diameter. The decrease in the bulk density occurs due to the increase in the relative amount of absorbed air inside a particle occurred during the high-temperature heating. The reduction in the particle size is connected with the growth in the degree of density between the particles caused by melting of agglomerated fine particles. The XPS investigation allows obtaining the distribution maps for the elemental composition of the microsphere surface and detecting the element concentration. The plasma processing homogenizes the particles. The elements distribute uniformly over the particle surface. The plasma processing has a positive effect on the particle morphology, i.e. they acquire a spherical shape and have no surficial defects.

Fig. 1. SEM image of ash-based microspheres obtained by plasma Fig. 2. Qualitative surface distribution of chemical processing. Enlarged view contains the fragment of the elements elements after plasma processing distribution area. Summing up the results, it can be concluded that microspheres can be obtained from the bottom ash waste (Belovo Power Plant, Kemerovo region) processed by plasma energy. The designed electro-plasma installation was used to produce microspheres from agglomerated powders based on the bottom ash waste. The X-ray photoelectron spectroscopy allowed obtaining the distribution maps for the elemental composition of the microsphere surface and detecting the element concentration. REFERENCES [1] Solonenko O P, Gulyaev I P, Smirnov A V // Therm. Sci. Tech . - 2011. - 2. - No 6. 219 - 234. [2] Shekhovtsov V V, Volokitin O G, Kondratyuk A A, Vitske R E // IOP Conf. Series: Mater. Sci. Eng. - 2016. - 156. [3] Shekhovtsov V V, Volokitin G G, Skripnikova N K, Volokitin О G, Gafarov R // AIP Conf. Proc. - 2017. - 1800. - No 1. [4] Shekhovtsov V. et al. // Materials Science Forum. - 2017. - 906. 131 - 136. [5] Vlasov V A, Volokitin O G, Volokitin G G, Skripnikova N K, Shekhovtsov V V // Engineering Physics and Thermophysics. - 2016. - 89. - No 1. 152 - 156.

1 The work was supported by the state task of the Ministry of Education and Science of the Russian Federation (project number 11.8207.2017 / 8.9), a grant from the President of the Russian Federation (MD-553.2018.8) and a Presidential scholarship (SP-313.2018.1).

642 ______Functional materials and coatings

USE OF MECHANOCHEMICAL ACTIVATION FOR THE SYNTHESIS OF GARNET-TYPE PIGMENTS

N N . G . KASATSKY , А.YU. NAZAROVA, О.V. LVOV, N.I. RADISHEVSKAYA Tomsk Scientific Center SB RAS, 10/4 Akademicheskii Pr., 634055, Tomsk, Russia, [email protected], +7(3822)492294

Materials based on composite oxides with a structure of garnet attract close attention of researchers due to unique functional properties and the possibility of using in various fields of science and engineering [1-3]. Green and dark turquoise pigments were obtained from cheap row materials of the Siberian region, 2+ 3+ (uvarovite garnet, Сa3 Cr2 (SiO4)3 by the method of high-temperature solid-phase synthesis with the use of mechanical activation. Sand of a local quarry, chalk (CaCO3), and chromium oxide (Сr2O3) were used as initial components. A green mixture was milled in a MVF/4-TH ball mill with a rotation rate of 4 dm 3 porcelain drums of 60 rpm. The mass of components was 0.5 kg, the mass ratio between the balls and the mixture was 5:1, and the diameter of the balls was 20 mm. Synthesis was conducted in an EXSP-50 furnace at different temperatures with a different holding time. The synthesis products were studied using the X-ray diffraction analysis and the DRON-UM1 diffractometer with filtered Co kα radiation. The results have shown that the pigment has a complex composition and includes uvarovite garnet (Ca3Cr2(SiO4)3) as the main phase and an insignificant amount of impurities such as triple oxide (calcium chromosilicate, СaСrSi4O10) and quartz (SiO2). Figure 1 shows the microstructure of a garnet-type pigment.

Fig. 1. Microstructure of a garnet-type pigment (uvarovite) synthesized from sand of the Tomsk quarry, Philips SEM 515 (Netherlands).

As can be seen, the pigment has a fine-grained structure with a grain size of ~ 1 μm. The increase in the mechanoactivation time of the green mixture considerably increases the content of Ca 3Cr2(SiO4)3 in the pigment obtained. The optimal compositions and the modes for the synthesis of green pigments were selected in this work. This method of synthesis is promising, since it allows cheap pigments to be obtained using local mineral raw materials. Garnet-type pigments are resistant to the temperatures of up to 1300 °C and can be used as the components of acrylic and water-based paints, protective and decorative coatings, ceramic paints and for 3D- printing.

REFERENCES [1] Maslennikova G.N., Pishch I.V. / Ceramic pigments. M.: Stroymaterialy, 2009. [2] Zinchuk A. // Green ceramic garnet-type pigments based on granulated blast-furnace slag // Proceedings of the University of Ruse. -2013. -V. 52.- No. 10(1).- P.78-82. [3] Fedorov P.P., Maslov V.A., Usachev V.A., Kononenko N.E. // Synthesis of laser ceramics based on nanodispersed powders of aluminium-yttrium garnet Y3Al5O12 // Herald of the Bauman Moscow State Technical University. Series Natural Sciences.- 2012.- P.28-44.

643 ______Functional materials and coatings

INVESTIGATION OF THE INFLUENCE OF THE CONFINEMENT EFFECT ON THE YIELD OF LUMINESCENCE IN QUANTUM DOTS OF CDSE AND CDTE

D.H. DAURENBEKOV, T.N. NURAKHMETOV, B.M.SADYKOVA*, ZH.M. SALIKHODZHA, A.M. ZHUNUSBEKOV, A.ZH. KAINARBAY , K.B.ZHANYLYSOV L.N. Gumilyov Eurasian national university, 13, Kazhymukana street, Astana, 010000, Kazakhstan, [email protected], +77172709500 In CdSe and CdTe quantum dots (QDs), the width of the forbidden band increases with decreasing size and discrete energy levels appear at the edge of the bands. We note that the energy difference between the edges of the energy levels increases with size decreasing. As a consequence of quantum confinement, the width of the forbidden band of a semiconductor nanocrystal (NCs) becomes larger with decreasing size, and for dimensionality D-2 we can neglected by the Coulomb interaction. Also, discrete energy levels (with different quantum numbers) appear at the edges of both the conduction band and the valence band. In practice, this means that the optical width of the forbidden band of QDs can be controlled by simply changing their size. It is important to note that the Bohr radius of the exciton a0 provides a very effective relationship with the estimation of the effect of quantization on the properties of a semiconductor in a QD. As mentioned above, confinement begins to affect the wave function of the exciton, when the QD size approaches a0. This means that the manifestation of the quantum confinement effect will occur for different sizes of QDs for different semiconductors, since the Bohr`s radius of the exciton a0 varies widely due to the high variability of semiconductor materials. It should be noted that a0 and the width of the band gap Eg correlate, so that materials with narrower Eg have large a0 (for example, Eg and a0 for PbSe 0.26 eV and 46 nm, 1.75 eV and 4.9 nm for CdSe and 3.7 eV and 1.5 nm for ZnS) and thus, significant quantum confinement occurs at large nanostructure sizes. The dependence of the energy yield of the luminescence on the wavelength of the exciting light obeys Vavilov's law. According to which the energy output initially increases in proportion to λexc, then it remains constant and after reaching a certain boundary wavelength, it falls off sharply. There is a proportionality of the energy yield of the luminescence to the wavelength of the absorbed light, which means that the quantum yield of the luminescence in a certain spectral interval is constant. But as we know for QDs, when the size changes, the spectral position of the luminescence shifts to the form of the quantum-size effect. Since a particular spectral interval is always investigated, the relationship between the quantum-size effect and the yield of luminescence is revealed. The question of the influence of confinement effect on the yield of luminescence remains open. To a greater extent this process is not studied. The study is in the field of increasing the yield of luminescence in the NCs, and the relationship of processes is not described. In this paper we investigate the influence of the quantum-size effect on the yield of luminescence in the QDs CdSe and CdTe. The optimum QDs size of CdSe, CdTe is established to obtain the largest quantum yield of luminescence.

644 ______Functional materials and coatings

SEMICONDUCTOR QUANTUM DOTS DOWNCONVERTERS FOR SILICON SOLAR CELLS

A.Z.KAINARBAY, D.H. DAURENBEKOV, B.ABDRAMAN, T.N. NURAKHMETOV, Z.M.SALIKHODJA, A.M.ZHUNUSBEKOV, B.M. SADYKOVA, B.N. YUSSUPBEKOVA, A.KAYNARBAEVA* L.N. Gumilyov Eurasian national university, 13, Kazhymukanastreet, Astana, 010000, Kazakhstan, [email protected], *Abai Kazakh national pedagogical university, 13, Dostykave., Almaty, 050010, Kazakhstan

The combination of solar cells (SC) with luminescent “down converters” based on colloidal quantum dots (CQD) have been suggested as a very promising method to high power conversion efficiencies. For “down-conversion”, the luminescent converter (LC) as like thin film contains CQD is located on the front surface of the SC. High-energy photons with energy more than Eg are absorbed by the converter and down-converted into lower energy photons which, in turn, can be absorbed by the solar cell. In this work, we investigate the use of CQD (PbS, PbS-CdS, CdSe-CdS-ZnS, CdTe) into photovoltaic technology to increase of efficiency of silicon SC. Conventional silicon SC only effectively converts photons of energy close to the Si band gap as a result of the mismatch between the incident solar spectrum and the spectral absorption properties of the material. This loss can be reduced by using photoluminescence, where by photons are shifted into an energy range where the cell has a higher spectral response. CQD were proposed for use as down-shifters because the emission wavelength can be tuned by their size, as a result of quantum confinement. In order to analyze the effect of the LC we performed a series of optical and PV measurements. The LC or thin layers were characterized using PL measurements to verify the CQD formation and quantify their light emission. There is a high PL emission with a peak at 627 nm(CdSe/ZnS), 761 nm (CdTe), 875 nm(PbS/CdSe), respectively. Figure 1 showed spectra of diffuse reflectance of SC(1), luminescence spectrum of CdSe/ZnS(2), CdTe(3), PbS/CdS(4).

Fig.1. Spectra of diffuse reflectance of SC(1), luminescence spectra of QCD CdSe/ZnS(2), CdTe(3), PbS/CdS(4). PV measurements were performed at standart condition, 25 0C, AM1.5 irradiation to extract the power conversion and quantum efficiency of the solar cells. These measurements showed an increase of efficiency of coated SC. We showed that CQD are efficient down-shifters for photovoltaic applications. An enhancement of the quantum efficiency of about 4-8% was demonstrated in 200-1100 nm optical range. Further work is required to optimize the QCD down-shifter in order to increase the overall power conversion efficiency of the solar cell. Using QCD with high QY can potentially increase the efficiency of SC to 20%. Also the QCD down-shifter will play also the role of an antireflection coating, and the reflection losses will be reduced. Therefore, the combination of antireflection coating and down conversion leads to increasing the efficiency SC.

645 ______Functional materials and coatings

SHIELDS OF LOCAL PROTECTION FOR SEMICONDUCTOR DEVICES AGAINST OUTER SPACE ELECTRON RADIATION

D.I. TISHKEVICH*, S.S. GRABCHIKOV*, S.B. LASTOVSKII*, D.S. VASIN**, A.S. YAKUSHEVICH*, A.V. TRUKHANOV* *SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, Minsk, 220072, Belarus, [email protected], +375295628187 **Belarusian State University of Informatics and Radioelectronics, P. Brovki str., 6, Minsk, 220013, Belarus

Nowadays, the maintenance of high indicators of devices and equipment operational reliability in the raised level of radiation influence conditions (electrons, protons, heavy charged particles, X-ray and gamma radiation) is very actual. Currently, the problem of radiation resistance increasing is solved by several methods: technological (specialized technological processes and materials), constructive (specialized packages, methods of local protection), schematics (majorization methods, etc.) and method for radiation defects modeling of integrated microcircuits at the design stage. The widely used material for radiation protection is lead, but it is a toxic material with a high density and a low melting point value. In this regard, the problem of replacing lead with other more environmentally friendly and effective materials in terms of its mass-dimension parameters is very relevant. 2 Samples of shields based on W77,5Cu22,5 composite in the form of plates with 20×20 mm size and 0.6, 0.9, 1.2 and 1.5 mm thicknesses were obtained by solid-phase synthesis method. Samples radiation using a linear electron accelerator ELA-4 was carried out. A duralumin plate of 5 mm thickness was placed between the target and the electron output window to approximate the accelerator ELA-4 electron spectrum characteristics to the spectrum of electrons of the Earth's radiation belt (Ee=1.6-1.8 MeV). The shielding efficiency was evaluated by estimating the behavior of the volt-ampere characteristics (VAC) of test n- and p-MOS transistors (MOST). The shielding efficiency coefficient values (the attenuation coefficient) (Ka) were simulated from ratio (1) Кa = F/F0, (1) Where F – the electron fluence corresponding to a parametric failure of a shielded test MOST; F0 – the electron fluence corresponding to a parametric failure of unshielded test MOST. The parametric failure of MOST was fixed with threshold voltage changing ΔU = 0.1 V. The results of protected and unprotected n- and p-MOST by shields under electron irradiation with 1.8 MeV energy in the passive electric mode, are shown in Figure 1. For all test MOST, ΔU growth in the whole electron radiation fluences investigated range is observed. However, the same ΔU values of protected and unprotected n-MOST are obtained in case of protected n-MOST, but with radiation fluences in two orders higher than for the case of unprotected n-MOST. The use of protective shields in hundred times or more reduce the speed of p-MOST parameters degradation under electrons irradiation. Data analysis shows that the excessive thickness build-up of the W77.5Cu22.5 shields does not give a clear advantage in the radiation protective properties of shields. Apparently, this is due to the presence of braking radiation, which has a greater penetrating power. In this connection and, proceeding from the requirements of minimization of mass-dimension parameters, the most optimal thicknesses of W77.5Cu22.5 shields are 0,9÷1,2 mm values.

Fig. 1. Dependences of the n- (a) and p-MOST (b) voltage variation on the electron radiation fluences without and with shields with different thicknesses.

646 ______Functional materials and coatings

CREATION OF HIGHLY DISPERSE METALS ON A CARBON SUBSTRATE T.A. UDALOVA* ,**, E. T. DEVYATKINA*, S. V. VOSMERIKOV* , T. F. GRIGOREVA*, N. Z. LYAKHOV* *Institute of Solid State Chemistry and Mechanochemistry of Siberian Branch of Russian Academy of Sciences, 18 Kutateladze str., Novosibirsk, 630128, Russia, [email protected], 8-952-922-56-45 **Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russia

a b Fig. 1. Electron micrographspurified mechanocomposites Ag/C (a), magnification: a – 5000. X-ray diffraction (b) mechanocomposites Ag/C and AgNO3.

The work was carried out within the framework of the state assignment of the IHTTM SB RAS (project 0301- 2018-0001).

647 ______Functional materials and coatings

ON CRYSTALLIZATION OF A METAL MELT INOCULATED WITH NANOPARTICLES 1

A.N CHEREPANOV*, V.K. CHEREPANOVA*, **, V. MANOLOV*** AND L. YOVKOV*** *Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, 4/1 Institutskaya st., Novosibirsk, 630090, Russia, [email protected], +7(913)8976924 **Novosibirsk State Technical University, 20 K. Marx av., Novosibirsk, 630073, Russia ***Institute of Metal Science, Equipment and Technologies “Acad. A. Balevski” with Hydro- and Aerodynamics Centre, Bulgarian Academy of Sciences, 67 Shipchensky Prohod st., Sofia, 1574, Bulgaria

To obtain a fine and uniform grain structure upon solidification of metals and alloys, it is possible to use particle-nucleants which are specially introduced into the melt or, in other words, inoculated. On such particle heterogeneous nucleation will occur the course of which depends on the shape of the substrate, its wettability, dimensions and conjugation of atomic lattices of the substrate and the nucleus [1-3]. To understand the mechanisms of structure formation during solidification of inoculated metals and alloys, it is necessary to study the features of nucleation of crystallization centers on activated nanoparticles, depending on their dimensional, morphological and capillary properties. In the present work the process of crystallization of a binary alloy modified by refractory wettable nanoparticles. A small volume of the melt is chosen for the study and its internal thermal resistance is negligible compared to the external ones. In this case the temperature distribution in the volume can be considered homogeneous and the rate of its cooling is given. This alloy contains highly activated wettable refractory nanoparticles. As follows from the results of work [4], homogeneous nucleation in the process of solidification of such a melt is practically not observed, and the nucleation and growth of the crystalline phase occurs only on seeds, so homogeneous nucleation is not taken into account here. In this paper, a mathematical model of the nucleation and growth of a solid phase in a nanomodified alloy with a eutectic-type phase diagram proposed earlier in [5] is developed. Here is a kinetic equation for describing the crystallization of a binary system of a eutectic composition after cooling the melt to the eutectic temperature. As a result, we obtained analytical expressions for the formation energy and the rate of nucleation of crystallization centers on cubic nanoseeds (nanoparticles), taking into account the dimensional and capillary effects. Equations are proposed for describing the macroscopic growth of the primary phase during the continuous cooling of the binary alloy to the eutectic temperature and the growth of the fraction of the solidified eutectic with further cooling of the alloy. To verify the mathematical model, a comparison is made with an experimental study of the crystallization process of an aluminum alloy in a cylindrical form. During the solidification of the sample, its temperature was recorded, for this purpose a high-speed thermocouple was located in its center. The experimental and calculated values coincided with a sufficiently high degree of accuracy, the error is of the order of 1%.This indicates that the proposed model satisfactorily describes the actual physical process of crystallization of the inoculated alloy with the adopted values of the kinetic growth constants and the wetting angle. Based on the results of numerical experiments, the value of the maximum supercooling of the melt, the maximum nucleation rate and the characteristic grain size of the ingot were estimated. As follows from the calculations performed, an increase in the number of seeds themselves leads to an insignificant (~ 5%) decrease in grain size by an order of magnitude. The greatest influence is exerted by the wetting angle of nanoseed surface by the nucleus substance. This causes the need to clad substrate surfaces with metals. REFERENCES [1] Fletcher N.H. // J. Chem. Phys.– 1958. – Volume29. – №3. Pages 572–576. [2] Maxwell I., Hellawell A. // Acta Metallurgica. – 1975. – Volume 23. Pages 229−237. [3] Turnbull D. // J Chem. Phys – 1950. – Volume 18. Pages 198–205. [4] Cherepanov A.N., Popov V.N., Solonenko O.P. // J. Appl. Mech. and Tech. Phys. – 2006. – Volume 47. Pages. 22–26. [5] Cherepanov A.N., Cherepanova V.K., Manolov V. // AIP Conference Proceedings. – 2017. – Volume 1893. Art. 030114 (7 p.).

1 This work was supported by the RFBR, grant 18-08-00571 and National Science Fund of Bulgaria, Project DN07/20/15 DEC 2016.

648 ______Functional materials and coatings

COMPARATIVE STUDY OF PLASMA INFLUENCE AND STERILIZATION EFFECT ON THE POLYLACTIC ACID FILMS SURFACE PROPERTIES

E.O. FILIPPOVA, N.M. IVANOVA, V.F. PICHUGIN Tomsk Polytechnic University, Lenin str. 30, Tomsk, 634050, Russia, [email protected], +79132856796

Polylactic acid is bioactive and biodegradable thermoplastic aliphatic polyester widely used in medicine. There are a lot of medical devices based on polylactic acid such as suture materials, bone plates, abdominal nets, stents, scaffolds for tissue regeneration, and drug delivery systems with controlled degradation [1]. Using the polylactic acid as an implant for ophthalmology particularly for bullous keratopathy treatment [2, 3] is the perspective direction for creating implants of new type. In view of the fact that the virgin surface of polylactic acid has a nonwettable surface we need to treat the material for creating desired properties. All medical implants should be sterilized before operation. The requirements to methods of polymeric material sterilization are very strict due to the need to preserve the shape of the graft and material properties. Sterilization by steam (moist heat) and γ-irradiation are widely spread in the medicine practice. Steam sterilization and effect of γ-irradiation can change physical and chemical properties of materials and can be cause of its destruction. The aim of this research is the comparative study of plasma influence and sterilization effect on the polylactic acid films surface properties. Materials and methods. The polylactic acid films of 25-30 μm thickness was made by dissolution of polylactic acid in СHСl3. After films preparation the materials surface was treated by low-temperature plasma. The barrier discharge of plasma was carried out using cold plasma source. Low-temperature plasma had 25 kV voltages, 5 kHz frequency, 2 W/cm2 of the power density. The temperature of treated surface did not exceed 40°C. Plasma treatment time was 30, 60 and 90 seconds. The sterilization was carried out in two ways. The first mode was steam sterilization (temperature was 120°С, pressure was 0.11 MPa). The second one was γ-irradiation of Co60 radionuclide with 1 kGy dose. The surface properties were studied using laser scanning microscopy and atomic force microscopy. Results showed that the virgin films have roughness parameters: Ra 0.27 - 0.333 μm, Rq 0.4-0.42 μm, Rt 2.2-2.5 μm, Rv 1.23-1.4 μm, Rz 1.65-1.9 μm. The polylactic acid films had two different surfaces: more smoothing (Ra 0.27 μm) and more rough (Ra 0.333 μm), which is associated with the manufacture of these films. The plasma treatment and γ-irradiation of Co60 decreased roughness parameters by a factor of 1.3. This effect was explained by the free radicals formation on the polymer’s surface and surface smoothing after low-temperature plasma treatment. Steam sterilization decreased roughness parameters by a factor of 2.6, which is associated with deformation the thin polymer’s film after heating and pressure influence.

REFERENCES [1] Lopes M. S., Jardini A. L., Maciel Filho R. // Procedia Engineering.  2012.  Vol. 42.  PP. 1402-1413. [2] E.O. Filippova, V.V .Sokhoreva, V.F. Pichugin // Petroleum Chemistry.  2014.  Vol. 54. PP. 669-672. [3] E.O. Filippova, D.A. Karpov, A.V. Gradoboev, V.V. Sohoreva, V.F. Pichugin // Inorganic Materials: Applied Research.  2016.  Vol. 7.  №. 5. – PP. 484 – 492.

649 ______Functional materials and coatings

EFFECT OF PRECURSOR FLOW RATE ON PHYSICAL AND MECHANICAL PROPERTIES OF 1 a-C:H:SIOX FILMS DEPOSITED BY PACVD METHOD

A.S. GRENADYOROV, K.V. OSKOMOV, A.A. SOLOVYEV Institute of High Current Electronics SB RAS, 2/3 Akademichesky Ave., Tomsk, 634055, Russia, [email protected], +7-3822-491- 651

Amorphous silicon-carbon (a-C:H:SiOx) films have recently attracted considerable attention due to their wide range of technological uses. Typically, such films consist of two interpenetrating structures - diamond- like a-C:H and SiOx, which makes them a new class of diamond-like materials [1, 2]. a-C:H:SiOx films have attracted large interest mainly because of their unusual mechanical, tribological, optical, and electrical properties, comparable with the characteristics of diamond like coatings [3-6]. One of the main advantages of a-C:H:SiOx films are low internal stresses (less than 1 GPa), which allow forming films with a thickness of a few tens of micrometers with good adhesion [7]. The most common method for the formation of a-C:H:SiOx films is PACVD with RF bias voltage. However the deposition on large area substrates makes the industrial application of RF PACVD processes difficult. From this point of view it is more advantageous to use impulse bipolar plasma technologies, because they allow working at higher power, compared to RF discharge and without matching networks. The present work is devoted to the study of the effect of precursor (polyphenylmethylsiloxane, PPMS) flow rate on the physical and mechanical properties of a-C:H:SiOx films formed by plasma-chemical deposition using the bipolar bias voltage applied to the substrate. The deposition method is described in detail in [8]. Deposition of a-C:H:SiOx films was carried out on single-crystal silicon substrates. The surface morphology of the obtained films was studied using atomic force microscopy; the semi-quantitative ratio of sp3- and sp2-hybridized carbon atoms in the film was determined by Raman spectroscopy and FTIR spectroscopy. It is shown that an increase in the PPMS flow rate from 35 to 287 μl/min leads to an increase in the film growth rate from 17 to 220 nm/min, while the hardness of the obtained films varies slightly and is 14±0.8 GPa. The elastic recovery of thin films under a normal load applied during nanoindentation is evaluated and it is equal to 90-96% at a load of 2 mN, and 71-75% at a load of 20 mN. Using a-C:H:SiOx film on the stainless steel substrate and on the substrate made of VT1-0 titanium alloy allowed to reduce the friction coefficient from 0.55 to 0.095 and from 0.37 to 0.097, respectively. At the same time, the wear rate decreased from 0.6·10-3 to 4.9·10-6 mm3/N·m and from 1.3·10-3 to 6.6·10-6 mm3/N·m, respectively.

REFERENCES [1] Dorfman V.F. // Thin Solid Films. – 1992. – V. 212. – P. 267-273. [2] Dorfman V.F., Bozhko A., Pypkin B.N. et al. // Thin Solid Films. – 1992. – V. 212. – P. 274-281. [3] Randeniya L.K., Bendavis A., Martin P.J. et al. // Diamond & Related Materials. – 2009. – V. 18. – P. 1167-1173. [4] Damasceno J.C., Camargo Jr. S.S. // Thin Solid Films. – 2008. – V. 516. – P. 1890-1897. [5] Neerinck D. // Diamond & Related Materials. – 1998. – V. 7. – P. 468-471. [6] Yang W.J., Sekino T., Shim K.B. et al. // Surface and Coatings Technology. – 2005. – V. 194. – P. 128-135. [7] Batory D., Jedrzejczak A., Szymanski W. et al. // Thin Solid Films. – 2015. – V. 590. – P. 299-305. [8] Grenadyorov A.S., Oskomov K.V., Solov’ev A.A., Rabotkin S.V. // Technical Physics. – 2016. – V. 61(5). – P. 690-695.

1 This work was supported by Government task of Institute of High Current Electronics № 0366-2016-0010

650 ______Functional materials and coatings

ELECTRON BEAM SURFACE ALLOYING OF CARBON STEEL BY ALUMINUM FOLLOWED BY MICRO-ARC OXIDATION

E.V. YAKOVLEV, A.B. MARKOV, V.I. PETROV Institute of High Current Electronics SB RAS, 2/3 Akademichesky Avenue, Tomsk, 634055, Russia, [email protected]

It is well known that micro-arc oxidation (MAO) technology is widely used for growing ceramic-like coatings with high hardness, good corrosion, and wear resistance. The MAO is considered as an advanced form of anodic oxidation and primarily applied to valve metals such as aluminum, magnesium, titanium, zirconium and their alloys [1, 2]. These valve metals set as anodes are directly oxidized to form the hard and compact ceramic coatings of Al2O3, MgO, TiO2, andZrO2 oxides during plasma electrolytic oxidation. But, it is difficult using conventional MAO method to obtain a thick compact coating on a non-valve metal, iron for example. Jiang and Wang grew a MAO coating on Q235 steel set as an anode in a mix solution of sodium aluminate and sodium dihydrogen phosphate [3, 4]. This MAO coating consisting FeAl2O4, Fe3O4 and γ- A12O3 phases was porous and not very compact. However, MAO coatings on steel substrates can be obtained if the aluminum high adhesion layer previously applied. Such a highly adhesive coating, or rather a surface alloy, can be obtained by surface alloying with a low-energy, high-current electron beams (LEHCEB). By alternating processes of Al thin film deposition followed by a pulsed electron-beam mixing of deposited film and a top layer of the substrate aluminum-steel surface alloy was produced. Subsequent surface alloyed steel substrate MAO coating formation was conducted. In this work aluminum-steel surface alloy was produced directly on steel substrate in vacuum by alternating processes of Al thin film deposition followed by a pulsed electron-beam mixing of deposited film and a top layer of the substrate with further formation of the MAO coating from the surface alloy. The electron-beam machine “RITM-SP” with an explosive- emission cathode and a plasma-filled diode generating the LEHCEB was employed in the work. This machine is equipped with a multi-magnetron sputtering system enabling formation of multicomponent surface alloys. The process of formation of surface alloys consists of the deposition of film on a substrate followed by a liquid-phase mixing of the deposited film and the substrate upper layer with a LEHCEB without breaking vacuum. Much attention in the work has been payed to investigation of Al-Steel surface alloy. For its characterization different techniques like SEM, XRD and others have been used. The elemental composition of both the surface and cross sections of the samples was analyzed by EDS analysis. The competitive investigation of adhesion and wear resistance properties of two types of coatings, namely, MAO coating on steel substrate after surface alloying and standard MAO coating on aluminum substrate have been fulfilled. REFERENCES [1] R.H.U. Khan, A. Yerokhin, X. Li, H. Dong, A. Matthews // Surf. Coat. Technol. – 2010. – 205. – 6. 1679-1688. [2] W. Xue, Q. Jin, Q. Zhu, M. Hua, Y. Ma // J. Alloys Compd.– 2009. – 482. – 1–2. 208-212. [3] Y. Wang, Z. Jiang, Z. Yao // Curr. Appl. Phys. – 2009. – 9. – 5. 1067-1071. [4] Y. Wang, Z. Jiang, Z. Yao, H. Tang // Surf. Coat. Technol. – 2010. – 204. – 11. 1685-1688.

651 ______Functional materials and coatings

TRANSITION LEVELS OF ACCEPTOR IMPURITIES IN ZNO CRYSTAL BY DFT-LCAO CALCULATIONS

A.B. USSEINOV1,3, YU. ZHUKOVSKII2, E.A. KOTOMIN2, A.T. AKILBEKOV1, M.V. ZDOROVETS3, G.M. BAUBEKOVA1 1L.N. Gumilyov Eurasian National University, Astana, Kazakhstan 2Institute of Solid State Physics, University of Latvia, Latvia 3Institute of Nuclear Physics, Astana, Kazakhstan

It is known that zinc oxide is a promising functional material for optoelectronics, in particular for LEDs. Today, there are many experimental and theoretical studies devoted to the study of the electronic structure of zinc oxide doped with donor and acceptor impurities [1, 2]. In particular, it became clear that the group V impurities do not play an important role in the production of the p-type semiconductor. However, here, the mechanism of conductivity of a doped crystal remains unclear, since it does not have a detailed description. The answer to the question about mechanism of influence of various impurities on conductivity has no direct experimental proofs, but is formulated from direct observations. In this connection, there arises the need for a detailed description of the electronic properties of the equilibrium crystal structure with an impurity of a certain type. We present the results of DFT-LCAO calculations of the optical transition levels for nitrogen and phosphorus elements, introduced to zinc oxide crystal. The calculations are carried out in the CRYSTAL program [3]. Errors due to spurious electrostatic interactions in the finite-sized cells were corrected using the scheme proposed by Leslie and Gillan [4] and by Makov and Payne [5]. As result we shown that nitrogen and phosphorus are rather deep acceptors than small ones with optical transition levels ε(0/-) about ~2.0 and 2.2 eV for N and P, respectively, and do not contribute to p-type conductivity of ZnO. As shown by a recent combined EPR and DFT/B3LYP study, nitrogen species indeed are rather deep acceptors, confirming the results of our calculations [6]. It has been shown that NO with the hole localized along the bond parallel to the c axis (NO||) is the most stable configuration and gives good agreement with electron paramagnetic resonance (EPR) measurements [6].This should be enough to disregard the XO (X=N, P) configurations as a possible source of p-type doping.

REFERENCES

[1] S. Lany and A. Zunger // Phys. Rev. B. – 2010. – V.81. – P. 205209. [2] Federico Gallino, Gianfranco Pacchioni, and Cristiana Di Valentin // J. Chem. Phys. – 2010. – V. 133. – P. 144512 [3] R. Dovesi, V.R. Saunders, R. Roetti, R. Orlando, C.M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N.M. Harrison, I.J. Bush, P. D'Arco and M. Llunell // CRYSTAL09 User's Manual, 2009. University of Torino, Torino. [4] M. Leslie and M. J. Gillan // J. Phys. C. – 1985. – V.18. – P. 973 [5] G. Makov and M. C. Payne // Phys. Rev. B. – 1995. – V. 51. – P. 4014 [6] F. Gallino, C. Di. Valentin, G. Pacchioni, M. Chiesa, and E. Giamello // J. Mater. Chem. – 2010. – V.20. – P. 689

652 ______Functional materials and coatings

PRODUCTION OF MATERIALS WITH ULTRAFINE STRUCTURE OF ALUMINUM ALLOY BY FRICTION STIR PROCESSING

A.V. CHUMAEVSKII*, K.N. KALASHNIKOV*, T.A. KALASHNIKOVA* *Institute of Strength Physics and Materials Sciences SB RAS, Tomsk, Akademicheskii av. 2/4, Russia

Friction stir processing is a promising and popular method for the formation of an ultrafine-grained structure on the surface of materials based on plastic deformation during frictional contact [1-9]. The processing takes place by inserting a rotating pin into the material by heating the metal in the contact area and moving the tool along the specimen. As a result, material is mixed in the zone determined by the size of the pin and the arms of the tool, which leads to grain refinement and a change in the structural-phase state. This method can produce materials with an average grain size of less than 1 μm, without affecting the internal volumes of the material. Also by this method it is possible to form volumetric ultrafine-dispersed materials. Despite the large amount of recent work on this subject, up to the present time there is little data on the formation of a material with a large machined surface area in several passes by a tool. In the present work, a study was made of the material obtained on the surface of samples of alloy D16 in steps 1, 2 and 3 of the passes with different types of instruments along the sample line. The processing of sheet rolled products of alloy D16 was carried out on a laboratory installation for friction stir welding with ISPMS SB RAS. Investigation of the distribution of secondary-phase particles was performed with a scanning electron microscope NIKKISO SM3000. The investigation of the grain structure was carried out on an optical microscope Altami MET-1C. The structural-phase state studies were carried out using a JEOL JEM-2100 transmission microscope. The carried out researches show that in carrying out multiple passes in the zone of intersection of mixing zones of the sheet metal material, a slight increase in the average size and volume fraction of the particles of stable secondary phases is observed in a number of cases. The grain size of the mixing zone also remains at 1 μm and does not undergo significant changes. On the boundaries, in triple junctions and in the bodies of grains of the α-Al solid solution, secondary phase precipitates of various dispersity and shape are deposited. The results of identification of typical microdiffraction patterns obtained during TEM studies showed that the grains of the α-Al solid solution have zone axes of the type <110> (predominantly), as well as <113> and <134>. That is, the crystallographic axes of the type [110], [113] and [134] are parallel to the processing axis. This phenomenon is also observed by the authors of other works in the field of friction, friction with mixing and rolling. The work was carried out The program of fundamental scientific research of state academies of sciences, direction III.23. REFERENCES [1] Tarasov, S.Y., Rubtsov, V.E., Kolubaev, E.A. A proposed diffusion-controlled wear mechanism of alloy steel friction stir welding (FSW) tools used on an aluminum alloy // Wear. – 2014. – Vol. 318 – pp. 130-134. [2] Tarasov, S.Y., Rubtsov, V.E., Kolubaev, E.A. The effect of friction stir welding tool wear on the weld quality of aluminum alloy AMg5M // AIP Conference Proceedings. – 2014. – Vol. 1623. – pp. 635-638. [3] Kolubaev A.V., Kolubaev E.A., Sizova O.V., Zaikina A., Rubtsov V.E., Tarasov S.Y. General Regularities of the Microstructure Formation during Friction Stir Welding and Sliding Friction // Journal of Friction and Wear. 2015; 36(2):127-131. [4] Tarasov S., Rubtsov V., Kolubaev A. Subsurface shear instability and nanostructuring of metals in sliding // Wear. Vol. 268, 2010, P. 59–66. [5] Kolubaev A., Tarasov S., Sizova O., Kolubaev E. Scale-dependent subsurface deformation of metallic materials in sliding // Tribology International. Vol. 43, 2010, P. 695–699. [6] Tarasov, S. Y. Ultrasonic-assisted aging in friction stir welding on Al-Cu-Li-Mg aluminum alloy Tarasov, S. Y., Rubtsov, V. E., Fortuna, S. V., Eliseev, A. A., Chumaevsky, A. V., Kalashnikova, T. A. & Kolubaev, E. A. Welding in the World, Le Soudage Dans Le Monde. 61, 4, 2017, Pages 679- 690 29 [7] Eliseev, A. A., Fortuna, S. V., Kolubaev, E. A. & Kalashnikova, T. A. Microstructure modification of 2024 aluminum alloy produced by friction drilling Materials Science and Engineering A. 691, 2017, Pages 121-125 5 стр. [8] S.Yu. Tarasov, A.V. Filippov, E.A. Kolubaev, T.A. Kalashnikova Adhesion transfer in sliding a steel ball against an aluminum alloy // Tribology International V. 115, P. 191–198 [9] Eliseev, A. A., Fortuna, S. V., Kalashnikova, T. A., Chumaevskii, A. V., Kolubaev, E. A. Structural phase evolution in ultrasonic-assisted friction stir welded 2195 aluminum alloy joints. Russian Physics Journal, 2017, Volume 60, Issue 6, pp 1022–1026

653 ______Functional materials and coatings

STRUCTURAL EVOLUTION OF 321 STAINLESS STEEL IN ELECTRON BEAM FREEFORM FABRICATION

A.V. CHUMAEVSKII*, S.YU. TARASOV**, A.V. FILIPPOV* *Institute of Strength Physics and Materials Sciences SB RAS, Tomsk, Akademicheskii av. 2/4, Russia **National Research Tomsk Polytechnic University, Tomsk, Lenin av. 30, Russia

Additive manufacturing is the most advancing and fast developing process for making complex near net shape and important components of air space applications. Electron beam processes have earlier been used for welding [1], coating deposition on various substrates [2-4] as well for forming wear-resistant subsurface structures [5-7]. Both vacuum-base and non- vacuum processes are used. The EBF3 process has some advantages such as high deposition rate, high deposited metal density, no oxidized layers, etc. [8]. Laboratory EBF3 equipment has been used for making samples. The EBF3 process parameters were as follows: current 33 мА, voltage 33 kV, scanning speed 200 mm/min, scanning step 0.8 mm. Stainless steel 321 grade 1 mm diameter wire was used for forming samples which then have been cut into smaller sample for microstructural examination. These sample have been mechanically ground using abrasive sand paper, then polished using first 1 mkm grit diamond paste and then colloid quartz suspension 60 nm grit. Etching has been carried out using electrochemical cell where anode was sample and cathodes were two steel plate electrodes. Solution of 10% oxalic acid was used as electrolyte. The etching voltage and current were 6.1 V and 0.05 A, respectively. Process duration 30-40 s. On etching, the samples have been examined using an optical microscope thus obtaining optical images of the sample both cross sections. Mechanical tests have been carried out using a tensile machine Testsystems 110M-10 at room temperatures. The tensile axis coincided with the sample’s building direction. Samples for mechanical tests have been EDM cut out from three different zones such as substrate, fusion line between substrate and as- clad metal and as-clad metal. Fractography studies have been performed using a scanning electron microscope NIKKISO SM3000. Metallographic studies allowed showing that as-clad metal consists of dendritic structures (Fig.1). The cross section panoramic view in Fig.1a shows a fusion line between as-clad metal and substrate as well as fusion lines between as-clad metal layers. The very first as-clad layer has the less thickness (450 mkm) as compared to that of further deposited layers which are almost equal thickness ones (800-900mkm). The latter is a evidence of the EBF3 process stability since that thickness corresponds to the vertical scanning step. The fracture surfaces of as-clad metal contains some microscopic pits which may be < 5mkm size pores (Fig.4a). Larger 20-30 mm size and numerous small 3-5 mkm pits are observed on the fracture surface of sample cut out of the as-clad/substrate fusion line zone (Fig.4b). The base metal fracture surface predominantly shows up large pits (Fig.4c). This work has been carried out with funding support from Ministry of Education and Science (agreement № 14.610.21.0013, project identification No RFMEFI61017X0013). REFERENCES [1] Klimenov V.A., Gnyusov S.F., Potekaev A.I., Klopotov A.A., Abzaev Y.A., Kurgan K.A., Marzol M.R., Galsanov S.V., Tsellermayer V.Y., Marchenko E.S. // 2017. Russian Physics Journal. 60(6), pp. 990-1000 [2] Poletika I.M., Tetyutskaya M.V., Makarov S.A. // Inorganic Materials: Applied Research Volume 6, Issue 3, 20 May 2015, Pages 249-254 [3] Poletika I.M., Ivanov, Y.F., Golkovskii, M.G., Krylova, T.A., Teresov, A.D., Makarov, S.A. // Inorganic Materials: Applied Research Volume 2, Issue 5, 2015, Pages 531-539 [4] Bataev V.A., Golkovski M.G., Samoylenko V.V., Ruktuev A.A., Polyakov I.A., Kuksanov N.K // Applied Surface Science Volume 437, 15 April 2018, Pages 181-189 [5] S.F. Gnyusov, A.A. Ignatov, V.G. Durakov, S.Yu. Tarasov // Applied Surface Science 263 (2012) 215–222 [6] S.F. Gnyusov, S.Yu. Tarasov // Surface & Coatings Technology 232 (2013) 775–783 [7] S.F. Gnyusov, S.Yu. Tarasov // Applied Surface Science 293 (2014) 318– 325 [8] Ding D., Pan Z., Cuiuri D., Li H. // The International Journal of Advanced Manufacturing Technology October 2015, Volume 81, Issue 1–4, pp 465–481

654 ______Functional materials and coatings

SYNTHESIS OF POLY(L-LACTIC ACID)-HYDROXYAPATITE COMPOSITE AS MATERIAL FOR 3D PRINTING OF BONE TISSUE GROWTH STIMULATING IMPLANTS1

G.E. DUBINENKO*, A.L. ZINOVIEV*, E.N. BOLBASOV* *Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia, [email protected], +79969387900

Synthesis of new biodegradable materials is the promising area of reconstructive and regenerative surgery development. The implant made of biodegradable material serves as a temporary scaffold in the process of new tissues growth [1]. Poly(L-lactic acid) (PLLA) is one of the most attractive materials for biodegradable implants fabrication due to its ability to degrade to non-toxic lactic acid monomers [2]. However, the poor mechanical performance restricts applying of PLLA as a material for implants [3]. Implants fabricated from the PLA are not capable to maintain their morphology under the mechanical loads and require additional fixation [4]. In this research, biological mineral hydroxyapatite (HAp) was used to obtain biodegradable PLLA-based composites with enhanced mechanical performance and bioactive properties.

Fig. 1. Elastic modulus of PLLA-HAp composite at different HAp dosages before and after crystallization Composites were produced from PLLA and biological HAp at different wt.% HAp content (0–50 wt.%). To produce PLLA-HAp filaments, composites were granulated and extruded through 1.75 mm nozzle. In addition, 100% PLLA filament was prepared for printing control samples. PLLA and PLLA-HAp filaments were used to print samples (20 mm in diameter, 2 mm in height) by using FDM 3D printing technology. Samples were divided into two groups, and then samples from one of the groups were crystallized. The results of mechanical tests show the growth of elastic modulus with an increasing amount of HAp (Fig. 1). The maximum value of 7,4 GPa elastic modulus reached after crystallization of the composite with 50 wt.% filling of HAp. Furthermore, the decrease in the samples deformation during the crystallization was observed with increasing of HAp amount. The deformation decreased from 8.3% to 1.86% with an increase of HAp amount in the polymer matrix from 12,5% to 50%. REFERENCES [1] Dietmar W. Hutmacher. Scaffolds in tissue engineering bone and cartilage // Biomaterials. – 2000. – 21. - № . 2529-2543. [2] Yuval Ramot, Moran Haim-Zada, Abraham J. Domb, Abraham Nyska. Biocompatibility and safety of PLA and its copolymers // Advanced Drug Delivery Reviews. – 2016. – 107. - № . 153-162. [3] J.M. Chacona, M.A. Caminerob, E. Garcıa-Plazab, P.J. Nunez. Additive manufacturing of PLA structures using fused deposition modelling: effect of process parameters on mechanical properties and their optimal selection // Materials and Design. – 2017. – 124. - № . 143-157. [4] F.S.Senatovn, K.V.Niaza, M.Yu.Zadorozhnyy, A.V.Maksimkin, S.D.Kaloshkin, Y.Z.Estrin. Mechanical properties and shape memory effect of 3D-printed PLA-based porous scaffolds // Journal of the Mechanical Behavior of Biomedical Materials. – 2016. – 57. - № . 139-148.

1 This work was financially supported by the Ministry of Education and Science of the Russian Federation, Federal Target Program (agreement # 14.575.21.0140, unique identifier RFMEF157517X0140).

655 ______Functional materials and coatings

NOVEL ENTROPY–STABILIZED ULTRA HIGH TEMPERATURE CERAMICS THIN FILMS PREPARED BY MAGNETRON SPUTTERING

S. DEMCHENKO*, D. ZELENTSOV,* S. LINNIK*, A. GAYDAYCHUK*, S. ZENKIN*, *Tomsk Polytechnic University, Lenin 30,Tomsk, 634034,Russia, [email protected] The entropy stabilization concept recently has been successfully applied to oxides and borides of transition metals, and induce the great interest especially in the case of ultra-high temperature application. These materials typically are a single-phase mixture of 4 or 5 elements in equiequiatomic proportions. Here we show the new thin film ceramic system (Hf1/4Zr1/4Y1/4Ce1/4) O2-δ which exhibit superior thermal stability up to 2000°C. Films were prepared by the reactive magnetron sputtering using two metallic HfZr and YCe targets in Ar+O2 atmosphere. Sputter deposition we performed at room temperature and 500°C. We show relationships between sputtering parameters such as magnetron power density, total pressure, gas mixture and properties of produced film such as mechanical properties, density, phase evolution and thermal stability. We determine the sputtering parameters “window” were sputtered films are characterized by the single-phase cubic structure. We use thermogravimetry measurements in order to characterize thermal properties of studied films. Also we have studied the role of the fifth element addition with different crystal structure (MgO) on the entropic stabilization of the coatings.

REFERENCES [1] Christina M. Rost, Edward Sachet, Trent Borman, Ali Moballegh, Elizabeth C. Dickey, Dong Hou, Jacob L. Jones, Stefano Curtarolo & Jon-Paul Maria – Nature Communications – Volume 6 – 2015 – Article number: 8485 [2] Joshua Gild, Yuanyao Zhang, Tyler Harrington, Sicong Jiang, Tao Hu, Matthew C. Quinn, William M. Mellor, Naixie Zhou, Kenneth Vecchio & Jian Luo – Scientific Reports – Volume 6 – 2016 – Article number: 37946 [3] William G.FahrenholtzGreg E.Hilmas – Scripta Materialia – 1 March 2017 – Volume 129 – Pages 94-99

656 ______Functional materials and coatings

IMPROVEMENT OF TRIBOLOGICAL AND BIOLOGICAL PROPERTIES OF TITANIUM ALLOY HIP REPLACEMENT IMPLANTS COVERED BY DIAMOND COATINGS R.D.KHALAFOV*, S. E. KUNASHENKO*, S.A.LINNIK* *Tomsk Polytechnic University, Lenina 30, Tomsk, 634034, Russia, [email protected], 89521765349

This research is focused on improving tribological and biological properties of hip replacement implants using CVD diamond coatings. Various types (micro-, ultrananocrystalline and multilayer) of well-adherent diamond coatings of different thicknesses were deposited on titanium alloy implants to protect them from mechanical wear and to increase their biocompatibility. Сomparative measurements of different diamond layers wear resistance were investigated using tribometer testing. The diffusion of doping elements (Al and Ni) from titanium alloy through different types of diamond coatings was studied using atomic-absorbing spectrometry. Bacterial growth on different diamond layers was investigated using incubation of bacteria stamp and confocal microscopy. Research results showed that using of diamond coatings on hip replacement implants highly increases their wear resistance, hilling ability and biocompatibility. Such research not have been carried out in Russia before. Development of diamond coatings on titanium implants allows applying such coatings everywhere in biomedicine implantation.

657 ______Functional materials and coatings

SYNTHESIS OF HAFNIUM-BASED MAX PHASES BY MAGNETRON SPUTTERING

D.ZELENTSOV, S. DEMCHENKO, S.ZENKIN Tomsk Polytechnic University, Lenina 30, Tomsk, 634034, Russia, [email protected], 89528947238

The special practical interest from the point of view of creating materials for the future application in mechanical engineering is caused by the so-called MAX materials, due to the unique properties of these materials, combining metallic (strength, high electrical and thermal conductivity, manufacturability) and ceramic (refractory, high Young's modulus, high microhardness) properties [1]. First, the applicability of these class of materials to high temperature applications is due to the combination of thermal shock and oxidation resistance, high thermal and electrical conductivity. In this case, the new hafnium based MAX phases (such as Hf2AlC, Hf3AlC2) may be good candidates to application for thermal barrier coatings (TBC). One of the common method for coating preparation is magnetron sputtering. For now, information of obtaining hafnium based MAX phases by this method in literature is very little, so aim of this study was directed to selection of optimal parameters of magnetron sputtering and research their physical (thermal and electrical conductivity, thermal expansion), mechanical (micro- nanohardness) properties, and also chemical composition of obtained coating. For experimental implementation were held several experimental stages: sputtering from two targets (Al, Hf) in Ar+CH4 atmosphere to unheated substrate and subsequent annealing of samples in inert atmosphere up to 1000oC and sputtering with heated substrate ( T = 400 - 1000oC). Aluminum concentration was controlled by Al target discharge current. In all experiments the pressure of argon +CH4 was constant with the value 10-2 Torr. After that, samples were investigated by XRD for identification of present phases, by laser flash analysis for thermal conductivity, and four point probe method resistivity measurement for electrical conductivity. To investigate phase transformations in samples while heating we use thermogravimetric analysis.

REFERENCES [1] M.W. Barsoum // Progress in Solid State Chemistry. -2000. -28. -201-281.

658 ______Functional materials and coatings

SEMICONDUCTOR QUANTUM DOTS DOWN CONVERTERS FOR SILICON SOLAR CELLS

A.Z.KAINARBAY, B.ABDRAMAN, G. BAZARBAYEVA, D.K. DAURENBEKOV, T.N.NURAKHMETOV, Z.M.SALIKHODJA, A.M.ZHUNUSBEKOV, B.N.YUSSUPBEKOVA L.N. Gumilyov Eurasian national university, 13, Kazhymukana street, Astana, 010000, Kazakhstan, [email protected] ,

The combination of solar cells (SC) with luminescent “down converters” based on colloidal quantum dots (CQD) have been suggested as a very promising method to high power conversion efficiencies. For “down-conversion”, the luminescent converter (LC) as like thin film contains CQD is located on the front surface of the SC. High-energy photons with energy more than Eg are absorbed by the converter and down-converted into lower energy photons which, in turn, can be absorbed by the solar cell. In this work, we investigate the use of CQD (PbS, PbS-CdS, CdSe-CdS-ZnS, CdTe) into photovoltaic technology to increase of efficiency of silicon SC. Conventional silicon SC only effectively converts photons of energy close to the Si band gap as a result of the mismatch between the incident solar spectrum and the spectral absorption properties of the material. This loss can be reduced by using photoluminescence, whereby photons are shifted into an energy range where the cell has a higher spectral response. CQD were proposed for use as down-shifters because the emission wavelength can be tuned by their size, as a result of quantum confinement. In order to analyze the effect of the LC we performed a series of optical and PV measurements. The LC or thin layers were characterized using PL measurements to verify the CQD formation and quantify their light emission. There is a high PL emission with a peak at 627 nm (CdSe/ZnS), 761 nm (CdTe), 875 nm (PbS/CdSe), respectively. Figure 1 showed spectra of diffuse reflectance of SC(1), luminescence spectrum of CdSe/ZnS(2), CdTe(3), PbS/CdS(4).

659 ______Functional materials and coatings

PHOTOLUMINESCENCE OF HAFNIUM AND ZIRCONIUM GERMANATES

V.E. PROKIP*, V.V. LOZANOV*, A.S. BEREZIN**, N.I. BAKLANOVA* * Institute of Solid State Chemistry and Mechanochemistry SB RAS, Kutateladze st.18, Novosibirsk 630128 Russia, [email protected], (383) 233-24-10 **Nicolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Ave. 3, Novosibirsk, 630090, Russia

Nowadays, oxide-based ceramics and glasses are widely used as scintillators, illuminators, lenses and laser media. Among oxide-based materials, zirconium and hafnium dioxides are of special interest because of their high hardness, transparency, chemical and high thermal stability. These properties make ZrO2 and HfO2 the excellent optical materials, for example, as scintillators with high stopping power for gammas and X-rays, waveguides, thermal luminescence emitters, and solar absorbers. Scheelite-like germanates HfGeO4 and ZrGeO4 were practically not considered in terms of their optical properties. Nevertheless, there is a rationale for consideration these compounds as the promising high-temperature phosphors. Furthermore, these compounds can be obtained in a thin-film state, which can expand the field of their application. It is widely known that the many functional properties of oxide-based materials including luminescence properties are directly connected with morphology, texture, and phase composition that, in its turn, depend on the method and parameters of preparation. This work was focused on the comparative study of the ultraviolet/photoluminescence (UV/PL) conversion properties of hafnium and zirconium germanates derived by different chemical routes. Hafnium and zirconium germanates (HfGeO4 and ZrGeO4) were synthesized by two different techniques, namely, so-called ceramic route and co-precipitation ones. Ceramic route involved thorough mixing of the corresponding quantities of ZrO2 (or HfO2) and germanium oxides with the agate mortar following by the heat-treatment of mixture at 1200C (1300C) in air. Additionally, preliminary mechanical treatment of ZrO2 (or HfO2) and GeO2 powders was applied (planetary ball mill) at a constant speed with time ranging between 5 and 60 min following by the heating to 1200C or 1300C in air. The second approach involved dissolution of the appropriate amounts of ZrOCl2 or HfOCl2 in deionized water to form 0.1 M solutions. GeO2 was mixed with de-ionized water with following drop-by-drop addition of concentrated ammonia under stirring to obtain 0,1 M solution. The appropriate volumes of as- prepared solutions were mixed under continuous stirring to obtain MGeO4 precursors. The obtained precipitates were dried in air and was heated on air/in vacuum at 1000C for 2 h. The corrected photoluminescence spectra (PL) of the initial oxides and products were recorded on Fluorog 3 (Horiba Jobin Yvon) spectrometer equipped with a cooled PC177CE-010 photon registration module with photomultiplier P2658. Samples were irradiated with monochrome ultraviolet source with a wavelength of 250 nm. The analysis of spectra was performed with Fityk 0.9.08 software. Voigt profiles were applied to the peak-fitted determination. For the first time the photoluminescence spectra of hafnium and zirconium germanates optical spectra were obtained (Fig. 1). The alleged defects are revealed, the main differences in the nature of the sample irradiation depending on the conditions for their production are shown.

Fig. 1. The photoluminescence spectra of ZrGeO4 obtained by ceramic route at 1300°C (left) and it’s optical image upon excitation with 5,17 eV illumination (right)

660 ______Functional materials and coatings

INFLUENCE OF PARAMETERS IN THE PLASMA DYNAMIC SYNTHESIS PROCESS ON ULTRADISPERSED ZINC OXIDE 1

A.I. TSIMMERMAN*, YU.L. SHANENKOVA**, M.I. GUKOV* *Student of National research Tomsk Polytechnic University Lenin Avenue 30, Tomsk, 634050, Russia, [email protected], +7(952) 893-87-32 **Ph.D student of National research Tomsk Polytechnic University Lenin Avenue 30, Tomsk, 634050, Russia

Zinc oxide is one of the promising n-type semiconductors due to its low cost, environmentally friendly and good electronic properties. ZnO has a wide range of applications: electric power industry, oil refining industry, pharmaceuticals and medicine [2]. There are many ways to produce zinc oxide: sol-gel method, chemical, thermal and hydrothermal methods [1, 3, 4]. These methods have some disadvantages: high cost, time consumption and production process complexity. Also all methods do not allow to obtain a sufficiently high-quality product. A highly dispersed single crystal structure of particles can be obtained by crystallization from the liquid phase with a high quenching rate of the material under supersonic sputtering conditions in a gaseous atmosphere. Such conditions can be obtained by implementing a plasma dynamic method based on a pulsed coaxial magnetoplasma accelerator of erosion type [5]. The plasma dynamic method provides for the synthesis of zinc oxide up to 10 g during one short-term cycle of the accelerator operation (up to 1 ms). The basic precursor is produced by erosion of the zinc barrel. The zinc plasma structure interacts with ionized oxygen, supersonic spraying of product liquid phase and its crystallization in gaseous oxygen medium occurs. As a result of the plasma chemical reaction, a nanodispersed powder is synthesized. The collection of material is carried out some time after the end of the working cycle. The work presents the results of the conducted experiments on the effect of energy (charge voltage U = 2.7 ÷ 3.8 kV, charge capacity C = 3.6 ÷ 7.2 mF) and structural (barrel material) parameters of the plasma dynamic synthesis process for the final yield of the product. It is proved that, the accelerator system parameters do not affect the entire synthesized product. The obtained material consists of a phase of hexagonal zinc oxide (100%), without any additives. In general, the particles are presented in the form of a single-crystal hexagonal structure and on average their size varies from several nanometers to 350 nm. A wide distribution of particle sizes can positively affect the creation of ceramic samples by the method of spark plasma sintering. REFERENCES [1] Gu H., Yu L., Wang J., Yao J., & Chen F. // Materials Letters. – 2017. – 196. P. 168-171. [2] Raula M., Rashid M. H., Paira T. K., Dinda E., & Mandal T. K. // Langmuir. – 2010. – 26. – №. 11. P. 8769-8782. [3] Sazonov R., Kholodnaya G., Ponomarev D. V., Remnev G. // Journal of the Korean Physical Society. – 2011. – 59. – №. 6. – P. 3508-3512. [4] Djurisic A. B., Chen X., Leung Y. H., & Ng A. M. C. // Journal of Materials Chemistry. – 2012. – 22. – №. 14. – P. 6526-6535. [5] Shanenkova Y., Sivkov A., Ivashutenko A., Tsimmerman A. // Journal of Physics: Conference Series. – 2017. – 830. – № 1. P. 012087.

1 This work was supported by the project RFBR No. 18-32-00115

661 ______Functional materials and coatings

MODELING OF THE PROCESSES OF IONIC CONDUCTIVITY IN A SOLID OXIDE ELECTROLYTE BASED ON ZrO2

SALIKHODZHA ZH.M., NURAKHMETOV T.N., KUTERBEKOV K.A., SADYKOVA B.M., ZHUNUSBEKOV A.M., KAINARBAY A.ZH., DAURENBEKOV D.KH., ZHANGYLYSOV K.B. L.N. Gumilyov Eurasian National University, 13, K. Munaytpassov Str., Astana, Kazakhstan

Currently, in connection with scientific and applied research in the search for alternative energy sources and increasing the efficiency of known sources, the study of solid oxide fuel cells (SOFC) is an urgent task of modern physics and chemistry. The main components of the SOFC are anode, cathode and electrolyte. As the anode material, cermet is often used from nickel and solid oxide electrolyte, and lanthanum-strontium manganite compounds are used as the cathode. It is known, that solid oxide fuel cells (SOFCs) are more effective among alternative energy sources. For such qualities as efficiency, environmental friendliness, fuel quality and noise level in the production of electricity, SOFCs are more efficient than other sources of electricity. In SOFC, natural gas, methane, butane, propane, etc. can be used as fuel. The use of hydrogen as a fuel makes SOFC more environmentally attractive. In this case, emitted into the atmosphere water vapor, which is formed during the electrooxidation of hydrogen. Pure oxygen or air is an oxidizer in SOFC. Oxygen is reduced to ions, which are transported through the oxygen vacancies of the crystal lattice of the solid electrolyte and react at the anode with hydrogen to form water. In order for these reactions to occur, the anode and cathode must be connected to the load. Then an electric current flows through the external circuit. At present, the search continues for mechanically strong new oxide materials with anionic conductivity. It is known that a nanostructured oxide ceramics based on ZrO2 possesses increased physical and chemical properties compared to ceramics obtained by commonly used industrial methods or by solid-phase synthesis. If metal impurities with a lower valence are introduced into zirconia, they will usually occupy cationic sites. In this case, oxygen ions leave the lattice in such a quantity that the electroneutrality condition is fulfilled. For example, if atoms of bivalent calcium are introduced, then for each introduced atom there will be one remote oxygen ion. Modeling of the ionic conductivity processes in a solid electrolyte based on zirconia will use a package of semi-empirical quantum chemical programs MOPAC-2016 in the PM7 approximation. We constructed a model of zirconium dioxide, consisting of 96 atoms, i.e. 32 atoms of Zr, 64 oxygen atoms corresponding to the cubic structure. The dimensions of the nanostructure under consideration were about 14, 13 and 12 angstroms, respectively, in three directions. The ionization potential is 3.553 eV. The width of the band gap, defined as the energy difference of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), was 3.2 eV. This value of the width of the forbidden band is much smaller than the experimental value, which is 6 eV. The paper will discuss the results of quantum-chemical modeling of the migration of oxygen ions in the cubic structure of a pure crystal ZrO2 and stabilized zirconia with CaO, MgO impurities.

662 ______Functional materials and coatings

IR SPECTRA INVERSTIAGATION OF H2 IN SILICA AEROGEL

Lazebnykh V.Yu.*, Mysovsky A.S.*', Sinitsa L.N.**, Lugovsky A.A.** *Irkutsk National Research Technical University, 83, Lermontov street, 664074 Irkutsk, Russia, [email protected], +79500996560 ' Vinogradov Institute of Geochemistry SB RAS, 1А Favorsky str., Irkutsk, 664033, Russia **V.E. Zuev Institute of Atmospheric Optics SB RAS, 1, Academician Zuev square, Tomsk 634055 Russia

The observation of an impact of gas pressure on an H2 IR spectra in silica aerogel is presented in this paper. A silica aerogel sample had a cutted cone form with 15x15x60 mm sizes and 0.035 g/cm 3 of volume density. We measured the spectra by spectrometer with 8 cm-1 resulution (see fig.1). We fitted this lines by a surface using the formula: ω−Ω 2 ω−Ω 2 1 2 − − 2 2σ 2 2 σ a ⋅p+b ⋅p ( 1 ) a ⋅p+b ⋅p ( 2 ) f ( ω,p )= 1 1 e + 2 2 e √2π σ1 √2π σ 2

A fit estimation error was less than the oscillation which is in 4040-4080 cm-1 frequency range. See fitting parameters in table 1. So we got two peaks. The first peak has linear dependence on Fig.1 pressure. We associated it with the porous wall. There is a Fitted IR H2 spectra. strong electrostatic field in a space near a porous surface. Table 1.The space has 15 angstrom width according our ab initio Parameter The first peak The second peak modeling. A magnitude of electric field we estimate using an experimental peak displacement and we got 0.008 a.u. or a, cm-2·atm-1 0.02 0 4.1·10 7 V/cm. It corresponds to [1]. The linear coefficient ‘a’ is proportional to a fraction of the space width and a b, cm-2·atm-2 0 0.0067 porous radius. So value of the ‘a’ can be used to estimate porous radius. σ, cm-1 8.49 28.02 The second peak has a quadratic dependence on pressure. We supposed that this peak corresponds intermolecular interaction. Ω, cm-1 4141.05 4134.40 References [1] Ken-Ichi Honma, et al. Adsorption 4, 233–237 (1998)

663 ______Functional materials and coatings

DIELECTRIC PROPERTIES OF THE PEROVSKITE-LIKE OXIDES СaСu3Тi4-XMXО12 (M = Zr, V, NB) PREPARED BY HIGH TEMPERATURE – HIGH PRESSURE SYNTHESIS 1

N.V. MELNIKOVA*, N.I. KADYROVA**, A. MIRZORAKHIMOV*, T.I. CHUPAKHINA**, YU.G. ZAYNULIN**, D.O. ALIKIN* *Ural Federal University, Institute of Natural Sciences and Mathematics, 51, Lenin ave., Ekaterinburg, 620000, Russia, [email protected], +79221105853 **Institute of Solid State Chemistry, UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russia

The perovskite-like СaСu3Тi4О12 (CCTO) is attracting considerable attention due to the unique physical properties including the most known such as giant permittivity effect the origin of that is still being discussed. In earlier papers we showed that high temperature – high pressure synthesis leads to an increase in the permittivity (as compared with the permittivity of materials synthesized by solid-state reaction) for CCTO and for a number of perovskite-like phases with the structure K2NiF4 [1-3]. As a result of the high temperature – high pressure effects, the grain size in CCTO significantly increases too [1, 2]. The ame of this work is to reveal the effect of the composition, morphology, microstructure and external influences on the dielectric constant of the synthesized materials based on CCTO. For this purpose the dielectric properties of materials synthesized by various methods, including high temperature – high pressure method, and materials obtained as a result of partial substitution of titanium atoms in the CCTO for atoms of zirconium, vanadium and niobium, have been studied. The samples СaСu3Тi4-xMxО12 (M = Zr, x = 0.3; M = V, x = 0‒0.5; M = Nb, x = 0.5) have been synthesized at high pressures (2.5 GPa – 10 GPa) and temperatures (900º C -1100º С) in a toroid-type high- pressure chamber. For comparative studies, the samples CCTO and СaСu3Тi4-xNbxО12 were also synthesized by solid-state reaction [2]. Series of samples ССТО were preparated using solution combustion method for the synthesis of powders using the different fuels (citric acid and diammonium citrate) and their subsequent sintering. All synthesized phases crystallize in a cubic symmetry (space group Im-3, Z = 2) and have a perovskite-like structure. The electrical properties were studied in a wide range of temperatures (10‒600 K) at atmospheric pressure and pressures (10 GPa to 50 GPa) at room temperature, on DC and AC (1 Hz-32 MHz) (Solartron 1260A and the ModuLab Materials Test System). For the topography and the electrical current profile studies in some samples the scanning probe microscopy (SPM) technique was implemented in the contact spreading resistance mode (SPM Asylum MFP3D). The studied compounds are characterized by a high dielectric constant (~ 103-105). The high temperature – high pressure processing increases the dielectric permittivity of the materials. By analyzing the influence of the morphology features, the grain characteristics, of temperature and pressure effects on the dielectric properties of materials, it was concluded that not only the Maxwell-Wagner polarization processes (or internal barrier layer capacitors (IBLC) model [4]) is responsible for the high values of the dielectric constant. But, in the main, the Nano Barrier Layer Capacitance (NBLC) model [5] and the small polaron hopping conduction mechanism, which take into account the intragranular effects, can explain the high dielectric properties of studied materials. REFERENCES

[1] N.I. Kadyrova, Y.G. Zainulin, N.V. Mel’nikova, I.S. Ustinova, I.G. Grigorov // Bulletin of the Russian Academy of Sciences. Physics.  2014.  V. 78.  № 8. P. 719-722. [2] N.I. Kadyrova, N.V. Mel’nikova, I.S. Ustinova, Yu.G. Zainulin // Inorganic Materials.  2016.  V. 52.  № 10. P. 1051-1054. [3] Т.I. Chupakhina, N.V. Melnikova, N.I. Kadyrova, А. Mirzorakhimov, А.V. Tebenkov, Yu.А. Deyeva, O.I. Gyrdasova, Yu.G. Zainulin // Materials Research Bulletin.  2016.  V. 77.  P. 190-198. [4] D.C.Sinclair, T.B. Adams,F.D. Morrison,A.R. West // Applied Physics Letters.  2002.  V. 80.  № 12. P. 2153-2155. [5] W.C. Ribeiro, E. Joanni, R. Savu, P.R. Bueno // Solid State Communications.  2011.  V. 151.  № 2. P. 173-176.

1 This work was supported by the Russian Foundation for Basic Research, projects No. 16-02-00857-a.

664 ______Functional materials and coatings APPLICATION OF THE INTERNAL PROTECTIVE LAYER FROM CORROSION-RESISTANCE STEEL TO THE SURFACE OF A LONG-LENGHT PIPES WITH AN EXPLOSIVE WELDING1

A.Yu.MALAKHOV, I.V.SAIKOV

Merzhanov Institute of Structural Macrokinetics and Materials Science Russian Academy of Sciences, Academician Osipyan str., 8 Chernogolovka Moscow Region, 142432, Russia, [email protected], +79854579221

The using special types of metal coating leads to an increase in the service life of the equipment. There is a wide range of protective materials depending on operating conditions. There is a serious problem in the petroleum industries now. It consists in excessive wear of the inner surface of pump-compressor pipes. Consequently, at the report it is suggested that an explosive welding for the cladding inner side of a steel tube by corrosion-resistance steel. However, it should be noted that, in the practice of using explosive welding for the production of bimetallic pipes, there is such a problem as a significant reduction in the quality of the joint as the point of contact is far removed from the site of initiation [1]. At a distance of about 8-10 or more diameters from the point of initiation, the mechanical properties of the welded joint decreases and even leads to the destruction of the cladding layer. It should be noted that the quality of the connection is undoubtedly influenced by the gas in the gap between the welded pipes that is compressed and moves ahead of the contact point with hypersonic speed. Since in this case there is no lateral outflow of gas, there is an increase in its temperature and, accordingly, the temperature of the surfaces of the pipes in contact with the heated gas. As the distance from the initiation point increases, the gas warms up more and thus affects the stability of the process and the quality of the connection of the initial elements [2]. In the work were carried out experiments to evaluate of influence parameters of explosive welding and experimental scheme on the quality welding joint and the degree of deformation of the two layer tube blanks 2,5 meter length. The raw materials used were pipes made of steel 37Mn2V (base layer 12 mm thick) and 08Cr18Ni10T steel (cladding layer 2,5 mm thick). The outer diameter of the pipe for the main layer was 108 mm and that of the stainless pipe was 80 mm. The pipes were 2,5 meter long. The welding gap was filled with an inert gas – helium. According to the scheme, the internal cavity of the collected pipes was filled with a solid-liquid medium as a mixture of a steel shot and water was used as the supporting element. The speed of the contact point was 2800–2900 m/s. Sandblasting was used to stabilize the detonation and prevent excessive expansion of explosives. As a result of experiments 2,5 meter samples of bimetallic tube billets were produced (Figure 1).

a b c Figure 1 – Production of bimetallic tube: a – assemble before explosive welding; b – produced according bimetallic tube said method; c – bimetallic annular sample

REFERENCES

[1] Dobrushin, L.D., Fadeenko, Yu.I., Illarionov, S.Yu.,and Shlenskii, P.S. // Channel effect in explosion welding,Avtom. Svarka, 2009, no. 11, pp. 19–21. [2] Pervukhin, L.B., Pervukhina, O.L., and Bondarenko, S.Yu. // Theoretical and technological basis for industrial production of bimetals, Izv. Volgograd. Gos. Tekh. Univ., 2010, no. 4, pp.75–82.

1 This work was supported by the Russian Foundation for Basic Research, project no. 17-08-01248А.

665 ______Functional materials and coatings EFFICIENCY OF CYLINDRICAL POROUS BURNERS1

E.P.DATS*,**, T.P. MIROSHNICHENKO*, A.I. KIRDYASHKIN*,***, A.S. MAZNOY*,*** *Far Eastern Federal University, 8 Sukhanova str., Vladivostok, 690090, Russia, [email protected], 007(423)265-22-32 **Vladivostok State University of Economics and Service,41 Gogolya str.,Vladivostok,690014,Russia ***Tomsk Scientific Center Siberian Branch of the Russian Academy of Sciences,10/4 Akademicheskiy ave.,Tomsk,634055, Russia

Development of thermal energy sources based on the gas combustion with controlled temperature and capacity characteristics is an actual problem in modern science and industry. Combustion in porous media is one of the effective methods for burning gaseous fuels. Combustion here occurs with heat exchange between the flame zone with a porous body. Heat from the combustion zone is transferred along the porous frame towards the gas flow and heats the mixture of initial reactants. In contrast to the open (unrestricted) flames, porous burners are characterized by the possibility of combustion of the lean mixtures, a broad range of power adjusting, the higher firing rates and better environmental category. The porous body is heated and emits the energy from the outer surface in IR range. Due to this effect, porous burners are successfully used for heating industrial zones and creating electricity generators based on TPV modules, as well as for drying and thermal processing of materials [1-3]. The main characteristic of the radiant porous burner is the radiation efficiency, η, which is defined as the ratio of the amount of radiated energy value to the total capacity of the burner. The radiative characteristics of porous burners are largely determined by the temperature of the outer surface of porous body which, in turn depends on the rate and kinetics of burning reaction, flame localization and the characteristics of the material. The cylindrical form of the burner contributes to a uniform gas supply and uniform stabilization of the flame front inside the porous body. It allows to translate the energy of the fuel to the radiation most effective [4]. The aim of this study is to determine the porous body parameters which influence on the radiation efficiency of the cylindrical burner. Simulation is carried out within the frame of a two-temperature diffusive-thermal model [5], consisting of the thermal conductivity equations for a solid porous frame and gaseous fuel, and diffusion equation for the lacking component of the gas mixture. Quartz has been chosen as material of the porous body. Numerical solutions have been obtained for the different porosity values, m, and average pore diameter, dp. It has been found that porosity has significant effect on the radiative efficiency of the burner. In instance, for m = 0.5 the maximal value of η is 25% and for m = 0.7 the maximal value of η is 43%. Calculations for m = 0.7 are consistent with the experimental data obtained in [5]. It should be noted that efficiency of the porous burner increases with further increase in porosity. However, the maximum of porosity is limited by the strength characteristics of porous material. If the porous body is heated unevenly then the thermal stresses occur, which are able to destroy the porous body. The estimate of influence of the average pores diameters on the maximal radiation efficiency value has been also made. Calculation results have revealed that there is an optimal value of dp = 4 mm, at which the maximum efficiency is achieved for the given porosity value. The efficiency is less by 5-10% for the range of values dp1;4  4;6 (mm). It has been established that the optimal pore diameter for the considered porous material, is the same for different porosity values in the investigated range of 0.5 < m < 0.8. Proceeding from the obtained results, it can be concluded that for a particular porous burner the maximal radiation efficiency is achieved at a certain average pore diameter and maximal possible porosity (if only remains the structural strength of the material). REFERENCES [1] Howell J., Hall M., Ellzey J. // Progress in Energy and Combustion Science.  1996.  Vol. 22. Pp. 121-145. [2] Kennedy L., Fridman A., Saveliev A. // International Journal of Fluid Mechanics Research.  1996.  Vol. 22. Pp. 1-26. [3] Takeno T., Sato K. // Combustion Science and Technology.  1979.  Vol. 20. Pp. 73-84. [4] Fursenko R., Maznoy A., Odintsov E., Kirdyashkin A., Minaev S., Sudarshan K. // International Journal of Heat and Mass Transfer.  2016.  Vol. 98. Pp. 277-284. [5] Palesskii F.S , Fursenko R.V., Minaev S.S. // Combustion, Explosion, and Shock Waves. – 2014. – Vol. 50. – № 6. Pp. 625- 635.

1 This work was supported by RFBR according to the research project №18-38-00523.

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