Publications on the project |
015 Формування лінійних вуглецевих ланцюжків та атомних кластерів полями високої напруги |
Authors: | Mazilova T.I., Kotrechko S., Sadanov E.V., Ksenofontov V.A., Mikhailovskij I.M. | |
Summary: | Linear forms of carbon are important in a wide variety of applications, ranging from highly conducting interconnects to field emission materials. By methods of field ion microscopy (FIM) and mass-spectrometry, it was revealed that linear carbon chains were present at the surface of carbon fibers after high-voltage treatment. The carbon chains attached to the specimen tips were produced in situ in a field ion microscope by unraveling of nanofibers using low-temperature evaporation in electric fields of the order of 1011 Vm−1. The unraveling of graphite is possible due to the ultimate strength of the monoatomic carbon chain. The maximum force before failure of carbon chains at 0 K is 7.916 nN at a strain of 0.19 and the ideal tensile strength is equal to 252.1 GPa. Molecular dynamics simulations and high resolution FIM experiments are performed to assess the evaporation of atomic chains under high-field conditions. One can conclude that ions are field evaporated from a graphite surface initially in linear cluster forms, which decompose mostly into smaller atomic clusters and individual ions because of the ultrahigh-temperature excitation during unraveling. | |
Keywords: | atomic chain; electric field; field ion microscopy; carbon | |
Edition: | International Journal of Nanoscience 2010, Vol. 9, No. pp. 151–157 | | | 2010,
151–157,English |
015 Experimental determination of the mechanical strength of monatomic carbon chains |
Authors: | S. A. Kotrechko, A. A. Mazilov, T. I. Mazilova, E. V. Sadanov, I. M. Mikhailovskij | |
Summary: | The ultimate tensile strength of monatomic carbon chains has been determined using the method of high-field mechanical loading in a field-ion microscope. The maximum stress tearing of monatomic carbon chains (181 GPa) experimentally observed at 77 K amounts to about 70% of the value calculated for an ideal chain and significantly exceeds the tensile strength of well-known carbon materials, including carbon nanotubes and graphene. | |
Keywords: | carbon atomic chains; graphene; carbyne; upper strength limit, high-field method | |
Edition: | Technical Physics Letters. February 2012, Volume 38, Issue 2, pp. 132-134 | | | 2012,
132-134,English |
015 High-Field Formation of Multi-point Field Electron Emitters |
Authors: | A. A. Mazilov, S. A. Kotrechko, T. I. Mazilova, E. V. Sadanov, I. M. Mikhailovskij | |
Summary: | Using the field-ion and field-electron microscopy techniques, it is demonstrated that the efficiency of formation of field induced emission sources with developed (multipoint) surfaces can be increased due to the phenomenon of evaporation in a strong electric field in the presence of an active gas. The proposed emitter formation process is selfconsistent and terminates upon attaining equality of local field factors over the vertices of point emitters irrespective of their initial distribution with respect to the radius of curvature and the local factor of mutual screening. | |
Keywords: | atomic chain; electric field; field ion microscopy; carbon. | |
Edition: | Technical Physics Letters, 2012, Vol. 38, No. 4, pp. 340–343 | | | 2012,
340–343,English |
015 Measurement of the inherent strength of carbon atomic chains |
Authors: | S. A. Kotrechko, Mikhailovskij I.M., Sadanov E.V., Ksenofontov V.A., Mazilova T.I. | |
Summary: | The intrinsic strength of freestanding carbon atomic chains was measured by in situ high-field mechanical testing of carbon atomic chains carried out inside a field-ion microscope. The determined breaking field strength corresponds to a tensile strength of carbon atomic chains at 5 K equal to 245 GPa. Carbon atomic chains also show exceptionally high-evaporation stability in electric fields up to 259 V/nm. The tensile strength of linear carbon chains significantly exceeds the tensile strength of known two-dimensional and three-dimensional carbon materials, including carbon nanotubes and graphene. Our results can be considered as direct experimental evidence for Pauling’s prediction of bond stiffening with reduced atomic bond order. | |
Keywords: | carbon atomic chains; graphene; carbyne; upper strength limit, high-field method. | |
Edition: | Physical review. 2013, B 87, 045410 | | | 2013,
045410-1 - 045410-7 ,English |
015 Features size effect during the deformation of bcc-metal nanocrystals in the direction of <110> |
Authors: | S. Kotrechko, V.V. Lidych, O. Ovsjannikov | |
Summary: | Influence of the size of bcc-nanocrystals on the strength level regularity for a wide range of samples diameter values from 1.2 to 25.1 nm as a result of computer simulation using molecular dynamics (MD) method has been established. The fact that as opposite to nanocrystals with fcc lattice, with the decreasing of bcc nanocrystals size the strength in the direction <110> is not only increasing but, vice versa, decreasing has been found for the first time. Within the authors' developed concept of local lattice instability as a mechanism which controls the nanocrystal strength level it has been shown that the cause of this effect is the shear stress values increasing in the local area, where the crystal loses stability, as a result of surface tension. An analytic dependence for the predicting of nanocrystal size and magnitude of surface tension forces effect on the level of its strength has been proposed. | |
Keywords: | Nanosized crystal, strength, size effect, local instability, surface tension. | |
Edition: | | | | 2012,
1517-1527,Ukrainian |
015 Strength hierarchy for nano-sized crystals |
Authors: | S. Kotrechko, I. Mikhailovskij, T.Mazilova, O. Ovsjannikov | |
Summary: | A concept of atomic mechanisms governing strength of nano-sized defect-free crystals is presented. It is exhibited that these mechanisms consist in local instability of the lattice. Two main reasons for localization of instability in three-dimension (3D) crystals are analyzed, namely, (i) fluctuation of local stresses induced by thermal vibrations of atoms, and (ii) non-uniform distribution of local stresses caused by a surface tension. Based on this conception, explanations of both the temperature dependence of strength of 3D nanocrystals and scale effect are given. Ideas on the reasons for and regularities of change in strength at transition from 3D to 2D (graphene) and 1D (monatomic chain) crystals are represented. It is shown that dimensionality of crystal is one of the main factors governing strength of defect-free crystals. Experimental values of the strength of carbon monatomic chains are given, which ≈ 2 times exceeds the strength of graphene and is the highest attainable level of strength in the world. | |
Keywords: | Nanoneedles, nanopillars, graphene, nanotubes, carbon atomic chains, strength
| |
Edition: | Key Engineering Materials. Vols. 2014, 592-593, pp. 301-306. | | | 2014,
301-306,English |
015 Абсолютна верхня межа міцності матеріалу та способи її досягнення |
Authors: | S. Kotrechko, A. Timoshevskij, S. Yablonovskii, I. Mikhailovskij, T. Mazilova, V. Lidych | |
Summary: | Ideas on the nature of strength of defect-free nano-sized crystals are presented. Findings on experimental determination of uniaxial tensile strength of carbyne (linear allotrope of carbon) are given. It is found that carbynes’ strength exceeds 270GPа. This is significantly greater than the maximum strength level 130GPа ascertained in 2008 for graphene. It may be expected that this is not the next “all-time high” for strength but it upper limit. Based on the results of ab-initio calculations and molecular-dynamics simulation, it is exhibited that dependence of strength on dimensionality is key specific feature of nano-scale crystals. Increase in strength at transition from 3D-crystal (diamond) to 2D-crystal (graphene) and 1D-crystal (carbyne) is demonstrated for carbon. It is shown how carbynes can be used for creation of ultra-high-strength bulk materials. Requirements to structural parameters of such materials are formulated and assessment of their strength is given. | |
Keywords: | nanocrystals; carbon atomic chains; graphene; carbyne; upper strength limit, nano-pillars, nano-needles. | |
Edition: | Procedia Materials Science. 2014, 3, pp. 391-396 | | | 2014,
391-396,English |
015 Ferromagnetic Nanoparticles in Cu-Mn-Al Melt Spun Ribbons |
Authors: | S.M.Konoplyuk, V.V.Kokorin, V.M. Nadutov, A.E. Perekos, L.E.Kozlova | |
Summary: | This work focuses on study of magnetic and magnetotransport properties of Cu-Mn-Al melt-spun ribbons. As shown, the system of nanoparticles is formed after annealing of the ribbons. Calculations of their average size and interparticle spacing are done using XRD patterns. The influence of ageing on field and temperature dependences of magnetoresistance is also demonstrated. | |
Keywords: | Cu-Mn-Al ribbons, magnetoresistance, ageing, nanoparticles | |
Edition: | Metallofizika i Noveishie Technologii, 2010, т. 32, № 5: cc. 571-580 | | | 2010,
571-580, |
015 Magnetoresistance of Cu-Mn-Al Melt-Spun Ribbons containing the system of interacting ferromagnetic inclusions |
Authors: | S.M.Konoplyuk, V.V.Kokorin, V.M. Nadutov, A.E. Perekos, O.V.Kolomiets | |
Summary: | The Cu-Mn-Al melt-spun ribbons of two compositions were studied to find out the influence of the collective behaviour of diluted ferromagnetic nanoparticles on magnetotransport properties. Superparamegnetic state and ferromagnetic-like ordering were revealed. It was shown that the collective behaviour of the system in both ribbons correlates with the temperature dependence of magnetoresistance. | |
Keywords: | Cu-Mn-Al melt -spun ribbons, interparticle interaction | |
Edition: | Journal of Magnetism and Magnetic Mater, 2011, 323, №6, pp. 763-768 | | | 2011,
763-768,English |
015 Influence of electrospark dispergation on magnetic and electrotransport properties of Cu-Mn-Al Heusler alloys |
Authors: | V.M.Nadutov, A.O.Perekos, V.V.Kokorin, S.M.Konoplyuk, V.Z.Voynash, T.V.Efimova, V.P.Zalutskiy | |
Summary: | The ultrafine powders of the Cu-13,1Mn-12,6Al (wt. %) alloy after electro-spark dispersion in various liquids (distilled water, kerosene and ethanol) and compacted samples were studied. The finer structure and the change of phase composition of powders and its effect on magnetic and transport properties were revealed. The XRD measurements show that amount of the ordered Cu2MnAl phase in the initial and compacted powders is lower than in the cast material that decreases the saturation magnetization in several times. The magnetic measurements have shown that the particles of the ordered phase are in the superparamagnetic state. The change of the mechanism of electric conductivity of the compacted powders from metallic to semiconducting one was found to be caused by the oxidation of the metallic particles during compacting and subsequent sintering. | |
Keywords: | Electroresistance, magnetization, ultrafine powders, Heusler alloys , electrospark dispersion | |
Edition: | Metallofizika i Noveishie Technologii, 2014, 36, № 12, сс. 1679-1694 | | | 2014,
1679-1694,Russian |
015 Effect of cyclic strain on the electrical array of carbon nanotubes |
Authors: | M. M. Nishchenko, G. Yu. Mykhailova, D.E. Aznakaeva, Yu.A. Lisynova | |
Summary: | Behavior of conductivity σ(ρ) in the array of non-oriented carbon nanotubes on their density σ(ρ) placed in the reserved volume (cylinder under a piston) are studied, in process of cyclic deformation: loading - unloading. At the first cycle of compression conductivity increases by 6 times of magnitude in the range of density ρ=0,05-0,11 g/cm3 and reaches the value σ=0,71 (Ohm•cm)-1, and then gradually increases at 48% (ρ=0,86 g/cm3) was found. During unloading the volume is increases and the curve of electrical conductivity σ(ρ) for the first cycle of measurements observed two jumps in the times of 4 and 3, respectively, which are separated by a step with a value of σ=(2,4±0,3)•10-5 (Ohm•cm)-1. Such features of σ(ρ) are observed in the processes of compression and unloading for the second and subsequent cycles of measurements. Electrical conductivity is decreases in 4-5 times at a maximal density during cyclic compression and unloading. The ordering of nanotubes and the appearance of preferred orientation of the axis perpendicular to the current lines. After a 4-second cycle impacts on the curve σ (ρ) oscillations appear in the range of ρ from 0,4 to 0,8 g/cm3, whose number for the 4th cycle is equal to 2 and a 12th increase to 4th. | |
Keywords: | Carbon nanotubes, cyclic deformation, electrical conductivity, mechanical compression | |
Edition: | Metallofizika i Noveishie Tekhnologii, 2011, V. 33, №10, pp. 1153-1160 | | | 2011,
1153-1160,Russian |
015 Electrical and thermoelectric properties of composite LaNi5 with carbon nanotubes |
Authors: | G. Yu. Mykhailova, Yu. F. Suskaya, B. V. Kovalchuk, D.E. Aznakaeva, V.Yu. Moskovka, M. M. Nishchenko, M.Ya. Shevchenko, A.G. Dubovyi | |
Summary: | Electrical and thermoelectric properties of nanocomposite microparticles LaNi5 and carbon nanotubes (CNT) with an average diameter of 10±2 nm were studied in the process of establishing electrical contact between the compression deformation, which leads to a change in the orientation and geometry of CNT. Electrical conductivity (σ) of the composite with the CNT in 19,7 wt.% is an order of magnitude higher in comparison with the σ array CNT, and with concentrations CNT less than 5 wt.% the Seebeck coefficient (which has a positive sign) is decreasing by one order. Mechanism of growth σ and decline α is the transfer of conduction electrons from the metal to the CNT. | |
Keywords: | carbon nanotubes, LaNi5, electrical conductivity, thermopower | |
Edition: | Naukoemni tekhnologii, 2011, № 3/4 (11-12), pp. 86-91 | | | 2011,
86-91,Ukrainian |
015 The formation of effective electron emitters in a laser evaporation oriented carbon nanotubes |
Authors: | Sidorchenko I.M, Schur D.V., Nyschenko M.M., Shevchenko M.Ya., Bogolepov V.A., Dubovyi A.G. | |
Summary: | The processes of electron emission from the surface of oriented carbon nanotubes on the Ni substrate under the influence of pulsed laser energy are investigated. In the case of the laser pulse energy E ≥ 0.3 J, the carbon nanotubes evaporation from the surface of Ni substrate and further carbon deposition on the molybdenum anode in the form of film, which consists of spherical carbon nanoparticles with the sizes from 50 to 500 nm, take place. This leads to a change in the sign of the emission current (emission flows from the anode to the cathode). Structure formed on the Mo anode is more efficient emitter as compared with the emitter of close-packed oriented multilayer nanotubes on the Ni substrate. | |
Keywords: | Carbon nanotube electron emission, the laser light, the inversion of the current | |
Edition: | Nanosystems, nanomaterials, nanotechnology, 2012, v.10, №1 pp. 169-177 | | | 2012,
169-177,Russian |
015 Electrical and elastic properties of carbon nanotubes block after irradiation by high-energy electrons |
Authors: | V. V. Anikeyev, B. V. Kovalchuk, V. M. Lazorenko, G. Yu. Mikhailova, M. M. Nishchenko, V. N. Pimenov, I. M. Sidorchenko, Yu. F. Suskaya, V. I. Tovtin | |
Summary: | The effect of electron irradiation with the 21 MeV and a dose of up to 2,2 1017 el/sm2 of array of multi-layer carbon nanotubes (CNT) on the electrical conductivity, thermal electromotive force and the coefficient of elasticity. The results of these changes in the characteristics of the irradiated array of two types of CNTs - annealed and unannealed ones - are presented. The irradiation annealed nanotubes significantly reduces (by about two times) the conductivity and the coefficient of elasticity of the material in the pressing direction and about half increases thermoelectromotive power. The impact of the electrons on the unannealed CNT array with the same dose of irradiation also leads to a marked reduction of its coefficient of elasticity, but contributes to a significant increase in the electrical conductivity and thermoelectromotive power of the material. The observed effects are discussed in terms of the specifics of the formation of radiation defects in the nanotubes and their interaction with primary defects in unannealed samples. | |
Keywords: | Carbon nanotubes, high-energy electrons, electrical conductivity, Seebeck coefficient, annealing, deformation | |
Edition: | Perspektivnye materialy, 2013, №11, pp. 22-28 | | | 2013,
22-28,Russian |
015 Effect of high-energy electrons on electrical conductivity and defect structure of multi-layer carbon nanotubes |
Authors: | L. I. Ivanov , V. M. Lazorenko, G. Yu. Mikhailova, M. M. Nishchenko, Yu. M. Platov, S. I. Sadykhov, V. I. Tovtin | |
Summary: | The effect of high energy electrons on the electrical properties of spatially non-oriented multilayer carbon nanotubes (CNT) were studied in process of cyclic deformation: loading – unloading. CNT was placed in the reserved volume (cylinder under a piston). The conductivity of the CNT increases two to five times after irradiation by high energy electrons due to the occurrence of defects. Elasticity of carbon nanotubes in process of cyclic deformation changing due to the action of two mechanisms: the first one leading to a decrease in the contribution of inelastic processes associated with the ordering of nanotubes in the array, and the second one — with the formation of secondary defects in the processes of strain-relaxation. | |
Keywords: | Сarbon nanotubes, high energy electrons, cyclic deformation | |
Edition: | Perspektivnye materialy, 2013, №1, pp. 48-52 | | | 2013,
48-52,Russian |
015 γ-α-γ- martensitic transitions influence on the martensite decomposition of quenched steel |
Authors: | V. Danilchenko, V. Iakovlev | |
Summary: | The crystalline structure changes of the Fe – 24,5 wt.% Ni – 0,5 wt. % C alloy martensite as a result of annealing after cyclic γ-α-γ- martensitic transitions were investigated using the X-ray method in single crystal specimens. Resulting from carbon extraction from α-solid solution acceleration, the martensite lattice parameters ratio (c/a) have reduced during the heating up to 100 °C and partially tempered martensite with reduced carbon content down to 0,25wt.% was formed. The intensification of carbon martensite decomposition as a consequence of γ-α-γ transitions is associated with the influence of crystalline structure defects forming during the direct γ-α and the reverse α-γ transitions. | |
Keywords: | Martensitic transition, X-ray diffraction, dislocation | |
Edition: | Zeitschrift fur Kristallographie, 2011, 1, p. 273-277 | | | 2011,
273-277,English |
015 Effect of structure nanofragmentation on redistribution of carbon in phase hardened alloy |
Authors: | V.Yu.Danilchenko, L.G. Korshunov, V.V. Sagaradze, V.V. Tarasov, V.E. Yakovlev | |
Summary: | Cyclic γ-a-γ-martensitic transformation accelerated two-phase and single-phase carbon decomposition of the Fe-24.5 wt.% Ni-0,6 wt.% C martensite under low-temperature annealing. The intensification of carbon martensite decomposition as a consequence of γ-α-γ transitions is associated with the influence of crystal structure defects (dislocations, low-angle dislocation subboundaries of the fragments, deformation twin boundaries), formed unde ther γ--γ- transformations. | |
Keywords: | Austenite, martensite, solid solution decomposition | |
Edition: | Metallofysika i novejshie technologii, 2011, т. 33, № 3, с. 281-287 | | | 2011,
281-287,Russian |
015 Redistributin of carbon in nanofragmented iron-nickel alloy under diffusion annealing |
Authors: | V.Yo.Bondar, V.Yu.Danilchenko, V.V. Sagaradze, V.V. Tarasov, V.E. Yakovlev | |
Summary: | Diffusion characteristics of carbon atoms in metastable alloy Fe – 32 wt.%Ni with nanofragmented structure were investigated by X-ray method. Nanofragmented structure was obtained using cyclic martensitic -transitions. The significant carbon diffusion acceleration on dislocations and nanofragments subboundaries at low temperatures was revealed. Diffusion coefficients at 100˚C, that were calculated using X-ray method, are two times smaller than coefficients, calculated using radioisotope method. Such a difference can be explained by different sensitivity of the diffusion processes on volume and crystal structure defects. | |
Keywords: | Martensitic transition, X-ray method, radioisotope method, diffusion coefficient | |
Edition: | | | | 2013,
373-378,Ukrainian |
015 Determining size of nanostructured elements in multiphase quasicrystalline cotings |
Authors: | V.N.Dneprenko, V.V.Zholud, S.M.Zakharov. | |
Summary: | The films from an alloy of composition Al60,7Cu25,4Fe10Cr1,6 prepared by an ion-plasma sprayed coating were investigated. The X-ray analysis defined presence the decagonal quasicrystalline phase and orthorhombic approximant in coating. A method for fitting of the X-ray line profiles has been applied to determine the dimension of phases presented in a structure. The approximation of the profile by pseudo-Voigt functions has been explored in different cases which frequently used in the characterization of materials by X-ray diffraction. Using the Scherrer’s method it was found that the sizes of decagonal quasicrystallines and orthorhombic approximant phases considerably differ and equal to 12.7 and 42 nm respectively. | |
Keywords: | ion plasma runback, decagonal quasicrystalline phase, orthorhombic approximant, x-rayed phase analysis, profile of line of the x-rayed diffraction, crystallite size | |
Edition: | Collection of scientific works of VІ-th International scientific conference «Functional base of nanoelectronics», Kharkiv-Crimea, 2013, cc.20-23 | | | 2013,
20-23,Russian |
015 Effect of physical and chemical influences on properties carbon nanotubes |
Authors: | А.D. Shevchenko, G.D. Ilnitskaja, M.A. Marinich, I.N. Zaitseva | |
Summary: | The properties of carbon nanotubes after different chemical processing are considered in article. It was shown that after carrying out of updating of a surface of initial powder carbon nanotubes and after additional chemical processing by ferromagnetic particles of iron their magnetic characteristics amplify by order. It was established, that after carrying out of updating of a surface of samples of the carbon nanotubes by ferromagnetic iron particles reduces their adsorption-structural characteristics. | |
Keywords: | Adsorption-structural characteristics, the specific area of a surface, volume and porous radius, magnetic characteristics, modifying of surface, carbon nanotubes | |
Edition: | Nanosystems, nanomaterials, nanotehnologies. 2014, 12, №3.pp.0469-0483 | | | 2014,
0469-0483,Russian |
015 Nanodiamond Powders with High Magnetic Characteristics |
Authors: | А.Shevchenko, G.Ilnitskaya, G.Bazaly, I.Zaitseva | |
Summary: | The article presents the results of the work aimed to obtain nanodiamond powders with improved magnetic properties. It was demonstrated that an efficient way to enhance the magnetic characteristics of the nanodiamonds is modification of their surface with a ferromagnetic powder of ferric oxide. | |
Keywords: | Nanodiamond, nanomodification, x-ray fluorescence analysis, ferromagnetic powder of ferric oxide | |
Edition: | Nanoindustriya. 2014, №2, p 68-72 | | | 2014,
68-72,Russian |
015 Synthesis of nanometric iron and chromium oxide films by reactive pulsed laser deposition for photo-thermo sensors |
Authors: | S.A.Mulenko | |
Summary: | Films based on oxides of transitional metals have semiconducting properties that make them up-to-date materials for functional electronics. We deposited iron oxide (Fe2O3-X; 0 x 1) and chromium oxide (Cr3-XO3-y; 0 x 2; 0 y 2) films (thickness 50-200 nm) on <100>.Si substrate by RPLD using a KrF laser. The results show that RPLD is a very simple procedure to synthesize of iron and chromium oxide nanometric films with variable stoichiometry and, consequently, with different values of their band gap result in variable the S coefficient and the photosensitivity. The deposited films present large thermo e.m.f. coefficient and high photosensitivity that make them up-to-date materials for photo-thermo sensors. | |
Keywords: | Iron and chromium oxide films, reactive pulsed laser deposition, photo-thermo properties | |
Edition: | | | | 2011,
79960L-79967L,English |
015 Synthesis of nanometric iron oxide films by RPLD and LCVD for thermo-photo sensors |
Authors: | S.A.Mulenko, N.T.Gorbachuk | |
Summary: | Iron oxide films were deposited on <100> Si substrate by reactive pulsed laser deposition (RPLD) using a KrF laser (248 nm). These films were deposited too by the laser (light) chemical vapor deposition (LCVD) using continuous ultraviolet photodiode radiation (360nm). The deposited films demonstrated semiconducting properties. The results showed that RPLD and LCVD can be used to synthesize iron oxide thin films with variable stoichiometry and, consequently, with different values of the band gap Eg. These films have large S coefficient and high photosensitivity F and therefore can be used as multi-parameter sensors: thermo-photo sensors. | |
Keywords: | laser deposition, synthesis, oxide, film, sensor | |
Edition: | Appl. Phys. B: Lasers and Optics, v. 105, 2011, pp.517-523 | | | 2011,
517-523,English |
015 Photon synthesis of iron oxide thin films for thermo-photo-chemical sensors |
Authors: | S.A.Mulenko, Yu. N. Petrov, N.T.Gorbachuk, | |
Summary: | Ultraviolet photons of KrF-laser (248 nm) and a photodiode (360 nm) were used for the synthesis of iron oxide thin films with variable thickness, stoichiometry and electrical properties. The reactive pulsed laser deposition (RPLD) method was based on KrF-laser and the laser (light) chemical vapour deposition (LCVD) was based on a photodiode. Deposited films had semiconductor properties with variable band gap (Eg) in the range 0.43-0.93 eV. The film thickness (50-140 nm) and Eg depended on the laser pulse number, oxygen and iron carbonyl vapour pressure in the deposition chamber, and exposure time to the substrate surface with ultraviolet (UV) radiation. Sensing characteristics strongly depended on electrical and structural properties of such thin films. Iron oxide films were deposited on <100> Si substrate and had large thermo electromotive force (e.m.f.) coefficient (S) and high photosensitivity (F). The largest value of the S coefficient to have been obtained by RPLD and LCVD was about 1.65 mV/K in the range 270-290 K and in the range 280-322 K, accordingly. The largest value F to have been obtained by RPLD and LCVD was about 44 Vc/W and 40 Vc/W, accordingly, for white light at power density (I 0.006 W/cm2). It was shown that the S coefficient and F strongly depended on Eg.. Moreover these films were tested as chemical sensors: the largest sensitivity of NO molecules was at the level of 3x1012 cm-3. Our results showed that RPLD and LCVD were used to synthesize semiconductor iron oxide thin films with variable sensing properties. So iron oxide thin films synthesized by UV photons are up-to-date materials for multi-parameter sensors: thermo-photo-chemical sensors operating at moderate temperature. | |
Keywords: | photon, synthesis, oxide, film, sensor | |
Edition: | Appl. Surf. Science, v.258, 2012 pp.9186-9191 | | | 2012,
9186-9191,English |
015 Laser synthesis of nanometric chromium oxide films with high Seebeck coefficient and high thermoelectric figure of merit.Intern |
Authors: | S.A.Mulenko, N.T.Gorbachuk and N.Stefan | |
Summary: | Ultraviolet photons of KrF-laser (λ = 248 nm) were used for the synthesis of nanometric chromium oxide films with variable thickness, stoichiometry and electrical properties. The synthesis was based on reactive pulsed laser deposition (RPLD). Film deposition was carried out on <100>Si substrate in the range 293-800 K. XRD analysis showed evidence of films deposited on Si substrate had polycrystalline structure. All films demonstrated semiconductor temperature behaviour with variable band gap (Eg) less than 1.0 eV, depending on substrate temperature, oxygen pressure in the reactor and film thickness. Film thickness (55-200 nm) depended on oxygen pressure, substrate temperature and the number of laser pulses. It was found out the optimum oxygen pressure and substrate temperature when thermo electromotive force coefficient (Seebeck coefficient S) was high as 3.0-8.0 mV/K and, accordingly, the figure of merit (ZT) was high as 0.23-5.0 in the range 280-330 K. This made Cr3-XO3-Y nanometric films, synthesized by UV photons using RPLD method, an exceptionally strong candidate for effective thermo sensors and thermo converters materials operating at moderate temperature. | |
Keywords: | chromium oxides, thin films, sensors, thermo converters | |
Edition: | | | | 2014,
008-016,English |
015 Laser Synthesis of Nanometric Iron Oxide Films with High Seebeck Coefficient and High Thermoelectric Figure of Merit |
Authors: | S.A.Mulenko, N.T.Gorbachuk, N.Stefan | |
Summary: | Radiation of a KrF-laser (λ =248 nm) was used for the synthesis by reactive pulsed laser deposition (RPLD) of nanometric iron oxide [Fe2O3-X (0£x£1)] films with variable thickness, stoichiometry and electrical properties. Film deposition was carried out on <100>Si at its temperature to have being increased from 293 to 800 K. XRD analysis showed that films deposited on Si substrate had polycrystalline structure. Films demonstrated semiconductor temperature trend with variable band gap Eg about 1.0 eV or less depending on oxygen pressure, the number of laser pulses and substrate temperature. Film thickness (13-60 nm) depended on oxygen pressure, substrate temperature and number of laser pulses. The higher substrate temperature, the more crystallinity of the deposited iron oxides’ films was resulting in increasing of thermo electromotive force coefficient (Seebeck coefficient, S). It was found out the optimum oxygen pressure in the reactor, substrate temperature and film thickness when the S coefficient was high as 12-4 mV/K in the range 240-330 K. The thermoelectric figure of merit (ZT) was high as 1-6 in the range 280-330 K. This makes nanometric Fe2O3-X films, synthesized by UV photons using RPLD method, an exceptionally strong candidate for effective thermo sensors and thermo converters operating at moderate temperature. | |
Keywords: | Oxide, thin films, laser deposition, sensor, thermo converter | |
Edition: | Lasers in Manuf. and Mater. Process., v.1, 2014, pp. 21-35 | | | 2014,
21-35,English |
015 Effect of the active elements of the working environment on the electronic structure and the mechanism of deformation of the surface layers of the metal by friction |
Authors: | V. V. Tykhonovych, V. N. Uvarov | |
Summary: | The article presents the results of complex studies changes in local chemical composition and structural-phase transformations in the areas of contact interaction of bodies in sliding in different environments. It is shown that the deformation of the surface layers of metal during friction in air leads to saturation of the border areas of structural fragments of the carbon atoms that are in octahedral pore bcc iron. The carbon atoms form strong covalent bonds with the surrounding metal atoms and reduce the mobility of atoms at the borders. This contributes to strain hardening of surface layers of metal rubbing on the air and prevents its stratification on the surface friction. Plastic deformation of the surface layers of metal during friction in water leads to saturation of the border areas of structural fragments oxygen atoms, which form metastable atomic clusters Fe-O-C. These clusters and the metal atoms of the crystal lattice separate a region with low electron density, which are the result of limited participation of valence electrons in the formation of covalent bonds between metal atoms and the atoms of the clusters. Aggregation of atomic clusters Fe-O-C at the boundaries of structural fragments leads to their shift in the low transverse strain and contributes to the transition metal interacting asperities in a new structurally unstable state in which they may hydrodynamic flow without loss of continuity. This leads to the formation on the surfaces of water friction bodies the nanostructural wear-resistant layers. | |
Keywords: | Plastic deformation, distribution of impurity atoms, electronic structure, atomic Clusters, friction | |
Edition: | Progress in Physics of Metals, 2011, 12, №2: pp. 209—239 | | | 2011,
209—239,Russian |
015 Formation of nano- and ultrafine materials during friction steel |
Authors: | V.V. Tykhonovych | |
Summary: | The article presents the results of complex studies changes in local chemical composition and structural-phase transformations in the areas of contact interaction of bodies in sliding in different environments. It is shown that the deformation of the surface layers of metal during friction in air leads to saturation of the border areas of structural fragments of the carbon atoms that are in octahedral pore bcc iron. The carbon atoms form strong covalent bonds with the surrounding metal atoms and reduce the mobility of atoms at the borders. This contributes to strain hardening of surface layers of metal rubbing on the air and prevents its stratification on the surface friction. Plastic deformation of the surface layers of metal during friction in water leads to saturation of the border areas of structural fragments oxygen atoms, which form metastable atomic clusters Fe-O-C. These clusters and the metal atoms of the crystal lattice separate a region with low electron density, which are the result of limited participation of valence electrons in the formation of covalent bonds between metal atoms and the atoms of the clusters. Aggregation of atomic clusters Fe-O-C at the boundaries of structural fragments leads to their shift in the low transverse strain and contributes to the transition metal interacting asperities in a new structurally unstable state in which they may hydrodynamic flow without loss of continuity. This leads to the formation on the surfaces of water friction bodies the nanostructural wear-resistant layers. | |
Keywords: | Plastic deformation, friction, nanostructure, ultradispersive structure, pulsed thermo-mechanical effects | |
Edition: | Metallofizika I Noveishie Tekhnologii (i.e. Metal Physics and Advanced Technologies) 2011, т. 33, №12, pp. 1671-1685 | | | 2011,
1671-1685 ,Russian |
015 The role of the principle of metastability of austenite in the development of wear principle of metastability of austenite in the development of wear-resistant high-chromium cast iron |
Authors: | Tikhonovich V.I., Tikhonovich V.V., German K.Yu. | |
Summary: | The results of research, in which the effectiveness of increasing wear resistance of high-chronium cast irons due to their structure in line with other components (martensite, carbides, etc.) metastable austenite, turning under weight in the martensite (the effect of self-hardening under weight). For this it is necessary to take in account the chemical and phase composition of the alloy, as well as the conditions of wear adjust the ratio of the structural components, development of martensite transformations with wear, and also use different mechanisms of strengthening and resistance to the destruction of the alloys. | |
Keywords: | plastic deformation, wear resistance, phase transformations, the martensite, the austenite | |
Edition: | The problems of friction and wear, 2012, 58, №1: рр. 180-185 | | | 2012,
180-185,Russian |
015 The role of copper in the formation of surface friction wear resistant layers of high chrome cast iron |
Authors: | V.V. Tykhonovych, V.G. Novytskyy, V.P. Havriliuk, V.I. Tykhonovych | |
Summary: | Introduction to cast iron 120H15 the structure free copper inclusions reduces wear and friction coefficient of cast iron. The transition of friction pairs to stationary mode occurs after the formation on the contact surfaces of alloys the wear-resistant surface layers with fine grains. The main difference between the surface wear-resistant layers of cast irons 120H15 and 120H15D10 is the presence in the latter from 6.0 to 9.5 at.% copper. Despite the significant size of Cu inclusions on the friction surface of 120H15D10 cast iron any layers based on Cu are not formed. | |
Keywords: | Plastic deformation, friction, nanostructure, ultradispersive structure, pulsed thermo-mechanical effects | |
Edition: | Metal Science and Treatment of Metals, 2014, v. 69, №1: сс. 27-34 | | | 2014,
27-34,Ukrainian |
015 Study of the relaxation processes occurring on a surface of the amorphous Fe77Si8B15 ribbon by scanning tunnelling microscopy and spectroscopy |
Authors: | V. L. Karbovsky, A. G. Ilinsky, Yu. V. Lepeeva, Yu. A. Zagorodniy | |
Summary: | Methods of scanning tunnelling microscopy and spectroscopy are used to study relaxation processes occurring on a surface of the amorphous Fe77Si8B15 ribbon depending on the annealing and cooling temperatures. Influence of both temperature and heating rate on the morphology of a surface and the nanocrystals size is shown. The processes of structural relaxation observed by the method of tunnelling microscopy on a surface of the investigated alloy are described. As revealed, at moderate temperatures of annealing, nanocrystals with the characteristic size of ≈15 nm are observed. This size is comparable to a length of magnetic exchange correlation. | |
Keywords: | Scanning tunnelling microscopy and spectroscopy, clasters, nanocrystals , relaxation processes, morphology of a nanocrystals | |
Edition: | Metallofizika i Noveishie Technologii, 2012, v. 34, №1, p 99-110 | | | 2012,
99-110 ,Russian |
015 Peculiarities of atomic structure of metallic amorphous materials in temperature range from -193 to + 598оС |
Authors: | A. G. Ilinsky, Yu. V. Lepeeva, V. L. Karbovsky, G.M. Zelinskaya, T.M. Khristenko, S. S Lugovsky, A. N. Babenko | |
Summary: | The structure of amorphous Fe80Si6B14 ribbons and features of structural changes in a wide temperature range from 1900C to 5980C are studied by X-ray diffraction. Investigations are carried out on XRD diffractometer with two coordinate X-ray detector and synchroton radiation with a temperature step of 4 K. Used geometry of X-ray mode (transmission diffraction pattern) as well as very short wavelength of used radiation (0.1239 Å) provide very high intensity (statistical error of the calculation on ‘tail’ of diffraction pattern is less than 1%). The obtained data allow to conceive that crystal clusters have high rotation rate even in amorphous ribbon. The obtained data can be considered only as necessary, but insufficient for unambiguous statement. | |
Keywords: | Amorphous ribbons, nanocrystals, crystallization temperature. | |
Edition: | Metallofizika i Noveishie Technologii, 2013, т. 35, №2, сc: 145-161 | | | 2013,
145-161,Russian |
015 Problems of determining the size of the clusters in amorphous metal materials |
Authors: | Yu. V. Lepeeva, G.M. Zelinskaya, O.I.Slukhovsky, A.V. Marunyak | |
Summary: | The problems concerning determination of the clusters’ sizes in disordered (amorphous, liquid and nanocrystalline) materials are analysed. Based on the diffraction data, ways of determination of the sizes of clusters are described. As shown, until now, there is not the method of determination of such parameter. The new diffraction function f(r) allows determining the clusters’ size more precisely, because it is more size-sensitive in comparison with other diffraction-intensity functions. | |
Keywords: | Amorphous state, atomic structure, size of clusters | |
Edition: | Metallofizika i Noveishie Technologii, 2014, v. 36, №7, p 987-997 | | | 2014,
987-997 ,Russian |
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015 Nadutov Volodymyr M.Professor, Doctor of sciences (physics & mathematics) Deputy Director for Science +380444243305
015 1.3. Structure and properties of nanosystems Purpose:To establish regularities of the formation of metallic, nonmetallic and composite materials with the nanostructural and amorphous component obtained in considerably nonequilibrium conditions and to study their structure and physical-mechanical properties depending on dimension factor caused by cyclic phase transformations, thermo-mechanical influence and electromagnetic irradiation. Expected results:Release of new product: material Stage 1:Development and adaptation of methods for manufacturing and study of the materials with the ultrafine and nanostructured components and preliminary studies of their structure. Stage 2:The analysis of literature sources and patent search in the field of the studies. The study of the effect of electromagnetic irradiation and external thermal influence on state of the carbon nanotubes and detonation nanodimonds as well as the mechanical alloying, the ion-plasmous and physical deposition, the friction treatment in active environments, the martensitic transformations on phase composition and formation of nanostructures in metallic materials. Stage 3:Determination of regularities of the dimension effect on strength of a carbon nanocluster at its deformation and fracture, of the strain and irradiation fields on electron emission, of the external factors, physical-chemical processes and phase transformations on physical and mechanical properties of metallic nanostructured materials. Stage 4:Study of ordering processes of the carbon nanotubes array and cooperative dimensional effects of a quantum origin, the formation of carbon monoatomic chains, the self-organization of the surface friction layers in metals, the nanotwinning and decomposition of solid solution in martensitic phase, the diffusion mass transfer in metals with the nanostructured components, the structural change in amorphous iron-based materials at low temperatures. Stage 5:Study of mechanical and physical properties of carbon nanomaterials and metallic nanostructured alloys formed in conditions of external influences. The formulation of recommendations concerning practical application and the summarizing of the obtained results. The report preparation.
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