Editor’s column

A.A. Ostroushko¹, A.I. Vylkov^1,2, T.Yu. Zhulanova^1,2, O.V. Russkikh¹, M.O. Tonkushina¹, I.V. Beketov^1,3
1 Ural Federal University named after the first President of Russia B.N. Yeltsin
² Institute of High Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences
³ Institute of Electrophysics of the Ural Branch of the Russian Academy of Sciences

Abstract: As an initial sample of aluminum oxide, we used material of industrial production for the manufacture of ceramic products. Aluminum oxide powders were prepared as additives introduced into the basic material in an amount of 3% by mass obtained by electric wire explosion as well as in combustion reactions of nitrate-polymer precursor based on polyvinyl alcohol. The obtained additives were characterized in terms of the structure and particle morphology. The samples of the first type included a mixture of different modifications of aluminum oxide, the second type included hydrated aluminum oxide. The first two samples consisted mainly of unaggregated spherical nanoparticles with specific surface area of 20 and 69 m2/g, and the powder obtained in combustion reactions contained flat flake particles, it had a specific surface area of 8 m2/g. The introduction of nano-sized additives led to a shift of the dilatometric sintering curve of compacted samples to lower temperatures, up to 140 degrees maximum. The sample with the largest specific surface was more active in lowering the sintering temperature. The result obtained for the pyrolytically synthesized additive was comparable with the above-mentioned shift in the sintering curve.
Keywords: aluminum oxide, sintering, nanoscale additives, electric wire explosion method, nitratepolymer precursor combustion method

S.V. Molchanov, S.A. Tretyakov, I.A. Kaplunov, A.M. Ivanov, V.S. Stepanov, V.P. Tsvetkov, I.V. Tsvetkov, S.A. Mikheev
Tver State University

Abstract: This paper presents studies of the influence of growth conditions of paratellurite single crystals on the side surface of grown boules and the possibility of assessing the quality of crystals based on the values and dynamics of the roughness parameters and fractal parameters of juvenile surfaces. Two single crystals were grown under similar technological conditions and differing from each other in structural quality. Their lateral surfaces were studied using the optical interference profilometer NanoMap 1000WLI employing SPIP and Gwyddion softwares. As a result, roughness parameters of profiles, and fractal parameters of crystal surfaces along the growth direction were obtained,. It was concluded that under conditions corresponding to the formation of stable flows in the melt, the values of the surface roughness over the entire length of the crystal is less than 5 μm, and the fractal energy parameter can be used as a marker of the quality and homogeneity of crystals.
Keywords: paratellurite single crystals, untreated crystal surface, roughness parameters, fractal parameters

S.V. Molchanov, S.A. Tretyakov, A.M. Ivanov, I.A. Kaplunov
Tver State University

Abstract: The effect of optical treatment of the surfaces of a paratellurite single crystal corresponding to the (100), (110), and (001) crystallographic planes was studied. Using a NanoMap WLI1000 optical profilometer, the relief layer of the sample surface (paratellurite single crystal) was controlled. To study the influence of the polishing method, the process was carried out using three techniques – neutral polishing, acid polishing and alkaline polishing. The characteristics of paratellurite surfaces after grinding and polishing are determined. Conclusions are drawn about the predominant use of polishing with chemical reagents. The anisotropy of surfaces differing in crystallographic directions on the speed of grinding and polishing and on the characteristics of the surfaces is shown. Studies of the structure of ground and polished surfaces corresponding to crystallographic planes have shown that the maximum roughness height is observed for the (001) plane. The smoothest surface is achieved for surfaces coinciding with the crystallographic plane (110).
Keywords: paratellurite single crystals, optical surface, grinding, polishing, roughness

E.V. Maraeva, N.V. Permiakov, V.A. Moshnikov
Saint Petersburg Electrotechnical University «LETI»

Abstract: In a brief review, the main trends in the use at the present time of eutectic melts based on indium and gallium (EGaIn) are considered. Examples of the use of EGaIn in transistors, capacitors, electrodes, and probe systems (including those in four-probe techniques) are given. The main properties of EGaIn and the spreading of a drop of EGaIn melts are considered, and a detailed scheme of the point-contact four-probe method is given. The main issues discussed in the application of EGaIn in the field of obtaining liquid electrodes, including the formation of gallium oxides, the possibility is revealed of the influence of the spatial environment on the EGaIn droplet and manipulation of microdroplets,. It has been established that among the works of 2022-2023, a large segment is occupied by publications in the field of flexible electronics, intelligent robots, as well as wearable devices (for example, the creation of a metatissue with an antibacterial effect and the ability to be heated with a low energy consumption) and biomedical applications (the development of smart gloves for manipulating gestures, measuring the heart rate of insects).
Keywords: eutectic melts, EGaIn, liquid probes, flexible electronics

V.V. Malashenko¹, T.I. Malashenko^2
1 Donetsk Institute for Physics and Engineering named after A.A. Galkin
² Donetsk National Technical University

Abstract: The high strain rate deformation of an aged alloy with a high concentration of GuinierPreston zones is theoretically analyzed. The analysis was carried out within the framework of the theory of dynamic interaction of defects. An analytical expression for the dependence of the dynamic yield strength on the concentration of impurity atoms has been obtained. The reasons of the different influence of Guinier-Preston zones on inelastic processes at different strain rates are analyzed. It is shown that under high strain rate deformation, nanosized defects affect the nature of the dependence of the dynamic yield stress on the concentration of impurity atoms. This dependence becomes nonmonotonic and has a minimum and a maximum. The maximum corresponds to the transition from the dominant influence of the collective interaction of dislocations on the spectral gap to the dominance of the influence of the collective interaction of impurity atoms. The minimum corresponds to the transition from dominance of dislocation drag by Guinier-Preston zones to dominance of drag by impurity atoms. Numerical estimates of the contribution of the Guinier-Preston zones to the yield strength are made. It is shown that at a high concentration of Guinier-Preston zones, this contribution is very significant. Numerical estimates are made of the concentration of impurity atoms, at which the concentration dependence has a maximum and a minimum.
Keywords: high strain rate deformation, dislocations, Guinier-Preston zones, point defects, nanomaterials

N.A. Klychkov¹, V.V. Simakov¹, V.V. Efanova², I.V. Sinev^1
1 Saratov State University
² Samara State Transport University

Abstract: the temperature dependencies of the response of Cu:SnO₂ films to ethanol, 2-propanol vapours, as well as ethanol with 3% vol. background impurities of 2-prophanol in the working temperature range of 250-375°C. The aim of the study was to determine the effect of the 2-propanol background impurities on the sensor response to ethanol, as well as to assess the possibility of distinguishing a steam-air mixture containing pure ethanol vapors from a gas mixture of ethanol/2-propanole by means of single-sensor signal statistical processing. The temperature dependencies analysis of the sensor response showed that the temperature at which the maximum response is observed is individual for each substance. A selective response to substances was detected. It was found that the 3% vol. isopropyl alcohol compound decreases the response to ethanol in the tested concentration and temperature range. Statistical processing of experimental data by the principal component analysis (PCA) and cross-validation of the model by the ellipsoid and nearest-neighbor showed the fundamental ability to recognize ethanol, 2-propanol and their mixture.
Keywords: semiconductor gas sensor, detection of gas mixture, tin dioxide, temperature dependence of response, principal component analysis

I.L. Kislova, O.V. Malyshkina, P.A. Ivanova, A.I. Ivanova
Tver State University

Abstract: In this work, we obtained at various sintering temperatures and studied the ceramic samples of a 3-component system of barium niobate – calcium – strontium (Ca_0,28Ba_0,72)_0,25(Sr_0,61Ba_0,39)_0,75Nb₂O₆ (CSBN25) which is a nanostructured solid solution. The effect of sintering temperature on the structure and dielectric properties of CSBN25 ceramics was studied. It has been established that the CSBN25 sample obtained at a sintering temperature of 1300°С has the optimal ferroelectric properties. For this sample, the pore size does not exceed 10 – 100 nm, while for samples sintered at other temperatures, pores can reach 10 microns. Using examples of CSBN25 ceramics, we have also shown a direct relationship between the uniformity of the grain structure and their packing density with the dielectric properties of the samples: the maximum density and the value of the permittivity have the samples that have a dense, uniform grain structure not only on the surface, but also in the bulk of the samples. Increasing the sintering temperature of CSBN25 ceramics to1350°С leads to the appearance of an amorphous state in the sample bulk and, as a result, to a decrease in the dielectric constant.
Keywords: piezoelectric ceramics, barium – calcium – strontium niobate, lead-free materials, grain structure, permittivity

Yu.F. Ivanov¹, A.A. Klopotov², V.V. Shugurov¹, I.I. Azhazha¹, E.A. Petrikova¹, O.S. Tolkachev¹, A.V. Nikonenko^3
1 Institute of High Current Electronics SB RAS
² Tomsk State University of Architecture and Building
³ Tomsk State University of Control Systems and Radioelectronics

Abstract: Using the method of high-frequency ion-plasma sputtering (magnetron highfrequency deposition under conditions of ion-plasma assisted using a gas (argon) plasma generator «PINK») on the surface of a high-entropy CoFeCrMnNi alloy of non-equiatomic composition. Boron-containing coatings of the elemental composition Al – Mg – B and Mg – Ti – B with a thickness of 3 μm are formed. Using transmission electron diffraction microscopy, it was found that the coatings are amorphous-crystalline, i.e. contain nanosized 1.5-2 nm islands of the crystalline phase located in an amorphous matrix. It is shown that the coating deposition is accompanied by the formation in the substrate layer (high-entropy alloy) adjacent to the coating of a nanocrystalline structure with a crystallite size of 25-40 nm. At the boundaries of the crystallites, particles of iron boride of the FeB and Fe₃B compositions are revealed, which indicate the penetration of boron into the substrate. The particle size of iron boride is 5-8 nm.
Keywords: ion-plasma method, high-entropy alloy, film/substrate systems, boron-containing coating, structure, mechanical and tribological properties

A.P. Zajogin¹, N.H. Trinh², M.P. Patapovich^3
1 Belarusian State University
² Vinh University, Vinh, Vietnam
³ Belarusian State Academy of Communications, Minsk, Belarus

Abstract: The possibility was studied of creating thin-film gas-sensitive sensors using composite materials containing tin in their composition, which can significantly improve their characteristic. In addition, a layer-by-layer analysis of metals and multicomponent alloys was carried out under the action of dual laser pulses on a target in an air atmosphere. All experiments were carried out using a laser two-pulses multichannel atomic emission spectrometer LSS-1. In the course of this study, the processes of formation of a certain component composition of the near-surface laser plasma, as well as the influence of the defocusing parameter between doubled laser pulses upon their impact on the surface of the irradiated sample, were studied. Thus, this work illustrated the development of methods for obtaining nanoclusters of chemical elements during spectroscopic studies of laser plasma formed by the action of two successive pulses on a target and the possibility of obtaining nanofilms of both pure metals and composite alloys for subsequent practical application.
Keywords: gas-sensitive sensors, double laser pulses, laser plasma, layer-by-layer analysis, deposition of thin films, multichannel atomic emission spectrometry.

A.E. Doroshenko¹, V.K. Krut’ko¹, O.N. Musskaya¹, A.I. Dovnar², O.B. Ostrowskaya², Ye..M. Doroshenko², A.I. Kulak^1
1 Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus
² Grodno State Medical University, Grodno, Belarus

Abstract: Calcium phosphate coatings containing brushite, calcite, and apatite were obtained by electrochemical deposition on titanium plates at room temperature, pH 5, constant current density 30 mA/cm², from CaCO₃/Ca(H₂PO₄)₂ suspension electrolyte. A layer of amorphous apatite was deposited by the biomimetic method, by keeping the coatings in a concentrated modeling solution of Simulated Body Fluid. As a result of heat treatment at 800°C, apatite crystallized into hydroxyapatite, calcite decomposed to calcium oxide, and titanium was covered with a layer of titanium (IV) oxide. Preclinical studies on rats in vivo for 3 months showed increased osseointegration of plates with calcium phosphate coatings compared to uncoated titanium. Titanium implants with calcium phosphate coatings enriched with hydroxyapatite are promising for use in neurosurgery, dentistry, orthopedics due to the absence of inflammatory reactions from the body and increased osseointegration.
Keywords: calcium phosphate coatings, brushite, calcite, SBF model solution, apatite, hydroxyapatite