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The oxidation resistance of ultra-high-temperature ceramic material (HfB2-30 vol%SiC)-2 vol%rGO (rGO: reduced graphene oxide) under long-term exposure (2000s) to a supersonic air flow has been studied. The ceramics were obtained by reactive hot pressing of HfB2-(SiO2-C)-rGO composite powder at a temperature of 1800°C (pressure 30 MPa, holding time 15 min, Ar). The surface temperature of graphene-modified ceramics under the influence of heating by high-enthalpy air flow (heat flow q reached 779 W·cm–2) did not exceed 1700°C, which is 650–700°C less than for the HfB2-30 vol%SiC baseline ceramics. This may be related to an increase in the efficiency of heat transfer from the sample to the water-cooled module, due to the higher thermal conductivity of the rGO-containing material. Thereby, a decrease in the material degradation degree has been noted, i.e. decrease in the recession rate and decrease in the total thickness of the oxidised ceramic layer by tenth. The peculiarities of the oxidised surface and near-surface region microstructure upon aerodynamic heating of the graphene-modified ceramic material, have been shown.

Nanopowders of the compositions BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) and BaCe0.9 – xZrxY0.1O3 – δ (x = 0, 0.5, 0.6, 0.7, 0.8) were synthesized by the combined crystallization of nitric acid salts and the citrate-nitrate method. Those nanopowders were used to produce ceramic materials with a cubic crystal structure of the perovskite type, with a grain size of ~20–70 nm. The study of electrophysical properties revealed that they have a proton type of conductivity in the temperature range of 500–700°C; σ = 10–2–10–5 S/cm. The type and mechanism of electrical conductivity of ceramics of the composition BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) were studied both experimentally and using theoretical calculations by computer modeling using the electron density functional method; the results are in good agreement. The research shows the prospects of using the obtained ceramic materials as proton-conducting electrolytes for solid oxide fuel cells.

MnOx thin films on various types of substrates (glass, quartz, alumina, and Pt/Al2O3/Pt) were prepared by a combination of the sol–gel method and pen plotter printing, using the hydrolytically active heteroligand complex [Mn(C5H7O2)2 – x(C4H9O)x] as the precursor. The effect of synthesis parameters and printing modes on the microstructure, optical and electrophysical properties of the manufactured planar nanomaterials was studied. The electron work function of the MnOx film surface was assessed by Kelvin probe force microscopy (KPFM). Impedance spectroscopy was used to determine the temperature-dependent electrical conductivity of the prepared films in the temperature range 325–500°С. The proposed synthetic method and printing technology show promise for the formation of thin-film manganese oxide nanostructures for supercapacitor electrodes and optical devices.

Nb2O5–TiO2 nanomaterials containing 0.5 and 10 mol % TiO2 have been synthesized by the programmed deposition method. The products have been characterized by modern physicochemical methods The Nb2O5–TiO2 nanomaterials have a crystal structure of orthorhombic Nb2O5 (T-phase). Individual niobium oxide is composed of nanoparticles with an average size of 15 ± 3 nm; increasing the TiO2 content entails microstructural changes. For the Nb2O5–TiO2 coatings, a set of chemoresistive gas-sensing properties has been studied. Of all the analyzed gases, the highest sensitivity was recorded for oxygen and hydrogen sulfide. It has been shown that the sample with 5% TiO2 is most sensitive to О2 and H2S, which is explained by the formation of additional oxygen vacancies.

—The preparation of zinc sulfide nanoparticles by chemical deposition was studied. The thermal behavior of the thus-prepared nanopowder in air at temperatures in the range 25–500°C was examined by simultaneous thermal analysis. The product was identified using X-ray powder diffraction and IR spectroscopy. Transmission electron microscopy (TEM) was used to determine the sizes of the product nanoparticles. Functional ink based on the prepared zinc sulfide was used to form thick-film ZnS nanostructures by microextrusion printing. Scanning electron microscopy was used to study the microstructure of the thus-formed coatings, and their electrophysical properties were assessed by impedance spectroscopy. Microextrusion printing was found to be effective not only in bioprinting, but also in the formation of semiconductor coatings.

Comparative structural and thermal investigations of a process of formation of nanocrystalline lead zirconate titanate Pb(Zr0.50Ti0.50)O3 (PZT 50/50) powders, with a tetragonal structure, prepared via a gel combustion route under different thermal treatment conditions, were conducted. The thermal behaviour of a gel and an as-formed combustion product (powdered precursor) was studied using TGA/DTA techniques. The XRD study of the powdered precursor calcined at various temperatures, in combination with the TGA/DTA data, resulted in the establishment of the optimal temperature mode for obtaining a single-phase PZT 50/50 nanopowder. A possible mechanism for the formation of the PZT 50/50 phase during gel combustion has been proposed. Formation of a single-phase PZT powder with a given molar ratio of Pb/Zr/Ti = 1/0.5/0.5 was verified by XRD, μ-XRF and EDS methods. The results of XRD and FTIR spectroscopy indicated the tetragonal crystal structure of the PZT powder. The nanocrystalline nature of PZT 50/50 was confirmed by both XRD and SEM data. SEM studies revealed that the prepared nanopowders had a homogeneous, porous, coral-like microstructure with an average grain size in the range of 90–100 nm. According to the simultaneous thermal analysis (TGA/DSC) results, thermal stability of the PZT 50/50 nanopowder was observed up to 1000 °C. Local capacitance and the distribution of its values were measured on the surface of the PZT 50/50 coating, formed on Pt/Al2O3/Pt substrate using the screen printing technique, using scanning capacitance microscopy (SCM).

The effect of the addition of cerium acetylacetonate on the solvothermal synthesis of zinc oxide nanopowder, a promising receptor material for chemical gas sensors, was studied. The obtained products were characterized by DSC/TGA, X-ray powder diffraction analysis, Raman spectroscopy, and scanning and transmission electron microscopy. It was found that an increase in the content of the cerium acetylacetonate additive causes a shift of the maximum of the exothermic event in the DSC curves toward lower temperatures (from 323 to 277°C). The produced ZnO powders have a hexagonal crystal structure of the wurtzite type; no cerium-containing phases were observed. The unit cell parameters of ZnO nanopowders were calculated by the full-profile X-ray phase analysis. It was shown that an increase in the [Ce(O2C5H7)2] leads to noticeable changes in the microstructure of the products.

The solid solution Ba0.5Sr0.5Co0.8Fe0.2O3 – δ was synthesized by the glycol–citrate method. The thermal behavior of the obtained powder was studied by simultaneous thermal analysis in an air flow in the temperature range of 25–1200°C, and the conditions were determined for the heat treatment to obtain the oxide with a given cubic crystal structure of the perovskite type. The obtained powder was assayed and its phase composition and microstructure were investigated by a set of modern methods of physicochemical analysis (X-ray powder diffraction analysis, energy-dispersive X-ray spectroscopy, and IR spectroscopy). It was shown that the proposed synthesis method under the determined conditions is efficient for obtaining the single-phase oxide of the given composition without impurities.

Abstract The process of glycol-citrate synthesis of nanodispersed oxide with the composition La0.6Sr0.4Co0.2Fe0.8O3 – δ have been studied. The resulting nanopowder has been examined using a complex of modern methods of physicochemical analysis. The thermal behavior of the obtained powder in air in the temperature range of 20–1000°C has been investigated using synchronous TGA/DSC analysis. As a result, the optimal conditions for the sample heat treatment have been determined, to lead to the formation of a single-phase nanocrystalline oxide. Using X-ray diffraction analysis, IR spectroscopy, and energy-dispersive X-ray spectroscopy, it has been shown that the proposed synthesis method is convenient and effective for obtaining a highly dispersed powder of the specified composition with the target crystal structure. Scanning electron microscopy has been applied to analyze the morphology of the oxide nanopowder and determine the average particle and pore size.

Nanocrystalline TiO2 powder with an average crystallite and particle size of 11.6 ± 1.2 and 36 ± 2 nm, respectively, having anatase structure, has been prepared by the sol–gel method. The powder has been used for pen plotter printing of semiconductor coatings on a special sensor. The sensor surface has been modified with copper-containing nanoclusters using the AACVD method, and the elemental composition of the resulting composite coatings has been studied by the EDX method. TiO2 and TiO2:Cu receptor nanomaterials showed a high reproducible response to H2S at an operating temperature of 300°C. Copper doping of the TiO2 surface contributed to a significant increase in the response to high concentrations of H2S (the RAir/R response by 100 ppm H2S increased from 44.2 to 70.5) probably due to the formation of CuS groups on the surface of the receptor material. The modification of TiO2 with copper oxide led to a decrease in the oxygen sensitivity apparently because of a decrease in the number of active oxygen vacancies involved in the detection of oxygen.

The formation process for planar solid electrolytes in the CeO2-Y2O3 system has been studied using efficient, high-performance, high-resolution microplotter printing technology, using functional ink based on nanopowders (the average size of crystallites was 12–15 nm) of a similar composition obtained by programmed coprecipitation of metal hydroxides. The dependence of the microstructure of the oxide nanoparticles obtained and their crystal structure on yttrium concentration has been studied using a wide range of methods. According to X-ray diffraction (XRD), the nanopowders and coatings produced are single-phase, with a cubic crystal structure of the fluorite type, and the electronic state and content of cerium and yttrium in the printed coatings have been determined using X-ray photoelectron spectroscopy (XPS). The results of scanning electron (SEM) and atomic force microscopy (AFM) have shown that the coatings produced are homogeneous, they do not contain defects in the form of fractures and the height difference over an area of 1 µm2 is 30–45 nm. The local electrophysical characteristics of the oxide coatings produced (the work function of the coating surface, capacitance values, maps of the surface potential and capacitive contrast distribution over the surface) have been studied using Kelvin-probe force microscopy (KPFM) and scanning capacitive microscopy (SCM). Using impedance spectroscopy, the dependence of the electrophysical characteristics of printed planar solid electrolytes in the CeO2-Y2O3 system on yttrium content has been determined and the prospects of the technology developed for the manufacture of modern, intermediate-temperature, solid oxide fuel cells have been demonstrated.

Information about the surrounding atmosphere at a real timescale significantly relies on available gas sensors to be efficiently combined into multisensor arrays as electronic olfaction units. However, the array's performance is challenged by the ability to provide orthogonal responses from the employed sensors at a reasonable cost. This issue becomes more demanded when the arrays are designed under an on-chip paradigm to meet a number of emerging calls either in the internet-of-things industry or in situ noninvasive diagnostics of human breath, to name a few, for small-sized low-powered detectors. The recent advances in additive manufacturing provide a solid top-down background to develop such chip-based gas-analytical systems under low-cost technology protocols. Here, we employ hydrolytically active heteroligand complexes of metals as ink components for microplotter patterning a multioxide combinatorial library of chemiresistive type at a single chip equipped with multiple electrodes. To primarily test the performance of such a multisensor array, various semiconducting oxides of the p- and n-conductance origins based on pristine and mixed nanocrystalline MnOx, TiO2, ZrO2, CeO2, ZnO, Cr2O3, Co3O4, and SnO2 thin films, of up to 70 nm thick, have been printed over hundred μm areas and their micronanostructure and fabrication conditions are thoroughly assessed. The developed multioxide library is shown to deliver at a range of operating temperatures, up to 400 °C, highly sensitive and highly selective vector signals to different, but chemically akin, alcohol vapors (methanol, ethanol, isopropanol, and n-butanol) as examples at low ppm concentrations when mixed with air. The suggested approach provides us a promising way to achieve cost-effective and well-performed electronic olfaction devices matured from the diverse chemiresistive responses of the printed nanocrystalline oxides.

Thermodynamics of boehmite formation upon hydrothermal treatment of micron-size particles of hydrargillite and γ-Al2O3 at 200°C in various media has been studied at various treatment times. The presence of surface-bound water with low evaporation enthalpy value at the initial stages of precursor hydrothermal treatment has been revealed. It has been shown that, irrespective of precursor and hydrothermal treatment medium, the prepared boehmite has similar properties

A hierarchical nickel oxide film was grown on the surface of a polycrystalline Al2O3 substrate by hydrothermal synthesis. The microstructure of the obtained coating was studied by scanning electron microscopy and atomic force microscopy, which showed that this coating comprises porous nanosheets (about 7 nm thick) arranged at various angles to each other and to the surface of the substrate. The lateral sizes of these nanosheets were in the range 3–5 μm. The local electrophysical characteristics of the obtained oxide coating were investigated by scanning capacitance microscopy and Kelvin probe force microscopy; using the obtained results, the maps of the distributions of the surface potential and capacitance contrast over the surface of the NiO film were constructed, and the work function of the surface of this film was calculated.

The formation of a hierarchical cobalt(II, III) oxide coating on the surface of a polycrystalline Al2O3 substrate under hydrothermal conditions was studied. Features of the microstructure of the obtained coatings were investigated by scanning electron microscopy; these coatings were shown to consist of Co3O4 nanosheets arranged perpendicular to the surface of the substrate with a blossoming flower-like structure. The production of the coating of the desired composition without crystalline impurities was confirmed by IR spectroscopy, X-ray powder diffraction analysis, and energy dispersive spectroscopy elemental analysis. The roughness of the formed Co3O4 film was estimated by atomic force microscopy. The local electrophysical characteristics of the produced oxide coating (work function of film surface, capacitance, and surface distribution maps of surface potential and capacitance contrast) were studied by scanning capacitance microscopy and Kelvin probe force microscopy. A local analysis of the current–voltage characteristics of the studied samples was made.

One-dimensional h-MoO3 structures were produced by a hydrothermal method. The effect of the hydrothermal treatment conditions on the microstructure and particle size of the formed oxide powder was shown. The formation of the hexagonal structure of the powder and the absence of crystalline impurities were confirmed by X-ray powder diffraction analysis. The electrophysical characteristics of the surface of the obtained powder were evaluated by scanning capacitance force microscopy and Kelvin probe force microscopy. The kinetics of the visible-light photocatalytic degradation of rhodamine B in the presence of h-MoO3 was studied.

(In2O3)0.95(SnO2)0.05, (TbOх)0.50(Y2O3)0.50, and (CeO2)0.80(Y2O3)0.20 single-phase cubic solid solution xerogels and nanocrystalline powders have been synthesized via coprecipitation of hydroxides. Using these powders as precursors, nanoscale film electroconductive materials on a corundum substrate have been produced by screen printing. The highest speed of sensor response to ozone is attributed to In0.95Sn0.05O1.5 films, reaching 8–10 s at a temperature of 473 K. (TbOх)0.50(Y2O3)0.50 thin film is found to be sensitive to changes in the concentrations of (CO + CO2) (the sensitivity coefficient S = 25.11) and ozone (S = 3.16–7.94). (CeO2)0.80(Y2O3)0.20 film exhibits a sensor response to (CO + CO2) (S = 3.10). This study opens up the prospects of using the obtained nanopowders and relevant thin films as materials for resistive gas sensors operating at oxygen pressures of 103–104 Pa.

Nanopowders and thin films of (СeO2)1-x(Y2O3)x composition (x = 0.10, 0.15 and 0.20) were obtained by the sol-gel process, using hydrolytically active complexes of the metal alkoxoacetylacetonate class [M(C5H7O2)3-y(C5H11Oi)y] (M = Ce3+ and Y3+) as precursors. The impact of the chemical composition and crystallization conditions on the microstructure, electrophysical and chemosensory characteristics of the obtained planar-type solid electrolytes was studied. The prospects of the thin-film nanostructures obtained as receptor components of resistive oxygen sensors, as well as of electrolytes of planar-type intermediate-temperature solid oxide fuel cells (SOFC) have been shown. It has been found that (CeO2)0.90(Y2O3)0.10 thin films demonstrate the maximum values of electrical conductivity (550 °C) and the highest sensory response when detecting oxygen (concentration range 1–20%, operating temperature range 300–450 °C).

The process for preparing SnO2 nanocrystalline microspheres via synthesis in microemulsions combined with hydrothermal treatment of the resulting suspensions was studied. Tin acetylacetonate, whose n‑butanol solution is more convenient for use compared to classical reagents, was shown to have a promise for use as a precursor. Simultaneous thermal analysis and IR spectroscopy showed the transformation of a hydrated powder under heating to yield anhydrous tin dioxide. SEM analysis of the prepared SnO2 powder microstructure elucidated a two-level organization of oxide particles—nanoparticles with a size of about 25 nm were hierarchically organized in the form of medium-sized microspheres of about 1.5 µm, were formed during microemulsion synthesis upon tin acetylacetonate hydrolysis.

Hierarchical nanostructures based on rodlike particles of the composition CeO2–10% Y2O3 were obtained by programmed direct coprecipitation of metal hydroxides in the presence of polyvinyl alcohol. The effect of the concentration of the structure-forming polymer template on the morphology of the formed oxides was shown. The dependence of the particle size and microstructure of the products on the polyvinyl alcohol concentration in the reaction system was identified. Simultaneous thermal and X-ray powder diffraction analyses determined that the polymer during precipitation is incorporated into the structure of the produced nanopowder, preventing coarsening of particles during heat treatment.

Nickel oxide nanosheets were manufactured using sol–gel technology and hydrothermal treatment. The effect of hydrothermal treatment on the hierarchical organization character of the thus-manufactured oxide powder was shown. The microstructural parameters of the powder were studied by transmission (TEM) and scanning (SEM) electron microscopy; The homogeneity of the powder and the absence of impurities of another chemical composition were verified by energy dispersive elemental microanalysis (EDX).

Using a citrate-nitrate process, BaCe 0.9-x Zr x Y 0.1 O 3-δ (x = 0, 0.5, 0.6, 0.7 and 0.8) nanopowders were synthesized, on the basis of which proton-conducting solid electrolytes (average size of coherent scattering region (CSR) - 15–53 nm) were obtained by spark plasma sintering (SPS) at a low temperature (900°С). The dependence of phase composition, microstructure and electrophysical properties of the obtained samples on ZrO 2 content and consolidation conditions was established. It was found that the BaCe 0.4 Zr 0,5 Y 0.1 O 3-δ solid solution had the highest electrical conductivity among zirconium-containing ceramic materials in the studied concentration range. It was shown that SPS is a promising method for obtaining solid electrolytes for proton-conducting solid oxide fuel cells (PCFC) at lower temperatures (by 400–500°С), compared to traditionally-used temperature conditions (1400–1800 °C).

We have applied spark ablation technology for producing nanoparticles from platinum ingots (purity of 99.97 wt. %) as a feed material by using air as a carrier gas. A maximum production rate of about 400 mg/h was achieved with an energy per pulse of 0.5 J and a pulse repetition rate of 250 Hz. The synthesized nanomaterial, composed of an amorphous platinum oxide PtO (83 wt. %) and a crystalline metallic platinum (17 wt. %), was used for formulating functional colloidal ink. Annealing of the deposited ink at 750 &deg, C resulted in the formation of a polycrystalline material comprising 99.7 wt. % of platinum. To demonstrate the possibility of application of the formulated ink in printed electronics, we have patterned conductive lines and microheaters on alumina substrates and 20 &mu, m thick low-temperature co-fired ceramic (LTCC) membranes with the use of aerosol jet printing technology. The power consumption of microheaters fabricated on LTCC membranes was found to be about 140 mW at a temperature of the hot part of 500 &deg, C, thus allowing one to consider these structures as promising micro-hotplates for metal oxide semiconductor (MOS) gas sensors. The catalytic activity of the synthesized nanoparticles was demonstrated by measuring the resistance transients of the non-sintered microheaters upon exposure to 2500 ppm of hydrogen.

The formation of NiO nanosheets (average CSR size is 10.4 nm) through the hydrothermal method using a heteroligand complex of composition [Ni(C5H7O2)2-x(C4H9O)x] as a precursor was studied. Using the obtained oxide nanopowder and pneumatic microextrusion printing, NiO coating was applied to the surface of a specialized Pt/Al2O3/Pt chip, and chemosensor properties were investigated in the detection of various gases. It was determined that when CO, NH3, H2, and NO2 were detected, the conductivity of the NiO coating changed from p- to n-type with increasing temperature. Using XPS, XRD, and Raman spectroscopy, it was found that upon exposure to H2S, the surface of NiO coating partially undergoes irreversible chemical modification with the formation of nickel sulfide, resulting in a significant change in the sensory properties of the coating. It was shown that the formed receptor material exhibits the greatest response when detecting H2S, and the proposed approach, combining hydrothermal synthesis and printing technology, is promising for the creation of modern components of resistive gas sensors.

Using (СeO2)1-x(Y2O3)x (x = 0.10, 0.15 and 0.20) nanopowders obtained by co-precipitation of metal hydroxides with elements of cryotechnology, and consolidated using the SPS method, intermediate-temperature solid electrolytes with an appropriate composition were obtained; (the average size of CSR was 48–62 nm, ρrel – 83–93%). The dependence of the phase composition, microstructure and electrotransport properties of the samples obtained on Y2O3 content and consolidation conditions was established. It was shown that the solid solution (CeO2)0.90(Y2O3)0.10 had the highest ionic conductivity, at 550 °C, in the СeO2–Y2O3 system. It was established that SPS is a more efficient method of obtaining nanocrystalline solid electrolytes for IT-SOFCs, in comparison with conventional approaches.

Nanopowders with a composition of (СeO2)1–x(Gd2O3)x (x = 0.03, 0.05, 0.07, and 0.10) are synthesized by the coprecipitation method using cryotechnologies. The coherent scattering region (CSR) of the powders is 10–14 nm and the specific surface area is 70–81 m2/g. Based on the powders, ceramic nanosized materials with CRS of 64–71 nm are obtained. The dependence of the phase composition, microstructure, and electrical transport properties of the obtained samples on the Gd2O3 content is established. In a CeO2–Gd2O3 system, a solid solution with the composition of (CeO2)0.90(Gd2O3)0.10 has the highest ionic conductivity with the transfer number of ions of ti = 0.74 at a temperature of 700°C. It is shown that ceramics of this composition can be used as a solid electrolyte of intermediate-temperature fuel cells due to their physicochemical characteristics.

This paper reports on activities carried out as part of a pre-conservation studies of the painting by Dmitry Levitsky, “The Portrait of F.P. Makerovsky in a Masquerade Costume” (1789, the State Tretyakov Gallery). Samples were taken and prepared for further study within the following algorithm. Using optical microscopy of cross-sections of the samples taken, structural elements of layered compositions were revealed and external differences between them were established. X-ray fluorescence spectroscopy was used to evaluate the elemental composition of the painting surface and cross-sections of samples. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy was used to clarify the elemental composition of each of the structural elements of the samples taken, their submicro- and microdimensional inclusions, to map the distribution of chemical elements over the studied surface, and to determine the dispersion of organic and inorganic components contained in the material. Micro-FTIR was used to identify functional groups and to determine the main classes of inorganic compounds, as well as binders, used, including in the local analysis of micro-inclusions. The list of specific chemical compounds in the composition of the studied paint layers and grounds, which included an examination of the varnish coating, was determined with micro-Raman spectroscopy using data obtained by the above methods. As a result of the study, complementary information was obtained on the chemical composition of the inorganic components used, of the binder and of the varnish coating, which is required for further conservation of this work of art.

Nb2O5 powder obtained by programmable precipitation was used to form a thick gas-sensing film as part of a chemoresistive gas sensor, by screen-printing. The coating of orthorhombic Nb2O5 consisted of nanoparticles with a size of 41.0 ± 2.5 nm. XPS revealed Nb5+, Nb4+ and Nb2+ as well as oxygen vacancies in the crystal structure of niobium oxide. As a result of studying the chemoresistive gas-sensing properties of Nb2O5, it has been shown that among the analysed gases (H2, CO, NH3, H2S and О2), the greatest sensitivity was observed for oxygen and hydrogen sulphide. Nanocrystalline niobium oxide showed a high and reproducible response to 0.02–20% О2 (S1 = 1.1–19.0) at a very low detection temperature of 200 °C for oxygen sensors. At an operating detection temperature of 250 °C, a high and reproducible response to low concentrations of hydrogen sulphide of 4–100 ppm (S2 = 1.2–6.6) was detected for Nb2O5. The influence of humidity on the received signals when detecting oxygen and hydrogen sulphide was studied in detail: there was a decrease in the resistance and the response value at 95% humidity in the medium of both gases. However, unlike the process of detecting H2S (when the response of S2 was almost lost), when determining oxygen, the response of S1 was reduced by a factor of two only, which suggests the possibility of determining the content of O2 in high humidity conditions.

Сombining the sol–gel method and pen plotter printing, using the hydrolytically active heteroligand complex [Co(C5H7O2)2-x(C4H9O)x] as a component of a new functional ink, Co3O4 thin films were produced on the surface of substrates of various types. The influence of synthesis conditions and print modes on the microstructure, optical, electrophysical and sensor properties of planar nanomaterials was comprehensively studied. The optical band gap energies associated with charge transfer for transitions O2-→Co3+ and O2-→Co2+ of the obtained thin films were evaluated. Using Kelvin probe force microscopy and impedance spectroscopy, the electrophysical characteristics (the electronic work function of the film surface, the temperature dependence of electrical conductivity, and the activation energy of electrical conductivity) of the obtained Co3O4 films were determined. The sensitivity of printed cobalt(II, III) oxide thin films with respect to various gases (Н2, СН4, СО and NO2) was studied. It was established that the obtained samples demonstrated the highest sensor response when detecting CO and NO2 in the operating temperature range of 150–200°С. The prospects of the proposed synthesis method and printing technology when forming Co3O4 thin-film nanostructures to create electrodes of supercapacitors and receptor components of resistive CO and NO2 gas sensors were shown.

A sol-gel method with aluminium and yttrium alkoxoacetylacetonates as precursors was used to modify highly dispersed silicon carbide powder, with the formation of SiC@Y3Al5O12 with a low content of Y3Al5O12 ∼2 vol%. Two series of porous silicon carbide-based ceramics were produced by spark plasma sintering (SPS) of SiC and SiC@Y3Al5O12 powders at temperatures of 1,400–1,700°С (exposure time 5 min) and sintering pressures of 47 and 58 MPa. The relative density was 38–51 and 26–49% for materials obtained without and with modification, respectively. It was shown that the greatest influence of the sintering additive on the compaction process was observed at elevated SPS temperatures of 1,600–1,700°С. This was related to easier sliding of SiC particles during high-temperature sintering, due to the formation of a liquid Al2O3-Y2O3-SiO2 film on their surface under given temperature conditions. A significant (by 2.5 times) increase in compressive strength for modified samples, compared to ceramics obtained based on an individual, highly dispersed SiC powder, was observed at the maximum SPS temperature (1,700 °C); the microhardness value rose sharply (by 5.9 times) at an SPS temperature of 1,600 °C. The effect of sintering pressure increase at an SPS temperature of 1,500 °C was not so significant, and this was mainly observed for samples obtained by liquid-phase sintering of SiC@Y3Al5O12.