AbstractThe results of research on the production of porous glass materials for thermal insulation based on silica-containing technogenic waste and nepheline are presented. The effect of modifying additives on the physical and technical properties of foamed materials is studied, and their optimal quantity and ratio are determined. It is shown that the introduction of a mixture of chalk and gypsum into the charge can significantly increase the strength (by a factor of 1.8–2) and reduce the water absorption of foam glass materials.

AbstractA geometric and topological analysis of the crystal structures of Li68Ge16-oC84 (a = 4.551 Å, b = 22.086 Å, c = 13.275 Å, V = 13.275 Å3, Cmcm), Li44Ge24-oC68 (a = 4.380 Å, b = 24.550 Å, c = 10.540 Å, V = 1144.11 Å3, Cmcm), and Li12Ge12-tI24 (a = b = 4.053 Å, c = 23.282 Å3, I41/amd) intermetallic compounds is carried out. For the Li68Ge16-oC84 intermetallic compound, two new frame-forming clusters are found: K12 = 0@12(Li9Ge3) with symmetry m in the form of linked 5-rings Li3Ge2 and Li4Ge, with the Li atoms located in the center of the 5th rings, and K9 = 0@9(Li3Ge)(Li3)2 with symmetry m in the form of linked 3рrings (Li3)(GeLi2)(Li3). For the Li44Ge24-oC68 intermetallic compound, two new frame-forming clusters are established: K11 = 0@11(LiLi5)(Ge5) with symmetry m in the form of 5-ring Ge5 (lying at the base of the pyramid), which are coupled with the 5-atoms of Li, lying in the same plane with the Li atom (top of the pyramid) and K6 = 0@6(GeLi5) with symmetry m in the form of double tetrahedra Li3Ge having a common edge LiGe. For the Li12Ge12-tI24 intermetallic compound, the frame-forming cluster K6 = 0@6(Ge3Li3) with symmetry 2 is found in the form of double tetrahedra Li2Ge2 having a common edge LiGe. The symmetry and topological code of the processes of self-assembly of Li68Ge16-oC84, Li44Ge24-oC68, and Li12Ge12-tI24 crystal structures of cluster-precursors are reconstructed in the following form: primary chain → layer → framework.

AbstractThe SiO2, Gd2O3–SiO2 and Eu2O3–SiO2 were synthesized by two ways: using the silicon oxide isolated from kaolin and using the silicon oxide obtained by hydrolysis of tetraethoxysilane. Agar-agar (polysaccharide) was added as a structure-forming agent and the freeze-drying was used for obtaining powders. DSC and TG up to 700°С revealed endothermic effects corresponding to the loss of free moisture, the decomposition of metal hydroxide and hydroxogroups (≡Si–OH) from the silica surface. The powders calcined at 700°С are X-ray amorphous. The morphology of the samples was studied using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The hydrodynamic size of the particles synthesized from kaolin, determined using DLS method, exceeds the particle size established by TEM. The hydrodynamic size of the nanoparticles obtained from tetraethoxysilane is within the particle size determined by TEM. The agglomerates formed by particles synthesized from tetraethoxysilane are less strong than those obtained from kaolin. In the Eu2O3–SiO2 system obtained using tetraethoxysilane, nanocrystallinity with a particle size of 8–40 nm was detected. The luminescence excitation spectra for the Eu2O3–SiO2 samples synthesized by both ways differ in the ratio of the supersensitive 5D0–7F2 and magnetodipole 5D0–7F1 transition bands. For the Gd2O3–SiO2 nanopowder obtained from tetraethoxysilane, an increase in the 5D0–7F2 intensity, as well as the appearance of a second 5D0–7F1 peak were observed.

AbstractThe results of studies on the intensification of the dealkalization process of alkaline silicate industrial and synthesized glasses with acid gases are analyzed and summarized. The composition of the reaction products of glasses with gaseous reagents is identified using X-ray phase analysis, X-ray spectral electron probe microanalysis, thermal analysis, flame photometry, and quantitative chemical analysis. The physicochemical properties of industrial glassware modified with gaseous reagents are determined in laboratory and factory experiments. Ways of intensifying the dealkalization process of silicate glasses with acid gases are discussed.

AbstractThe effect of In incorporation is studied on the, micro-hardness compactness and elastic properties of glassy Se–Te–Cd alloys. The micro-hardness of glassy Se75Te15 – xCd10Inx (x = 0, 5, 10 and 15) alloys is calculated at room temperature. The compactness structure of Se75Te15 – xCd10Inx alloys is also determined from the measured densities. The micro hardness is maximum for glassy Se75Te5Cd10In10 alloy and compactness minimum for same concentration. The volume of the micro-voids, their formation energy and the module of elasticity are determined using the free-volume theory and are considered in terms of average coordination number ❬Z❭.The module of elasticity E is increases in starting with average coordination number reach maximum then decreases and the micro-void volume Vh is minimum for glassy Se75Te5Cd10In10 alloy.

Abstract—This short communication presents an approach to obtaining a deep, up to several tens of micrometers, surface relief in photosensitive silicate glasses. The approach is based on a local change in the resistance of glasses to chemical etching due to their crystallization. Under the action of a laser beam, a region is formed in photosensitive glasses, in which, after heat treatment, nuclei of the crystalline phase are formed, and local crystallization occurs. During subsequent etching, the crystalline regions are etched faster, and this provides the formation of surface relief, with the relief pattern being set by a laser beam, which makes it possible to avoid “wet” lithography. The formation of grooves up to 50 µm deep in photosensitive silicate glasses has been experimentally demonstrated.

AbstractSamples of a series of homogeneous solid solutions Sr3–xB2Si1–xO8–3x:yEu3+ (x = 0.63, y = 0.001, 0.01, 0.1, 0.2, 0.4) were obtained by crystallization from the melt. Investigations were carried out by X-ray phase analysis and thermal analysis. The unit cell parameters and the melting and crystallization temperatures of solutions were determined.

AbstractTo improve the characteristics, samples of diamond–carbide silicon composite were subjected to microwave processing. The products were placed in a microwave oven chamber, in a zone with maximum electric field intensity. As a result of processing, it was possible to increase the density of samples by 7%, as well as reduce porosity by more than an order of magnitude.

AbstractGlasses with compositions of stoichiometric and nonstoichiometric (with an excess of lithium oxide) Li-aegirine (LiFeSi2O6), as well as nonstoichiometric Li-aegirine with the addition of carbon and copper, are synthesized. The processes of the formation of crystalline phases and their evolution during the heat treatment of initial quenched glasses in the temperature range of 600–1100°C are studied by X-ray diffraction analysis. The phase composition of the initial glasses is different: the stoichiometric Li-aegirine glass contains cubic nanocrystals of magnetite, Fe3O4, ~ 21 nm in size, formed during the casting and quenching of the initial glass. An increase in the quenching rate leads to diminishing the magnetite crystal size to ~ 8 nm and to a decrease in their number. Glasses of nonstoichiometric composition are X-ray amorphous. The X-ray diffraction analysis of the crystals formed during the heat treatment of quenched glasses in a gradient furnace showed that, in all glasses at temperatures of 700 to 1040°C, crystals of monoclinic Li-aegirine (space group С2/c) are formed. At heat treatment temperatures above 1040°C, incongruent melting of Li-aegirine occurs with the formation of cristobalite and/or magnetite. The obtained results will form the base for the development of an electrode material for lithium-ion batteries (LIBs).

AbstractUsing computer methods (ToposPro software package), a combinatorial topological analysis and modeling of the self-assembly of Zr72P36-oS108 (a = 29.509 Å, b = 19.063 Å, c = 3.607 Å, V = 2029.49 Å3, Cmmm), Zr18Ni22-tI40 (a = b = 9.880 Å, c = 6.610 Å, V = 645.23 Å3, I4/m, and Zr4Ni4-oS8 (a = 3.271 Å, b = 9.931 Å, c = 4.107 Å, V = 133.43 Å3, Cmcm) crystal structures are carried out. For the crystal structure of Zr72P36-oS108, 40 variants of the cluster representation of the 3D atomic net with the number of structural units 5, 6, and 7 are established. Structural units in the form of a pyramid K5 = 0@PZr4, tetrahedron K4 = 0@Zr4, and supratetrahedron K9 = Zr(Zr4P4) of four connected tetrahedra. For the crystal structure of Zr18Ni22-tI40 also defined supratetrahedra K9 = Ni(Zr4Ni4) are defined. For the crystal structure of Zr4Ni4-oS8, the tetrahedral cluster precursor K4 = Zr2Ni2 is defined. The symmetry and topological code of the processes of self-assembly of 3D structures from cluster precursors is reconstructed in the following form: primary chain → layer → framework.

AbstractThe change in the resistive characteristics of lead silicate glasses (LSGs) after treatment in alkaline and acid solutions is studied. It is established that the chemical treatment of glasses and, accordingly, blanks of microchannel plates (MCPs) affects the high-temperature ionic conductivity at a constant activation energy of electrical conductivity. It is shown that the treatment of glasses in NaOH and HF solutions can significantly change the electrical resistance.

AbstractBased on the data obtained by complex methods of physicochemical analysis on studying various sections of ternary Tm–As–S(Se) systems and using the published data, the boundary of the glass formation region of the Tm–As–S and Tm–As–Se system is determined. It is established that at a cooling rate of 10 deg/min in the Tm–As–S system, the glass formation area of the system’s glass is 33 at % of the total area of the triangle; and at a cooling rate of 102 deg/min, 51 at % of the total area of the triangle. In the Tm–As–Se system under the specified cooling regimes, the glass area is 35 and 54 at %, respectively.

AbstractIn this paper, for the first time, an experimental study is conducted of phase equilibria in two three-component NaCl–NaBr–Na2CO3 and NaCl‑NaBr‑Na2SO4 salt systems. The compositions and temperatures of points of interest for the creation of functional materials are established. Projections of phase complexes onto composition triangles include two fields of crystallization: sodium carbonate (sodium sulfate) and a solid solution of NaClxBr1–x. Phase equilibria are described for crystallization fields and monovariant curves.

AbstractThe valence state and local environment of atoms in Ge3Sb2Te6, Ge2Sb2Te5, GeSb2Te4, and GeSb4Te7 amorphous and crystalline films are determined by Mössbauer spectroscopy (MS) on isotopes 119Sn, 121Sb, and 125Te. In crystalline films, divalent germanium is located in octahedral positions in a rhombohedrally distorted NaCl-type of lattice, whereas in amorphous films, tetravalent germanium atoms form a tetrahedral system of chemical bonds. In all films, the nearest environment of germanium contains predominantly tellurium atoms. Trivalent antimony atoms in crystalline and amorphous films occupy two types of octahedral positions differing in the degree of distortion, and in the nearest environment of antimony there are tellurium atoms. Finally, in all films, the local structures of tellurium atoms correspond to tellurium structural units in the GeTe and Sb2Te3 compounds.

AbstractBox-counting approach based on the analysis of particle number distribution between separate fragments of electron micrographs is applied to composites based on cyanoethyl ester of polyvinyl alcohol containing barium titanate (BaTiO3) filler nanoparticles modified by the deposition of small layer graphene nanoplatelets. This modification is shown to significantly affect the microstructural characteristics of the composites, including the filler distribution uniformity, lacunarity and fractal dimension. The obtained data are compared with the increase in permittivity of the composites resulting from the filler modification with graphene.

AbstractGlass composition of 6Na2O 22B2O3·70SiO2·2Cr2O3 is studied by scanning electron microscopy, X‑ray powder diffractometry (XRPD), and differential thermal analysis, depending on the duration of heat treatment at a temperature of 550°C. It is established that during heat treatment for 24–96 h, a phase separation structure with interpenetrating phases is formed in the studied glass, and a crystalline phase of eskolaite—Cr2O3 is also formed. With the maximum heat treatment duration of 96 h, cristobalite is formed in the bulk of the glass, which is accompanied by a decrease in the glass transition temperature of the low-viscosity phase. In this case, the intensity of eskolaite peaks decreases. Cr2O3 and SiO2 crystallize apparently due to the substance of the low-viscosity phase.

AbstractIn this paper, the possibility of saturation of the surface of the powder of steel grades X6CrNiTi18-10 and 40NiCrMo4 with alloying elements using chemical-thermal treatment by the gas transport method was studied. Ammonium chloride and iodine were tested as a transport agent. The results of the transport of titanium, aluminum, manganese and chromium are shown. To compare the corrosion resistance of coatings according to GOST 9.308-85, specimens in the form of plates were studied.

Abstract—The morphology of particles of aluminum-magnesium montmorillonite of different chemical compositions, synthesized under conditions of stepwise hydrothermal heat treatment of gels in the range from 200 to 300°C is studied. The morphologies of particles synthesized under the conditions of static and stepwise heat treatment are compared. The possibility of obtaining particles with spherical and spongy morphologies with different porosities, depending on the heat treatment conditions and the chemical composition of montmorillonite, is shown.

AbstractThe physicochemical processes occurring in glasses of the PbO–CdO–SiO2–B2O3–Al2O3 system after high-temperature contact with oxides of various metals—CuO, NiO, Al2O3, TiO2, Nb2O5, and WO3, as well as the electrical resistance of the obtained glasses—are studied by X-ray phase analysis, infrared spectroscopy, and electron paramagnetic resonance. It is established that these properties are determined by the acid-base and redox properties of the oxides and glasses, which directly depend on the content of the O2– ion in each specific composition.

AbstractThe study of the mechanical properties of materials is of considerable fundamental and practical interest to most scientists. In this work the values of the equilibrium cell parameter, bulk modulus, its first derivative with respect to the pressure, and the speed of sound for diamond were calculated using the density functional theory (DFT) method and are 3.570 Å, 433.2 GPa, 3.71 and 17731.2 m/s. These parameters are found to be in good agreement with the experimental ones. The results of the study show that the mechanical properties of materials can be predicted with a high precision using the DFT method.