Abstract We have prepared solutions of lutetium diphthalocyanine complexes containing different concentrations of silicon carbide nanoparticles. The silicon carbide nanoparticles were spherical or quasi-spherical in shape. The size of the silicon carbide nanoparticles has been determined to be 10 nm. The optical properties of the solutions were analyzed qualitatively and quantitatively. The results

Abstract Oxyfluoride glasses in the CaF2–SiO2–B2O3–Bi2O3–Y2O3–ZnO system have been designed and prepared at various ratios of batch components, and we have studied absorption spectra and luminescence properties of Eu2O3-doped glasses. According to X-ray diffraction data, all of the glasses are X-ray amorphous. We have determined their glass transition temperature (tg). Their local structure has been

Abstract We have studied tungsten powders prepared by reducing the MgWO4 and Ca3WO6 tungstates containing 0.05–1.5 wt % phosphorus at temperatures from 700 to 800°C. The reduction of MgWO4 containing less than 0.3 wt % phosphorus was accompanied by separation of reaction products. Most of the magnesium oxide formed was located beyond the reaction zone. The tungsten powders prepared by reducing MgWO4

Abstract Cu2 – xZn1 + 0.5хSnS4 copper-deficient solid solutions with the kesterite structure have been synthesized and their unit-cell parameters have been determined for the first time as functions of composition in the range 0 < x ≤ 0.45. The 78-K cathodoluminescence spectra of the Cu2 – xZn1 + 0.5хSnS4 (0 < x ≤ 0.30) solid solutions show a band centered at 1.315 eV, which is most likely due to Zn2+VCu

Abstract The electrical conductivity σ of a series of multidomain LiNbO3:Zn,Mg crystals prepared via direct doping in the composition ranges ~1 ± 0.02 mol % MgO and ~2.8–4.6 mol % ZnO has been shown to undergo a sharp increase at T* ≈ 800 K, accompanied by anomalies in temperature dependences of their dielectric permittivity, ε(T). The largest increase in their static bulk conductivity near T* has

Abstract Equilibrium phase relations of synthetic minerals prepared by annealing metastable iron sulfides, followed by prolonged isothermal storage in the Earth atmosphere, have been studied by X-ray diffraction. The results demonstrate that prolonged storage of synthetic pyrrhotites annealed at different temperatures makes it possible to identify metastable and stable phases of Fe and S compounds

Abstract We have synthesized Fex(Cu0.5In0.5)1 – xCr2S4 solid solutions and measured their magnetization and dynamic magnetic susceptibility as functions of temperature between room temperature and liquid helium temperature in weak magnetic fields H = 100 Oe and Н~ = 1 Oe at frequencies of 10, 100, 1000, and 10 000 Hz. The results have been used to construct the magnetic phase diagram of the FeCr2S4–(Cu0

Abstract We have studied characteristic structural features of porous TiNi-based materials prepared by diffusion sintering and containing titanium additions. The results demonstrate that increasing the percentage of added titanium reduces the porosity coefficient of the material and increases the volume fraction of Ti2Ni and Ti4Ni2(O,N,C) secondary phases. It has been shown that the addition of titanium

Abstract 4H-silicon carbide ingots with high structural perfection have been grown by the modified Lely method (LETI method) on 100-mm-diameter seeds. Using our experimental data and theoretical analysis, we have systematized the key factors responsible for the degradation of the crystal structure of the ingots during the growth process. The formation of parasitic polytype inclusions in the early stages

Abstract We have studied the combustion process and the phase composition of its products using granulated 70 wt % (Ti + C) + 30 wt % (3Cr + 2C) and 80 wt % (Ti + C) + 20 wt % (3Cr + 2C) mixtures with nickel-containing binders. The results demonstrate that the addition of a nickel binder reduces the chromium content of the (Ti,Cr)C double carbide, because nickel reacts with chromium to form Nichrome

Abstract Single crystals of Ca1 – ySryRхF2 + х (R = Ho, Pr) solid solutions with high optical quality have been grown by the Bridgman technique in vacuum using a fluorination atmosphere. The thermal conductivity of the Ca0.60Sr0.40 – хHoхF2 + х solid solutions decreases from 3.27 to 2.37 W/(m K) as the fraction of holmium rises from 0 to 3 mol %, respectively. The room-temperature thermal conductivity

Abstract We have studied the effect of mechanical activation in lead ferroniobate synthesis on the formation of perovskite and pyrochlore phases during both mechanochemical synthesis and subsequent firing. It has been shown that, during mechanical activation, the first to form is the perovskite structure. During subsequent sintering of the material, the pyrochlore structure begins to form as well.

Abstract The RxBi2 – xGeO5 (R = Sm–Yb, Y) and \(\left( {{\text{R}}_{{1\,\, - \,\,x}}^{1}{\text{R}}_{x}^{2}} \right)\)BiGeO5 (R1 = Y, R2 = Pr, Nd) germanates have been prepared by solid-state reactions, by sequential firing of oxide mixtures in air in the temperature range 1003–1223 K. Their heat capacity has been determined by differential scanning calorimetry. The Cp(T) data have been shown to be

Abstract We have studied characteristic features of the reduction of single-crystal lithium tantalate and lithium niobate powders with magnesium vapor in the temperature range 1023–1123 K. The results demonstrate that the reduction of single-crystal particles is accompanied by their spontaneous mechanical disintegration. The presence of Li2O in the double oxides has not led to an increase in the specific

Abstract A method has been proposed for calculating the lattice parameter of binary substitutional solid solutions, which takes into account the presence of pressure (p) in alloys. The method has been applied to SiGe and CuAu alloys. It has been shown that, at p = 0, the deviation from Vegard’s law (Δl) results from the difference in compressibility and atomic volume between the pure constituent components

Abstract This paper presents a study of nonaqueous suspensions based on ZrO2–8 mol % Y2O3 (8YSZ) powders and describes the use of the powders for producing thin-film coatings on a La2NiO4 (LNO) substrate by electrophoretic deposition (EPD). Stable suspensions for EPD have been prepared using 8YSZ powders differing in morphology and particle size: nanopowder (YSZ_L) produced by a laser evaporation–condensation

Abstract Dense silicon carbide-based ceramic composites reinforced with SiCf fiber have been produced by hot pressing at a temperature of 1850°C. The reinforcing agent used was silicon carbide fiber produced by siliciding carbon cloth with SiO vapor. It has been shown that raising fiber content from 1 to 7 wt % increases the density, bending strength, and fracture toughness of the material, which reach

Abstract—We have studied the influence of the glycine : nitrate (G/N) ratio and heat treatment temperature on characteristics of nanocrystalline Li4Ti5O12 powders synthesized from titanium tetrabutylate and lithium carbonate via combustion of an aqueous–organic precursor, followed by heat treatment. At the optimum reactant ratio G/N = 0.7, the content of the Li4Ti5O12 phase after heat treatment of

Abstract—AgSbSe2 and (AgSbSe2)0.9(PbTe)0.1 have been characterized by X-ray diffraction, differential scanning calorimetry, and temperature-dependent electric conductivity and thermoelectric power measurements in the range 80–330 K. The results demonstrate that charge transport in both materials is due to hopping of charge carriers between localized states. We have evaluated the temperature range of

Abstract—This paper considers approaches to the preparation of potential reagents for precipitation enhancement processes. New reagents have the form of hybrid powder materials produced via physical attachment of silver iodide crystals to colloidal silica particles. In our work, hybrid powder is thought of as a combination of an inert matrix (colloidal silica) and a modifier (silver iodide as an active

AbstractThe europium gallium germanate EuGaGe2O7 has been prepared by solid-state reaction in air in the temperature range 1273–1473 K using a stoichiometric mixture of Eu2O3, Ga2O3, and GeO2. Its crystal structure has been determined by X-ray diffraction (sp. gr. P21/c, a = 7.1693(7) Å, b = 6.57008(6) Å, c = 12.7699(1) Å, β = 117.4522(5)°, V = 533.768(8) Å3). The heat capacity of polycrystalline samples

Abstract—This paper presents a topological analysis of phase equilibria in the Li2O–Al2O3–Ni–Co–O system. Using the fragmentary experimental data available, we construct isothermal phase diagrams of the Li2O–Al2O3–Nc–O (Nc = Ni + Co) and Li2O–Al2O3–NiO1 + x–CoO1 + x (0 ≤ x < 1) systems. Data are presented on phase equilibria involving Li(Ni,Co,Al)O2 (α-NaFeO2 structure), (Li,Ni,Co,Al)Al2O4 (spinel

AbstractWe have assessed the informativeness of X-ray diffraction patterns in the form of a halo, characteristic of metallic alloys prepared by liquid quenching (melt spinning) (using an Fe78P20Si2 alloy as an example) and oxide films grown on unheated substrates by ion beam sputtering of targets with an appropriate composition (LiNbO3 and Ca10(PO4)6(OH)2). Simulation results for X-ray diffraction

Abstract—We have synthesized Fe1 – xAgxCr2S4 (0 < x < 0.5) solid solutions via doping of the FeCr2S4 thiochromite with silver. From a break in the composition dependence of the unit-cell parameter for the synthesized materials, the solid solution series has been shown to be limited by x = 0.22. The magnetic properties of the solid solutions have been studied at temperatures from 4 to 300 K in a magnetic

Abstract—We have worked out conditions for the preparation of microcrystalline n-type lead telluride-based materials doped with lead iodide and investigated their microstructure and thermoelectric properties. The materials were prepared by hot-pressing powders produced by grinding an ingot to a particle size on the order of hundreds of microns in a planetary mill and to a particle size under hundreds

Abstract—We report results on frequency and temperature dependences of dielectric properties (dielectric permittivity and dielectric loss tangent) of amorphous silicon–carbon films produced using different precursors: poly(phenylmethylsiloxane) (PPMS) and poly(methylsiloxane) (PMS). It has been shown that the PPMS-based films consist of a well-defined polar dielectric, whereas the PMS-based films consist

AbstractA method for the preparation of extra-pure Na2CO3 powder has been developed. The method is based on a fractional crystallization of Na2CO3 from its saturated solutions and its conversion into sodium formate, followed by a melt crystallization. To obtain the final product Na2CO3, the recrystallized sodium formate was thermally decomposed. The contents of Th and U in the purified powder were

Abstract(Gd1 – xTbx)2O3 (x = 0.04–0.22) films 115 to 150 nm in thickness have been grown on Si and SiO2 substrates by metal organic chemical vapor deposition (MOCVD) using Ln(dpm)3 precursors. After annealing in air at 800°C for removing carbon-containing impurities, the films were sulfided in NH4SCN vapor at temperatures from 700 to 1000°C in an Ar atmosphere until the formation of (Gd1 – xTbx)2O2S

Abstract—Yttrium iron garnet (YIG) (Y3Fe5O12) films have been grown on single-crystal lithium niobate (LiNbO3) ferroelectric substrates by ion beam sputter deposition. X-ray diffraction, electron microscopy, magnetic measurement, and spin wave propagation results for the Y3Fe5O12 films suggest that they can be used in devices for mutual conversion of magnetic and electrical quantities.

Abstract—We have studied and optimized conditions for spontaneous flux growth of TbCr3(BO3)4 crystals. Phase relations in the pseudoternary system TbCr3(BO3)4–K2Mo3O10–B2O3 have been studied in the temperature range 900–1130°C and the single-phase terbium chromium borate crystallization field has been mapped out. It has been shown that increasing the TbCr3(BO3)4 content of the starting high-temperature

Abstract—This paper presents results of firing of bentonite clay, refractory clay, and metakaolin materials with NaCl additions using convective and microwave heating. Phase structures of microwave-sintered aluminosilicates have been examined and the formation of a nanometer-scale aluminosilicate structure has been demonstrated. The microwave-fired materials have been found to have an increased strength

Abstract—We have studied chemical–mechanical and dynamic chemical polishing of the surface of single crystals of PbTe and Pb1 – xSnxTe solid solutions with bromine-releasing etchants based on aqueous (H2O2 + HBr + ethylene glycol)/glycerol solutions. The rates of chemical–mechanical and dynamic chemical polishing have been determined as functions of the dilution of the basic polishing etchant with

AbstractThe PrFeGe2O7 and NdFeGe2O7 germanates have been prepared by solid-state reactions using stoichiometric mixtures of Pr2O3 (Nd2O3), Fe2O3, and GeO2 as starting oxides, which were sequentially fired between 1273 and 1473 K in air, and their high-temperature heat capacity has been determined by differential scanning calorimetry. The experimental Cp(T) data obtained have been used to evaluate their

AbstractA simple method for the preparation of a foam glass/CoFe2O4 composite material has been proposed for the first time. We have demonstrated the conceptual feasibility of utilizing glass scrap and plant ash and slag for the preparation of cellular glassy materials suitable for use as supports of catalytically active substances. The synthesized composite materials have been characterized by X-ray

AbstractThe variation in the grain size of a titanium carbide-based material with a cobalt binder is studied theoretically and experimentally in relation to its location in the chamber of a die, matrix, and along the length of the sample after SHS extrusion. Our experimental results show that the average grain size in a material synthesized without any external load is 4.9 μm. Densification in a die

AbstractWe have synthesized oxide composites based on TiO2 modified with aliovalent cations, W6+, Co3+, Cu2+, and Fe3+, in the range 5–30 wt %. Its deviation from stoichiometry is increased by active generation of Ti3+ cations during vacuum calcination at temperatures from 500 to 800°C. The photocatalytic activity (PCA) of the composites for dye degradation reactions under illumination with visible

In this review, we present analysis of absorption and circular dichroism spectra of disordered langasite crystals with the calcium gallium germanate structure, whose structures have no screw axis. We consider results of original research concerned with spectroscopic characteristics of undoped and transition metal-doped langasite crystals. Structural disordering on a site leads to charge disbalance

AbstractThis paper presents a detailed study of the magnetic and crystal structures of BaFe12 –xZnxO19 (0.25 ≤ x ≤ 1.5) Zn-substituted barium hexaferrite by Mössbauer spectroscopy, vibrating sample magnetometry, and X-ray diffraction. Partial heterovalent substitution of Zn2+ ions for Fe3+ ions demonstrates limited heterovalent isomorphism according to the scheme 2Fe3+ → Zn2+ + Fe4+, which satisfies

AbstractAlloys between tin and tin telluride have been prepared and their thermal conductivity has been measured in the temperature range ~90–300 K. We have determined the lattice (χl) and electron (χel) contributions to the thermal conductivity of the alloys and their thermal resistivity due to structural defects (Sn vacancies and defects). We assume that, at low excess Sn concentrations, Sn atoms

AbstractWe have determined the adiabatic temperature of the calcium reduction of ZrO2 and CaZrO3 (1525 and 1040 K, respectively) and the reaction onset temperature. In a mixture of reagents under an argon atmosphere in a reactor, it is about 1123 K and is determined by the calcium melting onset. If calcium particles with CaCl2 film on their surface are used as a reducing agent, reduction begins at

AbstractWe have developed a method for the preparation of boehmite (AlOOH) nanopowder with tailored properties (particle size from 10 to 40 nm, thermal conductivity below 0.02 W/(m K), specific surface area on the order of 65 m2/g, and loose bulk density in the range 0.02–0.04 g/cm3) by hydrothermal treatment of γ‑Аl2О3 nanopowder in a 1.5% HCl solution at 200°C. The steps of the process have been

AbstractWe have studied manganese-containing calcium phosphates differing in manganese content and phase composition. At a manganese content of 0.15 wt %, the whitlockite content is ~90 wt % and the calcium pyrophosphate content is ~10 wt %. Increasing the manganese content to 1.49 wt % reduces the whitlockite content to ~70 wt % and increases the calcium pyrophosphate content to ~30 wt %. IR spectroscopy

AbstractThe temperature-dependent heat capacity of vysotskite, PdS, has been determined for the first time by adiabatic, relaxation, and differential scanning calorimetry in a wide temperature range and standard thermodynamic functions of PdS have been calculated. The 298.15-K values thus obtained are = 43.65 ± 0.09 J/(mol K), S° = 51.98 ± 0.10 J/(mol K), Н°(298.15 К) − Н°(0) = 8.03 ± 0.02 kJ/mol,

AbstractEmission and visible photoluminescence excitation spectra of CaF2:Er (0.5 at %) crystals have been studied under different optical pumping conditions. The results demonstrate that anti-Stokes luminescence of the erbium-doped crystals has higher intensity in the case of pumping of the 4I13/2 metastable state of the dopant. Resonance IR photon wavelengths have been determined for two-photon excitation

AbstractA number of tetrametallic layered double hydroxides containing magnesium and cobalt on the site of doubly charged cations in the structure of brucite-like layers and aluminum and iron on the site of triply charged cations have been synthesized using three distinct methods: coprecipitation, microwave synthesis, and hydrothermal crystallization. A sodium hydroxide solution was used as a precipitant

AbstractWe have found conditions for reproducible spontaneous crystal growth of (RxLa1 –x)Al2.07(B4O10)O0.6 (R = Ce, Pr; x = 0, 0.003, 0.03, 0.5, 1) dimetaborate solid solutions. The composition and morphology of the crystals have been studied and limitations on isomorphous substitutions on the rare-earth site within the stability range of their structure type have been found out. We have studied the

Abstract—TiC + xC composites comprising titanium carbide particles, unreacted carbon black particles, and a graphite nanofilm have been prepared by self-propagating high-temperature synthesis pressing. The fused titanium carbide particles form a robust skeleton, whose voids contain carbon black particles separated from the titanium carbide particles by the graphite nanofilm. We have examined the effect

Abstract—We have studied the effect of doping with Sn (0.004 and 0.008 at %) on the properties of Bridgman-grown single crystals of an n-type Bi2Te1.5Se1.5 solid solution. Thermoelectric power, electrical conductivity, thermal conductivity, and Hall effect measurements in the range 77–400 K have shown that Sn influences the electrical transport properties of the solid solution. Single crystals with

Abstract—The β \( \rightleftarrows \) α phase transformations in foil of the Pd–52 at % Cu solid solution prepared by rolling have been studied using X-ray diffractometry and resistivity measurements during thermal heating–cooling cycles or lamp processing (LP) using light from high-power pulsed xenon lamps, followed by cooling. The results demonstrate that complete ordering of the two-phase (α + β)

Abstract—The composition and structure of a new compound, Ni3.35W9.65C4, have been determined by comparing X-ray powder diffraction, crystal-chemical modeling, and density functional quantum-chemical calculation (VASP program) results. The compound, in cast form, has been prepared by a self-propagating high-temperature synthesis metallurgy method via combustion of an exothermic WO3 + NiO + Ca + Al

Abstract—This paper describes a joint correlation analysis of the heat capacity Cp(T) and volume thermal expansivity β(T) of potassium chloride (KCl) over the entire temperature range of its solid state (from absolute zero to Tm). A trilinear model for the β(Cp) correlation dependence, consistent with experimental data and consisting of three smoothly joined linear segments, has been constructed. The

Abstract—Composites based on LiFePO4/C and poly(3,4-ethylenedioxythiophene) (LiFePO4/C/PEDOT) have been prepared via in situ oxidative EDOT polymerization or mechanical mixing of LiFePO4/C with presynthesized PEDOT particles, including those prepared in the presence of different surfactants (Triton X-100 and cetyltrimethylammonium bromide). The resultant materials have been characterized by X-ray diffraction

Abstract—The structure and typical behavior of boron–oxygen groups in Li2O–B2O3 melts and glasses have been studied by high-temperature Raman spectroscopy. Under conditions similar to those of lithium triborate crystal growth, we have detected the formation of BO2 monomers, which influence the growth process. The results have been compared to those for structural groups of pure boron oxide.

Abstract—We have optimized conditions for the flux growth of the RAl3(BO3)4 (R = Y, Nd, Gd, Lu) and RMgB5O10 (R = Y, La, Gd) rare-earth borates and measured the thermal conductivity of YAl3(BO3)4, NdAl3(BO3)4, GdAl3(BO3)4, LuAl3(BO3)4, and LaMgB5O10 crystals. The results strongly suggest that these materials are potentially attractive for use as laser gain elements.

Abstract—The Bi12TiO20, Bi4Ti3O12, and Bi2Ti4O11 bismuth titanates have been prepared by solid-state reactions, via multistep firing of stoichiometric mixtures of their constituent oxides in air at temperatures from 1003 to 1273 K (Bi12TiO20, to 1123 K). The heat capacity of polycrystalline samples of the synthesized compounds has been determined by differential scanning calorimetry in the temperature

Abstract—A LiNbO3:Zn (4.69 mol % ZnO) crystal grown from a charge synthesized using homogeneously doped Nb2O5 as a precursor has been shown to contain less luminescence centers in comparison with a LiNbO3:Zn (4.60 mol % ZnO) crystal prepared via direct doping. In the case of LiNbO3:Zn crystals prepared via direct doping, the intensity of all luminescence bands varies monotonically as the ZnO concentration

Abstract—Colloidal Cd1 –x(Ca,Sr)xS and Cd1 –xCaxS:Eu3+ (0 < x < 0.20) quantum dots (QDs) have been synthesized by an emerging reagent method in a methylmethacrylate (MMA) medium. The mole fraction of Eu3+ in the starting reaction mixtures was varied from 0 to 0.80 relative to the Ca2+ concentration. Using radical block polymerization of MMA, we have obtained transparent luminescent polymethylmethacrylate

Abstract—The heat capacity Cp(T) of cadmium fluoride, strontium fluoride, and the Cd0.5Sr0.5F2 solid solution has been studied experimentally (2–300 K). We have detected deviations ΔCp(T) of the Cp(T) data from additivity. The low-temperature (2–50 K), positive deviations ΔCp(T) have been tentatively attributed to the effect of two-level systems associated with the glasslike character of the low-temperature

Abstract—It has been shown that two competing processes occur in a system of water glass (WG) silicates and [BnXn]2– (n = 10, 12; X = H, Cl) boron cluster anions (WG/[An]) in the range 100–200°C: the formation of a supramolecular structure due to cation–anion contacts of the silanol groups of the silicate with [An]'s at t ≤ 100°C and the condensation of the silanol groups of the silicate, resulting

Abstract—The use of magnetic fields in nonaqueous spent nuclear fuel treatment processes involving molten salts opens up new possibilities for selective extraction of radionuclides. In this research, this approach has been applied to the selective extraction of rare-earth elements and zirconium. We have studied strontium hexaferrite and a spinel ferrite as a magnetic carrier, examined the feasibility