Inorganic Materials (v.46, #8)
Manganese solubility in quenched InSb by V. P. Sanygin; O. N. Pashkova; A. V. Filatov; V. M. Novotortsev (807-811).
We have studied the magnetic properties of supersaturated In1 − x Mn x Sb substitutional solid solutions prepared by quenching from the liquid state. All of the materials in the range 0.07–2 at % Mn were found to be ferromagnets. Judging from their Curie temperatures, they contained microinclusions of variable composition, similar to solid solutions based on the ferrimagnetic compound Mn2Sb at Mn contents below 0.5 at % and to solid solutions based on the ferromagnetic compound MnSb at higher Mn contents.
Etching behavior of CdTe in aqueous H2O2-HI-C6H8O7 solutions by Z. F. Tomashik; V. G. Ivanits’ka; V. N. Tomashik; L. P. Shcherbak; J. Franc; P. Moravec; P. Höschl; J. Walter (812-817).
This paper examines the dissolution behavior of the (111)A, (111)B, (110), and (100) surfaces of CdTe single crystals in aqueous H2O2-HI-C6H8O7 (citric acid) solutions. We have determined the dissolution rate of the crystals as a function of temperature and solution concentration, located the composition regions of polishing and selective etchants, and studied the microstructure and roughness of surfaces polished with optimized etchants. The etching behavior of CdTe is shown to depend on its crystallographic orientation.
Specific surface area, shape, and size of fine carbon filler particles by V. M. Samoilov (818-823).
We have studied the specific surface area, shape, and size of fine particles of isotropic and needle cokes and isotropic graphite. The results demonstrate that, as the average particle size is reduced from 1000 to 1.5 μm, the BET specific surface area of the powders increases from 0.1 to 100 m2/g, exceeding the geometric surface area of the particles by a factor of 40–60. The particle size distributions of the coke and graphite powders produced under identical milling conditions are similar to one another and can be represented by the Rosin-Rammler equation. The anisometry of the powder particles is higher at a stronger microtexture of the starting material and decreases with decreasing particle size.
Annealing effect on the structure, phase composition, and nanohardness of titanium/fullerite films by L. V. Baran (824-832).
The effect of heat treatment on the structure, phase composition, and nanohardness of titanium/fullerite films of different thicknesses produced by thermal evaporation in vacuum has been studied using atomic force microscopy, X-ray diffraction, and nanoindentation. The results demonstrate that annealing at 570 K increases the grain size of the films and leads to the formation of a Ti x C60 phase. The nanohardness of the annealed films varies little with depth owing to the interdiffusion of Ti atoms and C60 molecules.
Viscosity of Sb-Sn melts by S. I. Mudry; V. M. Sklyarchuk; Yu. O. Plevachuk; A. S. Yakymovych (833-835).
The viscosity of Sb-Sn melts containing 0, 5, 10, and 20 at % antimony has been measured as a function of temperature by the oscillating cylinder method. The composition and temperature dependences of the viscosity coefficient deviate from classical theory predictions. The anomalous behavior is interpreted in terms of melt structure and changes in short-range order. Structural changes in the Sb-Sn melts are assumed to lead to an anomalous increase in viscosity coefficient.
Structure of thermally desorbed CeNi3-based hydrides by S. A. Lushnikov; I. A. Bobrikov; A. M. Balagurov; V. P. Glazkov; V. A. Somenkov (836-841).
CeNi3H x (x = 0.7, 0.8, 1.0, 1.8, 3.4, 3.8) hydrides have been prepared through hydrogen desorption from CeNi3 hydrogenated at low (p H 2 = 0.01 GPa) and high (p H 2 = 0.2 GPa) hydrogen pressures. Using X-ray and neutron diffraction, the hydrides are shown to be isostructural with CeNi3 (sp. gr. P63/mmc, no. 194). The lattice parameters of the hydrides vary appreciably with hydrogen content. The sequence of hydrogen release from different interstices in the desorption process is shown to be opposite to that of hydrogen uptake in the hydrogenation process. The solid-solution range in the desorbed hydrides is much broader than that upon hydrogenation. The extent of the solid solution is influenced by the phase composition of the parent intermetallic compound.
Thermoelectric power factor of Ti1 − x V x NiSn alloys by Yu. V. Stadnyk; A. M. Goryn’; Yu. K. Gorelenko; L. P. Romaka; N. A. Mel’nichenko (842-846).
Ti1 − x V x NiSn (x = 0–0.10) substitutional solid solutions have been prepared by doping the intermetallic semiconductor n-TiNiSn (half-Heusler phase) with vanadium, a donor impurity, and their resistivity and thermopower have been measured at temperatures from 80 to 380 K. The results demonstrate that, when doping of TiNiSn causes no type inversion, the thermoelectric power factor of the solid solution markedly exceeds that of the undoped ternary compound.
Controlled synthesis of Cu2O micro-crystals with various morphologies by adjusting solution conditions by Long-cheng Wang; Hong Jia; Ling-yun Shi; Na Liao; Xiao-jing Yu; Da-lai Jin (847-851).
Micro-crystals of cuprous oxide with different morphologies were prepared by a hydrothermal process with copper sulfate and sodium lactate as precursors. Morphology of cuprous oxide was simply controlled by adjusting solution pH values or addition of different amounts of organic solvent. Structural properties of all the samples were characterized by X-ray diffraction and scanning electron microscopy. The growth mechanism of cuprous oxide micro-crystal under different conditions was discussed. Results show that morphologies of cuprous oxide micro-crystals alter from branched structure to octahedron structure and cube structure with growth conditions.
Composites of mesoporous Al2O3 and Fe- or Co-containing nanoparticles by T. M. Zima; N. I. Baklanova; N. Z. Lyakhov (852-857).
Composites of mesoporous alumina and Fe- or Co-containing ferromagnetic nanoparticles have been prepared from appropriate aqueous metal chloride solutions by a sol-gel process. The synthesis products were heat-treated at different temperatures in air or vacuum and then characterized by a variety of techniques. The results indicate that the mesoporous structure of the nanostructured composites has a large specific surface area, a narrow, unior bimodal pore size distribution, and high thermal stability. The phase composition of the magnetic particles in the X-ray amorphous oxide matrix strongly depends on the heat-treatment conditions.
General trends of deposit accumulation in porous hosts during cyclic impregnation with rare-earth and actinide waste solutions by A. A. Kozar (858-861).
A theoretical model is constructed to describe the dynamics of the increase in the weight of porous matrices upon introduction of rare-earth and actinide radioactive waste from solutions via repeated cycles of impregnation, drying, and high-temperature annealing. The modeling results for waste immobilization in porous Al2O3 and ZrO2 agree well with experimental data.
Visible reflection spectra of synthetic opal infiltrated with gold nanoparticles by V. S. Gorelik; L. I. Zlobina; V. A. Karavanskii; O. A. Troitskii; R. I. Chanieva (862-865).
A technique has been developed for infiltrating gold nanoparticles into the pores of synthetic opal using laser ablation and high-temperature annealing, and the reflection spectra of gold-infiltrated opal photonic crystals have been measured. When a halogen lamp was used as a broadband light source, the peak-reflection wavelength of the gold-infiltrated opal was longer than that of the uninfiltrated opal. We calculated the dispersion laws for the two lower photon bands of the synthesized photonic crystals and obtained the corresponding frequency dependences of the refractive index.
Local surface spectroscopy of magnetic photonic crystals by V. S. Gorelik; V. V. Gryaznov; N. I. Yurasov (866-869).
Visible reflection spectra of opal photonic crystals infiltrated with magnetic materials have been measured in different areas on the (111) surface of the crystals with a spatial resolution of ∼0.1 mm. The observed reflection band corresponds to the photonic band gap of the opal. The peak position of the reflection band depends on the nature of the magnetic material infiltrated into the opal pores and the position of the fiber-optic probe on the opal surface.
CaAl2Si2O8-B2Al2Si2O8-H2O (B = Na, K) zeolites by T. N. Kol’tsova (870-877).
The structures of gismondine and amicite are analyzed in comparison with one another and with those of the zeolites whose compositions lie in the hypothetical plane “CaAl2Si3O10”-Na2Al2Si3O10-H2O. It is shown that the structures are similar to each other and may undergo mutual transformations.
Multistep synthesis of metal sulfide clusters: A novel zeolite modification method by A. B. Ponomaryov; V. E. Vakhmistrov; M. V. Shostakovsky; V. N. Kalinin; E. S. Mortikov (878-884).
A general approach has been proposed for incorporating high concentrations of modifier metals into high-silica zeolites. MFI zeolites have been modified with mono- and polymetallic sulfide clusters of copper, manganese, zinc, cobalt, and nickel. The metal incorporation sequence and the nature of the anion have been shown to influence both the total content and the ratio of the modifiers in the zeolite. Using multistep syntheses, we have prepared zeolites containing superstoichiometric amounts of modifier metals. Using a variety of physicochemical characterization techniques, the zinc-containing sample has been shown to have a uniform modifier distribution. The Cu-MFI-50 and Mn-MFI-50 zeolites have been characterized by electron paramagnetic resonance and shown to contain isolated Cu2+ and Mn2+ ions stabilized on the aluminum lattice site.
Kinetics of the II → III polymorphic transformation in KNO3-RbNO3 solid solutions by E. V. Nasirov; Yu. G. Asadov (885-888).
The formation rate of polymorph III during the II → III phase transition in single crystals of the KNO3-RbNO3 solid solutions containing 2.5, 5, and 10 wt % RbNO3 has been measured as a function of temperature using optical microscopy. The formation rate is shown to increase with increasing ΔT (ΔT = T tr − T 0, where T tr is the transition temperature and T 0 is the equilibrium temperature). Best fit equations are derived for describing this process, and its activation energy is determined.
A new “invisible” IR phosphor based on yttrium and ytterbium phosphates by O. Ya. Manashirov; A. N. Georgobiani; V. B. Gutan; S. V. Semendyaev (889-895).
We describe a series of efficient “invisible” IR phosphors based on ytterbium and yttrium phosphates, differing in spectral sensitivity in the ranges 0.8–0.84 and 1.5–1.6 μm. These phosphors are of considerable practical interest and can be used in photoconversion applications and as gain media of mid-IR lasers.
Ionic conductivity of A3 − 2x Nb x Al2 − x (PO4)3 (A = Li, Na) NASICON-type phosphates by A. R. Shaikhlislamova; A. Yu. Goryainov; A. B. Yaroslavtsev (896-899).
A3 − 2x Nb x Al2 − x (PO4)3 (A = Li, Na) mixed-cation phosphates have been synthesized and characterized by impedance spectroscopy and X-ray diffraction. The synthesis temperature in the lithium system has been optimized. The steric factor is assumed to have a significant effect on the ionic conductivity of these materials.
Luminescent properties of Yb3+-doped hexagonal Ln3BWO9 (Ln = Gd, Y) by V. A. Krut’ko; A. V. Popov; Yu. K. Voronko; N. N. Chudinova (900-905).
We report the synthesis and spectroscopic characterization of polycrystalline Yb3+-doped (1, 2, and 5 at %) Ln3BWO9 (Ln = Gd and Y) borotungstates as candidate gain media for diode-pumped near-IR and visible solid-state lasers. Unpolarized luminescence and absorption spectra for the Yb3+ 2 F 7/2→2 F 5/2 transition are measured at T = 77 and 300 K, the lifetime of the 2 F 5/2 excited state is determined, and the emission cross section of the stimulated Yb3+ 2 F 5/2→2 F 7/2 transition in these compounds is evaluated. Offering a combination of nonlinear optical and lasing properties, the Ln3BWO9 (Ln = Gd, Y) hexagonal borotung-states can be used as bifunctional media for diode-pumped lasers with nonlinear laser frequency self-conversion.
Optical and electron energy loss spectra of cadmium dichloride and lead dichloride crystals by V. V. Sobolev; A. I. Kalugin; I. V. Vostrikov; E. V. Baranova; V. Val. Sobolev (906-910).
Experimental electron energy loss spectra of cadmium dichloride and reflection spectra of lead dichloride are used to calculate the complete sets of fundamental optical functions of the two highly ionic materials in a wide energy range (0–30 eV). Their cumulative permittivity and volume electron energy loss curves are decomposed into transverse and longitudinal elementary components of transitions, and their main parameters are evaluated. The effect of the nature of the cation on the key features of the optical spectra is examined.
Physical aging of chalcogenide glasses by R. Ya. Golovchak; S. A. Kozyukhin; A. Kozdras; O. I. Shpotyuk; V. M. Novotortsev (911-913).
Physical aging effects are shown to be typical of chalcogenide glasses with an under- or overconstrained network and to influence their physicochemical properties. The natural physical aging of glasses can be accelerated by gamma irradiation or exposure to light.
Extinction coefficient of Ni2+ in (TeO2)0.78(WO3)0.22 glass by G. E. Snopatin; V. G. Plotnichenko; S. A. Volkov; V. V. Dorofeev; E. M. Dianov; M. F. Churbanov (914-917).
The absorption spectra of (TeO2)0.78(WO3)0.22 glasses containing 0.01–1.0 wt % NiO have been measured at wavelengths from 450 to 2700 nm, and the spectral dependence of the extinction coefficient of Ni2+ in the glasses has been obtained. In the absorption bands centered at 810 and 1320 nm, the extinction coefficient is 20.2 ± 0.8 cm−1 (870 ± 35 dB/(km ppmw)). According to the spectral range of its absorption and its extinction coefficient, nickel is a strongly absorbing impurity in tellurite glasses. The present results can be used to formulate sound nickel concentration limits in tellurite glasses for fiber-optic applications.