Vol 44, No 3 (2018)

Glasses of the system 75TeO₂–20ZnO–5La₂O₃–0.8Tm₂O₃–xYb₂O₃ were prepared by high temperature melt cooling method. Results of differential scanning calorimetry indicate that, all glass samples have excellent thermal stability. Judd–Ofelt strength parameters, spontaneous emission probabilities, fluorescence branching rations, fluorescence radiative lifetime of Tm³⁺ ions in tellurite glass were calculated. The impact of Yb³⁺ concentration on the fluorescence properties of Tm³⁺ ions in the S band under the pumping wavelength of 465 nm was investigated in a suggestion that, ³H₄ radiative lifetimes will be prolonged and the performance of optical amplifier gain of Tm³⁺ in tellurite glass co-doped with 0.5 mol % Yb³⁺ ions will be improved.

Thin films of hydrogenated silicon carbide (SiC_x:H) and carbonitride (SiC_xN_y:H) are synthesized in a reactor with inductively coupled RF plasma with the introduction of tetramethylsilane vapors and additive gases—argon and/or nitrogen. The process is carried out at different synthesis temperatures, plasma power, and partial pressure of tetramethylsilane and additive gases in the reactor. The dependences on the synthesis conditions of the films’ growth rate, chemical composition, and properties such as the light transmission coefficient, refractive index, optical band gap, and dielectric constant are obtained. The weak dependence of the films’ composition and properties on the preset synthesis conditions is a characteristic feature of the studied process within the investigated range of conditions. The possible reasons of this phenomenon and the results of in situ studies of the gas phase composition in the plasma are examined.

Solid solutions in In₂O₃–MeO₂ (Me = Zr, Sn, Ti) systems based on indium oxide are synthesized by the coprecipitation method. It is found that the ultrasound treatment of the coprecipitation products reduces the degree of agglomeration of the initial particles by a factor of 3 and initiates the crystallization process of the precipitates. Nanocrystal (5–8 nm) precursor powders are obtained at 400°C. The optimal regime for sintering powders based on In₂O₃ to form a ceramic with a dense microstructure is chosen. The influence of the temperature, alloying additives, and the partial pressure of oxygen on the specific conductivity of indium oxide solid solutions is studied.

The results of the experimental study of glass of the xFe₂O₃–(100–x)[40ZnO. 60B₂O₃] composition in which the content of iron oxide varies from 0 to 10 mol % are presented. The regularities of the glass structure change in the short- and intermediate-range order structures are considered based on the data of infrared spectroscopy and Raman spectroscopy. The valence and coordination state of iron in a glass matrix is studied by Mössbauer spectroscopy.

Borosilicate glasses of two compositions are synthesized and investigated with the aim of preparing glass microspheres from them. Using the Appen and Okhotin additive methods, the physicochemical properties of the glasses and melts are calculated, their crystallization ability and water stability are experimentally studied, their intrinsic temperatures are determined using dilatometry and differential scanning calorimetry, and their TLCE values are obtained.

A glasslike material of the 35Bi₂O₃ · 40PbO · 25Ga₂O₃ composition is investigated. Quartz glass is used in the synthesis as the crucible material. It is shown that, compared to the platinum crucible, the high-energy transmission cutoff shifts from 650 to 500 nm, which has enabled us to study the upconversion luminescence spectra of the glass of the 35Bi₂O₃ · 40PbO · 25Ga₂O₃ composition doped by Er³⁺ ions in the range 500–700 nm. The upconversion luminescence spectra for the glass doped by Er³⁺ and codoped by Nd³⁺ and Yb³⁺ ions are obtained.

The main conditions for obtaining decorative glass and glassy-crystalline materials from technogenic raw materials (overburden rocks, enrichment wastes, by-products of processing ores and concentrates, wastes of chemical industries) are considered. Relationships between the composition of the secondary raw materials and a number of important technological properties are established. The compositions and conditions of the production of decorative glass and glass with special properties made of technogenic raw materials from Murmansk region are developed. The efficiency of the compaction of glass batches is studied and the increase in the melting speed of the tableted batch and the clarification rate of the glass mass are experimentally observed.

The results of calculating the three-dimensional fields of elastic stresses induced by the local heating of glass on condition that it is cut by ytterbium laser radiation with a wavelength of 1.07 μm and lying within the range of the weak absorption of soda-lime glass. An extended area in the form of a tensile stress streak forms on the surface of the glass along the beam’s line of movement under the laser glass irradiation. It is restricted on both sides by compressive-stress zones obstructing the crack from passing beyond the tensile stress region. It is demonstrated that the most favorable conditions for the stable propagation of the crack are realized when using two spots of irradiation.

The fabrication of ceramics from nano-dispersed chrome oxide powder is investigated. Fine-grained (150–200 nm), compact, and strong ceramic samples of a microhardness of 8.3 GPa are obtained by the spark plasma sintering method.