Glass and Ceramics最新文献

The purpose of the study was to develop compositions of colored glasses based on basalt from the Osmonsay deposit. To synthesize glasses, compositions based on the basalt – quartz – soda lime system were studied. Quartz sand from the Samarkand deposit was used as a source of quartz. Transparent, translucent, and opaque colored glasses were obtained. The research demonstrated that it is possible to obtain glass of a wide range of colors without the use of coloring components.

The direct femtosecond laser writing of phase optical elements in glasses represents a promising technique for controlling light beams and developing new functional devices that operate on the birefringence effect. In this study, phase plates were written in the volume of silica and nanoporous glasses using a laser beam. For the first time, the chromatic dispersion curves of birefringence were measured for such plates using multiple methods. This allows the retardance of birefringent elements fabricated by direct laser writing to be estimated, even when using commercial birefringence analysis systems operating at a specific wavelength.

The study is devoted to the development of composite materials for the production of ceramic bricks based on loess-like rocks from the Suzanly deposit and waste produced by Khorazm Shakar LLC. The study examines the physical and chemical processes during firing with the introduction of amorphous silica and calcium-containing waste (beet lime) in the brick mass. The technological firing modes were determined. The objective is to develop optimal compositions of special ceramic bricks and masonry mortars for the inorganic parts of cultural heritage sites, based on local raw materials and industrial waste.

The preliminary results of experimental modeling of the impact process on a coal substance by short-pulse laser radiation are presented. During the experiments, extremely high temperatures and pressures were reached. Based on the analysis of the modified products of the target substance, coal melting was identified, followed by its cooling with subsequent solidification with the formation of glass-like carbon. The synthesis products may be of interest as novel carbon materials formed at ultrahigh pressures and temperatures, such as high-pressure carbon polymers and hollow fullerene-like structures. The results of experimental modeling can be used for comparison with naturally occurring materials in order to elucidate the mechanisms of the formation of natural high-pressure carbon substances from a non-graphite precursor.

Within the scope of the study, glasses co-doped with Sm³⁺/Gd³⁺ based on the B₂O₃–GeO₂–Bi₂O₃ system were synthesized, covering compositions of 40B₂O₃–40GeO₂–(15 – 17)Bi₂O₃–(3 – 2)Sm₂O₃–(2 – 1)Gd₂O₃ and 42.5B₂O₃–42.5GeO₂–(11.25 – 12.75)Bi₂O₃–(2.25 – 1.50)Sm₂O₃–(1.500 – 0.075)Gd₂O₃. An assessment of luminescent characteristics was carried out within the temperature range of 298 – 673 K. Spectral bands of photoluminescence associated with transitions between various Stark sublevels of Sm³⁺ ions were identified. Redistribution of the fluorescence intensity ratio corresponding to ⁴G_5/2 → ⁶H_9/2 (({uplambda }_{mathrm{PL}}^{mathrm{max}}) = 645 nm) and ⁴G_5/2 → ⁶H_7/2 (({uplambda }_{mathrm{PL}}^{mathrm{max}}) = 597 nm) transitions was observed. Based on the obtained data, calculations of the fluorescence intensity ratio FIR, as well as relative sensitivity S_R, were carried out. The obtained results indicate the promising potential of these glasses as luminescent thermometric materials.

A review of dielectric materials with high (exceeding 10,000) values of relative permittivity is presented. Most of the compositions of these materials are based on systems that include ferroelectric and non-ferroelectric components, as well as solid solutions based thereon. Various approaches to increasing the permittivity of materials are considered, including doping, sintering atmosphere, grinding time, sintering temperature, and grain size. The effect of dopants and the synthesis method on the characteristics of capacitor ceramics that can be used in the low-frequency and high-frequency range are compared.

Composite foamed inorganic materials for use as thermal insulation with a reduced thermal conductivity of 0.064 – 0.076 W/(m · K) were developed using industrial silica-containing raw materials. The influence of poreformers and hardeners on the structure, phase formation, and physico-technical properties of foamed materials was studied. It was observed that the combined use of graphite and chalk resulted in a reduction in the density of the materials, while the use of graphite and gypsum and graphite and sodium fluorosilicate led to an increase in the strength of the materials.

The adhesion strength of the solid phase boundary in the Ge₂₀Se₈₀ glass–substrate (quartz glass, stainless steel, tungsten carbide) systems was measured using the normal separation method in the temperature range of 270 – 360°C. The maximum work of adhesion of chalcogenide glass among the studied structural materials was observed for stainless steel with a non-nitrided surface. The wetting and adhesion of the Ge₂₀Se₈₀ glass melt to structural materials in the temperature range of 370 – 470°C were investigated. The maximum adhesion of the chalcogenide melt is observed for the surface of quartz glass, while the minimum is observed for the surface of nitrided stainless steel.

A method for measuring the resistive characteristics of channels in the blanks of microchannel plates was developed. Two probes were used for measurements, which minimized leakage currents through adjacent channels. The resistive properties of single channels of the microchannel insert in the reduced blank of MCP 18-10 were studied. It was established that the resistance of the channels depends on their position in the microchannel honeycomb. It was shown that the channels located in close proximity to the monolithic frame have less resistance compared to those located in the middle of a multicore glass honeycomb.