Glass and Ceramics最新文献

Influence of the specific surface area and filler concentration on the coefficient of linear thermal expansion (CLTE) of sintered composites based on high lead fused glass and lead titanate was investigated in order to obtain solder materials offering unusually low CLTE values. The microstructure of compositions was investigated by optical microscopy methods in combination with birefringence testing with a localization of about 1 μm. In samples containing up to 55% PbTiO₃ powder having a specific surface area of less than 560 cm²/g, near-zero and even negative values have been achieved.

Phosphate glasses with a high concentration of Nd³⁺ ions are key components for the development of efficient near-infrared (NIR) laser systems. The sensitization of Nd³⁺ ion luminescence in BaO–P₂O₅ glass using Ag nanoaggregates is investigated in this study. The results show that the thermally stimulated formation of ({text{Ag}}_{m}^{n+}) molecular clusters allow a 15-fold enhancement of the photoluminescence intensity of Nd³⁺ ions, whereas the formation of plasmonic nanoparticles (NPs) did not achieve such an enhancement. These results open new perspectives for controlling the properties of phosphate glasses and improving the efficiency of laser systems.

The main types of defects in ceramic blanks and the causes of their occurrence are considered in this article. Comparative analysis of two materials—duralumin alloy and caprolon—used in the manufacture of cores is presented. The influence of passive forming surface materials of the core on the quality characteristics of quartz ceramic products is estimated. The possibility of using of caprolon, which has water-absorbing properties and does not require the use of lubricants for the production of quartz ceramic products by the slip-casting method, to reduce the occurrence of technological defects of ceramic blanks to 25%, is demonstrated.

Chemical elements capable of contaminating high-purity crystalline, ceramic and glass materials used in the production and research of photonic and electronic devices have been identified. Sources of pollution included street air during the spring and summer seasons, as well as airborne particles resulting from construction activities, various personal care products, protective gloves, and cleaning materials. Possible measures for reducing uncontrolled pollution are proposed.

LuAG-based optical ceramics co-doped with Yb³⁺ and Er³⁺ ions was successfully synthesized for the first time. The optical, spectral-luminescent, and kinetic characteristics of ceramics based on Y_2.82Yb_0.15Er_0.03Al₅O₁₂ (YAG 5-Yb, 1-Er) and Lu_2.82Yb_0.15Er_0.03Al₅O₁₂ (LuAG 5-Yb, 1-Er) compositions were investigated. It is demonstrated that excitation of luminescence at a wavelength of 940 nm in YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics results in the effective transfer of excitation radiation energy from Yb³⁺ ions to Er³⁺ ions. The energy transitions that play a pivotal role in the processes of Stokes and anti-Stokes luminescence of ceramics based on YAG 5-Yb, 1-Er and LuAG 5-Yb compositions was identified, and a schematic representation of these transitions is presented. The mutual variation of the intensity of anti-Stokes luminescence bands resulting from the transitions ²H_11/2 → ⁴I_15/2 (525 nm) and ⁴S_3/2 →⁴I_15/2 (546 nm) was observed, with regard to the power of the excitation radiation. This study demonstrates the potential of YAG 5-Yb, 1-Er and LuAG 5-Yb, 1-Er ceramics as materials for optical thermometry.

By means of vibrational spectroscopy, the study examines the structure of matrix materials synthesized through the quenching of sodium-rubidium aluminoborosilicate melts with the addition of zirconium. Zirconium was found to have a significant effect on the ratio of the main structural units and the distribution of modifier cations among them in the glass structure. The obtained results were used to explain changes in the glass-melt transition temperature and synthesized material density; they can be useful in adjusting the composition and synthesis parameters of matrix materials for the immobilization of high-level radioactive waste containing significant amounts of zirconium.

The possibility of increasing the current density of a charged particle beam (focusing) by means of tapered glass channels without the use of external energy sources is actively translated into action today for positively charged ions. For electron beams, this possibility is not realized due to the lack of experimental data on the sliding interaction between electron beams and a dielectric surface. It is necessary to examine the compression of an electron beam by tapered capillaries depending on their geometrical parameters, as well as to study the temporal characteristics of the focusing process. In this work, the authors experimentally studied the compression of a 10 keV electron beam using a 15-mm-long tapered glass channel with an inlet-to-outlet inside diameter ratio of 1.15 mm/0.30 mm. The beam current density is shown to increase at the outlet of the capillary with the specified parameters by up to a factor of 2.7 for the position where the channel axis is parallel to that of the initial beam. This density increase is estimated for electrons that have lost no more than 1 keV of initial energy. It is also shown that the process of electron transmission by a tapered capillary is stable regardless of the orientation of the capillary with respect to the direction of the initial beam.

The article shows the possibility of synthesizing a ZnO-based sulfur chemisorbent deposited on a granular (upgamma -{text{AI}}_{2}{text{O}}_{3}) substrate by impregnating it with an aqueous zinc salt solution followed by thermal decomposition. The strength and textural properties of the obtained sorbent were studied via low-temperature nitrogen adsorption, x-ray diffraction, and scanning electron microscopy. The synthesized adsorbent exhibits higher strength and more efficient use of the surface than conventional ZnO-based sorbents used in natural gas processing. The proposed sorbent showed relatively high static sulfur capacity for ({text{H}}_{2}text{S}) adsorption as compared to industrial zinc-based counterparts.

The compliance of buildings with fire safety requirements is an urgent issue for design engineers and builders. Based on the analysis of statistical data, the inadequacy of measures to ensure the safety of individuals in case of fire and the role of translucent fire-rated glazing (FRG) in solving this problem are substantiated. Mandatory fire safety requirements for FRG of buildings are considered. Regulatory documentation is analyzed in the context of recent updates of regulations on fire safety requirements. A brief review of fire-rated glazing and fire-rated glass is presented. Recommendations are given on the use of fire-rated glazing to increase the safety of individuals in the event of fire.

The paper outlines the principles of the directional drilling method with the use of hydraulic fracturing, demonstrating the impact of drilling cuttings and coal combustion waste on the environment. It presents the results of physical and chemical analysis of drilling cuttings from the Vostochno-Chumakovskoye oil field and boiler slag from the OGK-2-Novocherkassk SDPP Branch. In addition, the potential use of boiler slag in the synthesis of aluminosilicate proppants is investigated.