Glass and Ceramics最新文献

The study examines the effect of varying yttria (Y₂O₃) content, used as a stabilizing dopant, on the micro-structure, phase composition, and mechanical properties of zirconia (ZrO₂)-based ceramics fabricated by electron-beam sintering under forevacuum conditions. Samples with Y₂O₃ concentrations ranging from 1.8 to 31.5 wt.% were investigated. An increase in the proportion of yttria in the initial mixture resulted in a decrease in the density of the sintered ceramics, while simultaneously promoting the stabilization of the tetragonal ZrO₂ phase. This phase stabilization enhanced the strength characteristics of the material, even in the absence of applied pressure during sintering. The highest microhardness, reaching 5.64 GPa, was achieved at a concentration of 15 wt.% Y₂O₃.

A ceramic composite was synthesized using β-CaSiO₃ (wollastonite) with perovskite additives and an Al₂O₃–CuO–Li₂CO₃ sintering aid. This study examines the influence of sintering additives on the ceramic and dielectric properties of both CaSiO₃/Al₂O₃–CuO–Li₂CO₃ and CaSiO₃/CaTiO₃–Al₂O₃–CuO–Li₂CO₃ systems. The thermal conductivity λ of the obtained samples ranged from 0.43 to 0.65 W/(m ∙ K), which is characteristic of wollastonite ceramics. The relative dielectric permittivity ε_r ranged from 4.9 to 8.0, the dielectric loss tangent (tan δ) was (15.3–17.9) × 10 ^–3 at a frequency f of 1 MHz, and the average density ρ_av was 2.44 – 2.63 g/cm³. Sintering was carried out at temperatures ranging from 875 to 950°C. The combination of these properties, along with low thermal conductivity λ, meets the criteria for thermally stable ceramic packages and substrates used in low-temperature co-fired ceramic (LTCC) microelectronics applications.

In this work, we set out to develop a laser-induced breakdown spectroscopy (LIBS) method for monitoring the homogeneity of optical glasses in terms of chemical composition. A quantitative LIBS-based method for studying lead distribution over the surface area of lead silicate glasses is proposed. The parameters of laser radiation acting on the surface of lead silicate glasses (pulse energy, laser pulse repetition rate, laser wavelength, delay between the pulse and the analytical signal registration) are optimized. The minimum step of scanning the chemical composition over the surface area of a sample was established to be 300 μm.

The restoration of natural ecosystems is among the most urgent contemporary challenges, demanding prompt and effective solutions. In light of severe and widespread environmental pollution, active remediation efforts have become imperative. One of the most promising strategies for recycling drilling waste involves its conversion into value-added materials, such as proppants, ceramics derived from drill cuttings (shlamolite), and ceramic stones (keramsten). Beyond improving waste management, repurposing drill cuttings as a raw material could reduce industrial demand for virgin natural resources. This paper presents the physical and chemical analyses of drilling waste and evaluates its potential for the synthesis of high-performance aluminosilicate materials.

This study examines the spectral and luminescent properties of zinc phosphate glasses in the ZnO–P₂O₅ (PZ) system, doped with 0.25 – 1.00 mol.% Er₂O₃. An increase in the Er₂O₃ content results in an intensification of the luminescence band centered at approximately 1537 nm. We evaluated the phenomenological Judd–Ofelt intensity parameters (Ω_t, where t = 2, 4, 6) and calculated the corresponding radiative transition probabilities, branching ratios, stimulated emission cross sections, and radiative lifetimes of the excited state. The obtained results demonstrate the potential of the studied material as an active medium for near-infrared (NIR) emission.

This study examines the dielectric properties and total harmonic distortion of lead zirconate ceramics sintered at varying temperatures using PbO and ZrO₂ nanopowders with particle sizes of 500 nm and 20 nm, respectively. The use of nanoscale powders resulted in a decrease in sintering temperature in comparison to conventional ceramics fabricated from 1 μm particles. The highest dielectric permittivity was observed in samples sintered at 1100°C. A decrease in permittivity was recorded at sintering temperatures exceeding 1200°C. However, cooling within the 226 – 208°C range induced the formation of a ferroelectric phase.

Silica-based adsorbents incorporating organylsilsesquioxane fragments bearing organic radicals were synthesized for application in the adsorptive separation of oxygen-argon mixtures via pressure swing adsorption (PSA). Synthesis followed a base sol-gel protocol involving directed co-condensation of a reagent mixture. The materials were characterized using thermogravimetric analysis and low-temperature nitrogen adsorption. The presented results detail the oxygen and argon adsorption properties of the synthesized adsorbents. The sample functionalized with (diethylaminomethyl)silsesquioxane groups exhibited the greatest selectivity for argon. This material exhibited the greatest total volume of micropores and mesopores alongside a broad pore size distribution within the mesoporous range.

This study examines the feasibility of utilizing tailings from the beneficiation of banded iron formations (BIF) within the Kursk Magnetic Anomaly (KMA), along with waste from vanadium production, for the plasma synthesis of pigmented structural glass (PSG). Key design features of a specialized plasma glass-melting furnace are also outlined. The operational properties of the synthesized glass were evaluated, including its water resistance, frost resistance, microhardness, and phase composition. The color characteristics of the material were determined in the CIE L^*a^*b^* color space.

This study examines the physical and mechanical properties of corundum ceramics fabricated from domestically sourced G-00 grade alumina. The optimal mechanical strength was achieved in ceramics sintered at 1450°C with the addition of 5 wt.% yttrium oxide and 5 wt.% of a eutectic MnO–TiO₂ additive. The findings indicate the feasibility of import substitution of alumina.

This study presents the chemical and mineralogical characterization of hematite from the Kyzyltash deposit, both prior to and following calcination. Methods for its beneficiation were selected. Red and brown pigments were synthesized, and their phase composition and microstructure were subsequently analyzed using x-ray diffraction and electron microscopy. An investigation was conducted into the coloring properties of the obtained red and brown pigments. The results indicate that hematite from the Kyzyltash deposit can be used as a raw material component in the production of ceramic glazes and color pigments at construction material enterprises in Uzbekistan.