Glass and Ceramics最新文献

The process of manufacturing CeO₂ powders by the method of reverse deposition is investigated. The CeO₂ content in the resulting products reached 99.2 wt.%. The main phase was cerium dioxide with a cubic lattice. The average particle size of the powder was about 42 μm, and the specific surface area was about 38.6 m²/g. Heating of the material from 50 to 1200°C leads to a mass loss of 18%. This mass loss is accompanied by endothermic effects with peaks on the DTA curve at temperatures of 144, 280, and 374°C. Further research directions include optimization of the properties of the obtained material, in particular its morphology, and determination of prospective application areas.

This paper investigates the possibility of heat treatment of phosphogypsum, a waste product of the chemical industry. Partial dehydration of dihydrous calcium sulfate occurs when phosphogypsum is dried, and complete dehydration occurs when it is calcined at temperatures of 600 – 1200°C. The samples were found to actively absorb water after heat treatment below 800°C. During the heat treatment of phosphogypsum in the presence of a reducing agent, two endothermic effects related to the sequential dehydration of CaSO₄· 2H₂O were observed, as well as a broad peak of exothermic effect due to the heat degradation of the reducing agent and the formation of calcium sulfide from phosphogypsum. Heat-treated phosphogypsum samples in the presence of the reducing agent acquire the ability to emit yellow-orange luminescence under the action of ultraviolet radiation. Synthesized pigments can be used to produce water-based paints and varnishes.

The processes of thermal compaction of nanoporous glass surfaces using carbon dioxide laser radiation have been investigated. Successful formation of a thermally compacted layer with a thickness of (20 ± 1) μm was demonstrated under the following thermal compaction regime: average radiation power 10.5 W, defocusing ∆f = 16 mm of an F-theta lens with a focal length of 157 mm, scan speed 40 mm/sec, and track spacing 100 μm. It was shown that birefringent structures can be recorded through the thermally compacted layer using femtosecond pulses, with the magnitude of their phase shift serving as an indirect indicator of glass porosity.

The study presents the results of the investigation of the properties (solubility, anti-scaling, anti-corrosion, algicidal, and bactericidal) of a glassy copper-containing phosphate compounds (Cu–Zn phosphate, Cu–Zn–PC). These compounds are obtained using a zero-waste ecological technology for the purpose of corrective treatment of feed water in central heating systems. The study identifies a synergistic effect resulting from the combined presence of long-chain phosphates and alternating copper and zinc cations in the composition. This effect strengthens and evenly distributes the protective film on the surface of the system components, providing maximum effectiveness in combating scale, corrosion, and biofouling.

The chemical-mineralogical composition and technological properties of the ceramic production wastes of Kulol JSC, used as a component of the raw mix for the production of Portland cement clinker, have been extensively studied. It was found that full or partial replacement of natural clayey raw material (loess) by ceramic production wastes during firing increases the reactivity of the raw mixes, accelerates the process of CaO absorption and promotes the completion of the mineral formation process with good clinker granulation at a relatively low temperature stage — below 1450°C. Portland cement produced from synthesized clinker is classified as additive-free Portland cement CEM I according to GOST 31108–2020.

Nanoscale amorphous thin films of the (InSe)₂₀(GaSe)₈₀ and (InSe)₅₀(GaSe)₅₀ compositions were subjected to phase and elemental analysis, as well as to surface morphology studies. The optical transmission analysis of the films established their absorption to correspond to indirect allowed transitions in accordance with the Tauc model under the optical band gap values (E_g) of 1.26 and 1.07 eV for the (InSe)₂₀(GaSe)₈₀ and (InSe)₅₀(GaSe)₅₀ thin films, respectively.

Ceramics based on yttrium aluminum garnet doped with ruthenium ions were synthesized. Ceramic samples were obtained by non-reactive sintering of nanocrystalline powders formed by chemical coprecipitation. The results of XRD and EDX analysis indicated that the yttrium-aluminum garnet matrix can accommodate up to 0.5 àt.% of ruthenium cations without the formation of secondary phases or impurities. Minor deviations from the stoichiometry of the composition did not hinder the incorporation of ruthenium into the structure of yttrium aluminum garnet. In addition, changes in the valence of the sintering additive had no effect on the solubility of ruthenium ions in the ceramic material.

This paper presents the BDTR-500 robot, which is designed for crack diagnostics in silica-enamel coated pipes. The main achievements of the system include the use of GPS navigation and positioning methods, which ensure accurate location and rapid identification of emergency zones. New algorithms based on artificial intelligence and machine learning enable autonomous robot movement and high-quality data processing. High-megapixel cameras with smart lighting effectively visualize defects, while an intelligent energy management system extends autonomous operation time. Real-time data processing enables rapid damage localization and repair, and built-in sensors improve image stability on uneven surfaces. The robot can detect cracks as small as 0.1 mm. The project results confirm the high efficiency of the BDTR-500 in diagnostics and open up new possibilities for the application of this technology in pipeline monitoring and other challenging operating conditions.

This article examines the synthesis and properties of a composite ceramic material based on a glass with the composition 31.0BaO – 30.0B₂O₃ – 15.0Al₂O₃ – 7.0SiO₂ – 6.8MgO – 5.9ZnO – 4.3MgF₂ (mol.%) and an Al₂O₃ filler. The composite ceramic, prepared with an initial glass-to-Al₂O₃ mass ratio of 60 : 40 and sintered at 875°C, exhibits a relative permittivity ε_r of 8.62 and a loss tangent tan δ of 12.1 × 10 ^–4 at 1 MHz. The material demonstrates a flexural strength of 117.5 MPa, a coefficient of linear thermal expansion (CLTE) of 69.7 × 10 ^–7 K ^{– 1}, and chemical compatibility with silver electrodes. These properties suggest its applicability in low-temperature co-fired ceramic (LTCC) technology.

This study examines the influence of vacuum hot pressing (VHP) conditions on the microstructure, density, and optical properties of ZnSe ceramics. Graphite and titanium foils, as well as alumina powder, were used to isolate the compact from the graphite mold, thereby enabling the variation in carbon contamination levels. Carbon was found to significantly affect the sintering and recrystallization of ZnSe ceramics, hindering the achievement of high density and transparency. Microstructural analysis revealed that the use of alumina as an insulating layer promotes more uniform grain growth, while minimizing abnormal grain enlargement. Spectral analysis demonstrated that maximum infrared (IR) transparency was achieved in samples with initial densities exceeding 97% after additional hot isostatic pressing (HIP). However, further enhancement of the optical properties necessitates the complete elimination of carbon contamination, which demands the replacement of graphite tooling in the VHP process.