Glass and Ceramics最新文献

This study investigates the surfaces of lead-silicate glasses and unetched blanks of microchannel plates following mechanical processing. The immersion of the prepared samples in a 33% H₂O₂ solution increased their optical transparency, while concurrently reducing their mass. We attribute these effects to the removal of organic and organosilicon surface layers formed during mechanical processing.

This study presents a novel approach to the sustainable reuse of mineral waste in ceramic glaze production from Shoushan stone processing residues. The research highlights their synergistic role in regulating the coloring mechanism and optimizing glaze layer properties. By using single-factor experiments, we examined the dependence of ceramic performance on Shoushan stone content. Its influence on glaze microstructure, copper ion valence states, and chromatic parameters was analyzed using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) techniques. The incorporation of 10 wt.% Shoushan stone significantly enhanced glaze density and gloss and stabilized the presence of Cu²⁺ ions, improving the purity and stability of the blue coloration. Physicochemical testing confirmed that the glaze layer exhibits high thermal shock resistance, mechanical strength, and environmental safety. These findings demonstrate that, along with solid waste valorization, rational reuse of Shoushan stone waste improves the structural and optical performance of copper-based blue glazes, underscoring their promising potential for sustainable ceramic applications.

This study examines the temperature-dependent compressive strength of refractory lining materials used in ferrosilicon casting ladles, with a focus on ShKU-grade chamotte bricks. The thermographic analysis of the ladle outer surface, along with the inspection of the inner lining, revealed that crack formation is primarily driven by thermal stress resulting from significant temperature gradients during non-steady-state thermal processes. The visual inspection of refractory samples confirmed the role of thermal stress in lining degradation. Compressive strength was measured for the fresh and spent refractories across a range of temperatures. Results show that strength increased within a specific temperature interval, reaching values 44% higher for the fresh chamotte refractories and 56% higher for partially spent samples compared to the baseline strength at 20°C.

Two industrial process schemes were employed to produce KS-4V and KI grade glasses from synthetic amorphous silica (SAS) and natural quartz, respectively. A comparison of the optical characteristics of the resulting glasses in the ultraviolet (UV) spectral region showed that glasses melted from SAS exhibit higher transparency and greater transmittance within the 190 – 1000 nm wavelength range. The difference in light transmittance coefficients is attributed to both the specific features of the melting processes and the presence of trace elements in raw materials.

This study investigates the chemical and mineralogical composition of magnesia raw materials, with particular emphasis on serpentinites from Uzbekistan. Their suitability for refractory production was evaluated using magnesia–silicate and magnesia–iron ratios. The physico-mechanical properties of fired test specimens were examined at 1000°C and 1100°C. The findings confirm the feasibility of utilizing domestic serpentinites for the development of magnesia refractory materials.

This paper investigates the annealing of high-purity synthetic quartz glass at 250°C and an elevated pressure of 7 MPa in a molecular hydrogen atmosphere. The treatment increased transmittance at 190 nm by 2%. Absorption within the 238–254 nm range is attributed to electronic transitions of non-bridging oxygen hole centers (NBOHCs). These centers are passivated by atomic hydrogen, which forms stable Si–OH groups and consequently reduces absorption in the target spectral region. The formation of a characteristic absorption band at 4200–4100 cm^–1, corresponding to molecular hydrogen dissolved in the quartz glass network, was confirmed by Fourier-transform infrared (FTIR) spectroscopy.

This study examines PbZrO₃ ceramics synthesized from nanodispersed PbO and ZrO₂ powders with BaTiO₃ nanoparticles with sizes of 50, 200, and 400 nm. The incorporation of barium titanate (BaTiO₃) nanoparticles into lead zirconate (PbZrO₃) ceramics expanded the stability range of the ferroelectric (FE) phase, extending it down to room temperature. As BaTiO₃ content increased, the peak of dielectric permittivity shifted toward lower temperatures, while ε^′ values rose significantly, reaching a maximum at 10 wt.% BaTiO₃ before declining at higher concentrations.

This paper presents an experimental study on the effect of 1.06 μm laser radiation on reaction-sintered silicon carbide ceramics. The experiments were carried out over a power density range corresponding to rapid material evaporation. The study determined the threshold laser power density and identified the range of power densities associated with minimal energy consumption during the laser machining of reaction-sintered silicon carbide ceramics.

This study presents the synthesis of mullite–silica ceramics with enhanced electrophysical properties from natural kaolinite sourced from the Orenburg region. The work focuses on the influence of heat treatment and raw material dispersion on the phase formation process. The phase composition was characterized using differential thermal analysis (DTA), thermal process simulation during firing, and x-ray diffraction (XRD). The results indicate that an optimal temperature regime, combined with preliminary mechanical activation (grinding) and chemical activation with oxalic acid, stabilizes the mullite phase and reduces the maturing of residual silica. This process yields materials with low dielectric loss across a wide frequency range, along with high thermal stability and improved insulating properties. The obtained samples exceed the stipulated requirements of GOST 20419–83 for key parameters, including thermal conductivity and dielectric loss, thereby confirming their potential for use in electrical insulation and thermal barrier applications in the energy and engineering sectors.

This study demonstrates the functional advantages of a reaction-sintered diamond – silicon carbide (D–SiC) composite for armor applications over standard silicon carbide, boron carbide, and corundum-based materials. Experimentally, the armor properties of the reaction-sintered D–SiC composite were found to meet the Br4 protection class. The prototype armor panels consisted of ceramic plates (thicknesses of 6 – 10 mm) bonded to a flexible backing of ultra-high-molecular-weight polyethylene (thickness of 8 – 10 mm). Ballistic testing confirmed that the panels exhibited no penetrations.