Materials Science Forum Vol. 1179

Abstract: In this study, binary ZnSe:Fe²⁺ crystals and a concentration series of ternary Zn_1-xMg_xSe:Fe²⁺ (0 < x < 0.6) were grown using the vertical Bridgman method in graphite crucibles under high argon pressure. The influence of Mg incorporation on the structural perfection, electronic energy levels, and optical absorption/emission characteristics was systematically investigated. With increasing Mg content, a monotonic redshift of both absorption and luminescence bands was observed, which is attributed to modifications in the crystal field surrounding Fe²⁺ ions and to changes in the host lattice parameters. The correlation between composition, crystal structure, and optical response was analyzed to elucidate the mechanisms of Fe²⁺-related transitions. These results demonstrate the potential of Zn_1-xMg_xSe:Fe²⁺ as tunable mid-infrared laser media and provide guidelines for the compositional engineering of A²B⁶-based laser materials.

Abstract: The impact of silver nanoparticles (AgNPs) on the intestine and reproductive system have not been sufficiently studied. Meanwhile, the relationship between disruption of the intestinal epithelial barrier and female reproductive disorders is under active investigation.The aim of the work was to evaluate the effects of AgNPs on small intestine cells and oocytes follicular environment cells under conditions of experimental premature ovarian failure (ePOF) and the use of Resveratrol in female mice.Methods. ePOF was modeled by immunizing with a suspension of kidney antigen (10 μl per 10 g of weight) according to the scheme. AgNPs (2,0 mg/kg) and Resveratrol (RES, 50,0 mg/kg) was administered intraperitoneally once a day three times after the last immunization.Enterocytes were isolated and cell death was assessed by the method of two-color fluorescent nucleic acid dye. Analyzed data with GraphPad Prism.Results. It was found that AgNPs under ePOF conditions did not cause significant changes in the viability of ileal enterocytes. In cells of the follicular environment of oocytes, under the influence of nanoparticles, a 1.40-fold decrease in the proportion of living cells and an increase in the proportion of cells with morphological signs of apoptosis and necrosis were observed, by 1.17 times and 1.43 times, respectively (p<0.05, n=6).Under ePOF conditions, the use of RES after AgNPs caused a 1.15-fold increase in the proportion of live cells in the ileum and a 1.43-fold decrease in apoptotic cells. In the follicular environment of oocytes, the proportion of live cells increased 1.54 times, and the proportion of cells with morphological signs of apoptosis and necrosis decreased 1.28 and 1.62 times, respectively (p<0.05, n=6).Conclusions. New data on the impact of AgNPs on small intestinal cells and the oocytes follicular environment cells have been obtained, encouraging further research possible therapeutic treatment of such nanoparticles.

Abstract: Polycrystalline C₆₀ saturated with molecular hydrogen and nitrogen were studied using the spectral-luminescent method of registration in the quantum counting mode at a low temperature of 20 K. Previously, it was found that the temperature limit of the adsorption crossover (the transition from the diffusion mechanism of intercalation - physisorption to chemical interaction - chemisorption) for fullerite C₆₀ in an H₂ atmosphere is about 250 °C [1], and in an N₂ atmosphere – 420 °C [2], respectively. At saturation temperatures above those indicated, the process of chemical interaction of impurity molecules and the fullerite matrix occurs with the formation of new compounds. Therefore, saturation was carried out at temperatures of 300 °C for hydrogen and 450 °C for nitrogen under a pressure of 30 atm. For the first time, the results of registration of photoluminescent radiation at low temperatures from new substances based on fullerite C₆₀ are presented. A mixture of weakly saturated fulleranes C₆₀H_X was obtained by saturation of hydrogen from the gas phase at a temperature close to the sorption crossover temperature, and their low-temperature photoluminescence was identified for the first time. The analysis of the "blue" shift of the beginning of the spectrum of such radiation allowed us to more accurately attribute the obtained material to the initial segment of the fullerane series. The presence of radiation of the azafullerene dimer (biazafullerene) (C₅₉N)₂ in the spectra of the reaction products of C₆₀ with N₂ was also detected. It was shown that for polycrystalline samples of C₆₀ saturated in a nitrogen atmosphere, the characteristic luminescence of biazafullerene with a maximum at 1.53 eV determines the intensity and shape of the entire short-wave part of the emission spectrum of the complex of synthesized substances.

Abstract: Thermoelectric generators (TEGs) are vital, reliable energy sources for both extreme environments such as deep space exploration and off-grid terrestrial applications, as well as emerging fields like wearable energy harvesters and biocompatible medical sensors. This study focuses on tin selenide (SnSe) combined with ductile silver sulfide (Ag₂S) to leverage their complementary properties: SnSe’s promising thermoelectric performance and mechanical robustness for homojunction TEGs, and Ag₂S’s exceptional ductility and thermal sensitivity ideal for flexible, biocompatible devices. Materials were synthesized using scalable powder metallurgy and spark plasma sintering (SPS) techniques, ensuring reproducibility and microstructural control tailored for these diverse applications. Our Bi-doped polycrystalline SnSe exhibits a unique polarity switching phenomenon and anisotropic behavior influenced by dopants (Bi, Ag, In), enabling optimized thermoelectric and mechanical properties that reduce interfacial stresses and enhance durability in harsh conditions. Meanwhile, the Ag₂S materials combine thermoelectric efficiency with fast thermal response and flexibility, suited for continuous physiological monitoring in wearable systems. The hybrid integration of SnSe homojunctions with flexible Ag₂S devices opens new possibilities for durable, efficient thermoelectric energy harvesting across wide temperature gradients in aerospace and biomedical fields.

Abstract: This paper presents a method for fabricating a porous Ni-Al₂O₃-Al compact using uniaxial double-action pressing, which was subsequently infiltrated with molten aluminium. Al₂O₃ ceramic particles primarily serve to create porosity within the composite compact. Due to the difficulty pressing hard metal powders, aluminium powder was introduced into the Ni+Al₂O₃ mixture to act as a plasticizer, improving the material's compressibility. Experiments indicated that the optimal infiltration temperature was 750 °C with an infiltration duration of 300 seconds. To evaluate the reaction extent among the initial components, a subset of infiltrated samples underwent annealing at 800 °C for 3 hours under an inert argon atmosphere. Both annealed and reference samples were subjected to thermal cycling. The microstructure and thermal stability of the resulting composite materials were analyzed and characterized using scanning electron microscopy with energy-dispersive spectroscopy, respectively.

Abstract: Alumina (Al₂O₃) is a technical ceramic widely selected for demanding applications due to its excellent material properties, such as high strength, corrosion resistance, and thermal stability. In this study, the effect of the sintering temperature of 3D-printed alumina to its surface characteristics and its subsequent performance as a copper-metallized ceramic substrate was investigated. Green parts of alumina samples were prepared using stereolithography (SLA) 3D printing, debound, then sintered at temperatures ranging from 1660°C to 1740°C. Surface roughness was quantified using Atomic Force Microscopy (AFM), while the copper layer's adhesion was assessed via tape and burnishing tests. Electrical conductivity was measured with a four-point probe. A non-monotonic relationship between sintering temperature and surface roughness was observed. Roughness (Ra​) decreased as temperature increased from 1660°C to 1720°C, attributed to enhanced densification. However, increasing the temperature to 1740°C led to grain coarsening and a slight increase in roughness due to excessive grain growth. Stronger copper adhesion was achieved on smoother surfaces produced at optimized sintering temperatures. Electrical conductivity was also determined with a minimum sheet resistance of 0.089 mΩ/sq achieved.

Abstract: In this study, high-hardness transparent silicon nitride was fabricated using liquid-phase sintering. Powders were prepared by adding sintering additives in various ratios, followed by dry pressing at 200 MPa to obtain a circular green body. After forming the green body in the previous process, low-pressure liquid-phase sintering was performed at 1900 °C and 0.7 MPa under a nitrogen atmosphere to produce transparent silicon nitride. According to the test results, the material exhibited a density of 3.148 g/cm³, a Vickers hardness (HV10) of 2100, and a transmittance of 38.5% at a wavelength of 750 nm.

Abstract: This paper demonstrates the potential use of affordable, and efficient electrocatalysts, which can maintain the efficiency and stability of platinum-group metals in water-splitting. The study focuses on the optimization and setup of a PEM electrolyzer, alongside the development of new methods for preparing membrane electrode assemblies (MEA) using cost-effective and efficient catalyst materials. The integration of a fibrous membrane layer into the MEA architecture represents a promising design strategy, offering excellent structural and transport properties. Herein, a simple preparation method for modified NiCoP electrocatalysts in the form of carbon fibers is presented, using needleless electrospinning combined with airbrush spraying of an Ir-black solution onto a perfluorosulfonic membrane (Nafion), later pressed together with NiCoP carbon fibers to form a custom-made MEA. For electrochemical testing, custom made MEA was directly evaluated in the PEM electrolyzer setup, providing a preliminary demonstration of overall performance and stability.

Abstract: This work demonstrates the successful preparation of two types of photocatalytically active nanostructured materials from an industrial waste product – Sal Ammonia Skimming – using hydrochloric acid as a leaching medium. The whole production process was developed to prepare valuable ZnO nanomaterials in both fibrous and powdered forms. This involved a sequence of hydrometallurgical processing, needle-less electrospinning, and conventional calcination of recycled environmentally polluting industrial waste. The morphologies and phase composition of the resulting ZnO powder and ZnO fibers were analyzed using SEM, EDS, and XRD analyses. The impact of the morphology of the prepared nanomaterials on the photocatalytic efficiency of the ZnO-based photocatalyst – powder versus ZnO nanofibers – was evaluated through decolorization experiments of the commonly used methylene blue dye in batch mode. Methylene blue was chosen as a model substance for toxic industrial pollutants. A 25 W UVA lamp with an emission maximum at 365 nm was used as a light source. Removal efficiencies were carefully tested and compared for different nanomaterial morphologies and preparation conditions. The most photocatalytically active ZnO-based nanomaterial was the electrospun nanofibrous one calcined at 600 °C for 1 h. This material achieved 100 % removal of a 10⁻⁵ mol/L methylene blue dye from the solution within 700 minutes at an increased catalyst-to-dye ratio of 500 mg/50 ml. Based on the obtained results, it can be stated that the prepared materials exhibit high photocatalytic activity under UV light irradiation and have a potential for photocatalytic water remediation applications.