Glass Physics and Chemistry最新文献

Crystal glass is characterized by a high transmittance, high refractive index, good hardness, and chemical stability, which makes it an excellent material for use in a wide variety of decoration, lamp, handicrafts, high-grade tableware, and jewelry. Nevertheless, these applications of crystal glass involve complicated mechanical processing, including cutting and polishing. This article examines the morphology, optical, mechanical, and chemical properties of crystal glass following a range of processing treatments. The findings revealed that the surface roughness of the crystal glass subjected to mechanical processing was markedly diminished, while the optical transmittance was enhanced. However, the hardness of the polished sample exhibited a notable decline. Concurrently, the quantity of lead ion precipitation following acid immersion increased considerably, reaching 2.63 mg/L. After acid treatment, many hydrogen ions appeared on the surface, and the water contact angle of the sample significantly increased, especially for untreated crystal glass samples with more surface area.

Factors influencing the density of nanoparticles include the intrinsic density of the element or compound that forms the nanoparticle, surface properties, pore structure, and agglomeration within suspensions or aggregates. In this case, the first factor is the main one; therefore, the methods for quickly assessing changes in nanoparticle density as a function of particle size, which we considered in this paper, are relevant. An estimate of the actual density of a substance is proposed depending on the number of atoms in a particle (nanoparticle). It is found that density oscillations are observed in the dependence of the nanoparticle density on its radius. Calculations are carried out for C (diamond, graphite, graphene), Fe, Si, and ZrO₂. When density is considered as a function of the number of atoms, oscillations are observed, which vanish at a content of 10⁴ atoms, after which the density approaches values similar to those of bulk materials. The values of the radius of metal microparticles correspond to the values obtained earlier by other authors when explaining the deviation of the specific heat capacity of nanoparticles from the macroscopic heat capacity, based on solutions of the Schrödinger equation. The threshold values of mass and radius are unique for each substance and are significantly smaller than the Planck mass.

Mechanochemical treatment of air-dried mixtures composed of polyvinyl alcohol (or polyacrylamide) and food-grade gelatin at various mass ratios is carried out in a vibrating cup sample grinder for 1, 3, and 5 min. As a result, gelatin/polyvinyl alcohol and gelatin/polyacrylamide composites are obtained. The structure, morphology, and optical and rheological properties are studied using infrared spectroscopy, scanning electron and optical microscopy, gravimetry, viscometry, and turbidity spectroscopy. It is found that mechanical activation promotes noncovalent interactions between components and the formation of a new system of hydrogen bonds, leading to changes in the microstructure of powders and in the viscosity of aqueous solutions. It is shown that mechanochemical activation of gelatin with polyacrylamide and polyvinyl alcohol is a promising method for producing film composites with a wide range of applications, including the pharmaceutical and medical fields.

Modern technologies for the creation of metal matrix composites (MMCs) are based on the directional nanostructuring (reinforcement) of a metal matrix with ceramic nanostructures leading to reinforced materials with improved mechanical characteristics. MMCs’ development firstly requires to establish chemical and physical parameters that control the properties of solids of varying degrees of complexity and materials based on them. Experimental and theoretical studies of nanostructuring processes help to synthesize nanomaterials with controlled mechanical properties. In this work, composites where titanium carbide (TiC) nanostructures with a size of 1–2 nm are evenly distributed in the bulk Ni matrix were obtained using surface chemical reactions (SCRs). Surface reactions provide the absence of interphase boundaries.

The collaborative preparation of slag glass–ceramics using iron tailings and fly ash is an important approach to achieving high-value recycling of solid waste. In this study, a method of microwave-assisted heat treatment for preparing slag glass–ceramics was introduced to enhance crystallization efficiency and reduce energy consumption. The relationship between the microstructure and properties of glass–ceramics under the non-thermal effect of microwaves was investigated using traditional XRD, Raman, SEM, and other analytical techniques, and the structural evolution rule of the microcrystalline phase was obtained through in situ tracking tests. The migration and diffusion mechanism of CaF₂ and Fe₂O₃ under the catalytic effect of the microwave electromagnetic field was innovatively studied. The results show that microwave treatments improved crystallization efficiencies, enabling the augite to crystallize uniformly in the glass. Due to the interaction of microwave energy with the absorbing medium in glass ceramics, Ca²⁺ and F⁻ ions preferentially migrate and aggregate, resulting in the “micro-focusing effect” and a decrease in crystallization activation energy. In addition, the microwave electric field accelerated the diffusion of Fe ions, targeted and regulated the silica glass network to polymerize and form the augite.

Aluminum-doped zinc oxide (AZO) thin films were fabricated at room temperature on glass substrates using confocal RF magnetron sputtering, with a deposition time of 60 min. To assess the effects of thermal treatment, the films were subsequently annealed in a vacuum for 60 min at temperatures of 250 and 450°C. An investigation was carried out to study the films’ physical structure, surface morphology, and optoelectrical characteristics using advanced characterization techniques. The annealing process significantly enhanced the crystalline quality by improving c-axis orientation, increasing crystallite size, and reducing compressive stress. The surface morphology and roughness examined using atomic force microscopy (AFM) and Field emission scanning electron microscopy (FESEM), exhibited noticeable changes with varying annealing temperatures, highlighting a clear dependence on the thermal treatment. Optical properties, measured via UV–Visible spectroscopy, showed that the as-deposited films had an average transmittance of 68.7% in the visible spectrum. After annealing, both optical transmittance and band gap values increased substantially, with higher annealing temperatures further improving the films’ transparency and optical performance. Hall-effect measurements indicated that the electrical properties of the films improved with increasing annealing temperature. Notably, the AZO thin film annealed at 450°C exhibited a lower resistivity of 4.3 × 10^–4 Ω cm and an average optical transmission of 87.5%, along with a high figure of merit (φ_TC) value of 1.1 × 10^–3 Ω^–1. These results highlight the vital role of vacuum annealing in optimizing AZO thin films for optoelectronic applications.

The dependence of the linear attenuation coefficients (LACs) of X-ray and gamma radiation in the range of photon energies, E, from 0.2 to 3.0 MeV for optical lead-containing glasses of the flint group on their density when it changes from 2.50 to 6.79 g/cm³ is studied. The study is based both on the published data on the LAC of such glasses, and the LAC values of an additional 37 grades obtained in this study using data on the composition of the glasses and their density, as well as the mass attenuation coefficients (MACs) of the oxides included in the glass composition. It is shown that for radiation with photon energies of 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.5, 2.0, and 3.0 MeV, the LAC values of lead-containing glasses of the flint group fit well onto straight lines depending on their density, whose slope decreases with increasing E. At the same time, glasses such as crown flints (CF), flints (F), heavy flints (HF), and super-heavy flints (SHF) form one subgroup, whereas special flints (SF) form another, whose LAC values for each value of photon energy are slightly lower than those of glasses of the first subgroup at approximately the same density values. Equations are derived that describe these straight lines, allowing the LAC of new lead-containing flint glass to be accurately calculated based on their density. For some grades of glass, at energies E from 0.2 to approximately 0.5 MeV, the LAC values are located slightly above or below these lines. These deviations from straight lines are explained by the differences in the nomenclature and concentrations of “heavy” oxides with their higher MAC values (PbO, Ta₂O₅, Gd₂O₃, La₂O₃, BaO, Sb₂O₃, CdO, Nb₂O₅, and ZrO₂) in these glasses and in glasses of other grades with similar density, whose LAC values fit well onto straight lines. At energies E from approximately 0.5 to 3.0 MeV, no deviations of the LAC values of these glasses from straight lines are observed.

New ceramic materials that have ionic conductivity and can be used as components in various electrochemical devices are being actively developed. This study focuses on the electrical conductivity of a recently prepared layered perovskite-like oxide of La₂BaLu₂O₇, which has a two-layer Ruddlesden–Popper structure. Compounds with this structure exhibit ionic conductivity, whose level depends on the substitutions in the crystal lattice. It is found that the electrical conductivity in La₂BaLu₂O₇ has a mixed oxygen-ionic character, with ionic conductivity accounting for an average of 66.5% of the total conductivity.

Tailings, as industrial waste, have always been unable to be utilized due to the presence of impurities. If the disc granulation technology can be used to process tailings into ceramic products that meet production requirements and can replace coarse aggregate in terms of performance indicators, it will not only solve the problem of huge consumption of coarse aggregate resources, but also solve the problem of recycling tailings as industrial waste. During the granulation process, there are omni-directional integrative (ODI) constraints between the tailings particles, forming a suspended liquid bridge, which consolidates the constraints to form a shape. This article studies the process of adjusting disc granulation and the ratio of raw materials to obtain high-performance ceramic particles, and improves the strength of ceramic particles through secondary processing.

The patterns of formation of geopolymer materials based on aluminosilicates of the kaolinite subgroup (Al₂Si₂O₅(OH)₄·nH₂O) with different particle morphologies using natural platy kaolinite and nanotubular halloysite as an example under conditions of their alkaline activation are studied. It is found that the compressive strength of halloysite-based samples can be 1.4 times higher than the strength of kaolinite-based samples and reach 85 MPa. X-ray diffraction and electron microscopy studies show differences in the phase composition and morphology of the resulting samples depending on the nature of the initial precursor. Nanotube halloysite-based samples geopolymerize over a wide range of SiO₂/Al₂O₃ ratios, which leads to enhanced mechanical strength. Platy kaolinite can recrystallize under alkaline activation conditions into zeolites with A and Y structures, which, accordingly, reduces the mechanical strength of the samples.