Steklo i Keramika (Glass and Ceramics). Monthly scientific, technical and industrial journal

 

ISSN 0131-9582 (Online)

VOL 95, No. 5 (2022)

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  • FEATURES OF CRYSTALLIZATION OF LITHIUM-ALUMINOSILICATE GLASS MICROSPHERES OBTAINED IN A HIGH-TEMPERATURE PLASMA FLOW

    • Pages: 3-9
    • Views: 197
    The influence of the spheroidization process in the flow of high-temperature plasma of glass based on the Li2O–Al2O3–SiO2 (LAS) system doped with 1.0 mol. % Nd2O3 on its crystallization properties is investigated. The resulting microspheres with a size of 32 – 64 ?m are characterized by a significantly higher glass transition temperature Tg compared to the Tg of the initial glass (751 °C and 677 °C, respectively), which may be due to both a change in chemical composition during spheroidization and a fundamentally different thermal history of microspheres and glass. Despite the delayed crystallization kinetics, the glass-ceramic structure based on ?-eucryptite-like solid solutions of LixAlxSi1 – xO2 is formed in microspheres, as in the initial glass, under the action of heat treatment, indicating the possibility of both obtaining microspheres with the glass-ceramic structure and varying their coefficient of thermal expansion near zero values.
  • IMPROVING THE QUALITY OF SAFE TEMPERED GLASS IN THE PRODUCTION PROCESS

    • Pages: 10-14
    • Views: 161
    Selective control of the tempered glasses produced was carried out. Deviations of bent products from a given shape are revealed. Linear adaptive models describing the dependence of the shape of products and the results of mechanical strength tests on the quenching mode are compiled. Simulation modeling of the quenching process control algorithm shows the possibility of improving the quality of safe tempered glasses produced.
  • SOME FEATURES OF THE TECHNOLOGY FOR PROCESSING CONTAINER GLASS CULLET

    • Pages: 15-21
    • Views: 934
    Some features of the technology for processing container glass cullet were considered. The differentiated optical separation diagrams of colorless, brown and green cullet mixture was presentedduced.
  • THE INFLUENCE OF MAGNETITE ON THE RADIO-ABSORBING PROPERTIES OF POROUS GLASS COMPOSITE IN THE HIGH-FREQUENCY REGION

    • Pages: 22-30
    • Views: 143
    The effect of the addition of magnetite in the form of pyrite stubs on the physico-mechanical and radio-absorbing properties of the synthesized glass composite by the method of “cold” foaming is considered. Replacing glass powder with magnetite in the initial liquid-glass composition reduces the foaming coefficient from 80 to 20 %, which is due to a decrease in the viscosity of the composition due to the particle size of the additive (160 ?m), their high density (5100 kg/m3) and porous structure. It has been established that the optimal content of magnetite for obtaining a material with radio-absorbing properties is no more than 10 %. A porous glass composite with an average pore size of 2, containing 10 % magnetite, has an absorption coefficient of electromagnetic radiation in the high-frequency range (120 – 250 GHz) on average 10 % more than a composite without an additive.
  • THERMOELECTRIC PROPERTIES OF CERMET Bi2Te3–Gd COMPOSITE

    • Pages: 31-37
    • Views: 173
    The aim of this paper is exploring an opportunity to improve the thermoelectric properties of the cermet Bi2Te3 + 0.5 at. % Gd composite. It was found that under spark plasma sintering, a composite microstructure consisting of the Ni inclusions, which are randomly distributed inside the grained Bi2Te3 matrix, is really formed. With introducing Ni inclusions in Bi2Te3, the specific electrical resistivity increases, and the total thermal conductivity decreases. The highest thermoelectric figure-of-merit for the composite (~ 0.63) happened to be slightly enhanced as compared to that for the matrix material (~ 0.58).
  • SINTERING PROCESSES AND SOLID-PHASE REACTIONS IN THE TRIPLE COMPOSITION “QUARTZITE–CLAY–ADDITIVES”

    • Pages: 38-44
    • Views: 185
    The article presents the results of a physicochemical study of the process of high-temperature sintering and solid-phase reactions in a ternary composition based on Koitash quartzite, Angren clay and Karakhtaisky limestone for obtaining unshaped dinas refractory materials. It was found that as a result of these processes, chemical interaction occurs both with the help of solid-phase reactions and with the participation of a liquid phase with the formation of highly basic aluminosilicate minerals with high refractoriness, strength and low porosity, which are reflected in the production of unshaped refractory materials with improved physical and mechanical technological properties.
  • LUMINESCENT SILICA AEROGEL DOPED BY COORDINATION SUBSTANCE OF BORON WITH 8-HYDROXYQUIONOLINE

    • Pages: 45-52
    • Views: 167
    A new luminescent hybrid material based on silica aerogel and a boron-containing coordination compound with 8-hydroxyquinoline has been created, and its physico-chemical and spectral-luminescent characteristics have been studied. A scheme for the synthesis of a hybrid luminescent material has been developed/ The scheme eliminates the need for preliminary expensive synthesis of a high-purity organoelemental boron-containing phosphor. It has been established that aerogel hydrophobization significantly increases the stability of the luminescent characteristics of the hybrid material.
  • PRODUCTION AND CHARACTERIZATION OF ZrO2–Al2O3–K2O BASED CERAMIC WHITENING AGENTS

    • Pages: 53-55
    • Views: 994

    Zircon-containing whitening agents are indispensable components increasing the cost of ceramic tiles. In the ceramic industry, the developing of unique and low-cost whitening agents with comparable final product quality is an essential motivation. In this study, a unique ZrO2–Al2O3–K2O-based whitening agent was developed by mixing zircon silicate, Al2O3, K-feldspar, and marble with various weight concentrations to reduce costs and give a valid alternative to the commercially available R6-coded ZrO2–Al2O3–Na2O whitening agent. To test the innovative ZrO2–Al2O3–K2O-based whitening agent’s efficiency, a systematic characterization procedure was utilized to reveal factors affecting the tile opacity, including size, shape, and distribution of opacifier particles and the incident light wavelength. First, X-ray diffraction and X-ray fluorescence analyses examined the initial grain sizes and structural properties of the whitening agent constituents. Second, a wet milling process in industrial mills was utilized to produce a homogenized ZrO2–Al2O3–K2O-based composite whitening agent. Structural, mineralogical, and morphological properties of the final product were determined after the drying process. The efficiency of the wet milling process was proved according to scanning microscopy analysis revealing homogenous particle size distribution of constituents with mainly composed of ZrO2, Al2O3, and SiO2 phases. Energy dispersive X-ray analysis reveals that Si–Al–O–Zr and Ca were major elements whereas Na was obtained as minor element.
    The full article will be published in the translated version of the journal Glass and Ceramics, 2022, V. 79, No. 5–6.