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

 

ISSN 0131-9582 (Online)

VOL 95, No. 2 (2022)

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  • POLARIZATION CONTROLLED BIREFRINGENCE IN LITHIUM ALUMINOSILI-CATE GLASS

    • Pages: 03-07
    • Views: 207

    The rise of polarization-controlled birefringence under a series of femtosecond laser pulses in the bulk of lithium silicate and lithium aluminosilicate glasstentatively attributed to the formation of nanogratings is demonstrated. The dependences of the retardance of the light passing through the modified regions on the parameter of laser radiation and the chemical composition of the glass are determined. It is shown that an increase of Al2O3 content at the expense of alkali content in glass composition leads to an increase in the minimum number of pulses for the formation of a birefrin-gent region, as well as an increase in the retardance.

  • INVESTIGATION OF THE INTERACTION OF LEAD-SILICATE GLASSES WITH BARIUM HYDROXIDE

    • Pages: 08-11
    • Views: 183

    The effect of alkaline treatment on the destruction process and some surface characteristics of mechanically processed glass discs of lead-silicate glasses C87-2 and C78-4 has been studied.
    It is shown that the interaction of these glasses with barium hydroxide leads to the removal of silicic acid from the gel
    surface, which in turn improves the water wettability and optical transparency of the glasses. It is proposed in the production technology of electric vacuum devices, where lead-silicate glasses are used, to use washing with barite water for rapid coagulation of silica gel, which eliminates the appearance of foreign particles on the surface of the glasses.

  • CERAMIC TILE BASED ON LOCAL HYDROMICA CLAY AND PEGMATITE DUST REMOVAL WASTE

    Autors:

    Ilyina V. P.

    • Pages: 12-19
    • Views: 169

    The goal of the present contribution is to study the possible use of local clay of hydromica type for facing tile production. Pegmatite dust removal waste from the Chupa Milling and Dressing Factory was added as flux to the clay. Mineralogical, chemical and grain-size analyses of the clay and waste were performed. The mineral composition of the waste and clay were analyzed using the laboratory equipment of the Analytical Centre at the Institute of Geology, Karelian Research
    Centre, RAS. Experimental samples of ceramic tile were produced and the physico-mechanical properties of the products were assessed. The ceramics produced can be used for facing walls and furnaces. Local clay of hydromica type and pegmatite dust removal waste can be used to increase the mechanical bending strength and heat resistance of facing tiles, to decrease their thermal conductivity in comparison with samples containing clay, kaolin, feldspar and lime and to contribute to pegmatite waste utilization.

  • CERAMICS BASED ON FLUORINATED TALC

    • Pages: 20-26
    • Views: 231

    A dense-sintered protoenstatite ceramics based on fluorinated talc was obtained. Influence of BaO and Al2O3 additives on the sinterability, structure and strength of ceramics was investigated. It makes possible to reduce the sintering temperature to 1225 – 1250 °C due to formation of glassy phase. Additive of ZnO intensifies solid phase sintering at 1320 °C.
    It significantly improves compressive strength of ceramics up to 660 MPa that exceeds the strength of traditional steatite materials by 3 times.

  • STUDY OF THE PASSAGE OF ELECTRONS WITH ENERGY OF 12 – 15 keV THROUGH GLASS TAPERED CAPILLARIES

    • Pages: 27-31
    • Views: 192

    This paper presents the results of experimental studies on the passage of an electron beam with an energy of 12 and 15 keV through glass tapered macrocapillaries. As a result of the measurement, the absence of an explicit dependence of the output current on the electron energy was shown. Time-dependent measurements of the beam current at the exit from the capillaries were carried out.

  • EFFECT OF CALCIUM ADDITION ON THE PROPERTIES AND MICROSTRUCTURE OF FLY ASH-BASED GEOPOLYMERS FOR APPLICATIONS IN SUSTAINABLE CONSTRUCTIONE

    • Pages: 32-39
    • Views: 219

    The article describes a study of the physical and mechanical properties and microstructure of geopolymer materials for construction based on low-calcium fly ash from CHP-22, depending on the type of activator, temperature and humidity conditions of curing and the introduction of an additional source of calcium (CaO) in the amount of 10, 15 and 20 wt. %.
    It was found that for the fly ash under study, the most promising type of activator is a sodium silicate solution with a silicate modulus SiO2 / Na2O = 1; the preferred curing mode is steam treatment at 90 °C. With the introduction of 15 % CaO into the geopolymer mixture, it was possible to increase the compressive strength by more than 2.5 times (to 38 МПа), the open porosity decreased from 24 to 7 %, and the water absorption from 15 to 3 %. However, a further increase in the CaO content leads to degradation of properties due to a significant reduction in the setting time of the raw mixture.

  • SYNTHESIS OF Bi2NiTa2O9 WITH A PYROCHLORE-TYPE STRUCTURE

    • Pages: 40-46
    • Views: 226

    Nickel pyrochlore of the composition Bi2NiTa2O9 was synthesized by the solid-phase reaction method (sp. gr. Fd-3m, a = 10.5238 ?). The process of phase formation of nickel-containing bismuth tantalate Bi2NiTa2O9 with a pyrochlore structure is investigated. The pyrochlore phase synthesis reaction is described by the interaction of orthorhombic bismuth orthotantalate and nickel oxide. Synthesis proceeds mainly at temperatures above 900 °С. The duration of calcination of the preparations leads to the coalescence of grains with the formation of larger particles.
    The calcination temperature did not significantly affect the microstructure of the samples. The samples are characterized by a porous dendritic microstructure with a grain size of 0.5 – 1.0 µm. The optimal conditions for obtaining pure pyrochlore can be considered a temperature of 1050 °С and calcination time of 15 hours.

  • THE NUCLEATION EFFECT OF PbSe ADDITIVE ON Bi2Sr2CaCu2Oδ GLASS CERAMICS

    • Pages: 47-48
    • Views: 212

    The crystallisation kinetics and effects of doping on Bi2Sr2CaCu2Oδ (BSCCO) glass ceramic system with 0.0, 0.1, 0.3 and 0.5 % PbSe were investigated in this study. Using differential thermal analysis (DTA), the effects of PbSe doping on glass transition, nucleation and crystallisation temperature of glass were investigated.
    The DTA results were analysed using the Ozawa, Augis–Bennett, Takhor and Kissinger equations for nucleation kinetics to uncover the activation energies and Avrami parameters. Thermogravimetric analysis revealed that the amount of oxidation in the structure increased with increasing PbSe-doping concentration.