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

 

ISSN 0131-9582 (Online)

VOL 95, No. 3 (2022)

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  • POLARIZATION CONTROLLED BIREFRINGENCE IN SODIUM ALUMINOBORATE GLASS

    • Pages: 3-8
    • Views: 209
    The formation of birefringent nanogratings by a femtosecond laser beam in the volume of sodium aluminoborate glasses is demonstrated. The dependences of the optical retardance of the nanogratings on the parameters of laser exposure and the chemical composition of the glass are determined. It was shown that an increase in the Al2O3 concentration at a constant [Na2O]/([B2O3 + Al2O3]) molar ratio does not affect the ranges of laser exposure parameter for nanogratings formation but leads to an increase in the retardance of the nanogratings.
  • CERAMICS IN THE Na2O–CaO–SO3 SYSTEM AS A PROMISING INORGANIC POROGEN

    • Pages: 9-18
    • Views: 221
    Ceramics with phase composition after firing in the range of 600 – 900 °C represented by anhydrous calcium sulfate CaSO4, and calcium sodium sulfates (Na0,8Ca0,1)2SO4 and Na6Ca(SO4)4 were obtained from a powder mixture of sodium sulfate Na2SO4 and calcium sulfate dihydrate CaSO4?2H2O, taken at a molar ratio CaSO4?2H2O/Na2SO4 = 1. The phase composition of the powder mixture after homogenization in a planetary mill in an acetone medium, in addition to the starting salts, also included hydrated sodium calcium sulfate Na4Ca(SO4)3?2H2O. When kept in water for 5 and 60 min the mass loss of ceramic sample fired at 700 °C was 15 and 75 % respectively. Ceramics in the Na2O–CaO–SO3 system in the form of granules or complex shapes obtained using 3D printing can be used as a removable (soluble or leachable) porogen and/or a prototype of a porous space with a given architecture when creating porous polymer or inorganic materials.
  • THE USE OF TECHNOGENIC METALLURGICAL RAW MATERIALS FOR THE PRODUCTION OF CERAMIC MATERIALS WITH AN ANORTHITE PHASE

    • Pages: 19-25
    • Views: 181
    Studies have been carried out on the topic of obtaining ceramic materials for construction purposes with an anorthite phase. Clay and blast-furnace gas cleaning sludge were used as raw materials. The chemical compositions of raw materials for their use in the production of ceramic products have been studied. The calcium- and iron-containing compounds included in the composition of the gas cleaning sludge contribute to a decrease in the temperature of the formation of solid solutions and the anorthite phase. It has been established that with the addition of sludge up to 80 wt.% into the composition of the ceramic mixture increases the likelihood of an anorthite phase formation. The physico-mechanical parameters of the obtained ceramic samples have been studied. It has been established that the amount of gas cleaning sludge in the composition of the charge is 10 – 40 wt.% allows to obtain products with compressive strength 18 % higher than the control sample. The improvement in physical and mechanical properties is associated with an increase in the amount of the formed anorthite phase, which is confirmed by the data of X-ray phase analysis.
  • SYNTACTIC FOAMS BASED ON HOLLOW CERAMIC MICROSPHERES AND POLYCARBOSILANE

    • Pages: 26-31
    • Views: 178
    Syntactic foams based on hollow ceramic microspheres and the ceramic-forming binder polycarbosilane, capable of transition to silicon carbide at elevated temperatures, are considered. The processes of heat treatment of compositions and the transition of polycarbosilane to silicon carbide are considered. The physicomechanical and thermophysical characteristics of syntactic foams are studied.
  • METHODS OF UNCREASING OF THE WAX MODEL SURFACE PRIMARY WETTABILITY DURING LOST-WAX CASTING

    • Pages: 32-37
    • Views: 212
    Lost-wax casting is one of the most advanced ways to obtain geometrically complex castings of high quality.
    One of the main factors influenced on the casting properties is the quality of the ceramic mold face layer. A uniform deposition of the ceramic slurry can be achieved by condition of the wax surface is well wetted by the suspension dispersion medium. Since the surface of the wax model is hydrophobic and the dispersion medium of ceramic suspension is water, an increase of wettability may be achieved not only by SAS-wetting agent adding in suspension composition but also by activating of the model surface by chemical or physical methods.
    The paper presents the results of the different ways of chemical activation influence on the wettability of the wax model surface.
  • PHYSICO-CHEMICAL PROPERTIES OF MINERAL FIBERS OBTAINED ON THE BASIS OF ANDESIBASALTS

    • Pages: 38-45
    • Views: 200
    The article presents the results of research on the development of prototypes for obtaining mineral fibers based on the andesibazalt–slag–dolomit composition and the results of testing their physicochemical properties. Tests of chemical resistance of optimal compositions in aggressive conditions showed that the chemical resistance of the fibers depends on the content of metal oxides in the glass and their ratios that take into account the mutual influence of SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, K2O. It has been established that the studied andesibasalt of the Karahtay field is a promising raw material component for obtaining mineral fibers.
  • TRIBOLOGICAL BEHAVIOR OF LIQUID PHASE SINTERED SiC CERAMICS UNDER DRY CONDITION

    • Pages: 46-48
    • Views: 160

    Silicon carbide (SiC) ceramics with aluminum oxide (Al2O3)/aluminum nitride (AlN) and yttrium(III) oxide (Y2O3) as sintering aids are hot-pressed. The microstructure and tribological behavior of the as-prepared SiC ceramics slide against tungsten carbide (WC, Co bonded) and Al2O3 under variable velocities, loads, and temperatures are studied. The results showed that by using Al2O3–Y2O3 as a sintering aid, a fully dense (98 %) SiC ceramic is obtained at 1950 °С and 13 MPa. The sample coupled with WC, the friction coefficient (CoF) of the SiC ceramic is observed low at the applied high load, velocity, and temperature. On the other hand, in the sample coupled with Al2O3, the CoFs of the SiC ceramics are found low at the applied high load, moderate velocity, and low temperature. Coupled with the two tribo-pairs, the wear rates (WRs) of the SiC ceramics are not sensitive to the change in load, while CoF and WR of SiC ceramic increase with velocity initially, and then decrease. At the 0.05 m/s and 1.0 m/s, the WRs of both tribo-pairs are as low as 10–5 mm3/(Nm).
    The reduction in CoFs and WRs is strongly related to the formation of tribo-layers.
    The full article will be published in the translated version of the journal Glass and Ceramics, 2022, V. 79, No. 3–4