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

 

ISSN 0131-9582 (Online)

VOL 95, No. 6 (2022)

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  • SUBSTRATES FOR THE SURFACE ENHANCED RAMAN SPECTROSCOPY BASED ON NANOPOROUS GLASS ACTIVATED WITH SILVER PARTICLES

    • Pages: 3-10
    • Views: 155
    Substrates for the surface enhance Raman spectroscopy (SERS) are being actively developed with the aim of precise detecting of the low concentrations of organic molecules. However, the complexity and cost of substrates manufacturing often limits their applications. In this work, we proposed a simple method for preparing SERS substrates based on the nanoporous glass functionalized with silver particles and demonstrated their efficiency in the detecting of low concentrations of benzoic acid.
  • EFFECT OF THE SYNTHESIS METHOD ON THE PHYSICOCHEMICAL PROPERTIES AND PHASE COMPOSITION OF ZIRCONIA

    • Pages: 11-22
    • Views: 163
    Hydrated zirconia was obtained by solid state synthesis and precipitation. Physicochemical properties and phase composition of calcined hydrated zirconia was investigated by XRD, IR and DSC-TG. Hydrated zirconia obtained by solid state synthesis has lower moisture content and higher filterability to compare with precipitated one. Zirconia precursor synthesis with ammonium carbonate considerable decrease specific surface area to compare with precursor precipitated by ammonium hydroxide or ammonia. Tetragonal and monoclinic zirconia was obtained by hydrated zirconia calcination under 450 °C. Calcination temperature increase up to 600 °C lead to drastically decrease of tetragonal zirconia content. The roast obtained under 1150 °C contain only monoclinic zirconia.
  • INVESTIGATION OF THE POSSIBILITY OF REDUCING ENERGY COSTS DURING LASER SCRIBING OF GLASS AND CERAMIC PLATES

    Autors: A. F. Kovalenko
    • Pages: 23-28
    • Views: 148
    In the framework of the one-dimensional problem of evaporation of the absorbing layer of the material with the “instantaneous” release of laser pulse energy, the possibility of reducing energy costs when scribing glass and ceramic plates is investigated. A method of scribing is proposed, in which the laser radiation released through the back surface of the plate is returned to the plate using a mirror with a reflection coefficient of ~ 99 %. Optimal modes of plate scribing have been determined. It is shown that with deep scribing, it is possible to reduce energy costs by 1.4 – 1.8 times compared to traditional laser scribing. When the depth of the scribing groove is less than 0.3 of the plate thickness, the use of the considered method is impractical due to the insignificance of the positive effect.
  • THE RESULTS OF THE STUDY ON THE CYCLIC STRENGTH OF THE DEVELOPED CUTTING CERAMICS

    • Pages: 29-33
    • Views: 154
    The paper presents the results of a study on the cyclic strength of cutting ceramics: a replaceable polyhedral plate developed at NSTU and VOK-60 cutting ceramics when processing a hardened steel billet made of HVG steel (45 HRC) with two opposite grooves. Turning was performed until the cutting edge of the plates was destroyed. Using the HITACHI S3400N electron microscope, the structure of the destroyed surface layer was investigated and the mechanism of destruction of the cutting edge of tool plates made of cutting ceramics was determined. It has been established that the developed cutting ceramics have a greater resistance to fracture under conditions of intermittent turning of hardened steel compared to the VOK-60 brand. The low operability of the cutting plates made of the developed ceramics under conditions of intermittent turning is mainly caused by the chipping of the cutting edge due to the formation of microcracks at the grain boundaries. A characteristic feature of the mechanism of brittle fracture of cutting ceramics is intergrain tearing and chipping of large Al2O3 grains.
  • ASPECTS OF OBTAINING HOMOGENEOUS DENSE CERAMICS FROM NON-SCARCE RAW MATERIALS

    • Pages: 34-38
    • Views: 144
    The combined effect of the microwave field and the content of reinforcing medium-dispersed silicon carbide particles on the density of a ceramic material based on montmorillonite containing clay of the Orenburg region is investigated.
    It is shown that with the content of carbide particles in the range of 20 – 30 wt. % after microwave drying of the samples, the maximum values of the density of the “ceramic mass-silicon carbide” system are reached. The increase in the density of all ceramic mass compositions is due to an increase in sintering coefficients and the appearance of a strong stable sillimanite phase in the phase compositions.
  • INFLUENCE OF LIQUID FOAMING AGENT DISTRIBUTION ON THE FORMATION OF FOAM GLASS POROUS STRUCTURE

    • Pages: 39-44
    • Views: 128
    It was shown that the use of liquid-phase foaming agents is promising for the synthesis of foam glass. The dynamics of the change in the glass particles size in the process of batch obtaining was studied. It was shown that additional grinding of glass powder particles occurs during the mixing process. The influence of the time of the batch mixing on the structure of the foam glass was investigated. It was shown that the density of the obtained foam glass is directly proportional to the batch mixing duration. Changes in the structure of the material associated with the processes of distribution of a liquid foaming mixture on glass powder particles during mixing and subsequent changes in the dynamics of the glycerol thermal destruction processes were described.
  • ASSOCIATED SYNTHESIS OF MICROGRANULAR FOAM-GLASS CERAMICS FROM DIATOMACEOUS CLAYS

    Autors: K. S. Ivanov
    • Pages: 45-50
    • Views: 133
    The technology of synthesis of porous microgranular material based on diatomaceous clay is considered. The process of foaming microgranules in an industrial furnace was implemented in the way of obtaining granular foam-glass ceramic of coarse fractions. The main properties of microgranular foam-glass ceramic samples were investigated depending on the NaOH content in the charge, as a result of which its composition was optimized to obtain particles with a size of 75 ?m and a minimum content of particles sinking in water. The peculiarity of the porous structure of microgranular foam-glass ceramic makes it possible to obtain more durable lightweight grouting slurries in comparison with the traditional additive. The research results expand the range of materials made of foam-glass ceramic and the raw material base due to the more accessible for development deposits of diatomaceous clays in the arctic regions.
  • HIGH CAPABILITY OF THE BUFFERING AGENT IN PROVIDING CONSTANT pH TO IMPROVE THE BEHAVIOUR OF SYNTHESIZED HA/b-TCP CERAMIC

    • Pages: 51-52
    • Views: 113
    During the synthesis of different calcium phosphate phases, the pH variation of the slurry solution affects the purity, structure, and chemical composition of final products. High-capacity buffering agent solutions were used to keep the pH value constant during the synthesis procedure. Consequently, high purity and single-phase HA, b-TCP. Also, morphological evaluation of granules from plate-like to completely porous structure is another result of keeping the slurry pH constant during the synthesis step. Increasing the specific surface area of BCP granules from 10 to 38 m2/g affected the in vitro behaviour of the products. Precipitation of 20 nm hydroxyapatite phase after suspension of experimental samples for 30 days in simulation body fluid attributed to using Tris buffer solution during synthesis.