Browsing by Author "Karadashka I."

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    Glass Formation and Properties of Multicomponent Glasses of the As2Se3-Ag2Te-GeTe System
    (2024-01-01) Karadashka I.; Ivanova V.; Jordanov V.; Karadjova V.
    Chalcogenide alloys of As2Se3-Ag2Te-GeTe were synthesized using the melt-quenching technique. By the visual and XRD analyses, the state of obtaining alloys was proven (glass, crystalline, glass + crystalline), and the glass formation region in the system was established. The thermal characteristics of some samples were determined—temperatures of glass transition (Tg); crystallization (Tcr); and melting (Tm). The basic physicochemical parameters, such as density (d) and Vickers microhardness (HV), were measured. Compactness (C), as well as some thermomechanical characteristics, such as module of elasticity (E), volume (Vh), and formation energy (Eh) of micro-voids, were calculated, and the influence of the composition on these characteristics was investigated. The addition of silver telluride resulted in a decrease in Tg and HV values and an increase in d and Vh values. No thermochemical effects of crystallization or melting were detected in some of the alloys. The obtained results were in agreement with the available literature data for similar systems.
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    New chalcogenide glasses in the Ag2Te-As2Se3-CdTe system
    (2008-07-01) Vassilev V.; Karadashka I.; Parvanov S.
    Chalcogenide glasses from the Ag2Te-As2Se3-CdTe system were synthesized. The basic physicochemical parameters such as density (d), microhardness (HV) and the temperatures of phase transformations (the glass transition Tg, crystallization Tcr and melting Tm) were measured. Compactness and some thermomechanical characteristics such as volume (Vh) and formation energy (Eh) of micro-voids in the glassy network, as well as the module of elasticity E were calculated. The overall mean bond energy 〈E〉, the mean coordination number Z, the mean bond energy of the average cross-linking/atom and the average bond energy per atom of the ``remaining matrix``-over(E, -)c and over(E, -)rm, as well as the average heteropolar bond energy Ehb, the degree of ``cross-linking/atom`` Pp and the radial bond strength were determined. The correlation between the composition and properties of the Ag2Te-As2Se3-CdTe glasses was established and comprehensively discussed. © 2008 Elsevier Ltd. All rights reserved.
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    PREPARATION AND PROPERTIES OF BULK AMORPHOUS CHALCOGENIDES OF THE A2Se3 - GeTe - CdTe SYSTEM
    (2022-01-01) Karadashka I.; Aljihmani L.; Jordanov V.
    Bulk amorphous chalcogenides from the As2Se3 - GeTe - CdTe system were studied. The alloys were prepared using the method of multi-step direct mono-temperature synthesis and characterized with the help of visual analysis and X-ray powder diffraction (XRD). The region of glass formation was outlined. Some physicochemical properties of the samples as microhardness, density, and characteristic temperatures, were determined. Compactness (C), modulus of elasticity (E), minimal volume of micro-voids (Vh), and energy of their formation (Eh) were calculated. The composition dependence of these parameters was discussed.