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Structure and properties of ZnO-B2O3-P2O5-GeO2 glasses.
Autoři: Mošner Petr | Vosejpková Kateřina | Koudelka Ladislav
Rok: 2008
Druh publikace: ostatní - přednáška nebo poster
Název zdroje: 6th International conference on inorganic materials - Delegate manual
Název nakladatele: Elsevier
Místo vydání: Kidlington
Strana od-do: P2-12
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Struktura a vlastnosti skel systému ZnO-B2O3-P2O5-GeO2. Práce se zabývá studiem vlivu obsahu GeO2 na strukturu a vlastnosti skel systému ZnO-B2O3-P2O5-GeO2 připravených v kompoziční řadě (100-x)[50ZnO-10B2O3-50P2O5]-xGeO2, kde x=0-50mol% GeO2.
eng Structure and properties of ZnO-B2O3-P2O5-GeO2 glasses. This work deals with the study of the effect of GeO2 on the structure and properties of zinc borophosphate glasses. Zinc-germanium borophosphate glasses were prepared in compositional series (100-x)[50ZnO-10B2O3-40P2O5]-xGeO2 with x = 0-50 mol% GeO2 by slow cooling of the melt or by quenching between two copper blocks (for x = 45 and 50 mol% GeO2) from the temperature region of 1200-1300oC. These glasses were characterized by the measurements of density, molar volume and chemical durability. Thermal properties were investigated by DTA and TMA methods. Their structure was studied by Raman spectroscopy. The incorporation of germanate structural units into the parent borophosphate glass results in a decrease of their molar volume and chemical durability while their density and glass transition temperature increase. Thermal expansion coefficient obtained by TMA measurements decreases slightly from 8.4 to 6.5 ppm/°C with increasing GeO2 content. The observed changes in the glass transition temperature and thermal expansion coefficient show on increasing bonding forces in the glass structure. DTA measurements showed that all prepared glasses crystallize under heating in the temperature range of 630-700°C and that their thermal stability increases with increasing amount of GeO2. Major compounds formed by glass crystallization were Zn2P2O7 and BPO4, but any crystalline phase containing germanium was not revealed. Raman spectroscopy revealed structural changes in the glasses and the relations between structural changes and changes in the glass properties are discussed. The incorporation of germanate structural units is reflected in the Raman spectra of the studied glasses by the presence of vibrational modes associated with Ge-O-Ge bonds. borophosphate glasses, germanium oxide, structure, properties.