Univerzita Pardubice Fakulta chemicko- technologická

Univerzita Pardubice

Zaměstnanci
|
Studenti
English

Publikace detail

Sodium borophosphate glasses modified with niobium pentoxide

Autoři: Hostinský Tomáš | Mošner Petr | Koudelka Ladislav

Rok: 2022

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Sodium borophosphate glasses modified with niobium pentoxide	In this contribution borophosphate glasses of the series (100-x)[0.4Na2O-0.2Nb2O5-0.4P2O5]-xB2O3 were studied in a composition range of x = 0-48 mol% B2O3. Basic physical properties were determined, and thermal properties studied by differential thermal analysis, thermomechanical analysis, and hot-stage microscopy. The glass structure was investigated using Raman spectroscopy and 11B and 31P MAS NMR. The electrical properties of the glasses were obtained by using impedance spectroscopy. Glass transition temperature increases in range of 0-16 mol% B2O3, further additions of B2O3 results in a decrease of Tg. All glasses except samples x = 8, 16 crystallize in the temperature range 650-700 ° C. The glass refractive index values follow the trend of Tg. From 11B MAS NMR spectra development is visible that the relative number of BO4 boron species with tetragonal coordination decreases with increasing B2O3 content, while the number of trigonal BO3 species increases. 31P MAS NMR spectra of studied glasses contain one major resonance which shifts upfield with increasing content of B2O3. This shift is due to the increasing connectedness of the glass network, which is based on the decrease in the number of Na+ cations. Raman spectra are mainly dominated by the vibration of the Nb-O bond in the NbO6 octahedra. The intensity of this vibration decreases with decreasing Nb2O5 content. With the addition of B2O3, a decrease in DC conductivity is observed, which is attributed to the decrease in the concentration of Na+ ions.