Sodium tracer diffusion and 11B NMR study of glasses of the type (Na2O)0.17(B2O3)x(SiO2)0.83−x

Autor:	Xinwei Wu, Rüdiger Dieckmann, Randall E. Youngman
Rok vydání:	2013
Předmět:	Borosilicate glass Diffusion Sodium Enthalpy Analytical chemistry chemistry.chemical_element Nuclear magnetic resonance spectroscopy Condensed Matter Physics Electronic Optical and Magnetic Materials chemistry TRACER Materials Chemistry Ceramics and Composites Boron Order of magnitude
Zdroj:	Journal of Non-Crystalline Solids. 378:168-176
ISSN:	0022-3093
DOI:	10.1016/j.jnoncrysol.2013.06.012
Popis:	Sodium tracer diffusion coefficients, D Na ⁎ , have been measured for sodium borosilicate glasses of the type (Na 2 O) 0.17 (B 2 O 3 ) x (SiO 2 ) 0.83−x as a function of temperature and the composition parameter x. At constant temperature, the tracer diffusion coefficient of sodium decreases as x increases. The activation enthalpy derived from sodium tracer diffusion data for temperatures up to about 308 °C increases with increasing values of x from about 60 to 85 kJ/mol. The pre-exponential factor of the sodium tracer diffusion coefficient as a function of x varies by about one order of magnitude. Results of 11 B NMR measurements performed to study variations of the structure of the investigated glasses with their composition indicate that the fraction of boron present in BO 4 tetrahedra decreases with increasing values of x and also that the Si/B-ratio next to BO 4 tetrahedra is always significantly larger than the overall Si/B-ratio in the glass.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::cf3bbc6d4f3ecf3f6dd3a2c1380c9c37 https://doi.org/10.1016/j.jnoncrysol.2013.06.012 Zobrazit plný text záznamu Full Text from ScienceDirect