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Structure and viscosity of phase‐separated BaO–SiO 2 glasses
Author(s) -
Gueguen Yann,
Houizot Patrick,
Célarié Fabrice,
Chen Mingwei,
Hirata Akihiko,
Tan Yongwen,
Allix Mathieu,
Chenu Sébastien,
RouxLanglois Clément,
Rouxel Tanguy
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14642
Subject(s) - barium , materials science , raman spectroscopy , silicate , analytical chemistry (journal) , phase (matter) , viscosity , barium oxide , amorphous solid , quenching (fluorescence) , mineralogy , silicon , crystallography , chemistry , oxide , composite material , optics , metallurgy , fluorescence , physics , organic chemistry , chromatography
Barium silicate glasses with 0‐40 mol% BaO were synthesized either by aerodynamical levitation and laser heating (at low barium content) or by conventional melting and quenching process. Characterization by means of Raman scattering spectroscopy and scanning transmission electron microscopy reveals a structural transition between glasses with low BaO content (<10 mol%) showing an atomic network resembling the one of amorphous silica, and glasses with a BaO content larger than 10 mol%, which exhibit the typical signature of a binary silicate glass with Q 2 and Q 3 units. Viscosity curves show a marked increase of the viscosity as the BaO content decreases below 20 mol%. Barium is found to easily diffuse and promote phase separation while silicon remains homogeneously distributed. A dramatic increase in the viscosity is observed as phase separation proceeds, resulting in the formation of Ba‐rich nodules in a percolating SiO 2 ‐rich matrix at low barium content, or in Ba‐poor nodules in a BaO‐rich matrix at large barium content.