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Structure of Borosilicate and Borogermanate Melts at 1300°C; a Viscosity and Density Study
Author(s) -
RIEBLING E. F.
Publication year - 1964
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/j.1151-2916.1964.tb13794.x
Subject(s) - borosilicate glass , mole fraction , viscosity , boron , viscometer , mole , silicon , analytical chemistry (journal) , mineralogy , materials science , crystallography , chemistry , metallurgy , organic chemistry , composite material
An improved counterbalanced sphere viscometer‐densitometer was used to obtain information at temperatures between 1000° and 1400°C for (a) molten B 2 O 3 , (b) a series of borosilicate melts containing up to 55 mole % SiO 2 , and (c) a series of borogermanate melts containing up to 65 mole % GeO 2 . The dependence on composition of these structure‐sensitive parameters was used to develop a model for the alteration of molten B 2 O 8 by other network‐forming species. The B/Si or B/Ge ratio is shown to be a significant factor in determining melt structure. The silicon (or germanium) atoms appear to be widely separated in the B 2 O 2 solvent for compositions in the 0 to 10‐20 mole % SiO 2 (or GeO 2 ) region. The evidence suggests that a gradual microclustering of SiO 2 (or GeO 2 ) accompanies moderate departures from ideality for B 2 O 3 in the 10‐20 to 60 mole % SiO 2 (or GeO 2 ) region. Extensive micro‐clustering of SiO 2 (or GeO 2 ), approaching network formation, appears to occur in the 60 to 100 mole % SiO 2 (or GeO 2 ) region; some of the boron atoms remain in clusters and/or are forced to adopt a tetrahedral configuration in this region.