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Kinetics of Crystallization of Stoichiometric SiO 2 Glass in H 2 O Atmospheres
Author(s) -
WAGSTAFF F. E.,
RICHARDS K. J.
Publication year - 1966
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.1151-2916.1966.tb15387.x
Subject(s) - crystallization , activation energy , impurity , water vapor , stoichiometry , adsorption , water of crystallization , oxygen , nitrogen , chemical engineering , materials science , kinetics , chemistry , inorganic chemistry , analytical chemistry (journal) , environmental chemistry , organic chemistry , physics , quantum mechanics , engineering
Crystallization rates were measured in vacuum, dry nitrogen, and water‐saturated nitrogen atmospheres from 1300° to 1540°C. In all cases the observed rates were linear. Three reactions appeared to contribute to crystallization: the intrinsic crystallization, the impurity effect of H 2 O vapor, and furnace contamination. Enhancement of crystallization by both water vapor and furnace contamination is attributed to the breaking of silicon—oxygen bonds of the glass structure. Competitive adsorption mechanisms were proposed to characterize the adsorption of water and impurity species. The activation energy for apparent intrinsic crystallization was 134 kcal/mole; the activation energy for crystallization in H 2 O vapor was 77 kcal/mole.