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Strengthening of Glass Surfaces by Sulfur Trioxide Treatment
Author(s) -
MOCHEL ELLEN L.,
NORDBERG MARTIN E.,
ELMER THOMAS H.
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.tb13173.x
Subject(s) - soda lime glass , sulfur , soda lime , oxide , sulfur trioxide , materials science , layer (electronics) , oxygen , chemistry , chemical engineering , mineralogy , inorganic chemistry , composite material , metallurgy , sulfur dioxide , organic chemistry , engineering
Removal of soda from a glass surface at high temperature can, on cooling, give appreciable strengthening due to lowering of the expansion coefficient at the surface. Soda depletion has been accomplished previously by treating a high‐expansion soda‐lime glass with SO 2 in the presence of oxygen and water. The depletion rate can be doubled by using dispersed platinum to catalyze the oxidation of SO 2 to SO 3 before the gas reacts with soda from the glass. The data are consistent with the soda depletion being Fickian both with and without the catalyst. Alumina in the glass composition markedly increases the strength which can be attained by sulfur oxide treatment. Although the percentage of soda retained in the leached layer increases, the total amount of soda removed from the glass also increases as alumina increases. It must follow that the depth of the layer is increased.