Chemically durable phosphate opal glasses
AssigneeCorning Glass Works
InventorsJames E. Flannery, John L. Stempin, Dale R. Wexell
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Abstract
This invention relates to the manufacture of spontaneous opal glasses demonstrating a dense, milky-white appearance, excellent resistance to attack by water and detergents, softening points in excess of 760.degree. C., and containing either NaBaPO.sub.4 or Na.sub.5 P.sub.3 O.sub.10 as the predominant crystal phase. The glasses consist essentially, expressed in weight percent on the oxide basis, of 6-12% Na.sub.2 O, 5-16% BaO, 0.9-7% Al.sub.2 O.sub.3, 2-7% B.sub.2 O.sub.3, 55-70% SiO.sub.2, and 5-9% P.sub.2 O.sub.5.
Claims2
A fluorine-free spontaneous opal glass demonstrating a dense, milky-white appearance, excellent resistance to attack by water and alkaline media, a softening point greater than 760.degree. C., and containing either NaBaPO.sub.4 or Na.sub.5 P.sub.3 O.sub.10 as the predominant crystal phase consisting essentially, expressed in terms of weight percent on the oxide basis, of 6-12% Na.sub.2 O, 5-16% BaO, 0.9-7% Al.sub.2 O.sub.3, 2-7% B.sub.2 O.sub.3, 55-70% SiO.sub.2, and 5-9% P.sub.2 O.sub.5.
Dependencies are inferred from the claim text.