Glasses and glass-ceramics - USPatent 3935019
Glasse Parent Case Text
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of copending application Ser. No. 349,152 filed Apr. 9, 1973 now abandoned; which in turn is a division of copending application Ser. No. 241,448 filed Apr. 5, 1972 now U.S. Pat. No. 3,852,077, the entire disclosures of both copending applications are relied on herein.
Glasse Parent Claims
I claim:
1. A thermally crystallizable glass suitable for crystallization to a glass-ceramic having good dielectric properties and an index of refraction in said glass-ceramic in excess of 2.000 and higher than the index of refraction of said glass, said glass consisting essentially of the following composition:
wherein the molar ratio of Nb.sub.2 O.sub.5 to PbO ranges from about 0.9:1 to about 1.5:1.
2. A glass-ceramic body having good dielectric properties including a dielectric constant in excess of 50 (Room temperature 0.5 MHz) and a dissipation factor of less than 2%, said glass-ceramic body being formed by thermal in situ crystallization of a glass body consisting essentially of the following composition:
wherein said RO is SrO or BaO and the molar ratio of said Nb.sub.2 O.sub.5 to said RO is from about 1:3 to about 2:1.
3. A glass-ceramic body having good dielectric properties including a dielectric constant in excess of 50 (Room temperature 0.5 MHz) and a dissipation factor of less than 2%, said glass-ceramic body being formed by thermal in situ crystallization of a glass body consisting essentially of the following composition:
wherein the molar ratio of Nb.sub.2 O.sub.5 to PbO ranges from about 0.9:1 to about 1.5:1.
4. A transparent glass-ceramic body having an index of refraction in excess of 2.000, said glass-ceramic body being formed by thermal in situ crystallization of a glass body having a lower index of refraction and consisting essentially of the following composition:
wherein said RO is SrO or BaO and the molar ratio of said Nb.sub.2 O.sub.5 to said RO is from about 1:3 to about 2:1.
5. A transparent glass-ceramic body having an index of refraction in excess of 2.000, said glass-ceramic body being formed by thermal in situ crystallization of a glass body having a lower index of refraction and consisting essentially of the following composition:
wherein the molar ratio of Nb.sub.2 O.sub.5 to PbO ranges from about 0.9:1 to about 1.5:1.