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US 2024/0199474 A1Published application
Transparent glass ceramic, especially as a cover pane
AssigneeSchott AG
InventorsMeike Schneider, Bernd Rüdinger, Uwe Martens
Life of this patent
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Abstract
A transparent, chemically prestressable or chemically prestressed glass ceramic is provided. The glass ceramic has keatite as a main crystal phase, a transmittance greater than 80% at a thickness of 0.7 mm, a haze of less than or equal to 10, and a crystal phase content of at least 80% by weight of keatite solid solution based on all crystal phases in the glass ceramic.
Claims20
A transparent, chemically prestressable or chemically prestressed glass ceramic, comprising:
- keatite as a main crystal phase;
- a transmittance greater than 80% at a thickness of 0.7 mm;
- a haze of less than or equal to 10;
- and
- a crystal phase content of at least 80% by weight of keatite solid solution based on all crystal phases in the glass ceramic.
2 more elements
A method for producing a prestressed glass ceramic, comprising:
- producing a silicate green glass by a melting process and a hot shaping process;
- exposing the silicate green glass to a temperature treatment having at least one nucleation step carried out in a temperature range of 690° ° C. to 850° C. for a period of 5 min to 72 hour and at least one ceramization step carried out in a temperature range of 780° C. to 1100° C. for a period of 3 min to 150 hours;
- and
- performing at least one ion exchange in an exchange bath having a composition of 100% by weight to 0% by weight KNO3, 0% by weight to 100% by weight NaNO3, 0% by weight to 5% by weight LiNO3 at a temperature of the exchange bath between 370° C. and 500° C. and for a period of between 2 hours and 50 hours such that the prestressed glass ceramic has keatite as a main crystal phase, a transmittance greater than 80% at a thickness of 0.7 mm, a haze of less than or equal to 10, and a crystal phase content of at least 80% by weight of keatite solid solution based on all crystal phases in the glass ceramic.
1 more element
Dependencies are inferred from the claim text.