Chemically prestressable aluminosilicate glass and products made therefrom

• US 5,895,768 A
• Filed: 04/25/1997
• Issued: 04/20/1999
• Est. Priority Date: 04/26/1996
• Status: Expired due to Term

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott Glaswerke
• Inventors: Speit, Burkhard
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US08/837,867
• Time in Patent Office: 725 Days
• Field of Search: 501/57, 501/64, 501/69, 428/694 ST
• US Class Current: 428/846.9
• CPC Class Codes: C03C 1/004 Refining agents refining C03B5/225
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/095 containing rare earths
• CPC Class Codes: C03C 3/112 containing fluorine

Abstract

The chemically prestressable glass having a low bubble count and bubble size has the following composition in mol %, based on a total amount of oxides present, SiO₂ from 63.0 to 67.5 mol %, Al₂ O₃ from 9.5 to 12.0 mol %, Na₂ O from 8.5 to 15.5 mol %, K₂ O from 2.5 to 4.0 mol %, MgO from 3.0 to 9.0 mol %, sum of CaO+SrO+BaO+ZnO from 0 to 2.5 mol %, TiO₂ from 0.5 to 1.5 mol %, CeO₂ from 0.02 to 0.5 mol %, As₂ O₃ from 0.02 to 0.35 mol %, SnO₂ from 0. to 1.0 mol %, and F₂ from 0.05 to 2.6 mol %, wherein the molar ratio SiO₂ !/ Al₂ O₃ ! is 5.3 to 6.85, the molar ratio Na₂ O!/ K₂ O! is 3.0 to 5.6, the molar ratio Al₂ O₃ !/ K₂ O! is 2.8 to 3.6 and the molar ratio Al₂ O₃ !/ TiO₂ +CeO₂ ! is 7.6 to 18.5, but, when arsenic-free, SnO₂ is from 0.02 to 1.0 mol % and F₂ is from greater than 0.5 to 2.6 mol %. The invention also includes a safety glass and a hard disk for information storage made from this chemically prestressable glass.

Claims

1. A chemically prestressable glass having a low bubble count and bubble size having the following composition in mol %, based on a total amount of oxides present:

space="preserve" listing-type="tabular">______________________________________SiO.sub.2 from 63.0 to 67.5 mol %,Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %,Na.sub.2 O from 8.5 to 15.5 mol %,K.sub.2 O from 2.5 to 4.0 mol %,MgO from 3.0 to 9.0 mol %,Σ

CaO+SrO+BaO+ZnO from 0 to 2.5 mol %,TiO.sub.2 from 0.5 to 1.5 mol %,CeO.sub.2 from 0.02 to 0.5 mol %,As.sub.2 O.sub.3 from 0.02 to 0.35 mol %,SnO.sub.2 from 0 to 1.0 mol %, andF.sub.2 from 0.05 to 2.6 mol %,______________________________________

wherein a molar ratio of the SiO₂ to the Al₂ O₃ is between 5.3 and 6.85, a molar ratio of the Na₂ O to the K₂ O is between 3.0 and 5.6, a molar ratio of the Al₂ O₃ to K₂ O is between 2.8 and 3.6 and a molar ratio of the Al₂ O₃ to a total amount of the TiO₂ and the CeO₂ is between 7.6 and 18.5.

2. The chemically prestressable aluminosilicate glass as defined in claim 1, containing from 0.05 to 0.7 mol % of F₂.

3. The chemically prestressable aluminosilicate glass as defined in claim 1, containing from 0.1 to 2.5 mol % of a sum total amount of said CaO, and SrO, and BaO and said ZnO.

6. A hard disk for information storage made from the chemically prestressable aluminosilicate glass as defined in claim 1.

7. A prestressed safety glass made from the chemically prestressable aluminosilicate glass as defined in claim 1.

4. The chemically prestressable glass having a low bubble count and bubble size which can be produced on float glass equipment and having the following composition in mol %, based on a total amount of oxides present:

space="preserve" listing-type="tabular">______________________________________SiO.sub.2 from 63.0 to 67.5 mol %,Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %,Na.sub.2 O from 8.5 to 15.5 mol %,K.sub.2 O from 2.5 to 4.0 mol %,MgO from 3.0 to 9.0 mol %,Σ

CaO+SrO+BaO+ZnO from 0 to 2.5 mol %,TiO.sub.2 from 0.5 to 1.5 mol %,CeO.sub.2 from 0.02 to 0.5 mol %,SnO.sub.2 from 0.02 to 1.0 mol %, andF.sub.2 from greater than 0.5 to 2.6 mol %,______________________________________

wherein a molar ratio of the SiO₂ to the Al₂ O₃ is between 5.3 and 6.85, a molar ratio of the Na₂ O to the K₂ O is between 3.0 and 5.6, a molar ratio of the Al₂ O₃ to K₂ O is between 2.8 and 3.6 and a molar ratio of the Al₂ O₃ to a total amount of the TiO₂ and the CeO₂ is between 7.6 and 18.5.

5. The chemically prestressable aluminosilicate glass as defined in claim 4, containing from 0.1 to 2.5 mol % of a sum total amount of said CaO, and SrO, said BaO and said ZnO.

8. A prestressed safety glass made from the chemically prestressable aluminosilicate glass as defined in claim 4.