ION EXCHANGABLE GLASS WITH DEEP COMPRESSIVE LAYER AND HIGH DAMAGE THRESHOLD

• US 20120135226A1
• Filed: 11/28/2011
• Published: 05/31/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bookbinder, Dana Craig, Gross, Timothy Michael, Potuzak, Marcel
• Granted Patent: US 9,346,703 B2
• Time in Patent Office: Days
• US Class Current: 428/335
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/062 with less than 40% silica by weight
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: Y10T 428/264 Up to 3 mils

Abstract

Glasses comprising SiO₂, Al₂O₃, and P₂O₅ that are capable of chemical strengthened by ion exchange and having high damage resistance. These phosphate-containing glasses have a structure in which silica (SiO₂) is replaced by aluminum phosphate (AlPO₄) and/or boron phosphate (BPO₄).

Claims

1. A glass comprising SiO₂, Al₂O₃, P₂O₅, and at least one alkali metal oxide (R₂O), wherein 0.75≦

[(P₂O₅(mol %)+R₂O(mol %))/M₂O₃ (mol %)]≦

1.3, where M₂O₃=Al₂O₃+B₂O₃.

2. The glass of claim 1, wherein the glass is ion exchanged, and wherein the glass has a Vickers crack initiation threshold of at least about 20 kgf.

3. The glass of claim 1, wherein the glass is ion exchanged to a depth of layer of at least about 40 μ

m from a surface of the glass.

4. The glass of claim 3, wherein the glass is ion exchanged to a depth of layer extending at least about 60 μ

m from a surface of the glass.

5. The glass of claim 1, wherein the glass is ion exchanged, and wherein the glass fails at a load of greater than about 80 kgf when subjected to abraded ring-on-ring loading.

6. The glass of claim 1, wherein the glass has an anneal point of at least about 600°

C.

7. The glass of claim 1, wherein the glass comprises:

about 40 to about 70 mol % SiO₂;

0 to about 28 mol % B₂O₃;

about 0 to about 28 mol % Al₂O₃;

about 1 to about 14 mol % P₂O₅; and

about 12 to about 16 mol % R₂O.

8. The glass of claim 7, wherein the glass comprises:

about 40 to about 64 mol % SiO₂;

0 to about 8 mol % B₂O₃;

about 16 to about 28 mol % Al₂O₃;

about 2 to about 12% P₂O₅; and

about 12 to about 16 mol % R₂O.

9. The glass of claim 7, wherein the glass further comprises at least one alkaline metal oxide.

10. The glass of claim 1, wherein aluminum is present in the glass in the form of tetrahedral aluminum oxide units and phosphorus is present in the glass in the form of tetrahedral phosphorus oxide units.

11. The glass of claim 10, wherein the tetrahedral aluminum oxide and tetrahedral phosphorus oxide units replace tetrahedral silica units in the glass.

12. The glass of claim 1, wherein boron is present in the glass in the form of tetrahedral boron oxide units and phosphorus is present in the form of tetrahedral phosphorus oxide units.

13. The glass of claim 12, wherein the tetrahedral boron oxide and tetrahedral phosphorus oxide units replace tetrahedral silica units in the glass.

14. The glass of claim 1, wherein the glass is substantially free of non-bridging oxygen atoms.

15. The glass of claim 1, wherein [(P₂O₅(mol %)+R₂O(mol %))/M₂O₃ (mol %)]=1.

16. The glass of claim 1, wherein M₂O₃=Al₂O₃.

17. The glass of claim 1, wherein the molar volume of the glass is at least about 29 cm³/mol.

18. The glass of claim 1, wherein the glass has a depth of layer extending to at least about 30 μ

m from a surface of the glass when ion exchanged in an ion exchange bath comprising KNO₃ at 410°

C. for 2 hours.

19. A glass comprising SiO₂, Al₂O₃, P₂O₅, and at least one alkali metal oxide (R₂O), wherein 0.75≦

[(P₂O₅(mol %)+R₂O(mol %))/M₂O₃ (mol %)]≦

1.3, where M₂O₃=Al₂O₃+B₂O₃, wherein the glass, when ion exchanged, has a Vickers crack initiation threshold of at least about 10 kgf.

20. The glass of claim 19, wherein the glass is ion exchanged to a depth of layer extending at least about 40 μ

m from a surface of the glass.

21. The glass of claim 20, wherein the glass is ion exchanged to a depth of layer extending at least about 60 μ

m from a surface of the glass.

22. The glass of claim 19, wherein the glass is ion exchanged, and wherein the glass fails at a load of greater than about 80 kgf when subjected to abraded ring-on-ring loading.

23. The glass of claim 19, wherein the glass has an anneal point of at least about 600°

C.

24. The glass of claim 19, wherein the glass comprises:

about 40 to about 70 mol % SiO₂;

0 to about 28 mol % B₂O₃;

about 0 to about 28 mol % Al₂O₃;

about 1 to about 14 mol % P₂O₅; and

about 12 to about 16 mol % R₂O.

25. The glass of claim 24, wherein the glass comprises:

about 40 to about 64 mol % SiO₂;

0 to about 8 mol % B₂O₃;

about 16 to about 28 mol % Al₂O₃;

about 2 to about 12% P₂O₅; and

about 12 to about 16 mol % R₂O.

26. The glass of claim 24, further comprising at least one alkaline metal oxide.

27. The glass of claim 19, wherein aluminum is present in the glass in the form of tetrahedral aluminum oxide units and phosphorous is present in the glass in the form of tetrahedral phosphorous oxide units.

28. The glass of claim 19, wherein the tetrahedral aluminum oxide and tetrahedral phosphorous oxide units replace tetrahedral silica units in the glass.

29. The glass of claim 19, wherein boron is present in the glass in the form of tetrahedral boron oxide units and phosphorous is present in the glass in the form of tetrahedral phosphorous oxide units.

30. The glass of claim 29, wherein the tetrahedral boron oxide and tetrahedral phosphorous oxide units replace tetrahedral silica units in the glass.

31. The glass of claim 19, wherein the glass is substantially free of non-bridging oxygens.

32. The glass of claim 19, wherein [(P₂O₅(mol %)+R₂O(mol %))/M₂O₃ (mol %)]=1.

33. The glass of claim 19, wherein M₂O₃=Al₂O₃.

34. The glass of claim 19, wherein the glass has a depth of layer extending to at least about 30 μ

m from a surface of the glass when ion exchanged in an ion exchange bath comprising KNO₃ at 410°

C. for 2 hours.