Glasses having improved toughness and scratch resistance

• US 8,969,226 B2
• Filed: 11/25/2008
• Issued: 03/03/2015
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Dejneka, Matthew John, Ellison, Adam James, Gomez, Sinue, Morena, Robert Michael
• Primary Examiner(s): Green, Anthony J
• Assistant Examiner(s): Bolden, Elizabeth A
• Application Number:
  US12/277,573
• Publication Number:
  US 20090142568A1
• Time in Patent Office: 2,289 Days
• Field of Search: 501 66- 70, 501/72, 428/410, 428/426
• US Class Current: 501/66
• CPC Class Codes: C03C 21/00 Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• CPC Class Codes: C03C 2204/00 Glasses, glazes or enamels with special properties
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 4/18 for ion-sensitive glass
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A silicate glass that is tough and scratch resistant. The toughness is increased by minimizing the number of non-bridging oxygen atoms in the glass. In one embodiment, the silicate glass is an aluminoborosilicate glass in which −15 mol %≦(R₂O+R′O—Al₂O₃—ZrO₂)—B₂O₃≦4 mol %, where R is one of Li, Na, K, Rb, and Cs, and R′ is one of Mg, Ca, Sr, and Ba.

Claims

1. A silicate glass, the silicate glass being ion exchangeable and comprising:

a. 9.39-18 mol % alumina, 6-20 mol % Na₂O,and up to 9.01 mol % boron oxide; and

b. at least one alkaline earth metal oxide, wherein −

15 mol %≦

(R₂O+R′

O—

Al₂O₃ —

ZrO₂)—

B₂O₃ ≦

2 mol%, where R is Na and optionally one or more of Li, K, Rb, and Cs, and R′

is one or more of Mg, Ca, Sr, and Ba.

2. The silicate glass according to claim 1, wherein the silicate glass has a toughness in a range from about 0.7 MPa m^0.5 up to about 1.2 MPa m^0.5.

3. The silicate glass according to claim 2, wherein the silicate glass has a brittleness of less than about 8.5 μ

<sup>−

0.5</sup>.

4. The silicate glass according to claim 1, wherein the silicate glass is ion exchanged and has a surface compressive stress of at least about 200 MPa and a surface compressive layer, the surface compressive layer having a depth of at least about 30 μ

m.

5. The silicate glass according to claim 1, wherein the silicate glass is ion exchanged, and wherein the at least one alkali metal oxide in the silicate glass is ion exchanged with at least one of sodium ions, silver ions, potassium ions, cesium ions, and rubidium ions.

6. The silicate glass according to claim 1, wherein the silicate glass has a liquidus viscosity of at least 100 kpoise.

7. The silicate glass according to claim 6, wherein the silicate glass is substantially free of lithium.

8. The silicate glass according to claim 7, wherein the silicate glass is down-drawable.

9. The silicate glass according to claim 8, wherein the silicate glass is slot drawn or fusion drawn.

10. The silicate glass according to claim 1, wherein the silicate glass forms a cover plate for a mobile electronic device.

11. The silicate glass according to claim 10, wherein the cover plate has a thickness in a range from about 0.3 mm up to about 1.5 mm.

12. The silicate glass according to claim 1, wherein the silicate glass is substantially free of at least one of antimony oxide and arsenic oxide.

13. The silicate glass according to claim 1, wherein the silicate glass comprises 62-70 mol. % SiO₂;

up to 9.01 mol % B₂O₃;

0-15 mol % Li₂O;

0-18 mol % K₂O;

less than 3 mol % MgO;

less than 3 mol % CaO; and

0-5 mol % ZrO₂.

14. The silicate glass according to claim 13, wherein the silicate glass comprises:

64-66 mol % SiO₂;

9.39-12 mol % Al₂O₃;

1-9.01 mol % B₂O_3;

0-5 mol % Li₂O;

6-12 mol % Na₂O;

1-4 mol % K₂O;

less than 3 mol % MgO;

less than 3 mol % CaO; and

0-2 mol % ZrO₂.

15. The silicate glass according to claim 14, wherein 20 mol % ≦

R₂O+R′

≦

24 mol %.

16. The silicate glass according to claim 14, wherein 16 mol % ≦

Al₂O₃+B₂O₃+ZrO₂ ≦

29 mol %.

17. An aluminoborosilicate glass, the aluminoborosilicate glass being ion exchangeable and having a toughness in a range from about 0.7 MPa m^0.5 up to about 1.2 MPa m^0.5 and brittleness of less than about 8.5 μ

<sup>μ

m−

0.5</sup>, wherein the aluminoborosilicate glass comprises;

9.39-18 mol % alumina, 6-20 mol % Na₂O, and up to 9.01 mol % boron oxide;

at least one alkaline earth metal oxide R′

O, where R′

is or more of Mg, Ca, Sr, and Ba; and

at least one alkali metal oxide R₂O, where R is Na and optionally one or more of Li, K, Rb, and Cs, and wherein −

15 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃ ≦

2 mol %.

18. The aluminoborosilicate glass according to claim 17, wherein the aluminoborosilicate glass comprises:

64-66 mol % SiO₂;

9.39-12 mol % Al₂O₃;

1-9.01 mol % B₂O₃;

0-5 mol % Li₂O;

6-12 mol % Na₂O;

1-4 mol % K₂O;

less than 3 mol % MgO;

less than 3 mol % CaO; and

0-2 mol % ZrO₂.

19. The aluminoborosilicate glass according to claim 18, wherein 20 mol %≦

R₂O+R′

O≦

24 mol %.

20. The aluminoborosilicate glass according to claim 18, wherein 16 mol %≦

Al₂O₃+B₂O₃+ZrO₂ ≦

29 mol %.

21. The silicate glass according to claim 17, wherein the silicate glass is ion exchanged and has a surface compressive stress of at least about 200 MPa and a surface compressive layer, the surface compressive layer having a depth of at least about 30 μ

m.

22. The silicate glass according to claim 17, wherein the silicate glass is substantially free of lithium.

23. The silicate glass according to claim 17, wherein the silicate glass is down-drawable.

24. The silicate glass according to claim 17, wherein the silicate glass forms a cover plate for a mobile electronic device, wherein the cover plate has a thickness in a range from about 0.3 mm up to about 1.5 mm.

25. The silicate glass according to claim 17, wherein the silicate glass is substantially free of at least one of antimony oxide and arsenic oxide.

26. The silicate glass according to claim 17, wherein the silicate glass comprises 62-70 mol. % SiO₂;

up to 9.01 mol% B₂O₃;

0-15 mol % Li₂O;

0-18 mol % K₂O;

less than 3 mol% MgO;

less than 3 mol % CaO; and

0-5 mol % ZrO₂.