Glasses having improved toughness and scratch resistance

• US 8,652,978 B2
• Filed: 08/17/2012
• Issued: 02/18/2014
• 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): Group, Karl
• Assistant Examiner(s): Bolden, Elizabeth A
• Application Number:
  US13/588,581
• Publication Number:
  US 20120308803A1
• Time in Patent Office: 550 Days
• Field of Search: 501/66, 501/69, 501/70, 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. alumina and boron oxide; and

b. at least one alkali metal oxide, wherein −

15 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

4 mol %, where R is at least one of Li, Na, K, Rb, and Cs, and R′

is at least one of Mg, Ca, Sr, and Ba;

c. 10≦

Al₂O₃+B₂O₃+ZrO₂≦

30; and

d. 14≦

R₂O+R′

O≦

25,

wherein the silicate glass comprises 62-70 mol. % SiO₂;

>

0-18 mol % Al₂O₃;

>

0-10 mol % B₂O₃;

0-15 mol % Li₂O;

6-14 mol % Na₂O;

0-18 mol % K₂O;

0-17 mol % MgO;

0-18 mol % CaO; and

0-5 mol % ZrO₂.

2. The silicate glass according to claim 1, wherein the silicate glass is substantially free of lithium.

3. The silicate glass according to claim 1, wherein the silicate glass is substantially free of antimony and arsenic oxides.

4. The silicate glass of claim 1, wherein −

5 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

4 mol %.

5. The silicate glass according to claim 1, wherein the silicate glass comprises:

64-66 mol % SiO₂;

8-12 mol % Al₂O₃;

1-10 mol % B₂O₃;

0-5 mol % Li₂O;

6-12 mol % Na₂O;

1-4 mol % K₂O;

0-4 mol % MgO;

0-6 mol % CaO; and

0-2 mol % ZrO₂.

6. The silicate glass according to claim 5, wherein 20 mol %≦

R₂O+R′

O≦

24 mol %.

7. The silicate glass according to claim 5, wherein 16 mol %≦

Al₂O₃+B₂O₃+ZrO₂≦

29 mol %.

8. 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.

9. The silicate glass according to claim 8, wherein the silicate glass has a brittleness of less than about 8.5 μ

m<sup>−

0.5</sup>.

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

11. The silicate glass according to claim 10, wherein the silicate glass is down-drawable.

12. The silicate glass according to claim 1, wherein the silicate glass has a thickness in a range from about 0.3 mm up to about 1.5 mm.

13. The silicate glass according to claim 1, wherein the silicate glass, when ion exchanged, 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.

14. The silicate glass according to claim 13, 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.

15. A silicate glass, the silicate glass having a toughness in a range from about 0.7 MPa m^0.5 up to about 1.2 MPa m^0.5, a brittleness of less than about 8.5 μ

m<sup>−

0.5</sup>, and wherein the silicate glass comprises Al₂O₃, B₂O₃, at least one alkali metal oxide, −

15 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

4 mol %, where R is at least one of Li, Na, K, Rb, and Cs, and R′

is at least one of Mg, Ca, Sr, and Ba, wherein the silicate glass comprises;

64-66 mol % SiO₂;

8-12 mol % Al₂O₃;

1-10 B₂O₃;

0-5 mol % Li₂O;

6-12 mol % Na₂O;

1-4 mol % K₂O;

0-4 mol % MgO;

0-6 mol % CaO; and

0-2 mol % ZrO₂.

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

R₂O+R′

O≦

24 mol %.

17. The silicate glass according to claim 15, wherein 16 mol %≦

Al₂O₃+B₂O₃+ZrO₂≦

29 mol %.