Zircon compatible, ion exchangeable glass with high damage resistance
An ion exchangeable glass having a high degree of resistance to damage caused by abrasion, scratching, indentation, and the like. The glass comprises alumina, B 2 O 3 , and alkali metal oxides, and contains boron cations having three-fold coordination. The glass, when ion exchanged, has a Vickers crack initiation threshold of at least 10 kilogram force (kgf).
1. A glass, the glass comprising:
66-74 mol % SiO 2 ;
at least about 10 mol % R 2 O, wherein R 2 O comprises 9-20 mol % Na 2 O;
9-22 mol % Al 2 O 3 , wherein Al 2 O 3 (mol %)<R 2 O(mol %); and
B 2 O 3 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≧3 mol %, and wherein the glass is ion exchangeable.
2. The glass of claim 1 , wherein the glass comprises at least 0.1 mol % of at least one of MgO and ZnO.
3. The glass of claim 1 , wherein the glass has a zircon breakdown temperature that is equal to a temperature at which the glass has a viscosity in a range from about 30 kPoise to about 40 kPoise.
4. The glass of claim 1 , wherein the glass comprises at least about 2.7 mol % B 2 O 3 .
5. The glass of claim 4 , wherein the glass comprises from about 2.7 mol % to about 4.5 mol % B 2 O 3 .
6. The glass of claim 1 , wherein at least 50% of the B 2 O 3 present in the glass comprises three-fold coordinated boron cations.
7. The glass of claim 1 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≦4.5 mol %.
8. The glass of claim 1 , wherein the glass comprises: from about 3 mol % to about 10 mol % B 2 O 3 ; from 0 mol % to about 5 mol % K 2 O; at least, 0.1 mol % MgO+ZnO, wherein 0≦MgO≦6 and 0≦ZnO≦6 mol %; and, optionally, at least one of CaO, BaO, and SrO, wherein 0 mol %≦CaO+SrO+BaO≦2 mol %.
9. The glass of claim 1 , wherein the glass is ion exchanged and has a layer under a compressive stress of at least about 600 MPa, the layer extending from a surface of the glass into the glass to a depth of layer of at least about 30 μm.
10. The glass of claim 9 , wherein the compressive stress is at least about 800 MPa.
11. The glass of claim 9 , wherein the glass has a Vickers crack initiation of at least about 10 kgf.
12. The glass of claim 11 , wherein the glass has a Vickers crack initiation threshold in a range from about 20 kgf to about 30 kgf.
13. The glass of claim 11 , wherein the glass has a Vickers crack initiation threshold in a range from about 30 kgf to about 35 kgf.
14. The glass of claim 1 , wherein the glass contains less than about 0.1 inclusion per pound of the glass, the inclusion having a size of at least about 50 μm.
15. The glass of claim 1 , wherein the glass is down-drawn.
16. The glass of claim 1 , wherein the glass has an anneal point and a strain point, and wherein the glass is fast-cooled from a temperature that is above the anneal point or the strain point.
17. A glass, the glass comprising:
at least about 50 mol % SiO 2 ;
at least about 10 mol % R 2 O, wherein R 2 O comprises 9-20 mol % Na 2 O and 0-0.5 mol % Li 2 O;
Al 2 O 3 ; and
2.7-4.5 mol % B 2 O 3 , wherein B 2 O 3 −(R 2 O−Al 2 O 3 )≧3 mol %, and
wherein the glass has a zircon breakdown temperature that is equal to the temperature at which the glass has a viscosity in a range from about 25 kPoise to about 40 kPoise.
18. The glass of claim 17 , wherein the glass comprises at least about 0.1 mol % of at least one of MgO and ZnO.
19. The glass of claim 17 , wherein the glass comprises three-fold coordinated boron cations.
20. The glass of claim 17 , wherein at least 50% of the B 2 O 3 present in the glass comprises three-fold coordinated boron cations.
21. The glass of claim 17 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≦4.5 mol %.
22. The glass of claim 17 , wherein the glass comprises: at least about 50 mol % SiO 2 , from about 9 mol % to about 22 mol % Al 2 O 3 ; 3 mol % to 4.5 mol % B 2 O 3 ; from 0 mol % to about 5 mol % K 2 O; at least 0.1 mol % MgO+ZnO, wherein 0≦MgO≦6 and 0≦ZnO≦6; and, optionally, at least one of CaO, BaO, and SrO, wherein 0 mol %≦CaO+SrO+BaO≦2 mol %.
23. The glass of claim 17 , wherein the glass forms at least a portion of a cover plate, a touch screen, a watch crystal, a solar concentrator, a window, a screen, or a container.
24. The glass of claim 17 , wherein the glass is ion exchanged and has a layer under a compressive stress of at least about 600 MPa, the layer extending from a surface of the glass into the glass to a depth of layer of at least about 30 μm.
25. The glass of claim 24 , wherein the compressive stress is at least about 800 MPa.
26. The glass of claim 24 , wherein the glass has a Vickers crack initiation threshold of at least about 10 kgf.
27. The glass of claim 26 , wherein the glass has a Vickers crack initiation threshold in a range from about 20 kgf to about 30 kgf.
28. The glass of claim 26 , wherein the glass has a Vickers crack initiation threshold in a range from about 30 kgf to about 35 kgf.
29. The glass of claim 17 , wherein the glass contains less than about 0.1 inclusion per pound of the glass, the inclusion having a size of at least about 50 μm.
30. The glass of claim 17 , wherein the glass is down-drawn.
31. The glass of claim 17 , wherein the glass has an anneal point and a strain point, and wherein the glass is fast-cooled from a temperature that is above the anneal point or the strain point.
32. A glass comprising:
66-74 mol % SiO 2 ;
at least about 10 mol % R 2 O, wherein R 2 O comprises 9-20 mol % Na 2 O;
Al 2 O 3 , wherein Al 2 O 3 (mol %)<R 2 O(mol %); and
at least 2.7 mol % B 2 O 3 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≦3 mol %.
33. The glass of claim 32 , wherein the glass comprises at least 0.1 mol % of at least one of MgO and ZnO.
34. The glass of claim 32 , wherein the glass comprises from 2.7 mol % to 4.5 mol % B 2 O 3 .
35. The glass of claim 32 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≦4.5 mol %.
36. The glass of claim 32 , wherein at least 50% of the B 2 O 3 present in the glass comprises three-fold coordinated boron cations.
37. The glass of claim 32 , wherein the glass comprises: from about 9 mol % to about 22 mol % Al 2 O 3 ; from about 3 mol % to about 10 mol % B 2 O 3 ; from 0 mol % to about 5 mol % K 2 O; at least 0.1 mol % MgO+ZnO, wherein 0≦MgO≦6 and 0≦ZnO≦6; and, optionally, at least one of CaO, BaO, and SrO, wherein 0 mol %≦CaO+SrO+BaO≦2 mol %.
38. The glass of claim 32 , wherein the glass is ion exchanged and has a layer under a compressive stress of at least about 600 MPa, the layer extending from a surface of the glass into the glass to a depth of layer of at least about 30 μm.
39. The glass of claim 38 , wherein the compressive stress is at least about 800 MPa.
40. The glass of claim 32 , wherein the glass is ion exchanged and has a Vickers crack initiation threshold in a range from about 20 kgf to about 30 kgf.
41. The glass of claim 32 , wherein the glass is ion exchanged and has a Vickers crack initiation threshold in a range from about 30 kgf to about 35 kgf.
42. The glass of claim 32 , wherein the glass contains less than about 0.1 inclusion per pound of the glass, the inclusion having a size of at least about 50 μm.
43. The glass of claim 32 , wherein the glass is down-drawn.
44. The glass of claim 32 , wherein the glass has an anneal point and a strain point, and wherein the glass is fast-cooled from a temperature that is above the anneal point or the strain point.
45. The glass of claim 32 , wherein the glass is ion exchanged and forms at least a portion of a cover plate, a touch screen, a watch crystal, a solar concentrator, a window, a screen, or a container.
46. A glass comprising:
66-74 mol % SiO 2 ;
at least about 10 mol % R 2 O, wherein R 2 O comprises Na 2 O;
9-22 mol % Al 2 O 3 ;
at least 2.7 mol % B 2 O 3 , wherein B 2 O 3 −(R 2 O−Al 2 O 3 )≧3 mol %; and
at least 0.1 mol % of at least one of MgO and ZnO.
47. The glass of claim 46 , wherein the glass has a zircon breakdown temperature that is equal to a temperature at which the glass has a viscosity in a range from about 30 kPoise to about 40 kPoise.
48. The glass of claim 46 , wherein the glass comprises from 2.7 mol % to about 4.5 mol % B 2 O 3 .
49. The glass of claim 46 , wherein at least 50% of the B 2 O 3 present in the glass comprises three-fold coordinated boron cations.
50. The glass of claim 46 , wherein B 2 O 3 (mol %)−(R 2 O(mol %)−Al 2 O 3 (mol %))≦4.5 mol %.
51. The glass of claim 46 , wherein the glass comprises: from about 3 mol % to about 10 mol % B 2 O 3 ; from about 9 mol % to about 20 mol % Na 2 O; from 0 mol % to about 5 mol % K 2 O; at least 0.1 mol % MgO+ZnO, wherein 0≦MgO≦6 and 0≦ZnO≦6 mol %; and, optionally, at least one of CaO, BaO, and SrO, wherein 0 mol %≦CaO+SrO+BaO≦2 mol %.
52. The glass of claim 46 , wherein the glass is ion exchanged and has a layer under a compressive stress of at least about 600 MPa, the layer extending from a surface of the glass into the glass to a depth of layer of at least about 30 μm.
53. The glass of claim 52 , wherein the compressive stress is at least about 800 MPa.
54. The glass of claim 52 , wherein the glass has a Vickers crack initiation threshold of at least about 10 kgf.
55. The glass of claim 54 , wherein the glass has a Vickers crack initiation threshold in a range from about 20 kgf to about 30 kgf.
56. The glass of claim 54 , wherein the glass has a Vickers crack initiation threshold in a range from about 30 kgf to about 35 kgf.
57. The glass of claim 46 , wherein the glass contains less than about 0.1 inclusion per pound of the glass, the inclusion having a size of at least about 50 μm.
58. The glass of claim 46 , wherein the glass is down-drawn.
59. The glass of claim 46 , wherein the glass has an anneal point and a strain point, and wherein the glass is fast-cooled from a temperature that is above the anneal point or the strain point.