Crack and scratch resistant glass and enclosures made therefrom
A glass and an enclosure, including windows, cover plates, and substrates for mobile electronic devices comprising the glass. The glass has a crack initiation threshold that is sufficient to withstand direct impact, has a retained strength following abrasion that is greater than soda lime and alkali aluminosilicate glasses, and is resistant to damage when scratched. The enclosure includes cover plates, windows, screens, and casings for mobile electronic devices and information terminal devices.
1. An aluminoborosilicate glass, the aluminoborosilicate glass comprising at least 50 mol % SiO 2 , less than 10 mol % B 2 O 3 , and at least 8 mol % Na 2 O, wherein the aluminoborosilicate glass is free of lithium and ion exchangeable, wherein a ratio
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
∑
modifiers
(
mol
%
)
>
1
,
wherein Al 2 O 3 (mol %) >B 2 O 3 (mol %) and the modifers are Na 2 O and, optionally, at least one of one or more alkali metal oxide R 2 O other than Na 2 O and Li 2 O and one or more alkaline earth oxide RO, wherein the aluminoborosilicate glass has a Young's modulus of less than about 69 GPa, and wherein −5.7 mol %<Σmodifiers−Al 2 O 3 <2.99 mol %.
2. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass has a Vickers median/radial crack initiation threshold of at least 500 gf.
3. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass exhibits indentation deformation by densification deformation when submitted to an indentation load of at least 500 gf and is free of subsurface shear faulting.
4. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass has a molar volume of at least 27 cm 3 /mol.
5. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass is down-drawable.
6. The aluminoboro silicate glass of claim 1 , wherein the at least one modifier includes at least one alkali metal oxide other than Na 2 O.
7. The aluminoborosilicate glass of claim 1 , wherein 0.9<(Na 2 O(mol %)+R 2 O(mol %))/Al 2 O 3 (mol %)<1.3.
8. The aluminoborosilicate glass of claim 7 , wherein B 2 O 3 (mol %)>Na 2 O(mol %)+R 2 O(mol %)−Al 2 O 3 (mol %)).
9. The aluminoborosilicate glass of claim 7 , wherein B 2 O 3 (mol %)>2(Na 2 O(mol %)+R 2 O(mol %)−Al 2 O 3 (mol %)).
10. An aluminoborosilicate glass, the aluminoborosilicate glass comprising: 50-72 mol % SiO 2 ; 9-17 mol % Al 2 O 3 ; less than 10 mol % B 2 O 3 ; 8-16 mol % Na 2 O; and 0-4 mol % K 2 O, wherein the ratio
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
∑
modifiers
(
mol
%
)
>
1
,
wherein Al 2 O 3 (mol %)>B 2 O 3 (mol %) and the modifiers are Na 2 O and, optionally, at least one of one or more alkali metal oxide R 2 O other than Na 2 O and Li 2 O and one or more alkaline earth oxide RO, wherein the aluminoborosilicate glass is free of lithium, is ion exchangeable and has a Young's modulus of less than about 69 GPa, and wherein −5.7 mol %<Σmodifiers−Al 2 O 3 <2.99 mol %.
11. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass is ion exchanged and has a Vickers median/radial crack initiation threshold of at least 10 kgf.
12. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass exhibits indentation deformation by densification deformation when submitted to an indentation load of at least 500 gf and is free of subsurface shear faulting.
13. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass has a Vickers median/radial crack initiation threshold of at least 500 gf.
14. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass has a molar volume of at least 27 cm 3 /mol.
15. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass is ion exchanged and is free of chips having a size greater than two times a width w of a scratch formed by a Knoop diamond at a load of at least 5 N.
16. An aluminoborosilicate glass, the aluminoborosilicate glass comprising at least 58 mol % SiO 2 , less than 10 mol % B 2 O 3 , and at least 8 mol % Na 2 O, wherein the aluminoborosilicate glass is free of lithium and ion exchangeable, wherein a ratio
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
∑
modifiers
(
mol
%
)
>
1
,
wherein Al 2 O 3 (mol %)>B 2 O 3 (mol %) and the modifiers are Na 2 O and, optionally, at least one of one or more alkali metal oxide R 2 O other than Na 2 O and Li 2 O and one or more alkaline earth oxide RO, wherein the aluminoborosilicate glass has a Young's modulus of less than about 69 GPa, and wherein −5.7 mol %<Σmodifiers−Al 2 O 3 <2.99 mol %.
17. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass is a strengthened aluminoborosilicate glass.
18. The aluminoborosilicate glass of claim 17 , wherein the strengthened aluminoborosilicate glass is an ion exchanged aluminoborosilicate glass.
19. The aluminoborosilicate glass of claim 18 , wherein the ion exchanged aluminoborosilicate glass has a Vickers median/radial crack initiation threshold of at least 10 kgf.
20. The aluminoborosilicate glass of claim 19 , wherein the ion exchanged aluminoborosilicate glass has a Vickers median/radial crack initiation threshold of at least 20 kgf.
21. The aluminoborosilicate glass of claim 20 , wherein the ion exchanged aluminoborosilicate glass has a Vickers median/radial crack initiation threshold of at least 30 kgf.
22. The aluminoborosilicate glass of claim 18 , wherein the ion exchanged aluminoborosilicate glass exhibits indentation deformation by densification deformation when submitted to an indentation load of at least 500 gf and is free of subsurface shear faulting.
23. The aluminoborosilicate glass of claim 18 , wherein the ion exchanged aluminoborosilicate glass has a compressive stress of at least about 400 MPa and a depth of layer of at least about 15 μm.
24. The aluminoborosilicate glass of claim 18 , wherein the ion exchanged aluminoborosilicate glass is substantially non-frangible.
25. The aluminoborosilicate glass of claim 18 , wherein the ion exchanged aluminoborosilicate glass is free of lateral damage extending more than twice a width w of a scratch formed by a Knoop diamond at a load of at least 5 N.
26. The aluminoborosilicate glass of claim 1 , wherein
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
∑
modifiers
(
mol
%
)
>
1.45
.
27. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass is free of at least one of arsenic, antimony, and barium.
28. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass has a liquidus viscosity of at least 130 kilopoise.
29. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass is free of non-bridging oxygens.
30. The aluminoborosilicate glass of claim 1 , wherein the aluminoborosilicate glass has a thickness in a range from about 0.1 mm up to about 2.0 mm.
31. The aluminoborosilicate glass of claim 11 , wherein the Vickers median/radial crack initiation threshold is at least 20 kgf.
32. The aluminoborosilicate glass of claim 11 , wherein the Vickers median/radial crack initiation threshold is at least 30 kgf.
33. The aluminoborosilicate glass of claim 10 , wherein the aluminoborosilicate glass is ion exchanged.
34. The aluminoborosilicate glass of claim 33 , wherein the ion exchanged aluminoborosilicate glass has a compressive stress of about 400 MPa and a depth of layer of at least 15 μm.
35. The aluminoborosilicate glass of claim 33 , wherein the ion exchanged aluminoborosilicate glass is substantially non-frangible.
36. The aluminoborosilicate glass of claim 10 , wherein 0.9 mol %<(Na 2 O(mol %)+R 2 O(mol %))/Al 2 O 3 (mol %) <1.3 mol %.
37. The aluminoborosilicate glass of claim 36 , wherein B 2 O 3 (mol %)>Na 2 O(mol %)+R 2 O(mol %)−Al 2 O 3 (mol %).
38. The aluminoborosilicate glass of claim 36 , wherein B 2 O 3 (mol %)>2(Na 2 O(mol %)+R 2 O(mol %)−Al 2 O 3 (mol %)).