Alkaline earth alumino-silicate glass compositions with improved chemical and mechanical durability

1. A glass composition comprising:

from 67 mol. % to about 75 mol. % SiO 2 ;

from about 6 mol. % to about 10 mol. % Al 2 O 3 ;

from about 5 mol. % to about 12 mol. % alkali oxide, wherein the alkali oxide comprises Na 2 O and K 2 O and the K 2 O is present in an amount less than or equal to 0.5 mol. %; and

from about 9 mol. % to about 15 mol. % of alkaline earth oxide, the alkaline earth oxide comprising greater than 0 mol. % and less than or equal to 3 mol. % MgO and from about 2 mol. % to about 7 mol% CaO, wherein a ratio of a concentration of MgO to the sum of the concentration of divalent cations (MgO:ΣRO) is less than 0.3 and the glass composition is susceptible to strengthening by ion-exchange.

2. The glass composition of claim 1 wherein SiO 2 is present in the glass composition in a concentration from about 67 mol. % to about 73 mol. %.

3. The glass composition of claim 1 , wherein Al 2 O 3 is present in the glass composition in a concentration from about 7 mol. % to about 10 mol. %.

4. The glass composition of claim 1 , wherein the glass composition comprises less than 1 mol. % B 2 O 3 .

5. The glass composition of claim 1 , wherein the glass composition is free from boron and compounds of boron.

6. The glass composition of claim 1 , wherein the glass composition is free from barium and compounds of barium.

7. The glass composition of claim 1 , wherein the alkali metal oxide further comprises Li 2 O in an amount from about 1 mol. % to about 3 mol. %.

8. The glass composition of claim 1 , wherein the Na 2 O is present in an amount from about 3.5 mol. % to about 8 mol. %.

9. The glass composition of claim 1 , wherein the alkaline earth oxide is present in an amount from about 10 mol. % to about 14 mol. %.

10. The glass composition of claim 1 , wherein MgO is present in an amount greater than 0 mol. % and less than or equal to 2.5 mol. %.

11. The glass composition of claim 1 further comprising ZrO 2 in an amount less than or equal to about 1.5 mol. %.

12. The glass composition of claim 1 , further comprising ZnO in an amount less than or equal to about 2.0 mol. %.

13. The glass composition of claim 1 further comprising SnO 2 in an amount less than or equal to about 0.3 mol. %.

14. The glass composition of claim 1 , wherein the glass composition is substantially free from phosphorous and compounds of phosphorous.

15. The glass composition of claim 1 , wherein the glass composition has a liquidus viscosity greater than or equal to 85 kP.

16. The glass composition of claim 1 , wherein the glass composition has at least a class S3 acid resistance according to DIN 12116 both before and after ion-exchange strengthening.

17. The glass composition of claim 1 , wherein the glass composition has a class A1 base resistance according to ISO 695 both before and after ion-exchange strengthening.

18. The glass composition of claim 1 , wherein the glass composition has a type HGA1 hydrolytic resistance according to ISO 720 after ion exchange strengthening.

19. The glass composition of claim 1 , wherein the glass composition has a Type HGA1 hydrolytic resistance according to ISO 720 before strengthening by ion exchange and after strengthening by ion exchange.

20. The glass composition of claim 1 , wherein the alkaline earth oxide comprises at least one of SrO and BaO.

21. The glass composition of claim 20 , wherein the alkaline earth oxide comprises SrO in an amount greater than or equal to about 1 mol. % and less than or equal to about 2 mol. %.

22. The glass composition of claim 20 , wherein the alkaline earth oxide comprises SrO in an amount greater than 0 mol. % and less than or equal to about 6 mol. %.

23. A glass composition comprising:

from 67 mol. % to about 75 mol. % SiO 2 ;

from about 6 mol. % to about 10 mol. % Al 2 O 3 ;

from about 5 mol. % to about 12 mol. % alkali oxide, wherein the alkali oxide comprises K 2 O in an amount less than or equal to 0.5 mol. %;

from about 9 mol. % to about 15 mol. % of alkaline earth oxide, wherein the alkaline earth oxide comprises greater than 0 mol. % and less than or equal to 3 mol, % MgO, from about 2 mol. % to about 7 mol% CaO, at least one of SrO and BaO, wherein:

a ratio of a concentration og MgO to the sum of the concentration of divalent cations (MgO:ΣRO) is less than 0.3;

the glass composition is free from boron and compounds of boron;

the glass composition is free from phosphorous and compounds of phosphorous; and

the glass composition is ion exchangeable to a depth of layer greater than or equal to about 15 μm with a corresponding compressive stress greater than or equal to about 250 MPa.

24. The glass composition of claim 23 , wherein the alkali oxide comprises Na 2 O in an amount from about 3.5 mol. % to about 8 mol. %.

25. The glass composition of claim 23 , wherein the alkaline earth oxide comprises SrO in an amount greater than or equal to about 1 mol. % and less than or equal to about 2 mol. %.

26. The glass composition of claim 23 , wherein the alkaline earth oxide comprises SrO in an amount greater than 0 mol. % and less than or equal to about 6 mol. %.

27. The glass composition of claim 23 , wherein the glass composition is free from barium and compounds of barium.

28. The glass composition of claim 23 , wherein a concentration of Al 2 O 3 is about 7 mol % to about 10 mol. %.

29. The glass composition of claim 23 , wherein the alkali metal oxide further comprises Li 2 O in an amount from about 1 mol. % to about 3 mol. %.

30. The glass composition of claim 23 , wherein the alkaline earth oxide is present in an amount from about 10 mol. % to about 14 mol. %.

31. The glass composition of claim 23 , wherein the glass composition comprises:

from about 2 mol. % to about 5 mol. % CaO; and

from about 3 mol. % to about 6 mol. % SrO.

32. The glass composition of claim 23 further comprising ZrO 2 in an amount less than or equal to about 1.5 mol. %.

33. The glass composition of claim 23 , further comprising ZnO in an amount less than or equal to about 2.0 mol. %.

34. The glass composition of claim 23 , wherein the glass composition has a liquidus viscosity greater than or equal to 85 kP.

35. The glass composition of claim 23 , wherein the glass composition has at least a class S3 acid resistance according to DIN 2116 both before and after ion-exchange strengthening.

36. The glass composition of claim 23 , wherein the glass composition has a class A1 base resistance according to ISO 695 both before and after ion-exchange strengthening.

37. The glass composition of claim 23 , wherein the glass composition has a type HGA1 hydrolytic resistance according to ISO 720 after ion-exchange strengthening.

38. The glass composition of claim 23 , wherein the glass composition has a Type HGA1 hydrolytic resistance according to ISO 720 before strengthening by ion exchange and after strengthening by ion exchange.

39. The glass composition of claim 23 , wherein MgO is present in an amount greater than 0 mol. % and less than or equal to 2.5 mol. %.

40. The glass composition of claim 39 , wherein the glass composition further comprises ZnO in an amount less than or equal to 2.0 mol. %.

41. The glass composition of claim 39 , wherein the glass composition is free from zinc and compounds containing zinc.

42. The glass composition of claim 39 , wherein the glass composition further comprises Li 2 O in an amount greater than or equal to 1 mol. % and less than or equal to 3 mol. %.

43. The glass composition of claim 39 , wherein the glass composition is free from lithium and compounds containing lithium.

44. The glass composition of claim 39 , wherein the glass composition comprises:

from about 5 mol. % to about 6 mol. % CaO; and

from about 2 mol. % to about 4 mol. % SrO.

45. A glass article formed from glass having a composition comprising:

from 67 mol. % to about 75 mol. % SiO 2 ;

from about 6 mol. % to about 10 mol. % Al 2 O 3 ;

from about 5 mol. % to about 12 mol. % alkali oxide, wherein the alkali oxide comprises Na 2 O and K 2 O and the K 2 O is present in an amount less than or equal to 0.5 mol. %;

from about 9 mol. % to about 15 mol. % of alkaline earth oxide, the Alkaline earth oxide comprising greater than 0 mol. % and less than or equal to 3.0 mol. % MgO And from about 2 mol. % to about 7 mol.% CaO, wherein a ratio of a concentration of MgO to the sum of the concentration of divalent cations (MgO:ΣRO) is less than 0.3, wherein the composition is free from boron and compounds of boron and the glass article has:

at least a class S3 acid resistance according to DIN 12116;

a class A1 base resistance according to ISO 695; and

a type HGA1 hydrolytic resistance according to ISO 720.

46. The glass article of claim 45 , wherein the glass article has a coefficient of thermal expansion less than or equal to 70×10 −7 K −1 .

47. The glass composition of claim 45 , wherein the glass composition is substantially free from phosphorous and compounds of phosphorous.

48. The glass article of claim 45 , wherein the glass article has a compressive stress greater than or equal to about 250 MPa.

49. The glass article of claim 48 , wherein the glass article has a depth of layer greater than or equal to about 15 μm.