Glass compositions with improved chemical and mechanical durability
The embodiments described herein relate to chemically and mechanically durable glass compositions and glass articles formed from the same. In another embodiment, a glass composition may include from about 70 mol. % to about 80 mol. % SiO 2 ; from about 3 mol. % to about 13 mol. % alkaline earth oxide; X mol. % Al 2 O 3 ; and Y mol. % alkali oxide. The alkali oxide may include Na 2 O in an amount greater than about 8 mol. %. A ratio of Y:X may be greater than 1 and the glass composition may be free of boron and compounds of boron. In some embodiments, the glass composition may also be free of phosphorous and compounds of phosphorous. Glass articles formed from the glass composition may have at least a class S3 acid resistance according to DIN 12116, at least a class A2 base resistance according to ISO 695, and a type HGA1 hydrolytic resistance according to ISO 720.
1. A glass composition comprising:
from 72 mol. % to about 78 mol. % SiO 2 ;
from about 4 mol. % to about 8 mol. % alkaline earth oxide, the alkaline earth oxide comprising CaO;
X mol. % Al 2 O 3 , wherein X is from about 5 and less than 7; and
Y mol. % alkali oxide, wherein the alkali oxide comprises Na 2 O in an amount from about 8 mol. %, and the glass composition is free of boron and compounds of boron, wherein the glass composition has a coefficient of thermal expansion is less than 70×10 −7 K −1 over a temperature range from about room temperature to about 300° C.
2. The glass composition of claim 1 , wherein the SiO 2 is present in an amount less than or equal to 77 mol. %.
3. The glass composition of claim 1 , wherein the alkaline earth oxide comprises MgO and CaO and a ratio (CaO (mol. %)/(CaO (mol. %)+MgO (mol. %))) is less than or equal to 0.5.
4. The glass composition of claim 1 , wherein the alkaline earth oxide comprises from about 0.1 mol. % to less than or equal to about 1.0 mol. % CaO.
5. The glass composition of claim 1 , wherein the alkali oxide comprises from about 9 mol. % Na 2 O to about 15 mol. % Na 2 O.
6. The glass composition of claim 1 , wherein a ratio of Y:X is greater than 1.
7. The glass composition of claim 6 , wherein the ratio of Y:X is less than or equal to 2.
8. The glass composition of claim 1 , wherein a ratio of Y:X is greater than or equal to 1.3 and less than or equal to 2.0.
9. The glass composition of claim 1 , wherein the alkali oxide further comprises K 2 O in an amount less than or equal to 3 mol. %.
10. The glass composition of claim 1 wherein the glass composition is free of phosphorous and compounds of phosphorous.
11. The glass composition of claim 1 , wherein the alkali oxide comprises K 2 O in an amount from about 0.01 mol. % to about 1.0 mol. %.
12. A glass article formed from the glass composition of claim 1 , wherein the glass article has a type HGB1 hydrolytic resistance according to ISO 719.
13. The glass article formed from the glass composition of claim 12 , wherein the glass article has a type HGA1 hydrolytic resistance according to ISO 720 after ion exchange strengthening.
14. The glass article formed from the glass composition of claim 12 , wherein the glass article has a type HGA1 hydrolytic resistance according to ISO 720 before and after ion exchange strengthening.
15. The glass article of claim 12 , wherein the glass article has at least a class S3 acid resistance according to DIN 12116.
16. The glass article of claim 12 , wherein the glass article has at least a class A2 base resistance according to ISO 695.
17. The glass article of claim 12 , wherein the glass article is a pharmaceutical package.
18. The glass article of claim 12 , wherein the glass article is ion exchange strengthened.
19. The glass article of claim 12 further comprising a compressive stress layer with a depth of layer greater than or equal to 10 μm and a surface compressive stress greater than or equal to 250 MPa.