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

A glass composition comprising:

• from 67 mol. % to about 75 mol. % SiO2;
• from about 6 mol. % to about 10 mol. % Al2O3;
• from about 5 mol. % to about 12 mol. % alkali oxide, wherein the alkali oxide comprises K2O 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.

A glass article formed from glass having a composition comprising:

• from 67 mol. % to about 75 mol. % SiO2;
• from about 6 mol. % to about 10 mol. % Al2O3;
• from about 5 mol. % to about 12 mol. % alkali oxide, wherein the alkali oxide comprises Na2O and K2O and the K2O 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.