Glasses and glass ceramics including a metal oxide concentration gradient
A glass-based article may include from about 45 mol. % to about 80 mol. % SiO 2 ; from about 0 mol. % to about 10 mol. % Na 2 O; less than about 5 mol. % K 2 O; a non-zero amount of Al 2 O; and an amorphous phase and a crystalline phase. The article may further in include a stress profile comprising a surface compressive stress (CS) and a maximum central tension (CT). A ratio of Li 2 O (mol. %) to R 2 O (mol. %) in the article is from about 0.5 to about 1, where R 2 O is the sum of Li 2 O, Na 2 O, and K 2 O in the article. CT may be greater than or equal to about 50 MPa and less than about 100 MPa. CS may be greater than 2.0·CT. A depth of compression (DOC) of the stress profile may be greater than or equal to 0.14·t and less than or equal to 0.25·t, where t is the thickness of the article.
1. A glass article comprising:
SiO 2 in an amount from 68 mol % to 75 mol %;
Al 2 O 3 in an amount from 5 mol % to 20 mol %;
Li 2 O in an amount from 2 mol % to 10 mol %;
Na 2 O in an amount from 2 mol % to 5 mol %;
a non-zero amount of K 2 O up to 2 mol %;
a non-zero amount of alkaline earth metal oxides up to 14 mol %, the alkaline earth metal oxides comprising MgO; and
B 2 O 3 in an amount from 1 mol % to 10 mol %, wherein:
R 2 O —Al 2 O 3 is from −5 to 0 and R 2 O is Li 2 O+K 2 O+Na 2 O; and
a ratio of Li 2 O to R 2 O is 0.5-1.0.
2. The glass article of claim 1 , wherein Li 2 O+Na 2 O+K 2 O is from 5 mol % to 15 mol %.
3. The glass article of claim 1 , comprising ZrO 2 , wherein the ZrO 2 is present in an amount less than 1 mol %.
4. The glass article of claim 1 , comprising P 2 O 5 in an amount from 0.1 mol % to 8 mol %.
5. The glass article of claim 1 , comprising up to 10 mol % alkaline earth metal oxide.
6. The glass article of claim 1 , comprising from 1 mol % to 6 mol % B 2 O 3 .
7. The glass article of claim 1 , comprising from 4 mol % to 10 mol % Li 2 O.
8. A glass article comprising:
SiO 2 in an amount from 68 mol % to 75 mol %;
Al 2 O 3 in an amount from 5 mol % to 20 mol %;
Li 2 O in an amount from 4 mol % to 10 mol %;
Na 2 O in an amount from 2 mol % to 5 mol %;
a non-zero amount of K 2 O up to 2 mol %;
a non-zero amount of alkaline earth metal oxides up to 14 mol %, the alkaline earth metal oxides comprising MgO and CaO; and
B 2 O 3 in an amount from 1 mol % to 10 mol %, wherein a ratio of Li 2 O to R 2 O is 0.5-1.0 and R 2 O is Li 2 O+K 2 O+Na 2 O.
9. The glass article of claim 8 , wherein Li 2 O+Na 2 O+K 2 O is from 5 mol % to 15 mol %.
10. The glass article of claim 8 , comprising ZrO 2 , wherein the ZrO 2 is present in an amount less than 1 mol %.
11. The glass article of claim 8 , comprising P 2 O 5 in an amount from 0.1 mol % to 8 mol %.
12. The glass article of claim 8 , comprising up to 10 mol % alkaline earth metal oxide.
13. The glass article of claim 8 , comprising from 1 mol % to 6 mol % B 2 O 3 .
14. The glass article of claim 9 , wherein R 2 O —Al 2 O 3 is from −5 to 0.