Tough glass composite and method
Embodiments of a glass substrate including an alkali-containing bulk and an alkali-depleted surface layer, including a substantially homogenous composition with at least 51 mol % Al 2 O 3 are disclosed. In some embodiments, the alkali-depleted surface layer includes about 0.5 atomic % alkali or less. The alkali-depleted surface layer can be substantially free of hydrogen and/or crystallites. Methods for forming a glass substrate with a modified surface layer are also provided.
1. A glass substrate comprising:
an alkali-containing bulk comprising Al 2 O 3 and SiO 2 ; and
an alkali-depleted surface layer comprising Al 2 O 3 and SiO 2 ,
wherein:
the alkali-depleted surface layer is substantially amorphous such that the alkali-depleted surface layer is less than 1% crystalline phase by volume;
the alkali-depleted surface layer has a substantially homogenous composition comprising 57 mol % or more Al 2 O 3 ;
the alkali-depleted surface layer exhibits a cracking probability of 50% or less for a Vicker's indentation load of 10N; and
the alkali-depleted surface layer is formed by thermal poling of the glass substrate.
2. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises about 0.5 atomic % alkali or less.
3. The glass substrate according to claim 1 , wherein the alkali-containing bulk comprises an alkali-metal oxide or an alkaline-earth oxide selected from Li 2 O, Na 2 O, K 2 O, Rb 2 O, Cs 2 O, MgO, CaO, SrO, and BaO, and combinations thereof.
4. The glass substrate according to claim 1 further comprising one or more mobile transition metal oxides.
5. The glass substrate according to claim 4 comprising Ag 2 O.
6. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises Al 2 O 3 in the range from 57 mol % to 90 mol %.
7. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises Al 2 O 3 in the range from 57 mol % to 80 mol %.
8. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises Al 2 O 3 in the range from 57 mol % to 70 mol %.
9. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises Al 2 O 3 in the range from 57 mol % to 65 mol %.
10. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises a binary Al 2 O 3 -SiO 2 composition.
11. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer has a thickness in the range from about 10 nm to about 10,000 nm.
12. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer has a thickness in the range from about 10 nm to about 1200 nm.
13. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer has a thickness in the range from about 10 nm to about 600 nm.
14. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer exhibits a cracking probability of 50% or less for a Vicker's indentation load of 30N.
15. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer exhibits a cracking probability of 50% or less for a Vicker's indentation load of 50N.
16. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer has less than 0.1 atomic % of H.
17. The glass substrate according to claim 1 , wherein the alkali-depleted surface layer comprises 0.5 atomic % H or less.