High strength glass-ceramics
In embodiments, a precursor glass composition comprises from about 55 wt. % to about 80 wt. % SiO 2 ; from about 2 wt. % to about 20 wt. % Al 2 O 3 ; from about 5 wt. % to about 20 wt. % Li 2 O; greater than 0 wt % to about 3 wt. % Na 2 O; a non-zero amount of P 2 O 5 less than or equal to 4 wt. %; and from about 0.2 wt. % to about 15 wt. % ZrO 2 . In embodiments, ZrO 2 (wt. %)+P 2 O 5 (wt. %) is greater than 3. When the precursor glass composition is converted to a glass-ceramic article, the glass-ceramic article may include grains having a longest dimension of less than 100 nm.
1. A glass-ceramic article, comprising in oxide wt %:
at least 55 wt % and no more than 80 wt % silica (SiO 2 );
at least 12 wt % and no more than 20 wt % lithia (Li 2 O);
at least 2 wt % and no more than 6 wt % phosphorous pentoxide (P 2 O 5 );
at least 3 wt % and no more than 15 wt % zirconia (ZrO 2 );
wherein the glass-ceramic article comprises a crystalline phase and a glass phase;
wherein the crystalline phase comprises lithium disilicate (Li 2 Si 2 O 5 );
wherein the lithium disilicate is a primary crystalline phase;
wherein the crystal phase further comprises lithiophosphate (Li 3 PO 4 ); and
wherein the glass-ceramic article is transparent such that average transmittance of the glass-ceramic article along a 1 mm pathlength is 85% or greater for light between 400 nm to 1000 nm.
2. The glass-ceramic article of claim 1 , wherein the glass-ceramic article comprises a central tension of at least 10 MPa.
3. The glass-ceramic article of claim 1 , wherein crystals of the lithium disilicate are randomly-oriented and interlocked.
4. The glass-ceramic article of claim 3 , wherein the glass-ceramic article has a fracture toughness 1 MPa·m 1/2 greater.
5. The glass-ceramic article of claim 1 , wherein grains in the glass-ceramic article have a length of less than 100 nm.
6. A glass-ceramic article, comprising in oxide wt %:
at least 55 wt % and no more than 80 wt % silica (SiO 2 );
at least 12 wt % and no more than 20 wt % lithia (Li 2 O);
at least 2 wt % and no more than 6 wt % phosphorous pentoxide (P 2 O 5 );
at least 3 wt % and no more than 15 wt % zirconia (ZrO 2 );
wherein the glass-ceramic article comprises a crystalline phase and a glass phase;
wherein the crystalline phase comprises lithium disilicate (Li 2 Si 2 O 5 );
wherein the lithium disilicate is a primary crystalline phase and wherein the glass-ceramic article comprises at least 40 wt % and no more than 60 wt % lithium disilicate;
wherein the glass-ceramic article comprises at least 10 wt % and no more than 30 wt % of the glass phase; and
wherein the glass-ceramic article has a fracture toughness of 1 MPa·m 1/2 or gar, and
wherein the glass-ceramic article comprises a central tension of at least 10 MPa.
7. The glass-ceramic article of claim 6 , further comprising alumina (Al 2 O 3 ).
8. The glass-ceramic article of claim 6 , wherein crystals of the lithium disilicate are randomly-oriented and interlocked.
9. The glass-ceramic article of claim 6 , wherein grains in the glass-ceramic article have a length of less than 100 nm.
10. The glass-ceramic article of claim 9 , wherein the glass-ceramic article is transparent such that average transmittance of the glass-ceramic article along a 1 mm pathlength is 85% or greater for light between 400 nm to 1000 nm.
11. A glass-ceramic article, comprising in oxide wt %:
at least 55 wt % and no more than 80 wt % silica (SiO 2 );
at least 12 wt % and no more than 20 wt % lithia (Li 2 O);
at least 2 wt % and no more than 6 wt % phosphorous pentoxide (P 2 O 5 );
at least 3 wt % and no more than 15 wt % zirconia (ZrO 2 );
wherein the glass-ceramic article comprises a crystalline phase and a glass phase;
wherein the crystalline phase comprises lithium disilicate (Li 2 Si 2 O 5 );
wherein the lithium disilicate is a primary crystalline phase;
wherein grains in the glass-ceramic article have a length of less than 100 nm, thereby facilitating transparency thereof;
wherein the glass-ceramic article is transparent such that average transmittance of the glass-ceramic article along a 1 mm pathlength is 85% or greater for light between 400 nm to 1000 nm;
wherein crystals of the lithium disilicate are interlocking, thereby influencing mechanical properties of the glass-ceramic article; and
wherein the glass-ceramic article has fracture toughness of 1 MPa·m 1/2 or greater.
12. The glass-ceramic article of claim 11 , wherein the glass-ceramic article comprises a thickness of less than or equal to 5 mm and at least 200 μm.
13. The glass-ceramic article of claim 11 , wherein the glass-ceramic article comprises a central tension of at least 10 MPa.
14. The glass-ceramic article of claim 11 , wherein the glass-ceramic article comprises at least 10 wt % and no more than 30 wt % of the glass phase.
15. The glass-ceramic article of claim 11 , wherein the crystal phase further comprises lithiophosphate (Li 3 PO 4 ).
16. The glass-ceramic article of claim 11 , wherein the zirconia is at least 4 wt %.
17. The glass-ceramic article of claim 11 , wherein the silica is at least 65 wt %.
18. The glass-ceramic article of claim 11 , wherein the glass-ceramic article comprises at least 40 wt % and no more than 60 wt % lithium disilicate.
19. The glass-ceramic article of claim 11 , wherein the glass-ceramic article has fracture toughness of 1.2 MPa·m 1/2 or greater.
20. The glass-ceramic article of claim 11 , wherein the glass-ceramic article has a Vickers hardness of at least 600 kgf/mm 2 and no more than 900 kgf/mm 2 .