High strength glass-ceramics
A glass-ceramic article comprises in wt % on an oxide basis SiO 2 in an amount greater than or equal to 55 wt % and less than or equal to 80 wt %, Al 2 O 3 in an amount greater than or equal to 2 wt % and less than or equal to 20 wt %, Li 2 O in an amount greater than or equal to 5 wt % and less than or equal to 20 wt %, P 2 O 5 in an amount greater than 0 wt % and less than or equal to 6 wt %, and ZrO 2 in an amount greater than or equal to 0.2 wt % and less than or equal to 15 wt %. A sum of ZrO 2 and P 2 O 5 is greater than or equal to 3 wt %. The glass-ceramic article comprises a lithium disilicate (Li 2 Si 2 O 5 ) crystalline phase, where the lithium disilicate is between 40 wt % to 60 wt % of the glass-ceramic article.
1. A glass-ceramic article, comprising in wt % on an oxide basis:
SiO 2 in an amount greater than or equal to 55 wt % and less than or equal to 80 wt %;
Al 2 O 3 in an amount greater than or equal to 2 wt % and less than or equal to 20 wt %;
Li 2 O in an amount greater than or equal to 5 wt % and less than or equal to 20 wt %;
Na 2 O in an amount of greater than or equal to 1 wt % and less than or equal to 5 wt %;
P 2 O 5 in an amount greater than 0 wt % and less than or equal to 6 wt %;
ZrO 2 in an amount greater than or equal to 0.2 wt % and less than or equal to 15 wt %;
wherein a sum of ZrO 2 and P 2 O 5 is greater than or equal to 3 wt %;
wherein the glass-ceramic article comprises a lithium disilicate (Li 2 Si 2 O 5 ) crystalline phase,
wherein the lithium disilicate is between 40 wt % to 60 wt % of the glass-ceramic article; and
wherein grains of the glass-ceramic article have a longest dimension less than 100 nm and average transmittance of the glass-ceramic article along a 1 mm pathlength for wavelengths from 400 to 1000 nm is greater than 85%.
2. The glass-ceramic article of claim 1 , wherein grains of the lithium disilicate are randomly-oriented interlocked and the glass-ceramic article has fracture toughness greater than 1 MPa·m 1/2 .
3. The glass-ceramic article of claim 2 , wherein the glass-ceramic article has a compressive stress greater than 100 MPa, and a depth of layer of greater than or equal to 30 μm.
4. The glass-ceramic article of claim 3 , wherein Na 2 O is greater than 2 wt % and less than or equal to 5 wt %.
5. The glass-ceramic article of claim 4 , wherein Li 2 O is greater than 12 wt % and less than or equal to 20 wt %.
6. The glass-ceramic article of claim 5 , wherein P 2 O 5 is greater than or equal to 3 wt % and less than or equal to 6 wt %.
7. The glass-ceramic article of claim 6 , wherein the glass-ceramic article further comprises a petalite (LiAlSi 4 O 10 ) crystalline phase, and wherein the petalite and lithium disilicate are primary crystal phases of the glass-ceramic article.