Ion exchangeable, transparent gahnite-spinel glass ceramics with high hardness and modulus
A transparent gahnite-spinel glass ceramic is provided. The glass ceramic includes a first crystal phase including (Mg x Zn 1−x )Al 2 O 4 where x is less than 1 and a second crystal phase including tetragonal ZrO 2 . The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.
1. A glass-ceramic, comprising:
a first crystal phase including (Mg x Zn 1-x )Al 2 O 4 where x is less than 1; and
a second crystal phase including tetragonal ZrO 2 ,
wherein the glass-ceramic is transparent in the visible range.
2. The glass-ceramic of claim 1 , further comprising at least one of Li 2 O and Na 2 O.
3. The glass-ceramic of claim 1 , further comprising Li 2 O and Na 2 O.
4. The glass-ceramic of claim 1 , wherein x is greater than 0.
5. The glass-ceramic of claim 1 , further comprising from greater than or equal to 35 mol % to less than or equal to 70 mol % SiO 2 .
6. The glass-ceramic of claim 1 , further comprising:
35 mol % to 60 mol % SiO 2 ;
greater than 13 mol % Al 2 O 3 ;
greater than 8 mol % ZnO;
0 mol % to 8 mol % MgO; and
greater than 0 mol % to 10 mol % ZrO 2 .
7. The glass ceramic of claim 6 , further comprising:
0 mol % to 6 mol % TiO 2 ;
0 mol % to 10 mol % Na 2 O;
0 mol % to 8 mol % Li 2 O;
0 mol % to 10 mol % HfO 2 ;
0 mol % to 0.1 mol % As 2 O 5 ; and
0 mol % to 0.3 mol % SnO 2 .
8. The glass-ceramic of claim 1 , wherein ZrO 2 +TiO 2 +HfO 2 ≥5 mol %.
9. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially free of TiO 2 .
10. The glass-ceramic of claim 1 , wherein the glass ceramic exhibits a crystallinity of at least 10 wt %.
11. The glass-ceramic of claim 1 , wherein the glass ceramic has a transmittance of at least 90% in the visible range.
12. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially colorless.
13. The glass-ceramic of claim 1 , wherein the first crystal phase has a crystallite size of less than 10 nm.
14. The glass-ceramic of claim 1 , further comprising a compressive stress region extending from a surface of the glass ceramic to a depth of compression.
15. The glass-ceramic of claim 1 , wherein the glass ceramic has a hardness of at least 9 GPa.
16. The glass-ceramic of claim 1 , wherein the glass ceramic has a Young's modulus of at least 98 GPa.
17. A consumer electronic product, comprising:
a housing comprising a front surface, a back surface and side surfaces;
electrical components at least partially within the housing, the electrical components comprising at least a controller, a memory, and a display, the display at or adjacent the front surface of the housing; and
a cover substrate disposed over the display,
wherein at least a portion of at least one of the housing or the cover substrate comprises the glass ceramic of claim 1 .
18. A method, comprising:
ceramming a precursor glass to form a glass ceramic that is transparent in the visible range,
wherein the glass ceramic comprises:
a first crystal phase including (Mg x Zn 1-x )Al 2 O 4 where x is less than 1; and
a second crystal phase including tetragonal ZrO 2 .
19. The method of claim 18 , further comprising forming nuclei in the precursor glass prior to the ceramming.
20. The method of claim 19 , wherein the forming nuclei comprises heat treating the precursor glass at a temperature of at least 700° C. for a time period of at least 1 hour.
21. The method of claim 18 , wherein the ceramming comprises heat treating the precursor glass at a temperature of at least 750° C. for a time period of at least 30 minutes.
22. The method of claim 18 , further comprising ion exchanging the glass ceramic.
23. The method of claim 22 , wherein the ion exchanging comprises contacting the glass ceramic with a mixed ion exchange bath.