Ion exchangeable, opaque gahnite-spinel glass ceramics with high hardness and modulus
An opaque 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 includes at least one of tetragonal ZrO 2 , MgTa 2 O 6 , mullite, and cordierite. The glass ceramic has a Young's modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa. 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 at least one of tetragonal ZrO 2 , MgTa 2 O 6 , mullite, and cordierite;
wherein the glass-ceramic is opaque in the visible range, has a Young's modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa; and
wherein the glass ceramic further comprising:
35 mol % to 55 mol % SiO 2 ;
greater than or equal to 18 mol % Al 2 O 3 ;
greater than or equal to 5 mol % MgO; and
greater than or equal to 2 mol % P 2 O 5 .
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 , wherein x is greater than 0.
4. The glass ceramic of claim 1 , further comprising:
ZnO in an amount less than 14 mol % ZnO;
0 mol % to 5 mol % TiO 2 ;
0 mol % to 5 mol % Na 2 O;
0 mol % to 5 mol % Li 2 O;
0 mol % to 2 mol % BaO;
0 mol % to 4 mol % B 2 O 3 ;
0 mol % to 1 mol % CaO;
0 mol % to 3 mol % Eu 2 O 3 ;
0 mol % to 6 mol % Ta 2 O 5 ;
0 mol % to 5 mol % La 2 O 3 ;
0 mol % to 0.1 mol % As 2 O 5 ; and
0 mol % to 0.3 mol % SnO 2 .
5. The glass-ceramic of claim 1 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤6 mol %.
6. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially free of TiO 2 .
7. The glass-ceramic of claim 1 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤5.5 mol %, and the glass ceramic comprises at least one of:
La 2 O 3 ;
Ta 2 O 5 ; and
greater than or equal to 2 mol % Li 2 O.
8. The glass-ceramic of claim 1 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤5.1 mol %, and the glass ceramic comprises less than 2 mol % Li 2 O and is substantially free of La 2 O 3 and Ta 2 O 5 .
9. The glass-ceramic of claim 1 , wherein the glass ceramic exhibits a crystallinity of at least 35 wt %.
10. The glass-ceramic of claim 1 , wherein the glass ceramic has a Young's modulus of from greater than or equal to 100 GPa to less than or equal to 125 GPa.
11. The glass-ceramic of claim 1 , wherein the glass ceramic has a hardness of from greater than or equal to 8 GPa to less than or equal to 13 GPa.
12. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially colorless.
13. The glass-ceramic of claim 1 , wherein the second crystal phase comprises tetragonal ZrO 2 .
14. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially free of ZrO 2 and the second crystal phase comprises MgTa 2 O 6 .
15. The glass-ceramic of claim 1 , wherein the glass ceramic is substantially free of nucleating agents and the second crystal phase comprises mullite and cordierite.
16. 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.
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 the housing comprises the glass ceramic of claim 1 .
18. 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 the housing comprises the glass ceramic of claim 16 .
19. 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 comprising MgTa 2 O 6 ;
wherein the glass-ceramic is opaque in the visible range, has a Young's modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa;
wherein the glass ceramic is substantially free of ZrO 2 .
20. The glass-ceramic of claim 19 , further comprising at least one of Li 2 O and Na 2 O.
21. The glass-ceramic of claim 19 , wherein x is greater than 0.
22. The glass-ceramic of claim 19 , further comprising from greater than or equal to 35 mol % to less than or equal to 60 mol % SiO 2 .
23. The glass-ceramic of claim 19 , further comprising:
35 mol % to 55 mol % SiO 2 ;
greater than or equal to 18 mol % Al 2 O 3 ;
greater than or equal to 5 mol % MgO; and
greater than or equal to 2 mol % P 2 O 5 .
24. The glass ceramic of claim 23 , further comprising:
ZnO in an amount less than 14 mol % ZnO;
0 mol % to 5 mol % TiO 2 ;
0 mol % to 5 mol % Na 2 O;
0 mol % to 5 mol % Li 2 O;
0 mol % to 2 mol % BaO;
0 mol % to 4 mol % B 2 O 3 ;
0 mol % to 1 mol % CaO;
0 mol % to 3 mol % Eu 2 O 3 ;
0 mol % to 6 mol % Ta 2 O 5 ;
0 mol % to 5 mol % La 2 O 3 ;
0 mol % to 0.1 mol % As 2 O 5 ; and
0 mol % to 0.3 mol % SnO 2 .
25. The glass-ceramic of claim 19 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤6 mol %.
26. The glass-ceramic of claim 19 , wherein the glass ceramic is substantially free of TiO 2 .
27. The glass-ceramic of claim 19 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤5.5 mol %, and the glass ceramic comprises at least one of:
La 2 O 3 ; and
greater than or equal to 2 mol % Li 2 O.
28. The glass-ceramic of claim 19 , wherein ZrO 2 +TiO 2 +Eu 2 O 3 +Ta 2 O 5 +La 2 O 3 ≤5.1 mol %, and the glass ceramic comprises less than 2 mol % Li 2 O and is substantially free of La 2 O 3 .
29. The glass-ceramic of claim 19 , wherein the glass ceramic exhibits a crystallinity of at least 35 wt %.
30. The glass-ceramic of claim 19 , wherein the glass ceramic has a Young's modulus of from greater than or equal to 100 GPa to less than or equal to 125 GPa.
31. The glass-ceramic of claim 19 , wherein the glass ceramic has a hardness of from greater than or equal to 8 GPa to less than or equal to 13 GPa.
32. The glass-ceramic of claim 19 , wherein the glass ceramic is substantially colorless.
33. The glass-ceramic of claim 19 , wherein the glass ceramic is substantially free of nucleating agents.