Chemically strengthenable machinable glass-ceramics

Patent metadata

Field	Value
Publication number	US-11518707-B2
Application number	US-202016980572-A
Country	US
Kind code	B2
Filing date	Mar 18, 2020
Priority date	Apr 2, 2019
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A glass-ceramic comprising, in weight percent on an oxide basis, of 50 to 70% SiO 2 , 0 to 20% Al 2 O 3 , 12 to 23% MgO, 0 to 4% Li 2 O, 0 to 10% Na 2 O, 0 to 10% K 2 O, 0 to 5% ZrO 2 , and 2 to 12% F, wherein the predominant crystalline phase of said glass-ceramic is a trisilicic mica, a tetrasilicic mica, or a mica solid solution between trisilicic and tetrasilicic, and wherein the total of Na 2 O+Li 2 O is at least 2 wt. %; wherein the glass-ceramic can be ion-exchanged.

First claim

What is claimed is:

1. A glass-ceramic comprising:
a silicate glass phase; and
a crystalline phase predominantly consisting of a tetrasilicic mica,

wherein the glass-ceramic comprises, by weight percent on an oxide basis, 50 to 70% SiO 2 , 0 to 20% Al 2 O 3 , 12 to 23% MgO, 0 to 4% Li 2 O, 0 to 10% Na 2 O, 0 to 10% K 2 O, 0 to 5% ZrO 2 , and 2 to 12% F, wherein the total of Na 2 O+Li 2 O is at least 2 wt. %; and wherein the glass-ceramic is free of P 2 O 5 .

2. The glass-ceramic of claim 1 , wherein the glass-ceramic can be ion-exchanged.

3. The glass-ceramic of claim 1 , further comprising, by weight percent on an oxide basis, 60 to 70% SiO 2 , 0 to 2% Al 2 O 3 , 15 to 20% MgO, 2 to 10% Na 2 O, 0 to 3% Li 2 O, and 3 to 7% F, wherein the glass-ceramic can be ion-exchanged.

4. The glass-ceramic of claim 1 , having an average grain size of 20 microns or less.

5. The glass-ceramic of claim 1 , having an average grain size of 2 microns or less.

6. The glass-ceramic of claim 1 , comprising from about 30 wt. % to about 80 wt. % crystalline phase.

7. The glass-ceramic of claim 1 , having a density of about 2 g/cc to about 3 g/cc.

8. The glass-ceramic of claim 1 , having a Young's modulus of about 60 GPa to about 70 Gpa.

9. The glass-ceramic of claim 1 , having a Shear modulus of about 18 GPa to about 30 Gpa.

10. The glass-ceramic of claim 1 , having a fracture toughness of about 1 MPa·m 0.5 to about 5.0 MPa·m 0.5 .

11. The glass-ceramic of claim 1 , having a Vickers hardness of about 100 kgf to about 400 kgf.

12. The glass-ceramic of claim 1 , having a Knoop hardness of about 150 kg/mm 2 to about 300 kg/mm 2 .

13. The glass-ceramic of claim 1 , having a Moh's hardness of about 3 to about 7.

14. The glass-ceramic of claim 1 , having an opacity of ≥80% for a 1 mm thickness over the wavelength range from about 380 nm to about 740 nm.

15. The glass-ceramic of claim 1 , having a Poisson's ratio of about 0.2 to about 0.3.

16. The glass-ceramic of claim 1 , having a mechanical strength greater than 100 MPa.

17. The glass-ceramic of claim 1 , having a porosity of 0% to 10%.

18. The glass-ceramic of claim 1 , wherein the glass-ceramic is machinable.

19. The glass-ceramic of claim 1 , which is ion-exchanged.

20. The ion-exchanged glass-ceramic of claim 19 , having a depth of ion penetration of about 3% to about 23% of thickness.

21. An article comprising the glass-ceramic of claim 1 .

Assignees

• Corning Inc

Inventors

• Beall George Halsey
• Finkeldey John Philip
• Smith Charlene Marie

Classifications

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• C03B25/02

  in a discontinuous way · CPC title

• C03C10/0045 Primary

  containing SiO2, Al2O3 and MgO as main constituents · CPC title

• C03C3/112

  containing fluorine · CPC title

• C03C3/078 Primary

  containing an oxide of a divalent metal, e.g. an oxide of zinc · CPC title