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US-12623957-B2 - Glass-ceramic articles with increased resistance to fracture and methods for making the same

US12623957B2US 12623957 B2US12623957 B2US 12623957B2US-12623957-B2

Abstract

A glass-ceramic article having one or more crystalline phases; a residual glass phase; a compressive stress layer extending from a first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m 2 ; a fracture toughness greater than 1.0 MPa√m; and a haze less than 0.2.

Inventors

  • Carol Ann Click
  • Andrew Peter Kittleson
  • Rohit Rai
  • John Robert Saltzer, JR.
  • Charlene Marie Smith
  • Matthew Daniel Trosa
  • Matthew Artus Tuggle
  • James Clark Walck, JR.
  • Alana Marie Whittier
  • Zheming Zheng
  • Indrajit Dutta
  • James Howard Edmonston
  • Michael S Fischer
  • Qiang Fu
  • Ozgur Gulbiten
  • Jill Marie Hall
  • Mathieu Gerard Jacques Hubert
  • Dhananjay Joshi

Assignees

  • CORNING INCORPORATED

Dates

Publication Date
20260512
Application Date
20190716

Claims (18)

  1. 1 . A method of forming a glass-ceramic article, the method comprising: heating a glass composition to a nucleation temperature (T N ) to create a nucleated crystallizable glass composition; heating the nucleated crystallizable glass composition to a crystallization temperature (T c ), wherein the crystallization temperature is in a range from 720° C. to 800° C.; and maintaining the crystallization temperature for a predetermined period of time (t c ) to produce the glass-ceramic article, wherein the glass-ceramic article comprises: a residual glass phase that is less than or equal to 50 wt % of the glass-ceramic article; a fracture toughness greater than 1.0 MPa√m; and a haze less than 0.2, wherein a composition of the glass-ceramic article, based on 100 mol % of the glass-ceramic article, comprises: greater than or equal to 1.7 mol % ZrO 2 ; from 65 mol % to 72 mol % SiO 2 ; from 0 mol % to 6 mol % Al 2 O 3 ; from 20 mol % to 32 mol % Li 2 O; from 0 mol % to 2 mol % B 2 O 3 ; from 0 mol % to 2 mol % Na 2 O; and from 0 mol % to 2 mol % K 2 O, wherein the glass-ceramic article comprises a molar ratio Li 2 O (mol %)/R 2 O (mol %) from greater than or equal to 0.85 to less than or equal to 1.00, where R 2 O is a total amount of Li 2 O, Na 2 O, and K 2 O.
  2. 2 . The method of claim 1 , further comprising: maintaining the nucleation temperature for a predetermined period of time to produce the nucleated crystallizable glass composition, wherein the period of time for maintaining the nucleation temperature is in a range from 1 minute to 6 hours.
  3. 3 . The method of claim 1 , further comprising: heating the nucleated crystallizable glass composition to an intermediate temperature, wherein the intermediate temperature is greater than the nucleation temperature and less than the crystallization temperature, and maintaining the intermediate temperature for a predetermined period of time; and heating the nucleated crystallizable glass composition from the intermediate temperature to the crystallization temperature.
  4. 4 . The method of claim 3 , wherein a heating rate for heating the nucleated crystallizable glass composition from the nucleation temperature to the intermediate temperature is different than the heating rate for heating the nucleated crystallizable glass composition from the intermediate temperature to the crystallization temperature.
  5. 5 . The method of claim 1 , further comprising: subjecting the glass-ceramic article to an ion-exchange treatment to create a compressive stress layer extending from a first surface of the glass-ceramic article to a depth of compression (DOC), wherein after the ion-exchange treatment the glass-ceramic article has a maximum central tension greater than 70 MPa and a stored tensile energy greater than 22 J/m 2 .
  6. 6 . The method of claim 1 , wherein the nucleation temperature is in a range from 550° C. to 650° C., and wherein the heating to the nucleation temperature comprises heating from room temperature to the nucleation temperature at a heating rate in a range from 0.01° C./min to 50° C./min.
  7. 7 . The method of claim 1 , and wherein the predetermined period of time for maintaining the crystallization temperature is in a range from 1 minute to 4 hours.
  8. 8 . The method of claim 1 , wherein the heating to the crystallization temperature comprises heating from the nucleation temperature to the crystallization temperature at a heating rate in a range from 0.01° C./min to 50° C./min.
  9. 9 . The method of claim 1 , further comprising: in a first cooling stage, cooling the glass-ceramic article from the crystallization temperature to a first temperature at a first cooling rate; and in a second cooling stage, cooling the glass-ceramic article from the first temperature to a second temperature at a second cooling rate, wherein the first cooling rate is slower than the second cooling rate.
  10. 10 . The method of claim 1 , further comprising: in a first cooling stage, cooling the glass-ceramic article from the crystallization temperature to a first temperature at a first cooling rate; in an intermediate cooling stage, cooling the glass-ceramic article from the first temperature to a second temperature at a second cooling rate; in a second cooling stage, cooling the glass-ceramic article from the second temperature to a third temperature at a third cooling rate, wherein (i) the first cooling rate is slower than the second cooling rate and the third cooling rate and (ii) the second cooling rate is slower than the third cooling rate.
  11. 11 . The method of claim 1 , wherein the glass-ceramic article comprises from greater than or equal to 1.7 mol % to less than or equal to 4.5 mol % ZrO 2 .
  12. 12 . The method of claim 1 , wherein the glass-ceramic article comprises greater than or equal to 24 mol % Li 2 O.
  13. 13 . The method of claim 1 , wherein the glass-ceramic article comprises from greater than or equal to 24 mol % to less than or equal to 32 mol % Li 2 O.
  14. 14 . The method of claim 1 , wherein the molar ratio Li 2 O (mol %)/R 2 O (mol %) is greater than or equal to 0.95.
  15. 15 . The method of claim 1 , wherein the molar ratio Li 2 O (mol %)/R 2 O (mol %) is from greater than or equal to 0.95 to less than or equal to 0.99.
  16. 16 . The method of claim 1 , wherein the glass-ceramic article comprises from 0.7 mol % to 2.2 mol % P 2 O 5 .
  17. 17 . The method of claim 1 , wherein the glass-ceramic article comprises a Young's modulus greater than 95 GPa.
  18. 18 . The method of claim 1 , wherein the glass-ceramic article comprises a crystal phase comprising lithium disilicate, petalite, or combinations thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/698,532 filed on Jul. 16, 2018 and U.S. Provisional Application Ser. No. 62/736,682 filed on Sep. 26, 2018, the contents of each of which are relied upon and incorporated herein by reference in their entireties. FIELD The disclosure relates to glass-ceramic articles with increased resistance to fracture, and more particularly to ion-exchanged glass-ceramic articles with high fracture toughness and stored tensile energy and low haze, and ceramming schedules for making the same. BACKGROUND Glass-ceramic articles can be used as cover substrates and housings for mobile electronic devices. In some instances, glass-ceramic articles can have better mechanical properties than glass in terms of mechanical properties such as resistance to crack penetration and drop performance. Resistance to crack penetration and drop performance are important mechanical properties for cover substrates and housings for mobile electronic devices and there is a need to increase these mechanical properties in glass-ceramic articles. When glass-ceramic articles are used as cover substrates, where transparency is important, it is desirable for the glass-ceramic to have suitable optical characteristics. The optical characteristics can be achieved through the heating treatments that convert a glass into a glass-ceramic. There is a need to improve the heating treatments to achieve desirable optical characteristics in glass-ceramic articles. SUMMARY In a first aspect, a glass-ceramic article comprises: a first surface; a second surface opposing the first surface; one or more crystalline phases; a residual glass phase; a compressive stress layer extending from the first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m2; a fracture toughness greater than 1.0 MPa√m, wherein the fracture toughness is measured for a glass-ceramic having a composition and phase assemblage equivalent to the composition and phase assemblage at a center of the glass-ceramic article; and a haze less than 0.2. In a second aspect, a glass-ceramic article comprises: a first surface; a second surface opposing the first surface; one or more crystalline phases; a residual glass phase; a compressive stress layer extending from the first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m2; Young's modulus greater than 95 GPa, wherein the Young's modulus is measured for a glass-ceramic having a composition and phase assemblage equivalent to the composition and phase assemblage at a center of the glass-ceramic article; and a haze less than 0.2. In a third aspect, a glass-ceramic article comprises: a first surface; a second surface opposing the first surface; one or more crystalline phases; a residual glass phase; a compressive stress layer extending from the first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m2; ZrO2 in a range from 1.7 mol % to 4.5 mol %; and a ratio of LiO2 (mol %)/R2O (mol %) is greater than 0.85, wherein R2O is a sum of alkali metal oxides. In a fourth aspect, a method of forming a glass-ceramic article, the method comprises: heating a glass composition to a nucleation temperature to create a nucleated crystallizable glass composition; heating the nucleated crystallizable glass composition to a crystallization temperature; and maintaining the crystallization temperature for a predetermined period of time to produce the glass-ceramic article, wherein the glass-ceramic article comprises: a fracture toughness greater than 1.0 MPa√m; and a haze less than 0.2. In a fifth aspect, a method of forming a glass-ceramic article, the method comprises: heating a glass composition to a nucleation temperature (TN); maintaining the nucleation temperature for a first predetermined period of time (tN) to produce a nucleated crystallizable glass composition; heating the nucleated crystallizable glass composition to a crystallization temperature (TC); and maintaining the crystallization temperature for a second predetermined period of time (tC) to produce the glass-ceramic article, wherein (103−0.260TN+0.000203(TN)2−7.96tN+0.1532(tN)2−0.019TC−0.000008(TC)2−10.03tC+0.00597TN*tN+0.00463tN*TC+0.01342TC*tC)<0.2. In a sixth aspect, a method for controlling the haze of a glass-ceramic article comprises: selecting a nucleation temperature (TN), a first predetermined period of time (tN), a crystallization temperature (TC), and a second predetermined period of time (tC) so that (103−0.260TN+0.000203(TN)2−7.96tN+0.1532(tN)2−0.019TC−0.000008(TC)2−10.03tC+0.00597TN*tN+0.00463tN*TC+0.01342TC*tC)<0.2. Additional features and advantages will be set forth in the detailed description which follows,