Scratch resistant glass and method of making
Glass-based articles comprise stress profiles providing improved scratch resistance. A glass-based article comprises a lithium aluminosilicate composition and a molar ratio of potassium oxide (K 2 O) to sodium oxide (Na 2 O) averaged over a distance from the surface to a depth of 0.4 micrometers that is greater than or equal to 0 and less than or equal to 1.8. The article comprises sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article and a spike depth of layer that is greater than or equal to 4 micrometers and less than or equal to 8 micrometers. The article may comprise an average compressive stress of greater than or equal to 150 MPa over a depth from 15 micrometers to 40 micrometers.
1. A glass-based article comprising:
a lithium aluminosilicate composition, wherein at the center of the glass-based article, a molar ratio of sodium oxide (Na 2 O) to lithium oxide (Li 2 O) is less than or equal to 0.63;
sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article;
a spike depth of layer (DOL spike ) that is greater than or equal to 4 micrometers and less than or equal to 8 micrometers; and
a molar ratio of potassium oxide (K 2 O) to sodium oxide (Na 2 O) averaged over a distance from the surface to a depth of the glass-based article of 0.4 micrometers that is greater than or equal to 0 and less than or equal to 1.8.
2. The glass-based article of claim 1 , wherein the glass-based article has an average compressive stress (CS avg ) of greater than or equal to 115 MPa over a depth of the glass-based article from 15 micrometers to 40 micrometers.
3. The glass-based article of claim 1 , comprising a compressive stress at the knee (CS knee ) of greater than or equal to 115 MPa, wherein the DOL spike is greater than or equal to 4.4 micrometers.
4. The glass-based article of claim 1 , wherein a compressive stress at the knee (CS knee ) is greater than or equal to 120 MPa.
5. The glass-based article of claim 1 , wherein a depth of compression is greater than or equal to 150 micrometers.
6. The glass-based article of claim 1 , wherein at the center of the glass-based article, a base composition comprises: 9.39-25 mol % alumina (A 1 2 O 3 ), 0.1-20 mol % sodium oxide (Na 2 O), and up to 9.01 mol % boron oxide (B 2 O 3 ), and at least one alkaline earth metal oxide, wherein 15 mol %≤(R 2 O+R′O—Al 2 O 3 —ZrO 2 )—B 2 O 3 mol %, where R is Na and optionally one or more of Li, K, Rb, and Cs, and R′ is one or more of Mg, Ca, Sr, and Ba.
7. The glass-based article of claim 1 , comprising a Knoop scratch initiation threshold of greater than or equal to 5 N.
8. The glass-based article of claim 1 , wherein the glass-based article has a maximum compressive stress (CS max ) of greater than or equal to 500 MPa.
9. A consumer electronic product comprising:
a housing having a front surface, a back surface, and side surfaces;
electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and
a cover disposed over the display;
wherein at least a portion of at least one of the housing and the cover comprises the glass-based article of claim 1 .
10. A glass-based article comprising:
a lithium aluminosilicate composition, wherein at the center of the glass-based article, a molar ratio of sodium oxide (Na 2 O) to lithium oxide (Li 2 O) is less than or equal to 0.63;
sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article;
a spike depth of layer (DOL spike ) that is greater than or equal to 4 micrometers and less than or equal to 8 micrometers; and
an average compressive stress (CS avg ) of greater than or equal to 115 MPa over a depth of the glass-based article from 15 micrometers to 40 micrometers.
11. A consumer electronic product comprising:
a housing having a front surface, a back surface, and side surfaces;
electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and
a cover disposed over the display;
wherein at least a portion of at least one of the housing and the cover comprises the glass-based article of claim 10 .
12. A glass-based article comprising:
sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article;
an average compressive stress (CS avg ) of greater than or equal to 150 MPa over a depth of the glass-based article from 15 micrometers to 40 micrometers; and
a molar ratio of potassium oxide (K 2 O) to sodium oxide (Na 2 O) averaged over a distance from the surface to a depth of the glass-based article of 0.4 micrometers that is greater than or equal to 0 and less than or equal to 1.8.
13. The glass-based article of claim 12 , comprising a lithium aluminosilicate composition.
14. The glass-based article of claim 12 , wherein at the center of the glass-based article, a molar ratio of sodium oxide (Na 2 O) to lithium oxide (Li 2 O) is less than or equal to 0.63.
15. A consumer electronic product comprising:
a housing having a front surface, a back surface, and side surfaces;
electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and
a cover disposed over the display;
wherein at least a portion of at least one of the housing and the cover comprises the glass-based article of claim 12 .
16. A glass-based article comprising:
a thickness t;
sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article;
a depth of compression (DOC) that is greater than or equal to 0.20t;
a spike depth of layer (DOL spike ) that is greater than or equal to 4 micrometers and less than or equal to 8 micrometers;
a molar ratio of potassium oxide (K 2 O) to sodium oxide (Na 2 O) averaged over a distance from the surface to a depth of the glass-based article of 0.4 micrometers that is greater than or equal to 0 and less than or equal to 1.8; and
at the center of the glass-based article, a molar ratio of sodium oxide (Na 2 O) to lithium oxide (Li 2 O) is less than or equal to 0.63.
17. The glass-based article of claim 16 , wherein a depth of compression is greater than or equal to 160 micrometers.
18. The glass-based article of claim 16 , wherein at the center of the glass-based article, a base composition comprises: 9.39-25 mol % alumina (A 1 2 O 3 ), 0.1-20 mol % sodium oxide (Na 2 O), and up to 9.01 mol % boron oxide (B 2 O 3 ), and at least one alkaline earth metal oxide, wherein 15 mol %≤(R 2 O+R′O—Al 2 O 3 —ZrO 2 )—B 2 O 3 mol %, where R is Na and optionally one or more of Li, K, Rb, and Cs, and R′ is one or more of Mg, Ca, Sr, and Ba.
19. The glass-based article of claim 16 , comprising a Knoop scratch initiation threshold of greater than or equal to 5 N.
20. The glass-based article of claim 16 , wherein the glass-based article has a maximum compressive stress (CS max ) of greater than or equal to 500 MPa.
21. A consumer electronic product comprising:
a housing having a front surface, a back surface, and side surfaces;
electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and
a cover disposed over the display;
wherein at least a portion of at least one of the housing and the cover comprises the glass-based article of claim 16 .