GLASS BALL

• US 20200131086A1
• Filed: 12/30/2019
• Published: 04/30/2020
• Est. Priority Date: 07/04/2017
• Status: Active Grant

• Current Assignee: AGC, Inc.
• Original Assignee: AGC, Inc.
• Inventors: KOIKE, Akio, KATSUTA, Makoto, MURAYAMA, Suguru, IMAKITA, Kenji
• Granted Patent: US 11,028,015 B2
• Time in Patent Office: Days
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/32 Thermal properties
• CPC Class Codes: C03C 12/00 Powdered glass C03C8/02 takes precedence; Bead compositions
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/062 with less than 40% silica by weight
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/083 containing aluminium oxide or an iron compound
• CPC Class Codes: C03C 3/085 containing an oxide of a divalent metal
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/095 containing rare earths
• CPC Class Codes: F16C 2202/04 Hardness
• CPC Class Codes: F16C 2202/22 Coefficient of expansion
• CPC Class Codes: F16C 2202/32 Conductivity
• CPC Class Codes: F16C 2206/42 based on ceramic oxides
• CPC Class Codes: F16C 2240/70 Diameters; Radii
• CPC Class Codes: F16C 2300/22 High-speed rotation
• CPC Class Codes: F16C 2362/52 Compressors of refrigerators, e.g. air-conditioners in general F25
• CPC Class Codes: F16C 33/32 Balls

Abstract

A glass ball has a density of 2.3 to 3.2 g/cm³, a Young'"'"'s modulus of 60 to 150 GPa, and an average coefficient of thermal expansion at 50 to 350° C. being 40×10⁻⁷ to 120×10⁻⁷/° C. The glass ball is formed of a glass material including, as represented by mole percentage based on oxides, 30 to 75 mol % of SiO₂, 2 to 30 mol % of Al₂O₃, and 5 to 25 mol % of R₂O, where R is at least one kind selected from Li, Na and K. The glass ball includes a compressive stress layer in a surface thereof.

Claims

1. A glass ball, having:

a density of 2.3 to 3.2 g/cm³;

a Young'"'"'s modulus of 60 to 150 GPa; and

an average coefficient of thermal expansion at 50 to 350°

C. being 40×

10<sup>−

7</sup> to 120×

10<sup>−

7</sup>/°

C.,

the glass ball being formed of a glass material comprising, as represented by mole percentage based on oxides, 30 to 75 mol % of SiO₂, 2 to 30 mol % of Al₂O₃, and 5 to 25 mol % of R₂O, wherein R is at least one kind selected from Li, Na and K, and

the glass ball comprising a compressive stress layer in a surface thereof.

2. The glass ball according to claim 1, wherein the compressive stress layer has a depth (DOL) of 8 to 500 μ

m.

3. The glass ball according to claim 1, wherein the glass material is a Li-based glass comprising, as represented by mole percentage based on oxides, 50 to 75 mol % of SiO₂, 4 to 20 mol % of Al₂O₃, 1 to 15 mol % of Li₂O, 5 to 25 mol % of R₂O, and 0 to 15 mol % of MgO, wherein R is at least one kind selected from Li, Na and K, and SiO₂+Al₂O₃+R₂O+MgO is 92 mol % or higher.

4. The glass ball according to claim 1, wherein the glass material is a Y₂O₃-based glass comprising, as represented by mole percentage based on oxides, 30 to 70 mol % of SiO₂, 4 to 30 mol % of Al₂O₃, 5 to 20 mol % of Li₂O, 5 to 25 mol % of R₂O, 1 to 25 mol % of MgO, and 1 to 20 mol % of Y₂O₃, wherein R is at least one kind selected from Li, Na and K.

5. The glass ball according to claim 1, having a surface compressive stress value (CS₀) of 200 to 1,500 MPa.

6. The glass ball according to claim 1, having a Vickers hardness (Hvct) of 6.0 GPa or more.

7. The glass ball according to claim 1, having a diameter of 0.5 to 100 mm.