Glass ceramics having low rhodium levels

Patent metadata

Field	Value
Publication number	US-9403715-B2
Application number	US-201414286307-A
Country	US
Kind code	B2
Filing date	May 23, 2014
Priority date	May 30, 2013
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A glass ceramic precursor glass and a glass ceramic having low levels of rhodium and a method of controlling the amount of rhodium in such glasses and glass ceramics. The precursor glass and glass ceramic contain from about 1 ppm to about 10 ppm and, in certain embodiments, from about 1 ppm to about 6 ppm rhodium. The method of controlling of reducing rhodium dissolution from a rhodium-containing material such as, for example, an alloy into a glass melt comprises controlling and/or lowering the partial pressure of oxygen at the rhodium-containing vessel/glass interface by imposing a high humidity condition around the external (non-glass-contact) surface of the rhodium-containing material. The lower concentration of rhodium minimizes its coloring effect on the white color of the glass ceramic.

First claim

The invention claimed is:

1. A lithia-alumina-silica glass ceramic, the glass ceramic having an opacity of at least 85% over a wavelength range of 400 to 700 nm and having CIELAB color space coordinates L*, a*, and b*, wherein L* is at least 92, b* is at least −0.3, and wherein the glass ceramic comprises from 1 ppm to about 10 ppm rhodium.

2. The glass ceramic of claim 1 , wherein the glass ceramic is white or black.

3. The glass ceramic of claim 1 , wherein the glass ceramic is transparent to radio waves ranging in frequency from about 3 kHz to about 300 GHz.

4. The glass ceramic of claim 1 , wherein the glass ceramic is ion exchangeable.

5. The glass ceramic of claim 4 , wherein the glass ceramic is ion exchanged and has a layer extending from a surface of the glass ceramic to a depth of layer, wherein the layer has a compressive stress of at least 300 MPa, and wherein the depth of layer is at least about 30 microns.

6. The glass ceramic of claim 1 , wherein L* is in a range from about 923 to about 94, and a* is in a range from about −0.10 to about −0.50.

7. The glass ceramic of claim 1 , wherein the glass ceramic comprises: from about 62 to about 75 mol % SiO 2 ; from about 10.5 to about 17 mol % Al 2 O 3 ; from about 5 to about 13 mol % Li 2 O; from 0 to about 4 mol % ZnO; from about 0 to about 8 mol % MgO; from about 2 to about 5 mol % TiO 2 ; from 0 to about 4 mol % B 2 O 3 ; from 0 to about 5 mol % Na 2 O; from 0 to about 4 mol % K 2 O; from 0 to about 2 mol % ZrO 2 ; from 0 to about 7 mol % P 2 O 5 ; from 0 to about 0.3 mol % Fe 2 O 3 ; from 0 to about 2 mol % MnOx, and from about 0.05 to about 0.2 mol % SnO 2 , at least one β-spodumene solid solution comprising at least about 70 wt % of the crystalline phases of the glass-ceramic, at least one titanium-containing crystalline phase having an acicular morphology and a rutile phase.

8. The glass ceramic of claim 1 , wherein the glass ceramic comprises from 1 ppm to about 6 ppm rhodium.

Assignees

• Corning Inc

Inventors

• Biswas Samir
• Fu Qiang
• Lineman David Myron
• Stewart Ronald Leroy

Classifications

• C03B5/16

  Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces · CPC title

• C03C2204/04

  Opaque glass, glaze or enamel · CPC title

• Y10T428/315

  Surface modified glass [e.g., tempered, strengthened, etc.] · CPC title

• C03C21/002

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

• C03C10/0027 Primary

  containing SiO2, Al2O3, Li2O as main constituents · CPC title