Colored, textured glass-ceramic articles

• US 5,176,961 A
• Filed: 10/07/1991
• Issued: 01/05/1993
• Est. Priority Date: 10/07/1991
• Status: Expired due to Term

• Current Assignee: Ivoclar North America, Inc.
• Original Assignee: Corning Incorporated
• Inventors: Echeverria, Lina M., Crooker, David H.
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): Bahta, Abraham
• Application Number:
  US07/772,216
• Time in Patent Office: 456 Days
• Field of Search: 501/4, 501/7, 501/5, 501/3, 428/409, 428/428, 428/701, 428/702, 428/913.3
• US Class Current: 428/409
• CPC Class Codes: C03C 10/0009 containing silica as main constituent
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block

Abstract

This invention is directed to the production of glass-ceramic articles comprising an interior portion and a surface layer exhibiting a variegated color, textured surface appearance. In the most preferred embodiment lithium disilicate crystals constitute the predominant crystal phase in both the interior portion and in the surface layer.

Claims

1. A glass-ceramic article wherein lithium disilicate crystals constitute the predominant crystal phase comprising an interior portion and a surface layer wherein at least a portion of said surface layer exhibits a variegated color, textured appearance resulting from the presence of a colorant therein, said interior portion and said surface layer having the same base composition consisting essentially, expressed in terms of weight percent on the oxide basis, of 8-19% Li₂ O, 0-5% Na₂ O, 0-7% K₂ O, 0-8% Na₂ O+K₂ O, 0-10% CaO, 0-6% SrO, 0-6% BaO, 2-12% Na₂ O+K₂ O+CaO+SrO+BaO, 0-7% ZnO, 0-11% Al₂ O₃, 1.5-11% ZnO Al₂ O₃ O, with a molar ratio (Na₂ O+K₂ O+CaO+SrO+BaO):

(ZnO+Al₂ O₃) between 0.075-1.25, 65-80% SiO₂, and 1.5-7% P₂ O₅ and/or 0.0001-0.1% Pd as a nucleating agent and the same crystal phase(s).

2. A glass-ceramic article according to claim 1 wherein the colorant contained in said surface layer is present in an amount of about 0.01-7% by weight total and is selected from the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Cr₂ O₃, CuO, Fe₂ O₃, MnO₂, NiO, V₂ O₅, and mixtures thereof.

3. A glass-ceramic article according to claim 1 wherein said interior portion is also colored through the presence of a colorant therein in an amount of about 0.01-7%by weight total, said colorant being selected from the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Cr₂ O₃, CuO, Fe₂ O₃, MnO₂, NiO, V₂ O₅, and mixtures thereof.

4. A glass-ceramic article according to claim 1 which is self-glazed wherein said interior portion and said surface layer have essentially the same base composition consisting essentially, expressed in terms of weight percent on the oxide basis, of 9-18% Li₂ O, 2-10% total of at least one member of the group consisting of a 0-7% K₂ O, 0-8% CaO, 0-6% SrO, and 0-6% BaO, 0-7% ZnO, 0-10% Al₂ O₃, 1.5-10% ZnO+Al₂ O₃, with a molar ratio (K₂ O+CaO+SrO+BaO):

(ZnO+Al₂ O₃) between 0.1-0.8, 65-77% SiO₂, and as a nucleating agent 2-6% P₂ O₅.

5. A glass-ceramic article according to claim 4 wherein the colorant contained in said surface layer is present in an amount of about 0.01-7% by weight total and is selected from the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Cr₂ O₃, CuO, Fe₂ O₃, MnO₂, NiO, V₂ O₅, and mixtures thereof.

6. A glass-ceramic article according to claim 4 wherein said interior portion is also colored through the presence of a colorant therein in an amount of about 0.01-7% by weight total, said colorant being selected from the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Cr₂ O₃, CuO, Fe₂ O₃, MnO₂, NiO, V₂ O₅, and mixtures thereof.