Lithium disilicate-containing glass-ceramics some of which are self-glazing

• US 5,219,799 A
• Filed: 10/07/1991
• Issued: 06/15/1993
• Est. Priority Date: 10/07/1991
• Status: Expired due to Term

• Current Assignee: Ivoclar North America, Inc.
• Original Assignee: Corning Incorporated
• Inventors: Morrissey, Joseph W., Beall, George H., Pierson, Joseph E., Echeverria, Lina M.
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US07/772,217
• Time in Patent Office: 617 Days
• Field of Search: 501/5, 501/7, 501/63, 501/68, 501/69, 501/70, 501/71, 501/72
• US Class Current: 501/5
• CPC Class Codes: C03C 10/0009 containing silica as main constituent

Abstract

This invention relates to glass-ceramic articles containing lithium disilicate crystals as the predominant crystal phase and consisting essentially, in weight percent, 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, with a molar ratio (Na₂ O+K₂ O) (ZnO+Al₂ O₃) between 0.075-1.25, 65-80% SiO₂, and as a nucleating agent 1.5-7% P₂ O₅ and/or 0.0001-0.1% Pd. Glass-ceramics having certain compositions within those ranges are self-glazing.

Claims

1. A glass-ceramic article containing Li₂ O·

2SiO₂ as the predominant crystal phase 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, with a molar ratio (Na₂ O+K₂ O+CaO+SrO+BaO);

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

2. A glass-ceramic article according to claim 1 containing at least 2% ZnO and/or 2% K₂ O.

3. A glass-ceramic article according to claim 1 containing at least 1% CaO and/or 3% Al₂ O₃.

4. A glass-ceramic article according to claim 1 also containing 0.01-7% total of at least one member of the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Cr₂ O₃, CuO, Fe₂ O₃, MnO₂, NiO, and V₂ O₅.

5. A self-glazed glass-ceramic article containing Li₂ O·

2SiO₂ as the predominant crystal phase 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 0-7% K₂ O, 0-8% CaO, 0-6% SrO, and 0-6% BaO, 0-7% ZnO, 0-10% Al₂ O₃, 1.5-10% Al₂ O₃ +ZnO, with a molar ratio (K₂ O+CaO+SrO+BaO);

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

6. A self-glazed glass-ceramic article according to claim 5 also containing up to 3% ZrO₂.

7. A self-glazed glass-ceramic article according to claim 5 also containing 0.01-7% total of at least one member of the group consisting of CdS, cadmium sulfoselenide, CeO₂, Co₃ O₄, Fe₂ O₃, CuO, Cr₂ O₃, MnO₂, NiO, and V₂ O₅.