# US 11,401,202 B2 · β-spodumene glass-ceramics that are white, opalescent, or opaque, with low titanium content, and tin-fined > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,401,202 B2 - Document ID: US11401202B2 - Status: Granted - Kind: B2 - Application number: 16/632,740 - Filed: 2018-07-19 - Published: 2021-05-20 - Granted: 2022-08-02 - Earliest claimed: 2017-07-21 - Assignees: Eurokera - Applicants: Eurokera - Inventors: Philippe Lehuede; Marie Comte - Web page: https://patentgrep.com/patent/US11401202B2 ## CPC - C03C 10/0027: {containing SiO2, Al2O3, Li2O as main constituents} - A47J 27/002: {Construction of cooking-vessels; Methods or processes of manufacturing specially adapted for cooking-vessels} - A47J 36/027: {Cooking- or baking-vessels specially adapted for use in microwave ovens; Accessories therefor} - A47J 36/04: the materials being non-metallic - C03B 32/02: Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} - C03C 3/085: containing an oxide of a divalent metal - C03C 3/087: containing calcium oxide, e.g. common sheet or container glass - C03C 3/097: containing phosphorus, niobium or tantalum - C03C 10/0054: {containing PbO, SnO2, B2O3} - H05B 3/141: {Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds} - C03C 2204/00: Glasses, glazes or enamels with special properties - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - A47J: KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract The present application relates to glass-ceramics that are white, opalescent or opaque, of the lithium aluminosilicate (LAS) type, containing a solid solution of β-spodumene as the main crystalline phase. The application also provides articles that are constituted, at least in part, of said glass-ceramics, precursor glasses for said glass-ceramics, and a method of preparing said article. Said glass-ceramics have a composition that is free from arsenic oxide and antimony oxide, with the exception of inevitable traces, and that contains the following, expressed as percentages by weight of oxides: 60% to 70% of SiO2, 18% to 23% of Al2O3, 3.0% to 4.3% of Li2O, 0 to 2% of MgO, 1 to 4% of ZnO, 0 to 4% of BaO, 0 to 4% of SrO, 0 to 2% of CaO, 1.3% to 1.75% of TiO2, 1% to 2% of ZrO2, 0.05% to 0.6% of SnO2, 0 to 2% of Na2O, 0 to 2% of K2O, 0 to 2% of P2O5, 0 to 2% of B2O3, with Na2O+K2O+BaO+SrO+CaO≤6% and Na2O+K2O≤2%, and a maximum of 500 ppm of Fe2O3. ## Claims ### Claim 1 A glass-ceramic that is white, opalescent or opaque, of the lithium aluminosilicate (LAS) type, containing a solid solution of β-spodumene as the main crystalline phase, the composition of which, exempt of arsenic oxide and antimony oxide, with the exception of inevitable traces, comprises, expressed as percentages by weight of oxides: 60% to 70% of SiO2, 18% to 23% of Al2O3, 3.0% to 4.3% of Li2O, 0 to 2% of MgO, 1 to 4% of ZnO, 0 to 4% of BaO, 0 to 4% of SrO, 0 to 2% of CaO, 1.3% to 1.75% of TiO2, 1% to 2% of ZrO2, 0.05% to 0.6% of SnO2, 0 to 2% of Na2O, 0 to 2% of K2O, 0 to 2% of P2O5, 0 to 2% of B2O3, with Na2O+K2O+BaO+SrO+CaO≤6% and Na2O+K2O≤2%, and a maximum of 500 ppm of Fe2O3, wherein the glass-ceramic comprises an optical transmission (Y) greater than or equal to 0.1% for a 4 mm thick panel. ### Claim 2 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises ZrO2 at a content greater than or equal to 1.5% and less than or equal to 1.9%. ### Claim 3 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises 0.1 to 4% of BaO. ### Claim 4 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises Na2O: 0-1%, K2O:0-1%, with Na2O+K2O+BaO+SrO+CaO≤5% and Na2O+K2O≤1.5%. ### Claim 5 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises Na2O: 0-1%, K2O: 0-1%, with Na2O+K2O+BaO+SrO+CaO≤5% and Na2O+K2O≤1%. ### Claim 6 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises an Al2O3 content greater than 20%. ### Claim 7 (depends on 6) The glass-ceramic according to claim 6, the composition of which comprises a MgO content less than or equal to 1.2%. ### Claim 8 (depends on 1) The glass-ceramic according to claim 1, the composition of which comprises a BaO+SrO content less than or equal to 1.5% and a CaO content greater than or equal to 0.5%; the composition of which is free of SrO, with the exception of inevitable traces, and comprises a BaO content less than or equal to 1.5%. ### Claim 9 (depends on 6) The glass-ceramic according to claim 6, the composition of which is exempt, with the exception of inevitable traces, of P2O5 or B2O3. ### Claim 10 (depends on 1) The glass-ceramic according to claim 1, the composition of which contains an Al2O3 content less than or equal to 20%. ### Claim 11 (depends on 10) The glass-ceramic according to claim 10, the composition of which contains an MgO content greater than 1.2%. ### Claim 12 (depends on 10) The glass-ceramic according to claim 10, the composition of which contains: 0 to 1.5% of BaO, 0 to 1.5% of SrO, 0 to 1% of Na2O, 0 to 1% of K2O, <1% of P2O5, <1% of B2O3, with Na2O+K2O+BaO+SrO+CaO≤5% and Na2O+K2O≤1%. ### Claim 13 (depends on 1) An article that is constituted, at least in part, by the glass-ceramic according to claim 1, comprising a cooktop, a worktop, a cooking utensil, a microwave oven plate, or a support for heat treatment. ### Claim 14 (depends on 13) A method of preparing an article according to claim 13, the method comprising in succession: melting a charge of vitrifiable raw materials, followed by fining the resulting molten glass; cooling the resulting fined molten glass and simultaneously shaping it into the shape desired for the intended article; and applying ceramming heat treatment to the shaped glass, which heat treatment comprises a first step of nucleation and a second step of crystal growth; wherein said charge of vitrifiable raw materials has a composition making it possible to obtain the glass-ceramic; and wherein said ceramming heat treatment comprises a crystal growth second step that is performed at least in part at a temperature higher than 1000° C.