# US 11,247,935 B2 · Beta-quartz glass-ceramics with high zinc content > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,247,935 B2 - Document ID: US11247935B2 - Status: Granted - Kind: B2 - Application number: 16/620,302 - Filed: 2018-06-06 - Published: 2020-05-07 - Granted: 2022-02-15 - Earliest claimed: 2017-06-07 - Assignees: Eurokera - Applicants: Eurokera - Inventors: Marie Comte; Tiphaine Ogier - Web page: https://patentgrep.com/patent/US11247935B2 ## CPC - C03C 10/0027: {containing SiO2, Al2O3, Li2O as main constituents} - C03B 32/02: Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} - C03C 3/087: containing calcium oxide, e.g. common sheet or container glass - C03C 4/02: for coloured glass - C03C 10/0009: {containing silica as main constituent} - C03C 10/0036: {containing SiO2, Al2O3 and a divalent metal oxide as main constituents} - C03C 10/0054: {containing PbO, SnO2, B2O3} - 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 - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES ## Abstract The present application provides LAS type transparent glass-ceramics of β-quartz of composition containing a high content of zinc, articles constituted at least in part of said glass-ceramics, glasses precursors of said glass-ceramics (with a low viscosity at high temperature), and also a method of preparing said articles. Said glass-ceramics present a composition, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed as percentages by weight of oxides, containing: 64.5% to 66.5% of SiO2; 19.0% to 20.6% of Al2O3; 3.0% to 3.6% of Li2O; 0 to 1% of MgO; 1.7% to 3.4% of ZnO; 2% to 3% of BaO; 0 to 3% of SrO; 0 to 1% of CaO; 2% to 4% of TiO2; 1% to 2% of ZrO2; 0 to 1% of Na2O; 0 to 1% of K2O; with Na2O+K2O+BaO+SrO+CaO≤6%; optionally up to 2% of at least one fining agent comprising SnO2; and optionally up to 2% of at least one coloring agent. ## Claims ### Claim 1 A transparent glass-ceramic of lithium aluminosilicate containing a solid solution of β-quartz as a main crystalline phase, a composition of which, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed in percentages by weight of oxides, comprises: 64.5% to 66.5% of SiO2; 19.0% to 20.6% of Al2O3; 3.0% to 3.6% of Li2O; 0 to 1% of MgO; 1.7% to 3.4% of ZnO; 2% to 3% of BaO; 0 to 3% of SrO; 0 to 1% of CaO; 2% to 4% of TiO2; 1% to 2% of ZrO2; 0 to 1% of Na2O; 0 to 1% of K2O; greater than 0.02% to 0.1% of Cr2O3; with Na2O+K2O+BaO+SrO+CaO≤6% and 0.07%≤V2O5+Fe2O3+Cr2O3≤0.39%; and optionally up to 2% of at least one fining agent comprising SnO2. ### Claim 2 (depends on 1) The glass-ceramic according to claim 1, wherein the composition comprises 3.1% to 3.5% of Li2O. ### Claim 3 (depends on 1) The glass-ceramic according to claim 1, wherein the composition comprises 1.7% to 2.8% of ZnO. ### Claim 4 (depends on 1) The glass-ceramic according claim 1, wherein the composition comprises 0.01 to 1% of MgO. ### Claim 5 (depends on 1) The glass-ceramic according to claim 1, wherein the composition comprises 0.05% to 0.6% of SnO2. ### Claim 6 (depends on 1) The glass-ceramic according to claim 1, wherein the composition further comprises V2O5 as coloring agent, alone or mixed with at least one other coloring agent selected from CoO and Fe2O3. ### Claim 7 (depends on 1) The glass-ceramic according to claim 1, having a coefficient of thermal expansion CTE25-700° C. in the range +/−3·10−7K−1. ### Claim 8 (depends on 1) An article constituted at least in part of a glass-ceramic according to claim 1. ### Claim 9 (depends on 5) The glass-ceramic of claim 5, wherein the composition comprises 0.15 to 0.4% of SnO2. ### Claim 10 (depends on 1) The glass-ceramic according to claim 1, wherein the composition comprises: 0.005% to 0.2% of V2O5; 0.01% to 0.32% of Fe2O3; and 0% to 0.1% of CoO. ### Claim 11 (depends on 1) The glass-ceramic according to claim 1, wherein the composition comprises: 0.015% to 0.1% of V2O5; 0.07% to 0.25% of Fe2O3; and greater than 0.02% to 0.04% of Cr2O3.