# US 2021/0276913 A1 · Method for forming glass-ceramic articles and glass-ceramic articles formed therefrom > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0276913 A1 - Document ID: US20210276913A1 - Status: Published application - Kind: A1 - Application number: 17/049,600 - Filed: 2019-04-18 - Published: 2021-09-09 - Earliest claimed: 2018-04-24 - Applicants: Corning Incorporated - Inventors: Indrajit Dutta; Mathieu Gerard Jacques Hubert; Timothy James Kiczenski; Marion Novitovic-Dunn - Web page: https://patentgrep.com/patent/US20210276913A1 ## CPC - C03B 32/02: Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} - C03C 10/0027: {containing SiO2, Al2O3, Li2O as main constituents} - C03C 4/02: for coloured glass - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - 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 ## Abstract A process for making a glass-ceramic article includes annealing an as-formed glass article formed from a glass-ceramic composition at a first temperature for a duration sufficient to nucleate a plurality of nuclei within a vitreous matrix of the as-formed glass article and forming a post-nucleation glass article. The process also includes annealing the post-nucleation glass article at a second temperature for a duration sufficient to grow crystalline grains within the vitreous matrix of the post-nucleation glass article and forming a glass-ceramic article. The first temperature is less than a glass transition temperature for the glass-ceramic composition and the second temperature is greater than the glass transition temperature for the glass-ceramic composition. ## Claims ### Claim 1 A method for making a glass-ceramic article from a glass-ceramic composition, the process comprising: annealing an as-formed glass article comprising a glass-ceramic composition at a first temperature for a duration sufficient to nucleate a plurality of nuclei within a vitreous matrix of the glass-ceramic composition and forming a post-nucleation glass article; and annealing the post-nucleation glass article at a second temperature for a duration sufficient to grow crystalline grains within the vitreous matrix of the post-nucleation glass article and forming a glass-ceramic article; wherein the first temperature is less than a glass transition temperature for the glass-ceramic composition and the second temperature is greater than the glass transition temperature for the glass-ceramic composition. ### Claim 2 (depends on 1) The method of claim 1, wherein the first temperature is at least 25° C. less than the glass transition temperature for the glass-ceramic composition. ### Claim 3 (depends on 2) The method of claim 2, wherein the first temperature is at least 50° C. less than the glass transition temperature for the glass-ceramic composition. ### Claim 4 (depends on 3) The method of claim 3, wherein the first temperature is at least 100° C. less than the glass transition temperature for the glass-ceramic composition. ### Claim 5 (depends on 1) The method of claim 1, wherein a viscosity of the glass-ceramic composition is equal to or greater than 1013 poise at the glass transition temperature. ### Claim 6 (depends on 1) The method of any of claim 1, wherein the glass-ceramic composition comprises a chemical composition comprising Li2O, Al2O3, SiO2, and Fe2O3, and has a glass transition temperature between about 590° C. and about 610° C. ### Claim 7 (depends on 6) The method of claim 6, wherein the first temperature is less than 550° C. ### Claim 8 (depends on 7) The method of claim 7, wherein the first temperature is less than 500° C. ### Claim 9 (depends on 8) The method of claim 8, wherein the first temperature is less than 450° C. ### Claim 10 (depends on 1) The method of claim 1, wherein the as-formed glass article is annealed at the first temperature for less than 8 hours. ### Claim 11 (depends on 10) The method of claim 10, wherein the as-formed glass article is annealed at the first temperature for less than 6 hours. ### Claim 12 (depends on 1) The method of claim 1, wherein a viscosity of the as-formed glass article at the first temperature is equal to or greater than 1.0×1013 poise and the viscosity of the post-nucleation glass article at the second temperature is less than 1.0×1013 poise. ### Claim 13 (depends on 12) The method of claim 12, wherein the viscosity of the as-formed glass article at the first temperature is greater than or equal to 5.0×1013 poise. ### Claim 14 (depends on 13) The method of claim 13, wherein the viscosity of the as-formed glass article at the first temperature is greater than or equal to 1.0×1014 poise. ### Claim 15 A glass-ceramic article prepared by a process comprising: annealing an as-formed glass article formed from a glass-ceramic composition comprising a chemical composition comprising Li2O, Al2O3, SiO2, and Fe2O3 at a first temperature such that a plurality of nuclei nucleate within a vitreous matrix of the as-formed glass article and form a post-nucleation glass article; annealing the post-nucleation glass article at a second temperature such that crystalline grains grow within the vitreous matrix of the post-nucleation glass article and form the glass-ceramic glass article; wherein the first temperature is less than a glass transition temperature for the glass-ceramic composition and the second temperature is greater than the glass transition temperature for the glass-ceramic composition. ### Claim 16 A method for making a glass-ceramic article from a glass-ceramic composition, the process comprising: annealing an as-formed glass article comprising a glass-ceramic composition at a first temperature for a duration sufficient to nucleate a plurality of nuclei within a vitreous matrix of the glass-ceramic composition and forming a post-nucleation glass article; and annealing the post-nucleation glass article at a second temperature for a duration sufficient to grow crystalline grains within the vitreous matrix of the post-nucleation glass article and forming a glass-ceramic article; wherein the first temperature is less than a glass transition temperature for the glass-ceramic composition and the second temperature is greater than the glass transition temperature for the glass-ceramic composition; wherein the glass-ceramic composition comprises a chemical composition comprising Li2O, Al2O3, SiO2, and Fe2O3, and has a glass transition temperature between about 590° C. and about 610° C.; wherein a viscosity of the as-formed glass article at the first temperature is equal to or greater than 1.0×1013 poise and the viscosity of the post-nucleation glass article at the second temperature is less than 1.0×1013 poise. ### Claim 17 (depends on 16) The method of claim 16, wherein the first temperature is at least 25° C. less than the glass transition temperature for the glass-ceramic composition. ### Claim 18 (depends on 17) The method of claim 17, wherein the as-formed glass article is annealed at the first temperature for less than 8 hours. ### Claim 19 (depends on 18) The method of claim 18, wherein the first temperature is at least 100° C. less than the glass transition temperature for the glass-ceramic composition. ### Claim 20 (depends on 19) The method of claim 19, wherein the first temperature is less than 550° C.