Abstract: A method for ceramming a glass article to a glass-ceramic includes placing a glass article into a heating apparatus, and heating the glass article to a first hold temperature at a first predetermined heating rate. The glass article is held at the first hold temperature for a first predetermined duration. The viscosity of the glass article is maintained within log viscosity ±1.0 poise during the first predetermined duration. The glass article is then heated from the first hold temperature to a second hold temperature at a second predetermined heating rate. The glass article is held at the second hold temperature for a second duration. A density of the glass article is monitored from the heating of the glass article from the first hold temperature through the second duration, and the second duration is ended when an absolute value of a density rate of change of the glass article is less than or equal to 0.10 (g/cm3)/min.

Abstract: A glass-ceramic article comprises: a center-volume composition comprising (on an oxide basis): 55-75 mol % SiO2; 0.2-10 mol % Al2O3; 0-5 mol % B2O3; 15-30 mol % Li2O; 0-2 mol % Na2O; 0-2 mol % K2O; 0-5 mol % MgO; 0-2 mol % ZnO; 0.2-3.0 mol % P2O5; 0.1-10 mol % ZrO2; 0-4 mol % TiO2; and 0-1.0 mol % SnO2. Lithium disilicate and either ?-spodumene or ?-quartz are the two predominant crystalline phases (by weight) of the glass-ceramic article. The glass-ceramic article further comprises tetragonal ZrO2 as a crystalline phase. The composition of the glass-ceramic article from a primary surface into a thickness of the glass-ceramic article can comprise over 10 mol % Na2O (on an oxide basis), with the mole percentage of Na2O decreasing from the primary surface towards the center-volume. The glass-ceramic article exhibits a ring-on-ring load-to-failure of at least 120 kgf, when the thickness of the glass-ceramic article is 0.3 mm to 2.0 mm.

Abstract: A method of minimizing the formation of a rhodium-platinum defect in a glass or glass ceramic material or in the melt thereof is provided. The method includes providing a vessel made of a platinum-rhodium alloy for use in a manufacturing process for obtaining the material, and an interface between the vessel and the melt is present. The method can include providing sufficient partial pressures of hydrogen outside and inside the vessel for controlling the partial pressure of oxygen in a region of the melt adjacent to the interface. A method of minimizing the formation of, or counteracting the impact of, a localized thermal, electrical, or composition cell in the melt during a manufacturing process is also provided. The method can include adding a multivalent compound to the melt, adding a mixer to the finer tube, adding a mixing step to the manufacturing process, or amplifying the mixing.

Abstract: A glass-ceramic article comprises: a center-volume composition comprising (on an oxide basis): 55-75 mol % SiO2; 0.2-10 mol % Al2O3; 0-5 mol % B2O3; 15-30 mol % Li2O; 0-2 mol % Na2O; 0-2 mol % K2O; 0-5 mol % MgO; 0-2 mol % ZnO; 0.2-3.0 mol % P2O5; 0.1-10 mol % ZrO2; 0-4 mol % TiO2; and 0-1.0 mol % SnO2. Lithium disilicate and either ?-spodumene or ?-quartz are the two predominant crystalline phases (by weight) of the glass-ceramic article. The glass-ceramic article further comprises tetragonal ZrO2 as a crystalline phase. The composition of the glass-ceramic article from a primary surface into a thickness of the glass-ceramic article can comprise over 10 mol % Na2O (on an oxide basis), with the mole percentage of Na2O decreasing from the primary surface towards the center-volume. The glass-ceramic article exhibits a ring-on-ring load-to-failure of at least 120 kgf, when the thickness of the glass-ceramic article is 0.3 mm to 2.0 mm.

Abstract: A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (?m)<(3.65×10?9/?m×diagonal2) where diagonal is a diagonal measurement of the glass ceramic article in ?m, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t+0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10(2-0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Abstract: A glass-ceramic article having greater than or equal to 65.00 wt. % and less than or equal to 80.00 wt. % SiO2, greater than 4.00 wt. % and less than or equal to 12.00 wt. % Al2O3, greater than or equal to 0.10 wt. % and less than or equal to 3.5 wt. % P2O5, greater than or equal to 8.00 wt. % and less than or equal to 17.00 wt. % Li2O, greater than or equal to 4.00 wt. % and less than or equal to 15.00 wt. % ZrO2, and greater than or equal to 0.05 wt. % and less than or equal to 4.00 wt. % CaO.

Abstract: A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (?m)<(3.65×10?9/?m×diagonal2) where diagonal is a diagonal measurement of the glass ceramic article in ?m, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t+0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10(2?0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Abstract: A black ?-spodumene lithium disilicate glass ceramic is provided. The glass ceramic includes at least one of magnetite, ?-quartz, cristobalite, and lithium phosphate as a minor crystal phase. The glass ceramic is characterized by the color coordinates: L*: 15.0 to 35.0, a*: ?3.0 to 3.0, and b*: ?5.0 to 5.0. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

Abstract: A glass-ceramic article comprises: a center-volume composition comprising (on an oxide basis): 55-75 mol % SiO2; 0.2-10 mol % Al2O3; 0-5 mol % B2O3; 15-30 mol % Li2O; 0-2 mol % Na2O; 0-2 mol % K2O; 0-5 mol % MgO; 0-2 mol % ZnO; 0.2-3.0 mol % P2O5; 0.1-10 mol % ZrO2; 0-4 mol % TiO2; and 0-1.0 mol % SnO2. Lithium disilicate and either ?-spodumene or ?-quartz are the two predominant crystalline phases (by weight) of the glass-ceramic article. The glass-ceramic article further comprises tetragonal ZrO2 as a crystalline phase. The composition of the glass-ceramic article from a primary surface into a thickness of the glass-ceramic article can comprise over 10 mol % Na2O (on an oxide basis), with the mole percentage of Na2O decreasing from the primary surface towards the center-volume. The glass-ceramic article exhibits a ring-on-ring load-to-failure of at least 120 kgf, when the thickness of the glass-ceramic article is 0.3 mm to 2.0 mm.

Abstract: A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (?m)<(3.65×10?9/?m×diagonal2) where diagonal is a diagonal measurement of the glass ceramic article in ?m, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t+0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10(2?0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Abstract: A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (?m)<(3.65×10?9/?m×diagonal2) where diagonal is a diagonal measurement of the glass ceramic article in ?m, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t +0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10(2-0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Abstract: A method for forming glass ceramic articles includes heating a stack of glass sheets to a nucleation temperature to create a nucleated crystallizable stack of sheets; heating the nucleated crystallizable stack of glass sheets to a crystallization temperature; and maintaining the crystallization temperature for a predetermined period of time to produce the glass-ceramic articles. The stack of glass sheets has a mass index of less than or equal to 35.

Abstract: A black ?-spodumene lithium disilicate glass ceramic is provided. The glass ceramic includes at least one of magnetite, ?-quartz, cristobalite, and lithium phosphate as a minor crystal phase. The glass ceramic is characterized by the color coordinates: L*: 15.0 to 35.0, a*: ?3.0 to 3.0, and b*: ?5.0 to 5.0. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

Abstract: A glass-ceramic article having one or more crystalline phases; a residual glass phase; a compressive stress layer extending from a first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m2; a fracture toughness greater than 1.0 MPa?m; and a haze less than 0.2.

Abstract: A glass ceramic article including a lithium disilicate crystalline phase, a petalite crystalline phased, and a residual glass phase. The glass ceramic article has a warp (?m)<(3.65×10?6/?m×diagonal2) where diagonal is a diagonal measurement of the glass ceramic article in ?m, a stress of less than 30 nm of retardation per mm of glass ceramic article thickness, a haze (%)<0.0994t+0.12 where t is the thickness of the glass ceramic article in mm, and an optical transmission (%)>0.91×10(2-0.03t) of electromagnetic radiation wavelengths from 450 nm to 800 nm, where t is the thickness of the glass ceramic article in mm.

Abstract: A method for ceramming a glass article to a glass-ceramic includes placing a glass article into a heating apparatus, and heating the glass article to a first hold temperature at a first predetermined heating rate. The glass article is held at the first hold temperature for a first predetermined duration. The viscosity of the glass article is maintained within log viscosity ±1.0 poise during the first predetermined duration. The glass article is then heated from the first hold temperature to a second hold temperature at a second predetermined heating rate. The glass article is held at the second hold temperature for a second duration. A density of the glass article is monitored from the heating of the glass article from the first hold temperature through the second duration, and the second duration is ended when an absolute value of a density rate of change of the glass article is less than or equal to 0.10 (g/cm3)/min.