Abstract: Ion-exchanged glass ceramic articles described herein have a stress that decreases with increasing distance according to a substantially linear function from a depth of about 0.07 t to a depth of about 0.26 t from the outer surface of the ion-exchanged glass ceramic article from a compressive stress to a tensile stress. The stress transitions from the compressive stress to the tensile stress at a depth of from about 0.18 t to about 0.25 t from the outer surface of the ion-exchanged glass ceramic article. An absolute value of a maximum compressive stress at the outer surface of the ion-exchanged glass article is from 1.8 to 2.2 times an absolute value of a maximum central tension (CT) of the ion-exchanged glass article, and the glass ceramic article has a fracture toughness of 1 MPa?m or more as measured according to the double cantilever beam method.

Abstract: A mold stack for forming 3D glass-based articles includes a plenum and a cooling structure integrated with the plenum. The mold stack includes a mold with a flange that can be used to mount the mold on the plenum. The mold stack includes features to reduce mold warp without significantly increasing thermal mass.

Abstract: A method includes contacting a glass sheet with a forming surface to form a shaped glass article. An effective viscosity of the glass sheet during the contacting step is less than a contact viscosity of the glass sheet in contact with the forming surface during the contacting step.

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 of reworking lithium containing ion exchanged glass articles is provided. The method includes a reverse ion exchange process that returns the glass article to approximately the composition of the glass from which the glass article was produced, before being subjected to ion exchange. The reworked glass articles exhibit a K2O concentration profile comprising a portion wherein a K2O concentration increases to a local K2O concentration maximum.

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: Methods for regenerating poisoned salt bath comprising providing a salt bath comprising at least one of KNO3 and NaNO3, providing an ion-exchangeable substrate comprising lithium cations, contacting at least a portion of the ion-exchangeable substrate with the salt bath, whereby lithium cations in the salt bath diffuse from the ion-exchangeable substrate and are dissolved in the salt bath, and selectively precipitating dissolved lithium cations from the salt bath using phosphate salt. The methods further include preventing or reducing the formation of surface defects in the ion-exchangeable substrate by preventing or reducing the formation of crystals on the surface of the ion-exchangeable substrate upon removal from the salt bath.

Abstract: Glass-based articles comprise stress profiles providing improved scratch resistance. A glass-based article comprises a lithium aluminosilicate composition and a molar ratio of potassium dioxide (K2O) to sodium dioxide (Na2O) averaged over a distance from the surface to a depth of 0.4 micrometers that is greater than or equal to 0 and less than or equal to 1.8. The article comprises sodium having a non-zero varying concentration extending from a surface of the glass-based article to a depth of the glass-based article and a spike depth of layer that is greater than or equal to 4 micrometers and less than or equal to 8 micrometers. The article may comprise an average compressive stress of greater than or equal to 150 MPa over a depth from 15 micrometers to 40 micrometers.

Abstract: A method for determining crystal phases of a glass ceramic sample, including the steps of applying energy to the sample using an excitation source, detecting raw Raman spectral energy that is given off by the sample using a detector, wherein the raw Raman spectral energy includes peak values, determining a plurality of predetermined energy peaks based off a composition of the sample, superimposing the plurality of predetermined energy peaks over the raw Raman spectral energy, applying a baseline value between each predetermined energy peak, subtracting the baseline value from the raw Raman spectral energy, calculating corrected peak values based on the raw Raman spectral energy and baseline value, and determining the crystal phases of the glass ceramic sample based on the corrected peak values.

Abstract: Methods for regenerating poisoned salt bath comprising providing a salt bath comprising at least one of KNO3 and NaNO3, providing an ion-exchangeable substrate comprising lithium cations, contacting at least a portion of the ion-exchangeable substrate with the salt bath, whereby lithium cations in the salt bath diffuse from the ion-exchangeable substrate and are dissolved in the salt bath, and selectively precipitating dissolved lithium cations from the salt bath using phosphate salt. The methods further include preventing or reducing the formation of surface defects in the ion-exchangeable substrate by preventing or reducing the formation of crystals on the surface of the ion-exchangeable substrate upon removal from the salt bath.

Abstract: A three dimensional glass ceramic article with a thickness between 0.1 mm and 2 mm, having a dimensional precision control of less than or equal to ±0.1 mm. A method for forming a three dimensional glass ceramic article including placing a nucleated glass article into a mold, and heating the nucleated glass article to a crystallization temperature, where the nucleated glass article is in the mold during the heating. Then, holding the nucleated glass article at the crystallization temperature for a duration sufficient to crystallize the nucleated glass article and form a three dimensional glass ceramic article, where the nucleated glass article is in the mold during the holding, and removing the three dimensional glass ceramic article from the mold.

Abstract: A cover glass article includes a glass body having a three-dimensional shape, an inside surface, and an outside surface. Each of the inside and outside surfaces has a surface roughness (Ra) less than 1 nm and is free of indentations having diameters larger than 150 ?m.

Abstract: Ion-exchanged glass ceramic articles described herein have a stress that decreases with increasing distance according to a substantially linear function from a depth of about 0.07 t to a depth of about 0.26 t from the outer surface of the ion-exchanged glass ceramic article from a compressive stress to a tensile stress. The stress transitions from the compressive stress to the tensile stress at a depth of from about 0.18 t to about 0.25 t from the outer surface of the ion-exchanged glass ceramic article. An absolute value of a maximum compressive stress at the outer surface of the ion-exchanged glass article is from 1.8 to 2.2 times an absolute value of a maximum central tension (CT) of the ion-exchanged glass article, and the glass ceramic article has a fracture toughness of 1 MPa?m or more as measured according to the double cantilever beam method.

Abstract: An apparatus for locating a preform on a mold includes a preform handling tool and a force sensor coupled to the preform handling tool such that the force sensor is capable of sensing forces applied to the preform during handling of the preform by the preform handling tool. The apparatus includes a control device that is arranged and operable to move the preform handling tool relative to the mold. A method of locating the preform on the mold includes picking up the preform using the preform handling tool and placing the preform in a vicinity of the mold. Positions on the mold are mapped with an edge of the preform with the aid of the force sensor. The preform is paced on the mold according to the mapped positions.

Abstract: According to one embodiment, a method of manufacturing a glass article having a three-dimensional shape includes heating a glass article blank to a temperature above a setting temperature and coupling the glass article blank to an open-faced mold. The open-faced mold includes a molding region that has a three-dimensional shape that generally corresponds to the shape of the glass article and has an anisothermal temperature profile within the molding region. The method further includes maintaining an anisothermal temperature profile along the glass article blank and cooling the glass article blank while the glass article blank is coupled to the molding region of the open-faced mold to set the shape of the glass article.

Abstract: A method includes contacting a glass sheet with a forming surface to form a shaped glass article. An effective viscosity of the glass sheet during the contacting step is less than a contact viscosity of the glass sheet in contact with the forming surface during the contacting step.

Abstract: A cover glass article includes a glass body having a three-dimensional shape, an inside surface, and an outside surface. Each of the inside and outside surfaces has a surface roughness (Ra) less than 1 nm and is free of indentations having diameters larger than 150 ?m.

Abstract: Methods for regenerating poisoned salt bath comprising providing a salt bath comprising at least one of KNO3 and NaNO3, providing an ion-exchangeable substrate comprising lithium cations, contacting at least a portion of the ion-exchangeable substrate with the salt bath, whereby lithium cations in the salt bath diffuse from the ion-exchangeable substrate and are dissolved in the salt bath, and selectively precipitating dissolved lithium cations from the salt bath using phosphate salt. The methods further include preventing or reducing the formation of surface defects in the ion-exchangeable substrate by preventing or reducing the formation of crystals on the surface of the ion-exchangeable substrate upon removal from the salt bath.

Abstract: A method of forming a 3D glass article from a glass sheet includes locating the glass sheet on a mold assembly including a mold surface with a 3D surface profile corresponding to that of the 3D glass article. The glass sheet is heated to a forming temperature. The forming temperature is greater than a temperature of the mold surface. The heated glass sheet is forced onto the mold surface by applying a pressurized gas to a first surface of the glass sheet opposite the mold surface to conform the glass sheet to the mold surface with the glass sheet at the forming temperature that is greater than the temperature of the mold surface.

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.