Precursor Glasses and Transparent Glass-Ceramic Articles Formed Therefrom with Improved Mechanical Durability - Patent application

Abstract

The glass-ceramic article comprises a crystalline phase; a residual glass phase; greater than or equal to 52 mol % and less than or equal to 70 mol % SiO2, greater than or equal to 14 mol % and less than or equal to 35 mol % Li2O, greater than or equal to 0.1 mol % and less than or equal to 15 mol % CaO, greater than or equal to 0.5 mol % and less than or equal to 10 mol % ZrO2, and greater than or equal to 0.5 mol % and less than or equal to 5 mol % P2O5.

Description

Priority

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 212139, filed June 18, 2021, the contents of which are relied upon and incorporated herein by reference in their entirety. [Technical field]

[0002] The present specification relates to precursor glass compositions and glass-ceramic articles, and more particularly to precursor glass compositions and ion-exchangeable glass-ceramic articles formed therefrom. [Background technology]

[0003] Glass articles, such as cover glass, glass backplanes, and housings, are used in both consumer and commercial electronic devices, such as smartphones, tablets, portable media players, personal computers, and cameras. Due to the portable nature of these portable devices, they and the glass articles contained therein are particularly susceptible to being accidentally dropped onto hard surfaces, such as the ground. Furthermore, glass articles, such as cover glass, may be provided with "touch" functionality, where the glass article necessarily comes into contact with various objects, including a user's finger and / or stylus instrument. Thus, the glass article must be tough enough to withstand accidental drops and everyday contact without sustaining damage, such as scratches. Indeed, scratches occurring on the surface of a glass article may reduce the strength of the glass article, as they may act as initiation points for cracks that result in catastrophic failure of the glass.

[0004] Additionally, the optical characteristics of the glass article, such as its transmittance, may be an important consideration when the glass article is incorporated as a cover glass in a portable electronic device. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, there is a need for alternative materials that have improved mechanical properties relative to glass, while also having similar optical characteristics to glass. [Means for solving the problem]

[0006] According to a first aspect A1, the glass-ceramic article may include a crystalline phase; a residual glass phase; greater than or equal to 52 mol% and less than or equal to 70 mol% SiO, greater than or equal to 14 mol% and less than or equal to 35 mol% LiO, greater than or equal to 0.1 mol% and less than or equal to 15 mol% CaO, greater than or equal to 0.5 mol% and less than or equal to 10 mol% ZrO, and greater than or equal to 0.5 mol% and less than or equal to 5 mol% PO.

[0007] A second embodiment A2 includes a glass-ceramic article according to the first embodiment A1, wherein the crystalline phase comprises lithium disilicate, the lithium disilicate being present in an amount greater than any other crystalline phase, based on the total weight of the crystalline phases.

[0008] A third embodiment A3 includes a glass-ceramic article according to the second embodiment A2, wherein the particles of lithium disilicate have a particle size equal to or greater than 10 nm and equal to or less than 200 nm.

[0009] A fourth aspect A4 includes the glass-ceramic article according to any one of the first through third aspects A1-A3, wherein the glass-ceramic article includes greater than or equal to 18 mol % and less than or equal to 32 mol % Li2O.

[0010] A fifth aspect A5 includes the glass-ceramic article according to any one of the first through fourth aspects A1-A4, wherein the glass-ceramic article includes greater than or equal to 0.5 mol % and less than or equal to 7 mol % ZrO2.

[0011] A sixth aspect A6 includes the glass-ceramic article according to any one of the first through fifth aspects A1-A5, wherein the glass-ceramic article includes greater than or equal to 1 mol % and less than or equal to 4.5 mol % P2O5.

[0012] A seventh aspect A7 includes the glass-ceramic article according to any one of the first through sixth aspects A1-A6, wherein the glass-ceramic article includes greater than or equal to 0 mol % and less than or equal to 7 mol % Al2O3.

[0013] An eighth embodiment A8 includes the glass-ceramic article according to the seventh embodiment A7, wherein the glass-ceramic article includes greater than or equal to 0.5 mol % and less than or equal to 5 mol % Al2O3.

[0014] A ninth embodiment A9 includes the glass-ceramic article according to any one of the first through eighth embodiments A1-A8, wherein the molar ratio of Al2O3 to SiO2 is greater than or equal to 0 and less than or equal to 0.2.

[0015] A tenth embodiment A10 includes the glass-ceramic article according to any one of the first through ninth embodiments A1-A9, wherein R2O is equal to or greater than 14 mol % and equal to or less than 40 mol %, where R2O is the sum of Li2O, Na2O, and K2O.

[0016] An eleventh embodiment A11 includes the glass-ceramic article according to any one of the first through tenth embodiments A1-A10, wherein the molar ratio of Li2O to SiO2 is greater than or equal to 0.2 and less than or equal to 0.7.

[0017] A twelfth embodiment A12 includes the glass-ceramic article according to any one of the first through eleventh embodiments A1-A11, wherein R′O is equal to or greater than 0.1 mol % and equal to or less than 15 mol %, and R′O is the sum of CaO, MgO, ZnO, SrO, and BaO.

[0018] A thirteenth embodiment A13 includes the glass-ceramic article according to any one of the first through twelfth embodiments A1-A12, wherein a molar ratio of R'O to SiO2 is greater than or equal to 0 and less than or equal to 0.3, and R'O is the sum of CaO, MgO, ZnO, SrO, and BaO.

[0019] A fourteenth aspect A14 includes the glass-ceramic article according to any one of the first through thirteenth aspects A1-A13, wherein the glass-ceramic article includes greater than or equal to 0 mol % and less than or equal to 6 mol % La2O3.

[0020] A fifteenth aspect A15 is a glass-ceramic article comprising 0 mol % or more and 5 mol % or less of F. - The glass-ceramic article according to any one of the first to fourteenth aspects A1-A14, comprising:

[0021] A sixteenth embodiment A16 includes the glass-ceramic article according to any one of the first through fifteenth embodiments A1-A15, wherein the glass-ceramic article includes greater than or equal to 0 mol % and less than or equal to 5 mol % Na2O, and greater than or equal to 0 mol % and less than or equal to 5 mol % K2O.

[0022] A seventeenth embodiment A17 includes the glass-ceramic article according to any one of the first through sixteenth embodiments A1-A16, wherein the glass-ceramic article includes ≧0 mol % and ≦6 mol % MgO, ≧0 mol % and ≦5 mol % ZnO, ≧0 mol % and ≦6 mol % SrO, and ≧0 mol % and ≦6 mol % BaO.

[0023] An eighteenth embodiment A18 includes the glass-ceramic article according to any one of the first through seventeenth embodiments A1-A17, wherein a crystalline phase of the glass-ceramic article includes lithium metasilicate, lithium phosphate, petalite, β-quartz, apatite, or a combination thereof.

[0024] A nineteenth aspect A19 includes the glass-ceramic article according to any one of the first to eighteenth aspects A1-A18, wherein the average transmittance of the glass-ceramic article is greater than or equal to 50% and less than or equal to 95% over the wavelength range from 400 nm to 800 nm, measured at an article thickness of 0.8 mm.

[0025] A twentieth embodiment, A20, relates to the fracture toughness K of the glass-ceramic article, as measured by the double torsion method. IC , but 1.0MPa m 1 / 2 The present invention includes a glass-ceramic article according to any one of the first to nineteenth aspects A1 to A19.

[0026] A twenty-first embodiment A21 includes the glass-ceramic article according to any one of the first through twentieth embodiments A1-A20, wherein the elastic modulus of the glass-ceramic article is 100 GPa or greater.

[0027] According to a twenty-second aspect A22, the glass composition may include 52 mol% to 70 mol% SiO2, 14 mol% to 35 mol% Li2O, 0.1 mol% to 15 mol% CaO, 0.5 mol% to 10 mol% ZrO2, and 0.5 mol% to 5 mol% P2O5.

[0028] A twenty-third embodiment A23 includes the glass composition according to the twenty-second embodiment A22, wherein the glass composition includes ≧18 mol % and ≦32 mol % Li2O.

[0029] A twenty-fourth embodiment A24 includes a glass composition according to the twenty-second embodiment A22 or the twenty-third embodiment A23, wherein the glass composition includes 0.5 mol % or more and 7 mol % or less of ZrO2.

[0030] A twenty-fifth aspect A25 comprises the glass composition according to any one of the twenty-second to twenty-fourth aspects A22-A24, in which the glass composition comprises 1 mol % or more and 4.5 mol % or less of P2O5.

[0031] A twenty-sixth aspect A26 comprises the glass composition according to any one of the twenty-second to twenty-fifth aspects A22 to A25, in which the glass composition comprises 0 mol % or more and 7 mol % or less of Al2O3.

[0032] A twenty-seventh aspect A27 includes the glass composition according to the twenty-sixth aspect A26, wherein the glass composition includes 0.5 mol % or more and 4 mol % or less of Al2O3.

[0033] A twenty-eighth embodiment A28 comprises the glass composition according to any one of the twenty-second to twenty-seventh embodiments A22-A27, in which the molar ratio of Al2O3 to SiO2 is equal to or greater than 0 and equal to or less than 0.2.

[0034] A twenty-ninth embodiment A29 includes the glass composition according to any one of the twenty-second to twenty-eighth embodiments A22 to A28, in which R2O is 14 mol % or more and 40 mol % or less, and R2O is the sum of Li2O, Na2O, and K2O.

[0035] A thirtieth embodiment A30 comprises the glass composition according to any one of the twenty-second to twenty-ninth embodiments A22-A29, in which the molar ratio of Li2O to SiO2 is equal to or greater than 0.2 and equal to or less than 0.7.

[0036] A thirty-first embodiment A31 includes a glass composition according to any one of the twenty-second to thirtieth embodiments A22 to A30, in which R′O is 0.1 mol % or more and 15 mol % or less, and R′O is a total of CaO, MgO, ZnO, SrO, and BaO.

[0037] A thirty-second embodiment A32 includes a glass composition according to any one of the twenty-second to thirty-first embodiments A22 to A31, in which the molar ratio of R'O to SiO2 is greater than or equal to 0 and less than or equal to 0.3, and R'O is the sum of CaO, MgO, ZnO, SrO, and BaO.

[0038] A thirty-third aspect A33 comprises the glass composition according to any one of the twenty-second to thirty-second aspects A22-A32, in which the glass composition comprises 0 mol % or more and 6 mol % or less of La2O3.

[0039] The thirty-fourth embodiment A34 is a glass composition comprising 0 mol % or more and 5 mol % or less of F. - The glass composition according to any one of the twenty-second to thirty-third aspects A22 to A33, comprising:

[0040] A thirty-fifth embodiment A35 includes a glass composition according to any one of the twenty-second to thirty-fourth embodiments A22-A34, in which the glass composition includes 0 mol % or more and 5 mol % or less of Na2O and 0 mol % or more and 5 mol % or less of K2O.

[0041] A thirty-sixth embodiment, A36, comprises a glass composition according to any one of the twenty-second to thirty-fifth embodiments, A22 to A35, in which the glass composition comprises 0 mol % or more and 6 mol % or less of MgO, 0 mol % or more and 5 mol % or less of ZnO, 0 mol % or more and 6 mol % or less of SrO, and 0 mol % or more and 6 mol % or less of BaO.

[0042] According to a thirty-seventh aspect A37, a method of forming a glass-ceramic article includes the steps of heating a precursor glass article in a furnace to a nucleation temperature at a rate of at least 1 °C / min and at most 10 °C / min, wherein the precursor glass article is made from a precursor glass composition comprising at least 52 mol% and at most 70 mol% SiO, at least 14 mol% and at most 35 mol% LiO, at least 0.1 mol% and at most 15 mol% CaO, at least 0.5 mol% and at most 10 mol% ZrO, and at least 0.5 mol% and at most 5 mol% PO; heating the precursor glass article in a furnace at a rate of at least 1 °C / min and at most 10 °C / min, for a period of at least 0.1 hours and at most 8 hours. maintaining the precursor glass article at a nucleation temperature in a furnace for a period of time to produce a nucleated crystallizable glass article; heating the nucleated crystallizable glass article to a crystallization temperature in a furnace at a rate of at least 1° C. / min and not more than 10° C. / min; maintaining the nucleated crystallizable glass article at the crystallization temperature in a furnace for a period of time of at least 0.25 hours and not more than 4 hours to produce a glass-ceramic article, wherein the glass-ceramic article comprises a crystalline phase and a residual glass phase; and cooling the glass-ceramic article to room temperature.

[0043] A thirty-eighth embodiment A38 includes the method according to the thirty-seventh embodiment A37, wherein the crystalline phase comprises lithium disilicate, and the lithium disilicate is present in an amount greater than any other crystalline phase, based on the total weight of the crystalline phases.

[0044] A thirty-ninth embodiment, A39, includes a method according to the thirty-seventh embodiment, A37 or the thirty-eighth embodiment, A38, further including strengthening the glass-ceramic article in an ion exchange bath at a temperature of 350° C. or more and 500° C. or less for a period of 2 hours or more and 12 hours or less to form an ion-exchanged glass-ceramic article.

[0045] A fortieth embodiment A40 includes the method according to the thirty-ninth embodiment A39, wherein the ion exchange bath includes KNO3.

[0046] A forty-first embodiment A41 includes the method according to the fortieth embodiment A40, wherein the ion exchange bath comprises NaNO3.

[0047] A forty-second embodiment, A42, includes the method according to any one of the thirty-seventh to forty-first embodiments, A37-A41, wherein the average transmittance of the glass-ceramic article is greater than or equal to 50% and less than or equal to 95% over the wavelength range from 400 nm to 800 nm, measured at an article thickness of 0.8 mm.

[0048] The forty-third embodiment A43 relates to a glass-ceramic article having a fracture toughness K measured by a double torsion method. IC , but 1.0MPa m 1 / 2 The present invention includes a method according to any one of the thirty-seventh to forty-second aspects A37 to A42 as described above.

[0049] A forty-fourth embodiment, A44, includes the method according to any one of the thirty-seventh through forty-third embodiments, A37-A43, wherein the elastic modulus of the glass-ceramic article is 100 GPa or greater.

[0050] A forty-fifth embodiment, A45, relates to a glass-ceramic article having a stored strain energy of 15 J / m 2 The above includes a method according to any one of the 37th to 44th aspects A37 to A44.

[0051] According to a forty-sixth embodiment A46, a consumer electronic device may include a housing having a front, a back, and sides; electronic components at least partially disposed within the housing, the electronic components including at least a controller, a memory, and a display disposed at or adjacent to a front of the housing; and a glass-ceramic article according to any one of the first to twenty-first embodiments A1-A21 disposed over the display and / or forming part of the housing.

[0052] Additional features and advantages of the precursor glass compositions and resulting glass-ceramic articles described herein are set forth in the following detailed description, and in part will be readily apparent to those skilled in the art from that description, or may be learned by practicing the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0053] It will be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments described herein and, together with the description, serve to explain the principles and operation of the claimed subject matter. [Brief description of the drawings]

[0054] [Figure 1] Illustration of frangibility test specimen after frangibility test [Diagram 2] Illustration of a fragile sample after fragility test [Diagram 3] FIG. 1 is a plan view of an electronic device incorporating any of the glass-ceramic articles according to one or more embodiments described herein. [Figure 4] FIG. 4 is a perspective view of the electronic device of FIG. [Diagram 5] 1 is a plot of percent total transmittance and percent diffuse transmittance (y-axis) versus wavelength (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 6] 1 is a plot of percent total transmittance (y-axis) versus wavelength (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 7] 1 is a plot of percent scattering ratio (y-axis) versus wavelength (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 8] 1 is a plot of the XRD spectrum (x-axis: 2θ; y-axis: intensity) of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 9] 1 is a plot of the XRD spectrum (x-axis: 2θ; y-axis: intensity) of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 10] FIG. 1 is a scanning electron microscope (SEM) image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 11] Further enlarged SEM image of Figure 10 [Figure 12] FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 13] Further enlarged SEM image of Figure 12 [Figure 14] FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 15] Further enlarged SEM image of Figure 14 [Figure 16] 1 is a plot of grain size (y-axis) versus nucleation hold time (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 17] 1 is a plot of crystallinity (y-axis) versus nucleation hold time (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 18] 1 is a plot of fracture toughness (y-axis) versus crystallinity (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 19] FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 20]FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 21] FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Figure 22] 1 is a plot of percent transmittance (y-axis) versus wavelength (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 23] 1 is a plot of central tension (y-axis) versus ion exchange time (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 24] 1 is a plot of sodium concentration (y-axis) versus depth (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Diagram 25] 1 is a plot of central tension (y-axis) versus ion exchange time (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 26] 1 is a plot of mass gain (y-axis) versus square root of ion exchange time (x-axis) for glass-ceramic articles produced from precursor glass compositions according to one or more embodiments described herein. [Figure 27] Photographs of glass-ceramic articles made from precursor glass compositions and subjected to fragility testing, according to one or more embodiments described herein. [Figure 28] Photographs of glass-ceramic articles made from precursor glass compositions and subjected to fragility testing, according to one or more embodiments described herein. [Figure 29] Photographs of glass-ceramic articles made from precursor glass compositions and subjected to fragility testing, according to one or more embodiments described herein. [Diagram 30]FIG. 1 shows an optical image of a glass-ceramic article with strong edge illumination produced from a precursor glass composition and subjected to fragility testing, according to one or more embodiments described herein. [Diagram 31] FIG. 1 shows an optical image of a glass-ceramic article with strong edge illumination produced from a precursor glass composition and subjected to fragility testing, according to one or more embodiments described herein. [Diagram 32] FIG. 1 shows an optical image of a glass-ceramic article with strong edge illumination produced from a precursor glass composition and subjected to fragility testing, according to one or more embodiments described herein. [Diagram 33] FIG. 1 shows an optical image of a glass-ceramic article with strong edge illumination produced from a precursor glass composition and subjected to fragility testing, according to one or more embodiments described herein. [Diagram 34] FIG. 1 is a SEM image of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Diagram 35] FIG. 1 is an EDS plot of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. [Diagram 36] FIG. 1 is an EDS plot of a glass-ceramic article produced from a precursor glass composition according to one or more embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] Reference will now be made in detail to various embodiments of precursor glass compositions and glass-ceramic articles formed therefrom having improved mechanical durability. According to embodiments, the glass-ceramic articles include a crystalline phase, a residual glass phase, 52 mol% or more and 70 mol% or less of SiO2, 14 mol% or more and 35 mol% or less of Li2O, 0.1 mol% or more and 15 mol% or less of CaO, 0.5 mol% or more and 10 mol% or less of ZrO2, and 0.5 mol% or more and 5 mol% or less of P2O5. Various embodiments of precursor glass compositions and methods of forming ion-exchangeable glass-ceramic articles therefrom are described herein with specific reference to the accompanying drawings.

[0056] Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0057] Any directional terms used herein - e.g., up, down, right, left, front, back, upper and bottom - are used only with reference to the drawings depicted and are not intended to imply absolute orientation.

[0058] Unless otherwise expressly stated, it is never intended that any method described herein be construed as requiring that its steps be performed in a particular order, or that any particular orientation of any apparatus be required. Thus, where a method claim does not actually recite an order in which its steps must be followed, or an apparatus claim does not actually recite an order or orientation for individual components, or where it is otherwise specifically stated in the claim or description that the steps are to be limited to a particular order, or where a particular order or orientation for the apparatus components is not recited, no order or orientation is ever intended to be implied. This applies to any possible non-expressive criteria of interpretation, including sequence of steps, flow of operations, order of components, or orientation of components; obvious meanings derived from grammatical construction or punctuation; and logical matters regarding the number or type of embodiments described in the specification.

[0059] As used herein, nouns include plural referents unless the context clearly indicates otherwise. Thus, for example, a reference to a component includes aspects having two or more of such components unless the context clearly indicates otherwise.

[0060] The term "substantially free," when used to describe the concentration and / or absence of a particular component in a precursor glass composition and the resulting glass-ceramic article, means that the component is not intentionally added to the precursor glass composition and the resulting glass-ceramic article. However, the precursor glass composition and the resulting glass-ceramic article may contain trace amounts of the component as a contaminant or admixture in amounts less than 0.1 mole percent.

[0061] The terms "0 mol %" and "free," when used to describe the concentration and / or absence of a particular component in the precursor glass composition and the resulting glass-ceramic article, mean that the component is not present in the precursor glass composition and the resulting glass-ceramic article.

[0062] In the embodiments of the precursor glass compositions and resulting glass-ceramic articles described herein, concentrations of components (e.g., SiO, AlO, etc.) are specified in mole percent (mol%) on an oxide basis, unless otherwise specified.

[0063] In embodiments of the precursor glass compositions and resulting glass-ceramic articles described herein, F - Concentrations are specified in mole percent (mol %) unless otherwise specified.

[0064] The term fracture toughness as used herein means K IC The values ​​are referred to as "Double Torsion Technique as a Universal Fracture Toughness Test Method," and are measured using the double torsion technique described in ASTM STP 559, entitled "Double Torsion Technique as a Universal Fracture Toughness Test Method," the contents of which are incorporated herein by reference in their entirety.

[0065] The transmittance data (total transmittance and diffuse transmittance) are measured on a Lambda 950 UV / Vis spectrophotometer manufactured by PerkinElmer Inc. (Waltham, Massachusetts, USA). The Lambda 950 instrument was equipped with a 150 mm linear sphere. Data was collected using an open beam baseline at the sample position and a Spectralon® reference reflectance disk. For total transmittance (Total Tx), the sample is fixed at the entry point of the integrating sphere. For diffuse transmittance (Diffuse Tx), the Spectralon reference reflectance disk above the exit port of the sphere is removed to allow the on-axis light to exit the sphere and enter the light trap. With no sample present, a zero offset measurement of the diffuse portion is taken to determine the efficiency of the light trap. To correct for diffuse transmittance measurements, the formula: Diffuse Tx=Diffuse 測定 -(Zero Offset * Subtract the zero offset contribution from the sample measurements using (%Diffuse Tx / %Total Tx). Measure the scattering ratio for all wavelengths as (%Diffuse Tx / %Total Tx).

[0066] X-ray diffraction (XRD) spectra, as described herein, are measured on a D8 ENDEAVOR X-ray diffraction system equipped with a LYNXEYE XE-T detector manufactured by Bruker Corporation (Billerica, Massachusetts).

[0067] Electron diffraction images using scanning electron microscopy (SEM) as shown and described herein are taken on a ZEISS GeminiSEM 500 scanning electron microscope.

[0068] As described herein, X-ray spectroscopy (EDS) data is collected using Bruker Esprit software by integrating maps of short exposures (8 μm per pixel) over long total run times. EDS data is collected using an electron-optical nanoprobe SEM configuration.

[0069] The term "average transmittance" as used herein refers to the average of transmittance measurements made within a given wavelength range, with each integer wavelength weighted equally. In the embodiments described herein, "average transmittance" is reported over the wavelength range of 400 nm to 800 nm, inclusive.

[0070] The term "transparent," when used to describe a glass-ceramic article formed from the precursor glass compositions described herein, means that the glass-ceramic article has an average transmittance of 85% or greater when measured at normal incidence for light in the wavelength range of 400 nm to 800 nm (endpoints included) at an article thickness of 0.8 mm.

[0071] The term "transparent haze," when used to describe a glass-ceramic article formed from the precursor glass compositions described herein, means that the glass-ceramic article has an average transmission of greater than or equal to 50% and less than 85%, measured at normal incidence for light in the wavelength range of 400 nm to 800 nm (endpoints included) at an article thickness of 0.8 mm.

[0072] The term "semi-transparent," when used to describe a glass-ceramic article formed from the precursor glass compositions described herein, means that the glass-ceramic article has an average transmittance of greater than or equal to 20% and less than 50%, measured at normal incidence for light in the wavelength range of 400 nm to 800 nm (endpoints included) at an article thickness of 0.8 mm.

[0073] The term "opaque", when used to describe a glass-ceramic article formed from the precursor glass compositions described herein, means that the glass-ceramic article has an average transmission of less than 20% when measured at normal incidence for light in the wavelength range of 400 nm to 800 nm (endpoints included) at an article thickness of 0.8 mm.

[0074] As used herein, the term "melting point" refers to the temperature at which the viscosity of the precursor glass composition is 200 poise.

[0075] As used herein, the term "softening point" refers to the point at which the viscosity of the precursor glass composition is less than 1×10 7.6 The softening point is a function of temperature similar to ASTM C1351M, which is 10 7 From 10 9 It is measured according to the parallel plate viscometry method which measures the viscosity of inorganic glasses in poise.

[0076] The term "liquidus viscosity" as used herein refers to the viscosity of a precursor glass composition at the onset of devitrification (ie, the liquidus temperature as determined by gradient furnace measurement per ASTM C829-81).

[0077] The term "liquidus temperature" as used herein refers to the temperature at which the precursor glass composition begins to devitrify as measured according to the gradient furnace method per ASTM C829-81.

[0078] The elastic modulus (also referred to as Young's modulus) of the glass-ceramic articles as described herein is given in units of gigapascals (GPa) and is measured according to ASTM C623.

[0079] The modulus of rigidity of the glass-ceramic articles as described herein is given in units of gigapascals (GPa) and is measured according to ASTM C623.

[0080] Poisson's ratio as described herein is measured in accordance with ASTM C623.

[0081] As used herein, the terms "coefficient of linear thermal expansion" and "CTE" refer to a temperature range of 25° C. to 300° C., as measured in accordance with ASTM E228-85, and expressed as a function of "×10 -7 / ℃".

[0082] Surface compressive stress is measured with a surface stress meter (FSM), such as a commercially available instrument, such as the FSM-6000 manufactured by Orihara Seisakusho Co., Ltd. (Japan). Surface stress measurement relies on the measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass-ceramic article. SOC is then measured according to procedure C (glass disk method) described in ASTM standard C770-16, entitled "Standard Test Method for Measurement of Glass Stress-Optical Coefficient," the contents of which are incorporated herein in their entirety. Depth of compression (DOC) is measured with an FSM in conjunction with a scattered light polarimeter (SCALP), as known in the art. The FSM measures the depth of compression for potassium ion exchange, and the SCALP measures the depth of compression for sodium ion exchange. Maximum central tension (CT) values ​​are measured using SCALP technology, as known in the art. Values ​​reported herein for central tension (CT) refer to maximum central tension unless otherwise noted.

[0083] The terms "depth of compression" and "DOC" refer to the location in a glass-ceramic article where compressive stress transitions to tensile stress.

[0084] The stored strain energy Σ as described herein can be calculated using the following formula (I):

[0085]

number

[0086] In the formula, z * = 0.5t - σ, where t is the thickness of the glass-ceramic article, σ is the compression depth, ν is Poisson's ratio, E is Young's modulus (MPa), and σ is the tensile stress (MPa). The integral is calculated over only the thickness (micrometers) of the tensile region.

[0087] As used herein, "frangibility limit" refers to the median tension or stored strain energy above which a glass-ceramic article exhibits frangible behavior. "Frangibility" or "frangible behavior" refers to a specific fracture behavior of a glass-ceramic article when it is subjected to impact or attack. As used herein, a glass-ceramic article is considered to be resistant to frangibility if it exhibits at least one of the following in the test area as a result of the frangibility test: (1) four or fewer fragments having a maximum dimension of at least 1 mm, and / or (2) a number of branching points equal to or less than the number of crack branches. The fragments, branching points, and crack branches are counted based on any 2 inch by 2 inch (5.08 cm by 5.08 cm) square centered on the impact point. Thus, a glass-ceramic article is considered to be resistant to frangibility if it meets one or both of tests (1) and (2) for any 2 inch by 2 inch (5.08 cm by 5.08 cm) square centered on the impact point where failure occurs, according to the procedure described below. In the fragility test, an impact probe is contacted with the glass-ceramic article and the depth to which the impact probe extends into the glass-ceramic article increases with successive contact repetitions. The gradual increase in impact probe depth allows the damage caused by the impact probe to reach the tensile region while preventing the application of excessive external forces that would prevent accurate determination of the fragility behavior of the glass-ceramic article. In an embodiment, the impact probe depth in the glass-ceramic article will increase by approximately 5 μm with each repetition, with the impact probe being removed from contact with the glass-ceramic article between each repetition. The test area is a random 2 inch by 2 inch (5.08 cm by 5.08 cm) square centered on the impact point.

[0088] FIG. 1 shows the results of a fracturing resistance test. As shown in FIG. 1, the test area is a square centered on the impact point 130, with the side a of the square measuring 2 inches (5.08 cm). The fracturing resistance sample shown in FIG. 1 includes three fragments 142, two crack branches 140, and one branch point 150. Thus, the fracturing resistance sample shown in FIG. 1 includes less than four fragments having a maximum dimension of at least 1 mm, and the number of branch points is less than or equal to the number of crack branches. As used herein, a crack branch emanates from the impact point, and a fragment is considered to be within the test area if any portion of the fragment extends into the test area. Although coatings, adhesive layers, and the like may be used with the strengthened glass-ceramic articles described herein, no such external constraints are used in determining the fracturing or fracturing behavior of the glass-ceramic articles. In some embodiments, a film that does not affect the fracture behavior of the glass-ceramic article may be applied to the glass-ceramic article prior to fracturing resistance testing to prevent the release of fragments from the glass-ceramic article and to increase the safety of the person performing the test.

[0089] A fragile specimen is shown in Figure 2. This fragile specimen contains five fragments 142 with crack branching 140 and three branching points 150, resulting in more branching points than crack branching. Thus, the specimen shown in Figure 2 does not exhibit either less than four fragments or a number of branching points less than the number of crack branches.

[0090] In the fragility test described herein, an impact is delivered to the surface of the glass-ceramic article with just enough force to release the internal stored energy present within the strengthened glass article, i.e., the point impact force is sufficient to initiate at least one new crack in the surface of the strengthened glass sheet and extend that crack through the compressive stress layer into the region under central tension (CT).

[0091] As used herein, the term "particle size" refers to the size of the largest dimension of a particle as measured using scanning electron microscopy as described in MN Rahaman, Ceramic Processing, CRC Press, 2007, p. 107.

[0092] The term "aspect ratio" as used herein refers to the average ratio of the largest dimension to the smallest dimension perpendicular to the largest dimension of a particle as measured using scanning electron microscopy, as described in M. N. Rahaman, Ceramic Processing, CRC Press, 2007, p. 107.

[0093] As used herein, the term "precursor glass composition" refers to a glass composition that is capable of forming a precursor glass article or a glass-ceramic article upon heat treatment.

[0094] As used herein, the term "precursor glass article" refers to a glass article that contains one or more nucleating agents that, upon heat treatment, cause the nucleation of crystalline phases in the glass.

[0095] As used herein, the term "glass-ceramic article" refers to an article formed by heat-treating a glass article formed from a precursor glass composition to induce nucleation of a crystalline phase, such that the glass-ceramic article contains a crystalline phase and a residual glass phase. In embodiments, the glass-ceramic article has a crystallinity of about 1% to about 99%.

[0096] For ease of reading, the term "precursor glass composition" is referred to throughout the detailed description, however, it should be recognized that the glass-ceramic articles described herein are produced by heat-treating a precursor glass article formed from the precursor glass composition.

[0097] Glass-ceramic articles generally have improved fracture toughness compared to articles formed from glasses due to the presence of crystalline grains (which impede crack growth) and the relatively high elastic modulus of the glass-ceramic articles. However, due to the inherent microstructure of glass-ceramic articles, it can be difficult to achieve the desired transparency. Furthermore, alkali oxides present in the precursor glass composition can be included in the crystalline phase after heat treatment and can be unavailable for ion exchange.

[0098] Disclosed herein are precursor glass compositions and glass-ceramic articles formed therefrom that alleviate the above-mentioned problems. Specifically, the precursor glass compositions described herein include relatively high concentrations of Li2O, CaO, ZrO2, and P2O5, and may be subjected to certain heat treatments to form lithium disilicate glass-ceramic articles characterized as transparent or transparent haze. The lithium disilicate nanocrystals have an interlocking microstructure that may help improve the fracture toughness of the glass-ceramic article. "Interlocking microstructure" refers to elongated, randomly oriented nanocrystals that interlock and entangle with each other. This interlocking structure creates a tortuous path for cracks and impedes crack propagation. Additionally, the relatively high amount of lithium disilicate (e.g., present in a greater amount than any other crystalline phase based on the total mass of the crystalline phases) may result in a relatively high modulus of elasticity compared to articles formed from glass alone. The glass-ceramic article has a relatively high amount of Li2O present in the residual glass phase. Therefore, the residual glassy phase can be readily ion-exchanged to achieve relatively high maximum central tension and stored strain energy without becoming susceptible to fracturing.

[0099] The precursor glass compositions and glass-ceramic articles described herein may be described as lithium silicate precursor glass compositions and glass-ceramic articles and include SiO2 and Li2O. In addition to SiO2 and Li2O, the precursor glass compositions and glass-ceramic articles described herein further include ZrO2 and P2O5 to achieve a desired lithium disilicate-containing crystal phase. The precursor glass compositions and glass-ceramic articles described herein further include CaO to improve the melting behavior of the precursor glass composition.

[0100] SiO2 is the main glass former in the precursor glass composition described herein and may function to stabilize the network structure of the glass-ceramic article. The concentration of SiO2 in the precursor glass composition should be high enough (e.g., 52 mol% or more) to form a crystalline phase containing lithium disilicate when the precursor glass composition is subjected to a heat treatment to convert the precursor glass composition into a glass-ceramic article. The concentration of SiO2 may be limited (e.g., 70 mol% or less) to control the melting point of the precursor glass composition, since the melting temperature of pure SiO2 or high SiO2 glasses is undesirably high. Therefore, limiting the concentration of SiO2 may help improve the meltability and formability of the resulting glass-ceramic article.

[0101] Thus, in embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 52 mol% or more and 70 mol% or less of SiO. In embodiments, the concentration of SiO in the precursor glass compositions and the resulting glass-ceramic articles may be 52 mol% or more, 54 mol% or more, or even 56 mol% or more. In embodiments, the concentration of SiO in the precursor glass compositions and the resulting glass-ceramic articles may be 70 mol% or less, 66 mol% or less, or even 62 mol% or less. In embodiments, the concentration of SiO2 in the precursor glass compositions and the resulting glass-ceramic articles can be from 52 mol% to 70 mol%, from 52 mol% to 66 mol%, from 52 mol% to 62 mol%, from 54 mol% to 70 mol%, from 54 mol% to 66 mol%, from 54 mol% to 62 mol%, from 56 mol% to 70 mol%, from 56 mol% to 66 mol%, or even from 56 mol% to 62 mol%, or any and all subranges formed from any of these endpoints.

[0102] Li2O is a constituent in lithium disilicate and is included in the precursor glass compositions described herein to achieve this desired phase. Li2O also aids in the ion exchangeability of the resulting glass-ceramic article. Li2O lowers the softening point of the precursor glass composition, thereby enhancing the formability of the resulting glass-ceramic article. The concentration of Li2O should be high enough (e.g., 14 mol% or more) so that the resulting glass-ceramic article has lithium disilicate present in a large amount relative to other crystalline phases, based on the total mass of the crystalline phases. However, too high a concentration of Li2O (e.g., greater than 35 mol%) can undesirably increase the viscosity of the melt, thereby reducing the formability of the resulting precursor glass and glass-ceramic article.

[0103] Thus, in embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 14 mol% or more and 35 mol% or less Li2O. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 18 mol% or more and 32 mol% or less Li2O. In embodiments, the concentration of Li2O in the precursor glass compositions and the resulting glass-ceramic articles may be 14 mol% or more, 15 mol% or more, 16 mol% or more, 17 mol% or more, 18 mol% or more, 19 mol% or more, 20 mol% or more, 21 mol% or more, 22 mol% or more, 23 mol% or more, or even 24 mol% or more. In embodiments, the concentration of Li2O in the precursor glass compositions and the resulting glass-ceramic articles may be 35 mol% or less, 33 mol% or less, 30 mol% or less, 29 mol% or less, 28 mol% or less, 27 mol% or less, or even 26 mol% or less. In embodiments, the concentration of LiO in the precursor glass compositions and the resulting glass-ceramic articles is from 14 mol% to 35 mol%, from 14 mol% to 33 mol%, from 14 mol% to 30 mol%, from 14 mol% to 29 mol%, from 14 mol% to 28 mol%, from 14 mol% to 27 mol%, from 14 mol% to 26 mol%, from 15 mol% to 35 mol%, from 15 mol% to 33 mol%, from 15 mol% to 30 mol%, from 15 mol% to 29 mol%, from 15 mol% to 28 mol%, from 15 mol% to 27 mol%, from 15 ... and 26 mol% or less, 16 mol% or more and 35 mol% or less, 16 mol% or more and 33 mol% or less, 16 mol% or more and 30 mol% or less, 16 mol% or more and 29 mol% or less, 16 mol% or more and 28 mol% or less, 16 mol% or more and 27 mol% or less, 16 mol% or more and 26 mol% or less, 17 mol% or more and 35 mol% or less, 17 mol% or more and 33 mol% or less, 17 mol% or more and 30 mol% or less, 17 mol% or more and 29 mol% or less, 17 mol% or more and 28 mol% or less, 17 mol% or more and 27 mol% or less, 17 mol% or more and 26 mol% or less, 18 mol% or more and 35 mol% or less, 18 mol% or more and 33 mol% or less,18 mol% or more and 30 mol% or less, 18 mol% or more and 29 mol% or less, 18 mol% or more and 28 mol% or more and 18 mol% or more and 27 mol% or less, 18 mol% or more and 26 mol% or less, 19 mol% or more and 35 mol% or less, 19 mol% or more and 33 mol% or less, 19 mol% or more and 30 mol% or less, 19 mol% or more and 29 mol% or less, 19 mol% or more and 28 mol% or less, 19 mol% or more and 27 mol% or less, 19 mol% or more and 26 mol% or less, 20 mol% or more and 35 mol% or less, 20 mol% or more and 33 mol% or less, 20 mol% or more and 30 mol% or less, 20 mol% or more and 29 mol% or less, 20 mol% or more and 28 mol% or less, 20 mol% or more and 27 mol% or less, 20 mol% or more and 26 mol% or less, 21 mol% or more and 35 mol% or less, 21 mol% or more and 33 mol% or less, 21 mol% or more and 30 mol% or less, 21 mol% or more and 29 mol% or less, 21 mol% or more and 28 mol% or less, 21 mol% or more and 27 mol% or less below, 21 mol% or more and 26 mol% or less, 22 mol% or more and 35 mol% or less, 22 mol% or more and 33 mol% or less, 22 mol% or more and 30 mol% or less, 22 mol% or more and 29 mol% or less, 22 mol% or more and 28 mol% or less, 22 mol% or more and 27 mol% or less, 22 mol% or more and 26 mol% or less, 23 mol% or more and 35 mol% or less, 23 mol% or more and 33 mol% or less, 23 mol% or more and 30 mol% or less, 23 mol% or more and 29 mol% or less, 23 mol% or more and ... and up to 28 mol%, 23 mol% to 27 mol%, 23 mol% to 26 mol%, 24 mol% to 35 mol%, 24 mol% to 33 mol%, 24 mol% to 30 mol%, 24 mol% to 29 mol%, 24 mol% to 28 mol%, 24 mol% to 27 mol%, and even 24 mol% to 26 mol%, or any and all subranges formed from any of these endpoints.

[0104] In embodiments, the molar ratio of the concentration of LiO in the precursor glass composition and the resulting glass-ceramic article to the concentration of SiO in the precursor glass composition and the resulting glass-ceramic article (i.e., LiO (mol %) to SiO (mol %)) may be 0.2 or more and 0.7 or less to achieve the desired lithium disilicate-containing crystal phase. In embodiments, the molar ratio of LiO to SiO in the precursor glass composition and the resulting glass-ceramic article may be 0.2 or more, 0.3 or more, 0.35 or more, or even 0.4 or more. In embodiments, the molar ratio of LiO to SiO in the precursor glass composition and the resulting glass-ceramic article may be 0.7 or less, 0.6 or less, 0.5 or less, or even 0.45 or less. In embodiments, the molar ratio of LiO to SiO in the precursor glass compositions and the resulting glass-ceramic articles can be from 0.2 to 0.7, from 0.2 to 0.6, from 0.2 to 0.5, from 0.2 to 0.45, from 0.3 to 0.7, from 0.3 to 0.6, from 0.3 to 0.5, from 0.3 to 0.45, from 0.35 to 0.7, from 0.35 to 0.6, from 0.35 to 0.5, from 0.35 to 0.45, from 0.45 to 0.7, from 0.35 to 0.6, from 0.35 to 0.5, from 0.35 to 0.45, from 0.4 to 0.7, from 0.4 to 0.6, from 0.4 to 0.5, or even from 0.4 to 0.45, or any and all subranges formed from any of these endpoints.

[0105] The precursor glass compositions and resulting glass-ceramic articles described herein may further include alkali metal oxides other than Li2O, such as Na2O and / or K2O. Na2O reduces the melting point and improves the formability of the resulting glass-ceramic article, in addition to aiding in the ion-exchangeability of the resulting glass-ceramic article. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 0 mol% or more and 5 mol% or less of Na2O. In embodiments, the concentration of Na2O in the precursor glass compositions and resulting glass-ceramic articles may be 0 mol% or more, 0.5 mol% or more, or even 1 mol% or more. In embodiments, the concentration of Na2O in the precursor glass compositions and resulting glass-ceramic articles may be 5 mol% or less, 4 mol% or less, 3 mol% or less, or even 2 mol% or less. In embodiments, the concentration of Na2O in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 0 mol% to 3 mol%, from 0 mol% to 2 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 4 mol%, from 0.5 mol% to 3 mol%, from 0.5 mol% to 2 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 1 mol% to 3 mol%, or even from 1 mol% to 2 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of Na2O.

[0106] K2O promotes ion exchange, increases the compression depth, and reduces the melting point, improving the formability of the resulting glass-ceramic article. However, the addition of K2O may result in too low a surface compressive stress and melting point. In embodiments, the precursor glass composition and the resulting glass-ceramic article may contain 0 mol% or more and 5 mol% or less of K2O. In embodiments, the concentration of K2O in the precursor glass composition and the resulting glass-ceramic article may be 0 mol% or more, 0.5 mol% or more, or even 1 mol% or more. In embodiments, the concentration of K2O in the precursor glass composition and the resulting glass-ceramic article may be 5 mol% or less, 4 mol% or less, 3 mol% or less, or even 2 mol% or less. In embodiments, the concentration of KO in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 0 mol% to 3 mol%, from 0 mol% to 2 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 4 mol%, from 0.5 mol% to 3 mol%, from 0.5 mol% to 2 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 1 mol% to 3 mol%, or even from 1 mol% to 2 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of KO.

[0107] As used herein, R2O is the sum (mol %) of Li2O, Na2O, and K2O present in the precursor glass composition and the resulting glass-ceramic article (i.e., R2O=Li2O(mol %)+Na2O(mol %)+K2O(mol %)). Alkali oxides such as Li2O, Na2O, and K2O lower the softening point and forming temperature of the precursor glass composition, thereby offsetting the increase in the softening point and forming temperature of the precursor glass composition due to the high amount of SiO2 in the precursor glass composition. The softening point and forming temperature can be further lowered by including a combination of alkali oxides (e.g., two or more alkali oxides) in the precursor glass composition, a phenomenon referred to as the "mixed alkali effect." However, too much alkali oxide can increase the average thermal expansion coefficient of the precursor glass composition by more than 100×10 -7 / °C, which would be undesirable.

[0108] In embodiments, the concentration of R2O in the precursor glass compositions and the resulting glass-ceramic articles may be 14 mol% or more and 40 mol% or less. In embodiments, the concentration of R2O in the precursor glass compositions and the resulting glass-ceramic articles may be 14 mol% or more, 16 mol% or more, 18 mol% or more, 20 mol% or more, 22 mol% or more, 24 mol% or more, or even 26 mol% or more. In embodiments, the concentration of R2O in the precursor glass compositions and the resulting glass-ceramic articles may be 40 mol% or less, 37 mol% or less, 35 mol% or less, 33 mol% or less, or even 30 mol% or less. In embodiments, the concentration of R2O in the precursor glass compositions and the resulting glass-ceramic articles is 14 mol% or more and 40 mol% or less, 14 mol% or more and 37 mol% or less, 14 mol% or more and 35 mol% or more, 14 mol% or more and 33 mol% or less, 14 mol% or more and 30 mol% or less, 16 mol% or more and 40 mol% or less, 16 mol% or more and 37 mol% or less, 16 mol% or more and 35 mol% or more, 16 mol% or more and 33 mol% or less, 16 mol% or more and 30 mol% or less, 18 mol% or more and 40 mol% or less, 18 mol% or more and 37 mol% or less, 18 mol% or more and 35 mol% or more, 18 mol% or more and 33 mol% or less, 18 mol% or more and 30 mol% or less, 20 mol% or more and 40 mol% or less, 20 mol% or more and 37 ... and ≦35 mol%, at least 20 mol% and ≦33 mol%, at least 20 mol% and ≦30 mol%, at least 22 mol% and ≦40 mol%, at least 22 mol% and ≦37 mol%, at least 22 mol% and ≦35 mol%, at least 22 mol% and ≦33 mol%, at least 22 mol% and ≦30 mol%, at least 24 mol% and ≦40 mol%, at least 24 mol% and ≦37 mol%, at least 24 mol% and ≦35 mol%, at least 24 mol% and ≦33 mol%, at least 24 mol% and ≦30 mol%, at least 26 mol% and ≦40 mol%, at least 26 mol% and ≦37 mol%, at least 26 mol% and ≦35 mol%, at least 26 mol% and ≦33 mol%, and even at least 26 mol% and ≦30 mol%, or any and all sub-ranges formed from any of these endpoints.

[0109] The precursor glass compositions and resulting glass-ceramic articles described herein further include CaO. CaO reduces the viscosity of the precursor glass composition, which may improve the formability, strain point and Young's modulus of the resulting glass-ceramic article, and improve ion-exchangeability. However, adding too much CaO to the precursor glass composition reduces the diffusivity of sodium and potassium ions in the precursor glass composition, which in turn adversely affects the ion-exchange performance (i.e., ability to exchange ions) of the resulting glass-ceramic article.

[0110] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may include 0.1 mol% or more and 15 mol% or less of CaO. In embodiments, the concentration of CaO in the precursor glass compositions and the resulting glass-ceramic articles may be 0.1 mol% or more, 0.5 mol% or more, 1 mol% or more, 2 mol% or more, 3 mol% or more, 4 mol% or more, 5 mol% or more, or even 6 mol% or more. In embodiments, the concentration of CaO in the precursor glass compositions and the resulting glass-ceramic articles may be 15 mol% or less, 13 mol% or less, 10 mol% or less, 9 mol% or less, 8 mol% or less, or even 7 mol% or less.In embodiments, the concentration of CaO in the precursor glass compositions and the resulting glass-ceramic articles is from 0.1 mol% to 15 mol%, from 0.1 mol% to 13 mol%, from 0.1 mol% to 10 mol%, from 0.1 mol% to 9 mol%, from 0.1 mol% to 8 mol%, from 0.1 mol% to 7 mol%, from 0.5 mol% to 15 mol%, from 0.5 mol% to 13 ... .5 mol% or more and 10 mol% or less, 0.5 mol% or more and 9 mol% or less, 0.5 mol% or more and 8 mol% or less, 0.5 mol% or more and 7 mol% or less, 1 mol% or more and 15 mol% or less, 1 mol% or more and 13 mol% or less, 1 mol% or more and 10 mol% or less, 1 mol% or more and 9 mol% or less, 1 mol% or more and 8 mol% or less, 1 mol% or more and 7 mol% or less, 2 mol% or more and 15 mol% or less, 2 mol% or more and 13 mol% or less, mol% or more and 10 mol% or less, 2 mol% or more and 9 mol% or less, 2 mol% or more and 8 mol% or less, 2 mol% or more and 7 mol% or less, 3 mol% or more and 15 mol% or less, 3 mol% or more and 13 mol% or less, 3 mol% or more and 10 mol% or less, 3 mol% or more and 9 mol% or less, 3 mol% or more and 8 mol% or less, 3 mol% or more and 7 mol% or less, 4 mol% or more and 15 mol% or less, 4 mol% or more and 13 mol% or less, 4 mol% or more and 1 The range may be 0 mol% or less, 4 mol% or more and 9 mol% or less, 4 mol% or more and 8 mol% or more, 4 mol% or more and 7 mol% or less, 5 mol% or more and 15 mol% or less, 5 mol% or more and 13 mol% or more, 5 mol% or more and 10 mol% or more, 5 mol% or more and 9 mol% or less, 5 mol% or more and 8 mol% or more, 5 mol% or more and 7 mol% or less, 6 mol% or more and 15 mol% or less, 6 mol% or more and 13 mol% or more, 6 mol% or more and 10 mol% or more, 6 mol% or more and 9 mol% or less, 6 mol% or more and 8 mol% or less, or even 6 mol% or more and 7 mol% or less, or any and all subranges formed from any of these endpoints.

[0111] The precursor glass compositions and resulting glass-ceramic articles described herein may further comprise divalent cation oxides other than CaO, such as MgO, ZnO, SrO, and / or BaO. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may comprise 0 mol% or more and 6 mol% or less of MgO. In embodiments, the concentration of MgO in the precursor glass compositions and resulting glass-ceramic articles may be 0 mol% or more, 1 mol% or more, 2 mol% or more, or even 3 mol% or more. In embodiments, the concentration of MgO in the precursor glass compositions and resulting glass-ceramic articles may be 6 mol% or less, 5 mol% or less, or even 4 mol% or less. In embodiments, the concentration of MgO in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 6 mol%, from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 1 mol% to 6 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 2 mol% to 6 mol%, from 2 mol% to 5 mol%, from 2 mol% to 4 mol%, from 3 mol% to 6 mol%, from 3 mol% to 5 mol%, or even from 3 mol% to 4 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of MgO.

[0112] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may include 0 mol% or more and 5 mol% or less of ZnO. In embodiments, the concentration of ZnO in the precursor glass compositions and the resulting glass-ceramic articles may be 0 mol% or more, 1 mol% or more, or even 2 mol% or more. In embodiments, the concentration of ZnO in the precursor glass compositions and the resulting glass-ceramic articles may be 5 mol% or less, 4 mol% or less, or even 3 mol% or less. In embodiments, the concentration of ZnO in the precursor glass compositions and the resulting glass-ceramic articles may be 0 mol% or more and 5 mol% or less, 0 mol% or more and 4 mol% or less, 0 mol% or more and 3 mol% or less, 1 mol% or more and 5 mol% or less, 1 mol% or more and 4 mol% or less, 1 mol% or more and 3 mol% or less, 2 mol% or more and 5 mol% or less, 2 mol% or more and 4 mol% or less, 2 mol% or more and 3 mol% or less, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may be substantially free or free of ZnO.

[0113] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may include 0 mol% or more and 6 mol% or less SrO. In embodiments, the concentration of SrO in the precursor glass compositions and the resulting glass-ceramic articles may be 0 mol% or more, 1 mol% or more, 2 mol% or more, or even 3 mol% or more. In embodiments, the concentration of SrO in the precursor glass compositions and the resulting glass-ceramic articles may be 6 mol% or less, 5 mol% or less, or even 4 mol% or less. In embodiments, the concentration of SrO in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 6 mol%, from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 1 mol% to 6 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 2 mol% to 6 mol%, from 2 mol% to 5 mol%, from 2 mol% to 4 mol%, from 3 mol% to 6 mol%, from 3 mol% to 5 mol%, or even from 3 mol% to 4 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of SrO.

[0114] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 0 mol% or more and 6 mol% or less BaO. In embodiments, the concentration of BaO in the precursor glass compositions and the resulting glass-ceramic articles may be 0 mol% or more, 1 mol% or more, 2 mol% or more, or even 3 mol% or more. In embodiments, the concentration of BaO in the precursor glass compositions and the resulting glass-ceramic articles may be 6 mol% or less, 5 mol% or less, or even 4 mol% or less. In embodiments, the concentration of BaO in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 6 mol%, from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 1 mol% to 6 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 2 mol% to 6 mol%, from 2 mol% to 5 mol%, from 2 mol% to 4 mol%, from 3 mol% to 6 mol%, from 3 mol% to 5 mol%, or even from 3 mol% to 4 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of BaO.

[0115] As used herein, R'O is the sum (mol %) of CaO, MgO, ZnO, SrO, and BaO present in the precursor glass composition and the resulting glass-ceramic article (i.e., R'O = CaO (mol %) + MgO (mol %) + ZnO (mol %) + SrO (mol %) + BaO (mol %)). Divalent cation oxides such as CaO, MgO, ZnO, SrO, and BaO may reduce the viscosity of the precursor glass composition, thereby improving the formability, strain point, and Young's modulus of the resulting glass-ceramic article, and improving ion-exchangeability. However, adding too many divalent cation oxides to the precursor glass composition may reduce the diffusivity of sodium and potassium ions in the precursor glass composition, which in turn adversely affects the ion-exchange performance (i.e., ability to exchange ions) of the resulting glass-ceramic article.

[0116] In embodiments, the concentration of R'O in the precursor glass compositions and the resulting glass-ceramic articles may be 0.1 mol% or more and 15 mol% or less. In embodiments, the concentration of R'O in the precursor glass compositions and the resulting glass-ceramic articles may be 0.1 mol% or more, 0.5 mol% or more, 1 mol% or more, or even 2 mol% or more. In embodiments, the concentration of R'O in the precursor glass compositions and the resulting glass-ceramic articles may be 15 mol% or less, 13 mol% or less, 11 mol% or less, 9 mol% or less, or even 7 mol% or less. In embodiments, the concentration of R′O in the precursor glass compositions and the resulting glass-ceramic articles is from 0.1 mol % to 15 mol %, from 0.1 mol % to 13 mol %, from 0.1 mol % to 11 mol %, from 0.1 mol % to 9 mol %, from 0.1 mol % to 7 mol %, from 0.5 mol % to 15 mol %, from 0.5 mol % to 13 mol %, from 0.5 mol % to 11 mol %, from 0.5 mol % to 9 ... % to 7 mol %, 1 mol % to 15 mol %, 1 mol % to 13 mol %, 1 mol % to 11 mol %, 1 mol % to 9 mol %, 1 mol % to 7 mol %, 2 mol % to 15 mol %, 2 mol % to 13 mol %, 2 mol % to 11 mol %, 2 mol % to 9 mol %, or even 2 mol % to 7 mol %, or any and all subranges formed from any of these endpoints.

[0117] In embodiments, the molar ratio of the concentration of R'O in the precursor glass composition and the resulting glass-ceramic article to the concentration of SiO2 in the precursor glass composition and the resulting glass-ceramic article (i.e., R'O (mol%) to SiO2 (mol%)) can be 0 or more and 0.3 or less to prevent phase separation in the precursor glass composition and produce a lithium disilicate glass-ceramic article characterized as transparent or transparent haze. A molar ratio of R'O to SiO2 that is too high (e.g., greater than 0.3) can in turn inhibit the formation of lithium disilicate. In embodiments, the molar ratio of R'O to SiO2 in the precursor glass composition and the resulting glass-ceramic article can be 0 or more, 0.05 or more, or even 0.1 or more. In embodiments, the molar ratio of R'O to SiO2 in the precursor glass composition and the resulting glass-ceramic article can be 0.3 or less, 0.2 or less, or even 0.15 or less. In embodiments, the molar ratio of R'O to SiO2 in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 to 0.3, from 0 to 0.2, from 0 to 0.15, from 0.05 to 0.3, from 0.05 to 0.2, from 0.05 to 0.15, from 0.1 to 0.3, from 0.1 to 0.2, or even from 0.1 to 0.15, or any and all subranges formed from any of these endpoints.

[0118] The precursor glass compositions and resulting glass-ceramic articles described herein further include ZrO2. ZrO2 may help reduce the grain size of the lithium disilicate, which may be important for the formation of transparent or transparent haze glass-ceramic articles. ZrO2, like SiO2, may act as a network former, thereby reducing devitrification during molding and improving the stability of the glass by lowering the liquidus temperature. The addition of ZrO2 may also improve the chemical durability of the resulting glass-ceramic article. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 0.5 mol% or more and 10 mol% or less of ZrO2. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 0.5 mol% or more and 7 mol% or less of ZrO2. In embodiments, the concentration of ZrO2 in the precursor glass compositions and resulting glass-ceramic articles may be 0.5 mol% or more, 1 mol% or more, 1.5 mol% or more, or even 2 mol% or more. In embodiments, the concentration of ZrO2 in the precursor glass compositions and the resulting glass-ceramic articles may be 10 mol% or less, 7 mol% or less, 5 mol% or less, or even 4 mol% or less. In embodiments, the concentration of ZrO2 in the precursor glass compositions and the resulting glass-ceramic articles can be from 0.5 mol% to 10 mol%, from 0.5 mol% to 7 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 4 mol%, from 1 mol% to 10 mol%, from 1 mol% to 7 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 1.5 mol% to 10 mol%, from 1.5 mol% to 7 mol%, from 1.5 mol% to 5 mol%, from 1.5 mol% to 4 mol%, from 2 mol% to 10 mol%, from 2 mol% to 7 mol%, from 2 mol% to 5 mol%, or even from 2 mol% to 4 mol%, or any and all subranges formed from any of these endpoints.

[0119] The precursor glass compositions and resulting glass-ceramic articles described herein further include P2O5. P2O5 functions as a nucleating agent that causes bulk nucleation of crystalline phases in the glass, thereby converting the precursor glass composition to a glass-ceramic article. The concentration of P2O5 in the precursor glass composition should be high enough (e.g., greater than 0.5 mol%) to effect crystallization. The concentration of P2O5 may be limited (e.g., to 5 mol% or less) to reduce devitrification during forming and reduce the liquidus temperature. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 0.5 mol% or more and 5 mol% or less of P2O5. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 1 mol% or more and 4.5 mol% or less of P2O5. In embodiments, the concentration of P2O5 in the precursor glass compositions and resulting glass-ceramic articles may be 0.5 mol% or more, 1 mol% or more, 1.5 mol% or more, or even 2 mol% or more. In embodiments, the concentration of P2O5 in the precursor glass compositions and the resulting glass-ceramic articles may be 5 mol% or less, 4.5 mol% or less, 4 mol% or less, 3.5 mol% or less, 3 mol% or less, or even 2.5 mol% or less.In embodiments, the concentration of P2O5 in the precursor glass compositions and the resulting glass-ceramic articles is from 0.5 mol% to 5 mol%, from 0.5 mol% to 4.5 mol%, from 0.5 mol% to 4 mol%, from 0.5 mol% to 3.5 mol%, from 0.5 mol% to 3 mol%, from 0.5 mol% to 2.5 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4.5 mol% to 1 mol% to 4 mol%, from 1 mol% to 3.5 mol%, from 1 mol% to 3 mol%, from 1 mol% to 2.5 mol%, % to 5 mol %, 1.5 mol % to 4.5 mol %, 1.5 mol % to 4 mol %, 1.5 mol % to 3.5 mol %, 1.5 mol % to 3 mol %, 1.5 mol % to 2.5 mol %, 2 mol % to 5 mol %, 2 mol % to 4.5 mol %, 2 mol % to 4 mol %, 2 mol % to 3.5 mol %, 2 mol % to 3 mol %, or even 2 mol % to 2.5 mol %, or any and all subranges formed from any of these endpoints.

[0120] The precursor glass compositions and resulting glass-ceramic articles described herein may further include Al2O3. Like SiO2 and ZrO2, Al2O3 may stabilize the glass network, in addition to providing the glass composition with improved mechanical properties and chemical durability. The amount of Al2O3 may also be adjusted to control the viscosity of the glass composition. Al2O3 may be used to ensure that the resulting glass composition has a desired fracture toughness (e.g., 1.0 MPa m 1 / 2 Too much Al2O3 (e.g., greater than 7 mol %) may increase the viscosity of the melt, which may reduce the formability of the glass composition, and the proportion of lithium disilicate crystals may decrease to such an extent that interlocking structures may not form.

[0121] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 0 mol% or more and 7 mol% or less Al2O3. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may comprise 0.5 mol% or more and 5 mol% or less Al2O3. In embodiments, the concentration of Al2O3 in the precursor glass compositions and the resulting glass-ceramic articles may be 0 mol% or more, 0.5 mol% or more, 1 mol% or more, or even 1.5 mol% or more. In embodiments, the concentration of Al2O3 in the precursor glass compositions and the resulting glass-ceramic articles may be 7 mol% or less, 5 mol% or less, or even 3 mol% or less. In embodiments, the concentration of Al2O3 in the precursor glass compositions and the resulting glass-ceramic articles can be from 0 mol% to 7 mol%, from 0 mol% to 5 mol%, from 0 mol% to 3 mol%, from 0.5 mol% to 7 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 3 mol%, from 1 mol% to 7 mol%, from 1 mol% to 5 mol%, from 1 mol% to 3 mol%, from 1.5 mol% to 7 mol%, from 1.5 mol% to 5 mol%, or even from 1.5 mol% to 3 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and the resulting glass-ceramic articles can be substantially free or free of Al2O3.

[0122] In embodiments, the molar ratio of the concentration of Al2O3 in the precursor glass composition and the resulting glass-ceramic article to the concentration of SiO2 in the precursor glass composition and the resulting glass-ceramic article (i.e., Al2O3 (mol %) to SiO2 (mol %)) may be greater than or equal to 0 and less than or equal to 0.2 to achieve the desired lithium disilicate-containing crystal phase. In embodiments, the molar ratio of Al2O3 to SiO2 in the precursor glass composition and the resulting glass-ceramic article may be greater than or equal to 0, or even greater than or equal to 0.01. In embodiments, the molar ratio of Al2O3 to SiO2 in the precursor glass composition and the resulting glass-ceramic article may be less than or equal to 0.2, less than or equal to 0.1, or even less than or equal to 0.05. In embodiments, the molar ratio of Al2O3 to SiO2 in the precursor glass compositions and the resulting glass-ceramic articles can be from greater than or equal to 0 and less than or equal to 0.2, from greater than or equal to 0 and less than or equal to 0.1, from greater than or equal to 0 and less than or equal to 0.05, from greater than or equal to 0.01 and less than or equal to 0.2, from greater than or equal to 0.01 and less than or equal to 0.1, and even from greater than or equal to 0.01 and less than or equal to 0.05, or any and all subranges formed from any of these endpoints.

[0123] The precursor glass compositions and resulting glass-ceramic articles described herein may further include La2O3. La2O3 may partition into the residual glass phase and increase its refractive index, which may better match the refractive index of the crystalline phase to result in a transparent or transparent haze glass-ceramic article. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may include 0 mol% or more and 6 mol% or less of La2O3. In embodiments, the concentration of La2O3 in the precursor glass compositions and resulting glass-ceramic articles may be 0 mol% or more, 0.5 mol% or more, 1 mol% or more, or even 2 mol% or more. In embodiments, the concentration of La2O3 in the precursor glass compositions and resulting glass-ceramic articles may be 6 mol% or less, 5 mol% or less, 4 mol% or less, or even 3 mol% or less. In embodiments, the concentration of La2O3 in the precursor glass composition and the resulting glass-ceramic article may be from 0 mol% to 6 mol%, from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 0 mol% to 3 mol%, from 0.5 mol% to 6 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 4 mol%, from 0.5 mol% to 3 mol%, from 1 mol% to 6 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 1 mol% to 3 mol%, from 2 mol% to 6 mol%, from 2 mol% to 5 mol%, from 2 mol% to 4 mol%, or even from 2 mol% to 3 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass composition and the resulting glass-ceramic article may be substantially free or free of La2O3.

[0124] The precursor glass compositions and resulting glass-ceramic articles described herein are - In some embodiments, F -can produce fluorapatite, which may be important for biomedical applications. - may function as a nucleating agent in the precursor glass composition. - In some embodiments, the precursor glass composition and the resulting glass-ceramic article contain 0 mol % or more and 5 mol % or less of F. - In embodiments, the F in the precursor glass composition and the resulting glass-ceramic article may include - The concentration of F in the precursor glass composition and the resulting glass-ceramic article may be 0 mol% or more, 0.5 mol% or more, 1 mol% or more, or even 2 mol% or more. - The concentration of F in the precursor glass composition and the resulting glass-ceramic article may be 5 mol % or less, 4 mol % or less, or even 3 mol % or less. - The concentration of can be from 0 mol% to 5 mol%, from 0 mol% to 4 mol%, from 0 mol% to 3 mol%, from 0.5 mol% to 5 mol%, from 0.5 mol% to 4 mol%, from 0.5 mol% to 3 mol%, from 1 mol% to 5 mol%, from 1 mol% to 4 mol%, from 1 mol% to 3 mol%, from 2 mol% to 5 mol%, from 2 mol% to 4 mol%, or even from 2 mol% to 3 mol%, or any and all subranges formed from any of these endpoints. In embodiments, the precursor glass compositions and resulting glass-ceramic articles comprise a glass-ceramic article having a concentration of F. - may be substantially free or free of

[0125] In embodiments, the precursor glass compositions and resulting glass-ceramic articles described herein may further include contaminants such as TiO2, MnO, MoO3, WO3, Y2O3, CdO, As2O3, Sb2O3, and sulfur-based compounds such as sulfates, halogens, or combinations thereof. In embodiments, the precursor glass compositions and resulting glass-ceramic articles may be substantially free or free of individual contaminants, combinations of contaminants, or all contaminants. For example, in embodiments, the precursor glass compositions and resulting glass-ceramic articles may be substantially free or free of TiO2, MnO, MoO3, WO3, Y2O3, CdO, As2O3, Sb2O3, and sulfur-based compounds such as sulfates, halogens, or combinations thereof.

[0126] In embodiments, antimicrobial components, chemical fining agents, or other additional components may be included in the precursor glass compositions and the resulting glass-ceramic articles.

[0127] In embodiments, the liquidus temperature of the precursor glass composition may be 900° C. or more, 950° C. or more, or even 1000° C. or more. In embodiments, the liquidus temperature of the precursor glass composition may be 1200° C. or less, 1150° C. or less, or even 1100° C. or less. In embodiments, the liquidus temperature of the precursor glass composition may be 900° C. or more and 1200° C. or less, 900° C. or more and 1150° C. or less, 900° C. or more and 1100° C. or more, 950° C. or more and 1200° C. or less, 950° C. or more and 1150° C. or more, 950° C. or more and 1100° C. or less, 1000° C. or more and 1200° C. or less, 1000° C. or more and 1150° C. or less, or even 1000° C. or more and 1100° C. or less, or any and all subranges formed from any of these endpoints.

[0128] The precursor glass articles described herein or glass-ceramic articles formed therefrom may be of any suitable thickness, which may vary depending on the particular application of the glass-ceramic article. In embodiments, the precursor glass articles or glass-ceramic articles formed therefrom may be of any suitable thickness, which may vary depending on the particular application of the glass-ceramic article. In embodiments, the precursor glass articles or glass-ceramic articles formed therefrom may be of any suitable thickness, which may vary depending on the particular application of the glass-ceramic article. In embodiments, the precursor glass articles or glass-ceramic articles formed therefrom may be of any suitable thickness, which may vary depending on the particular application of the glass-ceramic article. In embodiments, the precursor glass articles or glass-ceramic articles formed therefrom may be of any suitable thickness, which may vary depending on the particular application of the glass-ceramic article. In some embodiments, the thickness may be from 0 to 750 μm, from 750 μm to 6 mm, from 750 μm to 4 mm, from 750 μm to 2 mm, from 750 μm to 1 mm, from 1 mm to 6 mm, from 1 mm to 4 mm, from 1 mm to 2 mm, from 2 mm to 6 mm, from 2 mm to 4 mm, or even from 4 mm to 6 mm, or any and all sub-ranges formed from any of these endpoints.

[0129] As previously noted, glass-ceramic articles formed from the precursor glass compositions described herein may have increased fracture toughness such that the glass-ceramic articles are more damage tolerant. In embodiments, the glass-ceramic articles have a fracture toughness of 1.0 MPa m-2 or greater as measured by the double torsion method. 1 / 2 Fracture toughness K IC In an embodiment, the glass-ceramic article may have a modulus of 1.0 MPa m as measured by the double torsion method. 1 / 2 More than 1.1MPa m 1 / 2 or even 1.2MPa·m 1 / 2 Fracture toughness K IC It may have.

[0130] In embodiments, the elastic modulus of the glass-ceramic article may be 100 GPa or more. In embodiments, the elastic modulus of the glass-ceramic article may be 100 GPa or more, or even 110 GPa or more. In embodiments, the elastic modulus of the glass-ceramic article may be 125 GPa or less, or even 115 GPa or less. In embodiments, the elastic modulus of the glass-ceramic article may be 100 GPa or more and 125 GPa or less, 100 GPa or more and 115 GPa or less, 110 GPa or more and 125 GPa or more and even 110 GPa or more and 115 GPa or less, or any and all subranges formed from any of these endpoints.

[0131] In embodiments, the precursor glass compositions and the resulting glass-ceramic articles may have a modulus of rigidity of 30 GPa or more, or even 40 GPa or more. In embodiments, the glass-ceramic articles may have a modulus of rigidity of 55 GPa or less, or even 50 GPa or less. In embodiments, the glass-ceramic articles may have a modulus of rigidity of 30 GPa or more and 55 GPa or less, 30 GPa or more and 50 GPa or less, 40 GPa or more and 55 GPa or less, or even 40 GPa or more and 50 GPa or less, or any and all subranges formed from any of these endpoints.

[0132] In embodiments, the average transmittance of the glass-ceramic article may be 50% or more and 95% or less of light over the wavelength range of 400 nm to 800 nm, measured at an article thickness of 0.8 mm. In embodiments, the average transmittance of the glass-ceramic article may be 50% or more, 60% or more, 70% or more, or even 80% or more of light over the wavelength range of 400 nm to 800 nm, measured at an article thickness of 0.8 mm. In embodiments, the average transmittance of the glass-ceramic article may be 95% or less, or even 90% or less of light over the wavelength range of 400 nm to 800 nm, measured at an article thickness of 0.8 mm. In embodiments, the average transmittance of the glass-ceramic article, measured at an article thickness of 0.8 mm, can be 50% or more and 95% or less, 50% or more and 90% or less, 60% or more and 95% or less, 60% or more and 90% or less, 70% or more and 95% or less, 70% or more and 90% or less, 80% or more and 95% or less, or even 80% or more and 90% or less, or any and all subranges formed from any of these endpoints, of light over the wavelength range of 400 nm to 800 nm. In embodiments, the glass-ceramic article can be transparent or transparent haze.

[0133] In embodiments, the Poisson's ratio of the glass-ceramic article may be greater than or equal to 0.20, or even greater than or equal to 0.22. In embodiments, the Poisson's ratio of the glass-ceramic article may be less than or equal to 0.25, or even less than or equal to 0.23. In embodiments, the Poisson's ratio of the glass-ceramic article may be greater than or equal to 0.20 and less than or equal to 0.25, greater than or equal to 0.20 and less than or equal to 0.23, greater than or equal to 0.22 and less than or equal to 0.25, or even greater than or equal to 0.22 and less than or equal to 0.23, or any and all subranges formed from any of these endpoints.

[0134] In embodiments, the glass-ceramic articles described herein can be ion-exchanged to strengthen the article. In a typical ion-exchange process, smaller metal ions in a glass-ceramic article are replaced, or "exchanged," with larger metal ions of the same valence in a layer near the outer surface of the glass-ceramic article. The replacement of smaller ions with larger ions creates compressive stresses in the layer of the glass-ceramic article. In embodiments, the metal ions are monovalent metal ions (e.g., Li + , Na + , K + , etc.), and the ion exchange is carried out by immersing the glass-ceramic article in a bath containing a molten salt of at least one of the larger metal ions that are to be exchanged for the smaller metal ions in the glass-ceramic article. + , Tl + , Cu + Other monovalent ions, such as , may be exchanged for monovalent ions. Ion exchange processes used to strengthen glass-ceramic articles may include, but are not limited to, immersion in a single bath or multiple baths of the same or different composition with optional washing and / or slow cooling steps between immersions.

[0135] When exposed to the glass-ceramic article, the ion exchange solution (e.g., a KNO and / or NaNO molten salt bath), according to embodiments, may be at a temperature of 350° C. or more and 500° C. or less, 360° C. or more and 450° C. or less, 370° C. or more and 440° C. or less, 360° C. or more and 420° C. or more and 370° C. or more and 400° C. or less, 375° C. or more and 475° C. or more and 400° C. or less, 410° C. or more and 490° C. or more, 420° C. or more and 480° C. or more, 430° C. or more and 470° C. or more, or even 440° C. or more and 460° C. or less, or any and all subranges formed from any of these endpoints. In embodiments, the glass-ceramic article may be exposed to the ion exchange solution for a period of time of at least 2 hours and not more than 24 hours, at least 2 hours and not more than 12 hours, at least 2 hours and not more than 6 hours, at least 8 hours and not more than 24 hours, at least 6 hours and not more than 24 hours, at least 6 hours and not more than 12 hours, at least 8 hours and not more than 24 hours, and even at least 8 hours and not more than 12 hours, or any and all subranges formed from any of these endpoints.

[0136] The resulting compressive stress layer may have a depth (also referred to as "depth of compression" or "DOC") of 100 μm or more at the surface of the glass-ceramic article at an ion-exchange time of 2 hours. In embodiments, the glass-ceramic article may be ion-exchanged to achieve a compression depth of 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, or even 100 μm or more. In embodiments, the glass-ceramic article has a thickness "t" and may be ion-exchanged to achieve a compression depth of 0.25t or more, 0.27t or more, or even 0.30t or more.

[0137] The occurrence of this surface compression layer is beneficial for better crack resistance and higher flexural strength compared to materials that are not ion-exchanged. The surface compression layer has a higher concentration of ions exchanged into the glass-ceramic article compared to the concentration of ions exchanged into the bulk of the glass-ceramic article (i.e., areas that do not include surface compression).

[0138] In embodiments, glass-ceramic articles produced from the precursor glass compositions described herein may have a surface compressive stress after ion-exchange strengthening of 80 MPa or more, 100 MPa or more, or even 250 MPa or more. In embodiments, the glass-ceramic articles may have a surface compressive stress after ion-exchange strengthening of 1 GPa or less, 750 MPa or less, or even 500 MPa or less. In embodiments, the glass-ceramic articles may have a surface compressive stress after ion-exchange strengthening of 80 MPa or more and 1 GPa or less, 80 MPa or more and 750 MPa or less, 80 MPa or more and 500 MPa or less, 100 MPa or more and 1 GPa or less, 100 MPa or more and 750 MPa or less, 100 MPa or more and 500 MPa or less, 250 MPa or more and 1 GPa or less, 250 MPa or more and 750 MPa or less, or even 250 MPa or more and 500 MPa or less, or any and all sub-ranges formed from any of these endpoints.

[0139] In embodiments, glass-ceramic articles produced from the precursor glass compositions described herein may have a central tension after ion-exchange strengthening of 50 MPa or more, 75 MPa or more, 100 MPa or more, or even 125 MPa or more. In embodiments, glass-ceramic articles produced from the precursor glass compositions described herein may have a central tension after ion-exchange strengthening of 300 MPa or less, 250 MPa or less, or even 200 MPa or less. In embodiments, glass-ceramic articles produced from the precursor glass compositions described herein may have a central tension after ion-exchange strengthening in the range of from 50 MPa to 300 MPa, from 50 MPa to 250 MPa, from 50 MPa to 200 MPa, from 75 MPa to 300 MPa, from 57 MPa to 250 MPa, from 57 MPa to 200 MPa, from 100 MPa to 300 MPa, from 100 MPa to 250 MPa, from 100 MPa to 200 MPa, from 125 MPa to 300 MPa, from 125 MPa to 250 MPa, from 125 MPa to 200 MPa, or any and all sub-ranges formed from any of these endpoints.

[0140] In embodiments, glass-ceramic articles made from the precursor glass compositions described herein have a thermal conductivity of 15 J / m 2 More than 30J / m 2 More than 40J / m 2 More than 50J / m 2 Above, 60J / m 2 More than 70J / m 2 Above, 80J / m 2 Above, 90J / m 2 or even 100 J / m 2 The stored strain energy after ion exchange strengthening may be greater than or equal to 100%.

[0141] In embodiments, glass-ceramic articles made from the precursor glass compositions described herein are formed to have high fracture toughness and high elastic modulus to achieve relatively high maximum central tensile and stored strain energy while remaining below the fragility limit of the glass-ceramic article to limit the risk of fragments being ejected from the glass upon failure.

[0142] In embodiments, a process for producing a glass-ceramic article includes heat treating a precursor glass article formed from a precursor glass composition in a furnace at one or more preselected temperatures for one or more preselected times to induce glass homogenization and crystallization (i.e., nucleation and growth) of one or more crystalline phases (e.g., having one or more compositions, amounts, morphologies, sizes, or size distributions, etc.). In embodiments, the heat treating may include (i) heating the precursor glass article in the furnace to a nucleation temperature at a rate of at least 1° C. / min and not more than 10° C. / min, (ii) maintaining the precursor glass article in the furnace at the nucleation temperature for a time of at least 0.1 hours and not more than 8 hours to produce a nucleated crystallizable glass, (iii) heating the nucleated crystallizable glass article in the furnace to a crystallization temperature at a rate of at least 1° C. / min and not more than 10° C. / min, (iv) maintaining the nucleated crystallizable glass article in the furnace at the crystallization temperature for a time of at least 0.1 hours and not more than 8 hours to produce a glass-ceramic article, and (v) cooling the glass-ceramic article to room temperature.

[0143] In embodiments, the precursor glass article may be heat treated at a relatively low temperature (e.g., a nucleation temperature of 650° C. or less and a crystallization temperature of 800° C. or less) to produce a clear or transparent haze glass-ceramic article. Without intending to be bound by theory, it is believed that the lower temperature limits the grain size of the lithium disilicate upon heat treatment, which aids in obtaining a clear or transparent haze glass-ceramic article. Specifically, grain size increases with temperature due to ion diffusion. At lower temperatures, the growth rate will be slower.

[0144] In embodiments, the nucleation temperature may be 450° C. or more, 500° C. or more, or even 525° C. or more. In embodiments, the nucleation temperature may be 650° C. or less, 600° C. or less, or even 575° C. or less. In embodiments, the nucleation temperature may be 450° C. or more and 650° C. or less, 450° C. or more and 600° C. or less, 450° C. or more and 575° C. or less, 500° C. or more and 650° C. or more, 500° C. or more and 600° C. or less, 500° C. or more and 575° C. or more, 525° C. or more and 650° C. or less, 525° C. or more and 600° C. or less, or even 525° C. or more and 575° C. or less, or any and all subranges formed from any of these endpoints.

[0145] In embodiments, the crystallization temperature may be greater than or equal to 550° C., or even greater than or equal to 600° C. In embodiments, the crystallization temperature may be less than or equal to 800° C., or even less than or equal to 700° C. In embodiments, the crystallization temperature may be greater than or equal to 550° C. and less than or equal to 800° C., greater than or equal to 550° C. and less than or equal to 700° C., greater than or equal to 600° C. and less than or equal to 800° C., or even greater than or equal to 600° C. and less than or equal to 700° C., or any and all subranges formed from any of these endpoints.

[0146] As used herein, heating rate, nucleation temperature, and crystallization temperature refer to the heating rate and temperature of the furnace in which the precursor glass composition or precursor glass article is heat treated.

[0147] The precursor glass composition, as well as the temperature-time profile of the heat treatment step of heating to and maintaining the temperature at the crystallization temperature, are judiciously designed to produce one or more of the following desired attributes: the crystalline phase of the glass-ceramic article, the ratio of the one or more primary crystalline phases and / or the one or more secondary crystalline phases and the residual glass phase, the crystalline phase population of the one or more primary crystalline phases and / or the one or more secondary crystalline phases and the residual glass phase, and the grain size or grain size distribution within the one or more primary crystalline phases and / or the one or more secondary crystalline phases, which in turn may affect the ultimate integrity, quality, color, and / or opacity of the resulting glass-ceramic article.

[0148] The glass-ceramic articles described herein include a crystalline phase and a residual glass phase. In embodiments, the crystalline phase may include lithium disilicate. Lithium disilicate Li2Si2O5 is an orthorhombic crystal based on corrugated plates of {Si2O5} tetrahedral arrangement. The crystals are typically plate-like or lath-like in shape with prominent cleavage planes. Glass-ceramic articles based on lithium disilicate exhibit highly desirable mechanical properties, including high bulk strength and fracture toughness, due to a microstructure of randomly oriented interlocking crystals that allow cracks to propagate through the material in a tortuous path around these crystals.

[0149] In embodiments, lithium disilicate is present in a greater amount than any other crystalline phase, based on the total weight of the crystalline phases in the glass-ceramic article. In embodiments, the total amount of lithium disilicate in the crystalline phases may be 30% or more, 40% or more, 50% or more, 60% or more, or even 70% or more by weight, based on the total weight of the crystalline phases. In embodiments, the total amount of lithium disilicate in the crystalline phases may be 99% or less, 90% or less, or even 80% or less by weight, based on the total weight of the crystalline phases. In embodiments, the total amount of lithium disilicate in the crystalline phase can be greater than or equal to 30% and less than or equal to 99%, greater than or equal to 30% and less than or equal to 90%, greater than or equal to 30% and less than or equal to 80%, greater than or equal to 40% and less than or equal to 99%, greater than or equal to 40% and less than or equal to 90%, greater than or equal to 40% and less than or equal to 80%, greater than or equal to 50% and less than or equal to 99%, greater than or equal to 50% and less than or equal to 90%, greater than or equal to 50% and less than or equal to 80%, greater than or equal to 60% and less than or equal to 99%, greater than or equal to 60% and less than or equal to 90%, greater than or equal to 60% and less than or equal to 80%, greater than or equal to 70% and less than or equal to 99%, greater than or equal to 70% and less than or equal to 90%, or even greater than or equal to 70% and less than or equal to 80%, by weight, based on the total weight of the crystalline phase, or any and all subranges formed from any of these endpoints.

[0150] In embodiments, the crystalline phase of the glass-ceramic article, in addition to lithium disilicate, may further include lithium metasilicate, lithium phosphate, petalite, β-quartz, apatite, or combinations thereof.

[0151] In embodiments, the precursor glass articles described herein may be subjected to specific heat treatments to obtain glass-ceramic articles having relatively small lithium disilicate particles, which may result in transparent or transparent haze glass-ceramic articles. In embodiments, the crystalline phase lithium disilicate particles may have a particle size of 10 nm or more, 25 nm or more, or even 50 nm or more. In embodiments, the crystalline phase lithium disilicate particles may have a particle size of 200 nm or less, 150 nm or less, or even 100 nm or less. In embodiments, the crystalline phase lithium disilicate particles may have a particle size of greater than or equal to 10 nm and less than or equal to 200 nm, greater than or equal to 10 nm and less than or equal to 150 nm, greater than or equal to 100 nm and less than or equal to 25 nm and less than or equal to 200 nm, greater than or equal to 25 nm and less than or equal to 150 nm, greater than or equal to 25 nm and less than or equal to 100 nm, greater than or equal to 50 nm and less than or equal to 200 nm, greater than or equal to 50 nm and less than or equal to 150 nm, and even greater than or equal to 50 nm and less than or equal to 100 nm, or any and all subranges formed from any of these endpoints.

[0152] In embodiments, the crystalline phase lithium disilicate particles may have an aspect ratio of 2:1 or greater, 5:1 or greater, 10:1 or greater, 20:1 or greater, or 25:1 or greater.

[0153] In embodiments, the glass-ceramic article may comprise, by weight (i.e., by weight %) of the glass-ceramic article, 50% or more crystalline phase and 50% or less residual glass phase, 60% or more crystalline phase and 40% or less residual glass phase, 70% or more crystalline phase and 30% or less residual glass phase, 80% or more crystalline phase and 20% or less residual glass phase, or even 90% or more crystalline phase and 10% or less residual glass phase, or any and all subranges formed from any of these endpoints, as determined according to Rietveld analysis of an XRD spectrum.

[0154] The glass-ceramic article may be provided as a sheet, which may then be reshaped by pressing, blowing, bending, sagging, vacuum forming, or other means into a curved or bent piece of uniform thickness.

[0155] The glass-ceramic articles described herein may be used in a variety of applications, including, for example, cover glass or glass backplane applications in consumer or commercial electronic devices, including LCD and LED displays, computer monitors, and automated teller machines (ATMs); touch screen or touch sensor applications, for example, for portable electronic devices, including mobile phones, personal media players, watches, and tablet computers; integrated circuit applications, including, for example, semiconductor wafers; photovoltaic applications; architectural glass applications; automotive or vehicular glass applications; or commercial or household appliance applications. In embodiments, consumer electronic devices (e.g., smartphones, tablet computers, watches, personal computers, ultrabooks, televisions, and cameras), architectural glass, and / or automotive glass may comprise the glass-ceramic articles as described herein.

[0156] Exemplary electronic devices incorporating any of the glass-ceramic articles disclosed herein are shown in Figures 3 and 4. In particular, Figures 3 and 4 show a consumer electronic device 200 comprising a housing 202 having a front surface 204, a back surface 206, and sides 208; electrical components (not shown) at least partially within or completely within the housing, including at least a controller, memory, and a display 210 at or adjacent to the front surface of the housing; and a cover substrate 212 at or over the front surface of the housing so as to cover the display. In an embodiment, at least a portion of at least one of the cover substrate 212 and the housing 202 may comprise any of the glass-ceramic articles disclosed herein. EXAMPLES

[0157] So that the various embodiments may be more readily understood, reference is made to the following examples, which are intended to illustrate various embodiments of the precursor glass compositions and glass-ceramic articles described herein.

[0158] Table 1 shows exemplary and comparative precursor glass compositions (mol %) as well as the liquidus temperatures of the precursor glass compositions.

[0159] [Table 1-1]

[0160] [Table 1-2]

[0161] [Table 1-3]

[0162] [Table 1-4]

[0163] [Table 1-5]

[0164] [Table 1-6]

[0165] [Table 1-7]

[0166] [Table 1-8]

[0167] [Table 1-9]

[0168] Example A - Heat Treatment Table 2 shows the heat treatment schedules for obtaining the exemplary glass-ceramic articles, and the respective properties of the glass-ceramic articles. Exemplary glass-ceramic articles E1-E50 having a thickness of 0.8 mm were formed from the exemplary precursor glass compositions 1-48 listed in Table 1.

[0169] [Table 2-1]

[0170] [Table 2-2]

[0171] [Table 2-3]

[0172] [Table 2-4]

[0173] [Table 2-5]

[0174] [Table 2-6]

[0175] [Table 2-7]

[0176] [Table 2-8]

[0177] [Table 2-9]

[0178] [Table 2-10]

[0179] As shown by the exemplary precursor glass compositions in Table 1 and the glass-ceramic articles in Table 2, the precursor glass compositions described herein may be subjected to specific heat treatments to form glass-ceramic articles that are transparent or transparent haze with improved fracture toughness and elastic modulus.

[0180]

[0036] Referring now to Figure 5, exemplary glass-ceramic article E4 shown in Table 2 formed by subjecting exemplary precursor glass composition 4 to a nucleation hold at 560°C for 4 hours and a crystallization hold at 690°C for 1 hour has an average total transmittance of 90% over the wavelength range of 400 nm to 800 nm, indicating that the particular heat treatment of exemplary precursor glass composition 4 resulted in a transparent glass-ceramic article.

[0037] Referring now to Figure 6, exemplary glass-ceramic article E31 shown in Table 2 formed by subjecting exemplary precursor glass composition 31 to a nucleation hold at 560°C for 4 hours and a crystallization hold at 690°C for 1 hour has an average total transmittance of 90% over the wavelength range of 400 nm to 800 nm, indicating that the particular heat treatment of exemplary precursor glass composition 31 resulted in a transparent haze glass-ceramic article. As shown in Figures 5 and 6, heat treatment of the precursor glass compositions described herein at relatively low temperatures (e.g., nucleation hold at 560°C and crystallization hold at 690°C) results in glass-ceramic articles that are transparent or transparent haze.

[0181] Returning to FIG. 5, exemplary glass-ceramic article E4 had an average diffuse transmittance of 0.18% over the wavelength range of 400 nm to 800 mm. Now referring to FIG. 7, exemplary glass-ceramic article E4 had an average diffuse ratio of 0.13 over the wavelength range of 400 nm to 800 nm. As shown in FIGS. 5 and 7, the precursor glass compositions described herein may be subjected to certain heat treatments to form glass-ceramic articles having relatively low diffuse transmittance and diffuse ratio (meaning less light scattering). Without intending to be bound by theory, the relatively low diffuse transmittance and diffuse ratio may be due to the similarity of the refractive index of the crystalline phases and / or the smaller particle size of the lithium disilicate particles.

[0182] 8, exemplary glass-ceramic article E49, formed by subjecting exemplary precursor glass composition 15 to a nucleation hold of 4 hours at 540° C. and a crystallization hold of 1 hour at 670° C., had lithium disilicate present in the greatest amount and also contained petalite, lithium metasilicate, and lithium phosphate. As shown in FIG. 8, the precursor glass compositions described herein may be subjected to certain heat treatments to produce glass-ceramic articles containing lithium disilicate.

[0183] Referring now to Figure 9, exemplary glass-ceramic article E50 formed by subjecting exemplary precursor glass composition 4 to a nucleation hold at 590°C for 4 hours and a crystallization hold at 690°C for 1 hour had lithium disilicate present in the greatest amount and also included lithium phosphate. Referring now to Figures 10 and 11, exemplary glass-ceramic article E50 included lithium disilicate particles having a particle size in the range of 50 to 100 nm. As shown in Figures 8-11, the precursor glass compositions described herein may be subjected to certain heat treatments to produce glass-ceramic articles including lithium disilicate and having relatively small lithium disilicate particle sizes, which may result in glass-ceramic articles that are transparent or transparent haze.

[0184] Example B: Nucleation Retention 12 and 13, exemplary glass-ceramic article E51 formed by subjecting exemplary precursor glass composition 23 to a nucleation hold at 550° C. for 1 hour included lithium disilicate having a grain size in the range of 30 to 50 nm. Referring now to Figures 14 and 15, exemplary glass-ceramic article E52 formed by subjecting exemplary precursor glass composition 23 to a nucleation hold at 550° C. for 8 hours included lithium disilicate having a grain size in the range of 50 to 200 nm.

[0185] 16, 17, and 18, exemplary precursor glass composition 23 was subjected to a nucleation hold at 550° C. for 0.5, 2, 4, and 8 hours, respectively, to form a glass-ceramic article. As shown in FIG. 16, the particle size of the lithium disilicate did not change significantly with increasing nucleation hold time. As shown in FIG. 17, the crystallinity of the glass-ceramic article increased significantly with increasing nucleation hold time. As shown in FIG. 18, the fracture toughness increased with the crystallinity of the glass-ceramic article.

[0186] As shown in Figures 12-18, subjecting the precursor glass compositions described herein to nucleation holding at relatively low nucleation temperatures will increase the crystallinity of the resulting glass-ceramic article, and therefore increase the fracture toughness, without increasing the lithium disilicate grain size, which will decrease the transmittance of the glass-ceramic article.

[0187] Example C: Crystallization retention Glass-ceramic articles E53, E54, and E55 were formed by subjecting precursor glass composition 23 to a nucleation hold at 550°C for 4 hours and a crystallization hold at 600°C, 750°C, and 850°C for 5 minutes, respectively. Referring now to Figures 19-21, an increase in the lithium disilicate grain size and interconnected microstructure was observed with increasing crystallization temperature. Referring now to Figure 22, the transmittance of the resulting glass-ceramic articles decreases as the crystallization hold temperature increases.

[0188] As shown in Figures 19-22, the precursor glass compositions described herein, when subjected to crystallization hold at a relatively low crystallization temperature, result in glass-ceramic articles with relatively increased transmittance, which may be attributed to the relatively small lithium disilicate grain size.

[0189] Example C: Ion Exchange and Maximum Central Tension Exemplary glass-ceramic article E4 was formed by subjecting exemplary precursor glass composition 4 to a nucleation hold at 560° C. for 4 hours and a crystallization hold at 690° C. for 1 hour, as shown in Table 2. Comparative glass-ceramic article C1 was formed by subjecting comparative precursor glass composition 1 to the same heat treatment used to form exemplary glass-ceramic article E4.

[0190] 23, exemplary glass-ceramic article E4 and comparative glass-ceramic article C1 were ion-exchanged in a 100% NaNO bath at 470° C. for 4 hours, 7 hours, 16 hours, 24 hours, and 32 hours, respectively. Referring now to FIG. 23, exemplary glass-ceramic article E4 achieved a higher maximum center tension than comparative glass-ceramic article C1.

[0191] Now referring to FIG. 24, the exemplary glass-ceramic article E4 and the comparative glass-ceramic article C1 were ion-exchanged in a 60% KNO3 / 40% NaNO3+0.12% LiNO3 molten salt bath for 4 hours, 7 hours, 16 hours, and 24 hours, respectively. Ion-exchanging the exemplary glass-ceramic article E4 for 16 hours resulted in a nearly parabolic profile of exchanged sodium ions in the article. Now referring to FIG. 25, the exemplary glass-ceramic article E4 achieved a higher maximum central tension than the comparative glass-ceramic article C1. As shown in FIG. 26, the exemplary glass-ceramic article E4 exhibited an increase in mass, indicating that there was more Li2O available in the residual glass phase for ion-exchange. The additional Li2O in the residual glass phase would result in a higher central tension.

[0192] The precursor glass compositions described herein were subjected to specific ion exchange conditions to achieve relatively high maximum central tensions, as shown in Figures 23 and 25. Without intending to be bound by theory, it is believed that a relatively large amount of Li2O is present in the residual glass phase due to ion exchange, resulting in an increase in maximum central tension, as evidenced by the mass gain data shown in Figure 26.

[0193] As shown in Figure 26, glass-ceramic articles formed from the precursor glass compositions described herein result in a relatively large amount of Li ions present in the glass-ceramic article that are exchanged for Na ions present in the ion exchange bath, which results in a relatively large maximum central tension. Without intending to be bound by theory, it is believed that the glass-ceramic articles described herein have a relatively large amount of Li2O in the residual glass phase that will be readily ion-exchanged.

[0194] Example D: Ion Exchange and Stored Strain Energy Table 3 shows the ion-exchange conditions for exemplary ion-exchanged glass-ceramic articles and the respective properties of the ion-exchanged glass-ceramic articles. Exemplary glass-ceramic articles E56-E64 were formed from exemplary precursor glass composition 4 listed in Table 1 and subjected to a nucleation hold at 540° C. for 4 hours and a crystallization hold at 670° C. for 1 hour.

[0195] [Table 3-1]

[0196] [Table 3-2]

[0197] As shown by the glass-ceramic articles in Table 3, glass-ceramic articles formed from the precursor glass compositions described herein may achieve high maximum central tension and high stored strain energy when subjected to certain ion exchange conditions.

[0198] 27-29, exemplary glass-ceramic articles E57, E58, and E59 were subjected to fracturing susceptibility testing. As shown in FIGS. 27 and 28, a maximum central tension of 156.9 MPa and a maximum center tension of 33.67 J / m 2 and a maximum central tension of 193.4 MPa and 48.89 J / m 2 No significant cracking (i.e., dicing) was observed in the exemplary glass-ceramic article E58, which has a stored strain energy of 267 MPa and a maximum central tension of 90.87 J / m. As shown in FIG. 2Exemplary glass-ceramic article E64, having a stored strain energy of 1000 .mu.m, exhibited significant cracking (i.e., dicing). As shown in Figures 27-29, glass-ceramic articles formed from the precursor glass compositions described herein may be subjected to certain ion exchange conditions to achieve relatively high central tension and relatively high stored strain energy, which are associated with high fracture toughness and high elastic modulus, while remaining below the fragility threshold. Without intending to be bound by theory, it is believed that the crystal structure of the lithium disilicate crystalline phase allows the glass-ceramic articles described herein to achieve relatively high central tension, fracture toughness, and elastic modulus without becoming fragile.

[0199] Example E: Ion Exchange and Aging Exemplary glass-ceramic articles E65-E68 were formed by subjecting exemplary precursor glass composition 4 to a nucleation hold at 640°C for 4 hours and a crystallization hold at 770°C for 4 hours. Exemplary glass-ceramic articles E66 and E68 were subjected to ion-exchange in a 60% KNO3 / 40% NaNO3+0.12% LiNO3 molten salt bath for 24 hours. Exemplary glass-ceramic articles E65 and E67 were not ion-exchanged. These exemplary glass-ceramic articles were subjected to accelerated aging tests in a chamber at 85°C and 85% humidity. Exemplary glass-ceramic articles E65 and E66 were aged for 72 hours, and exemplary glass-ceramic articles E69 and E70 were aged for 500 hours.

[0200] Referring now to Figures 30-33, no corrosion was observed in any of the exemplary glass-ceramic articles after aging, including ion-exchanged glass-ceramic articles E66 and E68. Referring now to Figures 34-36, NaCl was identified as the predominant phase in ion-exchanged, aged glass-ceramic article E68. Without intending to be bound by theory, it is believed that the predominant phase was NaCl rather than Na2O due to contamination from impurities in the water. As shown in Figures 30-36, glass-ceramic articles formed from the precursor glass compositions described herein can be ion-exchanged and will not corrode, even with high levels of Na2O on the surface of the article.

[0201] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, it is intended that this specification cover modifications and variations of the various embodiments described herein, provided such modifications and variations come within the scope of the appended claims and their equivalents.

[0202] Preferred embodiments of the present invention will be described below in detail.

[0203] EMBODIMENT 1 1. A glass-ceramic article comprising: crystalline phase, Residual glass phase, SiO2, 14 mol% or more and 35 mol% or less of Li2O; 0.1 mol% or more and 15 mol% or less of CaO; 0.5 mol% or more and 10 mol% or less of ZrO2, and 0.5 mol% or more and 5 mol% or less P2O5, 1. A glass-ceramic article comprising:

[0204] EMBODIMENT 2 2. The glass-ceramic article of claim 1, wherein the crystalline phase comprises lithium disilicate, the lithium disilicate being present in an amount greater than any other crystalline phase, based on the total weight of the crystalline phase.

[0205] EMBODIMENT 3 3. The glass-ceramic article of claim 2, wherein the lithium disilicate particles have a size of greater than or equal to 10 nm and less than or equal to 200 nm.

[0206] EMBODIMENT 4 4. The glass-ceramic article of any one of claims 1 to 3, wherein the glass-ceramic article comprises greater than or equal to 18 mol% and less than or equal to 32 mol% LiO.

[0207] EMBODIMENT 5 5. The glass-ceramic article of any one of claims 1 to 4, wherein the glass-ceramic article comprises greater than or equal to 0.5 mol % and less than or equal to 7 mol % ZrO2.

[0208] EMBODIMENT 6 6. The glass-ceramic article of any one of claims 1 to 5, wherein the glass-ceramic article comprises greater than or equal to 1 mol % and less than or equal to 4.5 mol % P2O5.

[0209] EMBODIMENT 7 7. The glass-ceramic article of any one of claims 1 to 6, wherein the glass-ceramic article comprises greater than or equal to 0 mol% and less than or equal to 7 mol% Al2O3.

[0210] EMBODIMENT 8 8. The glass-ceramic article of claim 7, wherein the glass-ceramic article comprises greater than or equal to 0.5 mol % and less than or equal to 5 mol % Al2O3.

[0211] EMBODIMENT 9 9. The glass-ceramic article of any one of the preceding claims, wherein a molar ratio of Al2O3 to SiO2 is greater than or equal to 0 and less than or equal to 0.2.

[0212] EMBODIMENT 10 10. The glass-ceramic article of any one of the preceding claims, wherein R2O is equal to or greater than 14 mol% and equal to or less than 40 mol%, R2O being the sum of Li2O, Na2O, and K2O.

[0213] EMBODIMENT 11 11. The glass-ceramic article of any one of the preceding claims, wherein a molar ratio of LiO to SiO is greater than or equal to 0.2 and less than or equal to 0.7.

[0214] EMBODIMENT 12 12. The glass-ceramic article of any one of the preceding claims, wherein R'O is equal to or greater than 0.1 mol% and equal to or less than 15 mol%, R'O being the sum of CaO, MgO, ZnO, SrO, and BaO.

[0215] EMBODIMENT 13 13. The glass-ceramic article of any one of the preceding claims, wherein a molar ratio of R'O to SiO2 is greater than or equal to 0 and less than or equal to 0.3, and R'O is the sum of CaO, MgO, ZnO, SrO, and BaO.

[0216] EMBODIMENT 14 14. The glass-ceramic article of any one of claims 1 to 13, wherein the glass-ceramic article comprises greater than or equal to 0 mol% and less than or equal to 6 mol% La2O3.

[0217] EMBODIMENT 15 The glass-ceramic article comprises greater than or equal to 0 mol % and less than or equal to 5 mol % F. - 15. The glass-ceramic article of any one of the preceding claims, comprising:

[0218] EMBODIMENT 16 the glass-ceramic article comprising: 0 mol% or more and 5 mol% or less of Na2O, and 0 mol% or more and 5 mol% or less of K2O, 16. The glass-ceramic article of any one of the preceding claims, comprising:

[0219] EMBODIMENT 17 the glass-ceramic article comprising: 0 mol% or more and 6 mol% or less of MgO; 0 mol% or more and 5 mol% or less of ZnO; 0 mol% or more and 6 mol% or less of SrO, and 0 mol% or more and 6 mol% or less of BaO; 17. The glass-ceramic article of any one of the preceding claims, comprising:

[0220] EMBODIMENT 18 18. The glass-ceramic article of any one of the preceding claims, wherein a crystalline phase of the glass-ceramic article comprises lithium metasilicate, lithium phosphate, petalite, β-quartz, apatite, or a combination thereof.

[0221] EMBODIMENT 19 19. The glass-ceramic article of any one of the preceding claims, wherein the glass-ceramic article has an average transmittance, measured at an article thickness of 0.8 mm, of greater than or equal to 50% and less than or equal to 95% over the wavelength range of 400 nm to 800 nm.

[0222] EMBODIMENT 20 The fracture toughness K of the glass-ceramic article measured by the double torsion method IC , but 1.0MPa m 1 / 2 20. The glass-ceramic article of any one of the preceding claims.

[0223] EMBODIMENT 21 21. The glass-ceramic article of any one of the preceding claims, wherein the glass-ceramic article has an elastic modulus of 100 GPa or greater.

[0224] EMBODIMENT 22 In the glass composition, SiO2, 14 mol% or more and 35 mol% or less of Li2O; 0.1 mol% or more and 15 mol% or less of CaO; 0.5 mol% or more and 10 mol% or less of ZrO2, and 0.5 mol% or more and 5 mol% or less P2O5, A glass composition comprising:

[0225] EMBODIMENT 23 23. The glass composition of claim 22, wherein the glass composition comprises greater than or equal to 18 mol % and less than or equal to 32 mol % LiO.

[0226] EMBODIMENT 24 24. The glass composition of claim 22 or 23, wherein the glass composition comprises 0.5 mol % or more and 7 mol % or less of ZrO2.

[0227] EMBODIMENT 25 25. The glass composition of any one of claims 22 to 24, wherein the glass composition comprises ≧1 mol % and ≦4.5 mol % P2O5.

[0228] EMBODIMENT 26 26. The glass composition of any one of claims 22 to 25, wherein the glass composition comprises ≧0 mol % and ≦7 mol % Al2O3.

[0229] EMBODIMENT 27 27. The glass composition of embodiment 26, wherein the glass composition comprises greater than or equal to 0.5 mol % and less than or equal to 4 mol % Al2O3.

[0230] EMBODIMENT 28 28. The glass composition according to any one of embodiments 22 to 27, wherein a molar ratio of Al2O3 to SiO2 is greater than or equal to 0 and less than or equal to 0.2.

[0231] EMBODIMENT 29 29. The glass composition according to any one of embodiments 22 to 28, wherein R2O is equal to or greater than 14 mol % and equal to or less than 40 mol %, R2O being the sum of Li2O, Na2O, and K2O.

[0232] EMBODIMENT 30 30. The glass composition according to any one of embodiments 22 to 29, wherein a molar ratio of Li2O to SiO2 is equal to or greater than 0.2 and equal to or less than 0.7.

[0233] EMBODIMENT 31 31. The glass composition according to any one of embodiments 22 to 30, wherein R′O is 0.1 mol % or more and 15 mol % or less, R′O being the sum of CaO, MgO, ZnO, SrO, and BaO.

[0234] EMBODIMENT 32 32. The glass composition according to any one of embodiments 22 to 31, wherein the molar ratio of R′O to SiO2 is ≧0 and ≦0.3, and R′O is the sum of CaO, MgO, ZnO, SrO, and BaO.

[0235] EMBODIMENT 33 33. The glass composition of any one of claims 22 to 32, wherein the glass composition comprises ≧0 mol % and ≦6 mol % La2O3.

[0236] EMBODIMENT 34 The glass composition contains 0 mol % or more and 5 mol % or less of F. - 34. The glass composition of any one of claims 22 to 33, comprising:

[0237] EMBODIMENT 35 The glass composition comprises: 0 mol% or more and 5 mol% or less of Na2O, and 0 mol% or more and 5 mol% or less of K2O, 35. The glass composition of any one of claims 22 to 34, comprising:

[0238] EMBODIMENT 36 The glass composition comprises: 0 mol% or more and 6 mol% or less of MgO; 0 mol% or more and 5 mol% or less of ZnO; 0 mol% or more and 6 mol% or less of SrO, and 0 mol% or more and 6 mol% or less of BaO; 36. The glass composition of any one of claims 22 to 35, comprising:

[0239] EMBODIMENT 37 1. A method of forming a glass-ceramic article, comprising: heating the precursor glass article in a furnace to a nucleation temperature at a rate of at least 1° C. / min and not more than 10° C. / min, the precursor glass article comprising: SiO2, 14 mol% or more and 35 mol% or less of Li2O; 0.1 mol% or more and 15 mol% or less of CaO; 0.5 mol% or more and 10 mol% or less of ZrO2, and 0.5 mol% or more and 5 mol% or less P2O5, a precursor glass composition comprising: maintaining the precursor glass article at the nucleation temperature in the furnace for a period of at least 0.1 hours and not more than 8 hours to produce a nucleated crystallizable glass article; heating the nucleated crystallizable glass article in the furnace to a crystallization temperature at a rate of at least 1° C. / min and at most 10° C. / min; maintaining the nucleated crystallizable glass article at the crystallization temperature in the furnace for a period of at least 0.25 hours and not more than 4 hours to produce the glass-ceramic article, the glass-ceramic article comprising a crystalline phase and a residual glass phase; and cooling the glass-ceramic article to room temperature; The method includes:

[0240] EMBODIMENT 38 38. The method of embodiment 37, wherein the crystalline phase comprises lithium disilicate, which is present in an amount greater than any other crystalline phase, based on the total weight of the crystalline phase.

[0241] EMBODIMENT 39 39. The method of claim 37 or 38, further comprising strengthening the glass-ceramic article in an ion exchange bath at a temperature of 350° C. or more and 500° C. or less for a period of 2 hours or more and 12 hours or less to form an ion-exchanged glass-ceramic article.

[0242] EMBODIMENT 40 40. The method of embodiment 39, wherein the ion exchange bath comprises KNO.

[0243] EMBODIMENT 41 41. The method of embodiment 40, wherein the ion exchange bath comprises NaNO.

[0244] EMBODIMENT 42 42. The method of any one of claims 37 to 41, wherein the glass-ceramic article has an average transmittance of greater than or equal to 50% and less than or equal to 95% over the wavelength range from 400 nm to 800 nm, measured at an article thickness of 0.8 mm.

[0245] EMBODIMENT 43 The fracture toughness K of the glass-ceramic article measured by the double torsion method IC , but 1.0MPa m 1 / 2 The method according to any one of embodiments 37 to 42, wherein

[0246] EMBODIMENT 44 44. The method of any one of claims 37 to 43, wherein the glass-ceramic article has an elastic modulus of 100 GPa or more.

[0247] EMBODIMENT 45 The stored strain energy of the glass-ceramic article is 15 J / m 2 The method according to any one of embodiments 37 to 44, wherein

[0248] EMBODIMENT 46 In consumer electronics, a housing having a front, a back, and sides; Electronic components disposed at least partially within the housing, the electronic components including at least a controller, a memory, and a display disposed on or adjacent a front surface of the housing; and 22. The glass-ceramic article according to any one of claims 1 to 21, wherein the glass-ceramic article is disposed over the display and / or forms part of the housing. Electronic devices, including [Explanation of symbols]

[0249] 130 Impact Point 140 Crack Branching 142 Debris 150 Junction 200 Consumer Electronics 202 Case 204 Front 206 Back 208 Side 210 Display 212 Cover board

Claims

1. A glass-ceramic article comprising: a crystalline phase, a residual glass phase, SiO in an amount of 52 mol% or more and 70 mol% or less, ２ , Li in an amount of 14 mol% or more and 35 mol% or less, ２ O, CaO in an amount of 0.1 mol% or more and 15 mol% or less, ZrO in an amount of 0.5 mol% or more and 10 mol% or less, ２ , and P in an amount of 0.5 mol% or more and 5 mol% or less, ２ O ５ , a glass-ceramic article.

2. The glass-ceramic article according to claim 1, wherein the crystalline phase contains lithium disilicate, and the lithium disilicate is present in an amount greater than any other crystalline phase based on the total mass of the crystalline phase.

3. The glass-ceramic article according to claim 2, wherein the particles of the lithium disilicate have a particle size of 10 nm or more and 200 nm or less.

4. The glass-ceramic article according to any one of claims 1 to 3, wherein the glass-ceramic article contains Li ２ O in an amount of 18 mol% or more and 32 mol% or less.

5. The glass-ceramic article according to any one of claims 1 to 3, wherein the glass-ceramic article contains ZrO ２ in an amount of 0.5 mol% or more and 7 mol% or less.

6. The glass-ceramic article according to any one of claims 1 to 3, wherein the glass-ceramic article contains P ２ O ５ in an amount of 1 mol% or more and 4.5 mol% or less.

7. Al ２ O ３ to SiO ２The glass-ceramic article according to any one of claims 1 to 3, wherein the molar ratio is 0 or more and 0.2 or less.

8. Li ２ O to SiO ２ The glass-ceramic article according to any one of claims 1 to 3, wherein the molar ratio is 0.2 or more and 0.7 or less.

9. The glass-ceramic article according to any one of claims 1 to 3, wherein the average transmittance of the glass-ceramic article, measured at an article thickness of 0.8 mm, is 50% or more and 95% or less over a wavelength range of 400 nm to 800 nm.

10. The fracture toughness K of the glass-ceramic article measured by the double torsion method ＩＣ is 1.0 MPa·m １／２ or more. The glass-ceramic article according to any one of claims 1 to 3.

Images