Glass article including a metal oxide concentration gradient

Abstract

To provide a thin glass-based articles that exhibit improved fracture resistance.SOLUTION: There is provided a glass-based article comprising SiO2 of 40 mol% or more and 80 mol% or less, Na2O of 0 mol% or more and 6 mol% or less, and K2O of less than 2 mol%. A ratio of Li2O (mol%) to R2O (mol%) in the glass-based article is 0.7 or more and 1.0 or less, wherein R2O is the sum of Li2O, Na2O, and K2O in the glass-based article. A stress profile comprises a surface compressive stress (CS) and a maximum central tension (CT), wherein: the maximum CT is 80 MPa or more and 95 MPa or less and the maximum CT is positioned within the glass-based article at a range of 0.4 t or more and 0.6 t or less; the surface compressive stress CS is 200 MPa or more; and a depth of compression (DOC) is 0.14 t or more and 0.25 t or less. The glass-based article is a glass-ceramic comprising an amorphous phase and a crystalline phase.SELECTED DRAWING: None

Description

Cross - reference to related applications

[0001] This application is a divisional application of patent application 2018 - 552206, which claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 62 / 366338, filed on July 25, 2016, and U.S. Provisional Application No. 62 / 320077, filed on April 8, 2016.

Technical Field

[0002] The present disclosure relates to glass - based articles that exhibit improved damage resistance, including improved fracture resistance, and more particularly, to glasses and glass - ceramic articles that exhibit a non - zero metal oxide concentration gradient, i.e., a concentration that varies along a substantial portion of the thickness.

Background Art

[0003] Glass - based articles are often subject to strong impacts that can introduce large scratches within the surface of the article. Such scratches can extend to a depth of about 200 micrometers (microns or μm) from the surface. Heat - tempered glass often exhibits a large compressive stress (CS) layer (e.g., about 21% of the total thickness of the glass), which can prevent the scratch from spreading further into the glass, thereby preventing defects. Thus, heat - tempered glass has traditionally been used to prevent defects caused by the introduction of such scratches into the glass. An example of the stress profile generated by heat - tempering is shown in FIG. 1. In FIG. 1, the heat - treated glass article 100 includes a first surface 101, a thickness t1, and a surface CS 110. The heat - treated glass article 100 exhibits a CS that decreases from the first surface 101 to a depth of compression (DOC) 130 as defined herein, at which depth the stress changes from compression to tensile stress and reaches a maximum center tension (CT) 120.

[0004] Heat tempering currently is limited to thick glassy articles (i.e., glassy articles having a thickness t1 of about 3 millimeters or more) because a sufficient thermal gradient must be formed between the center and the surface of such articles to achieve thermal strengthening and the desired residual stress. Such thick articles are undesirable or not practical in many applications, such as displays (e.g., household electronic devices including mobile phones, tablets, computers, navigation systems, etc.), building components (e.g., windows, shower panels, countertops, etc.), transportation devices (e.g., automobiles, trains, airplanes, ships, etc.), electrical appliances, or any application that requires a thin and lightweight article with excellent fracture resistance.

[0005] Chemical strengthening is not limited by the thickness of the glassy article as is heat tempering, but known chemically strengthened glassy articles do not exhibit the stress profile of heat tempered glassy articles. An example of a stress profile produced by chemical strengthening (e.g., by an ion exchange process) is shown in FIG. 2. In FIG. 2, the chemically strengthened glassy article 200 has a first surface 201, a thickness t2, and a surface CS210. The glassy article 200 exhibits a CS that decreases from the first surface 201 to a DOC230 as defined herein, at which depth the stress changes from compressive to tensile stress and reaches a maximum CT220. As shown in FIG. 2, such a profile exhibits a substantially flat CT region or a CT region having a constant or nearly constant tensile stress along at least a portion of the CT region. Often, known chemically strengthened glassy articles exhibit a lower maximum CT value compared to the maximum center value shown in FIG. 1. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Accordingly, there is a need for thin glassy articles that exhibit improved fracture resistance. MEANS FOR SOLVING THE PROBLEMS

[0007] A first aspect of the present disclosure is a glass article that includes a first surface defining a thickness (t) and a second surface opposing the first surface, has a concentration of metal oxide that is non-zero and varies along a thickness range of from about 0·t to about 0.3·t, has a central tension (CT) region that includes a maximum CT of 71.5 / √(t) or greater, and when the glass article is broken in a measurement by the "fragility test" described in Z. Tang et al., Automated Apparatus for Measuring the Frangibility and Fragmentation of Strengthened Glass. Experimental Mechanics (2014) 54:903 - 912, with the sample dimensions used being 5.08 cm × 5.08 cm (2 inches × 2 inches) square, the glass article breaks into at least 2 fragments / inch² (fragments per square inch). The number of fragments is divided by the area (square inches) of the sample being tested. The change in the metal oxide concentration used here can be referred to as a metal oxide concentration gradient in this specification. In one or more embodiments, the concentration of the metal oxide is non-zero and varies along the overall thickness. In one or more embodiments, the CT region can include a metal oxide that is non-zero and varies along a thickness range of from about 0·t to about 0.3·t. The glass article of one or more embodiments can have a thickness t of about 3 millimeters (mm) or less, 2 mm or less, or about 1 mm or less.

[0008] A second aspect of the present disclosure is a glass article that includes a first surface defining a thickness (t) of about 3 millimeters or less and a second surface opposing the first surface, has a stress profile that spreads along the thickness, and all points of the stress profile between a thickness range of from about 0·t to 0.3·t and beyond 0.7·t to t have a tangent with an absolute value of slope greater than about 0.1 MPa / micrometer, the stress profile has a maximum CS, DOC, and a maximum CT of 71.5 / √(t) or greater, the ratio of the maximum CT to the absolute value of the maximum CS is within a range of about 0.01 to about 0.2, and the DOC is about 0.1·t or greater.

[0009] The third aspect of the present disclosure includes a first surface defining a thickness (t) and a second surface facing the first surface, having a concentration of metal oxide that varies along a thickness range of not zero and from about 0·t to about 0.3·t (or from about 0·t to about 0.4·t or from about 0·t to about 0.45·t), having a surface compressive stress exceeding about 200 MPa, and having a CT region having a maximum CT of 71.5 / √(t) or more, and relates to a glass article.

[0010] The fourth aspect of the present disclosure is a glass article including a first surface defining a thickness (t) and a second surface facing the first surface, and including a metal oxide that forms a concentration gradient, wherein the concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface and increases from that value to the second surface, and in that case, the concentration of the metal oxide at that point is not zero, and the glass article has a stored tensile energy exceeding about 0 J / m 2 and less than 20 J / m 2 and a Young's modulus of about 70 GPa or more.

[0011] The fifth aspect of the present disclosure is a glass article including a first surface defining a thickness (t) of about 3 millimeters or less and a second surface facing the first surface, having a stress profile that spreads along the thickness, wherein all points of the stress profile between the thickness ranges from about 0·t to 0.3·t and exceeding 0.7·t have a tangent with an absolute value of slope exceeding about 0.1 MPa / micrometer, the stress profile having a maximum CS, DOC, and maximum CT, the ratio of the maximum CT to the absolute value of the maximum CS being within the range of about 0.01 to about 0.2, the DOC being about 0.1·t or more, and the glass article having a stored tensile energy exceeding about 0 J / m 2 and less than 20 J / m 2 and a Young's modulus of about 70 GPa or more. In one or more embodiments, the glass article has a non-zero concentration of metal oxide that varies continuously throughout the thickness. In some cases, the non-zero concentration of metal oxide varies continuously along a thickness portion of less than about 10 micrometers.

[0012] A sixth aspect of the present disclosure relates to a glass article having a stress profile including a CS region and a CT region, where the CT region is defined by the equation: Stress(x) = MaxT - (((CTn·(n + 1)) / 0.5n)·|(x / t) - 0.5|n) (where MaxT is the maximum tensile value, CTn is a positive value in MPa and is less than or equal to MaxT, x is the position along the thickness (t) in micrometers, and n is between 1.5 and 5.) It is approximated by. In some embodiments, the maximum CT value is in the range of about 50 MPa to about 250 MPa, and the maximum CT value is the value at a depth within the range of about 0.4·t to about 0.6·t. In one or more embodiments, from a thickness within the range of about 0·t to about 0.1·t, the stress profile includes a slope within the range of about 20 MPa / micrometer to about 200 MPa / micrometer. In one or more embodiments, the stress profile is approximated by a plurality of error functions measured from 0.5·t to the surface.

[0013] According to one or more embodiments of the glass article described herein, monovalent ions of a metal oxide generate stress along a thickness range (i.e., about 0·t to about 0.3·t, about 0·t to about 0.4·t, or about 0·t to about 0.45·t). The concentration of the metal oxide in one or more embodiments decreases from the first surface to a value at a point between the first surface and the second surface and increases from that value to the second surface.

[0014] In one or more embodiments, the concentration of the metal oxide is about 0.05 mol% or more throughout the thickness. For example, in one or more embodiments, the concentration of the metal oxide on the first surface is about 1.5 times (or more) the concentration of the metal oxide at a depth corresponding to about 0.5·t. In an exemplary embodiment, the glass article has a total metal oxide concentration in the range of about 1 mol% to about 15 mol%. In one or more embodiments, examples of the metal oxide include any one or more of Li2O, Na2O, K2O, Rb2O, and Cs2O. In one or more embodiments, the monovalent ions of the metal oxide have the largest ionic diameter among all the metal oxides in the glass substrate or article.

[0015] In one or more embodiments, the CT region contains a metal oxide that is non-zero and varies along a thickness range of about 0·t to about 0.3·t. In one or more embodiments of the glass article described herein, the maximum CT is 71.5 / √(t) (MPa) or more, where "71.5" is in the unit of MPa·(mm)0.5 and "t" is in millimeters (mm).

[0016] Some embodiments of the glass article have a first metal oxide concentration and a second metal oxide concentration. In some embodiments, the first metal oxide concentration ranges from about 0 mol% to about 15 mol% in a first thickness range of about 0·t to about 0.5·t. In some embodiments, the second metal oxide concentration ranges from about 0 mol% to about 10 mol% in a second thickness range of about 0 micrometers to about 25 micrometers. The glass article may optionally contain any third metal oxide.

[0017] In one or more embodiments, the glass article described herein can exhibit a surface compressive stress (CS) greater than the maximum CT. One or more embodiments of the glass article described herein can include a surface CS of about 300 MPa or greater. In some examples, this surface CS is exhibited when the glass article has a thickness of about 2 mm or less. In one or more embodiments, the glass article exhibits a combination of a surface CS of about 200 MPa or greater and a chemical depth of the layer of about 0.4·t or greater. In one or more embodiments, the glass article has a CS that extends from the first surface to the DOC, and the DOC is about 0.1·t or greater. In some examples, the ratio of the maximum CT to the absolute value of the surface CS is in the range of about 0.1 to about 0.8.

[0018] In one or more embodiments, the glass article has an amorphous structure. In some embodiments, the glass article may have a crystalline structure.

[0019] In one or more embodiments, the glass article described herein can exhibit a transmittance of about 88% or greater over a wavelength range of about 380 nm to about 780 nm. In some examples, the glass article described herein can exhibit CIELAB color space coordinates under the CIE illuminant F02 of an L* value of about 88° or greater, an a* value in the range of about -3° to about +3° and a b* value in the range of about -6° to about +6°. In one or more embodiments, the glass article described herein can have a Young's modulus of about 70 GPa or greater. In some embodiments, the glass article described herein has a liquid viscosity of less than about 100 kilopascals (kP). In one or more embodiments, the glass article described herein has a viscosity of about 0.65 MPa·m 1 / 2Exhibit the above fracture toughness (K1C). In one or more embodiments, the glass articles described herein include a composition having a combined amount of Al2O3 and Na2O of about 15 mol% or less, a composition containing about 4 mol% or more of Na2O, a composition containing any one or more of B2O3 and ZnO, and any one or two or more of a composition substantially free of P2O5. In one or more embodiments, the glass article has a monovalent ion diffusivity of about 450 μm 2 / hour (square micrometers per hour) or more of monovalent ions (e.g., sodium ions or potassium ions). In some embodiments, this monovalent ion diffusivity is shown in combination with a DOC exceeding about 0.15·t and a surface CS that is 1.5 times or more of the maximum CT.

[0020] In one or more embodiments, the glass articles described herein exhibit a certain fracture behavior. For example, in one or more embodiments, in the measurement by the "fragility test" described in Z. Tang et al., Automated Apparatus for Measuring the Frangibility and Fragmentation of Strengthened Glass. Experimental Mechanics (2014) 54:903 - 912, when the sample size used is 5.08 cm × 5.08 cm (2 inches × 2 inches) square and the glass article is broken by a single event (i.e., a single impact such as dropping or colliding with an instrument once), the glass article is broken into at least 2 fragments / inch² (fragments per square inch). The number of fragments is divided by the area (square inches) of the sample being tested. In some embodiments, when the glass article is broken, with the sample size used being 5.08 cm × 5.08 cm (2 inches × 2 inches) square, the glass article is broken into at least 1 fragment / inch² to 40 fragments / inch² (fragments per square inch).

[0021] The seventh aspect of the present disclosure relates to the use of a glass substrate in a strengthened glass article. In one or more embodiments, the glass substrate comprises, in mole %, an amount of SiO2 in the range of about 68 to about 75, an amount of Al2O3 in the range of about 12 to about 15, an amount of B2O3 in the range of about 0.5 to about 5, an amount of Li2O in the range of about 2 to about 10, an amount of Na2O in the range of about 0 to about 6, an amount of MgO in the range of about 1 to about 4, an amount of ZnO in the range of about 0 to about 3, and an amount of CaO in the range of about 0 to about 5, the glass substrate is ion-exchangeable and is amorphous. In one or more embodiments, the glass substrate exhibits any one or more of a ratio of Li2O to R2O in the range of about 0.45 to about 1; a difference between the total amount of R2O and the amount of Al2O3 in the range of about -5 to about 0; a difference between the total amount of RxO (mole %) and the amount of Al2O3 in the range of about 0 to about 3; and a ratio of the amount of MgO (mole %) to the total amount of RO (mole %), in the range of about 0 to about 1, and the glass substrate is substantially free of nucleating agents.

[0022] The eighth aspect of the present disclosure relates to a glass substrate comprising a composition comprising, in mole %, an amount of SiO2 in the range of about 68 to about 75, an amount of Al2O3 in the range of about 12 to about 15, an amount of B2O3 in the range of about 0.5 to about 5, an amount of Li2O in the range of about 2 to about 10, an amount of Na2O in the range of about 0 to about 6, an amount of MgO in the range of about 1 to about 4, an amount of ZnO in the range of about 0 to about 3, and an amount of CaO in the range of about 0 to about 5, the glass substrate is ion-exchangeable and is amorphous. In one or more embodiments, the glass substrate exhibits any one or more of a ratio of Li2O to R2O in the range of about 0.45 to about 1; a difference between the total amount of R2O and the amount of Al2O3 in the range of about -5 to about 0; a difference between the total amount of RxO (mole %) and the amount of Al2O3 in the range of about 0 to about 3; and a ratio of the amount of MgO (mole %) to the total amount of RO (mole %), in the range of about 0 to about 1. In one or more embodiments, the glass substrate is substantially free of nucleating agents. A ninth aspect of the present disclosure relates to a glass substrate comprising, in mole %, an amount of SiO2 in the range of about 68 to about 75, an amount of Al2O3 in the range of about 12 to about 15, an amount of B2O3 in the range of about 0.5 to about 5, an amount of Li2O in the range of about 2 to about 10, an amount of Na2O in the range of about 0 to about 6, an amount of MgO in the range of about 1 to about 4, an amount of ZnO in the range of about 0 to about 3, and an amount of CaO in the range of about 0 to about 5, the glass substrate being amorphous and strengthened. In one or more embodiments, the Na2O concentration varies within the glass substrate. In one or more embodiments, the glass substrate is substantially free of nucleating agents. According to one or more embodiments, the strengthened glass substrate exhibits any one or more of the following compositional relationships: namely, the ratio of Li2O to R2O in the range of about 0.45 to about 1, the difference between the total amount of R2O and the amount of Al2O3 in the range of about -5 to about 0, the difference between the total amount of RxO (mole %) and the amount of Al2O3 in the range of about 0 to about 3, and the ratio of the amount of MgO (mole %) to the total amount of RO (mole %) in the range of about 0 to about 1.

[0023] A tenth aspect of the present disclosure is a housing having a front surface, a back surface, and side surfaces, electrical components at least partially inside the housing, a display at or near the front surface of the housing, and a cover substrate disposed on the display, the cover substrate comprising a glass-based article according to the embodiments described herein, related to a device.

[0024] Further features and advantages are described in the following detailed description, some of which will be readily apparent to those skilled in the art from that description, and will be recognized by practicing the embodiments described herein, which include the following detailed description, the claims, and the accompanying drawings.

[0025] It should be understood that the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of the claims. The accompanying drawings are included to provide a further understanding and are incorporated herein and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operations of the various embodiments.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0027] Here, various embodiments are referred to in detail, and examples thereof are described in the accompanying examples and drawings.

[0028] In the following description, like reference numerals refer to like or corresponding parts throughout several views shown in the drawings. Unless otherwise specified, it is understood that terms such as "upper", "lower", "outward", "inward", etc. are for convenience only and should not be construed as limiting terms. Further, whenever a group is described as including at least one of a group of elements and combinations thereof, the group includes, consists essentially of, or can be composed of any number of those recited elements, individually or in combination with each other. Similarly, whenever a group is described as consisting of at least one of a group of elements or combinations thereof, it is understood that the group can be composed of any number of the recited elements, individually or in combination with each other. Unless otherwise specified, when recited, a range of values includes both the upper and lower limits of the range, as well as any range therebetween. As used herein, unless otherwise specified, nouns refer to objects of "at least one" or "one or more than two". Also, it is understood that the various features disclosed in this specification and the drawings can be used in any and all combinations.

[0029] As used herein, the terms "glass article" and "glass substrate" are used in their broadest sense to include any object that is wholly or partially made of glass. Glass articles include laminates of glass and non-glass materials, laminates of glass and crystalline materials, and glass-ceramics (including amorphous and crystalline phases). Unless otherwise specified, all compositions are expressed in mole percent (mol%).

[0030] Note that the terms "substantially" and "about" can be used herein to represent the inherent degree of uncertainty that can result from any quantitative comparison, value, measurement, or other representation. These terms are also used herein to represent the degree to which a quantitative representation can differ from a reference described without causing a change in the basic function of the subject matter in question.

[0031] As used herein, the term "about" means that a quantity, dimension, composition, parameter, and other quantities and characteristics are not exact and need not be exact, but may be approximate and / or larger or smaller, and in some cases, may include tolerances, conversion factors, rounding, measurement errors, etc., and other factors known to those skilled in the art. When the term "about" is used to describe a value or endpoint of a range, the disclosure is to be understood as including the particular value or endpoint recited. Whether or not a numerical value or endpoint in the specification suggests "about", the numerical value or endpoint of the range is intended to include two embodiments, namely, those modified by "about" and those not modified by "about". Further, it will be further understood that each endpoint of each range is important both in relation to the other endpoint and independently of the other endpoint.

[0032] Unless otherwise specified, all temperatures are expressed in degrees Celsius (°C). As used herein, the term "softening point" refers to the temperature at which the viscosity of the glass is about 107.6 poises (P), the term "annealing point" refers to the temperature at which the viscosity of the glass is about 1013.2 poises, the term "200 poise temperature (T200P)" refers to the temperature at which the viscosity of the glass is about 200 poises, the term "1011 poise temperature" refers to the temperature at which the viscosity of the glass is about 1011 poises, the term "35 kP temperature (T35kP)" refers to the temperature at which the viscosity of the glass is about 35 kilopoises (kP), and the term "160 kP temperature (T160kP)" refers to the temperature at which the viscosity of the glass is about 160 kP.

[0033] Referring generally to the drawings, and particularly to FIGS. 1 - 3, it will be understood that the drawings are for the purpose of illustrating particular embodiments and are not intended to limit the disclosure or the appended claims. The drawings are not necessarily to scale, and particular features of the drawings and particular figures are shown exaggerated or schematically for clarity and simplicity.

[0034] As used herein, DOC refers to the depth at which the stress in a glass article changes from compressive stress to tensile stress. In DOC, the stress crosses from positive (compressive) stress to negative (tensile) stress (e.g., 130 in FIG. 1), and thus indicates a stress value of zero.

[0035] As used herein, the terms "chemical depth", "chemical depth of a layer", and "chemical layer depth" can be used interchangeably and refer to the depth to which ions of metal oxides or alkali metal oxides (e.g., metal ions or alkali metal ions), as determined by electron probe microanalysis (EPMA) or glow discharge - optical emission spectroscopy (GD - OES), diffuse into a glass article, and the depth at which the concentration of the ions reaches a minimum value. In particular, for evaluating the depth of diffusion of Na2O or the concentration of Na+ ions, it can be measured using EPMA and a surface stress meter (described in more detail below).

[0036] According to the convention commonly used in the art, unless otherwise specified, compression is represented as a negative (<0) stress and tension is represented as a positive (>0) stress. However, throughout this specification, when referring to compressive stress CS, it is mentioned regardless of whether the value is positive or negative, i.e., as described in this specification, CS = |CS|.

[0037] This specification describes thin chemically strengthened glass articles including glasses and glass - ceramics, such as silicate glasses containing alkali - containing glass, which can be used as cover glasses for portable electronic devices and touch - enabled displays. The glass articles can also be used for displays (or display articles) (e.g., signboards, point - of - sale management systems, computers, navigation systems, etc.), architectural articles (walls, fixtures, panels, windows, etc.), transportation articles (e.g., automotive applications, trains, airplanes, ships, etc.), electrical appliances (e.g., washing machines, dryers, dishwashers, refrigerators, etc.) or any article that requires a certain degree of fracture resistance. In particular, the glass articles described herein are thin but exhibit a stress profile that can only be achieved by annealing a thick glass article (e.g., having a thickness of about 2 mm or 3 mm or more). The glass articles exhibit a unique stress profile along their thickness. In some cases, the glass articles described herein exhibit a greater surface CS than the annealed glass articles. In one or more embodiments, the glass articles have a compressive stress layer that extends deeply and widely within the glass article, where the CS decreases and increases more gently than in known chemically strengthened glass articles, such that the glass article or a device containing it exhibits substantially improved fracture resistance even when dropped on a hard surface (e.g., granite) or a hard and rough surface (e.g., asphalt). The glass articles of one or more embodiments exhibit a greater maximum CT value than some known chemically strengthened glass substrates.

[0038] CS and the depth of penetration of potassium ions ("potassium DOL") are measured using means known in the art. Potassium DOL is distinguished from DOC as it represents the depth of potassium penetration as a result of the ion exchange process. Potassium DOL is generally less than DOC for the articles described herein. CS and potassium DOL are measured by a surface stress meter (FSM) using commercially available equipment such as the FSM-6000 manufactured by Orihara Industries Co., Ltd. (Japan). Surface stress measurements rely on accurate measurement of the stress-optic coefficient (SOC) related to the birefringence of the glass. The SOC is then measured according to a modified version of Procedure C described in ASTM standard C770-98(2013) entitled "Standard Test Method for Measurement of the Stress-Optic Coefficient of Glass", the contents of which are hereby incorporated by reference in their entirety. This modification includes using a glass disk as a test piece with a thickness of 5 - 10 mm and a diameter of 12.7 mm, the disk being isotropic, homogeneous, centrally perforated and ground on both sides to be parallel. The modification also includes calculating the maximum force Fmax to be applied. This force must be large enough to generate a compressive stress of 20 MPa or more. Fmax is calculated as follows.

[0039] Fmax = 7.854 * D * h Wherein Fmax = Force in Newton units D = Diameter of the disk h = Thickness of the optical path For each applied force, the stress is calculated as follows.

[0040] σMPa = 8F / (π * D * h) Wherein F = Force in Newton units D = Diameter of the disk h = Thickness of the optical path.

[0041] The DOC and the maximum CT value are measured using a scattered light polarimeter (SCALP) technique known in the art. The stress profile can be measured using the refractive near-field (RNF) method or SCALP. When the RNF method is utilized, the maximum CT value provided by the SCALP is used. In particular, the stress profile measured by the RNF is balanced in force and calibrated to the maximum CT value provided by the SCALP measurement. The RNF method is described in U.S. Patent No. 8,854,623, entitled "Systems and Methods for Measuring Profile Characteristics of a Glass Sample," which is hereby incorporated by reference in its entirety. Specifically, the RNF method includes placing a glass-based article adjacent to a reference block, generating a polarization-switching light beam that is switched between orthogonal polarizations at a speed between 1 Hz and 50 Hz, measuring the amount of force in the polarization-switching light beam, generating a polarization-switching reference signal, and the measured amount of force in each of the orthogonal polarizations is within 50% of each other. This method further includes transmitting the polarization-switching light beam through the glass sample and the reference block to different depths of the glass sample, and then using a relay optical system to relay the transmitted polarization-switching light beam to a signal light detector, where the signal light detector generates a polarization-switching detector signal. This method also includes dividing the detector signal by the reference signal to form a normalized detector signal and determining the profile characteristics of the glass sample from the normalized detector signal. The RNF profile is then smoothed and used in the CT region. As described above, the FSM technique is used for the surface CS and the slope of the stress profile in the CS region near the surface.

[0042] As described above, the glassy article described herein is chemically strengthened by ion exchange and exhibits a stress profile that is distinct from that exhibited by known strengthened glass articles. In this disclosure, the glassy substrate is typically not strengthened, and the glassy article generally refers to a glassy substrate that has been strengthened (e.g., by ion exchange). In this process, ions at or near the surface of the glassy article are replaced or exchanged by larger ions having the same valence or oxidation state. In embodiments where the glassy article comprises an alkali aluminosilicate glass, the ions in the surface layer of the glass and the larger ions are monovalent alkali metal cations, such as Li+ (when present in the glassy article), Na+, K+, Rb+ and Cs+. Alternatively, the monovalent cations in the surface layer may be replaced by monovalent cations other than alkali metal cations such as Ag+. In such embodiments, the monovalent ions (or cations) exchanged in the glassy substrate generate stress in the resulting glassy article.

[0043] The ion exchange process is typically carried out by immersing a glass-based substrate in a molten salt bath (or two or more molten salt baths) containing larger ions that are exchanged for smaller ions in the glass-based substrate. It should be noted that aqueous salt baths can also be used. Further, the bath composition can include two or more types of larger ions (e.g., Na+ and K+) or a single larger ion. One skilled in the art will understand that, without limitation, the parameters of the ion exchange process, including the bath composition and temperature, immersion time, number of immersions of the glass-based article into the salt bath (or baths), use of multiple salt baths, and additional steps such as annealing, cleaning, etc., are generally determined by the composition of the glass-based article (including the structure of the article and the crystalline phases present) and the desired DOC and CS of the glass-based article resulting from strengthening. By way of example, ion exchange of a glass-based substrate can be achieved by immersing the glass-based substrate in at least one molten bath containing salts such as nitrates, sulfates, and chlorides of larger alkali metal ions, without limitation. Typical nitrates include KNO3, NaNO3, LiNO3, NaSO4, and combinations thereof. The temperature of the molten salt bath is typically in the range of about 380 °C to about 450 °C, and the immersion time ranges from about 15 minutes to about 100 hours depending on the glass thickness, bath temperature, and glass (or monovalent ion) diffusivity. However, different temperatures and immersion times than those described above can also be used.

[0044] In one or more embodiments, the glass-based substrate may be immersed in a molten salt bath of 100% NaNO3 having a temperature of about 370 °C to about 480 °C. In some embodiments, the glass-based substrate may be immersed in a molten mixed salt bath containing about 5% to about 90% KNO3 and about 10% to about 95% NaNO3. In some embodiments, the glass-based substrate may be immersed in a molten mixed salt bath containing Na2SO4 and NaNO3 having a wider temperature range (e.g., up to about 500 °C). In one or more embodiments, the glass-based article may be immersed in a second bath after being immersed in the first bath. Immersion in the second bath may include immersing in a molten salt bath containing 100% KNO3 for 15 minutes to 8 hours.

[0045] In one or more embodiments, the glass-based substrate can be immersed in a molten mixed salt bath containing NaNO3 and KNO3 (e.g., 49% / 51%, 50% / 50%, 51% / 49%) having a temperature of less than about 420 °C (e.g., about 400 °C or about 380 °C) for less than about 5 hours, or within about 4 hours.

[0046] The ion exchange conditions can be adjusted to result in a "spike" or to increase the slope of the stress profile near or at the surface of the resulting glass-based article. This spike can be achieved by a single bath or multiple baths having a single composition or a mixed composition due to the unique properties of the glass composition used in the glass-based articles described herein.

[0047] As shown in FIG. 3, a glass article 300 of one or more embodiments includes a first surface 302 and a second surface 304 opposite the first surface, which define a thickness t. In one or more embodiments, the thickness t may be about 3 millimeters or less (e.g., in the range of about 0.01 millimeter to about 3 millimeters, about 0.1 millimeter to about 3 millimeters, about 0.2 millimeter to about 3 millimeters, about 0.3 millimeter to about 3 millimeters, about 0.4 millimeter to about 3 millimeters, about 0.01 millimeter to about 2.5 millimeters, about 0.01 millimeter to about 2 millimeters, about 0.01 millimeter to about 1.5 millimeters, about 0.01 millimeter to about 1 millimeter, about 0.01 millimeter to about 0.9 millimeter, about 0.01 millimeter to about 0.8 millimeter, about 0.01 millimeter to about 0.7 millimeter, about 0.01 millimeter to about 0.6 millimeter, about 0.01 millimeter to about 0.5 millimeter, about 0.1 millimeter to about 0.5 millimeter, or about 0.3 millimeter to about 0.5 millimeter).

[0048] The glass article includes a stress profile that extends from the first surface 302 to the second surface 304 (or along the entire length of the thickness t). In the embodiment shown in FIG. 3, the stress profile 312. The y-axis represents the stress value and the x-axis represents the thickness or depth of the glass article.

[0049] As shown in FIG. 3, the stress profile 312 includes a CS layer 315 (having a surface CS 310), a CT layer 325 (having a maximum CT 320), and a DOC 330, where the stress profile 312 changes from compression to tension. The CS layer has an associated depth or length 317 that extends from the surfaces 302, 304 to the DOC 330. The CT layer 325 also has an associated depth or length 327 (CT region or layer).

[0050] The surface CS310 may be about 150 MPa or more, or about 200 MPa or more (e.g., about 250 MPa or more, about 300 MPa or more, about 400 MPa or more, about 450 MPa or more, about 500 MPa or more, or about 550 MPa or more). The surface CS310 may be up to about 900 MPa, up to about 1000 MPa, up to about 1100 MPa, or up to about 1200 MPa. The surface CS value herein may include the maximum CS. In some embodiments, the surface CS is less than the maximum CS.

[0051] The maximum CT320 may be about 71.5 / √(t) or more. In some embodiments, the maximum CT320 is about 80 MPa or more, about 85 MPa or more, or about 90 MPa or more. In some embodiments, the maximum CT320 may be in the range of about 80 MPa to about 100 MPa (e.g., about 85 MPa to about 100 MPa, about 90 MPa to about 100 MPa, about 80 MPa to about 95 MPa, about 80 MPa to about 90 MPa, about 85 MPa to about 95 MPa, or about 88 MPa to about 92 MPa). The maximum CT320 may be located in the range of about 0.3·t to about 0.7·t, about 0.4·t to about 0.6·t, about 0.45·t to about 0.55·t. It should be noted that either one or more of the surface CS310 and the maximum CT320 may depend on the thickness of the glass article. For example, a glass article having a thickness of about 0.8 mm can have a maximum CT in the range of about 85 MPa to about 100 MPa. As the thickness of the glass article decreases, the maximum CT value may increase. In other words, the maximum CT value increases as the thickness decreases (or the glass article becomes thinner).

[0052] In some embodiments, the ratio of the maximum CT320 to the surface CS310 is in the range of about 0.1 to about 0.8 (e.g., in the range of about 0.1 to about 0.7, about 0.1 to about 0.6, about 0.1 to about 0.5, about 0.1 to about 0.4, about 0.1 to about 0.3, about 0.1 to about 0.25, about 0.1 to about 0.2, about 0.15 to about 0.8, about 0.2 to about 0.8, about 0.3 to about 0.8, about 0.4 to about 0.8, about 0.5 to about 0.8, or about 0.6 to about 0.8). In known chemically strengthened glass articles, the ratio of the maximum CT320 to the surface CS310 is 0.1 or less. In some embodiments, the surface CS can be 4 times (e.g., 5 times, 6 times or 6.5 times) or more of the maximum CT. In some embodiments, the surface CS can be up to about 47.5 times of the maximum CT. The surface CS can be in the range of about 4 times to about 7.5 times of the maximum CT.

[0053] In one or more embodiments, the stress profile 312 includes a maximum CS, which is typically the surface CS310 and can be seen at one or both of the first surface 302 and the second surface 304. In one or more embodiments, the CS layer or region 315 extends along a portion of the thickness 317 to the DOC330 and the maximum CT320. In one or more embodiments, the DOC330 can be about 0.1·t or more. For example, the DOC330 can be about 0.12·t or more, about 0.14·t or more, about 0.15·t or more, about 0.16·t or more, 0.17·t or more, 0.18·t or more, 0.19·t or more, 0.20·t or more, about 0.21·t or more, or up to about 0.25·t. In some embodiments, the DOC330 is less than the chemical depth. The chemical depth can be about 0.4·t or more, 0.5·t or more, about 0.55·t or more, or about 0.6·t or more.

[0054] In one or more embodiments, the glass article has a potassium DOL in the range of about 6 micrometers to about 20 micrometers. In some embodiments, the potassium DOL can be expressed as a function of the thickness t of the glass article. In one or more embodiments, the potassium DOL can be in the range of about 0.005·t to about 0.05·t. In some embodiments, the potassium DOL can be in the range of about 0.005·t to about 0.05·t, about 0.005·t to about 0.045·t, about 0.005·t to about 0.04·t, about 0.005·t to about 0.035·t, about 0.005·t to about 0.03·t, about 0.005·t to about 0.025·t, about 0.005·t to about 0.02·t, about 0.005·t to about 0.015·t, about 0.005·t to about 0.01·t, about 0.006·t to about 0.05·t, about 0.008·t to about 0.05·t, about 0.01·t to about 0.05·t, about 0.015·t to about 0.05·t, about 0.02·t to about 0.05·t, about 0.025·t to about 0.05·t, about 0.03·t to about 0.05·t or about 0.01·t to about 0.02·t.

[0055] In one or more embodiments, the compressive stress value at the potassium DOL depth can be in the range of about 50 MPa to about 300 MPa. In some embodiments, the compressive stress value at the potassium DOL depth can be in the range of about 50 MPa to about 280 MPa, about 50 MPa to about 260 MPa, about 50 MPa to about 250 MPa, about 50 MPa to about 240 MPa, about 50 MPa to about 220 MPa, about 50 MPa to about 200 MPa, about 60 MPa to about 300 MPa, about 70 MPa to about 300 MPa, about 75 MPa to about 300 MPa, about 80 MPa to about 300 MPa, about 90 MPa to about 300 MPa, about 100 MPa to about 300 MPa, about 110 MPa to about 300 MPa, about 120 MPa to about 300 MPa, about 130 MPa to about 300 MPa or about 150 MPa to about 300 MPa.

[0056] In one or more embodiments, the stress profile 312 can be described as having a parabolic shape. In some embodiments, the stress profile along the region or depth of the glassy article exhibiting tensile stress exhibits a parabolic shape. In one or more particular embodiments, the stress profile 312 does not include a flat stress (either compressive or tensile) portion or a portion exhibiting substantially constant stress (either compressive or tensile). In some embodiments, the CT region exhibits a stress profile that is substantially free of flat stress or has no substantially constant stress. In one or more embodiments, all points of the stress profile 312 between the thickness ranges of about 0·t to about 0.2·t and beyond 0.8·t (or, about 0·t to about 0.3·t and about 0.7·t to t) include a tangent having an absolute value of slope greater than about 0.1 MPa / micrometer. In some embodiments, the slope of the tangent can have an absolute value greater than about 0.2 MPa / micrometer. In some more specific embodiments, the slope of the tangent can have an absolute value greater than about 0.3 MPa / micrometer. In even more specific embodiments, the slope of the tangent can have an absolute value greater than about 0.5 MPa / micrometer. In other words, the stress profiles of one or more embodiments along these thickness ranges (i.e., up to about 0.2·t and beyond 0.8·t, or, 0·t to about 0.3·t and about 0.7·t and above) exclude points having a tangent with a slope of zero, a slope that is nearly zero, or a flat slope. Without being bound by theory, known error functions or quasi-linear stress profiles can have a tangent with a slope that is zero or close to zero, i.e., can have an absolute value less than about 0.1 MPa / micrometer (as shown in FIG. 2,220, showing a flat or zero slope stress profile along such thickness ranges) and have points along these thickness ranges (i.e., up to about 0.2·t and beyond 0.8·t, or, 0·t to about 0.3·t and about 0.7·t and above).The glassy article of one or more embodiments of the present disclosure does not exhibit a stress profile having a flat or zero-slope stress profile along these thickness ranges, as shown in FIG. 3.

[0057] In one or more embodiments, the glassy article exhibits a stress profile within thickness ranges of about 0.1·t to 0.3·t and about 0.7·t to 0.9·t that includes a tangent having a maximum slope and a minimum slope. In some examples, the difference between the maximum slope and the minimum slope is about 3.5 MPa / micrometer or less, about 3 MPa / micrometer or less, about 2.5 MPa / micrometer or less, or about 2 MPa / micrometer or less.

[0058] In one or more embodiments, the glass article includes a stress profile 312 that does not substantially include any flat portions extending in the depth direction of the glass article or along at least a portion of the thickness t. In other words, the stress profile 312 increases or decreases substantially continuously along the thickness t. In some embodiments, the stress profile does not substantially include any flat portions in the depth direction having a length of about 10 micrometers or more, about 50 micrometers or more, or about 100 micrometers or more, or about 200 micrometers or more. As used herein, the term "flat" refers to an inclination having a magnitude of less than about 0.5 MPa / micrometer, or less than about 0.2 MPa / micrometer, along the flat portion. In some embodiments, one or more portions of the stress profile that do not substantially include any flat portions in the depth direction are present at a depth within the glass article of about 5 micrometers or more (e.g., 10 micrometers or more, or 15 micrometers or more) from one or both of the first surface or the second surface. For example, along the depth from about 0 micrometers to less than about 5 micrometers from the first surface, the stress profile may include a linear portion, but from a depth of about 5 micrometers or more from the first surface, the stress profile need not substantially include a flat portion. As used herein, "linear" includes line segments having a flat inclination and line segments not having a flat inclination. For example, in the latter case, see FIG. 33 within a depth of about 12 micrometers from the surface.

[0059] In some embodiments, the stress profile includes a linear portion at a depth from about 0·t to about 0.1·t and may not substantially include a flat portion at a depth from about 0.1·t to about 0.4·t. In some embodiments, the stress profile for a thickness within the range of about 0·t to about 0.1·t can have a slope with a magnitude (absolute value) within the range of about 20 MPa / micrometer to about 200 MPa / micrometer. As described herein, such embodiments can be formed using a single ion exchange process where the bath contains two or more alkali salts or is a mixed alkali salt bath, or multiple (e.g., two or more times) ion exchange processes.

[0060] In one or more embodiments, the glass article can be described by the shape of the stress profile (327 in FIG. 3) along the CT region. For example, in some embodiments, the stress profile (tensile stress) along the CT region can be approximated by an equation. In some embodiments, the stress profile along the CT region can be approximated by Equation (1): Stress(x) = MaxT - (((CTn · (n + 1)) / 0.5n) · |(x / t) - 0.5|n) (1) In Equation (1), stress (x) is the stress value at position x. Here, the stress is positive (tensile). In Equation (1), MaxT is the maximum tensile value, CTn is the tensile value at n, and CTn is less than or equal to MaxT. Both MaxT and CTn are positive values in MPa units. The value x is a position along the thickness (t) in micrometer units within the range of 0 to t, where x = 0 is one surface (302 in Figure 3), x = 0.5t is the center of the glass article (at that position, stress(x) = MaxT), and x = t is the opposite surface (304 in Figure 3). MaxT used in Equation (1) is equivalent to the maximum CT and can be about 71.5 / √(t) or more. In some embodiments, MaxT used in Equation (1) can be in the range of greater than about 80 MPa to about 100 MPa (e.g., about 85 MPa to about 100 MPa, about 90 MPa to about 100 MPa, greater than about 80 MPa to about 95 MPa, greater than about 80 MPa to about 90 MPa, or about 85 MPa to about 95 MPa), and n is a fitting parameter of 1.5 to 5 (e.g., 2 to 4, 2 to 3, or 1.8 to 2.2) or about 1.5 to about 2. In one or more embodiments, n = 2 can provide a parabolic stress profile, and the exponent resulting from n = 2 provides a stress profile close to a parabolic stress profile. Figure 4 is a graph showing various stress profiles according to one or more embodiments of the present disclosure based on changes in the fitting parameter n.

[0061] In one or more embodiments, CTn may be less than MaxT, in which case there are compressive stress spikes on one or both of the major surfaces of the glass article. In one or more embodiments, CTn is equal to MaxT, in which case there are no compressive stress spikes on one or both of the major surfaces of the glass article.

[0062] In some embodiments, the stress profile may be modified by heat treatment. In such embodiments, the heat treatment can be performed before, during, or after any ion exchange process. In some embodiments, the heat treatment can reduce the absolute value of the magnitude of the slope of the stress profile at or near the surface. In some embodiments where a steeper or larger slope is desired at the surface, an ion exchange process after the heat treatment can be utilized to provide a "spike" or increase the slope of the stress profile at or near the surface.

[0063] In one or more embodiments, a stress profile 312 is generated due to a non-zero concentration of metal oxide(s) that varies along a portion of the thickness. As described above, the variation in the metal oxide concentration can be referred to herein as a metal oxide concentration gradient. In some embodiments, the concentration of the metal oxide is non-zero and varies along a thickness range from about 0·t to about 0.3·t. In some embodiments, the concentration of the metal oxide is non-zero and varies along a thickness range from about 0·t to about 0.35·t, from about 0·t to about 0.4·t, from about 0·t to about 0.45·t, or from about 0·t to about 0.48·t. The metal oxide can be described as generating stress within the glassy article. The variation in concentration can be continuous along the above-described thickness range. The variation in concentration can include a change in the metal oxide concentration of about 0.2 mol% along a thickness portion of about 100 micrometers. This change can be measured by known methods in the art including microprobes, as shown in Example 1. The metal oxide with a non-zero concentration that varies along a portion of the thickness can be described as generating stress within the glassy article.

[0064] The change in concentration may be continuous along the above-described thickness range. In some embodiments, the change in concentration can be continuous along a thickness portion in the range of about 10 micrometers to about 30 micrometers. In some embodiments, the concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface and increases from that value to the second surface.

[0065] The concentration of the metal oxide can include two or more metal oxides (e.g., a combination of Na2O and K2O). In some embodiments where two metal oxides are used and the ionic radii are different from each other, at a shallow depth, the concentration of ions with a larger radius is greater than the concentration of ions with a smaller radius, but at a deeper depth, the concentration of ions with a smaller radius is greater than the concentration of ions with a larger radius. For example, when a single Na- and K-containing bath is used in an ion exchange process, at a shallow depth, the concentration of K+ ions in the glass article is greater than the concentration of Na+ ions, and at a deeper depth, the concentration of Na+ ions is greater than the concentration of K+ ions. This is due in part to the dimensions of the monovalent ions that are exchanged into the glass in place of smaller monovalent ions. In such a glass article, the surface or the region near it will have a greater CS due to a larger amount of larger ions (i.e., K+ ions) at or near the surface. This greater CS can be indicated by a stress profile having a steeper slope at or near the surface (i.e., a spike in the stress profile at the surface).

[0066] A concentration gradient or change of one or more metal oxides is created by chemically strengthening a glass-based substrate as previously described herein to exchange a plurality of first metal ions in the glass-based substrate for a plurality of second metal ions. The first ions may be ions of lithium, sodium, potassium, and rubidium. The second metal ion may be one ion of sodium, potassium, rubidium, and cesium, but the second alkali metal ion has an ionic radius larger than the ionic radius of the first alkali metal ion. The second metal ion is present in the glass-based substrate as its oxide (e.g., Na2O, K2O, Rb2O, Cs2O, or a combination thereof).

[0067] In one or more embodiments, the metal oxide concentration gradient extends across a substantial portion or the entire thickness t of the glass-based article, including the CT layer 327. In one or more embodiments, the concentration of the metal oxide is about 0.5 mol% or more in the CT layer 327. In some embodiments, the concentration of the metal oxide may be about 0.5 mol% or more (e.g., about 1 mol% or more) across the entire thickness of the glass-based article, reaching a maximum at the first surface 302 and / or the second surface 304 and decreasing at a substantially constant rate to a value at a point between the first surface 302 and the second surface 304. At that point, the concentration of the metal oxide is the lowest along the entire thickness t, but the concentration is not zero at that point. In other words, the non-zero concentration of that particular metal oxide extends across a substantial portion or the entire thickness t (described herein). In some embodiments, the concentration in a particular metal oxide is the lowest in the CT layer 327. The total concentration of a particular metal oxide in the glass-based article can range from about 1 mol% to about 20 mol%.

[0068] In one or more embodiments, the glass article includes a first metal oxide concentration and a second metal oxide concentration, the first metal oxide concentration being in the range of about 0 mol% to about 15 mol% along a first thickness range of about 0·t to about 0.5t, the second metal oxide concentration being in the range of about 0 mol% to about 10 mol% from a second thickness range of about 0 micrometers to about 25 micrometers (or about 0 micrometers to about 12 micrometers), but the concentration of one or both of the first metal oxide and the second metal oxide is non-zero along the entire thickness or a substantial portion of the glass article. The glass article can include any third metal oxide concentration. The first metal oxide can include Na2O, and the second metal oxide can include K2O.

[0069] The concentration of the metal oxide can be determined from a reference amount of the metal oxide in the glass article before being modified to have such a concentration gradient of the metal oxide.

[0070] In one or more embodiments, the glass article can be described in terms of how it breaks and the fragments resulting from such breakage, as measured by the "fragility test" described in Z. Tang et al., Automated Apparatus for Measuring the Frangibility and Fragmentation of Strengthened Glass. Experimental Mechanics (2014) 54:903 - 912. In one or more embodiments, when broken, the glass article breaks into two or more fragments per square inch (or per 6.4516 square centimeters) of the glass article (before breakage). In some cases, the glass article breaks into three or more, four or more, five or more, or ten or more fragments per square inch (or per 6.4516 square centimeters) of the glass article (before breakage). In some examples, when broken, the glass article breaks into fragments such that more than 50% of the fragments have a surface area of less than 5%, less than 2%, or less than 1% of the surface area of the glass article (before breakage), and the sample dimensions used were 5.08 cm × 5.08 cm (2 inches × 2 inches) square. In one embodiment, when broken, the glass article breaks into fragments such that 90% or more or 100% of the fragments have a surface area of less than 5%, less than 2%, or less than 1% of the surface area of the glass article (before breakage).

[0071] In one or more embodiments, after chemically strengthening a glass article, the resulting stress profile 312 of the glass article provides improved fracture resistance. For example, in some embodiments, when broken, the glass article has fragments with an average longest cross-sectional dimension of about 2·t or less (e.g., 1.8·t, 1.6·t, 1.5·t, 1.4·t, 1.2·t, or 1·t or less) as measured by the "fragility test" described in Z. Tang et al., Automated Apparatus for Measuring the Frangibility and Fragmentation of Strengthened Glass. Experimental Mechanics (2014) 54:903-912. The number of fragments is divided by the area (square inches) of the sample being tested, and the sample dimensions used were 5.08 cm × 5.08 cm (2 inches × 2 inches) square.

[0072] In one or more embodiments, the glass article can exhibit a fracture toughness (K1C) of about 0.65 MPa·m 1 / 2 or greater. In some cases, the fracture toughness is about 0.69 MPa·m 1 / 2 or greater, about 0.7 MPa·m 1 / 2 or greater, about 0.8 MPa·m 1 / 2 or greater, or about 0.9 MPa·m 1 / 2 or greater. In some embodiments, the fracture toughness is about 0.65 MPa·m 1 / 2 to about 1 MPa·m 1 / 2It may also be within the range. The fracture toughness value (K1C) cited in the present disclosure refers to the value measured by the chevron-notched short bar (CNSB) method disclosed in Reddy, K.P.R. et al, “Fracture Toughness Measurement of Glass and Ceramic Materials Using Chevron-Notched Specimens,” J. Am. Ceram. Soc., 71 [6], C-310-C-313 (1988), provided that Y*m is calculated using Equation 5 of Bubsey, R.T. et al., “Closed-Form Expressions for Crack-Mouth Displacement and Stress Intensity Factors for Chevron-Notched Short Bar and Short Rod Specimens Based on Experimental Compliance Measurements,” NASA Technical Memorandum 83796, pp. 1-30 (October 1992).

[0073] In some embodiments, the substrate can also be characterized as having a hardness of about 500 HVN to about 800 HVN (kgf / mm 2 ) as measured by a Vickers hardness test with a 200 g load. In some embodiments, the glass article can include a Vickers hardness within the range of about 600 HVN to about 800 HVN.

[0074] The glass article described herein can exhibit a stored tensile energy in the range of 0 J / m 2 to about 40 J / m 2 . In some cases, the stored tensile energy is about 5 J / m 2 to about 40 J / m 2 , about 10 J / m 2 to about 40 J / m 2 , about 15 J / m 2 to about 40 J / m 2 , about 20 J / m2 ~ about 40 J / m 2 、 about 1 J / m 2 ~ about 35 J / m 2 、 about 1 J / m 2 ~ about 30 J / m 2 、 about 1 J / m 2 ~ about 25 J / m 2 、 about 1 J / m 2 ~ about 20 J / m 2 、 about 1 J / m 2 ~ about 15 J / m 2 、 about 1 J / m 2 ~ about 10 J / m 2 、 about 10 J / m 2 ~ about 30 J / m 2 、 about 10 J / m 2 ~ about 25 J / m 2 、 about 15 J / m 2 ~ about 30 J / m 2 、 about 15 J / m 2 ~ about 25 J / m 2 、 about 18 J / m 2 ~ about 22 J / m 2 、 about 25 J / m 2 ~ about 40 J / m 2 or about 25 J / m 2 ~ about 30 J / m 2 may be within the range of. The thermally and chemically strengthened glass articles of one or more embodiments are about 6 J / m 2 or more, about 10 J / m 2 or more, about 15 J / m 2 or more or about 20 J / m 2 or more can exhibit a stored tensile energy.

[0075] The stored tensile energy can be calculated using the following formula (2).

[0076] Stored tensile energy (J / m 2 ) = [(1 - ν) / E] ∫(σ^2)(dt) (2) In the formula, ν is the Poisson's ratio, E is the Young's modulus (MPa), and σ is the stress (MPa), and the integral is calculated over the thickness (micrometers) of only the tensile region. Each of the Young's modulus values cited in the present disclosure refers to a value measured by a general type of resonant ultrasonic spectroscopy technique described in ASTM E2001-13 entitled "Standard Guide for Resonant Ultrasonic Spectroscopy for Defect Detection in Both Metallic and Nonmetallic Parts".

[0077] The glass articles described herein typically have a Young's modulus in the range of about 70 GPa or more (e.g., about 70 GPa to about 100 GPa, about 72 GPa to about 100 GPa, about 75 GPa to about 100 GPa, about 76 GPa to about 100 GPa, about 78 GPa to about 100 GPa, about 80 GPa to about 100 GPa, about 82 GPa to about 100 GPa, about 84 GPa to about 100 GPa, about 86 GPa to about 100 GPa, about 88 GPa to about 100 GPa, about 90 GPa to about 100 GPa, about 70 GPa to about 95 GPa, about 70 GPa to about 90 GPa, about 70 GPa to about 88 GPa, about 70 GPa to about 86 GPa, about 70 GPa to about 85 GPa, about 70 GPa to about 84 GPa, about 70 GPa to about 82 GPa, or about 70 GPa to about 80 GPa). The Young's modulus inherent in the composition of the glass article can provide the desired high rigidity, which is an extrinsic property, for the final glass article produced therefrom.

[0078] In some embodiments, the glass article includes a low liquid-phase viscosity that enables the formation of the glass article via thin rolling techniques. As used herein, the term "liquid-phase viscosity" refers to the viscosity of the molten glass at the liquidus temperature, and the term "liquidus temperature" refers to the temperature at which crystals first appear as the molten glass cools from the melting temperature (or the temperature at which the last crystals melt as the temperature rises from room temperature). Generally, the glass articles described herein (or the compositions used to form such articles) have a liquid-phase viscosity of less than about 100 kilopoise (kP). In some embodiments, the glass article (or the composition used to form such article) exhibits a liquid-phase viscosity of less than about 80 kP, less than about 60 kP, less than about 40 kP, less than about 30 kP (e.g., within the range of about 15 kP to about 30 kP). The liquid-phase viscosity is determined by the following method. First, the liquidus temperature of the glass is measured in accordance with ASTM C829-81(2015), entitled "Standard Practice for Measurement of the Liquidus Temperature of Glass by the Gradient Furnace Method". Next, the viscosity of the glass at the liquidus temperature is measured in accordance with ASTM C965-96(2012), entitled "Standard Practice for Measuring the Viscosity of Glass Above the Softening Point".

[0079] In one or more embodiments, the glass article exhibits a Knoop lateral crack scratch threshold in the range of about 4 N to about 7 N, about 4.5 N to about 7 N, about 5 N to about 7 N, about 4 N to about 6.5 N, about 4 N to about 6 N, or about 5 N to about 6 N. As used herein, the Knoop scratch lateral crack threshold is the starting point of a lateral crack (in 3 or more out of 5 scratches). A series of increasing constant load scratches (at least 3 times per load, but the number of times per load can be increased to increase the confidence level) are performed to identify the Knoop scratch threshold. In the Knoop scratch lateral crack threshold test, for each load, a sample of the glass substrate and / or article is scratched with a Knoop indenter at a speed of 0.25 mm / s over a length of 10 mm. The Knoop scratch threshold range can be determined by comparing the test piece to one of the following three defect modes: 1) a continuous lateral crack that exceeds twice the width of the groove, 2) a lateral crack that is less than twice the width of the groove and contains damage within the groove, and there is visible damage to the naked eye, or 3) the presence of a large subsurface lateral crack that is greater than twice the width of the groove, and / or a central crack at the peak of the scratch. The scratch threshold is the highest load at which no defects occur in 3 or more out of 5.

[0080] In one or more embodiments, the glass article exhibits a Vickers indenter fracture threshold in the range of about 10 kgf or more, about 12 kgf or more, or about 15 kgf or more. In some cases, the glass article exhibits a Vickers indentation fracture threshold in the range of about 15 kgf to about 25 kgf. As used herein, the Vickers indentation fracture threshold is the starting point of a central / radial crack (in 3 or more out of 5 indentation events) that spreads from at least one corner of the indentation site. In the Vickers indentation fracture threshold test, samples of the glass substrate and article are repeatedly indented with a diamond tip (at an angle of 136°) while increasing the load. Each indentation can generate 4 radial cracks, one from each corner of the indentation. By counting the average number of radial cracks at each indentation load, the crack threshold is the load at which there are an average of 2 cracks per indentation (or a 50% crack threshold).

[0081] In one or more embodiments, the glass article exhibits improved surface strength when subjected to an Abrasion Ring-on-Ring (AROR) test. The strength of a material is the stress at which fracture occurs. The AROR test is a surface strength measurement for testing flat glass specimens, and ASTM C1499 - 09 (2013), entitled "Standard Test Method for Monotonic Equivalent Bending Strength of Advanced Ceramics at Ambient Temperature," serves as the basis for the AROR test methodology described herein. The content of ASTM C1499 - 09 is hereby incorporated by reference in its entirety. In one embodiment, the glass sample is abraded prior to the Ring-on-Ring test using the method and apparatus described in Annex A2, entitled "Abrasion Procedure," of ASTM C158 - 02 (2012), entitled "Standard Test Method for Strength of Glass by Bending (Determination of Modulus of Rupture)." The content of ASTM C158 - 02 and in particular the content of Annex 2 are hereby incorporated by reference in their entirety.

[0082] Prior to the Ring-on-Ring test, the surface of the glass article is abraded as described in ASTM C158 - 02, Annex 2, using the apparatus shown in Figure A2.1 of ASTM C158 - 02 to standardize and / or control the surface defect state of the sample. The abrasive is typically sandblasted onto the surface 110 of the glass article at a load of 15 psi using an air pressure of 304 kPa (44 psi), but in the following examples, the abrasive was sandblasted onto the surface 110 at other loads (e.g., 25 psi or 45 psi). After the air flow is established, 5 cm 3 of the abrasive is discarded into the funnel, and after introducing the abrasive, the sample is sandblasted for 5 seconds.

[0083] For the AROR test, a glass article having at least one wear surface 410 as shown in FIG. 5 was placed between two concentric rings of different sizes, also as shown in FIG. 5, to determine the equivalent flexural strength (i.e., the maximum stress that the material can withstand when subjected to bending between the two concentric rings). In the AROR configuration 400, the worn glass article 410 is supported by a support ring 420 having a diameter D2. The force F is applied to the surface of the glass article by a load cell (not shown) via a load ring 430 having a diameter D1.

[0084] The ratio D1 / D2 of the diameters of the load ring and the support ring can range from about 0.2 to about 0.5. In some embodiments, D1 / D2 is about 0.5. The load and support rings 130, 120 should be concentrically aligned within 0.5% of the support ring diameter D2. The load cell used in the test needs to be accurate within ±1% of the selected range for any load. In some embodiments, the test is performed at a temperature of 23 ± 2°C and a relative humidity of 40 ± 10%.

[0085] In the case of the fixture design, the radius r of the protruding surface of the load ring 430 is such that h / 2 ≤ r ≤ 3h / 2, where h is the thickness of the glass article 410. The load and support rings 430, 420 are typically made of hardened steel with a hardness HRc > 40. AROR fixtures are commercially available.

[0086] The intended defect mechanism of the AROR test is to observe the breakage of the glass article 410 starting from the surface 430a within the load ring 430. Defects occurring outside this region, i.e., between the load ring 430 and the support ring 420, are excluded from the data analysis. However, due to the thinness and high strength of the glass article 410, large deflections exceeding 1 / 2 of the specimen thickness h may be observed. Therefore, it is not uncommon to observe a high percentage of defects originating from below the load ring 430. Stress cannot be accurately calculated without knowing the stress generation (collected by strain gauge analysis) both inside and below the ring and the origin of the defects in each specimen. Therefore, the AROR test focuses on the peak load at the time of defect as the measured response.

[0087] The strength of a glass article depends on the presence of surface scratches. However, since the strength of glass is inherently statistical, the probability of having a scratch of a given size cannot be accurately predicted. Therefore, in general, a probability distribution can be used as a statistical representation of the obtained data.

[0088] In some embodiments, the glass article described herein has a surface or equivalent flexural strength of 20 kgf or more and up to about 30 kgf, as determined by an AROR test using a load of 25 psi or 45 psi to abrade the surface. In other embodiments, the surface strength is 25 kgf or more, and in still other embodiments, 30 kgf or more.

[0089] In some embodiments, the glass articles described herein can be described with respect to their performance in an Inverted Ball on Sandpaper (IBoS) test. The IBoS test is a dynamic component level test that mimics the main mechanisms of damage introduction and bending-induced defects typical of glass articles used in portable or handheld electronic devices, as schematically shown in FIG. 6. In the field, damage introduction (FIG. 7a) occurs on the upper surface of the glass article. Failure begins on the upper surface of the glass article and the damage penetrates the glass article (FIG. 7b), or failure proceeds from bending of the upper surface of the glass article or from the inner portion of the glass article (FIG. 7c). The IBoS test is designed to simultaneously damage the glass surface and apply bending under dynamic loading. In some examples, glass articles having compressive stress exhibit improved drop performance compared to the same glass articles not having compressive stress.

[0090] The IBoS test apparatus is schematically shown in FIG. 6. The apparatus 500 includes a test stand 510 and a ball 530. The ball 530 is a hard or solid ball, such as a stainless steel ball, for example. In one embodiment, the ball 530 is a 4.2 gram stainless steel ball with a diameter of 10 mm. The ball 530 is dropped directly onto the glass article sample 518 from a predetermined height h. The test stand 510 has a solid base 512 that includes a hard and rigid material such as granite. A sheet 514 with abrasive material disposed on its surface is placed on the upper surface of the solid base 512 such that the surface with the abrasive material faces upward. In some embodiments, the sheet 514 is sandpaper having a 30 grit surface, and in other embodiments, it is an 180 grit surface. The glass article sample 518 is held above the sheet 514 by a sample holder 515 such that there is a gap 516 between the glass article sample 518 and the sheet 514. The gap 516 between the sheet 514 and the glass article sample 518 allows the glass article sample 518 to bend and touch the worn surface of the sheet 514 when it is impacted by the ball 530. In one embodiment, all corners of the glass article sample 218 are clamped to maintain bending only at the point of ball impact to ensure reproducibility. In some embodiments, the sample holder 514 and the test stand 510 are adapted to accommodate a sample thickness of up to about 2 mm. The gap 516 is in the range of about 50 μm to about 100 μm. The gap 516 is adapted to adjust the difference in material rigidity (Young's modulus, Emod), although the Young's modulus and thickness of the sample are also included therein. An adhesive tape 520 can be used to cover the upper surface of the glass article sample to collect fragments in case the glass article sample 518 breaks upon impact of the ball 530.

[0091] A variety of materials can be used as the wear surface. In one particular embodiment, the wear surface is sandpaper such as silicon carbide or alumina sandpaper, processed sandpaper, or any abrasive known to those skilled in the art having equivalent hardness and / or sharpness. In some embodiments, 30 grit sandpaper can be used as it has a more consistent surface profile than either concrete or asphalt and has a particle size and sharpness that produces the desired level of damage to the sample surface.

[0092] In one aspect, a method 600 for performing an IBoS test using the apparatus 500 described above is shown in FIG. 8. In step 610, a glass article sample (218 in FIG. 6) is placed within the test stand 510 described above and secured to the sample holder 515 such that a gap 516 is formed between the glass article sample 518 and the sheet 514 having the wear surface. Method 600 assumes that the sheet 514 having the wear surface is already placed within the test stand 510. However, in some embodiments, it includes placing the sheet 514 within the test stand 510 such that the surface having the abrasive faces upward. In some embodiments (step 610a), an adhesive tape 520 is applied to the upper surface of the glass article sample 518 before securing the glass article sample 518 within the sample holder 510.

[0093] In step 520, a solid ball 530 of a predetermined mass and size is dropped from a predetermined height h onto the upper surface of the glass article sample 518 such that the ball 530 impacts the upper surface (or the adhesive tape 520 applied to the upper surface) at approximately the center of the upper surface (i.e., within 1 mm, or 3 mm, or 5 mm, or 10 mm from the center). After the impact is applied in step 520, the degree of damage to the glass article sample 518 is determined (step 630). As described above, in this specification, the term "breakage" means that cracks propagate across the entire thickness and / or surface of the substrate when the substrate is dropped or impacted by an object.

[0094] In method 600, in order to avoid the "aging" effect observed with repeated use of the drop test surface of other types (e.g., concrete or asphalt), the sheet 518 with a wear surface can be replaced after each drop.

[0095] Various predetermined drop heights h and increments are typically used in method 600. The test can utilize a minimum drop height (e.g., about 10 - 20 cm) to start, for example. Next, the height can be increased for successive drops either by a set increment or a variable increment. The test described in method 600 stops (step 631) when the glass - based article sample 518 breaks or fractures once. Alternatively, when the drop height h reaches a maximum drop height (e.g., about 100 cm) without breaking, the drop test of method 300 may be stopped, or step 520 may be repeated at the maximum height until breakage occurs.

[0096] In some embodiments, the IBoS test of method 600 is performed only once on each glass - based article sample 518 at each predetermined height h. However, in other embodiments, each sample can be subjected to multiple tests at each height.

[0097] When breakage of the glass - based article sample 518 occurs (step 631 in FIG. 8), the IBoS test according to method 600 is terminated (step 640). If no breakage is observed due to the drop of the ball at a predetermined drop height (step 632), the drop height is increased by a predetermined increment (step 634), e.g., 5, 10, 20 cm, etc., and steps 620 and 630 are repeated until sample breakage is observed (631) or the maximum test height is reached without sample breakage (636). When either step 631 or 636 is reached, the test according to method 600 is terminated.

[0098] When subjected to the aforementioned Inverted Ball on Sandpaper (IBoS) test, embodiments of the glassy article described herein have a survival rate of about 60% or more when the ball is dropped onto the surface of the glass from a height of 100 cm. For example, a glassy article is described as having a survival rate of 60% when dropped from a given height (here 100 cm) if 3 out of 5 identical (or nearly identical) samples (i.e., samples having substantially the same composition and, when strengthened, having substantially the same compressive stress and compressive depth, or a compressive stress layer as described herein) withstand the IBoS drop test without breaking when dropped from the given height. In other embodiments, the survival rate of a strengthened glassy article in the 80 cm IBoS test is about 70% or more, in other embodiments about 80% or more, and in still other embodiments about 90% or more. In other embodiments, the survival rate of a strengthened glassy article dropped from a height of 100 cm in the IBoS test is about 60% or more, in other embodiments about 70% or more, in still other embodiments about 80% or more, and in other embodiments about 90% or more. In one or more embodiments, the survival rate of a strengthened glassy article dropped from a height of 150 cm in the IBoS test is about 60% or more, in other embodiments about 70% or more, in still other embodiments about 80% or more, and in other embodiments about 90% or more.

[0099] In order to determine the survival rate of glass articles when dropped from a predetermined height using the above-described IBoS test method and apparatus, at least five identical (or substantially identical) samples of the glass article (i.e., having substantially the same composition and, when strengthened, having substantially the same compressive stress and depth or layer of compression) are tested, although a larger number (e.g., 10, 20, 30, etc.) of samples can be subjected to the test to increase the confidence level of the test results. Each sample is dropped once from a predetermined height (e.g., 100 cm or 150 cm) or dropped gradually from a higher height without breaking until it reaches the predetermined height, and visually (i.e., with the naked eye) inspected for evidence of breakage (formation and propagation of cracks across the entire thickness and / or surface of the sample). A sample is considered to "survive" the drop test if no breakage is observed after dropping from the predetermined height, and a sample is considered to be "defective" (or "not surviving") if breakage is observed when the sample is dropped from a height below the predetermined height. The survival rate is determined to be the percentage of the population of samples that survived the drop test. For example, if 7 out of 10 groups of samples did not break when dropped from the predetermined height, the survival rate of the glass is 70%.

[0100] The glass article described herein may be transparent. In one or more embodiments, the glass article can have a thickness of about 3 millimeters or less, e.g., a thickness of about 1 millimeter or less, and exhibit a transmittance of about 88% or more over a wavelength range of about 380 nm to about 780 nm.

[0101] The glass article can also exhibit a substantially white color. For example, the glass article can exhibit CIELAB color space coordinates under the CIE illuminant F02 with an L* value of about 88 or more, an a* value in the range of about -3 to about +3, and a b* value in the range of about -6 to about +6. Alternatively, the glass article can exhibit CIELAB color space coordinates under the CIE illuminant F02 with an L* value of about 40 or less, an a* value in the range of about -3 to about +3, and a b* value in the range of about -6 to about +6. Such color space coordinates may exist under other CIE illuminants (e.g., D65).

[0102] The selection of the substrate is not particularly limited. In some examples, glass articles can be described as having high cation diffusivity for ion exchange. In one or more embodiments, the glass or glass ceramic has high-speed ion exchange ability, that is, the glass or glass ceramic has a monovalent ion diffusivity of about 450 μm / hour or more at 460 °C or about 500 μm / hour or more at 460 °C. In one or more embodiments, the glass or glass ceramic has a sodium ion diffusivity of about 450 μm / hour or more at 460 °C or about 500 μm / hour or more at 460 °C. In one or more embodiments, the glass or glass ceramic has a potassium ion diffusivity of about 450 μm / hour or more at 460 °C or about 500 μm / hour or more at 460 °C. 2 / hour or more or about 500 μm / hour or more at 460 °C. 2 / hour or more at 460 °C. In one or more embodiments, the glass or glass ceramic has a monovalent ion diffusivity of about 450 μm / hour or more at 460 °C or about 500 μm / hour or more at 460 °C. 2 / hour or more or about 500 μm / hour or more at 460 °C. 2 / hour or more at 460 °C. In one or more embodiments, the glass or glass ceramic has a sodium ion diffusivity of about 450 μm / hour or more at 460 °C or about 500 μm / hour or more at 460 °C. 2 / hour or more or about 500 μm / hour or more at 460 °C. 2 / hour or more at 460 °C.

[0103] The glass article may include an amorphous substrate, a crystalline substrate, or a combination thereof (e.g., a glass ceramic substrate). In one or more embodiments, the glass article substrate (before being chemically strengthened as described herein) can have a glass composition in mole percent (mol%) as follows.

[0104] SiO2 in the range of about 40 to about 80, Al2O3 in the range of about 10 to about 30, B2O3 in the range of about 0 to about 10, R2O in the range of about 0 to about 20, and RO in the range of about 0 to about 15. As used herein, R2O refers to the total amount of alkali metal oxides such as Li2O, Na2O, K2O, Rb2O, and Cs2O. As used herein, RO means the total amount of alkaline earth metal oxides such as MgO, CaO, SrO, BaO, and ZnO. In some examples, the composition can include one or both of ZrO2 in the range of about 0 mol% to about 5 mol% and P2O5 in the range of about 0 mol% to about 15 mol%. TiO2 can be present in an amount of about 0 mol% to about 2 mol%.

[0105] In some embodiments, the glass composition may contain SiO2 in an amount in the range of about 45 to about 80, about 45 to about 75, about 45 to about 70, about 45 to about 65, about 45 to about 60, about 45 to about 65, about 45 to about 65, about 50 to about 70, about 55 to about 70, about 60 to about 70, about 70 to about 75, about 70 to about 72, or about 50 to about 65 mol%.

[0106] In some embodiments, the glass composition may contain Al2O3 in an amount in the range of about 5 to about 28, about 5 to about 26, about 5 to about 25, about 5 to about 24, about 5 to about 22, about 5 to about 20, about 6 to about 30, about 8 to about 30, about 10 to about 30, about 12 to about 30, about 12 to about 18, or about 12 to about 14 mol%.

[0107] In one or more embodiments, the glass composition may contain B2O3 in an amount in the range of about 0 to about 8, about 0 to about 6, about 0 to about 4, about 0.1 to about 8, about 0.1 to about 6, about 0.1 to about 4, about 1 to about 10, about 2 to about 10, about 4 to about 10, about 2 to about 8, about 0.1 to about 5, or about 1 to about 3 mol%. In some examples, the glass composition may be substantially free of B2O3. As used herein, the phrase "substantially free of" with respect to a component of a composition means that the component is not actively or intentionally added to the composition in the initial batch, but may be present as an impurity in an amount less than about 0.001 mol%.

[0108] In some embodiments, the glass composition can include one or more alkaline earth metal oxides such as MgO, CaO, and ZnO. In some embodiments, the total amount of the one or more alkaline earth metal oxides can be a non-zero amount up to about 15 mol%. In one or more specific embodiments, the total amount of any of the alkaline earth metal oxides can be a non-zero amount up to about 14 mol%, up to about 12 mol%, up to about 10 mol%, up to about 8 mol%, up to about 6 mol%, up to about 4 mol%, up to about 2 mol%, or up to about 1.5 mol%. In some embodiments, the total amount in mol% of the one or more alkaline earth metal oxides can be in the range of about 0.1 to 10, about 0.1 to 8, about 0.1 to 6, about 0.1 to 5, about 1 to 10, about 2 to 10, or about 2.5 to 8. The amount of MgO can be in the range of about 0 mol% to about 5 mol% (e.g., about 2 mol% to about 4 mol%). The amount of ZnO can be in the range of about 0 to about 2 mol% (e.g., about 0.1 mol% to about 2 mol%, about 0.1 mol% to about 1 mol%, or about 0.5 mol% to about 1.5 mol%). The amount of CaO can be about 0 mol% to about 2 mol%. In one or more embodiments, the glass composition may contain MgO, or may not substantially contain CaO and ZnO. In one variation, the glass composition may contain either CaO or ZnO, and may not substantially contain the other of MgO, CaO, and ZnO. In one or more specific embodiments, the glass composition may contain only two of the alkaline earth metal oxides of MgO, CaO, and ZnO, and may not substantially contain the third earth metal oxide.

[0109] The total amount in mol% of the alkali metal oxide R2O in the glass composition can be in the range of about 5 to about 20, about 5 to about 18, about 5 to about 16, about 5 to about 15, about 5 to about 14, about 5 to about 12, about 5 to about 10, about 5 to about 8, about 5 to about 20, about 6 to about 20, about 7 to about 20, about 8 to about 20, about 8 to about 18, about 8 to about 16, about 8 to about 14, about 8 to about 12, or about 8 to about 11.

[0110] In one or more embodiments, the glass composition comprises Na2O in an amount in the range of about 0 mol% to about 18 mol%, about 0 mol% to about 16 mol% or about 0 mol% to about 14 mol%, about 0 mol% to about 12 mol%, about 1 mol% to about 18 mol%, about 1 mol% to about 16 mol%, about 1 mol% to about 14 mol%, about 1 mol% to about 12 mol%, about 1 mol% to about 10 mol%, about 1 mol% to about 8 mol%, about 1 mol% to about 5 mol%, about 1 mol% to about 4 mol% or about 1 mol% to about 3 mol%. In some embodiments, the composition may contain less than about 4 mol% Na2O.

[0111] In some embodiments, the amounts of Li2O and Na2O are controlled to specific amounts or ratios in order to balance formability and ion exchangeability. For example, as the amount of Li2O increases, the liquid phase viscosity decreases and some forming methods may not be used. However, such glass compositions are ion-exchanged to a deeper DOC level as described herein. The amount of Na2O can change the liquid phase viscosity but can suppress ion exchange to a deeper DOC level. In one or more embodiments, in order to obtain sufficient stress at a given depth in a Li2O-containing glass composition (or a composition in which the exchange of Na+ for Li+ is the main strengthening mechanism), the glass composition of one or more embodiments comprises a composition ratio of Li2O / (R2O) that is greater than about 0.3, about 0.45 or greater, about 0.5 or greater or about 0.7 or greater. In order to maintain a higher CS value at a greater depth in the glass articles described herein, particularly glass articles containing Na2O (or a composition in which the exchange of K+ for Na+ is the main strengthening mechanism), the glass composition of one or more embodiments comprises a composition ratio of Na2O / (R2O) that is greater than about 0.3, about 0.5 or greater or about 0.7 or greater.

[0112] In one or more embodiments, the glass composition may contain K2O in an amount less than about 5 mol%, less than about 4 mol%, less than about 3 mol%, less than about 2 mol% or less than about 1 mol%. In one or more other embodiments, the glass composition may be substantially free of K2O as defined herein.

[0113] In one or more embodiments, the glass composition may contain Li2O in an amount of from about 0 mol% to about 18 mol%, from about 0 mol% to about 15 mol%, or from about 0 mol% to about 10 mol%, from about 0 mol% to about 8 mol%, from about 0 mol% to about 6 mol%, from about 0 mol% to about 4 mol%, or from about 0 mol% to about 2 mol%. In some embodiments, the glass composition may contain Li2O in an amount of from about 2 mol% to about 10 mol%, from about 4 mol% to about 10 mol%, from about 6 mol% to about 10 mol, or from about 5 mol% to about 8 mol%. In one or more other embodiments, the glass composition may be substantially free of Li2O as defined herein.

[0114] In one or more embodiments, the glass composition may contain Fe2O3. In such embodiments, Fe2O3 may be present in an amount of less than about 1 mol%, less than about 0.9 mol%, less than about 0.8 mol%, less than about 0.7 mol%, less than about 0.6 mol%, less than about 0.5 mol%, less than about 0.4 mol%, less than about 0.3 mol%, less than about 0.2 mol%, less than about 0.1 mol%, and all ranges and sub-ranges therebetween. In one or more other embodiments, the glass composition may be substantially free of Fe2O3 as defined herein.

[0115] In one or more embodiments, the glass composition may contain ZrO2. In such embodiments, ZrO2 may be present in an amount of less than about 1 mol%, less than about 0.9 mol%, less than about 0.8 mol%, less than about 0.7 mol%, less than about 0.6 mol%, less than about 0.5 mol%, less than about 0.4 mol%, less than about 0.3 mol%, less than about 0.2 mol%, less than about 0.1 mol%, and all ranges and sub-ranges therebetween. In one or more other embodiments, the glass composition may be substantially free of ZrO2 as defined herein.

[0116] In one or more embodiments, the glass composition may contain P2O5 in the range of about 0 mol% to about 10 mol%, about 0 mol% to about 8 mol%, about 0 mol% to about 6 mol%, about 0 mol% to about 4 mol%, about 0.1 mol% to about 10 mol%, about 0.1 mol% to about 8 mol%, about 2 mol% to about 8 mol%, about 2 mol% to about 6 mol%, or about 2 mol% to about 4 mol%. In some examples, the glass composition may be substantially free of P2O5.

[0117] In one or more embodiments, the glass composition may contain TiO2. In such embodiments, TiO2 may be present in an amount of less than about 6 mol%, less than about 4 mol%, less than about 2 mol%, or less than about 1 mol%. In one or more other embodiments, the glass composition may be substantially free of TiO2 as defined herein. In some embodiments, TiO2 is present in an amount in the range of about 0.1 mol% to about 6 mol%, or about 0.1 mol% to about 4 mol%.

[0118] In some embodiments, the glass composition can include various compositional relationships. For example, the glass composition can include a ratio of the amount (mol%) of Li2O to the total amount (mol%) of R2O in the range of about 0 to about 1, about 0.4 to about 1, about 0.45 to about 1, about 0.5 to about 1, or about 0.6 to about 1.

[0119] In some embodiments, the glass composition can include a difference between the total amount (mol%) of R2O and the amount (mol%) of Al2O3 (R2O - Al2O3) in the range of about -5 to about 2 (e.g., about -5 to about 1.5, about -5 to about 1, about -5 to about 0, about -5 to about -1, about -5 to about -2, about -4 to about 2, about -3 to about 2, about -2 to about 2, or about -3 to about -1).

[0120] In some embodiments, the glass composition can include a difference between the total amount (mol%) of RxO and the amount (mol%) of Al2O3 (RxO - Al2O3) within the range of about 0 to about 5 (e.g., about 0 to about 4, about 0 to about 3, about 0.1 to about 4, about 0.1 to about 3, about 1 to about 3, or about 1 to about 2). As used herein, RxO includes R2O and RO as defined herein.

[0121] In some embodiments, the glass composition can have a ratio (R2O / Al2O3) of the total amount (mol%) of R2O to the amount (mol%) of Al2O3 within the range of about -4 to about 5, about -2 to about 4, or about 0.1 to about 5. For example, the ratio (R2O / Al2O3) of the total amount (mol%) of R2O to the amount (mol%) of Al2O3 can be within the range of about -4 to about 4.5, about -4 to about 4, about -4 to about 3.5, about -4 to about 3, about -4 to about 2.5, about -4 to about 2, about -4 to about 1.5, about -4 to about 1, about -3.5 to about 5, about -3 to about 5, about -2.5 to about 5, about -2 to about 5, about -1.5 to about 5, about -1 to about 5, about 0 to about 5, about 0 to about 4, about 0 to about 3, about 0.1 to about 4, about 0.1 to about 3, or about 0.1 to about 2.

[0122] In one or more embodiments, the glass composition has a combined amount of Al2O3 and Na2O of about 15 mol% or less (e.g., 14 mol% or less, 13 mol% or less, 12 mol% or less, 11 mol% or less, or about 10.5 mol% or less). The combined amount of Al2O3 and Na2O can be greater than about 5 mol%.

[0123] The glass composition of one or more embodiments can exhibit a ratio of the amount (mol%) of MgO to the total amount (mol%) of RO within the range of about 0 to about 1. In some embodiments, the MgO / RO ratio is within the range of about 0 to about 0.9, about 0 to about 0.8, about 0 to about 0.7, about 0 to about 0.6, about 0 to about 0.5, about 0.1 to about 1, about 0.2 to about 1, about 0.3 to about 1, about 0.4 to about 1, or about 0.5 to about 1.

[0124] In some embodiments, the glass composition may substantially contain no nucleating agent. Examples of typical nucleating agents are TiO2, ZrO2, etc. A nucleating agent can be described in terms of its function as a constituent in the glass that can initiate the formation of microcrystals in the glass.

[0125] In some embodiments, the composition used for the glass substrate can be batch-formed using about 0 mol% to about 2 mol% of at least one fining agent selected from any one or more of Na2SO4, NaCl, NaF, NaBr, K2SO4, KCl, KF, KBr, As2O3, Sb2O3, and SnO2. The glass composition according to one or more embodiments can further contain SnO2 in the range of about 0 to about 2, about 0 to about 1, about 0.1 to about 2, about 0.1 to about 1, or about 1 to about 2. The glass composition disclosed herein may substantially contain no As2O3 and / or Sb2O3.

[0126] In one or more embodiments, the composition can specifically contain 62 mol% to 75 mol% of SiO2, 10.5 mol% to about 17 mol% of Al2O3, 5 mol% to about 13 mol% of Li2O, 0 mol% to about 4 mol% of ZnO, 0 mol% to about 8 mol% of MgO, 2 mol% to about 5 mol% of TiO2, 0 mol% to about 4 mol% of B2O3, 0 mol% to about 5 mol% of Na2O, 0 mol% to about 4 mol% of K2O, 0 mol% to about 2 mol% of ZrO2, 0 mol% to about 7 mol% of P2O5, 0 mol% to about 0.3 mol% of Fe2O3, 0 mol% to about 2 mol% of MnOx, and 0.05 mol% to about 0.2 mol% of SnO2.

[0127] In one or more embodiments, the composition can include 67 mol% to about 74 mol% SiO2, 11 mol% to about 15 mol% Al2O3, 5.5 mol% to about 9 mol% Li2O, 0.5 mol% to about 2 mol% ZnO, 2 mol% to about 4.5 mol% MgO, 3 mol% to about 4.5 mol% TiO2, 0 mol% to about 2.2 mol% B2O3, 0 mol% to about 1 mol% Na2O, 0 mol% to about 1 mol% K2O, 0 mol% to about 1 mol% ZrO2, 0 mol% to about 4 mol% P2O5, 0 mol% to about 0.1 mol% Fe2O3, 0 mol% to about 1.5 mol% MnOx, and 0.08 mol% to about 0.16 mol% SnO2.

[0128] In one or more embodiments, the composition can include 70 mol% to 75 mol% SiO2, 10 mol% to about 15 mol% Al2O3, 5 mol% to about 13 mol% Li2O, 0 mol% to about 4 mol% ZnO, 0.1 mol% to about 8 mol% MgO, 0 mol% to about 5 mol% TiO2, 0.1 mol% to about 4 mol% B2O3, 0.1 mol% to about 5 mol% Na2O, 0 mol% to about 4 mol% K2O, 0 mol% to about 2 mol% ZrO2, 0 mol% to about 7 mol% P2O5, 0 mol% to about 0.3 mol% Fe2O3, 0 mol% to about 2 mol% MnOx, and 0.05 mol% to about 0.2 mol% SnO2.

[0129] Other exemplary compositions of the glassy article before chemically strengthening as described herein are shown in Table 1A. Table 1B lists selected physical properties determined for the examples listed in Table 1A. The physical properties listed in Table 1B include density; low and high temperature CTE; strain, annealing, and softening points; 1011 poise, 35 kP, 200 kP, liquid phase, and zircon breakdown temperatures; zircon decomposition and liquid phase viscosities; Poisson's ratio; Young's modulus; refractive index, and stress optical coefficient. In some embodiments, the glassy article and glass substrate described herein have a high temperature CTE of 30 ppm / °C or less and / or a Young's modulus of 70 GPa or more, and in some embodiments, the Young's modulus is up to 80 GPa.

[0130]

Table 1A

[0131]

Table 1B

[0132] Table 1C shows the properties of Example H after ion exchange at a temperature of 430 °C for 16 hours in a molten salt bath having 80% KNO3 and 20% NaNO3.

[0133]

Table 1C

[0134] Here, the glass-based article includes glass-ceramics, and the crystalline phase may include β-spodumene, rutile, garnet or other known crystalline phases and combinations thereof.

[0135] The glass-based article may be substantially planar, but other embodiments may utilize curved or other shaped or etched substrates. In some examples, the glass-based article can have a 3D or 2.5D shape. The glass-based article may be substantially optically transparent, transparent and free of light scattering. The glass-based article may have a refractive index in the range of about 1.45 to about 1.55. As used herein, the refractive index value is the value for a wavelength of 550 nm.

[0136] In addition, or alternatively, the thickness of the glass-based article may be constant along one or more dimensions of two or more dimensions, or may vary along one or more of those dimensions for aesthetic and / or functional reasons. For example, the ends of the glass-based article may be thicker than the more central regions of the glass-based article. The dimensions of the length, width and thickness of the glass-based article may also vary depending on the use or application of the article.

[0137] Glass articles can be characterized by the method by which they are formed. For example, glass articles can be characterized by being floatable (i.e., formed by the float process), drawable downwards, particularly fusible or slot-drawable (i.e., formed by a down-draw process such as the fusion draw process or the slot draw process).

[0138] Floatable glass articles are characterized by a smooth surface, and the uniform thickness is created by molten glass floating on a layer of molten metal, typically tin. In one exemplary process, the molten glass supplied onto the surface of the molten tin layer forms a floating glass ribbon. As the glass ribbon flows along the tin bath, the temperature gradually decreases until the glass ribbon solidifies into a solid glass article, and the glass ribbon can be pulled up from the tin onto rollers. Once out of the bath, the glass article can be further cooled and annealed to reduce internal stresses. Here, the glass article is a glass-ceramic, and the glass article formed by the float process can be subjected to a ceramization treatment, whereby one or more crystalline phases are produced.

[0139] The down-draw process produces a glass article of uniform thickness with a relatively pristine surface. Since the average bending strength of the glass article is controlled by the amount and size of surface flaws, the relatively pristine surface with less contact has a higher initial strength. When this high-strength glass article is subsequently further strengthened (e.g., chemically), the resulting strength can be higher than that of a glass article with a covered and polished surface. The down-draw glass article can be drawn to a thickness of less than about 2 mm. Further, the down-draw glass article has a very flat and smooth surface that can be used for end-use without expensive grinding and polishing. Here, the glass article is a glass-ceramic, and the glass article formed from the down-draw process can be subjected to a ceramization treatment, whereby one or more crystalline phases are produced.

[0140] The fusion draw process uses, for example, a draw tank having a channel for receiving a molten glass feed. The channel has weirs open upward along the length of the channel on both sides of the channel. When the channel is filled with the molten material, the molten glass overflows the weirs. Due to gravity, the molten glass flows down the outer surfaces of the draw tank as two flowing glass films. These outer surfaces of the draw tank extend downward and inward so as to join at the lower end of the draw tank. The two flowing glass films join and fuse at this end to form a single flowing glass-based article. The fusion draw method provides the advantage that neither of the outer surfaces of the resulting glass-based article contacts any part of the apparatus since the two glass films flowing over the channel fuse. That is, the surface properties of the fusion drawn glass-based article are not affected by such contact. Here, the glass-based article is a glass ceramic, and the glass-based article formed from the fusion process can be subjected to a ceramization treatment, whereby one or more crystal phases are produced.

[0141] The slot draw process is different from the fusion draw method. In the slot draw process, molten raw material glass is supplied to a draw tank. At the bottom of the draw tank, there is an open slot having a nozzle extending along the length of the slot. The molten glass flows through the slot / nozzle and is drawn downward as a continuous glass-based article and enters an annealing zone. Here, the glass-based article is a glass ceramic, and the glass-based article formed from the slot draw process can be subjected to a ceramization treatment, whereby one or more crystal phases are produced.

[0142] In some embodiments, the glass article can be formed using the thin rolling process described in the specifications of U.S. Patent No. 8,713,972 entitled "Precision Glass Roll Forming Process and Apparatus", U.S. Patent No. 9,003,835 entitled "Precision Roll Forming of Textured Sheet Glass", U.S. Patent Publication No. 20150027169 entitled "Method and Apparatus for Forming a Glass Ribbon", and U.S. Patent Publication No. 20050099618 entitled "Apparatus and Method for Forming a Thin Glass Article", the entire contents of which are incorporated herein by reference. More specifically, the glass article provides a vertical flow of molten glass and forms a supplied flow of molten glass or glass-ceramic using a pair of forming rolls maintained at a surface temperature of about 500 °C or higher or about 600 °C or higher to form a formed glass ribbon having a formed thickness, and sizes the formed glass ribbon using a pair of sizing rolls maintained at a surface temperature of about 400 °C or lower to produce a sized glass ribbon having a desired thickness smaller than the formed thickness and a desired thickness uniformity. The apparatus used to form the glass ribbon includes a glass supply device for supplying the supplied molten glass flow; a pair of forming rolls maintained at a surface temperature of about 500 °C or higher, which are arranged adjacent to and spaced apart from each other, defining a glass forming gap between the forming rolls, the glass forming gap being vertically disposed below the glass supply device to receive the supplied molten glass flow and narrowing the supplied molten glass flow between the forming rolls to form a formed glass ribbon having a formed thickness; and a pair of sizing rolls maintained at a surface temperature of about 400 °C or lower, the sizing rolls being arranged adjacent to and spaced apart from each other, defining a glass sizing gap between the sizing rolls, the glass sizing gap being vertically disposed below the forming rolls to receive the formed glass ribbon and narrowing the formed glass ribbon to produce a sized glass ribbon having a desired thickness and a desired thickness uniformity.

[0143] In some examples, when the viscosity of the glass does not permit the use of the fusion or slot-draw method, a thin rolling process can be utilized. For example, when the glass exhibits a liquid-phase viscosity of less than 100 kP, a thin rolling process can be used to form a glass-based article.

[0144] The glass-based article may be acid-etched or otherwise treated to remove or reduce the effect of surface scratches. Another aspect of the present disclosure relates to a device including the glass-based article described herein. For example, the device can include a display or any device that requires strengthened thin glass. In one or more embodiments, the device can be a portable device such as a mobile phone, laptop computer, tablet, mp3 player, navigation device, etc., or an electronic device that can include a fixed device such as a computer, electronic display, in-vehicle information / entertainment system, bulletin board, point-of-sale management system, navigation system, etc. In some embodiments, the glass-based article described herein can be incorporated into a building article (walls, fixtures, panels, windows, etc.), a conveyance article (e.g., glazing or interior in automotive applications, trains, airplanes, marine vessels, etc.), an electrical appliance (e.g., washing machine, dryer, dishwasher, refrigerator, etc.) or any article that requires a certain degree of fracture resistance. As shown in FIG. 39, the electronic device 1000 can include a glass-based article 100 according to one or more embodiments described herein. The device 100 includes a housing 1020 having a front surface 1040, a back surface 1060, and side surfaces 1080; and an electrical component (not shown) at least partially within or entirely within the housing and including at least a controller, a memory, and a display 1120 positioned on or adjacent to the front surface of the housing. The glass-based article 100 is shown as a cover disposed on or over the front surface of the housing so as to be over the display 1120. In some embodiments, the glass-based article can be used as a back cover.

[0145] Another aspect of the present disclosure relates to a method of forming a damage resistant glass-based article. The method includes providing a glass-based substrate having a first surface and a second surface defining a thickness of about 3 millimeters or less, such as about 1 millimeter or less, and generating a stress profile in the glass-based substrate as described herein to provide a damage resistant glass-based article. In one or more embodiments, generating the stress profile includes ion-exchanging a plurality of alkali ions within the glass-based substrate to form a non-zero alkali metal oxide concentration that varies along a substantial portion (as described herein) or the entire thickness. In one example, generating the stress profile includes immersing the glass-based substrate in a molten salt bath having a temperature of about 350° C. or greater (e.g., about 350° C. to about 500° C.) and including a nitrate of Na+, K+, Rb+, Cs+, or combinations thereof. In one example, the molten bath can include NaNO3, KNO3, or combinations thereof and can have a temperature of about 485° C. or less. In another example, the bath can include a mixture of NaNO3 and KNO3 and can have a temperature of about 460° C. The glass-based substrate can be immersed in the bath for about 2 hours or more and up to about 48 hours (e.g., about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 2 hours to about 6 hours, about 3 hours to about 10 hours, or about 3.5 hours to about 10 hours).

[0146] In some embodiments, the method can include chemically strengthening or ion-exchanging the glass-based substrate in a single bath or in multiple steps using sequential immersion steps in multiple baths. For example, two or more baths can be used sequentially. The composition of one or more baths can include a single metal (e.g., Ag+, Na+, K+, Rb+, or Cs+) or a combination of metals within the same bath. When two or more baths are utilized, the baths can have the same or different compositions and / or temperatures relative to each other. The immersion time in each such bath can be the same or can be varied to provide a desired stress profile.

[0147] In one or more embodiments of this method, a second bath or subsequent baths can be utilized to generate a larger surface CS. In some examples, the method includes immersing a glass-based substrate in a second or subsequent bath to generate a larger surface CS without significantly affecting the chemical depth and / or DOC of the layer. In such embodiments, the second or subsequent bath can include a single metal (e.g., KNO3 or NaNO3) or a mixture of metals (KNO3 and NaNO3). The temperature of the second or subsequent bath can be adjusted to generate a larger surface CS. In some embodiments, the immersion time of the glass-based substrate in the second or subsequent bath can also be adjusted to generate a larger surface CS without affecting the chemical depth and / or DOC of the layer. For example, the immersion time in the second or subsequent bath can be less than 10 hours (e.g., about 8 hours or less, about 5 hours or less, about 4 hours or less, about 2 hours or less, about 1 hour or less, about 30 minutes or less, about 15 minutes or less, or about 10 minutes or less).

[0148] In one or more other embodiments, the method can include one or more heat treatment steps that can be used in combination with the ion exchange method described herein. This heat treatment includes heat treating the glass-based article to obtain a desired stress profile. In some embodiments, the heat treatment includes annealing, tempering, or heating the glass-based substrate to a temperature within the range of about 300°C to about 600°C. The heat treatment can continue for 1 minute to about 18 minutes. In some embodiments, the heat treatment can be used after or during one or more ion exchange processes.

Example

[0149] The various embodiments will be further clarified by the following examples. In the examples, before strengthening, the examples are referred to as "substrates". After strengthening, the examples are referred to as "articles" or "glass-based articles".

[0150] Example 1 A glass-ceramic substrate having the nominal composition shown in Table 2 below was provided. The glass-ceramic substrate had a thickness of 0.8 millimeters and included a crystal phase population including a β-spodumene solid solution as the main crystal phase and one or more secondary phases including rutile. The glass-ceramic substrate was immersed in a molten salt bath containing NaNO3 at a temperature of 485 °C for 10 hours (Condition A), 13 hours (Condition B), or 24 hours (Condition C), or in a molten salt bath containing NaNO3 at a temperature of 430 °C for 2 hours (Comparative Condition D) to form a glass-ceramic article.

[0151] [Table 2]

[0152] The chemical profile of the glass-ceramic article was measured by a microprobe and is shown in FIG. 9. The stress is proportional to the concentration according to Equation (4).

[0153] Sigma(z) = BE / 1 - n(Cavg - C(z)) (4) In Equation (4), B is the lattice expansion coefficient, E is the Young's modulus, n is the Poisson's ratio, and Cavg is the integral of the concentration across the sample. As shown in FIG. 9, Na+ ions are ion-exchanged through substantially the entire thickness of the article when a higher temperature bath is used (i.e., Conditions A - C). In such glass-ceramics, Na2O is present in the CT region in an amount of about 1.2 mol% or more. The glass-ceramic article ion-exchanged in the low temperature bath (Comparative Condition D) showed a stress profile similar to the known stress profile.

[0154] Example 2 A glass substrate having a thickness of 0.8 mm, the same composition as shown in Table 2 but having an amorphous structure (no crystalline phase) was chemically strengthened by immersing it in a molten salt bath containing 100% NaNO3 at a temperature of about 430°C for various durations to provide a glass article. The DOC and maximum CT values of the glass article were measured using SCALP. As shown in Figure 10, the increase in DOC and maximum CT depends on the length of immersion or ion exchange. The maximum CT value was observed after immersing the glass for about 16 hours.

[0155] The stress profile of the glass article of Example 2 was measured using SCALP and is shown in Figure 11. The upper part of the y-axis showing positive stress values is the CT layer, and the lower part of the y-axis showing negative stress values is the CS value. The stress profile of the glass article chemically strengthened for 16 hours showed a parabolic shape with a maximum CT value (i.e., 175 MPa) and no substantially flat portion in the depth direction of 100 μm. The surface CS measured by SCALP was about 410 MPa. Therefore, the ratio of the maximum CT to the absolute value of the surface CS of Example 2 was about 0.4375. In Figure 11, positive numbers are used for compressive stress, and negative numbers indicate tensile stress. This same rule (compressive stress is shown as a positive value on the y-axis, and tensile stress is indicated by a negative value on the y-axis) is also used in Figures 1 to 3 and 33. However, in the remaining figures, compressive stress is shown as a negative value on the y-axis, and tensile stress is shown as a positive value on the y-axis.

[0156] Example 3 For comparison, the glass ceramic substrate of Example 1 and the glass substrate of Example 2, each having a thickness of about 0.8 mm, were chemically strengthened by immersing them in a molten salt bath of NaNO3 at a temperature of 350°C for 3.5 hours (Examples 3A and 3B, respectively). The resulting stress profiles of the glass-ceramic article and the glass article shown in Figure 12 (approximated by the chemical profiles measured by a microprobe using Equation 4) are similar to an error function (erfc) or quasi-linear. Furthermore, the CS depth of the layer is smaller than the depth of the alkali ion-exchanged into the glass or glass ceramic (or the chemical ion-exchange depth).

[0157] When the glass-ceramic substrate of Example 1 and the glass substrate of Example 2, each having a thickness of about 0.8 mm, are subjected to the chemical strengthening described herein by immersing them in a molten salt bath of NaNO3 at a temperature of 430 °C for 24 hours (Examples 3C and 3D, respectively), the resulting glass articles showed a metal oxide concentration profile (obtained by EPMA) as shown in FIG. 13. The metal oxide concentration profile is parabolic and shows ion exchange of Na+ ions throughout the thickness. The chemical profile was measured using EMPA, and the chemical depth of Na2O diffusion is shown to be 400 micrometers or more. Further, Na2O is present throughout the thickness including in the CT layer at a concentration of about 1 mol% or more. The obtained glass-ceramic article of Example 3D showed excellent fracture resistance in a drop test in which the glass-ceramic substrate was incorporated into the same mobile phone housing. Specifically, five samples of Example 3D were incorporated into a mobile phone device and continuously dropped onto sandpaper starting from a height of 50 cm. When each sample survived a drop from a certain height, it was dropped again from an increased height until it broke, and the defect height of that sample at that point was recorded in FIG. 13A. Example 3D showed an average defect height of 172.5 cm.

[0158] FIG. 14 shows the stress profiles of a glass substrate chemically strengthened according to a known method and a glass substrate chemically strengthened according to the method described herein. As shown in FIG. 14, the stress profile of the glass article of the embodiments described herein has substantially no flat portion (having a length or absolute depth exceeding about 50 micrometers) and has a shape showing a DOC of about 0.2·t, while the known stress profile shows a substantially linear and / or flat portion at a depth of about 0.1 millimeter to about 0.7 millimeter (a total length of about 0.6 millimeter or 600 micrometers). The known stress profile also shows a lower CT value and a lower DOC.

[0159] Example 4 A glass substrate having the composition of Table 2 (each about 1 mm thick) was chemically strengthened by immersion in a first molten salt bath of NaNO3 at a temperature of 430 °C for 24 hours. One glass article did not undergo a further strengthening step (Example 4A). Three glass articles were subjected to a second strengthening step by immersion in a second molten salt bath of KNO3 at a temperature of about 430 °C for either 0.75 hours, 4 hours or 8 hours (Examples 4B, 4C and 4D respectively). The stress profiles measured by SCALP of the resulting glass articles are shown in FIG. 15, with the depth or thickness of the glass article plotted on the x-axis and the stress plotted on the y-axis. Positive stress values are CT values and negative stress values are CS values. The spatial resolution of the apparatus prohibits measurement of CS associated with the second KNO3 ion exchange step. The glass articles of Examples 4A and 4B showed similar profiles. The glass articles of Examples 4C and 4D showed a decreasing CT and a decreasing CS (compared to Examples 4A and 4B) with the passage of time during and after immersion in the second strengthening step. The glass articles of Examples 4C and 4D also showed an increased DOC compared to Examples 4A and 4B, and such DOC values were greater than 0.2·t.

[0160] FIG. 16 shows the stored tensile energy for each of Examples 4B - 4D in J / m 2 and is greater than 15 J / m depending on the time of immersion in the second molten salt bath of KNO3. The stored tensile energy can be calculated from the measured SCALP stress profile data using equation (2) above. 2

[0161] Figures 17 and 18 show the concentration profiles of K2O and Na2O, respectively, as a function of the respective depth (in micrometers) for Examples 4B to 4D. As shown in Figure 17, the chemical depths of K2O are 3 micrometers (Example 4B, immersed in a KNO3 bath for 0.75 hours), 6 micrometers (Example 4C, immersed in a KNO3 bath for 4 hours), and 5 micrometers (Example 4D, immersed in a KNO3 bath for 8 hours). As shown in Figure 18, Na2O penetrates throughout the depth and has a concentration of about 1 mol% or more for each of Examples 4B to 4D along the entire depth of the glass article.

[0162] Examples 4E and 4F included glass substrates having the compositions in Table 2 (each about 1 mm thick), which were chemically strengthened by immersing them in a first molten salt bath of NaNO3 at a temperature of 430 °C for 24 hours, and then heat-treated at a temperature of 430 °C in air for 4 hours or 8.25 hours, respectively. The stress profiles of the glass articles of Examples 4E and 4F are shown in Figure 19, and for comparison, the stress profiles of Examples 4A, 4C, and 4D are shown. Figure 20 shows the same graph as Figure 19 but on a smaller scale to show the differences in the stress profiles at a depth of 0.5·t or near that depth.

[0163] Example 5 Glass substrates having the compositions in Table 2 (each about 1 mm thick) were chemically strengthened by immersing them in a first molten salt bath of NaNO3 at a temperature of 430 °C for 24 hours. One glass article was not subjected to a further strengthening step (Example 5A). Two glass articles were subjected to a second strengthening step by placing the glass articles in a furnace at 390 °C and maintaining the glass articles in the furnace for about 8 hours or 28 hours (Examples 5B and 5C, respectively). Four glass articles were subjected to a third strengthening step (after either the first strengthening step and a different second strengthening step) by immersing them in a second molten salt bath of KNO3 at a temperature of 430 °C for 4 hours or 8 hours (Examples 5D to 5G). The respective strengthening steps for Examples 5A to 5G are shown in Table 3. The measured CT values are also shown in Table 3.

[0164]

Table 3

[0165] The stress profiles of the obtained glass articles are shown in Fig. 21, where the depth or thickness of the glass article is plotted on the x-axis and the stress is plotted on the y-axis. Positive stress values are CT values and negative stress values are CS values. As shown in Fig. 21, as the duration of the second and / or third heat treatment increased, the DOC increased and the CT decreased. The decreases in DOC and CT are shown more clearly in Figs. 22 and 23, respectively.

[0166] Next, the glass articles of Examples 5A to 5G were subjected to a pork test in which one side of the glass article was taped and a sharp tool was struck against the bare surface on the opposite side to break it. The number of fragments obtained can be correlated with the storage tensile energy of the glass article. Examples 5A, 5B and 5D showed a large number of fragments (i.e., more than 50 and even 100 fragments), while Example 5F showed 10 fragments, Example 5C showed 3 fragments, and Examples 5E and 5G showed 4 fragments. Examples 5A, 5B and 5D, which were broken into numerous fragments, all showed a higher CT (greater than about 100 MPa) than Examples 5C, 5E, 5F and 5G, which all had CT values of about 100 MPa or less.

[0167] Example 6 Glass substrates having the nominal compositions shown in Table 2 and each having a thickness of about 1 mm were subjected to chemical strengthening in a molten salt bath containing 100% NaNO3 at a temperature of 430 °C. The time for immersing the glass substrates in the molten salt bath is shown in Table 5.

[0168]

Table 4

[0169] The stress profiles of the glass articles of Examples 6A to 6G are shown in FIG. 24. The stress profiles were measured using SCALP. As shown in FIG. 24, when the glass substrates are immersed in the molten salt bath for 16 hours and 24 hours, glass articles showing the maximum surface CS value and the maximum CT value in absolute value are obtained. FIG. 25 shows graphs showing the changes in the CT value and the storage tensile energy as a function of the ion exchange time in both cases.

[0170] Example 7 Glass substrates having the nominal compositions shown in Table 2 and each having a thickness of about 0.8 mm were chemically strengthened in a molten salt bath containing a mixture of NaNO3 and Na2SO4 at a temperature of 500 ° C. for 15 minutes (Comparative Example 7A) and 16 hours (Example 7B). The stress profiles of the glass articles of Comparative Example 7A and Example 7B are shown in FIG. 26. As shown in FIG. 26, Comparative Example 7A showed a known stress profile, while Example 7B showed a stress profile according to one or more embodiments of the present disclosure. The storage tensile energies of the glass articles of Comparative Example 7A and Example 7B were calculated in the same manner as in Examples 4B to 4D. The calculated storage tensile energy is plotted as a function of the measured CT (MPa) as shown in FIG. 27.

[0171] As shown in FIG. 27, for a given CT value, Comparative Example 7A showed a much larger storage tensile energy value than Example 7B (for the same CT value). In this figure, CT is the maximum CT in the sample. Specifically, at a CT of about 55 MPa, Comparative Example 7A showed a storage tensile energy of about 12.5 J / m 2 while Example 7B showed about 9 J / m 2The stored tensile energy was shown. When Comparative Example 7A and Example 7B were broken, Example 7B was broken into a smaller number than Comparative Example 7A, which was broken into a considerably larger number. Thus, without being bound by theory, it is considered that controlling the stored tensile energy may provide a way to control or predict the fragmentation pattern or the number of fragments resulting from breakage. In these examples, the CT was varied by maintaining the samples in the ion exchange bath for a long time using the same bath temperature and composition. In FIG. 27, point 0 was not experimentally tested, but a person skilled in the art can predict in that case, that is, when the CT is 0, the stored tensile energy is 0.

[0172] Glass substrates having the nominal compositions shown in Table 2 and each having a thickness of about 1 mm were chemically strengthened in a molten salt bath containing NaNO3 at a temperature of 430 °C for 4 hours (Comparative Example 7C) and 61.5 hours (Example 7D). Comparative Example 7C showed a known stress profile, while Example 7D showed a stress profile according to one or more embodiments of the present disclosure. The stored tensile energies of Examples 7C and 7D were calculated using the same method as that used in Examples 4B to 4D and were plotted as a function of the measured CT (MPa) as shown in FIG. 28.

[0173] As shown in FIG. 28, for a given CT value, Comparative Example 7C showed a considerably larger stored tensile energy value than Example 7D (for the same CT value) (here too, as in FIG. 27, these are the maximum CT values and, similarly, the same ion exchange bath temperature and composition were used, but the values were changed using a longer time). When Comparative Example 7C and Example 7D were broken, Example 7D was broken into a smaller number than Comparative Example 7C, which was broken into a considerably larger number.

[0174] Example 8 A glass substrate having a nominal composition of 70.9 mol% SiO2, 12.8 mol% Al2O3, 1.95 mol% B2O3, 7.95 mol% Li2O, 2.43 mol% Na2O, 2.98 mol% MgO, 0.89 mol% ZnO and 0.1 mol% SnO2 and having a thickness of about 0.8 mm was subjected to the ion exchange conditions in Table 5. Various properties of Example 8 were compared with those of Example 2 in Table 6.

[0175]

Table 5

[0176]

Table 6

[0177] When the stress profile of the glass-based article of Example 8 was measured, it showed the shape described herein.

[0178] Glass substrates according to Example 2, Comparative Examples 8A and 8B were provided with the same thickness as Example 8. The glass substrate according to Example 2 was ion-exchanged in a molten bath of 100% NaNO3 at a temperature of 430 °C for 33 hours. When Comparative Example 8A was ion-exchanged in a molten bath of 100% NaNO3 at a temperature of 390 °C for 16 hours, it also showed a known error function stress profile. The glass substrate according to Example 8B contains a nominal composition of 57.5 mol% SiO2, 16.5 mol% Al2O3, 16.7 mol% Na2O, 2.5 mol% MgO and 6.5 mol% P2O5, and when ion-exchanged, it showed a known error function stress profile. The term "error function stress profile" as used herein refers to a stress profile similar to that in FIG. 1.

[0179] Next, glass articles from Example 2, Example 8, and Comparative Examples 8A and 8B were incorporated into the same mobile phone device. The phone device was dropped onto 30 grit sandpaper from heights starting at 20 centimeters and increasing incrementally. If the glass article survived a drop from a certain height (e.g., 20 cm), the mobile phone was dropped again from a greater height (e.g., 30 cm, 40 cm, 50 cm, etc.). The height at which the glass article developed a defect is plotted in Figure 29, which also shows the average defect height for the samples of Example 2 and 8 and Comparative Examples 8A and 8B. As shown in Figure 29, Examples 2 and 8 showed defects at significantly greater drop heights than Comparative Examples 8A and 8B. Specifically, Comparative Examples 8A and 8B showed defects at drop heights of approximately 38 cm and 55 cm, respectively, while Examples 2 and 8 showed defects at drop heights of approximately 147 cm and 132 cm, respectively.

[0180] The same mobile phone device was used to repeat the same test on a new sample on 180 grit sandpaper. The average defect height for Comparative Example 8A was 204 cm, for Comparative Example 8B was 190 cm, for Example 2 was 214 cm, and for Example 8 was 214 cm.

[0181] When a glass substrate according to Comparative Example 8C having a nominal composition of 65 mol% SiO2, 5 mol% B2O3, 14 mol% Al2O3, 14 mol% Na2O, 2 mol% MgO, and 0.1 mol% SnO2 and having a thickness of 0.8 mm was ion-exchanged, a known error function stress profile was shown. Glass article samples of Example 2 and Comparative Example 8B (which show the above stress profile in this example), the glass article of Comparative Example 8C, and the glass article of Example 8 ion-exchanged according to Condition 4 as shown in Table 5 were subjected to the A-ROR test described herein.

[0182] Examples 6 and 8 and Comparative Example 8C were abraded using loads or pressures of 25 psi and 45 psi, and Example 2 was abraded using only a load of 25 psi. The AROR data is shown in FIG. 30. As shown in FIG. 30, Examples 2 and 8 showed higher defect loads than Comparative Example 8B and Comparative Example 8C at their respective abrasion loads or pressures.

[0183] A four-point bending test was performed on a glass article sample of Example 2 (ion-exchanged as described above in this example) and a glass article sample of Example 8 (ion-exchanged under Condition 4). The results are shown in the Weibull distribution diagram of FIG. 31. As shown in FIG. 31, Example 8 showed a higher stress or defect load (e.g., exceeding about 400 MPa).

[0184] As described above, glass articles made from compositions with a strain point exceeding 525 °C allow for an ion exchange temperature (or ion exchange bath temperature) within the range of about 350 °C to about 480 °C. In some embodiments, glass compositions exhibiting a monovalent ion diffusion rate exceeding about 800 square micrometers per hour allow the metal oxide diffusing into the glass article to quickly penetrate the entire depth or thickness of the article so that stress relaxation is minimized. Relaxation of excess stress can reduce the surface compressive stress of the glass article.

[0185] It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention.

[0186] Example 9 A glass substrate having the same composition as Example 8 and a thickness of about 0.8 mm was ion-exchanged by immersing it in a 100% NaNO3 molten salt bath at a temperature of 430 °C according to the conditions shown in Table 7. The resulting glass article showed a maximum CT value, which is plotted in FIG. 32 as a function of the ion exchange time.

[0187]

Table 7

[0188] The stress profile of Example 9D was measured using refractive near-field (RNF) measurements as described in U.S. Patent No. 8,854,623, entitled "Systems and Methods for Measuring Profile Characteristics of Glass Samples," which is hereby incorporated by reference in its entirety. FIG. 33 shows the measured stress as a function of depth extending from the surface of the glass article of Example 9D into the glass article. The stress at specific depths, including the "knee," which is the depth at which the slope of the stress changes abruptly, is shown in Table 8.

[0189]

Table 8

[0190] Example 10 Example 10A included a 0.8 mm thick glass substrate having the same composition as Example 1. The glass substrate was ion-exchanged for 16 hours in a single molten salt bath containing 80% KNO3 and 20% NaNO3 and having a temperature of about 430 °C. The resulting glass article exhibited a stress profile as described in Table 9.

[0191]

Table 9

[0192] The glass article according to Example 10A was subjected to the AROR test described herein. One set of glass articles was abraded using a load or pressure of 5 psi, a second set of glass articles was abraded at a load or pressure of 25 psi, and a third glass article was abraded using a load or pressure of 45 psi. The AROR data is shown in FIG. 34. As shown in FIG. 34, all of the glass articles according to Example 10A exhibited an average defect load exceeding about 25 kgf.

[0193] The glass article according to Example 10A was incorporated into the same mobile phone device. The phone device was dropped onto 180-grit sandpaper from heights starting at 20 centimeters and increasing incrementally. If the glass article remained intact when dropped from a height of 1 point (e.g., 20 cm), the mobile phone was dropped again from higher heights up to 225 cm (e.g., 30 cm, 40 cm, 50 cm, etc.). Next, the remaining glass article was dropped onto 30-grit sandpaper (inside the same phone device). The heights at which the glass article developed defects on both 180-grit sandpaper and 30-grit sandpaper were plotted in FIG. 35. As shown in FIG. 35, all but three of the glass articles of Example 10A remained intact after being dropped onto 180-grit sandpaper up to a height of about 225 cm (with an average remaining drop height of about 215 cm). The average remaining drop height on 30-grit sandpaper was 132 cm.

[0194] The glass article according to Example 10A exhibited a dielectric constant in the range of about 5.8 to about 6 over a frequency range of about 480 mHz to about 3000 mHz. The glass article according to Example 10A exhibited a dielectric tangent in the range of about 0.010 to about 0.013 over a frequency range of about 480 mHz to about 3000 mHz.

[0195] The refractive index of the glass article according to Example 10A was in the range of about 1.496 to about 1.523 over a wavelength range of about 380 nm to about 1550 nm, and in the range of about 1.496 to about 1.503 over a wavelength range of about 380 nm to about 800 nm.

[0196] The glass articles according to Example 10A were subjected to various chemical treatments as shown in Table 10. The chemical durability of the glass articles was compared with Comparative Examples 10B, 10C, and 10D. Comparative Example 10B was a glass substrate having a nominal composition of 64.3 mol% SiO2, 7.02 mol% B2O3, 14 mol% Al2O3, 14 mol% Na2O, 0.5 mol% K2O, 0.03 mol% Fe2O3, and 0.1 mol% SnO2. Comparative Example 10C was a glass substrate having a nominal composition of 64.75 mol% SiO2, 5 mol% B2O3, 14 mol% Al2O3, 13.75 mol% Na2O, 2.4 mol% MgO, and 0.08 mol% SnO2. Comparative Example 10D was a glass substrate having a nominal composition of 57.5 mol% SiO2, 16.5 mol% Al2O3, 16.71 mol% Na2O, 2.8 mol% MgO, 0.05 mol% SnO2, and 6.5 mol% P2O5.

[0197]

Table 10

[0198] Example 11 Example 11A included a 0.8-mm-thick glass substrate having the same composition as Example 1. Comparative Example 11B included a 0.8-mm-thick glass substrate having the same composition as Comparative Example 10D. The glass substrate of Example 11A was chemically strengthened in a single step using a single bath as described in Table 11. The glass substrate of Comparative Example 3B was ion-exchanged in a two-step process as described in Table 11.

[0199]

Table 11

[0200] The glass articles according to Example 11A and Comparative Example 11B were incorporated into the same mobile phone device. The phone device was dropped onto 30 grit sandpaper from heights starting at 20 centimeters and increasing incrementally. The height at which the glass articles showed defects on the 30 grit sandpaper was plotted in FIG. 36. As shown in FIG. 36, the glass article of Example 11A showed an average remaining drop height (i.e., 127 cm) that exceeded three times the average remaining drop height of Comparative Example 11B (i.e., 38 cm).

[0201] The glass articles according to Example 11A and Comparative Example 11B were subjected to the AROR test as described herein using a load or pressure of 25 psi. As shown in FIG. 37, the glass substrate of Example 10A showed an average defect load of about 31.3 kgf, while the glass substrate of Comparative Example 10B showed an average defect load of about 27.4 kgf. When the wear load or pressure was increased to 45 psi, the difference in the average defect loads between Example 10A and Comparative Example 10B increased. Specifically, as shown in FIG. 38, under a load or pressure of 45 psi, Example 10A showed an average defect load of about 28.9 kgf, while Comparative Example 10B showed an average defect load of about 19.6 kgf.

[0202] Example 12 Examples 12A and 12B included glass substrates having the nominal composition and a thickness of 0.8 mm as in Example 1H. When the glass substrate of Example 12A was chemically strengthened at 430 °C for 4.5 hours in a bath having 6.5% Na: 93.5% K, a CS of about 656, a DOL of about 8.1, and a C Sk (or compressive stress at the knee) of about 105 to about 130 MPa were obtained. When the substrate of Example 12B was chemically strengthened at 430 °C for 4.5 hours in a bath having 7% Na: 93% K, a CS of about 640 MPa, a DOL of about 8.2, and a C Sk of about 100 MPa were obtained. Examples 12A and 12B were subjected to the Inverted Ball Drop on Sandpaper (IBoS) test according to the procedure described herein. The test was performed using 30 grit sandpaper and a 4.2 g stainless steel ball with a diameter of 10 mm.

[0203]

Table 12

[0204] Sample set 12A showed an average fracture height of 88 cm. Further, 4 out of 5 samples withstood drop heights of 75 cm, 80 cm, 85 cm, 90 cm, and 95 cm respectively, resulting in a survival rate of 80% at each of these heights. Sample set 12B showed an average fracture height of 76 cm. Further, 3 out of 5 samples withstood drop heights of 75 cm, 80 cm, and 85 cm, resulting in a survival rate of 60% at each of these heights.

[0205] Sample sets 12A and 12B were also subjected to the Vickers scratch threshold test described above. Sample set 12A had a Vickers scratch threshold greater than 7 N and less than 14 N. On the other hand, sample set 12B had a Vickers scratch threshold greater than 10 N and less than 16 N.

[0206] It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention. For example, the various features can be combined according to the following exemplary embodiments.

[0207] Embodiment 1 A glass article comprising a first surface defining a thickness (t) and a second surface defining an area (square inches) opposite the first surface, having a concentration of metal oxide that is non-zero and varies along a thickness range of about 0·t to about 0.3·t, having a central tension (CT) region including a maximum CT of 71.5 / √(t) to 100 / √(t), and when the glass article is fractured with sample dimensions of 5.08 cm × 5.08 cm (2 inches × 2 inches) square, the glass article fractures into more than 2 fragments / glass article square inch.

[0208] Embodiment 2 The glass article according to Embodiment 1, wherein the concentration of the metal oxide is not zero and varies along the entire thickness.

[0209] Embodiment 3 The glass article according to Embodiment 1 or 2, wherein the monovalent ions of the metal oxide generate stress along the thickness range.

[0210] Embodiment 4 The glass article according to any one of the previous embodiments, wherein the concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface, and increases from that value to the second surface.

[0211] Embodiment 5 The glass article according to any one of the previous embodiments, further comprising a surface compressive stress (CS) of about 300 MPa or more.

[0212] Embodiment 6 The glass article according to Embodiment 5, wherein the surface CS is about 400 MPa or more.

[0213] Embodiment 7 The glass article according to any one of the previous embodiments, wherein the concentration of the metal oxide is about 0.05 mol% or more throughout the thickness.

[0214] Embodiment 8 The glass article according to any one of the previous embodiments, wherein the concentration of the metal oxide at the first surface is about 1.5 times greater than the concentration of the metal oxide at a depth corresponding to about 0.5·t.

[0215] Embodiment 9 The glass article according to any one of the previous embodiments, wherein the glass article comprises a total concentration of metal oxide within the range of about 1 mol% to about 15 mol%.

[0216] Embodiment 10 The glass article according to any one of the previous embodiments, wherein the metal oxide comprises any one or two or more of Li2O, Na2O, K2O, Rb2O, and Cs2O.

[0217] Embodiment 11 Furthermore, a glass article according to any one of the previous embodiments, comprising a surface CS of about 200 MPa or more and a chemical depth of the layer of about 0.4·t or more.

[0218] Embodiment 12 Furthermore, a glass article according to any one of the previous embodiments, comprising CS spreading from the first surface to the DOC, where the DOC is about 0.1·t or more.

[0219] Embodiment 13 A glass article according to any one of the previous embodiments, wherein the CT region contains a metal oxide.

[0220] Embodiment 14 A glass article according to Embodiment 11, wherein the ratio of the maximum CT to the absolute value of the surface CS is in the range of about 0.1 to about 0.8.

[0221] Embodiment 15 A glass article according to any one of the previous embodiments, wherein t includes about 3 millimeters or less.

[0222] Embodiment 16 Furthermore, a glass article according to any one of the previous embodiments, further comprising an amorphous structure.

[0223] Embodiment 17 Furthermore, a glass article according to Embodiments 1 to 15, further comprising a crystalline structure.

[0224] Embodiment 18 Furthermore, a glass article according to any one of the previous embodiments, showing a transmittance of about 88% or more over a wavelength range of about 380 nm to about 780 nm.

[0225] Embodiment 19 Furthermore, a glass article according to any one of the previous embodiments, showing CIELAB color space coordinates under a CIE emitter F02 with an L* value of about 88 or more, an a* value in the range of about -3 to about +3, and a b* value in the range of about -6 to about +6.

[0226] Embodiment 20 Furthermore, comprising a first metal oxide concentration and a second metal oxide concentration, The first metal oxide concentration is in the range of about 0 mol% to about 15 mol% from a first thickness range of about 0·t to about 0.5·t, The second metal oxide concentration is in the range of about 0 mol% to about 10 mol% from a second thickness range of about 0 micrometers to about 25 micrometers. A glass article according to any one of the previous embodiments.

[0227] Embodiment 21 Furthermore, a glass article according to Embodiment 20, comprising a third metal oxide.

[0228] Embodiment 22 Furthermore, a glass article according to any one of the previous embodiments, having a Young's modulus of about 70 GPa or more.

[0229] Embodiment 23 Furthermore, a glass article according to any one of the previous embodiments, comprising a liquid phase viscosity of less than about 100 kilopascals (kPa).

[0230] Embodiment 24 Furthermore, A composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, A composition containing about 4 mol% or less of Na2O, A composition containing any one or two or more of B2O3 and ZnO, and A composition substantially free of P2O5 A glass article according to any one of the previous embodiments, containing any one or two or more of them.

[0231] Embodiment 25 A housing having a front, a back, and sides, and an electrical component at least partially inside the housing, and a display at or near the front of the housing, and a cover substrate disposed on the display, the device comprising: the cover substrate includes a glass-based article according to any one of Embodiments 1 to 24, a device.

[0232] Embodiment 26 A glass-based article including a first surface defining a thickness (t) of about 3 millimeters or less and a second surface facing the first surface, the stress profile spreading along the thickness spreading, all points of the stress profile between the thickness ranges of about 0·t to 0.3·t and exceeding 0.7·t have a tangent having an absolute value slope exceeding about 0.1 MPa / micrometer, the stress profile has a maximum CS, DOC, and a maximum CT within the range of about 71.5 / √(t) to about 100 / √(t), and the ratio of the maximum CT to the absolute value of the maximum CS is within the range of about 0.01 to about 0.2, DOC is about 0.1·t or more, When the glass-based article is broken with a sample size of 5.08 cm × 5.08 cm (2 inches × 2 inches) square, the glass-based article is broken into at least 2 fragments / inch2, a glass-based article.

[0233] Embodiment 27 Furthermore, having a surface CS of about 300 MPa or more, the glass-based article according to Embodiment 26.

[0234] Embodiment 28 Furthermore, having a surface CS of about 200 MPa or more and a chemical depth of a layer of about 0.4·t or more, the glass-based article according to Embodiment 26 or 27.

[0235] Embodiment 29 Furthermore, a glass article according to any one of Embodiments 26 to 28, including a CS layer extending from the first surface to the DOC, where the DOC is 0.1·t or more.

[0236] Embodiment 30 Furthermore, a glass article according to any one of Embodiments 26 to 29, including a CT region having a non-zero and varying metal oxide concentration.

[0237] Embodiment 31 Furthermore, a glass article according to any one of Embodiments 26 to 30, having a ratio of maximum CT to the absolute value of surface CS within the range of about 0.1 to about 0.8.

[0238] Embodiment 32 Furthermore, a glass article according to any one of Embodiments 26 to 31, having a Young's modulus of 70 GPa or more.

[0239] Embodiment 33 Furthermore, a glass article according to any one of Embodiments 26 to 32, having a liquid phase viscosity of less than about 100 kP.

[0240] Embodiment 34 Furthermore, a composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, a composition containing about 4 mol% or less of Na2O, a composition containing any one or two or more of B2O3 and ZnO, and a composition substantially free of P2O5 A glass article according to any one of Embodiments 26 to 33, containing any one or two or more of the above.

[0241] Embodiment 35 A housing having a front surface, a back surface, and side surfaces, and an electrical component at least partially inside the housing, and a display at or near the front surface of the housing A device comprising a cover substrate disposed on a display, The device, wherein the cover substrate includes a glass-based article according to any one of Embodiments 26 to 34.

[0242] Embodiment 36 Including a first surface defining a thickness (t) and a second surface facing the first surface, Having a concentration of metal oxide that is non-zero and varies along a thickness range of about 0·t to about 0.3·t, Having a surface compressive stress of about 200 MPa or more, A glass-based article having a CT region having a maximum CT within the range of about 71.5 / √(t) to about 100 / √(t).

[0243] Embodiment 37 The glass-based article according to Embodiment 36, wherein the thickness range of the metal oxide concentration is about 0·t to about 0.4·t.

[0244] Embodiment 38 The glass-based article according to Embodiment 36 or 37, wherein the thickness range of the metal oxide concentration is about 0·t to about 0.45·t.

[0245] Embodiment 39 The glass-based article according to any one of Embodiments 36 to 38, wherein the monovalent ions of the metal oxide generate stress along the thickness range.

[0246] Embodiment 40 The glass-based article according to Embodiment 39, wherein the monovalent ions of the metal oxide have the largest ionic diameter among all the monovalent ions of the metal oxide in the glass-based substrate.

[0247] Embodiment 41 The glass-based article according to any one of Embodiments 36 to 40, wherein the concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface and increases from that value to the second surface.

[0248] Embodiment 42 When the glass article is broken with the sample size being a 5.08 cm × 5.08 cm (2 inch × 2 inch) square, the glass article is broken into at least 1 fragment / inch² to 40 fragments / inch², the glass article according to any one of Embodiments 36 to 41.

[0249] Embodiment 43 The glass article has a sodium or potassium ion diffusivity of about 450 μm 2 / hour or more and a DOC exceeding about 0.15·t, and the surface CS is 1.5 times or more of the maximum CT, the glass article according to any one of Embodiments 36 to 42.

[0250] Embodiment 44 The glass article has a fracture toughness (K1C) of about 0.65 MPa·m 1 / 2 or more, the glass article according to any one of Embodiments 36 to 43.

[0251] Embodiment 45 The surface CS is greater than the maximum CT, the glass article according to any one of Embodiments 36 to 44.

[0252] Embodiment 46 The surface CS is about 300 MPa or more and the thickness is about 2 millimeters or less, the glass article according to any one of Embodiments 36 to 45.

[0253] Embodiment 47 The concentration of the metal oxide is about 0.05 mol% or more over the entire thickness, the glass article according to any one of Embodiments 36 to 46.

[0254] Embodiment 48 The concentration of the metal oxide on the first surface is about 1.5 times greater than the concentration of the metal oxide at a depth corresponding to about 0.5·t, the glass article according to any one of Embodiments 36 to 47.

[0255] Embodiment 49 The glass article according to any one of Embodiments 36 to 48, wherein the total concentration of the metal oxide is in the range of about 1 mol% to about 15 mol%.

[0256] Embodiment 50 Furthermore, the glass article according to any one of Embodiments 36 to 49, having a chemical depth of a layer of about 0.4·t or more.

[0257] Embodiment 51 Furthermore, the glass article according to any one of Embodiments 36 to 50, including a CS layer extending from the first surface to the DOC, and the DOC is about 0.1·t or more.

[0258] Embodiment 52 The glass article according to any one of Embodiments 36 to 51, wherein the CT region contains a metal oxide.

[0259] Embodiment 53 The glass article according to any one of Embodiments 36 to 52, wherein the ratio of the maximum CT to the absolute value of the surface CS is in the range of about 0.1 to about 0.8.

[0260] Embodiment 54 The glass article according to any one of Embodiments 36 to 53, wherein t includes about 3 millimeters or less.

[0261] Embodiment 55 Furthermore, the glass article according to any one of Embodiments 36 to 54, having a Young's modulus of about 70 GPa or more.

[0262] Embodiment 56 Furthermore, the glass article according to any one of Embodiments 36 to 55, having a liquid-phase viscosity of less than about 100 kP.

[0263] Embodiment 57 Furthermore, a composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, a composition containing about 4 mol% or less of Na2O, A composition containing any one or two or more of B2O3 and ZnO, and A composition substantially free of P2O5 A glass article according to any one of Embodiments 36 to 56, containing any one or two or more of the above.

[0264] Embodiment 58 A housing having a front surface, a back surface, and side surfaces, and An electrical component at least partially inside the housing, and A display on or near the front surface of the housing, and A device comprising a cover substrate disposed on the display, the cover substrate containing a glass article according to any one of Embodiments 36 to 57.

[0265] Embodiment 59 A glass article including a first surface defining a thickness (t) and a second surface facing the first surface, and containing a metal oxide forming a concentration gradient, The concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface, and increases from that value to the second surface, The concentration of the metal oxide at that point is not zero, The glass article has a storage tensile energy of more than about 0 J / m 2 and less than 20 J / m 2 and a Young's modulus of about 70 GPa or more.

[0266] Embodiment 60 Furthermore, the glass article according to Embodiment 59, having a surface CS of about 300 MPa or more.

[0267] Embodiment 61 The glass article according to Embodiment 59 or 60, wherein the concentration of the metal oxide is about 0.05 mol% or more over the entire thickness.

[0268] Embodiment 62 The glass article according to any one of Embodiments 59 to 61, wherein the concentration of the metal oxide on the first surface is about 1.5 times greater than the concentration of the metal oxide at a depth corresponding to about 0.5·t.

[0269] Embodiment 63 The glass article according to any one of Embodiments 59 to 62, wherein the total concentration of the metal oxide is in the range of about 1 mol% to about 15 mol%.

[0270] Embodiment 64 The glass article according to any one of Embodiments 59 to 63, wherein the metal oxide contains any one or more of Li2O, Na2O, K2O, Rb2O, and Cs2O.

[0271] Embodiment 65 Furthermore, the glass article according to any one of Embodiments 59 to 64, including a CS layer extending from the first surface to the DOC, and the DOC is about 0.1·t or more.

[0272] Embodiment 66 Furthermore, the glass article according to any one of Embodiments 59 to 65, having a CT region with a metal oxide concentration gradient.

[0273] Embodiment 67 The glass article according to Embodiment 66, wherein the CT region has a maximum CT, and the ratio of the maximum CT to the absolute value of the surface CS is in the range of about 0.1 to about 0.8.

[0274] Embodiment 68 The glass article according to any one of Embodiments 59 to 67, wherein t includes about 3 millimeters or less.

[0275] Embodiment 69 The glass article according to Embodiment 67, wherein the maximum CT is in the range of about 71.5 / √(t) to about 100 / √(t).

[0276] Embodiment 70 Furthermore, a glass article according to any one of Embodiments 59 to 69, having a liquid-phase viscosity of less than about 100 kP.

[0277] Embodiment 71 Furthermore, a composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, a composition containing about 4 mol% or less of Na2O, a composition containing any one or two or more of B2O3 and ZnO, and a composition substantially free of P2O5 A glass article according to any one of Embodiments 59 to 70, containing any one or two or more of the above.

[0278] Embodiment 72 A device comprising a housing having a front surface, a back surface and side surfaces, an electrical component at least partially inside the housing, a display in front of or near the front surface of the housing, and a cover substrate disposed on the display, the cover substrate including a glass article according to any one of Embodiments 59 to 71.

[0279] Embodiment 73 A glass article including a first surface defining a thickness (t) of about 3 millimeters or less and a second surface opposite the first surface, having a stress profile extending along the thickness, wherein the stress profile has a tangent with an absolute value slope exceeding about 0.1 MPa / micrometer at all points between a thickness range from about 0·t to 0.3·t and exceeding 0.7·t, the stress profile having a maximum CS, DOC and maximum CT, the ratio of the maximum CT to the absolute value of the maximum CS being in the range of about 0.01 to about 0.2, DOC being about 0.1·t or more, the glass article having a value exceeding about 0 J / m 2 and less than 20 J / m 2A glass article having a storage tensile energy of less than and a Young's modulus of about 70 GPa or more.

[0280] Embodiment 74 Furthermore, the glass article according to Embodiment 73, having a non-zero concentration of metal oxide that continuously varies along the entire thickness.

[0281] Embodiment 75 Furthermore, the glass article according to Embodiment 73 or 74, having a non-zero concentration of metal oxide that continuously varies along a thickness portion of less than about 10 micrometers.

[0282] Embodiment 76 The glass article according to any one of Embodiments 73 to 75, wherein the maximum CS includes about 300 MPa or more.

[0283] Embodiment 77 Furthermore, the glass article according to any one of Embodiments 73 to 76, having a chemical depth of a layer of about 0.4·t or more.

[0284] Embodiment 78 Furthermore, the glass article according to any one of Embodiments 73 to 77, having a CT region with a metal oxide concentration gradient.

[0285] Embodiment 79 The glass article according to any one of Embodiments 73 to 78, wherein t includes about 3 millimeters or less.

[0286] Embodiment 80 The glass article according to any one of Embodiments 73 to 79, wherein the maximum CT is 71.5 / √(t) or more.

[0287] Embodiment 81 Furthermore, the glass article according to any one of Embodiments 73 to 80, having a liquid phase viscosity of less than about 100 kP.

[0288] Embodiment 82 Furthermore, A composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, A composition containing about 4 mol% or less of Na2O, A composition containing any one or more of B2O3 and ZnO, and A composition substantially free of P2O5 A glass article according to any one of Embodiments 73 to 81, comprising any one or more of the above.

[0289] Embodiment 83 A housing having a front, a back, and sides, and An electrical component at least partially inside the housing, and A display at or near the front of the housing, and A device comprising a cover substrate disposed on the display, the cover substrate comprising a glass article according to any one of Embodiments 73 to 82.

[0290] Embodiment 84 A glass article having a stress profile including a CS region and a CT region, wherein the CT region is given by the formula: Stress(x) = MaxT - (((CTn·(n + 1)) / 0.5n)·|(x / t) - 0.5|n) (where MaxT is the maximum tensile value, CTn is a positive value in MPa units that is less than or equal to MaxT, x is the position along the thickness (t) in micrometers, and n is between 1.5 and 5.) A glass article estimated by the above.

[0291] Embodiment 85 The glass article according to Embodiment 84, wherein the CT region has a maximum CT value in the range of about 50 MPa to about 250 MPa, and the maximum CT value is at a depth in the range of about 0.4·t to about 0.6t.

[0292] Embodiment 86 A glass article according to embodiment 84 or 85, wherein the stress profile has a slope within the range of about 20 MPa / micrometer to about 200 MPa / micrometer from a thickness within the range of about 0·t to about 0.1·t micrometers.

[0293] Embodiment 87 A glass article according to any one of embodiments 84 to 86, wherein the stress profile is approximated by a plurality of error functions measured from 0.5·t to the surface.

[0294] Embodiment 88 Use of a glass substrate in a toughened glass article, wherein the glass substrate has, in (mol%): an amount of SiO2 within the range of about 68 to about 75, an amount of Al2O3 within the range of about 10 to about 15, an amount of B2O3 within the range of about 0.5 to about 5, an amount of Li2O within the range of about 2 to about 10, an amount of Na2O within the range of about 0 to about 6, an amount of MgO within the range of about 1 to about 4, an amount of ZnO within the range of about 0 to about 3, and an amount of CaO within the range of about 0 to about 5, the glass substrate is ion-exchangeable and amorphous, the glass substrate has a ratio of Li2O to R2O within the range of about 0.45 to about 1, a difference between the total amount of R2O and the amount of Al2O3 within the range of about -5 to about 0, a difference between the total amount of RxO (mol%) and the amount of Al2O3 within the range of about 0 to about 3, and a ratio of the amount of MgO (mol%) to the total amount of RO (mol%) within the range of about 0 to about 1 indicating any one or two or more of use wherein the glass substrate is substantially free of nucleating agents.

[0295] Embodiment 89 in mol% an amount of SiO2 within the range of about 68 to about 75, An amount of Al2O3 in the range of about 10 to about 15, An amount of B2O3 in the range of about 0.5 to about 5, An amount of Li2O in the range of about 2 to about 10, An amount of Na2O in the range of about 0 to about 6, An amount of MgO in the range of about 1 to about 4, An amount of ZnO in the range of about 0 to about 3, and An amount of CaO in the range of about 0 to about 5 A glass substrate having a composition containing The glass substrate is ion-exchangeable and amorphous, The glass substrate The ratio of Li2O to R2O in the range of about 0.45 to about 1, The difference between the total amount of R2O and the amount of Al2O3 in the range of about -5 to about 0, The difference between the total amount of RxO (mol%) and the amount of Al2O3 in the range of about 0 to about 3, and The ratio of the amount of MgO (mol%) to the total amount of RO (mol%) in the range of about 0 to about 1 Indicates any one or two or more of A glass substrate in which the glass substrate substantially does not contain a nucleating agent.

[0296] Embodiment 90 In mol%, An amount of SiO2 in the range of about 68 to about 75, An amount of Al2O3 in the range of about 10 to about 15, An amount of B2O3 in the range of about 0.5 to about 5, An amount of Li2O in the range of about 2 to about 10, An amount of Na2O in the range of about 0 to about 6, An amount of MgO in the range of about 1 to about 4, An amount of ZnO in the range of about 0 to about 3, and An amount of CaO in the range of about 0 to about 5 A glass substrate having a composition containing The glass substrate is amorphous and strengthened, The Na2O concentration varies, and the glass substrate substantially does not contain a nucleating agent. A glass substrate.

[0297] Embodiment 91 Furthermore, the ratio of Li2O to R2O within the range of about 0.45 to about 1, the difference between the total amount of R2O and the amount of Al2O3 within the range of about -5 to about 0, the difference between the total amount of RxO (mol%) and the amount of Al2O3 within the range of about 0 to about 3, and the ratio of the amount of MgO (mol%) to the total amount of RO (mol%) within the range of about 0 to about 1 The glass substrate according to Embodiment 90, which exhibits any one or two or more of the above.

[0298] Embodiment 92 The glass article according to any one of Embodiments 1 to 88, wherein the Vickers scratch threshold of at least one of the first surface and the second surface is greater than 7 N.

[0299] Embodiment 93 The glass article according to any one of Embodiments 1 to 88 and 92, wherein the Vickers scratch threshold of at least one of the first surface and the second surface is less than 14 N.

[0300] Embodiment 94 On a 30 grit sandpaper disposed on the surface of the glass so that a 100 μm gap is formed between the sandpaper and the surface of the glass, from one of the heights of (i) about 80 cm, (ii) about 88 cm, (iii) about 90 cm, and (iv) about 95 cm, when an inverted ball drop test is performed using a 4.2 g stainless steel ball having a diameter of 10 mm, the toughened glass substrate has either (i) a survival rate of at least 60% or (ii) a survival rate of at least 80%, and the survival rate is based on tests of at least five samples. The glass article according to any one of Embodiments 1 to 88 and 92 to 93.

[0301] Embodiment 95 An inverted ball drop test was performed using a 4.2 g stainless steel ball having a diameter of 10 mm on 30 grit sandpaper disposed on the surface of glass such that a 100 μm gap was formed between the sandpaper and the surface of the glass. When the test was performed, the strengthened glass-based substrate had an average defect height of one of (i) over 70 cm, (ii) over 75 cm, (iii) over 80 cm, and (iv) over 85 cm, and the survival rate is based on tests of at least five samples. A glass-based article according to any one of Embodiments 1 to 88 and 92 to 94.

[0302] Hereinafter, preferred embodiments of the present invention will be described item by item.

[0303] Embodiment 1 Including a first surface defining a thickness (t) and a second surface facing the first surface, Having a concentration of metal oxide that is non-zero and varies along a thickness range of about 0·t to about 0.3·t, Having a surface compressive stress of about 200 MPa or more, A glass-based article having a CT region having a maximum CT within the range of about 71.5 / √(t) to about 100 / √(t).

[0304] Embodiment 2 The glass-based article according to Embodiment 1, wherein the thickness range of the metal oxide concentration is about 0·t to about 0.4·t.

[0305] Embodiment 3 The glass-based article according to Embodiment 1 or 2, wherein the thickness range of the metal oxide concentration is about 0·t to about 0.45·t.

[0306] Embodiment 4 The glass-based article according to any one of Embodiments 1 to 3, wherein the monovalent ions of the metal oxide generate stress along the thickness range.

[0307] Embodiment 5 The glass article according to Embodiment 4, wherein the monovalent ion of the metal oxide has the largest ion diameter among all the monovalent ions of the metal oxide in the glass substrate.

[0308] Embodiment 6 The glass article according to any one of Embodiments 1 to 5, wherein the concentration of the metal oxide decreases from the first surface to a value at a point between the first surface and the second surface and increases from that value to the second surface.

[0309] Embodiment 7 The glass article according to any one of Embodiments 1 to 6, wherein when the glass article is broken with a sample size of 5.08 cm × 5.08 cm square, the glass article is broken into at least 1 fragment / inch² to 40 fragments / inch².

[0310] Embodiment 8 The glass article has sodium or potassium ion diffusivity of about 450 μm 2 / hour or more and DOC exceeding about 0.15·t, and surface CS is 1.5 times or more of maximum CT. The glass article according to any one of Embodiments 1 to 7.

[0311] Embodiment 9 The glass article has a fracture toughness (K1C) of about 0.65 MPa·m 1 / 2 or more. The glass article according to any one of Embodiments 1 to 8.

[0312] Embodiment 10 The glass article according to any one of Embodiments 1 to 9, wherein surface CS is larger than maximum CT.

[0313] Embodiment 11 The glass article according to any one of Embodiments 1 to 10, wherein surface CS is about 300 MPa or more and the thickness is about 2 millimeters or less.

[0314] Embodiment 12 The glass article according to any one of Embodiments 1 to 11, wherein the concentration of the metal oxide is 0.05 mol% or more throughout the thickness.

[0315] Embodiment 13 The glass article according to any one of Embodiments 1 to 12, wherein the concentration of the metal oxide on the first surface is about 1.5 times greater than the concentration of the metal oxide at a depth corresponding to about 0.5·t.

[0316] Embodiment 14 The glass article according to any one of Embodiments 1 to 13, wherein the total concentration of the metal oxide is in the range of about 1 mol% to about 15 mol%.

[0317] Embodiment 15 Furthermore, the glass article according to any one of Embodiments 1 to 14, which has a chemical depth of a layer of about 0.4·t or more.

[0318] Embodiment 16 Furthermore, the glass article according to any one of Embodiments 1 to 15, which includes a CS layer extending from the first surface to the DOC, and the DOC is about 0.1·t or more.

[0319] Embodiment 17 The glass article according to any one of Embodiments 1 to 16, wherein the CT region contains a metal oxide.

[0320] Embodiment 18 The glass article according to any one of Embodiments 1 to 17, wherein the ratio of the maximum CT to the absolute value of the surface CS is in the range of about 0.1 to about 0.8.

[0321] Embodiment 19 The glass article according to any one of Embodiments 1 to 18, wherein t includes about 3 millimeters or less.

[0322] Embodiment 20 Furthermore, the glass article according to any one of Embodiments 1 to 19, which has a Young's modulus of about 70 GPa or more.

[0323] Embodiment 21 Furthermore, a glass article according to any one of Embodiments 1 to 20, having a liquid-phase viscosity of less than about 100 kP.

[0324] Embodiment 22 Furthermore, a composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, a composition containing about 4 mol% or less of Na2O, a composition containing any one or two or more of B2O3 and ZnO, and a composition substantially free of P2O5 A glass article according to any one of Embodiments 1 to 21, containing any one or two or more of the above.

[0325] Embodiment 23 A housing having a front surface, a back surface, and side surfaces, an electrical component at least partially inside the housing, a display in front of or near the front surface of the housing, A device comprising a cover substrate disposed on the display, wherein the cover substrate contains a glass article according to any one of Embodiments 1 to 22.

[0326] Embodiment 24 A glass article including a first surface defining a thickness (t) of about 3 millimeters or less and a second surface facing the first surface, having a stress profile extending along the thickness, wherein the stress profile has a tangent with an absolute value slope exceeding about 0.1 MPa / micrometer at all points between a thickness range from about 0·t to 0.3·t and exceeding 0.7·t, the stress profile has a maximum CS, DOC, and maximum CT, the ratio of the maximum CT to the absolute value of the maximum CS is in the range of about 0.01 to about 0.2, and DOC is about 0.1·t or more, the glass article has an amount exceeding about 0 J / m 2 and less than 20 J / m 2A glass article having a storage tensile energy of less than and a Young's modulus of about 70 GPa or more.

[0327] Embodiment 25 Furthermore, the glass article according to Embodiment 24, having a non-zero concentration of metal oxide that continuously changes along the entire thickness.

[0328] Embodiment 26 Furthermore, the glass article according to Embodiment 24 or 25, having a non-zero concentration of metal oxide that continuously changes along a thickness portion of less than about 10 micrometers.

[0329] Embodiment 27 The glass article according to any one of Embodiments 24 to 26, wherein the maximum CS includes about 300 MPa or more.

[0330] Embodiment 28 Furthermore, the glass article according to any one of Embodiments 24 to 27, having a chemical depth of a layer of about 0.4·t or more.

[0331] Embodiment 29 Furthermore, the glass article according to any one of Embodiments 24 to 28, having a CT region with a metal oxide concentration gradient.

[0332] Embodiment 30 The glass article according to any one of Embodiments 24 to 29, wherein t includes about 3 millimeters or less.

[0333] Embodiment 31 The glass article according to any one of Embodiments 24 to 30, wherein the maximum CT is 71.5 / √(t) or more.

[0334] Embodiment 32 Furthermore, the glass article according to any one of Embodiments 24 to 31, having a liquid-phase viscosity of less than about 100 kP.

[0335] Embodiment 33 Furthermore, A composition having a combined amount of Al2O3 and Na2O of about 17 mol% or less, A composition containing about 4 mol% or less of Na2O, A composition containing any one or two or more of B2O3 and ZnO, and A composition substantially free of P2O5 A glass article according to any one of Embodiments 24 to 32, containing any one or two or more of the above.

[0336] Embodiment 34 A housing having a front surface, a back surface, and side surfaces, and An electrical component at least partially inside the housing, and A display at or near the front surface of the housing, and A device comprising a cover substrate disposed on the display, wherein the cover substrate contains the glass article according to any one of Embodiments 24 to 33.

[0337] Embodiment 35 A glass article according to any one of Embodiments 1 to 34, wherein the Vickers scratch threshold of at least one of the first surface and the second surface is greater than 7 N.

[0338] Embodiment 36 A glass article according to any one of Embodiments 1 to 35, wherein the Vickers scratch threshold of at least one of the first surface and the second surface is less than 14 N.

[0339] Embodiment 37 On a 30 grit sandpaper disposed on the surface of a glass such that a 100 μm gap is formed between the sandpaper and the surface of the glass, when an inverted ball drop test is performed using a 4.2 g stainless steel ball having a diameter of 10 mm from one of the heights of (i) about 80 cm, (ii) about 88 cm, (iii) about 90 cm, and (iv) about 95 cm, the strengthened glass-based substrate has either (i) a survival rate of at least 60% or (ii) a survival rate of at least 80%, and the survival rate is based on tests of at least five samples. The glass-based article according to any one of Embodiments 1 to 36 Embodiment 38 On a 30 grit sandpaper disposed on the surface of a glass such that a 100 μm gap is formed between the sandpaper and the surface of the glass, when an inverted ball drop test is performed using a 4.2 g stainless steel ball having a diameter of 10 mm, the strengthened glass-based substrate has an average defect height of one of the heights exceeding (i) 70 cm, (ii) 75 cm, (iii) 80 cm, and (iv) 85 cm, and the survival rate is based on tests of at least five samples. The glass-based article according to any one of Embodiments 1 to 37

Description of Reference Numerals

[0340] 100 Glass article 101 First surface 110 Surface CS 120 Central tension (CT) 130 Depth of compression (DOC) 200 Glass-based article 201 First surface 210 Surface CS 220 Maximum CT 230 DOC 300 Glass-based article 302 First surface 304 Second surface 310 Surface CS 312 Stress profile 315 CS layer 317, 327 Depth or length 320 Maximum CT 325 CT Layers 330 DOC 400 AROR Configuration 410 Abrasive Glass Articles 430 Load Ring 420 Support Ring 430a Surface 500 Device 510 Test Stand 512 Solid Base 514 Sheet 515 Sample Holder 516 Gap 518 Glass Articles 520 Adhesive Tape 530 Ball 1000 Electronic Equipment 1020 Housing 1040 Front 1060 Back 1080 Side 1120 Display

Claims

Claim 1 SiO of 40 mol% or more and 80 mol% or less ２ and Na of 0 mol% or more and 6 mol% or less ２ O, and Glass article containing less than 2 mol% of K ２ O, and having a first surface defining the thickness (t) of the glass article and a second surface opposite the first surface, Li in the glass article ２ O, Na ２ O and K ２ When the total of O is defined as R ２ O, the ratio of Li ２ O (mol%) to R ２ O (mol%) is 0.7 or more and 1.0 or less, having a stress profile of surface compressive stress (CS) and maximum central tension (CT), wherein the maximum central tension CT is 80 MPa or more and 95 MPa or less, the maximum central tension CT is located within the glass article in the range of 0.4t or more and 0.6·t or less, the surface compressive stress CS is 200 MPa or more, the depth of compression (DOC) is 0.14·t or more and 0.25·t or less, a glass article that is a glass-ceramic containing an amorphous phase and a crystalline phase. Claim 2 The glass article contains 4 mol% or less of Na ２ O, and the glass article according to claim 1. Claim 3 The glass article contains less than 1 mol% of K ２ O, the glass article according to claim 1 or 2. Claim 4 The glass article contains 0 mol% or more and 5 mol% or less of ZrO ２ The glass article according to any one of claims 1 to 3, inclusive. Claim 5 The glass article contains 67 mol% or more and 75 mol% or less of SiO ２ The glass article according to any one of claims 1 to 4, containing the same. Claim 6 The glass article according to any one of claims 1 to 5, wherein the glass article is strengthened by an ion exchange process that provides the stress profile. Claim 7 The glass article according to any one of claims 1 to 6, wherein the ratio of CT to CS of the glass article is in the range of 0.1 to 0.

8. Claim 8 The glass article according to any one of claims 1 to 7, wherein the glass article has a thickness of 1 mm or less.

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