Three-step ion exchange (TIOX) method for glass strengthening with improved stress profiles

Abstract

Glass articles having high surface compressive stress (CS) and high CS-integrated area are provided. Methods of making such articles include chemical ion exchange processes.

Description

SP23-267 THREE-STEP ION EXCHANGE (TIOX) METHOD FOR GLASS STRENGTHENING WITH IMPROVED STRESS PROFILES BACKGROUNDCross-Reference To Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63 / 600302 filed on November 17, 2023 and U.S. Provisional Application Serial No. 63 / 539900 filed on September 22, 2023, the contents of each of which are relied upon and incorporated herein by reference in their entireties. Field

[0002] This disclosure relates to glass articles having high surface compressive stress (CS) and high CS-integrated area, as well as to chemical ion exchange processes to prepare such glass articles. Technical Background

[0003] Designs of devices in the consumer electronics market continue to evolve. Designs that include 2.5D and 3D configurations are becoming more common as these features improve aesthetics of the devices. Handheld devices such as phones and tablets, and heavier consumer electronic devices such as headsets, other applications such as automotive interior displays, complex devices such as bendable phones, having 2.5D or 3D cover glasses are prone to impact events, which can introduce flaws. Impact events are a common cause of failure for the cover glass. To combat this failure mode, typically compressive stresses are added to a surface of the cover glass to help resist damage and failure. Depth of damage is related to depth of compressive stress with respect to survivability in these events.

[0004] Chemical treatment is a strengthening method to impart a desired and / or engineered stress profile in a glass article, such as a cover glass, the stress profile having one or more of the following parameters: compressive stress (CS), depth of compression (DOC), and maximum central tension (CT). Many glass articles,SP23-267 including those with engineered stress profiles, have a compressive stress that is highest or at a peak at the glass surface and reduces from a peak value moving away from the surface into the depth of the article, and there is zero stress at some interior location of the glass article before the stress in the glass article becomes tensile. Chemical strengthening by ion exchange (IOX) of alkali-containing glass is a proven methodology in this field.

[0005] It has been a continuous effort for glass makers and handheld and consumer device manufacturers to improve protection of glass-containing devices from strong impacts. SUMMARY

[0006] Aspects of the disclosure pertain to glass articles having various configurations including traditional 2D (planar), 2.5D, and 3D, and methods of making the same. Traditional 2D configurations are those glasses considered totally flat with no edge or a 90 degree edge. Reference to 2.5D configurations herein means those glasses having curvature, usually considered slight curvature, at the edges. As to 3D configurations, those glasses have curvature, usually significant, at any location. Such glass articles are used, for example, in consumer devices and automotive interiors.

[0007] In an aspect, a glass article comprises: opposing first and second surfaces defining a body of the article having a thickness (t); a stress profile of the body comprising: a spike region extending from the first surface to a knee located at a depth of layer (DOL); a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa, or 1100 MPa, or 1200 MPa, or 1300 MPa, or 1400 MPa; a tail region extending from the knee to a center of the glass article as well as having a central tension (CT) and a depth of compression (DOC). The articles have a high compressive stress extended over a depth range, such that a compressive stress integral over depths above 5 microns and extending to progressively higher depths, up to 12, 15, 20, 25, and even 30 microns, stay above a value that corresponds to a substantially improved probability of surviving high-stress impact events by offering significantly improved retained strength or failure stress in that depth range as compared to prior-art compressive-stress profiles. In one or more implementations,SP23-267 the compressive stress integral at a depth of 5 micrometers is greater than or equal to 5.2 MPa^millimeter.

[0008] In an aspect, a glass article comprises: opposing first and second surfaces defining a body of the article having a thickness (t) of greater than or equal to 0.70 millimeters to less than or equal to 1.3 millimeters; a stress profile of the body comprising: a spike region extending from the first surface to a knee located at a depth of layer (DOL) of greater than or equal to 20 micrometers; a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa, or 1100 MPa, or 1200 MPa, or 1300 MPa, or 1400 MPa; and a tail region extending from the knee to a center of the glass article as well as having a central tension (CT) and a depth of compression (DOC), the DOC being greater than or equal to 25 micrometers.

[0009] In an aspect, a method of making a glass article, which has opposing first and second surfaces defining a body having a thickness (t), comprises: exposing a glass substrate that contains an alkali metal oxide in a base composition to a first ion exchange (IOX-1) treatment including a first bath comprising one or more molten potassium salts for a first duration at a first temperature that is less than a strain point of the glass substrate; following the IOX-1, exposing the glass substrate to a second ion exchange (IOX-2) treatment including a second bath comprising an admixture of ion-exchangeable molten salts and optional scavenging additive for a second duration that is less than the first duration at a second temperature that is greater than or equal to the first temperature and less than the strain point; and following the IOX-2, exposing the glass substrate to a third ion exchange (IOX-3) treatment including a third bath comprising one or more molten potassium salts for a third duration that is less than the first duration at a third temperature that is less than the first temperature.

[0010] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the implementations described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0011] It is to be understood that both the foregoing general description and the following detailed description describe various implementations and are intended toSP23-267 provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various implementations, and are incorporated into and constitute a part of this specification. The drawings illustrate the various implementations described herein, and together with the description serve to explain the principles and operations of the claimed subject matter. BRIEFDESCRIPTION OF THEDRAWINGS

[0012] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several implementations described below.

[0013] FIG.1 schematically depicts a cross-section of a glass having compressive stress layers on surfaces thereof according to implementations disclosed and described herein;

[0014] FIG.2A is a plan view of an exemplary electronic device incorporating any of the glass articles disclosed herein;

[0015] FIG.2B is a perspective view of the exemplary electronic device of FIG.2A;

[0016] FIG. 3 is an exemplary stress profile across a thickness of a chemically strengthened glass article;

[0017] FIG.4 is another exemplary stress profile across a thickness of a chemically strengthened glass article;

[0018] FIG.5 is a graph of concentration (mole %) versus depth (micrometers) for K2O, Na2O, and Li2O for Example 2-I;

[0019] FIG. 6 is a graph of modeled stress profiles depicting compressive stress (MPa) versus depth (z µm) for various Examples of Table 1;

[0020] FIG. 7 is a graph of compressive stress (MPa) versus thickness (micrometers) for Example 1;

[0021] FIG. 8 is a graph of compressive stress integral (MPa^millimeter) versus thickness (micrometers) for Example 1 based on data of FIG.7;SP23-267

[0022] FIG. 9 is a graph of compressive stress (MPa) versus thickness (micrometers) for Example 2-II;

[0023] FIG. 10 is a graph of compressive stress integral (MPa^millimeter) versus thickness (micrometers) for Example 2-II based on data of FIG.9;

[0024] FIG. 11 is a graph of compressive stress (MPa) versus thickness (micrometers) for Example 3;

[0025] FIG. 12 is a graph of compressive stress integral (MPa^millimeter) versus thickness (micrometers) for Example 3 based on data of FIG.11;

[0026] FIG.13 is Failure Stress (MPa) versus flaw depth (micrometers) for Example 1 and Comparative Example B;

[0027] FIG. 14 is a graph of failure probability (%) versus failure stress (MPa) for Example 1;

[0028] FIG. 15 is a graph of failure probability (%) versus failure stress (MPa) for Example 7;

[0029] FIG.16 is a load-deflection plot for Example 7;

[0030] FIG. 17 is a normalized load-deflection plot for Example 7 with respect to deflection x thickness x elastic modulus; and

[0031] FIG. 18 is an example micrograph of an article according to DIOX-B comparative example herein showing a flaw and its flaw depth that was introduced by pneumatic abrasion, later revealed after ring-on-ring (ROR) testing. DETAILED DESCRIPTION

[0032] Before describing several exemplary implementations, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following disclosure. The disclosure provided herein is capable of other implementations and of being practiced or being carried out in various ways.

[0033] Reference throughout this specification to "one implementation," "certain implementations," "various implementations," "one or more implementations" or "anSP23-267 implementation" means that a particular feature, structure, material, or characteristic described in connection with the implementation is included in at least one implementation of the disclosure. Thus, the appearances of the phrases such as "in one or more implementations," "in certain implementations," "in various implementations," "in one implementation" or "in an implementation" in various places throughout this specification are not necessarily referring to the same implementation, or to only one implementation. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more implementations. Definitions and Measurement Techniques

[0034] The terms "glass article" and "glass substrates" are used to include any object made of glass. Glass substrates according to one or more implementations can be selected from soda-lime silicate glass, alkali-alumino silicate glass, alkali-containing borosilicate glass, alkali-containing aluminoborosilicate glass, and alkali-containing phosphate glass.

[0035] A "base composition" is a chemical make-up of a substrate prior to any ion exchange (IOX) treatment. That is, the base composition is undoped by any ions from IOX. A composition at the center of a glass article that has been IOX treated is typically the same as the base composition when IOX treatment conditions are such that ions supplied for IOX do not diffuse into the center of the substrate. In one or more implementations, a central composition at the center of the glass article comprises the base composition.

[0036] It is noted that the terms "substantially" and "about" may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Thus, for example, a glass article that is "substantially free of MgO" is one in which MgO is not actively added or batched into the glass article, but may be present in very small amounts as a contaminant. As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities andSP23-267 characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range in the specification recites “about,” the numerical value or end-point of a range is intended to include two implementations: one modified by “about,” and one not modified by “about.” It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0037] Unless otherwise specified, all compositions described herein are expressed in terms of mole percent (mol %) on an oxide basis.

[0038] A “stress profile” is stress as a function of thickness across a glass article. A compressive stress region extends from a first surface to a depth of compression (DOC) of the article, and is a region where the article is under compressive stress. A central tension region extends from the DOC to include the region where the article is under tensile stress.

[0039] As used herein, depth of compression (DOC) refers to the depth at which the stress within the glass article changes from compressive to tensile stress. At the DOC, the stress crosses from a positive (compressive) stress to a negative (tensile) stress and thus exhibits a stress value of zero. According to the convention normally used in mechanical arts, compression is expressed as a negative (< 0) stress and tension is expressed as a positive (> 0) stress. Throughout this description, however, positive values of stress are compressive stress (CS), which are expressed as a positive or absolute value – i.e., as recited herein, CS = ½CS½. Additionally, negative values of stress are tensile stress. But when used with the term “tensile”, stress or central tension (CT) may be expressed as a positive value, i.e., CT = ½CT½. Central tension (CT) refers to tensile stress in a central region or a central tension region of the glass article. Maximum central tension (maximum CT or CTmax) may occur in the central tension region nominally at 0.5•t, where t is the article thickness, which allows for variation from exact center of the location of the maximum tensile stress. Peak tensionSP23-267 (PT) refers to maximum tension measured, which may or may not be at the center of the article.

[0040] With reference to FIG. 1, a glass, which includes a glass article, has a thickness t and a first region under compressive stress (e.g., first and second compressive stress layers 120, 122 in FIG.1) extending from the surface to a depth of compression (DOC) of the glass and a second region (e.g., central region 130 in FIG.1) under a tensile stress or central tension (CT) extending from the DOC into the central or interior region of the glass.

[0041] The compressive stress (CS) has a maximum or peak value, which typically occurs at the surface of the glass (but such need not be the case as the peak may occur at a depth from the surface of the glass), and the CS varies with distance d from the surface according to a function. Referring again to FIG.1, the first compressive stress layer 120 extends from first surface 110 to a depth d1 and the second compressive stress layer 122 extends from second surface 112 to a depth d2. Together, these segments define a compression region or CS of glass 100.

[0042] The compressive stress of both compressive stress layers (120, 122 in FIG. 1) is balanced by stored tension in the central region (130) of the glass.

[0043] An exemplary stress profile of a chemically strengthened glass article is illustrated graphically in FIG.3, across a thickness t defined by a first surface 302 and a second surface 304 opposing the first surface of a glass article 300 of one or more implementations. In one or more implementations, the thickness t may be about 3 millimeters or less, including all values and subranges therebetween.

[0044] The stress profile extends from the first surface 302 to the second surface 304 (or along the entire length of the thickness t). In the implementation shown in FIG. 3, the stress profile 312 as measured by SCALP as described herein is illustrated. The y-axis represents the stress value and the x-axis represents the thickness or depth within the glass article. The exemplary stress profile 312 includes a surface CS 310, a maximum CT 320, and a first DOC 330. The stress profile 312 has a CS layer 317 extending from a surface 302 to the first DOC 330. A second CS layer 317 extends from surface 304 to a second DOC 332. The stress profile 312 also has a CT layer 327 extending between the first DOC 330 and the second DOC 332.SP23-267

[0045] A "knee" of a stress profile is a depth of an article where the slope of the stress profile transitions from steep to gradual. See FIG.4, for example. The knee may refer to a transition area over a span of depths where the slope is changing. The knee stress CSk is defined as the value of compressive stress that the deeper portion of the CS profile extrapolates to at the depth of spike (DOLsp). The DOLsp is reported as measured by a surface-stress meter by known methods. FIG.4 shows generally a stress profile of compressive stress versus normalized position showing a spike region, a knee, and a tail region; CSmax, CSk, DOLsp, and DOC.

[0046] A non-zero metal oxide concentration that varies from the first surface to a depth of layer (DOL) with respect to the metal oxide or that varies along at least a substantial portion of the article thickness (t) indicates that a stress has been generated in the article as a result of ion exchange. The variation in metal oxide concentration may be referred to herein as a metal oxide concentration gradient. The metal oxide that is non-zero in concentration and varies from the first surface to a DOL or along a portion of the thickness may be described as generating a stress in the glass article. The concentration gradient or variation of metal oxides is created by chemically strengthening a glass substrate in which a plurality of first metal ions in the glass substrate is exchanged with a plurality of second metal ions.

[0047] As used herein, the terms "depth of exchange", "depth of layer" (DOL), "chemical depth of layer", and "depth of chemical layer" may be used interchangeably, describing in general the depth at which ion exchange facilitated by an ion exchange process (IOX) takes place for a particular ion. DOL refers to the depth within a glass article (i.e., the distance from a surface of the glass article to its interior region) at which an ion of a metal oxide or alkali metal oxide (e.g., the metal ion or alkali metal ion) diffuses into the glass article where the concentration of the ion reaches a minimum value, as determined by Glow Discharge – Optical Emission Spectroscopy (GD-OES)). In some implementations, the DOL is given as the depth of exchange of the slowest-diffusing or largest ion introduced by an ion exchange (IOX) process. DOL with respect to potassium (DOLK) is the depth at which the potassium content of the glass article reaches the potassium content of the underlying substrate. DOL with respect to sodium (DOLNa) is the depth at which the sodium content of the glass article reaches the sodium content of the underlying substrate.SP23-267

[0048] Unless otherwise specified, CT and CS are expressed herein in megaPascals (MPa), thickness is express in millimeters and DOC and DOL are expressed in microns (micrometers).

[0049] Compressive stress (including surface / peak CS, CSmax) are measured by surface stress meter (FSM) using commercially available instruments such as the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. SOC in turn is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16, entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety.

[0050] The maximum central tension (CT) or peak tension (PT) and stress retention values are measured using a scattered light polariscope (SCALP) technique known in the art. The Refracted near-field (RNF) method or SCALP may be used to measure the stress profile and the depth of compression (DOC). When the RNF method is utilized to measure the stress profile, the maximum CT value provided by SCALP is utilized in the RNF method. In particular, the stress profile measured by RNF is force balanced and calibrated to the maximum CT value provided by a SCALP measurement. The RNF method is described in U.S. Patent No.8,854,623, entitled “Systems and methods for measuring a profile characteristic of a glass sample”, which is incorporated herein by reference in its entirety. In particular, the RNF method includes placing the glass article adjacent to a reference block, generating a polarization-switched light beam that is switched between orthogonal polarizations at a rate of from 1 Hz to 50 Hz, measuring an amount of power in the polarization- switched light beam and generating a polarization-switched reference signal, wherein the measured amounts of power in each of the orthogonal polarizations are within 50% of each other. The method further includes transmitting the polarization-switched light beam through the glass sample and reference block for different depths into the glass sample, then relaying the transmitted polarization-switched light beam to a signal photodetector using a relay optical system, with the signal photodetector generating a polarization-switched detector signal. The method also includes dividing the detectorSP23-267 signal by the reference signal to form a normalized detector signal and determining the profile characteristic of the glass sample from the normalized detector signal. Ion Exchange (IOX) Treatment

[0051] Chemical strengthening of glass substrates having base compositions is done by placing the ion-exchangeable glass substrates in a molten bath containing cations (e.g., K+, Na+, Ag+, etc) that diffuse into the glass while the smaller alkali ions (e.g., Na+, Li+) of the glass diffuse out into the molten bath. The replacement of the smaller cations by larger ones creates compressive stresses near the top surface of glass. Tensile stresses are generated in the interior of the glass to balance the near- surface compressive stresses.

[0052] There are processing challenges to make strengthened glasses with high CS and deep DOL or DOC. Typically, in ion exchange manufacturing, there are two types of strengthening processes: single ion exchange (SIOX) and double ion exchange (DIOX).

[0053] SIOX is one-step process which is simple and typically a cost-effective way to conduct ion exchange. CS and DOL of SIOX are determined primarily by bath composition, IOX temperature and time, and they are inversely correlated to each other. This means that to achieve a higher CS, the IOX time cannot be long and, thus, the DOL cannot be increased so deeply.

[0054] DIOX is two-step process where a first step (Step 1 or IOX-1) is designed to build a deep DOC and a second step (Step 2 or IOX-2) is designed to have a high CS with a shorter DOL. DIOX is an advantageous process to build with high CS and deep DOC to withstand damage introduction failure. However, DIOX can still lack capacity to build a stress profile with both high CS and DOL.

[0055] Herein, a three-step ion exchange (TIOX) is introduced. To create a stress profile with high CS, and deep DOL and / or DOC and / or increased compressive stress integral over depths, IOX processes herein include three ion exchange steps. A third step (Step 3 or IOX-3) in conjunction with a traditional Step 2 (IOX-2) and Step 1 (IOX- 1) is advantageous in achieving a higher CS and deeper DOL than a SIOX or a DIOX, utilizing standard ion exchange conditions of the industry.SP23-267

[0056] The three steps of the TIOX are referred to as Step 1, Step 2, and Step 3.

[0057] Step 1 includes: exposing a glass substrate that contains an alkali metal oxide in a base composition to a first ion exchange (IOX-1) treatment including a first bath comprising a large cation, e.g., sourced by one or more molten potassium salts, for a first duration at a first temperature that is less than a strain point of the glass substrate. An optional scavenging additive may be added to the bath, typically in an amount of 0.5% by weight. In one or more implementations, the potassium salt(s) and optional scavenging additive total 100% by weight in the first bath. In one or more implementations, Step 1 is carried out in 100 weight % KNO3 bath or a combination of KNO3 and K2CO3 at a relatively higher temperature and long IOX time to build a deep DOL but still have a relatively high CS, for example, as high as a SIOX process could possibly achieve. In one or more implementations, the IOX-1 temperature and time is designed to build up a deep DOL greater than 20 micrometers.

[0058] Step 2 includes: following the IOX-1, exposing the glass substrate to a second ion exchange (IOX-2) treatment including a second bath comprising an admixture of ion-exchangeable molten salts and optional scavenging additive for a second duration that is less than the first duration at a second temperature that is greater than or equal to the first temperature and less than the strain point. In one or more implementations, Step 2 is carried out in KNO3-NaNO3 mixed bath (preferably a high NaNO3 bath) at a temperature equal to or higher than Step 1. In one or more implementations, the second bath comprises a Na and K cation mixture molten salt, preferably with Na / K weight ratio greater than 1. An optional scavenging additive may be added to the bath, typically in an amount of 0.5% by weight. In one or more implementations, the admixture of Na and K cation molten salts and optional scavenging additive total 100% by weight in the second bath. A purpose is to exchange out K ions near the surface with Na ions to reset a high Na concentration at the glass surface that was depleted by Step1. Step 2 should be carried out at a temperature equal to or higher than Step 1 for a short of IOX time to make sure the depth of Na ↔ K ion exchange is less than that of Step 1, preferably less than half of Step 1. After Step 2, the surface CS is decreased significantly with a peak CS buried into the bulk glass. While Step 2 seems opposite to a goal of CS enhancement, it is this step that provides some fresh Na ions near the surface for the further strengthening at Step 3. The IOX-2 processSP23-267 parameters (bath composition, IOX temperature and time) are designed to ensure CS at the surface does not drop to the negative (change from compressive stress to tensile stress).

[0059] Step 3 includes: following the IOX-2, exposing the glass substrate to a third ion exchange (IOX-3) treatment including a third bath comprising one or more molten potassium salts for a third duration that is less than the first duration at a third temperature that is less than the first temperature. An optional scavenging additive may be added to the bath, typically in an amount of 0.5% by weight. In one or more implementations, the potassium salt(s) and optional scavenging additive total 100% by weight in the third bath. In one or more implementations, Step 3 is carried out in 100% KNO3 bath, or preferably in a KNO3-K2CO3 mixed bath for IOX enhancement, at a lower temperature (lower than Step 1). A purpose of Step 3 is to reintroduce K ions into the glass via K ↔ Na ion exchange to restore K concentration at the surface to the maximum. Since Step 3 is carried out at lower temperature and for a shorter time, the amount of K exchanged into the glass in this step will give a much greater boost to CS than the CS drop caused by K depletion near the surface via Na ↔ K ion exchange from Step 2, which is conducted at much higher temperature (meaning less CS drop). As a result, one can achieve higher CS and deeper DOL, DOC, and / or compressive stress integral than that of Step1.

[0060] This TIOX approach is unique, and different from existing SIOX and DIOX by offering a process that can achieve a higher CS and deeper DOL than the conventional SIOX and DIOX, while at the same time allowing stress to be placed at desired depths for increased damage resistance. TIOX offers wide processing windows for strengthening glasses with improved stress profiles.

[0061] In some implementations, the methods herein involve ion exchange that can be achieved by thermal-diffusion, electro-diffusion processes involving molten salt admixtures of Li+, Na+, K+, Rb+, Cs+, Ag+, Tl+. General Overview of Properties of Glass Articles

[0062] Chemical strengthening glasses with high CS and deep DOL or DOC are desired in the consumer electronic devices / display, for example headsets, where a high velocity impact, e.g., stresses significantly exceeding 1 Gpa, is usually involved.SP23-267 To withstand a high velocity impact, a strengthening glass desirably have a very high CS to overcome over-stress failure and a deep DOL or DOC to overcome damage- introduction failure.

[0063] Glass articles herein have stress profiles that are designed to have improved protection of glass devices from strong impacts. Such devices include 3D devices having preferably thicknesses of greater than or equal to 0.70 millimeters to less than or equal to 1.3 millimeters. High compressive stress at the surface (Csmax) in combination with compressive stress integral to desired depths improve survival of high stress-impact events.

[0064] Alkali aluminosilicate glasses have good ion exchangeability, and chemical strengthening processes have been used to achieve high strength and high toughness properties in alkali aluminosilicate glasses. Sodium aluminosilicate glasses are highly ion exchangeable glasses with high glass formability and quality. Lithium aluminosilicate glasses are highly ion exchangeable glasses with high glass quality. The substitution of Al2O3 into the silicate glass network increases the interdiffusivity of monovalent cations during ion exchange. By chemical strengthening in a molten salt bath (e.g., KNO3 or NaNO3), glasses with high strength, high toughness, and high indentation cracking resistance can be achieved. The stress profiles achieved through chemical strengthening may have a variety of shapes that increase the drop performance.

[0065] Therefore, lithium aluminosilicate glasses with good physical properties, chemical durability, and ion exchangeability have drawn attention for use as cover glass. Through different ion exchange processes, greater central tension (CT), depth of compression (DOC), and high compressive stress (CS) can be achieved.

[0066] In implementations of glass compositions described herein, the concentration of constituent components (e.g., SiO2, Al2O3, Li2O, and the like) are given in mole percent (mol%) on an oxide basis, unless otherwise specified. It should be understood that any of the variously recited ranges of one component may be individually combined with any of the variously recited ranges for any other component.

[0067] In the glass articles, there is an alkali metal oxide having a non-zero concentration that varies from one or both of first and second surfaces to a depth ofSP23-267 layer (DOL) with respect to the metal oxide. A stress profile is generated due to the non-zero concentration of the metal oxide(s) that varies from the first surface. The non-zero concentration may vary along a portion of the article thickness. This change may be measured by known methods in the art including microprobe.

[0068] In some implementations, the variation in concentration may be continuous along thickness segments in the range from about 10 micrometers to about 30 micrometers. In some implementations, the concentration of the alkali metal oxide decreases from the first surface to a value between the first surface and the second surface and increases from the value to the second surface.

[0069] The concentration of alkali metal oxide may include more than one metal oxide (e.g., a combination of Na2O and K2O). In some implementations, where two metal oxides are utilized and where the radius of the ions differ from one or another, the concentration of ions having a larger radius is greater than the concentration of ions having a smaller radius at shallow depths, while at deeper depths, the concentration of ions having a smaller radius is greater than the concentration of ions having larger radius.

[0070] The concentration of the alkali metal oxide may be determined from a baseline amount of the metal oxide in the glass substrate ion exchanged to form the glass article, for example, the concentration may be determined relative to the base composition.

[0071] In one or more implementations, the glass article comprises: t in the range of 0.3 mm to 1.5 mm, and all values and subranges therebetween; and / or t may be less than or equal to 1.2 mm, less than or equal 1.1 mm, less than or equal 1.0 mm, less than or equal to 0.9, less than or equal to 0.80 mm, less than or equal to 0.70 mm, less than or equal to 0.65 mm, less than or equal to 0.50 mm and / or greater than or equal to 0.5 mm, greater than or equal to 0.6 mm, greater than or equal to 0.7 mm, greater than or equal to 0.8 mm, including all values and subranges therebetween. In one or more implementations, the thickness t is in a range of 0.70 millimeters to 1.3 millimeters.

[0072] In one or more implementations, the glass article comprises: a maximum compressive stress (CSmax) that is greater than or equal to greater than or equal toSP23-267 950 MPa, greater than or equal to 1000 MPa, greater than or equal to 1050 MPa, greater than or equal to 1100 MPa, greater than or equal to 1150 MPa, greater than or equal to 1200 MPa, greater than or equal to 1250 MPa, greater than or equal to 1300 MPa, greater than or equal to 1350 MPa, greater than or equal to 1400 MPa, including all values and subranges therebetween.

[0073] In one or more implementations, the glass article comprises: a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter, and optionally including one or more of the following: the compressive stress integral at a depth of 8 micrometers is greater than or equal to 8.5 MPa^ millimeter; the compressive stress integral at a depth of 12 micrometers is greater than or equal to 11.7 MPa^ millimeter; the compressive stress integral at a depth of 16 micrometers is greater than or equal to 14.1 MPa^ millimeter; the compressive stress integral at a depth of 20 micrometers is greater than or equal to 15.7 MPa^ millimeter; and the compressive stress integral at a depth of 25 micrometers is greater than or equal to 16.7 MPa^ millimeter.

[0074] In one or more implementations, the glass article comprises: a tensile stress factor Kt, which is a frangibility limit having units of stress-intensity factor, e.g., MPa√m. As utilized herein, the quantity Kt is the tensile-stress factor given by equation (I):,

[0076] where σ is represented by one of the in-plane components as the in-plane components are presumed to be equal), and z is the position in the thickness direction. To obtain the values of Kt in units of MPa√m, the stress values under the integral should be in MPa, while the thickness position scale z should be in m.

[0077] In some implementations, the glass article contains ion-exchanged sodium and potassium. In some implementations, the glass article contains ion-exchanged lithium, sodium, and potassium.

[0078] In some implementations, the glass article contains ion exchanged lithium, sodium, potassium and metal ion dopants such as silver, copper, zinc, titania etc. to introduce additional functionalities such as anti-microbial, self-cleaning, and the like.SP23-267

[0079] In some implementations, the glass articles, when tested per ASTM C1499- 19 with 0.5 inch diameter load ring and 1 inch diameter support ring, comprise one or more of the following: at 5 micrometer flaw depth, a failure stress of greater than or equal to 1500 MPa, greater than or equal to 1600 MPa, greater than or equal to 1700 MPa, greater than or equal to 1800 MPa, or greater than or equal to 1900 MPa; at 9 micrometer flaw depth, a failure stress of greater than or equal to 1200 MPa, or greater than or equal to 1300 MPa, greater than or equal to 1400 MPa, greater than or equal to 1500 MPa, or greater than or equal to 1600 MPa; at 13 micrometer flaw depth, a failure stress of greater than or equal to 600 MPa, greater than or equal to 700 MPa, greater than or equal to 800 MPa, greater than or equal to 900 MPa; and at 25 micrometer flaw depth, a failure stress of greater than or equal to 400 MPa, or greater than or equal to 500 MPa. Reference to “flaw depth” (a check depth or a crack tip depth) is the position or depth at which there is a tip of a crack generated by the flaw (or the flaw itself in case no crack was generated from the flaw) prior to strength testing. FIG.18 is an example micrograph of a DIOX-B comparative example herein showing a flaw and its flaw depth that was introduced by pneumatic abrasion, later revealed after ring-on-ring (ROR) testing. The flaw depth is shown as 37.79 microns.

[0080] In some implementations, in the absence of a surface etching, the glass articles have a characteristic strength of greater than or equal to 1.5 to less than or equal to 4 GPa, including greater than or equal to 2 to less than or equal to 3 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions and / or dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring 63.2.

[0081] In some implementations, articles including the front-loaded stress profile are combined with a surface etching, which includes removal of an amount of material, including, for example, from 0.2 to 20 microns per side, preferably from 0.3 to 8 microns per side, more preferably from 0.5 to 3 microns per side, even more preferably from 1 to 2.5 microns per side, to reduce depths of pre-existing flaws, or reduce sharpness of pre-existing flaws, in order to improve the strength of residual flaws to a level that can withstand the high-stress contact events. In some desired profiles, the surface CS is designed to be less than 1100 MPa, because the profiles herein may show adequate performance when combined with some surface etching in whichSP23-267 material is etched from the glass surface to improve the strength of pre-existing flaws by eliminating them, reducing their depth, and / or changing their shape through the etching process. In such cases, a combination with higher stress area to at least one of the depths of 5, 8, 12, 16, 20, or 25 micron, provides superior fracture resistance for certain flaws, compared to prior-art profiles. These flaws include edge-finishing flaws which may be very costly to reduce to below 10-micron size when the cover- glass article has a complex 3D shape. Other flaws that may need such deeper protection include some 3D-forming flaws. Furthermore, it is common for the glass surface to develop flaws during service, including scratches that may generate median cracks that go deeper than 10 microns, sometimes as deep as 15, 20, or even 25 microns. Increasing the compressive-stress area to these depths can help increase the retained strength or failure stress of such flaws to a significantly larger extent than prior-art profiles would provide.

[0082] In some implementations, the glass articles as further combined with a surface etching have a characteristic strength of greater than or equal to 2 to less than or equal to 8 GPa, including greater than or equal to 6.5 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19 with 0.5 inch load and 1 inch support rings, and / or of greater than or equal to 5 to less than or equal to 10 GPa, including greater than or equal to 8.7 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

[0083] In some implementations, with or without surface etch, the glass articles have a normalized deflection according to deflection (in mm) x thickness (in mm) x elastic modulus (in Pa) of greater than or equal to 80 (10^9 N or GN), including greater than or equal to 100 (10^9 N or GN), greater than or equal to 120 (10^9 N or GN), greater than or equal to 140 (10^9 N or GN), or greater than or equal to 150 (10^9 N or GN).

[0084] Aspect (a) is a glass article comprising: opposing first and second surfaces defining a body of the article having a thickness (t); a stress profile of the body comprising: a spike region extending from the first surface to a knee located at a depth of layer (DOL); a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa; a tail region extending from the knee to a center of theSP23-267 glass article having a central tension (CT) and including a depth of compression (DOC); and a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter.

[0085] Aspect (b) is the glass article of aspect (a), wherein the t is in a range of 0.30 millimeters to 1.5 millimeters.

[0086] Aspect (c) is the glass article of aspect (a) or (b), wherein the DOC is greater than or equal to 0.035^t.

[0087] Aspect (d) is the glass article of any one of aspects (a) to (c), including one or more of the following: the compressive stress integral at a depth of 8 micrometers is greater than or equal to 8.5 MPa^ millimeter; the compressive stress integral at a depth of 12 micrometers is greater than or equal to 11.7 MPa^ millimeter; the compressive stress integral at a depth of 16 micrometers is greater than or equal to 14.1 MPa^ millimeter; the compressive stress integral at a depth of 20 micrometers is greater than or equal to 15.7 MPa^ millimeter; and the compressive stress integral at a depth of 25 micrometers is greater than or equal to 16.7 MPa^ millimeter.

[0088] Aspect (e) is a glass article comprising: opposing first and second surfaces defining a body of the article having a thickness (t) of greater than or equal to 0.70 millimeters to less than or equal to 1.3 millimeters; a stress profile of the body comprising: a spike region extending from the first surface to a knee located at a depth of layer (DOL) of greater than or equal to 20 micrometers; a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa; and a tail region extending from the knee to a center of the glass article having a central tension (CT) and including a depth of compression (DOC), the DOC being greater than or equal to 25 micrometers.

[0089] Aspect (f) is the glass article of aspect (e) comprising a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter, and optionally including one or more of the following: the compressive stress integral at a depth of 8 micrometers is greater than or equal to 8.5 MPa^ millimeter; the compressive stress integral at a depth of 12 micrometers is greater than or equal to 11.7 MPa^ millimeter; the compressive stress integral at a depth of 16 micrometers is greater than or equal to 14.1 MPa^ millimeter; the compressive stress integral at aSP23-267 depth of 20 micrometers is greater than or equal to 15.7 MPa^ millimeter; and the compressive stress integral at a depth of 25 micrometers is greater than or equal to 16.7 MPa^ millimeter.

[0090] Aspect (g) is the glass article of any one of aspects (a) to (f) comprising a 3D configuration.

[0091] Aspect (h) is the glass article of any one of aspects (a) to (g), wherein the peak compressive stress (CSmax) of the spike region is greater than or equal to 1100 MPa, 1200 MPa, 1300 MPa, 1400 MPa, or 1500 MPa.

[0092] Aspect (i) is the glass article of one of aspects (a) to (h) comprising a lithium aluminosilicate central composition.

[0093] Aspect (j) is the glass article of aspect (i), wherein the lithium aluminosilicate central composition comprises a Na2O / Li2O molar ratio in a range of greater than or equal to 1.5 to less than or equal to 2.1.

[0094] Aspect (k) is the glass article of aspect (i) or (j), wherein the lithium aluminosilicate central composition comprises: about 50 mol% to about 69 mol% SiO2; about 12.5 mol% to about 25 mol% Al2O3; about 0 mol% to about 8 mol% B2O3; about 0.01 mol% to about 2 mol% K2O; about 11.0 mol% to about 15.0 mol% Na2O; and about 0.5 mol% to about 10 mol% Li2O.

[0095] Aspect (l) is a consumer electronic product, comprising: a housing having a front surface, a back surface, and side surfaces; electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and the glass article of any one of aspects (a) to (k) disposed over the display.

[0096] Aspect (m) is a method of making a glass article, the glass article having opposing first and second surfaces defining a body having a thickness (t), the method comprising: exposing a glass substrate that contains an alkali metal oxide in a base composition to a first ion exchange (IOX-1) treatment including a first bath comprising one or more molten potassium salts for a first duration at a first temperature that isSP23-267 less than a strain point of the glass substrate; following the IOX-1, exposing the glass substrate to a second ion exchange (IOX-2) treatment including a second bath comprising an admixture of ion-exchangeable molten salts and optional scavenging additive for a second duration that is less than the first duration at a second temperature that is greater than or equal to the first temperature and less than the strain point; and following the IOX-2, exposing the glass substrate to a third ion exchange (IOX-3) treatment including a third bath comprising one or more molten potassium salts for a third duration that is less than the first duration at a third temperature that is less than the first temperature.

[0097] Aspect (n) is the method of aspect (m) wherein: the first bath comprises greater than or equal to 90% by weight of potassium nitrate (KNO3) and less than or equal to 10% by weight of sodium nitrate (NaNO3); the admixture of the ion- exchangeable molten salts of the second bath comprises potassium nitrate (KNO3) and sodium nitrate (NaNO3) and a sodium-to-potassium (Na:K) ratio of greater than 1; and the third bath comprises by weight: 0 to less than or equal to 15% potassium carbonate (K2CO3) and potassium nitrate (KNO3) to total 100 wt. %.

[0098] Aspect (o) is the method of aspect (m) or (n), wherein: the first duration is greater than or equal to 5 hours and less than or equal to 50 hours; the second duration is greater than or equal to 0.5 hours and less than or equal to 2 hours; and the third duration is greater than or equal to 1 hours and less than 15 hours.

[0099] Aspect (p) is the method of any one of aspects (m) to (o), wherein: the first temperature is greater than or equal to 400°C and less than or equal to 500°C; the second temperature is greater than or equal to 400°C and less than or equal to 550°C; and the third temperature is greater than or equal to 350°C and less than 450°C.

[0100] Aspect (q) is the method of any one of aspects (m) to (p), wherein the second bath comprises by weight: greater than or equal to 5 % to less than or equal to 45 % potassium nitrate (KNO3) and greater than or equal to 55 % to less than or equal to 95 % sodium nitrate (NaNO3) to total 100 wt. %.

[0101] Aspect (r) is the method of any one of aspects (m) to (q), which excludes any thermal relaxation step that is in the absence of a molten salt bath between the IOX-1 and the IOX-3.SP23-267

[0102] Aspect (s) is the method of any one of aspects (m) to (r), wherein the glass substrate comprises: a soda lime silicate composition; an alkali-alumino silicate composition; an alkali-containing borosilicate composition; an alkali-containing aluminoborosilicate composition, or an alkali-containing phosphate composition.

[0103] Aspect (t) is the method of any one of aspects (m) to (s), wherein the glass substrate comprises a central composition comprising: a Na2O / Li2O molar ratio in a range of greater than or equal to 1.5 to less than or equal to 2.1 and / or about 50 mol% to about 69 mol% SiO2; about 12.5 mol% to about 25 mol% Al2O3; about 0 mol% to about 8 mol% B2O3; about 0.01 mol% to about 2 mol% K2O; about 11.0 mol% to about 15.0 mol% Na2O; and about 0.5 mol% to about 10 mol% Li2O.

[0104] Aspect (u) is any one of aspects (a) to (t) wherein the glass article comprises a characteristic strength of greater than or equal to 1.5 GPa to less than or equal to 8 GPa, including 1.5 to 4 GPa and 4 to 8 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring, and / or of greater than or equal to 1.5 GPa to less than or equal to 10 GPa, including 1.5 to 4 GPa and 5 to 10 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

[0105] Aspect (v) is any one of aspects (a) to (u) in an absence of surface etching wherein the glass article comprises a characteristic strength of greater than or equal to 1.5 GPa to less than or equal to 4 GPa at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions and / or under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

[0106] Aspect (w) is any one of aspects (a) to (u) wherein after ion exchange, the glass article further comprises a surface etching.

[0107] Aspect (x) is aspect (w) wherein the glass article comprises a characteristic strength of greater than or equal to 4 GPa to less than or equal to 8 GPa, including greater than or equal to 6.5 GPa at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19, and / or ofSP23-267 greater than or equal to 5 GPa to less than or equal to 10 GPa, including greater than or equal to 8.7 GPa at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

[0108] Aspect (y) is any one of aspects (a) to (x) wherein the glass article comprises a normalized deflection according to deflection (in mm) x thickness (in mm) x elastic modulus (in Pa) of greater than or equal to 80 (10^9 N or GN), or greater than 100 (10^9 N or GN), or greater than or equal to 120 (10^9 N or GN), greater than or equal to 140 (10^9 N or GN), or greater than or equal to 150 (10^9 N or GN). Glass Substrates

[0109] Examples of glasses that may be used as substrates may include soda-lime silicate glass compositions or alkali-alumino silicate glass compositions or alkali- containing aluminoborosilicate glass compositions, though other glass compositions are contemplated such as soda-lime silicate glass. Specific examples of glass substrates that may be used include but are not limited to a soda-lime silicate glass, an alkali-alumino silicate glass, an alkali-containing borosilicate glass, an alkali- containing aluminoborosilicate glass, or an alkali-containing phosphate glass. In an implementation, the glass substrate comprises an alkali-containing lithium alumino silicate composition. The glass substrates have base compositions that may be characterized as ion exchangeable. As used herein, “ion exchangeable” means that a substrate comprising the composition is capable of exchanging cations located at or near the surface of the substrate with cations of the same valence that are either larger or smaller in size. In some implementations, the glass substrate comprises an alkali content of greater than 2 mol %

[0110] In one or more implementations, glass substrates may include a lithium- containing aluminosilicate. In an implementation, a glass substrate comprises a Na2O / Li2O molar ratio in a range of greater than or equal to 1.5 to less than or equal to 2.1, including all values and ranges therebetween, including: greater than or equal to 1.8 to less than or equal to 2.0.

[0111] In an implementation, a glass substrate comprises a central composition including: about 50 mol% to about 69 mol% SiO2; about 12.5 mol% to about 25 mol%SP23-267 Al2O3; about 11.0 mol% to about 15.0 mol% Na2O; about 0.5 mol% to about 10 mol% Li2O; about 0.01 mol% to about 2 mol% K2O. In some implementations, the glass substrate further comprises one or more of the following ingredients: about 0 mol% to about 8 mol% B2O3; about 0.5 mol% to about 2 mol % CaO; about 0.5 mol% to about 2 mol % MgO; about 0.1 mol% to about 1 mol % ZnO; about 0.1 mol% to about 0.5 mol % SnO2; about 0 mol% to about 0.1 mol % TiO2; about 0 mol% to about 0.1 mol % Fe2O3; about 0 mol% to about 0.1 mol % P2O5; about 0 mol% to about 0.1 mol % ZrO2; and about 0 mol% to about 0.1 mol % MnO2.

[0112] In implementations, the glass substrates may be formed from any composition capable of forming the stress profiles. In some implementations, the glass substrates may be formed from the glass compositions described in U.S. Application No.16 / 202,691 titled “Glasses with Low Excess Modifier Content,” filed November 28, 2018, the entirety of which is incorporated herein by reference. In some implementations, the glass articles may be formed from the glass compositions described in U.S. Application No. 16 / 202,767 titled “Ion-Exchangeable Mixed Alkali Aluminosilicate Glasses,” filed November 28, 2018, the entirety of which is incorporated herein by reference.

[0113] The glass substrates may be characterized by the manner in which it may be formed. For implementation, the glass substrates may be characterized as float- formable (i.e., formed by a float process), down-drawable and, in particular, fusion- formable or slot-drawable (i.e., formed by a down draw process such as a fusion draw process or a slot draw process). In implementations, the glass substrates may be roll formed.

[0114] Some implementations of the glass substrates described herein may be formed by a down-draw process. Overflow down-draw processes produce glass substrates having a uniform thickness that possess relatively pristine surfaces. Because the average flexural strength of the glass article is controlled by the amount and size of surface flaws, a pristine surface that has had minimal contact has a higher initial strength. In addition, overflow down-draw glass articles have a very flat, smooth surface that can be used in its final application without costly grinding and polishing.SP23-267

[0115] Some implementations of the glass substrates may be described as fusion- formable (i.e., formable using a fusion draw process). The fusion process is an overflow down-draw process that uses a drawing tank that has a channel for accepting molten glass raw material. The channel has weirs that are open at the top along the length of the channel on both sides of the channel. When the channel fills with molten material, the molten glass overflows the weirs. Due to gravity, the molten glass flows down the outside surfaces of the drawing tank as two flowing glass films. These outside surfaces of the drawing tank extend down and inwardly so that they join at an edge below the drawing tank. The two flowing glass films join at this edge to fuse and form a single flowing glass article. The fusion draw method offers the advantage that, because the two glass films flowing over the channel fuse together, neither of the outside surfaces of the resulting glass article comes in contact with any part of the apparatus. Thus, the surface properties of the fusion drawn glass article are not affected by such contact.

[0116] Some implementations of the glass substrates described herein may be formed by a slot draw process. The slot draw process is distinct from the fusion draw method. In slot draw processes, the molten raw material glass is provided to a drawing tank. The bottom of the drawing tank has an open slot with a nozzle that extends the length of the slot. The molten glass flows through the slot / nozzle and is drawn downward as a continuous glass article and into an annealing region.

[0117] In one or more implementations, the glass substrates described herein may exhibit an amorphous microstructure and may be substantially free of crystals or crystallites. In other words, the glass substrates and glass articles exclude glass- ceramic materials in some implementations. End Products

[0118] The glass articles disclosed herein may be incorporated into another article such as an article with a display (or display articles) (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, and the like); architectural articles; transportation articles (e.g., automobiles, trains, aircraft, sea craft, etc.); appliance articles; defense articles; medical, packaging and safety articles; or any article that may benefit from some transparency, scratch-resistance, abrasionSP23-267 resistance or a combination thereof. An exemplary article incorporating any of the glass articles disclosed herein is shown in FIGS.2A and 2B. Specifically, FIGS.2A and 2B show a consumer electronic device 200 including a housing 202 having front 204, back 206, and side surfaces 208; electrical components (not shown) that are at least partially inside or entirely within the housing and including at least a controller, a memory, and a display 210 at or adjacent to the front surface of the housing; and a cover 212 at or over the front surface of the housing such that it is over the display. In some implementations, the cover 212 and / or housing 202 may include any of the glass articles disclosed herein. EXAMPLES

[0119] Various implementations will be further clarified by the following examples. Experiments were designed with various DOL targets. In these examples “DOL” is referring to the DOL as-reported by FSM. Examples 1 and 2-I targeted a DOL within ~30 to ~ 35 micrometer range. Examples 4 and 5 targeted a DOL within ~65 to ~ 70 micrometer range. Example 6 targeted a DOL within ~85 to ~90 micrometer range.

[0120] Glass substrates of Composition I and thickness 0.8 millimeters were ion exchanged under various conditions in a series including three ion exchange (TIOX) baths, summarized in Table 1. Glass substrates of Composition I and thickness 0.8 millimeters were also ion exchanged under comparative conditions: utilizing a single ion exchange (SIOX) bath, or double ion exchange (DIOX) baths, summarized in Table 1. A goal of the TIOX conditions included preparing glass articles having higher front- loaded compressive stress CS compared to the comparative articles in order to improve probability of surviving high-stress impact events. The substrates all utilized 2D configurations without any 3D thermal history. Table 1SP23-267

[0121] Composition I had the following ingredients: 0.03 mol % K2O; 11.73 mol % Na2O; 5.83 mol % Li2O; 18.52 mol % Al2O3; 59.16 mol % SiO2; 1.71 mol % CaO; 1.87 mol % MgO; 0.91 mol % ZnO; 0.11 mol % SnO2; 0.06 mol % TiO2; 0.02 mol % Fe2O3; 0.02 mol % B2O3; 0.01 mol % P2O5; 0.01 mol % ZrO2; 0.01 mol % MnO2 (0.00 mol % SrO); and a Na2O / Li2O molar ratio of 2.

[0122] The resulting articles were analyzed for various stress profile parameters summarized in Table 2. The CSmax and DOL and CT values of Table 2 were measured by FSM at 598 nm, and an SOC value at 546 nm, which would generally yield ~0.8% under-reporting of Csmax as compared to an SOC value at 598 nm, which is the appropriate value to match with the FSM measurement wavelength. Accordingly, with reference to Table 2, actual values of Csmax, CT, and Kt would be expected to be ~0.8% higher than reported. DOL / t was calculated. Kt is a tensile stress factor discussed herein, derived from the FSM profile.SP23-267 Table 2

[0123] FIG.5 is a graph of concentration (mole %) versus depth (micrometers) for K2O, Na2O, and Li2O for Example 2-I. As shown in Table 1, the TIOX conditions were: Step1 (S1): 100wt%KNO3 at 410°C / 25hrs; Step2 (S2): 30wt%KNO3 / 70wt%NaNO3at 430°C / 1hr; and Step 3 (S3): 95 wt%KNO3 / 5 wt%K2CO3 at 385°C / 8hrs. The majority of ion exchange was K ↔ Na ion exchange occurring within depth of ~30µm. Step 1 of K ↔ Na ion exchange yielded a K2O concentration profiles to the depth of ~28µm with a surface concentration of ~13 mole %. After Step 2, the surface concentration of K2O decreased from ~13 mole % to ~3.5 mole % while the surface concentration of Na2O increased from ~2 mole% to ~14 mole% via Na ↔ K ion exchange. The depth of Na ↔ K ion exchange in this step is about ~15 µm. There is also some ↔ Na Li ion exchange in this step that largely impacts the Li cation profile within the depth of ~30 µm. After Step 3, the surface concentration increased to ~15 mole %, a level even higher than that (~13 mole %) after Step 1. The depth of K2O profile after Step 3 wasSP23-267 about ~31 µm which is deeper than that after Step1, suggesting a higher CS and a deeper DOL, which were confirmed by FSM and modeling data.

[0124] Modeling analysis conducted by diffusion modeling of stress (Mpa) versus normalized position (z / thickness) of various Examples of Table 1 are shown in a graph of FIG.6. Various parameters generated by the modelling are summarized in Table 3. Modeling analysis estimates are generally more accurate for concentration distributions than surface stresses, for example CSmax. The simulated stress profiles for Examples 1 and 2-I illustrate that TIOX is capable of yielding a much higher CS than SIOX with a similar DOL and a much deeper DOL than DIOX with a higher CS. Table 3 ModelingSP23-267

[0125] FIG. 7 provides a graph of compressive stress (Mpa) versus thickness (micrometers) for Example 1. FIG. 8 provides a A(z) graph of compressive stress integral (Mpa^millimeter) versus thickness (micrometers) for Example 1 based on data of FIG.7.

[0126] FIG. 9 provides a graph of compressive stress (Mpa) versus thickness (micrometers) for Example 2-II. FIG.10 provides a A(z) graph of compressive stress integral (Mpa^millimeter) versus thickness (micrometers) for Example 2-II based on data of FIG.9.

[0127] FIG. 11 provides a graph of compressive stress (Mpa) versus thickness (micrometers) for Example 3. FIG.12 provides a A(z) graph of compressive stress integral (Mpa^millimeter) versus thickness (micrometers) for Example 3 based on data of FIG.11.

[0128] The stress profiles of FIGS.7 and 9 and 11 are near-surface profiles obtained by an inverse-IWKB method, according to a stepwise linear IWKB method according to U.S. Patent No.9,140,543, which is incorporated herein by reference in its entirety. The deep end of the IWKB profiles present reduced signal-to-noise ratio, which does not significantly affect the accuracy of the DOC, or the values of A(z), particularly for z ≤ DOC. There is, however, a potential for surface CS variation on the order of 10- 20 Mpa associated with the finite resolution of the IWKB-based stress-profile extraction.

[0129] Table 4.A provides CSmax and DOC for Examples 2-II and 3 reported according to the IWKB-based surface profiles. CT (Mpa) and Kt are calculated based on IWKB-based surface profiles and methods according to U.S. Patent No. 11,639,310, which is incorporated herein by reference in its entirety. DOC / t was calculated. DOL values were obtained from FSM measured at 598 nm. DOL / t was calculated. Table 4.B provides compressive stress integral at various depths for Examples 1, 2-II, and 3 where z= 5 µm, 8 µm, 12 µm, 16 µm, 20 µm, and 25 µm, which are included in the A(z) graphs of FIGS.8, 10, and 12 (Mpa*mm vs thickness (µm)).SP23-267 Table 4.ATable 4.B

[0130] Example 1 and Comparative Example B were analyzed for an abraded R-o- R comparison (0.5 inch diameter load ring and 1 inch diameter support ring).

[0131] For abrasion, pneumatic abrasion was used to impart damage to the glass specimens. A masking tape with 1 / 8 inch diameter hole at the center was used to cover the specimen before abrasion. Thus, abraded region was restricted to 1 / 8 inch circular spot at the center of the sample. 90 grit SiC was used as the abrasive material. Various pressures ranging from 1 psi to 15 psi were used to create the flaws of varied depths. Abraded samples are tested after 12hrs in 23°C 50%RH conditions using RoR.

[0132] For retained strength / failure stress determination and flaw depth measurement, failure stress was evaluated from the measured failure load using ASTM C1499-19 and details as provided for the following Example 7. The broken sample was preserved and fractography is performed. The origin of the failure was isolated and flaw depth (check depth or crack tip depth) was measured. The failure stress (MPa) vs flaw depth (micrometers) is shown in FIG.13.SP23-267

[0133] Example 1 had significantly higher failure stress (almost 2X at 9 µm flaw depth) at deeper flaw depths (2 µm to 25 µm) as compared to Comparative Example B. Use-case flaw depths seen for such applications and for similar MCE (mobile consumer electronics) applications are in this range.

[0134] FIG. 14 is a graph of failure probability (%) versus failure stress (MPa) for Example 1. Characteristic strength (63.2% failure probability in 2 parameter Weibull distribution) of Example 1 was 2.4 GPa under quasi-static conditions, and 2.6 GPa under dynamic conditions using ASTM C1499-19 and details as provided for the following Example 7.

[0135] Example 7. A glass substrate of Composition I and thickness 0.8 millimeters that was ion exchanged under conditions as according to Example 1 was thereafter subjected to a surface etching.

[0136] Example 7 was tested for equi-biaxial flexure or ring-on-ring as per ASTM C1499-19 (equi-biaxial Flexure (RoR) with 0.5 inch diameter and 1 inch diameter load and support rings, respectively) conducted with an apparatus including a support ring and a load ring to which a load is applied, a specimen residing between the support ring and the load ring. For quasi-static, strain rate, ἑ = 0.003 / s, and displacement rate, = 1.2 mm / min. For dynamic static, strain rate, ἑ = 38.5 / s, and displacement rate, = 1300 mm / s.

[0137] Equi-biaxial Strength or Failure Stress:

[0138] F is breaking load in units of N; DLis load ring diameter; ν is Poisson’s ratio; Dsis support ring diameter in units of mm; E is the modulus of elasticity in units of MPa, h is test specimen thickness; l1 and l2 are lengths of the edges.SP23-267

[0139] FIG. 15 is a graph of failure probability (%) versus failure stress (MPa) for Example 7. Characteristic strength (63.2% failure probability in 2 parameter Weibull distribution) of Example 7 was 6.5 GPa under quasi-static conditions, and 8.7GPa under dynamic conditions.

[0140] FIG.16 is a load-deflection plot for Example 7. Deflection is:

[0141] Example 7 showed significant deflection (almost 3 times its thickness) during RoR testing.

[0142] FIG. 17 is a normalized load-deflection plot for Example 7 with respect to deflection*thickness*elastic modulus. Load vs Deflection*thickness*Elastic modulus is greater than 140. Such materials can withstand significant bending during use-case events such as drop and the like.

[0143] Examples 1 and 7 represent one aspect herein, comprising: a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa, including greater than or equal to 1100 MPa, greater than or equal to 1200 MPa, greater than or equal to 1300 MPa, greater than or equal to 1400 MPa, or greater than or equal to 1500 MPa; and / or a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter; and / or t in a range of 0.30 millimeters to 1.5 millimeters; and / or DOC is greater than or equal to 0.035^t; and / or a characteristic strength of greater than or equal to 1.5 GPa to less than or equal to 8 GPa at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring, and / or of greater than or equal to 1.5 GPa to less than or equal to 10 GPa at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring; and / or a normalized deflection according to deflection (in mm) x thickness (in mm) x elastic modulus (in Pa) of greater than or equal to 80 (10^9 N or GN), greater than or equal to 100 (10^9 N or GN), or greater than or equal to 120SP23-267 (10^9 N or GN), greater than or equal to 140 (10^9 N or GN), or greater than or equal to 150 (10^9 N or GN).

[0144] All compositional components, relationships, and ratios described in this specification are provided in mol% unless otherwise stated. All ranges disclosed in this specification include any and all ranges and subranges encompassed by the broadly disclosed ranges whether or not explicitly stated before or after a range is disclosed.

[0145] It will be apparent to those skilled in the art that various modifications and variations can be made to the implementations described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various implementations described herein provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

SP23-267 What is claimed is:

1. A glass article comprising: opposing first and second surfaces defining a body of the article having a thickness (t); a stress profile of the body comprising: a spike region extending from the first surface to a knee located at a depth of layer (DOL); a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa; a tail region extending from the knee to a center of the glass article having a central tension (CT) and including a depth of compression (DOC); and a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter.

2. The glass article of claim 1, wherein the t is in a range of 0.30 millimeters to 1.5 millimeters, and / or the DOC is greater than or equal to 0.035^t.

3. The glass article of claim 1 or claim 2, including one or more of the following: the compressive stress integral at a depth of 8 micrometers is greater than or equal to 8.5 MPa^ millimeter; the compressive stress integral at a depth of 12 micrometers is greater than or equal to 11.7 MPa^ millimeter; the compressive stress integral at a depth of 16 micrometers is greater than or equal to 14.1 MPa^ millimeter; the compressive stress integral at a depth of 20 micrometers is greater than or equal to 15.7 MPa^ millimeter; and the compressive stress integral at a depth of 25 micrometers is greater than or equal to 16.7 MPa^ millimeter.

4. A glass article comprising: opposing first and second surfaces defining a body of the article having a thickness (t) of greater than or equal to 0.70 millimeters to less than or equal to 1.3 millimeters; a stress profile of the body comprising:SP23-267 a spike region extending from the first surface to a knee located at a depth of layer (DOL) of greater than or equal to 20 micrometers; a peak compressive stress (CSmax) of the spike region being greater than or equal to 1000 MPa; and a tail region extending from the knee to a center of the glass article having a central tension (CT) and including a depth of compression (DOC), the DOC being greater than or equal to 25 micrometers.

5. The glass article of claim 4 comprising a compressive stress integral at a depth of 5 micrometers that is greater than or equal to 5.2 MPa^millimeter, and optionally including one or more of the following: the compressive stress integral at a depth of 8 micrometers is greater than or equal to 8.5 MPa^ millimeter; the compressive stress integral at a depth of 12 micrometers is greater than or equal to 11.7 MPa^ millimeter; the compressive stress integral at a depth of 16 micrometers is greater than or equal to 14.1 MPa^ millimeter; the compressive stress integral at a depth of 20 micrometers is greater than or equal to 15.7 MPa^ millimeter; and the compressive stress integral at a depth of 25 micrometers is greater than or equal to 16.7 MPa^ millimeter.

6. The glass article of any one of claims 1-5 comprising a 3D configuration.

7. The glass article of any one of claims 1-6, wherein the peak compressive stress (CSmax) of the spike region is greater than or equal to 1100 MPa, 1200 MPa, 1300 MPa, 1400 MPa, or 1500 MPa.

8. The glass article of any one of claims 1-7 comprising a lithium aluminosilicate central composition, and optionally, wherein the lithium aluminosilicate central composition comprises a Na2O / Li2O molar ratio in a range of greater than or equal to 1.5 to less than or equal to 2.

1.

9. The glass article of claim 8, wherein the lithium aluminosilicate central composition comprises: about 50 mol% to about 69 mol% SiO2;SP23-267 about 12.5 mol% to about 25 mol% Al2O3; about 0 mol% to about 8 mol% B2O3; about 0.01 mol% to about 2 mol% K2O; about 11.0 mol% to about 15.0 mol% Na2O; and about 0.5 mol% to about 10 mol% Li2O.

10. The glass article of any one of claims 1-9 comprising: when tested per ASTM C1499-19 with 0.5 inch diameter loading ring and 1 inch diameter support ring, one or more of the following: at 5 micrometer flaw depth, a failure stress of greater than or equal to 1500 MPa, greater than or equal to 1600 MPa, greater than or equal to 1700 MPa, greater than or equal to 1800 MPa, or greater than or equal to 1900 MPa; at 9 micrometer flaw depth, a failure stress of greater than or equal to 1200 MPa, or greater than or equal to 1300 MPa, greater than or equal to 1400 MPa, greater than or equal to 1500 MPa, or greater than or equal to 1600 MPa; at 13 micrometer flaw depth, a failure stress of greater than or equal to 600 MPa, greater than or equal to 700 MPa, greater than or equal to 800 MPa, greater than or equal to 900 MPa; and at 25 micrometer flaw depth, a failure stress of greater than or equal to 400 MPa, or greater than or equal to 500 MPa.

11. The glass article of any one of claims 1-10 comprising: a characteristic strength of greater than or equal to 1.5 to less than or equal to 8 GPa at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring, and / or of greater than or equal to 1.5 to less than or equal to 10 GPa at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

12. The glass article of claim 11 in an absence of a surface etching comprising: a characteristic strength of greater than or equal to 1.5 to less than or equal to 4 GPaSP23-267 under quasi-static and / or under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

13. The glass article of claim 11 further combined with a surface etching, comprising: a characteristic strength of greater than or equal to 4 GPa to less than or equal to 8, including greater than or equal to 6.5 GPa, at 63.2% failure probability in 2 parameter Weibull distribution under quasi-static conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring, and / or of greater than or equal to 5 GPa to less than or equal to 10, including greater than or equal to 8.7 GPa at 63.2% failure probability in 2 parameter Weibull distribution under dynamic conditions according to ASTM C1499-19 with 0.5 inch diameter load ring and 1 inch diameter support ring.

14. The glass article of any one of claims 1-13 comprising a normalized deflection according to deflection x thickness x elastic modulus of greater than or equal to 80 GN, greater than or equal to 100 GN, or greater than or equal to 120 GN, greater than or equal to 140 GN, or greater than or equal to 150 GN.

15. A consumer electronic product, comprising: a housing having a front surface, a back surface, and side surfaces; electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and the glass article of any one of claims 1-14 disposed over the display.

16. A method of making a glass article, the glass article having opposing first and second surfaces defining a body having a thickness (t), the method comprising: exposing a glass substrate that contains an alkali metal oxide in a base composition to a first ion exchange (IOX-1) treatment including a first bath comprising one or more molten potassium salts for a first duration at a first temperature that is less than a strain point of the glass substrate; following the IOX-1, exposing the glass substrate to a second ion exchange (IOX-2) treatment including a second bath comprising an admixture of ion-exchangeable molten salts and optional scavenging additive for a second duration that is less than the first duration at a secondSP23-267 temperature that is greater than or equal to the first temperature and less than the strain point; and following the IOX-2, exposing the glass substrate to a third ion exchange (IOX-3) treatment including a third bath comprising one or more molten potassium salts for a third duration that is less than the first duration at a third temperature that is less than the first temperature.

17. The method of claim 16, wherein: the first bath comprises greater than or equal to 90% by weight of potassium nitrate (KNO3) and less than or equal to 10% by weight of sodium nitrate (NaNO3); the admixture of the ion-exchangeable molten salts of the second bath comprises potassium nitrate (KNO3) and sodium nitrate (NaNO3) and a sodium-to-potassium (Na:K) ratio of greater than 1; and the third bath comprises by weight: 0 to less than or equal to 15% potassium carbonate (K2CO3) and potassium nitrate (KNO3) to total 100 wt. % and / or the first duration is greater than or equal to 5 hours and less than or equal to 50 hours; the second duration is greater than or equal to 0.5 hours and less than or equal to 2 hours; and the third duration is greater than or equal to 1 hours and less than 15 hours and / or the first temperature is greater than or equal to 400°C and less than or equal to 500°C; the second temperature is greater than or equal to 400°C and less than or equal to 550°C; and the third temperature is greater than or equal to 350°C and less than 450°C.

18. The method of claim 16, wherein the second bath comprises by weight: greater than or equal to 5 % to less than or equal to 45 % potassium nitrate (KNO3) and greater than or equal to 55 % to less than or equal to 95 % sodium nitrate (NaNO3) to total 100 wt. %.SP23-267 19. The method of claim 16, which excludes any thermal relaxation step that is in the absence of a molten salt bath between the IOX-1 and the IOX-3.

20. The method of claim 16, wherein the glass substrate comprises: a soda lime silicate composition; an alkali-alumino silicate composition; an alkali-containing borosilicate composition; an alkali-containing aluminoborosilicate composition, or an alkali-containing phosphate composition, optionally wherein the glass substrate comprises a central composition comprising: a Na2O / Li2O molar ratio in a range of greater than or equal to 1.5 to less than or equal to 2.1, and / or: about 50 mol% to about 69 mol% SiO2; about 12.5 mol% to about 25 mol% Al2O3; about 0 mol% to about 8 mol% B2O3; about 0.01 mol% to about 2 mol% K2O; about 11.0 mol% to about 15.0 mol% Na2O; and about 0.5 mol% to about 10 mol% Li2O.

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