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KR-102963909-B1 - Glass-based articles including a metal oxide concentration gradient

KR102963909B1KR 102963909 B1KR102963909 B1KR 102963909B1KR-102963909-B1

Abstract

It includes a first surface and a second surface facing the first surface and having a thickness of about 3 millimeters or less (e.g., about 1 millimeter or less), and a stress profile, wherein, from about 0* t An embodiment of a glass-based product is disclosed in which all points of the stress profile between thickness ranges up to 0.3* t and from greater than 0.7* t to t include a tangent having a slope with an absolute value greater than about 0.1 MPa/micrometer. In some embodiments, the glass-based product includes a non-zero metal oxide concentration that varies along at least a portion of the thickness (e.g., from 0* t to about 0.3* t ) and a maximum central tension in the range of about 80 MPa to about 100 MPa. In some embodiments, the concentration of the metal oxide or alkali 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 may be about 0.05 mol% or more or 0.5 mol% or more over the thickness. A method for forming such a glass-based product is also disclosed.

Inventors

  • 데네카, 매튜 존
  • 고메즈, 시누
  • 후, 광글리
  • 스미스, 찰렌 마리
  • 탕, 중즈히
  • 티에제, 스티븐 알빈

Assignees

  • 코닝 인코포레이티드

Dates

Publication Date
20260512
Application Date
20170407
Priority Date
20160408

Claims (10)

  1. As a glass-based product, It includes a first surface and a second surface facing the first surface and defining the thickness ( t ) of the glass-based product, The surface CS is 200 MPa or higher; The depth of compression (DOC) is 0.14·t or greater and 0.25·t or less; The maximum CT is 80 MPa or higher and 95 MPa or lower; The maximum CT is located in the range of 0.4*t or greater and 0.6*t or less; and A glass-based product in which the concentration of the metal oxide is non-zero and varies over a thickness range of about 0*t to about 0.3*t, wherein the metal oxide comprises Li₂O , Na₂O , or K₂O .
  2. In claim 1, The above metal oxide is a glass-based product, Na₂O .
  3. In claim 1, A glass-based product having a thickness range of the metal oxide concentration of about 0*t to about 0.4*t.
  4. In claim 1, A glass-based product in which 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 the value to the second surface.
  5. In any one of claims 1-4, The above glass-based product 40 mol% or more and 80 mol% or less of SiO2 ; 0 mol% or more and 4 mol% or less of Na₂O ; Less than 1 mol% K₂O ; Containing 0 mol% or more and 5 mol% or less of ZrO2 , The ratio of Li₂O (mol%) to R₂O (mol%) in the glass-based product is 0.7 to 1.0, where R₂O is the sum of Li₂O , Na₂O , and K₂O in the glass-based product.
  6. In any one of claims 1-4, The above glass-based product is a glass-based product comprising a CT to CS ratio in the range of 0.1 to 0.8.
  7. In any one of claims 1-4, The above glass-based product is a glass-based product having a thickness of about 1 mm or less.
  8. In any one of claims 1-4, The above glass-based product is a glass-based product comprising a surface CS of 200 MPa or more and 400 MPa or less.
  9. In any one of claims 1-4, The CT region is a glass-based product containing metal oxides.
  10. In any one of claims 1-4, The above glass-based product is a glass-based product having a liquid viscosity of less than 100 kP.

Description

Glass-based articles including a metal oxide concentration gradient This application enjoys the benefit of priority to U.S. Provisional Application No. 62/366338 filed July 25, 2016, and U.S. Provisional Application No. 62/320077 filed April 8, 2016, under 35 U.S.C. § 119, the contents of which are incorporated herein in their entirety. The present invention relates to glass-based products exhibiting improved damage resistance, including improved fracture resistance, and more specifically, to glass and glass ceramics exhibiting a non-zero metal oxide concentration gradient or concentration that varies along a substantial portion of the thickness. Glass-based products often experience severe impacts that can introduce large flaws into the surface of the product. These flaws can extend from the surface to a depth of about 200 micrometers (microns or μm). Typically, thermally 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 flaws from propagating further into the glass and thus prevent failure; therefore, thermally tempered glass has been used to prevent failures caused by the introduction of these flaws into the glass. An example of a stress profile generated by thermal tempering is shown in FIG. 1. In FIG. 1, a heat-treated glass product (100) comprises a first surface (101), a thickness (t1 ) , and a surface CS (110). The heat-treated glass product (100) exhibits a CS in which, from the first surface (101), the stress depth changes from compression to tensile stress as defined herein and decreases to a depth of compression (DOC) (130) reaching a maximum center of tension (CT) (120). Thermal strengthening is currently limited to thick glass-based products (i.e., glass-based products with a thickness t1 of 3 millimeters or more) because a sufficient thermal gradient must be formed between the core and surface of these products to achieve thermal strengthening and desired residual stress. Such thick products are undesirable or impractical in many applications, such as displays (e.g., consumer electronics including mobile phones, tablets, computers, navigation systems, and similar products), construction (e.g., windows, shower panels, countertops, etc.), transportation (e.g., automobiles, trains, spacecraft, ocean-going vessels, etc.), home appliances, or any application requiring products with excellent fracture resistance and thin, lightweight properties. Although chemical strengthening is not limited by the thickness of the glass-based product in the same way as thermal strengthening, known chemically strengthened glass-based products do not exhibit the stress profile of thermally strengthened glass-based products. An example of a stress profile produced by chemical strengthening is shown in FIG. 2. In FIG . 2, the chemically strengthened glass-based product (200) comprises a first surface (201), a thickness ( t2 ), and a surface CS (210). The glass-based product (200) exhibits a CS from the first surface (201) that decreases from the stress depth, as defined herein, from compression to tensile stress, reaching a maximum CT (220) and a DOC (230). As shown in FIG. 2, this profile represents a substantially flat CT region or CT region having a constant or nearly constant tensile stress along at least a portion of the CT region. Often, known chemically strengthened glass-based products exhibit a lower maximum CT value compared to the maximum center value shown in Fig. 1. FIG. 1 is a cross-sectional view across the thickness of a known heat-strengthened glass product; FIG. 2 is a cross-sectional view across the thickness of a known chemically strengthened glass product; FIG. 3 is a cross-sectional view across the thickness of a chemically strengthened glass-based product according to one or more embodiments of the present invention; FIG . 4 is a graph showing various stress profiles according to one or more embodiments of the present invention; FIG . 5 is a schematic cross-sectional view of a ring-on-ring device; FIG. 6 is a schematic cross-sectional view of one embodiment of a device used to perform an inverted sphere on the sandpaper (IBoS) test described herein; FIG. 7 is a schematic cross-sectional view of the main mechanism of failure caused by damage introduction plus bending that typically occurs in glass-based products used in handheld electronic devices or mobile electronic devices; FIG. 8 is a process flow diagram of a method for performing an IBoS test in the apparatus disclosed herein; FIG. 9 is a graph showing the concentration of Na₂O in a glass-based product according to one or more embodiments of the present invention and a known chemically strengthened glass-based product; FIG . 10 is a graph showing CT values and DOC values as a function of ion exchange time according to one or more embodiments of the present invention; FIG. 11 is a graph comparing stress profiles as a function of depth of a glass-ba