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KR-102962602-B1 - Glass-based articles including a stress profile comprising two regions, and methods of making

KR102962602B1KR 102962602 B1KR102962602 B1KR 102962602B1KR-102962602-B1

Abstract

A glass-based article is disclosed comprising a first surface defining a thickness (t) and a second surface opposite to the first surface, and a stress profile, having a thickness (t) of about 3 millimeters or less, wherein, in the thickness range of about 0·t to 0.3·t and exceeding 0.7·t, all points of the stress profile include tangents having a slope of less than about -0.1 MPa/micrometer or greater than about 0.1 MPa/micrometer. Additionally, a glass-based article having a thickness (t) in the range of 0.1 mm to 2 mm is disclosed; and herein, at least one point of the stress profile in a first thickness range of about 0·t to 0.020·t and exceeding 0.98·t comprises a tangent having a slope of about -200 MPa/micrometer to about -25 MPa/micrometer or about 25 MPa/micrometer to about 200 MPa/micrometer, and herein, all points of the stress profile in a second thickness range of about 0.035·t to less than 0.965·t comprise a tangent having a slope of about -15 MPa/micrometer to about 15 MPa/micrometer.

Inventors

  • 그로스, 티모시 마이클
  • 구오, 시아오주
  • 오람, 파스칼
  • 레이만, 케빈 베리
  • 루세브, 로스티스라브 뱃체브
  • 슈나이더, 비터 마리노
  • 윌란테윅즈, 트레버 에드워드

Assignees

  • 코닝 인코포레이티드

Dates

Publication Date
20260508
Application Date
20170407
Priority Date
20160408

Claims (13)

  1. A first surface defining a thickness (t) in the range of 0.1 to 2 mm and a second surface opposite to the first surface; center plane; and A glass-based article comprising a stress profile extending along thickness (t) according to a mathematical formula that is a function of thickness (t), Here, at least one point of the mathematical formula for the stress profile in the first thickness range exceeding 0·t to 0.020·t and 0.98·t includes a tangent having a slope of -200MPa/micrometer to -25MPa/micrometer or 25MPa/micrometer to 200MPa/micrometer, and Here, all points of the mathematical formula for the stress profile in the second thickness range of 0.035·t to less than 0.965·t include tangents having a slope of -15 MPa/micrometer to 15 MPa/micrometer, wherein the mathematical formula for the stress profile according to the second thickness range forms a power-law function having a power exponent, where the power exponent is 1.2 to 3.2, The above stress profile is a glass-based article comprising a surface compressive stress of 300 MPa to 1100 MPa and a maximum central tension of 50 MPa or more.
  2. In claim 1, The above stress profile is a glass-based article including a depth of compression in the range of 0.1·t to 0.25·t.
  3. In claim 1, The above glass-based article further comprises a maximum center tension of 80 MPa or less.
  4. In claim 1, A glass-based article in which all points of the stress profile of the second thickness range include tangents having a slope of -2 MPa/micrometer to 2 MPa/micrometer.
  5. In claim 1, A glass-based article, wherein the first thickness range extends from 0.02·t to 0.025·t and from greater than 0.975·t to 0.98·t, and all points of the mathematical formula of the stress profile in the extended first thickness range comprise a tangent having a slope of -200 MPa/micrometer to -25 MPa/micrometer or 25 MPa/micrometer to 200 MPa/micrometer.
  6. In claim 5, A glass-based article, wherein the first thickness range is further extended from 0.025·t to 0.035·t and from 0.965·t to 0.975·t, and all points of the mathematical formula of the stress profile in the further extended first thickness range comprise tangents having a slope of -200 MPa/micrometer to -25 MPa/micrometer or 25 MPa/micrometer to 200 MPa/micrometer.
  7. In any one of claims 1-6, A glass-based article having a thickness (t) of 1 mm or less, a surface compressive stress of 500 MPa or more, and a depth of compression of 0.14·t or more.
  8. In any one of claims 1-6, The above glass-based article is a glass-based article further comprising potassium DOL extending over a first thickness range.
  9. In any one of claims 1-6, (i) The Knoop scratch threshold of the above glass-based article is greater than 10N and less than 16N; (ii) The above glass-based article has a survival rate of 40% to 100% when impacted with a force of 400 N or more according to a surface impact threshold test using 180 grit abrasive; and (iii) The above glass-based article is at least one of the following: capable of withstanding an edge impact of greater than 0.68 J and less than 1.58 J, or an edge impact of greater than 300 N and less than 500 N, according to an edge impact threshold test using a 30 grit abrasive.
  10. In any one of claims 1-6, The above glass-based article comprises a center plane, and the center plane comprises a composition comprising 2 mol% to 20 mol% of Li₂O .
  11. In claim 10, The above center-plane is a glass-based article further comprising a composition containing 0.5 mol% to 20 mol% of Na₂O .
  12. In claim 11, The above glass-based article is a glass-based article comprising a composition containing 0.5 mol% to 10 mol% of P₂O₅ .
  13. In any one of claims 1-6, A glass-based article having a surface compressive stress in the range of 690 MPa to 1100 MPa.

Description

Glass-based articles including a stress profile comprising two regions, and methods of making This application claims priority to U.S. provisional patent application No. 62/320,109 filed April 8, 2016, the entire contents of which are incorporated herein by reference. The present disclosure relates to glass-based articles exhibiting improved damage resistance, including improved fracture resistance, and more specifically, to fusion-formable glass and glass-ceramic articles exhibiting a non-zero metal oxide concentration gradient or concentration that varies along the thickness of the substantial part. The present disclosure also relates to glass-based articles comprising a stress profile including two regions having varying tangents. Glass-based articles often experience severe impacts that can introduce large flaws into the surface of the article. These flaws can extend to a depth of about 200 micrometers from the surface. Traditionally, thermally tempered glass has been used to prevent breakage caused by the introduction of said flaws into the glass, because thermally tempered glass often exhibits a large compressive stress (CS) layer (e.g., about 21% of the total thickness of the glass) that can prevent these flaws from propagating further into the glass and thus prevent breakage. An example of a stress profile generated by thermal tempering is shown in FIG. 1. In FIG. 1, a thermally treated glass article (100) comprises a first surface (101), a thickness ( t1 ), and a surface CS (110). A thermally treated glass article (100) exhibits a CS that decreases from a first surface (101) to a depth of compression (DOC) (130) as defined herein, at which point the stress changes from compressive stress to tensile stress and reaches a maximum center of tension (CT) (120). Since a sufficient thermal gradient must be formed between the core and the surface of such articles to achieve thermal strengthening and desired residual stress, thermal tempering is currently limited to thick glass-based articles (i.e., glass-based articles with a thickness of about 3 millimeters or more ( t1 )). Such thick articles are undesirable or impractical in many applications, such as displays (e.g., mobile phones, tablets, computers, navigation systems, and similar consumer electronics), construction articles (e.g., windows, shower panels, countertops, etc.), transportation articles (e.g., automobiles, trains, aircraft, marine vessels, etc.), home appliances, or any application requiring articles that are thin and lightweight but have excellent fracture resistance. Although chemical strengthening is not limited by the thickness of the glass-based article in the same way as thermal tempering, known chemically strengthened glass-based articles do not exhibit the stress profile of a thermally tempered glass-based article. An example of a stress profile generated by chemical strengthening (e.g., by an ion exchange process) is shown in FIG. 2. In FIG. 2, the chemically strengthened glass-based article (200) comprises a first surface (201), a thickness ( t2 ), and a surface CS (210). The glass-based article (200) exhibits a CS that decreases from the first surface (201) to DOC (230) as defined herein, at which point the stress changes from compressive stress to tensile stress and reaches a maximum CT (220). As shown in FIG. 2, this profile exhibits a CT region that is substantially flat or has a CT region with constant or nearly constant tensile stress along at least a portion of the CT region. Often, known chemically strengthened glass-based articles exhibit lower maximum CT values compared to the maximum center value shown in Fig. 1. FIG. 1 is a cross-sectional view across the thickness of a known thermally tempered glass article; FIG. 2 is a cross-sectional view across the thickness of a known chemically strengthened glass article; FIG. 3 is a cross-sectional view across the thickness of a chemically reinforced glass-based article according to one or more embodiments of the present disclosure; FIG. 4 is a schematic cross-sectional view of a ring-on-ring apparatus; FIG. 5 is a graph showing the maximum CT values for Examples 1A-1G as a function of ion exchange time; FIG. 6 is a graph showing the measured stress of Example 1E as a function of the depth extending from the surface of the glass-based article of Example 1E into the glass-based article; FIG. 7 is a graph showing the load for the breakage value of a glass-based article according to Example 2A after being worn down by different loads or pressures; FIG. 8 is a graph showing the height of breakage of a glass-based article according to Example 2A after it is dropped onto 180-grit sandpaper and then onto 30-grit sandpaper; FIG. 9 is a graph showing the height of breakage after a glass-based article according to Example 3A and Comparative Example 3B is dropped onto 30-grit sandpaper; FIG. 10 is a graph comparing the average load for breakage of glass-based articles according to Example