A type of microcrystalline glass, chemically strengthened microcrystalline glass, cover glass, and electronic equipment.

Abstract

This application provides a microcrystalline glass, a chemically strengthened microcrystalline glass, a cover glass, and an electronic device, belonging to the field of microcrystalline glass technology. This application achieves this by ensuring the microcrystalline glass meets specific composition and crystal phase structure requirements, ensuring the content and ratio of each component within a specific range, and ensuring specific molar percentage relationships between Na₂O, B₂O₃, ZrO₂, or Li₂O. Simultaneously, it ensures that the microcrystalline glass uses lithium disilicate as the main crystal phase. This not only endows the microcrystalline glass with excellent optical properties and high intrinsic strength but also enables the rapid and efficient production of chemically strengthened microcrystalline glass with high stress levels and high mechanical strength under conventional chemical strengthening processes.

Description

Technical Field

[0001] This application relates to the field of glass-ceramic technology, and more specifically, to a glass-ceramic, a chemically strengthened glass-ceramic, a cover glass, and an electronic device. Background Technology

[0002] Glass-ceramics are solid composite materials formed by controlled crystallization of a base glass during heat treatment. Glass-ceramics contain both microcrystalline and glassy phases. Compared to glass materials without microcrystalline phases, glass-ceramics typically have higher strength. This is because the microcrystalline phase has higher strength than the glassy phase, absorbs more energy during fracture, and can extend the crack propagation path, thus hindering crack growth and consuming more impact energy during fracture.

[0003] In recent years, glass-ceramics have been increasingly used in various electronic devices, such as mobile phones, watches, tablets, laptops, e-readers, or other similar devices, as cover glass for electronic devices, such as cover glass for displays and back covers. For displays in electronic devices, cover glass is generally required to have good optical properties, as well as a thin thickness and high mechanical properties. To further improve the mechanical properties of glass-ceramics, chemical strengthening treatment is usually required, through ion exchange, to produce chemically strengthened glass-ceramics with higher stress levels, higher mechanical strength, and higher damage resistance.

[0004] Therefore, how to improve the chemical strengthening effect of glass-ceramics while satisfying excellent optical performance, and achieve rapid and efficient preparation of chemically strengthened glass-ceramics with high stress levels and high mechanical strength, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] Because the structure of glass-ceramics differs from that of glass materials without microcrystalline phases, the difficulty of chemical strengthening also differs. To prepare high-strength chemically strengthened glass-ceramics with high stress levels and mechanical strength, while meeting the optical performance requirements of cover glass applications, those skilled in the art typically choose to perform extended chemical strengthening treatments on existing glass-ceramics, or use high-temperature (e.g., exceeding 480°C) molten salt baths for chemical strengthening. Both extending the strengthening time and increasing the molten salt bath temperature lead to an increase in the cost of chemical strengthening of glass-ceramics, i.e., an increase in the manufacturing cost of high-strength chemically strengthened glass-ceramics.

[0006] The purpose of this application is to provide a glass-ceramic with excellent optical properties and high intrinsic strength by adjusting the composition and structure of the glass-ceramic. This glass-ceramic can be rapidly and efficiently prepared under conventional chemical strengthening process conditions to obtain a chemically strengthened glass-ceramic with high stress level, excellent mechanical strength, and excellent damage resistance.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] In a first aspect, a microcrystalline glass is provided, the microcrystalline glass containing a lithium disilicate crystalline phase, wherein the lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the microcrystalline glass;

[0009] The microcrystalline glass comprises, by molar percentage of oxides: SiO2: 61.50%–63.40%, Al2O3: 2.75%–2.99%, P2O5: 0.91%–1.91%, ZrO2: 4.20%–4.85%, Na2O: 1.80%–3.20%, B2O3: 0%–1.00%, and Li2O: 25.32%–26.52%.

[0010] Furthermore, in the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O], B2O3 [B2O3], and ZrO2 [ZrO2] satisfy the following relationship:

[0011] Z = -1.344 × (2.65 - 100 × [Na2O])2 + 0.466 × 100 × [B2O3] + 1.203 × 100 × [ZrO2], 4.80 ≤ Z ≤ 5.35, preferably 4.98 ≤ Z ≤ 5.20.

[0012] By ensuring that the glass-ceramic meets specific composition and crystal phase structure requirements, and that the content and ratio of each component within a specific range, and that Na2O, B2O3, ZrO2, or Li2O meet specific molar percentage relationships, while simultaneously ensuring that lithium disilicate is the main crystal phase, not only can the glass-ceramic be endowed with excellent optical properties and high intrinsic strength, but it can also enable the rapid and efficient production of chemically strengthened glass-ceramics with high stress levels and high mechanical strength under conventional chemical strengthening processes.

[0013] As an optional implementation, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] in the composition of the microcrystalline glass satisfy the following relationship:

[0014] 0.90% ≤ [Na2O] - [B2O3] ≤ 3.10%, preferably 1.25% ≤ [Na2O] - [B2O3] ≤ 3.02%, more preferably 2.00% ≤ [Na2O] - [B2O3] ≤ 3.00%.

[0015] As an optional implementation, the molar percentages of Na2O [Na2O] and Li2O [Li2O] in the composition of the microcrystalline glass satisfy the following relationship:

[0016] 8.55≤[Li2O] / [Na2O]≤13.85, preferably 8.55≤[Li2O] / [Na2O]≤11.50.

[0017] As an optional implementation, the lithium disilicate phase accounts for more than 70% by weight of all crystalline phases of the glass-ceramic, preferably more than 85% by weight of all crystalline phases of the glass-ceramic.

[0018] As an optional implementation, the microcrystalline glass contains, by molar percentage of oxides:

[0019] The molar percentage of SiO2 is 61.50% to 63.30%, preferably 62.00% to 62.60%; and / or,

[0020] The molar percentage of P2O5 is 1.20% to 1.91%, preferably 1.30% to 1.60%; and / or,

[0021] The molar percentage of Na₂O is 1.85% to 3.05%, preferably 2.20% to 3.00%; and / or,

[0022] The molar percentage of B2O3 is 0–0.65%; and / or, the molar percentage of ZrO2 is 4.20%–4.80%; and / or,

[0023] The molar percentage of Li2O is 25.52% to 26.52%, preferably 25.52% to 26.00%.

[0024] As an optional implementation, the microcrystalline glass contains, by molar percentage of oxides:

[0025] The molar percentage of SiO2 is 62.88%, 63.30%, 62.50%, 63.26%, 62.38%, 62.27%, 62.45%, 62.22%, or 63.17%; and / or,

[0026] The molar percentage of Al2O3 is 2.86%, 2.87%, 2.93%, 2.94%, or 2.99%; and / or,

[0027] The molar percentage of P2O5 is 1.00%, 1.20%, 1.30%, 1.60%, 1.40%, 1.41%, 1.53%, or 1.54%; and / or,

[0028] The molar percentage of ZrO2 is 4.80%, 4.74%, 4.84%, 4.33%, 4.34%, or 4.35%; and / or,

[0029] The molar percentage of Na₂O is 1.85%, 2.35%, 1.95%, 2.36%, 2.96%, 3.01%, 2.93%, or 2.95%; and / or,

[0030] The molar percentages of Li2O are 25.62%, 25.82%, 25.69%, 25.36%, 25.77%, 25.87%, 25.90%, 25.79%, 26.03%, or 25.74%.

[0031] As an optional implementation, the composition of the glass-ceramic, expressed as a molar percentage of oxides, satisfies the following:

[0032] The value of equation Z is 5.19, 5.10, 5.09, 5.06, or 5.13; and / or,

[0033] The values ​​of [Na₂O]-[B₂O₃] are 1.26%, 1.79%, 0.96%, 2.36%, 2.96%, 3.01%, 2.93%, or 2.95%; and / or,

[0034] The values ​​of [Li2O] / [Na2O] are 13.83, 10.93, 13.01, 10.92, 8.73, 8.61, 8.79 or 8.83.

[0035] As an optional implementation, the crystallinity of the glass-ceramic is not less than 45%, preferably, the crystallinity of the glass-ceramic is 45% to 85%, more preferably, the crystallinity of the glass-ceramic is 55% to 65%; and / or,

[0036] In the microcrystalline glass, the average grain size does not exceed 100 nm, preferably, the average grain size does not exceed 40 nm, and more preferably, the average grain size is 15 to 30 nm.

[0037] As an optional implementation, the microcrystalline glass is transparent in the visible light wavelength range. Preferably, at a thickness of 0.70 mm, the transmittance of the microcrystalline glass for 550 nm wavelength light is ≥90.00%, more preferably >90.40%; and / or, at a thickness of 0.70 mm, the haze of the microcrystalline glass is <0.30%.

[0038] As an optional implementation, the b-value of the microcrystalline glass is <0.70 at a thickness of 0.70 mm, preferably b-value ≤0.60.

[0039] As an optional implementation, the Young's modulus of the microcrystalline glass is ≥100 GPa, preferably, the Young's modulus of the microcrystalline glass is 105–112.50 GPa; and / or,

[0040] The Vickers hardness of the microcrystalline glass is ≥640 kgf / mm². 2 Preferably, the Vickers hardness of the microcrystalline glass is 640–680 kgf / mm². 2 .

[0041] As an optional implementation, the microcrystalline glass includes planar microcrystalline glass or curved microcrystalline glass; preferably, when the microcrystalline glass is curved microcrystalline glass, the microcrystalline glass can be obtained by 3D hot bending forming of crystallized glass raw material with a crystallinity of not less than 5%.

[0042] As an optional implementation, the microcrystalline glass is obtained by heat treatment of a substrate glass. Preferably, the heat treatment process includes nucleation treatment and / or crystallization treatment. Preferably, the crystallization treatment includes one-step crystallization treatment or two-step crystallization treatment. Preferably, curved microcrystalline glass can be prepared by two-step crystallization treatment. When two-step crystallization treatment is used, the second crystallization treatment is to heat the crystallized glass raw material obtained from the first crystallization treatment to the crystallization temperature and perform 3D hot bending forming treatment.

[0043] As an optional implementation, the thickness of the microcrystalline glass is 0.10 to 5.00 mm.

[0044] In a second aspect, a chemically strengthened glass-ceramic is provided, which is obtained by chemically strengthening the glass-ceramic described in any embodiment of the first aspect. The composition at the center of the chemically strengthened glass-ceramic is the same as that of the glass-ceramic described in any embodiment of the first aspect. The chemically strengthened glass-ceramic includes a compressive stress layer region extending from the surface of the chemically strengthened glass-ceramic to a compression depth, and has tensile stress inside the chemically strengthened glass-ceramic.

[0045] As an optional implementation, the chemically strengthened glass-ceramic comprises a lithium disilicate crystalline phase, wherein the lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the chemically strengthened glass-ceramic; the composition at the center of the chemically strengthened glass-ceramic, based on the molar percentage of oxides, includes: SiO2: 61.50%–63.40%, Al2O3: 2.75%–2.99%, P2O5: 0.91%–1.91%, ZrO2: 4.20%–4.85%, Na2O: 1.80%–3.20%, B2O3: 0–1.00%, and Li2O: 25.32%–26.52%.

[0046] Furthermore, in the composition at the center of the chemically strengthened glass crystal, the molar percentages of Na2O [Na2O], B2O3 [B2O3], and ZrO2 [ZrO2] satisfy the following relationship:

[0047] Z = -1.344 × (2.65 - 100 × [Na2O])2 + 0.466 × 100 × [B2O3] + 1.203 × 100 × [ZrO2], 4.80 ≤ Z ≤ 5.35, preferably 4.98 ≤ Z ≤ 5.20.

[0048] As an optional implementation, in the composition at the center of the chemically strengthened glass crystal, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] satisfy the following relationship:

[0049] 0.90% ≤ [Na₂O] - [B₂O₃] ≤ 3.10%, preferably 1.25% ≤ [Na₂O] - [B₂O₃] ≤ 3.02%, more preferably 2.00% ≤ [Na₂O] - [B₂O₃] ≤ 3.00%; and / or,

[0050] In the composition at the center of the chemically strengthened glass crystal, the molar percentages of Na₂O [Na₂O] and Li₂O [Li₂O] satisfy the following relationship:

[0051] 8.55≤[Li2O] / [Na2O]≤13.85, preferably 8.55≤[Li2O] / [Na2O]≤11.50.

[0052] As an optional implementation, the chemically strengthened glass-ceramic has a CT_LD of 45,000–55,000 MPa / mm², where CT_LD is the tensile stress linear density; preferably, the chemically strengthened glass-ceramic has a CT_LD of 48,000–53,000 MPa / mm²; and / or,

[0053] The chemically strengthened glass-ceramic has a DOL_0 of 0.18t to 0.25t, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic. Preferably, the chemically strengthened glass-ceramic has a DOL_0 of 0.20t to 0.25t; and / or,

[0054] The chemically strengthened glass-ceramic has a CS_50 of 150–199 MPa, where CS_50 refers to the compressive stress value at a depth of 50 μm measured from the main surface of the chemically strengthened glass-ceramic. Preferably, the chemically strengthened glass-ceramic has a CS_50 of 160–199 MPa; and / or,

[0055] The chemically strengthened microcrystalline glass has a |CT_AV| of 80–98 MPa, where |CT_AV| is the absolute value of the average tensile stress; and / or,

[0056] The chemically strengthened glass-ceramic has a |CT_CV| of 115–142 MPa, where |CT_CV| is the absolute value of the maximum tensile stress. Preferably, the chemically strengthened glass-ceramic has a |CT_CV| of 120–140 MPa.

[0057] As an optional implementation, the chemically strengthened glass-ceramic has a Vickers hardness greater than or equal to 680 kgf / mm². 2 Preferably, the Vickers hardness of the chemically strengthened microcrystalline glass is 700 kgf / mm. 2 ~800kgf / mm 2 .

[0058] Thirdly, a glass device is provided, the glass device comprising a microcrystalline glass as described in any embodiment of the first aspect or a chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0059] Fourthly, a cover glass is provided, which is made of microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect. The cover glass can be a display screen cover, back cover, or camera protective cover for an electronic device.

[0060] Fifthly, an electronic device is provided, the electronic device comprising a microcrystalline glass as described in any embodiment of the first aspect or comprising a chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0061] As an alternative implementation, the electronic device includes a housing assembled on the outside of the electronic device and a circuit board located inside the housing, the housing being made of microcrystalline glass as described in any embodiment of the first aspect or of chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0062] As an alternative implementation, the housing includes a display cover assembled on the front side of the electronic device, the display cover comprising microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0063] As an alternative implementation, the housing includes a rear cover assembled to the rear side of the electronic device, the rear cover being made of microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0064] As an optional implementation, the electronic device further includes a camera assembly located inside the housing, the housing including a camera protective cover covering the camera assembly, the camera protective cover being made of microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0065] As an optional implementation, the electronic device further includes a mid-frame located between the display module and the housing, the mid-frame comprising microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0066] In some embodiments, the outer casing may be partially or entirely made of microcrystalline glass or chemically strengthened microcrystalline glass. The electronic device in this application may have one or more components, such as the display screen cover, back cover, camera protective cover, and mid-frame, made of microcrystalline glass as described in any embodiment of the first aspect or chemically strengthened microcrystalline glass as described in any embodiment of the second aspect.

[0067] One or more of the above-mentioned technical solutions provided in this application have the following advantages compared with the prior art:

[0068] This application achieves specific composition and crystal phase structure for the glass-ceramic, ensuring that the content and ratio of each component within the glass-ceramic meet specific ranges, and that Na2O, B2O3, ZrO2, or Li2O meet specific molar percentage relationships. Simultaneously, it ensures that lithium disilicate is the primary crystal phase. This not only endows the glass-ceramic with excellent optical properties and high intrinsic strength but also enables the rapid and efficient production of chemically strengthened glass-ceramics with high stress levels and high mechanical strength under conventional chemical strengthening processes. This effectively reduces the manufacturing cost of high-strength chemically strengthened glass-ceramics. Attached Figure Description

[0069] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 The image shows the XRD pattern of the microcrystalline glass of Example 2.

[0071] Figure 2 The transmittance curve of the microcrystalline glass in Example 2 in the 360nm-740nm wavelength range is shown.

[0072] Figure 3 This is a comparison of the XRD patterns of the microcrystalline glass in Example 2 before and after chemical strengthening.

[0073] Figure 4 This is a physical image of the microcrystalline glass of Example 2.

[0074] Figure 5 This is a photograph of the microcrystalline glass of Example 7.

[0075] Figure 6 This is a physical image of the microcrystalline glass in Comparative Example 5.

[0076] Figure 7 This is a physical image of the microcrystalline glass of Comparative Example 6.

[0077] Figure 8 This is a physical image of the microcrystalline glass of Comparative Example 8.

[0078] Figure 9 This is a schematic diagram of the front structure of an electronic device provided in an embodiment of this application.

[0079] Figure 10 This is a schematic diagram of the rear structure of an electronic device provided in an embodiment of this application.

[0080] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0081] Reference numerals: 1-Outer shell; 11-Display cover; 12-Rear cover; 13-Camera protective cover; 2-Camera assembly; 3-Middle frame; 4-Display module. Detailed Implementation

[0082] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0083] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the ranges, the endpoint values ​​of the ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "optional" mean that they may or may not be included (or may or may not be present). The term "and / or" as used herein is inclusive; for example, "A and / or B" means only A, or only B, or both A and B.

[0084] Terminology and testing methods:

[0085] In this application, glass-ceramics are solid composite materials that simultaneously contain a glassy phase and a crystalline phase (or microcrystalline phase, crystalline phase) prepared by targeted and controlled heat treatment of a substrate glass. Glass-ceramics are also known as glass ceramics.

[0086] In this application, chemically strengthened glass-ceramics refers to solid composite materials obtained by chemically strengthening glass-ceramics. It should be understood that during chemical strengthening, alkali metal ions with large ionic radii (e.g., potassium or sodium ions) in the molten salt bath (or molten salt bath) will replace alkali metal ions with small ionic radii (e.g., sodium or lithium ions) in the glass-ceramics, thereby generating a volume difference in exchange ions and producing compressive stress (or compressive stress) on the surface of the glass-ceramics.

[0087] In this application, the substrate glass refers to glass that has not undergone nucleation treatment, crystallization treatment, or strengthening treatment.

[0088] In this application, the composition at the center of the chemically strengthened glass crystal refers to the composition at or near the center of the depth of the chemically strengthened glass crystal.

[0089] In this application, the visible light wavelength range refers to 360nm to 740nm.

[0090] In this application, haze is the percentage of transmitted light intensity that deviates from the incident light by more than 2.5° to the total transmitted light intensity.

[0091] In this application, the main crystalline phase (or also called the primary crystalline phase) refers to a crystalline phase that has a higher weight content than other crystalline phases present in the glass-ceramic.

[0092] In this application, the main surface refers to the surface with the largest surface area in a glass brick or glass sheet, such as the upper or lower surface of a microcrystalline glass sheet.

[0093] In this application, crystallinity refers to the percentage of the total mass of crystalline phases or crystals in the glass-ceramic to the total mass of the glass-ceramic, or the total content of crystalline phases in the glass-ceramic.

[0094] In this application, when light of a certain wavelength is irradiated onto the main surface of the microcrystalline glass, the light will be reflected, absorbed, and transmitted. The ratio of the intensity of the transmitted portion to the intensity of the incident light is the transmittance.

[0095] In this application, the D65 light source is a light source with a color temperature of 6500K, a color rendering index Ra greater than 90, and is used for measuring the color of objects illuminated by sunlight that includes the ultraviolet region, and displays a broad spectral distribution in the visible wavelength region.

[0096] In this application, crystallized glass raw material refers to glass raw material that has undergone heat treatment for a period of time, so that the glass has reached a certain degree of crystallinity, but has not yet reached the target degree of crystallinity, and can continue to crystallize to reach the target degree of crystallinity when heated.

[0097] In this application, CT_LD refers to the tensile stress linear density, with units of MPa / mm. It should be understood that after the glass-ceramic is placed in a molten salt bath for ion exchange, a compressive stress layer (or compressive stress layer) is formed on the surface of the glass-ceramic, while a tensile stress layer (or tensile stress layer) is formed inside the glass-ceramic. For example, during chemical strengthening treatment, large-radius alkali metal ions in the molten salt bath exchange ions with small-radius alkali metal ions in the glass-ceramic, thereby forming a compressive stress layer on the surface of the glass-ceramic and a tensile stress layer inside the glass-ceramic. That is, a chemically strengthened glass-ceramic containing both a compressive stress layer and a tensile stress layer is prepared. In this application, CT_LD is calculated using the following formula:

[0098]

[0099] Where t represents the thickness of the chemically strengthened glass-ceramic, in mm; DOL_0 represents the compressive stress layer depth of the chemically strengthened glass-ceramic, in μm; and |CT_AV| represents the absolute value of the average tensile stress of the chemically strengthened glass-ceramic, in MPa. It should be understood that the calculation formula for the tensile stress linear density involves substituting the data according to the above unit requirements to obtain the calculation result; the units themselves are not included in the calculation.

[0100] In this application, CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic, in MPa, obtained by testing with an SLP-2000 stress meter.

[0101] In this application, |CT_AV| refers to the absolute value of the average tensile stress, in MPa. Specifically, it refers to the absolute value of the average value of all tensile stresses in the tensile stress layer, which is obtained by testing with an SLP-2000 stress meter.

[0102] In this application, |CT_CV| refers to the absolute value of the maximum tensile stress, in MPa. Specifically, it refers to the absolute value of the maximum value among all tensile stresses in the tensile stress layer, obtained by testing with an SLP-2000 stress meter.

[0103] In this application, DOL_0 refers to the compressive stress layer depth, or the compressive stress layer depth, specifically the distance from any main surface of the chemically strengthened glass-ceramic to a position close to the zero compressive stress on that surface, obtained by testing with an SLP-2000 stress meter.

[0104] In this application, the aforementioned stress performance testing method is as follows: An SLP 2000 (Luceo, Japan) stress meter is used to test the |CT_CV|, DOL_0, and |CT_AV| of the chemically strengthened glass-ceramic. The relevant parameter settings for the stress meter are: light source wavelength of 518 nm, SOC (photoelastic coefficient) set to 26 [(nm / cm) / MPa], refractive index set to 1.56, and exposure time: 300 μsec. Then, the tensile stress linear density (CT_LD) value of the chemically strengthened glass-ceramic is calculated using the aforementioned formula for calculating tensile stress linear density.

[0105] In this application, the b-value is used to characterize the yellow-blue value of the material. The b-value in this application is the transmitted light b-value, and a positive b-value indicates that the material has a bluish tint.

[0106] In this application, Vickers hardness refers to a standard for expressing the hardness of materials proposed by Robert L. Smith and George E. Sandland in 1921 at Vickers Ltd.

[0107] The Vickers hardness test method in this application is as follows: A small piece of microcrystalline glass or chemically strengthened microcrystalline glass with dimensions of 50mm × 50mm × 0.70mm is prepared. A clean glass sample without visible scratches, dents, cracks, or other damage is selected as the test sample. The Vickers hardness is then measured using a Vickers hardness tester. The Vickers hardness tester used in this application is the VTD405 digital display low-load Vickers hardness tester from Beijing Kewei Technology Co., Ltd. Test conditions: load 300gf, loading time 10s, and the validity of the indentation conforms to the standard "GB / T37900-2019 Test Method for Hardness and Fracture Toughness of Ultra-thin Glass: Low-load Vickers Hardness Indentation Method". Measurements are taken at three different locations on the surface of the same test sample, and the average of the three measurements is recorded as the Vickers hardness result of the test sample.

[0108] In this application, Young's modulus is used to characterize the ability of glass to resist elastic deformation under external forces. This application uses the UMS-100 ultrasonic material characterization system to test the Young's modulus of the glass-ceramic using acoustic waves.

[0109] In this application, nucleation treatment refers to the growth of small crystal nuclei from nucleating substances in a substrate glass through heat treatment; crystallization treatment refers to the growth of a certain crystal based on the crystal nuclei through heat treatment.

[0110] In this application, the thickness of the glass-ceramic was obtained by micrometer measurement. It should be understood that, along the thickness direction, the degree of ion exchange varies gradient from the surface to the center, and the total Na-K and / or Li-Na exchange capacity generally does not exceed 1.5% of the total sample mass, with ionic radius differences all at the micrometer (pm) level. Therefore, the expansion effect along the thickness direction is extremely slight, and the thickness can be approximated as essentially unchanged. That is, the thickness change of the glass-ceramic before and after chemical strengthening is very small and can be ignored.

[0111] In this application, the dimensions of the microcrystalline glass sheet were tested using a two-dimensional measuring machine (instrument model: Miyu MY-YXCL-4030).

[0112] In this application, the crystal phase, crystallinity, and average grain size of the glass-ceramic were confirmed by XRD testing. Specifically:

[0113] (1) XRD test: The microcrystalline glass or chemically strengthened microcrystalline glass of this application was crushed and ground into samples with a particle size of less than 75 μm. The ground samples were tested using an X-ray diffractometer to obtain XRD diffraction peak curves and XRD diffraction data. The X-ray diffractometer used in this application was a Shimadzu XRD-6100, the target material was copper, the incident angle range used in the test was 2θ=10°-50°, the scanning speed was 6° / min, the working voltage was 40kV, and the working current was 30mA.

[0114] (2) Determination of crystal phase: The crystal phase in the sample was determined by analyzing the XRD diffraction data using Jade software (JADE Standard 8.6).

[0115] (3) Determination of crystallinity: The crystallinity of the sample can be determined by importing the XRD test results (RAW format) into the Rietveld X-ray diffraction data refinement software Jade for fitting and calculation. Specifically, the ratio of the fitted crystal phase peak area to the total fitted peak area is recorded as the crystallinity of the sample.

[0116] (4) Determination of average grain size: Using the XRD test results, the average grain size (or average crystal size) of the sample can be calculated according to the Scherrer formula D = Kλ / (βcosθ). Where λ is the X-ray wavelength, λ = 0.154056 nm, β is the half-width at half-maximum (FWHM) of the diffraction peak, K = 0.89, and θ is the Bragg diffraction angle. Specifically, the RAW format file output by the XRD instrument is used for curve fitting in Jade software. Jade outputs a fitting report. Based on the angle 2θ value and Peak FWHM value corresponding to each diffraction peak in the fitting report, the Peak FWHM value is converted to radians: β = (FWHM / 180 × 3.14). The grain size of each diffraction peak is calculated using the Scherrer formula D = Kλ / (βcosθ), and then averaged to obtain the average grain size in the sample.

[0117] In this application, referring to the national standard GB / T 7962.12-2010 "Test Methods for Colorless Optical Glass - Part 12: Intraspectral Transmittance", a haze meter was used to test the transmittance, haze, and b-value of the microcrystalline glass of this application. Specifically, the transmittance, haze, and b-value of five microcrystalline glass pieces from the same batch for different wavelengths of light were tested using a haze meter. The average b-value and haze values ​​measured from the five microcrystalline glass pieces were recorded as the b-value result and haze result of the microcrystalline glass, respectively. The average transmittance of the five microcrystalline glass pieces measured at a wavelength of 550 nm was recorded as the transmittance result of the microcrystalline glass at a wavelength of 550 nm. The haze meter used in this application test is a Konica Minolta CM-3600A spectrophotometer with a transmission optical system, a planar refracting grating for beam splitting, a wavelength range of 360nm-740nm, a wavelength spacing of 10nm, and a pulsed xenon lamp ×4 for illumination. The ambient temperature where the instrument was placed was 24℃ and the air humidity was 40%.

[0118] In this application, among multiple chemically strengthened glass-ceramic samples from the same embodiment or comparative example, the drop height measured for each sample is summed, and the sum is divided by the number of samples tested. This sum is recorded as the average drop height measured for the tested chemically strengthened glass-ceramic, used to characterize the drop damage resistance of the chemically strengthened glass-ceramic. Specifically, at least 10 samples are taken from each batch for testing, and the average drop height measured is... Where n is the number of glass samples tested in each batch, and hi is the drop height against sandpaper test for a single sample.

[0119] The test method for the drop height resistance of a single sample against sandpaper is as follows:

[0120] Step 1: Attach 80-grit sandpaper to the lower surface of the 181g model machine and place the model machine on the Green Map LT-SKDL-CD drop tester;

[0121] Step 2: Place the chemically strengthened glass-ceramic sample (50mm x 50mm x 0.7mm) directly beneath the model machine, with the sample facing the sandpaper. Drop the model machine from a certain height, impacting the sample directly beneath it. If the sample does not break, gradually increase the drop height, continuing the impact until the sample breaks. For example, start with a drop height of 0.4m. If the sample does not break after one drop, increase the drop height by 0.1m and repeat the process until the sample breaks.

[0122] Step 3: Record the previous drop height of the chemically strengthened microcrystalline glass sample before it breaks as its sandpaper drop resistance height. For example, if the drop height is increased by 0.1m each time, and the drop height when the sample breaks is 0.5m, then the sandpaper drop resistance height of the sample is 0.4m.

[0123] Unrestricted by any particular theory, it is speculated that during the chemical strengthening of glass-ceramics, alkali metal ions in the glass phase primarily exchange ions with those in the molten salt bath, thereby forming a compressive stress structure on the surface of the glass-ceramics to further enhance their mechanical strength and damage resistance. While the dense grain structure within the glass-ceramics is beneficial for improving its intrinsic strength and damage resistance, the interconnected structure formed by these dense grains can confine the glass phase (or residual glass phase) between the grains. This hinders ion exchange pathways, preventing alkali metal ions in the glass phase from exchanging with those in the molten salt bath used for chemical strengthening. Consequently, it increases the difficulty of achieving high-stress performance through chemical strengthening of glass-ceramics, thus increasing the manufacturing difficulty of high-strength chemically strengthened glass-ceramics. In particular, lithium aluminum silicate glass systems are prone to precipitating non-single crystalline phases after heat treatment. The precipitated crystalline phases may include lithium disilicate, quartz, or lithium metasilicate. Non-single crystalline phase glass-ceramics often have higher crystallinity. The higher the crystal content, the more energy and time are required for ion diffusion. In other words, the non-single crystalline phase structure may further increase the difficulty of ion exchange in glass-ceramics.

[0124] In existing technologies, to prepare chemically strengthened glass-ceramics that meet application requirements, it is common practice to perform a relatively long chemical strengthening treatment on existing glass-ceramics, or to use a high-temperature (e.g., exceeding 480°C) molten salt bath for chemical strengthening. Both extending the strengthening time and increasing the temperature of the molten salt bath increase the cost of chemical strengthening of glass-ceramics, thus increasing the manufacturing cost of high-strength chemically strengthened glass-ceramics.

[0125] In view of this, and in order to improve economic efficiency, this application provides a microcrystalline glass that differs from existing technologies, possessing excellent optical properties and high intrinsic strength, and capable of achieving rapid ion exchange to obtain a high stress level. The microcrystalline glass of this application can be rapidly and efficiently prepared under conventional chemical strengthening process conditions to obtain chemically strengthened microcrystalline glass with high stress levels, excellent mechanical strength, and excellent damage resistance.

[0126] As described above, in some embodiments of this application, a microcrystalline glass is provided, which contains a lithium disilicate crystalline phase (Li2Si2O5), wherein the lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the microcrystalline glass; the composition of the microcrystalline glass, in molar percentage of oxides, includes: SiO2: 61.50%–63.40%, Al2O3: 2.75%–2.99%, P2O5: 0.91%–1.91%, ZrO2: 4.20%–4.85%, Na2O: 1.85%–3.20%, B2O3: 0–1.00%, and Li2O: 25.32%–26.52%.

[0127] Furthermore, in the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O], B2O3 [B2O3], and ZrO2 [ZrO2] satisfy the following relationship:

[0128] Z = -1.344 × (2.65 - 100 × [Na2O])2 + 0.466 × 100 × [B2O3] + 1.203 × 100 × [ZrO2], 4.80 ≤ Z ≤ 5.35, preferably 4.98 ≤ Z ≤ 5.20.

[0129] Lithium disilicate (Li2Si2O5) is an orthorhombic crystal based on a [Si2O5] tetrahedral array, with a flat or plate-like shape. Inside the glass-ceramic, the lithium disilicate crystal has a randomly oriented, interlocking microstructure, forcing cracks to distort their path as they pass through the crystal, thus preventing crack propagation and improving the strength and fracture toughness of the glass-ceramic. Simultaneously, the refractive index of lithium disilicate is close to that of the glass matrix (e.g., the substrate glass used to prepare the glass-ceramic in this application), making it an ideal crystal phase for preparing highly transparent glass-ceramics. In this application, the glass-ceramic contains a structure with lithium disilicate as the main crystal phase, which helps ensure high intrinsic strength and excellent optical properties.

[0130] In this application, by making the glass-ceramic meet specific composition and crystal phase structure, and by making the content and ratio of each component of the glass-ceramic meet specific ranges, and by making Na2O, B2O3, ZrO2 or Li2O meet specific molar percentage relationships, and by making the glass-ceramic meet the requirement that lithium disilicate is the main crystal phase, not only can the glass-ceramic be endowed with excellent optical properties and high intrinsic strength, but it can also enable the glass-ceramic to be rapidly and efficiently produced under conventional chemical strengthening process conditions, resulting in chemically strengthened glass-ceramics with high stress levels and high mechanical strength properties, thereby effectively reducing the manufacturing cost of high-strength chemically strengthened glass-ceramics.

[0131] The microcrystalline glass of this application can be obtained by heat treatment of a substrate glass. The composition of the substrate glass is the same as or substantially the same as that of the microcrystalline glass in terms of the molar percentage of oxides.

[0132] In this application, SiO2 is an essential component for forming the glass network structure and one of the main components for forming lithium disilicate crystals. The higher the SiO2 content in the glass system, the denser the network structure of the glass phase, and correspondingly, the higher the mechanical strength, the lower the coefficient of thermal expansion, and the better the heat resistance, dielectric properties, and chemical stability of the glass-ceramic. However, excessive SiO2 content will result in a higher melting temperature and greater melt viscosity of the substrate glass, increasing the difficulty of forming the substrate glass. Therefore, to balance the formability and various excellent properties of the glass, the molar percentage of SiO2 in the substrate glass or glass-ceramic in this application is 61.50% to 63.40%, preferably 61.50% to 63.30%, and more preferably 62.00% to 62.60%.

[0133] In some embodiments of this application, the SiO2 content in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 62.87%, 62.88%, 63.25%, 63.26%, 62.38%, 62.27%, 62.44%, 62.45%, 62.22%, 63.17%, 61.50%, 61.60%, 61.70%, 61.80%, 61.90%, or 62.00%. The values ​​can be 62.10%, 62.20%, 62.30%, 62.40%, 62.50%, 62.60%, 62.70%, 62.80%, 62.90%, 63.00%, 63.10%, 63.20%, 63.30%, or 63.40%, or any value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0134] In this application, Al2O3 is a component that forms the glass network structure. An appropriate amount of Al2O3 is beneficial for improving the chemical strengthening effect of glass-ceramics and, to some extent, promotes ion exchange during the chemical strengthening process. However, excessive Al2O3 will increase the glass viscosity and easily lead to the precipitation of other crystalline phases, such as petalite, affecting the crystalline structure of the glass-ceramics. Therefore, in order to obtain the desired crystalline structure and improve the chemical strengthening effect of the glass-ceramics, the molar percentage of Al2O3 in the substrate glass or glass-ceramics in this application is 2.75% to 2.99%.

[0135] In some embodiments of this application, the Al2O3 content in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 2.75%, 2.77%, 2.79%, 2.81%, 2.83%, 2.85%, 2.86%, 2.87%, 2.89%, 2.91%, 2.93%, 2.94%, 2.95%, 2.97%, or 2.99%, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0136] In this application, P2O5 acts as a nucleating agent, promoting uniform nucleation in the glass. Insufficient or excessive P2O5 content leads to poor crystallization, affecting the optical properties of the obtained glass-ceramic and reducing its transparency. Therefore, to obtain the desired crystal structure and achieve excellent optical and mechanical strength properties, the molar percentage of P2O5 in the substrate glass or glass-ceramic is set at 0.91% to 1.91%, preferably 1.20% to 1.91%, and more preferably 1.30% to 1.60%.

[0137] In some embodiments of this application, the content of P2O5 in the substrate glass or microcrystalline glass, based on the molar percentage of oxides, can be 0.91%, 0.95%, 1.00%, 1.05%, 1.10%, 1.15%, 1.20%, 1.25%, 1.30%, 1.35%, 1.40%, 1.45%, 1.50%, 1.55%, 1.60%, 1.65%, 1.70%, 1.75%, 1.80%, 1.85%, 1.41%, 1.53%, 1.54%, or 1.91%, or can be a value within a range defined by any two of the above specific values ​​as endpoints, as long as the microcrystalline glass or chemically strengthened microcrystalline glass with the desired performance of this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass or chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0138] In this application, ZrO2 is an intermediate oxide in glass formation. An appropriate amount of ZrO2 can improve the chemical stability of glass-ceramics, increase their hardness, and enhance their scratch and drop resistance. Furthermore, due to the high cation charge and strong field of ZrO2, it has a significant accumulation effect on the glass structure and is commonly used as a nucleating agent in glass-ceramics. However, excessive ZrO2 content can lead to glass phase separation or is detrimental to obtaining glass-ceramics with excellent optical properties. Therefore, to obtain glass-ceramics with excellent optical properties and high mechanical strength, the molar percentage of ZrO2 in the substrate glass or glass-ceramics in this application is 4.20% to 4.85%, preferably 4.20% to 4.80%.

[0139] In some embodiments of this application, the ZrO2 content in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 4.20%, 4.35%, 4.40%, 4.45%, 4.50%, 4.55%, 4.60%, 4.65%, 4.70%, 4.75%, 4.74%, 4.84%, 4.33%, 4.34%, 4.85%, or 4.80%, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0140] In this application, Na₂O is a network exooxide. An appropriate amount of Na₂O can provide free oxygen, improve the viscosity of the glass, promote the melting and clarification of the glass melt, and regulate the chemical strengthening rate. However, excessive Na₂O not only reduces the crystallinity of the glass-ceramic but also affects its chemical strengthening effect. Therefore, to improve the formability of the substrate glass and the chemical strengthening effect of the glass-ceramic, the molar percentage of Na₂O in the substrate glass or glass-ceramic is set at 1.80% to 3.20%, preferably 1.85% to 3.05%, and more preferably 2.20% to 3.00%.

[0141] In some embodiments of this application, the Na₂O content in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 1.80%, 1.85%, 1.90%, 1.95%, 2.00%, 2.05%, 2.10%, 2.15%, 2.20%, 2.25%, 2.30%, 2.35%, 2.40%, 2.45%, 2.50%, 2.55%, or 2.60%. The percentages are 2.65%, 2.70%, 2.75%, 2.80%, 2.85%, 2.90%, 2.95%, 3.00%, 3.20%, 2.36%, 2.96%, 3.01%, 2.93%, or 3.05%, or any value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0142] In this application, B2O3 is used as a flux to reduce the high-temperature viscosity of the glass, alleviate the melting difficulties caused by ZrO2, and lower the sag temperature of the glass. However, excessive B2O3 can easily lead to a decrease in the transparency of the glass-ceramic. Therefore, in order to improve the formability of the substrate glass and obtain the desired performance of the glass-ceramic, the molar percentage of B2O3 in the substrate glass or the glass-ceramic is 0 to 1.00%, preferably 0 to 0.65%.

[0143] In some embodiments of this application, the content of B2O3 in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 0, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.65%, 0.70%, 0.80%, 0.90%, 1.00%, or 0.60%, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0144] In this application, Li₂O is an essential component for forming the main crystalline phase, lithium disilicate, and also a necessary component for providing lithium ions for ion exchange during the chemical strengthening process. An appropriate amount of Li₂O not only improves the viscosity of the glass, promotes the melting and clarification of the molten glass, but also helps ensure the acquisition of the desired lithium disilicate crystal content. Simultaneously, Li₂O can provide alkali metal lithium ions for ion exchange with large-radius ions (e.g., sodium ions) in the molten salt bath, which is a significant factor affecting the achievable stress level of chemically strengthened glass-ceramics. However, excessive Li₂O will degrade the optical properties of the glass-ceramics. Therefore, in order to improve the formability of the substrate glass, obtain the desired structure of the glass-ceramics, and simultaneously improve the chemical strengthening effect of the glass-ceramics, the molar percentage of Li₂O in the substrate glass or glass-ceramics in this application is 25.32% to 26.52%, preferably 25.52% to 26.52%, and more preferably 25.52% to 26.00%.

[0145] In some embodiments of this application, the Li₂O content in the substrate glass or glass-ceramic, based on the molar percentage of oxides, can be 25.32%, 25.52%, 25.60%, 25.65%, 25.70%, 25.75%, 25.80%, 25.85%, 25.90%, 25.95%, 26.00%, 26.05%, 26.10%, 26.15%, 26.20%, 26.25%, etc. The values ​​can be 26.30%, 26.35%, 26.40%, 26.45%, 25.62%, 25.82%, 25.69%, 25.36%, 25.77%, 25.87%, 25.79%, 26.03%, 25.74%, or 26.52%, or any value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0146] In this application, by adjusting and controlling the content range of each oxide component, and by adjusting and controlling the ratio between each oxide component, especially the molar percentage relationship between Na2O, B2O3, ZrO2, or Li2O, it is not only beneficial to ensure that the microcrystalline glass meets the desired crystal phase structure, but also beneficial to ensure that the microcrystalline glass obtains high intrinsic strength with excellent optical properties. Furthermore, it is beneficial to ensure that the obtained microcrystalline glass achieves better chemical strengthening effect, enabling the rapid and efficient production of chemically strengthened microcrystalline glass with high stress level and high mechanical strength under conventional chemical strengthening process conditions, thereby effectively reducing the manufacturing cost of high-strength chemically strengthened microcrystalline glass.

[0147] In some embodiments of this application, the molar percentage relationship Z between Na2O, B2O3, and ZrO2 in the composition of the substrate glass or glass-ceramic can be 4.80, 4.85, 4.90, 4.95, 4.98, 5.05, 5.06, 5.07, 5.08, 5.09, 5.10, 5.11, 5.12, 5.13, 5.14, 5.15, 5.16, 5.17, 5.18, 5.19, 5.35, 5.30, or 5.20, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0148] In some embodiments of this application, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] in the composition of the substrate glass or microcrystalline glass satisfy the following relationship: 0.90% ≤ [Na2O] - [B2O3] ≤ 3.10%, preferably 1.25% ≤ [Na2O] - [B2O3] ≤ 3.02%, and more preferably 2.00% ≤ [Na2O] - [B2O3] ≤ 3.00%.

[0149] In some embodiments, the molar percentage difference between Na₂O and B₂O₃ in the composition of the substrate glass or glass-ceramic, [Na₂O]-[B₂O₃], can be 0.90%, 1.00%, 1.20%, 1.25%, 1.26%, 1.35%, 1.45%, 1.55%, 1.65%, 1.75%, 1.85%, 1.95%, 2.00%, 2.05%, 2.15%, 2.25%, or 2.3%. The percentages can be 5%, 2.45%, 2.50%, 2.55%, 2.65%, 2.75%, 2.85%, 2.95%, 3.10%, 1.79%, 0.96%, 2.36%, 2.96%, 3.01%, 2.93%, 3.00%, or 3.02%, or any value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the microcrystalline glass or chemically strengthened microcrystalline glass is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the desired performance of the microcrystalline glass or chemically strengthened microcrystalline glass is obtained.

[0150] In some embodiments of this application, the molar percentages of Na2O [Na2O] and Li2O [Li2O] in the composition of the substrate glass or microcrystalline glass satisfy the following relationship: 8.55≤[Li2O] / [Na2O]≤13.85, preferably 8.55≤[Li2O] / [Na2O]≤11.50.

[0151] In some embodiments, the molar percentage ratio of Li₂O and Na₂O in the composition of the substrate glass or glass-ceramic, [Li₂O] / [Na₂O], can be 8.55, 9.00, 9.50, 10.00, 10.50, 10.55, 11.00, 11.50, 12.00, 12.50, 13.00, 13.50, 13.83, 10.93, 13.01, 10.92, 8.73, 8.61, 8.79, 8.83, or 13.85, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the desired performance of the glass-ceramic or chemically strengthened glass-ceramic is obtained.

[0152] In some embodiments of this application, the composition of the substrate glass or glass-ceramic may include other components in addition to the above-mentioned composition range, as long as it can produce glass-ceramic or chemically strengthened glass-ceramic with the properties required by this application. For example, in some embodiments, the composition of the substrate glass or glass-ceramic may further include, in terms of the molar percentage of oxides: CaO: 0.00 mol%-1.00 mol%, K2O: 0.00 mol%-1.00 mol%.

[0153] In this application, phrases such as "lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the glass-ceramic" or "lithium disilicate is the main crystalline phase" or similar expressions refer to the lithium disilicate crystalline phase accounting for more than 70% by weight of all crystalline phases in the glass-ceramic according to embodiments of this application. In some embodiments, the weight percentage of the lithium disilicate crystalline phase among all crystalline phases of the glass-ceramic is more than 70%, preferably more than 85%. For example, the weight percentage of the lithium disilicate phase in all crystalline phases of the glass-ceramic can be 70%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 96%, 97%, 98%, 100%, or 95%, or it can be a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0154] In some embodiments of this application, the crystallinity of the glass-ceramic is not less than 45%, preferably 45% to 85%, and more preferably 55% to 65%. Higher crystallinity is more beneficial for the glass-ceramic to achieve high impact resistance and high intrinsic strength. However, excessively high crystallinity not only affects the chemical strengthening effect of the glass-ceramic, prolonging the chemical strengthening time to obtain chemically strengthened glass-ceramics with high stress levels, but also affects the optical properties of the glass-ceramic. In this application, by achieving the desired crystallinity of the glass-ceramic, it is beneficial to ensure that the glass-ceramic possesses excellent optical properties while meeting good impact resistance and high intrinsic strength requirements, and simultaneously improves its chemical strengthening effect.

[0155] In some embodiments of this application, the crystallinity of the glass-ceramic can be 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85%, or it can be a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0156] In some embodiments of this application, non-limiting examples of other possible crystalline phases in the glass-ceramic include: a lithium feldspar crystalline phase, and / or, a lithium phosphate crystalline phase. In some embodiments, the glass-ceramic further comprises a lithium feldspar crystalline phase, preferably comprising ≤20% by weight of the glass-ceramic; more preferably, the lithium feldspar crystalline phase may comprise ≤15%, ≤10%, or ≤5% by weight of the glass-ceramic. In some embodiments, it is preferable that the lithium feldspar crystalline phase is not present. By controlling the precipitation of other crystalline phases, it is more conducive to ensuring the formation of the desired interlocking structure of lithium disilicate, thereby ensuring that the glass-ceramic obtains high mechanical strength, excellent optical properties, and excellent damage resistance.

[0157] In some embodiments of this application, the average grain size of the glass-ceramic is no more than 100 nm, preferably no more than 40 nm, and more preferably 15–30 nm. A suitable average grain size is beneficial for the glass-ceramic to possess both excellent optical properties and high intrinsic strength. However, if the average grain size is too high, the glass-ceramic is prone to devitrification, and the chemical strengthening effect will also be affected. In this application, by ensuring that the glass-ceramic meets an appropriate average grain size, it is beneficial to ensure that the glass-ceramic has excellent optical properties while meeting good impact resistance and high intrinsic strength, and at the same time, it is beneficial to improve its chemical strengthening effect.

[0158] In some embodiments, the average grain size of the glass-ceramic can be 100nm, 50nm, 40nm, 35nm, 30nm, 25nm, 20nm, 15nm, or 10nm, or it can be a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0159] In some embodiments of this application, the microcrystalline glass is transparent in the visible light wavelength range. Preferably, at a thickness of 0.70 mm, the transmittance of the microcrystalline glass for 550 nm wavelength light is ≥90.00%, and more preferably >90.40%. Microcrystalline glass that meets this transmittance requirement ensures good light transmission and transparency, making it suitable for use in displays where high display quality is required. Here, "visible light wavelength range" refers to light with wavelengths from 360 nm to 740 nm.

[0160] In some embodiments, at a thickness of 0.70 mm, the transmittance of the glass-ceramic for 550 nm wavelength light can be 90.00%, 90.10%, 90.20%, 90.30%, 90.40%, 90.50%, 91.00%, 90.52%, 90.70%, 90.64%, 90.85%, 90.74%, 90.63%, 90.51%, or 92.00%, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application is obtained.

[0161] In some embodiments of this application, the haze of the glass-ceramic is <0.30% at a thickness of 0.70 mm. Haze refers to the cloud-like or cloudy appearance of the interior or surface of the glass-ceramic due to light diffusion. The lower the haze, the better the transparency and display effect of the glass-ceramic. In some embodiments, the haze of the glass-ceramic at a thickness of 0.70 mm can be 0.25%, 0.20%, 0.15%, 0.10%, 0.05%, 0.21%, 0.14%, 0.12%, 0.14%, 0.16%, or 0.30%, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic or chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0162] In some embodiments of this application, at a thickness of 0.70 mm, the b-value of the microcrystalline glass is <0.70, preferably b-value ≤0.60. In this application, the b-value refers to the optical b-value measured under a D65 light source. This application uses a Konica Minolta CM-3600A in transmittance mode to test the b-value, and the result shows b(D65). The smaller the b-value, the better the display effect of the microcrystalline glass can be ensured. When the b-value is too large, the microcrystalline glass will exhibit undesirable colors, causing its display effect to fail to meet the application requirements of the display cover glass.

[0163] In some embodiments, at a thickness of 0.70 mm, the b-value of the glass-ceramic can be 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.48, 0.47, 0.52, 0.51, 0.54, or 0.20, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0164] The microcrystalline glass of this application has high transmittance, low haze, and low b-value, all of which indicate that the microcrystalline glass of this application has superior optical performance and good uniformity. It is transparent and can meet the application requirements of cover glass for electronic device displays.

[0165] In some embodiments of this application, the Young's modulus of the glass-ceramic is ≥100 GPa, preferably 105–112.50 GPa. By ensuring the Young's modulus of the glass-ceramic is not less than 100 GPa, this application helps to guarantee the high network structure strength of the glass-ceramic, reduces the stress relaxation effect generated during ion exchange, and mitigates the weakening effect of high temperature and long duration on deep stress in the composite compressive stress during ion exchange.

[0166] In some embodiments, the Young's modulus of the glass-ceramic can be 100 GPa, 105 GPa, 110 GPa, 106.32 GPa, 111.12 GPa, 110.82 GPa, 111.32 GPa, 110.91 GPa, 112.10 GPa, 111.87 GPa, or 112.50 GPa, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic or chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0167] In some embodiments of this application, the Vickers hardness of the microcrystalline glass is ≥640 kgf / mm². 2 Preferably, the Vickers hardness of the microcrystalline glass is 640–680 kgf / mm². 2 The Vickers hardness of this glass-ceramic falls within the aforementioned range, indicating that it possesses high hardness and high intrinsic strength, thereby ensuring its excellent mechanical properties. This facilitates the fabrication of chemically strengthened glass-ceramics with high mechanical strength and excellent damage resistance.

[0168] In some embodiments, the Vickers hardness of the microcrystalline glass can be 640 kgf / mm². 2 650kgf / mm 2 660kgf / mm 2 670kgf / mm 2 660.12 kgf / mm 2 654.02 kgf / mm 2 650.20 kgf / mm 2 652.31 kgf / mm 2 659.65 kgf / mm 2 651.70 kgf / mm 2 654.92 or 680 kgf / mm 2 The values ​​can be any values ​​within the range defined by any two of the above specific values ​​as endpoints, as long as they produce the microcrystalline glass or chemically strengthened microcrystalline glass with the performance required by this application. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as they produce the microcrystalline glass or chemically strengthened microcrystalline glass with the performance required by this application.

[0169] In some embodiments, the glass-ceramic includes planar glass-ceramic or curved glass-ceramic. Preferably, when the glass-ceramic is curved, it can be produced by 3D hot bending of a crystallized glass raw material with a crystallinity of not less than 5%. Without being limited by any theory, this application has discovered that using partially crystallized glass raw material for 3D hot bending allows the glass to continue crystallizing under heat while undergoing deformation, reaching the target crystallinity. This enables more precise control of the deformation after 3D hot bending, resulting in smaller tolerance fluctuations in the profile, more stable dimensions, and higher dimensional accuracy of the curved glass-ceramic after hot bending. Those skilled in the art can determine the crystallinity of the selected partially crystallized glass raw material based on the desired crystallinity of the curved glass-ceramic. For example, when the desired crystallinity of the curved glass-ceramic is approximately 60%, a partially crystallized glass raw material with a crystallinity of 50% can be selected for hot bending to obtain a curved glass-ceramic that meets the target crystallinity. In this application, the composition of the partially crystallized glass is the same as or substantially the same as that of the microcrystalline glass, based on the molar percentage of oxides.

[0170] In some embodiments, the thickness of the microcrystalline glass is 0.10–5.00 mm. Exemplarily, the thickness of the microcrystalline glass can be 0.10–2.00 mm, 0.20–1.00 mm, or 0.40–0.80 mm.

[0171] Having introduced the composition and microstructure of glass-ceramics, the preparation methods of glass-ceramics will now be described in detail.

[0172] In this application, the preparation process of the microcrystalline glass mainly includes: the preparation process of the substrate glass and the heat treatment process of the substrate glass.

[0173] In this application, the substrate glass can be prepared using existing forming methods, and this application has no limitations on this. For example, the forming method of the substrate glass may include, but is not limited to, float glass, overflow glass, calendering, or casting processes. For instance, by uniformly mixing the components according to the formula, melting and forming the substrate glass, and then cooling and annealing it, the substrate glass can be obtained.

[0174] For example, raw materials (common industrial raw materials) are prepared according to the formula ratio, a clarifying agent is added, and then mixed for a period of time to obtain a uniformly mixed raw material mixture. The raw material mixture is placed in a platinum crucible and heated to 1250℃~1680℃, preferably a melting temperature of 1480℃~1680℃, and preferably held at this temperature for 3~12 hours. Then, it is poured into a molding die for cooling and shaping, preferably cooled to 750℃~1000℃, and then placed in an annealing furnace for annealing treatment, preferably at an annealing temperature of 400℃~650℃, and preferably for an annealing time of 10~48 hours. Afterward, it is cooled to room temperature in the furnace to obtain the substrate glass. Those skilled in the art can select the type and amount of clarifying agent according to their needs without any creative effort. Furthermore, the clarifying agent may include, but is not limited to, one or more of sodium chloride, tin oxide, antimony oxide, or arsenic oxide, and the amount of clarifying agent added may be 0-1wt% of the total amount of each raw material.

[0175] In some embodiments of this application, the heat treatment process of the substrate glass may include nucleation and / or crystallization, preferably both nucleation and crystallization. In some embodiments, the crystallization process includes a one-step crystallization or a two-step crystallization. In some embodiments, to prepare curved microcrystalline glass, a two-step crystallization process may be used. When a two-step crystallization process is used, the second crystallization step involves heating the crystallized glass material obtained from the first crystallization step to the crystallization temperature and performing a 3D hot bending process.

[0176] In some embodiments of this application, in order to obtain the desired physicochemical properties of the glass-ceramic, the heat treatment of the substrate glass can be performed in one step, or in two or more steps. A one-step heat treatment means that nucleation (i.e., nucleation treatment) is not performed separately; nucleation and target crystal growth are carried out directly in a single heating process, which can be understood as direct crystallization treatment. A two-step heat treatment means that two heating processes are performed: first, nucleation treatment, i.e., nucleation treatment, and then target crystal growth treatment, i.e., crystallization treatment.

[0177] To precipitate the desired crystalline phase and obtain the desired physicochemical properties in the glass-ceramic, the nucleation treatment temperature can be 530–600°C, and the nucleation treatment time can be 0–24 h, preferably 2–8 h; the crystallization treatment temperature can be 700–750°C, and the crystallization treatment time can be 0.10–24 h, preferably 1–3 h. During heat treatment, the heating rate is preferably controlled at 5–15°C / min, more preferably at 10°C / min. Here, the nucleation treatment temperature refers to the temperature at which crystal nuclei can form. The crystallization treatment temperature refers to the temperature at which the target crystal can grow in a controllable manner.

[0178] After heat treatment, those skilled in the art can also perform other conventional steps to obtain microcrystalline glass samples that meet the required specifications or requirements, such as shaping, cutting (e.g., cutting with a multi-wire cutting machine), CNC machining (computer numerical control), thinning, or polishing.

[0179] In some embodiments of this application, a chemically strengthened glass crystal is also provided, which is obtained by chemically strengthening the aforementioned glass crystal. The composition at the center of the chemically strengthened glass crystal is the same as that of the glass crystal described in any of the aforementioned embodiments. The chemically strengthened glass crystal includes a compressive stress layer region extending from the surface of the chemically strengthened glass crystal to the compression depth, and has tensile stress inside the chemically strengthened glass crystal.

[0180] Chemical strengthening treatment, also known as ion exchange, involves immersing glass-ceramics in a molten salt bath. This allows alkali metal ions with smaller ionic radii in the glass-ceramics to exchange with alkali metal ions with larger ionic radii in the molten salt bath, thereby forming a compressive stress layer on the surface of the glass-ceramics and resulting in chemically strengthened glass-ceramics with superior mechanical properties.

[0181] It should be understood that the surface composition of a glass-ceramic product after chemical strengthening may differ from that before the ion exchange process, compared to the glass-ceramic before chemical strengthening. This is because, during ion exchange, a certain type of alkali metal ion (e.g., Li) is present on the surface of the newly formed glass-ceramic. + Or Na + They will be respectively affected by larger alkali metal ions (e.g., Na+). + or K +However, in the embodiments, the glass composition and phase composition at or near the depth center of the glass-ceramic article will still have the composition and phase composition of the newly formed glass-ceramic. That is to say, in this application, the composition (e.g., the composition of the tensile stress layer) and phase composition at the center of the chemically strengthened glass-ceramic that has undergone chemical strengthening treatment are the same as or substantially the same as those of the newly formed glass-ceramic.

[0182] In some embodiments of this application, the chemical enhancement treatment can be performed using a single-step or multi-step enhancement method. The molten salt bath used for chemical enhancement treatment is a molten salt bath containing sodium and / or potassium salts. Preferably, the molten salt bath used for chemical enhancement in this application is a mixed molten salt bath containing sodium and potassium salts, and the temperature of the molten salt bath is preferably 380℃~470℃, more preferably 430℃~460℃. In some embodiments of this application, the concentration of potassium salt in the salt bath is preferably 0wt%~90wt%, and the concentration of sodium salt is preferably 10wt%~100wt%, more preferably a certain amount (e.g., 0-0.2wt%) of lithium salt is added to the salt bath. In some embodiments of this application, the chemical enhancement treatment time is preferably 0.1~3h. The sodium salt can be selected from at least one of sodium nitrate, sodium sulfate, and sodium carbonate, preferably sodium nitrate; the potassium salt can be selected from at least one of potassium nitrate, potassium sulfate, and potassium carbonate, preferably potassium nitrate; the lithium salt can be selected from at least one of lithium nitrate, lithium sulfate, and lithium carbonate, preferably lithium nitrate.

[0183] In some embodiments of this application, the chemically strengthened glass-ceramic comprises a lithium disilicate crystalline phase, wherein the lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the chemically strengthened glass-ceramic; the composition at the center of the chemically strengthened glass-ceramic, based on the molar percentage of oxides, includes: SiO2: 61.50%–63.40%, Al2O3: 2.75%–2.99%, P2O5: 0.91%–1.91%, ZrO2: 4.20%–4.85%, Na2O: 1.80%–3.20%, B2O3: 0–1.00%, and Li2O: 25.32%–26.52%.

[0184] Furthermore, in the composition at the center of the chemically strengthened glass crystal, the molar percentages of Na2O [Na2O], B2O3 [B2O3], and ZrO2 [ZrO2] satisfy the following relationship:

[0185] Z = -1.344 × (2.65 - 100 × [Na2O])2 + 0.466 × 100 × [B2O3] + 1.203 × 100 × [ZrO2], 4.80 ≤ Z ≤ 5.35, preferably 4.98 ≤ Z ≤ 5.20.

[0186] In some embodiments of this application, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] at the center of the chemically strengthened glass crystal satisfy the following relationship:

[0187] 0.90% ≤ [Na₂O] - [B₂O₃] ≤ 3.10%, preferably 1.25% ≤ [Na₂O] - [B₂O₃] ≤ 3.02%, more preferably 2.00% ≤ [Na₂O] - [B₂O₃] ≤ 3.00%; and / or,

[0188] In the composition at the center of the chemically strengthened glass crystal, the molar percentages of Na₂O [Na₂O] and Li₂O [Li₂O] satisfy the following relationship:

[0189] 8.55≤[Li2O] / [Na2O]≤13.85, preferably 8.55≤[Li2O] / [Na2O]≤11.50.

[0190] In some embodiments of this application, the chemically strengthened glass-ceramic has a tensile stress linear density (CT_LD) of 45,000–55,000 MPa / mm², where CT_LD is the tensile stress linear density. Preferably, the chemically strengthened glass-ceramic has a CT_LD of 48,000–53,000 MPa / mm². Controlling the CT_LD of the chemically strengthened glass-ceramic to be 45,000–55,000 MPa / mm² helps ensure that the tensile stress stored inside the chemically strengthened glass-ceramic is sufficiently concentrated, thereby ensuring that it has a high surface stress level and excellent damage resistance, such as excellent drop resistance, to meet market demands.

[0191] In some embodiments, the CT_LD of the chemically strengthened glass-ceramic can be 45000MPa / mm, 46000MPa / mm, 47000MPa / mm, 48000MPa / mm, 49000MPa / mm, 50000MPa / mm, 51000MPa / mm, 52000MPa / mm, 53000MPa / mm, 54000MPa / mm, 50479MPa / mm, 50547MPa / mm, 50297MPa / mm, 50497MPa / mm, 50833MPa / mm, 52768MPa / mm, or 55000MPa / mm, or a value within the range of any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that, in specific implementations, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0192] In some embodiments of this application, the chemically strengthened glass-ceramic has a CS_50 of 150–199 MPa, preferably 160–199 MPa. CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic. When a blunt or sharp object comes into contact with the chemically strengthened glass-ceramic, the stress structure on the surface of the chemically strengthened glass-ceramic preferentially offsets the impact force it receives. By giving the chemically strengthened glass-ceramic a higher surface stress level, it can offset more residual energy from drops, compression, impacts, or collisions, thereby helping to ensure its excellent damage resistance, such as excellent drop resistance.

[0193] In some embodiments, the CS_50 of the chemically strengthened glass-ceramic can be 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 163.97 MPa, 173.80 MPa, 168.90 MPa, 174.60 MPa, 178.20 MPa, 176.89 MPa, 179.72 MPa, or 199 MPa, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0194] In some embodiments of this application, the chemically strengthened glass-ceramic has a |CT_AV| of 80–98 MPa. |CT_AV| refers to the absolute value of the average tensile stress in the tensile stress layer. By setting the |CT_AV| of the chemically strengthened glass-ceramic to 80–98 MPa, it is beneficial to ensure that the chemically strengthened glass-ceramic has a better tensile stress layer distribution structure, resulting in a higher surface stress level. A higher surface compressive stress level can offset more residual energy from drops, compression, impacts, or collisions, thereby ensuring that the chemically strengthened glass-ceramic has excellent damage resistance.

[0195] In some embodiments, the |CT_AV| of the chemically strengthened glass-ceramic can be 80 MPa, 85 MPa, 90 MPa, 95 MPa, 96.94 MPa, 86.77 MPa, 89.37 MPa, 90.20 MPa, 92.10 MPa, 91.58 MPa, 93.60 MPa, or 98 MPa, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0196] In some embodiments of this application, the chemically strengthened glass-ceramic has a |CT_CV| of 115–142 MPa. |CT_CV| refers to the absolute value of the maximum tensile stress. Preferably, the chemically strengthened glass-ceramic has a |CT_CV| of 120–140 MPa. By ensuring that the |CT_CV| of the chemically strengthened glass-ceramic is 115–142 MPa, it is beneficial to ensure that the chemically strengthened glass-ceramic has a high level of surface stress. A higher level of surface compressive stress can offset more residual energy from drops, compression, impacts, or collisions, thereby ensuring that the chemically strengthened glass-ceramic has excellent damage resistance.

[0197] In some embodiments, the |CT_CV| of the chemically strengthened glass-ceramic can be 115 MPa, 120 MPa, 125 MPa, 130 MPa, 135 MPa, 125.68 MPa, 133.49 MPa, 136.28 MPa, 141.54 MPa, 141.63 MPa, 138.76 MPa, or 142 MPa, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0198] In some embodiments of this application, the Vickers hardness of the chemically strengthened glass-ceramic is ≥680 kgf / mm². 2 Preferably, the Vickers hardness of the chemically strengthened microcrystalline glass is 700 kgf / mm. 2 ~800kgf / mm 2 By ensuring that the Vickers hardness of chemically strengthened glass-ceramics is within the aforementioned range, high hardness and high mechanical strength can be imparted to the glass-ceramics, thereby ensuring their excellent resistance to damage.

[0199] In some embodiments, the Vickers hardness of the chemically strengthened glass-ceramic can be 680 kgf / mm². 2 690kgf / mm 2 700kgf / mm 2 710kgf / mm 2 720kgf / mm 2 730kgf / mm 2 740kgf / mm 2 750kgf / mm 2 760kgf / mm 2 770kgf / mm 2 780kgf / mm2 790kgf / mm 2 726.25 kgf / mm 2 723.96 kgf / mm 2 724.50 kgf / mm 2 720.31 kgf / mm 2 730.98 kgf / mm 2 718.60 kgf / mm 2 731.57 kgf / mm 2 Or 800 kgf / mm 2 The values ​​can be any values ​​within the range defined by any two of the above specific values ​​as endpoints, as long as they result in a chemically strengthened glass-ceramic with the performance required by this application. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as a chemically strengthened glass-ceramic with the performance required by this application is obtained.

[0200] In some embodiments of this application, the chemically strengthened glass-ceramic has a DOL_0 of 0.18t to 0.25t, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic. Preferably, the chemically strengthened glass-ceramic has a DOL_0 of 0.20t to 0.25t. By making the chemically strengthened glass-ceramic have...

[0201] A suitable DOL_0 can prevent sudden cracks from penetrating the compressive stress area and reaching the tensile stress area when blunt or sharp objects impact or pierce the glass, thus preventing the glass from shattering. This is more conducive to improving the ability of chemically strengthened glass to counteract the energy that drives crack propagation, thereby ensuring that chemically strengthened glass has excellent damage resistance, such as excellent drop resistance.

[0202] In some embodiments, the DOL_0 of the chemically strengthened glass-ceramic can be 0.18t, 0.20t, 0.22t, 0.23t, 0.24t, or 0.25t, or a value within a range defined by any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. For example, when the thickness of the chemically strengthened glass-ceramic is 0.7 mm, the DOL_0 of the chemically strengthened glass-ceramic can be 152.94 μm, 142.25 μm, 143.26 μm, 144.20 μm, 143.80 μm, 142.67 μm, 144.26 μm, 126 μm, 130 μm, 135 μm, 140 μm, 150 μm or 160 μm, or a value within the range of any two of the above specific values ​​as endpoints, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0203] In this application, by making the chemically strengthened glass crystal meet specific stress characteristics, it is possible to ensure that the chemically strengthened glass crystal has excellent mechanical strength properties, excellent mechanical strength properties, and excellent damage resistance properties, especially excellent drop damage resistance properties.

[0204] In some embodiments of this application, 80-grit sandpaper was used to conduct a sandpaper drop test on the chemically strengthened microcrystalline glass with a thickness of 0.7 mm. The average sandpaper drop height resisted by the chemically strengthened microcrystalline glass was ≥1.0 m, preferably ≥1.2 m, and more preferably ≥1.5 m. This indicates that the chemically strengthened microcrystalline glass of this application has excellent drop resistance. In some embodiments, 80-grit sandpaper is used to conduct a sandpaper drop test on the chemically strengthened microcrystalline glass with a thickness of 0.7 mm. The average sandpaper drop resistance height of the chemically strengthened microcrystalline glass can be 1.0m, 1.1m, 1.2m, 1.3m, 1.4m, 1.5m, 1.6m, 1.7m, 1.8m, 1.9m, 2.0m, 1.75m, 1.68m, 1.64m, 1.57m, 1.60m, 1.62m, 1.78m, or 2.1m, etc.

[0205] The high-performance microcrystalline glass or chemically strengthened microcrystalline glass provided in this application can be used in electronic devices, including but not limited to mobile phones, tablets, handheld game consoles, portable digital devices (e.g., digital cameras), vehicle central control systems, electronic whiteboard glass, smart home devices, and smart wearables (e.g., smart bracelets, smartwatches, smart glasses). It can also be used in vehicles, aircraft, or spacecraft, and in any glass device requiring microcrystalline glass. For example, it can be used for displays, cover glass, touchscreens, inner glass screens, or inner frames of electronic devices; for example, it can be used for windshields of vehicles, aircraft, or spacecraft, such as front windshields or side windshields. For example, it can be used for worktops, other surfaces, appliance doors, floor tiles, wall panels, or storage containers. Other surfaces can include, but are not limited to, exterior wall surfaces, stair tread surfaces, column cladding, or countertop surfaces; storage containers can include, but are not limited to, cups, plates, medicine bottles, or beverage bottles.

[0206] For example, the high-performance microcrystalline glass or chemically strengthened microcrystalline glass provided in this application can be used to manufacture glass devices. The glass devices referred to herein can be regular or irregular, and can be manufactured by those skilled in the art according to their needs.

[0207] For example, the high-performance microcrystalline glass or chemically strengthened microcrystalline glass provided in this application can be used to manufacture cover glass, which can be a display screen cover, back cover, or camera protective cover for electronic devices. For example, the high-performance microcrystalline glass or chemically strengthened microcrystalline glass provided in this application can be used in electronic devices. Reference Figure 9 , Figure 10 and Figure 11 This application provides an electronic device, which can be a mobile phone, tablet computer, smart wearable device, or other electronic products. The electronic device includes a housing 1 assembled on the outside of the electronic device, and components such as circuit boards and batteries located inside the housing 1. The housing 1 includes a display screen cover 11 assembled on the front side and a rear cover 12 assembled on the rear side. The display screen cover 11 covers the display module 4. The display screen cover 11 and / or the rear cover 12 are made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass. In this application embodiment, the display screen cover 11 and the rear cover 12 may be entirely made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass, or only partially made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass. In this application embodiment, the display screen may be a touch display screen, and the display screen cover 11 may be a protective cover disposed on the touch display screen. In this application embodiment, the rear cover 12 may only cover the rear side of the electronic device (and the side away from the display screen), or it may cover both the rear side and the side frame of the electronic device. Optionally, the rear cover 12 may cover all the side frames around the electronic device, or it may cover only part of the side frames.

[0208] In some embodiments of this application, such as Figure 10 As shown, the electronic device also includes a camera assembly 2 located inside the housing 1. The housing 1 may include a camera protective cover 13, which covers the camera assembly 2 to protect it. The camera protective cover 13 is made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass. In this embodiment, the camera protective cover 13 may be partially or entirely made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass. In this embodiment, the location of the camera protective cover 13 depends on the location of the camera assembly 2; it may be located on the front side of the electronic device or on the rear side. In some embodiments of this application, the camera protective cover 13 may be a separate structure from the display screen cover 11 or the rear cover 12. In other embodiments of this application, the camera protective cover 13 may be an integral structure with the display screen cover 11 or the rear cover 12.

[0209] In some embodiments of this application, such as Figure 11 As shown, the electronic device also includes a mid-frame 3 located between the display module 4 and the housing 1, the mid-frame 3 may include the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass.

[0210] In the embodiments of this application, the display screen cover, back cover, camera protective cover, and mid-frame of the electronic device may be made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass, or any two of them may be made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass, or all three of them may be made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass, or all four of them may be made of the aforementioned microcrystalline glass or chemically strengthened microcrystalline glass.

[0211] Those skilled in the art can select the thickness of the microcrystalline glass or chemically strengthened microcrystalline glass according to their needs. For example, the thickness of the microcrystalline glass or chemically strengthened microcrystalline glass can be 0.1-5 mm, 0.1-2.0 mm, 0.2-1 mm or 0.4-0.8 mm.

[0212] The technical solutions of this application will be further described in detail below with reference to the embodiments. The embodiments of this application described in detail below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0213] Example 1

[0214] (1) Preparation of substrate glass:

[0215] Prepare the raw materials (conventional industrial raw materials) according to the specified proportions. The total mass of the prepared raw materials is 1000g. Add 5g of clarifying agent sodium chloride (NaCl) to the prepared raw materials and mix them for 30 minutes using a V-type mixer to obtain a uniformly mixed raw material mixture.

[0216] The raw material mixture is transferred to a platinum crucible and melted in the platinum crucible at 1650°C for 5 hours. Then it is poured into a molding mold and cooled to 900°C. After that, it is placed in an annealing furnace at 500°C for 24 hours and then cooled to room temperature in the furnace to obtain the base glass brick.

[0217] (2) Preparation of microcrystalline glass: The substrate glass brick was placed in an annealing furnace and heated from room temperature to 550°C at a rate of 10°C / min for nucleation treatment. After holding at this temperature for 4 hours, the temperature was increased to 710°C at a rate of 10°C / min for crystallization treatment. After holding at this temperature for 1.5 hours, the temperature was lowered to room temperature at a rate of 1°C / min to obtain the microcrystalline glass sample brick. The composition of the prepared microcrystalline glass was the same as that of the substrate glass in terms of the molar percentage of oxides, as detailed in Table 1.

[0218] The obtained microcrystalline glass sample bricks are sequentially cut, CNC machined (the CNC instrument used in this application is model RCG500S), and polished under cold working conditions to obtain microcrystalline glass samples that meet the required specifications and requirements. In this application, the microcrystalline glass sample bricks are subjected to the aforementioned cold working treatment to produce microcrystalline glass samples with a thickness of 0.70 mm, specifically, to produce microcrystalline glass polished sheet samples of 50 mm × 50 mm × 0.70 mm.

[0219] The following tests were conducted on the microcrystalline glass sample obtained in Example 1:

[0220] The crystal phase composition, crystallinity, average grain size, Vickers hardness, Young's modulus of the microcrystalline glass samples, as well as the optical b-value, haze, and transmittance (under 550 nm wavelength light) of the microcrystalline glass sample with a thickness of 0.7 mm were tested respectively, and the results are shown in Table 2.

[0221] (3) Preparation of chemically strengthened glass-ceramics: The obtained glass-ceramic sample was placed in the strengthening furnace cavity and preheated for 5 minutes. After preheating, it was quickly placed in a molten salt bath at 460°C for chemical strengthening treatment. The composition of the molten salt was 70wt% KNO3 + 30wt% NaNO3 + 0.03wt% LiNO3 (based on the total mass of KNO3 and NaNO3, 0.03wt% LiNO3 was added). After chemical strengthening treatment for 2 hours, the glass-ceramic sample was taken out and placed on the furnace body of the strengthening furnace to be slowly cooled to room temperature. The salt coating on the surface of the glass-ceramic was washed off with water. After drying the glass-ceramic sample, the chemically strengthened glass-ceramics were obtained.

[0222] The following tests were conducted on the chemically strengthened glass-ceramic obtained in Example 1:

[0223] I. The chemically strengthened glass-ceramic was tested under an SLP 2000 (Luceo, Japan) stress meter (the light source wavelength was 518nm, SOC = 26 (nm / cm) / MPa, refractive index was set to 1.56, and exposure time was 300μsec) to measure |CT_CV|, DOL_0, CS_50 and |CT_AV|; then the tensile stress linear density (CT_LD) value was calculated, and the results are shown in Table 3.

[0224] II. The Vickers hardness of the chemically strengthened microcrystalline glass was tested, and the results are shown in Table 3.

[0225] III. The average drop height resistance of chemically strengthened microcrystalline glass to sandpaper was tested, and the results are shown in Table 3.

[0226] Examples 2-7

[0227] Each of these experiments was conducted with reference to Example 1, except that the raw material composition, different process parameters, and corresponding test results for each example are shown in Tables 1-3.

[0228] The XRD pattern of the microcrystalline glass in Example 2 is as follows: Figure 1 As shown in the figure, the main crystalline phase in the glass-ceramic is lithium disilicate.

[0229] The transmittance curve of the microcrystalline glass in Example 2 is shown in the figure below. Figure 2 As shown in the figure, microcrystalline glass is transparent in the visible light range and has high transmittance.

[0230] The XRD patterns of the glass-ceramic in Example 2 before and after chemical strengthening are shown in the figure below. Figure 3 As shown in the figure, the crystal phase structure of the glass-ceramic did not change significantly before and after the chemical strengthening treatment. The main crystal phase of the chemically strengthened microcrystals made from the glass-ceramic was also the lithium disilicate crystal phase.

[0231] The actual images of the microcrystalline glass in Examples 2 and 7 are shown below. Figure 4 , Figure 5 As shown, the image was taken on a piece of paper against a black background to demonstrate the state of the microcrystalline glass sheet. As can be seen from the image, the microcrystalline glass of this application, due to its small b-value, is essentially transparent and colorless, thus achieving a good display effect.

[0232] Comparative Examples 1-12

[0233] The experiments were conducted in accordance with Example 1, with the difference being that the raw material composition, different process parameters, and corresponding test results of each comparative example are shown in Tables 1-3.

[0234] The actual images of the glass-ceramics in Comparative Examples 5, 6, and 8 are shown below. Figure 6 , Figure 7 , Figure 8 As shown, the image was taken on a piece of paper against a black background to demonstrate the state of the microcrystalline glass sheet. The image reveals that the comparative microcrystalline glass exhibits a noticeable bluish tint due to its larger b-value. The larger the b-value, the more pronounced the blue tint, and the greater its impact on the display effect.

[0235]

[0236]

[0237]

[0238] As can be seen from the embodiments and comparative examples described in Tables 1-3 above, compared with the comparative examples, the embodiments of this application, by controlling the composition and ratio of each component of the glass-ceramic, while satisfying the content range of each oxide, control the molar percentage relationship between Na2O, B2O3, ZrO2 or Li2O to meet specific range requirements. At the same time, the glass-ceramic forms a microstructure with lithium disilicate as the main crystalline phase, which not only endows the glass-ceramic with excellent optical properties (e.g., high transmittance, low haze and low b-value) and high intrinsic strength (high Young's modulus and high Vickers hardness), but also ensures that the glass-ceramic can be rapidly and efficiently produced with high stress level and high mechanical strength under conventional chemical strengthening process conditions. The chemically strengthened glass-ceramic produced by the embodiments of this application has high CS_50, |CT_AV|, DOL_0 and CT_LD, and has excellent drop resistance.

[0239] In Comparative Examples 1-12, the glass formulations do not simultaneously satisfy the content ranges of each oxide in this application, nor the molar percentage relationships between Na2O, B2O3, ZrO2, or Li2O. Ultimately, in each comparative example, either the resulting microcrystalline glass exhibits poor optical properties (e.g., low transmittance, high optical b-value, or high haze), or, under the same chemical strengthening process conditions, the stress performance of the chemically strengthened microcrystalline glass is inferior to that of the exemplary embodiments, resulting in poorer drop resistance. In other words, because the comparative examples do not simultaneously meet the requirements of this application, they cannot simultaneously achieve both excellent optical performance and high stress levels.

[0240] The above are merely specific embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A microcrystalline glass, characterized in that, The glass-ceramic contains a lithium disilicate crystalline phase, wherein the lithium disilicate crystalline phase has a higher weight percentage than other crystalline phases present in the glass-ceramic. The microcrystalline glass comprises, by molar percentage of oxides: SiO2: 61.50%~63.40%, Al2O3: 2.75%~2.99%, P2O5: 0.91%~1.91%, ZrO2: 4.20%~4.85%, Na2O: 1.80%~3.20%, B2O3: 0~1.00%, and Li2O: 25.32%~26.52%. Furthermore, in the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O], B2O3 [B2O3], and ZrO2 [ZrO2] satisfy the following relationship: Z=-1.344×(2.65-100×[Na2O]) 2 +0.466×100×[B2O3]+1.203×100×[ZrO2],4.98≤Z≤5.35; At a thickness of 0.70 mm, the b-value of the microcrystalline glass is < 0.

70.

2. The microcrystalline glass according to claim 1, characterized in that, 4.98≤Z≤5.20。 3. The microcrystalline glass according to claim 1, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] satisfy the following relationship: 0.90%≤[Na2O]-[B2O3]≤3.10%.

4. The microcrystalline glass according to claim 3, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] satisfy the following relationship: 1.25%≤[Na2O]-[B2O3]≤3.02%.

5. The microcrystalline glass according to claim 3, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and B2O3 [B2O3] satisfy the following relationship: 2.00%≤[Na2O]-[B2O3]≤3.00%.

6. The microcrystalline glass according to claim 1, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and Li2O [Li2O] satisfy the following relationship: 8.55≤[Li2O] / [Na2O]≤13.

85.

7. The microcrystalline glass according to claim 6, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and Li2O [Li2O] satisfy the following relationship: 8.55≤[Li2O] / [Na2O]≤11.

50.

8. The microcrystalline glass according to claim 3, characterized in that, In the composition of the microcrystalline glass, the molar percentages of Na2O [Na2O] and Li2O [Li2O] satisfy the following relationship: 8.55≤[Li2O] / [Na2O]≤13.

85.

9. The microcrystalline glass according to any one of claims 1-8, characterized in that, Of all the crystal phases in the microcrystalline glass, the lithium disilicate crystal phase accounts for more than 70% by weight.

10. The microcrystalline glass according to claim 9, characterized in that, Of all the crystal phases in the microcrystalline glass, the lithium disilicate crystal phase accounts for more than 85% by weight.

11. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass contains, by molar percentage of oxides: The molar percentage of SiO2 is 61.50%~63.30%; and / or, The molar percentage of P2O5 is 1.20%~1.91%; and / or, The molar percentage of Na₂O is 1.85%~3.05%; and / or, The molar percentage of B2O3 is 0~0.65%; and / or, The molar percentage of ZrO2 is 4.20%~4.80%; and / or, The molar percentage of Li2O is 25.52%~26.52%.

12. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass contains, by molar percentage of oxides: The molar percentage of SiO2 is 62.00%~62.60%; and / or, The molar percentage of P2O5 is 1.30%~1.60%; and / or, The molar percentage of Na₂O is 2.20%~3.00%; and / or, The molar percentage of Li2O is 25.52%~26.00%.

13. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass contains, by molar percentage of oxides: The molar percentage of SiO2 is 62.88%, 63.30%, 62.50%, 63.26%, 62.38%, 62.27%, 62.45%, 62.22%, or 63.17%; and / or, The molar percentage of Al2O3 is 2.86%, 2.87%, 2.93%, 2.94%, or 2.99%; and / or, The molar percentage of P2O5 is 1.00%, 1.20%, 1.30%, 1.60%, 1.40%, 1.41%, 1.53%, or 1.54%; and / or, The molar percentage of ZrO2 is 4.80%, 4.74%, 4.84%, 4.33%, 4.34%, or 4.35%; and / or, The molar percentage of Na₂O is 1.85%, 2.35%, 1.95%, 2.36%, 2.96%, 3.01%, 2.93%, or 2.95%; and / or, The molar percentages of Li2O are 25.62%, 25.82%, 25.69%, 25.36%, 25.77%, 25.87%, 25.90%, 25.79%, 26.03%, or 25.74%.

14. The microcrystalline glass according to any one of claims 1-8, characterized in that, The composition of the glass-ceramic, expressed as a molar percentage of oxides, satisfies the following: The value of equation Z is 5.19, 5.10, 5.09, 5.06, or 5.13; and / or, The values ​​of [Na₂O]-[B₂O₃] are 1.26%, 1.79%, 0.96%, 2.36%, 2.96%, 3.01%, 2.93%, or 2.95%; and / or, The values ​​of [Li2O] / [Na2O] are 13.83, 10.93, 13.01, 10.92, 8.73, 8.61, 8.79 or 8.

83.

15. The microcrystalline glass according to any one of claims 1-8, characterized in that, The crystallinity of the microcrystalline glass is not less than 45%; and / or, In the microcrystalline glass, the average grain size does not exceed 100 nm.

16. The microcrystalline glass according to claim 15, characterized in that, The crystallinity of the microcrystalline glass is 45%~85%; and / or, In the microcrystalline glass, the average grain size does not exceed 40 nm.

17. The microcrystalline glass according to claim 15, characterized in that, The crystallinity of the microcrystalline glass is 55%~65%; and / or, The average grain size in the microcrystalline glass is 15~30nm.

18. The microcrystalline glass according to claim 9, characterized in that, The crystallinity of the microcrystalline glass is not less than 45%; and / or, The average grain size in the microcrystalline glass does not exceed 100 nm.

19. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass is transparent in the visible light wavelength range; and / or, At a thickness of 0.7 mm, the haze of the microcrystalline glass is <0.30%.

20. The microcrystalline glass according to claim 19, characterized in that, At a thickness of 0.70 mm, the transmittance of the microcrystalline glass for 550 nm wavelength light is ≥90.00%.

21. The microcrystalline glass according to claim 19, characterized in that, At a thickness of 0.70 mm, the transmittance of the microcrystalline glass for 550 nm wavelength light is >90.40%.

22. The microcrystalline glass according to claim 15, characterized in that, The microcrystalline glass is transparent in the visible light wavelength range; and / or, At a thickness of 0.7 mm, the haze of the microcrystalline glass is <0.30%.

23. The microcrystalline glass according to any one of claims 1-8, characterized in that, At a thickness of 0.70 mm, the b-value of the microcrystalline glass is ≤0.

60.

24. The microcrystalline glass according to any one of claims 1-8, characterized in that, The Young's modulus of the microcrystalline glass is ≥100 GPa; and / or, The Vickers hardness of the microcrystalline glass is ≥640 kgf / mm². 2 .

25. The microcrystalline glass according to claim 24, characterized in that, The Young's modulus of the microcrystalline glass is 105~112.50 GPa; and / or, The Vickers hardness of the microcrystalline glass is 640~680 kgf / mm. 2 .

26. The microcrystalline glass according to claim 15, characterized in that, The Young's modulus of the microcrystalline glass is ≥100 GPa; and / or, The Vickers hardness of the microcrystalline glass is ≥640 kgf / mm². 2 .

27. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass includes planar microcrystalline glass or curved microcrystalline glass.

28. The microcrystalline glass according to claim 27, characterized in that, When the microcrystalline glass is a curved microcrystalline glass, the microcrystalline glass is made by 3D hot bending forming of crystallized glass raw material with a crystallinity of not less than 5%.

29. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass is made from a substrate glass through heat treatment.

30. The microcrystalline glass according to claim 29, characterized in that, The heat treatment process includes nucleation and / or crystallization.

31. The microcrystalline glass according to claim 30, characterized in that, The crystallization process includes a one-step crystallization process or a two-step crystallization process.

32. The microcrystalline glass according to claim 28, characterized in that, Curved microcrystalline glass is prepared by a two-step crystallization process. When the two-step crystallization process is used, the second crystallization process is to heat the crystallized glass raw material obtained from the first crystallization process to the crystallization temperature and perform 3D hot bending forming.

33. A chemically strengthened microcrystalline glass, characterized in that, The chemically strengthened glass-ceramic is obtained by chemically strengthening the glass-ceramic of any one of claims 1-32, wherein the composition of the center or tensile stress layer of the chemically strengthened glass-ceramic is the same as that of the glass-ceramic, the chemically strengthened glass-ceramic includes a compressive stress layer region extending from the surface of the chemically strengthened glass-ceramic to the compression depth, and has tensile stress inside the chemically strengthened glass-ceramic.

34. The chemically strengthened microcrystalline glass according to claim 33, characterized in that, The chemically strengthened microcrystalline glass has a CT_LD of 45000~55000 MPa / mm, where CT_LD is the tensile stress linear density; and / or, The chemically strengthened glass-ceramic has a DOL_0 of 0.18t~0.25t, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic; and / or, The chemically strengthened glass-ceramic has a CS_50 of 150~199MPa, where CS_50 refers to the compressive stress value at a depth of 50μm measured from the main surface of the chemically strengthened glass-ceramic; and / or, The chemically strengthened microcrystalline glass has a |CT_AV| of 80~98 MPa, where |CT_AV| is the absolute value of the average tensile stress; and / or, The chemically strengthened microcrystalline glass has a |CT_CV| of 115~142 MPa, where |CT_CV| is the absolute value of the maximum tensile stress.

35. The chemically strengthened glass-ceramic according to claim 34, characterized in that, The chemically strengthened microcrystalline glass has a tensile stress linear density (CT_LD) of 48000~53000 MPa / mm²; and / or, The chemically strengthened glass-ceramic has a DOL_0 of 0.20t~0.25t, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic; and / or, The chemically strengthened glass-ceramic has a CS_50 of 160~199MPa, where CS_50 refers to the compressive stress value at a depth of 50μm measured from the main surface of the chemically strengthened glass-ceramic; and / or, The chemically strengthened microcrystalline glass has a |CT_CV| of 120~140MPa, where |CT_CV| is the absolute value of the maximum tensile stress.

36. The chemically strengthened microcrystalline glass according to any one of claims 33-35, characterized in that, The chemically strengthened microcrystalline glass has a Vickers hardness greater than or equal to 680 kgf / mm². 2 .

37. The chemically strengthened glass-ceramic according to claim 36, characterized in that, The Vickers hardness of the chemically strengthened microcrystalline glass is 700 kgf / mm. 2 ~800kgf / mm 2 .

38. The chemically strengthened microcrystalline glass according to claim 33, characterized in that, The molten salt bath used for the chemical enhancement treatment is a molten salt bath containing sodium and / or potassium salts, the temperature of which is 380℃~470℃, and the chemical enhancement treatment time is 0.1~3h.

39. The chemically strengthened microcrystalline glass according to claim 38, characterized in that, The molten salt bath for chemical strengthening is a mixed molten salt bath containing sodium and potassium salts. The concentration of potassium salt in the salt bath is 0wt% to 90wt%, the concentration of sodium salt is 10wt% to 100wt%, and 0-0.2wt% lithium salt is added to the salt bath.

40. The chemically strengthened microcrystalline glass according to claim 38 or 39, characterized in that, The temperature of the molten salt bath is 430℃~460℃.

41. The chemically strengthened microcrystalline glass according to claim 38 or 39, characterized in that, The molten salt bath consists of 70 wt% KNO3, 30 wt% NaNO3, and 0.03 wt% LiNO3, which accounts for the total mass of KNO3 and NaNO3.

42. A cover glass, characterized in that, The cover glass is made of microcrystalline glass as described in any one of claims 1-32 or chemically strengthened microcrystalline glass as described in any one of claims 33-41.

43. An electronic device, characterized in that, The electronic device comprises a microcrystalline glass as described in any one of claims 1-32 or a chemically strengthened microcrystalline glass as described in any one of claims 33-41.

44. The electronic device according to claim 43, characterized in that, The electronic device includes a housing assembled on the outside of the electronic device and a circuit board located inside the housing, the housing being made of microcrystalline glass as described in any one of claims 1-32 or chemically strengthened microcrystalline glass as described in any one of claims 33-41.

45. The electronic device according to claim 44, characterized in that, The housing includes a display cover assembled on the front side of the electronic device, the display cover comprising microcrystalline glass as claimed in any one of claims 1-32 or chemically strengthened microcrystalline glass as claimed in any one of claims 33-41.

46. ​​The electronic device according to claim 44, characterized in that, The housing includes a rear cover assembled on the rear side of the electronic device, the rear cover being made of microcrystalline glass as claimed in any one of claims 1-32 or chemically strengthened microcrystalline glass as claimed in any one of claims 33-41.

47. The electronic device according to claim 44, characterized in that, The electronic device further includes a camera assembly located inside the housing, the housing including a camera protective cover covering the camera assembly, the camera protective cover being made of microcrystalline glass as described in any one of claims 1-32 or chemically strengthened microcrystalline glass as described in any one of claims 33-41.

48. The electronic device according to claim 44, characterized in that, The electronic device further includes a mid-frame, the mid-frame comprising a microcrystalline glass as claimed in any one of claims 1-32 or a chemically strengthened microcrystalline glass as claimed in any one of claims 33-41.

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