Chemically strengthened microcrystalline glass as well as preparation method and application thereof

Abstract

The embodiment of the invention discloses chemically strengthened microcrystalline glass as well as a preparation method and application thereof. The chemically strengthened glass ceramic is provided with a Na / Li exchange layer and a compressive stress layer, and the depth of the compressive stress layer and the total thickness t of the chemically strengthened glass ceramic meet the following condition: 0.15 t to 0.22 t; and the compressive stress strength CS50 at the strengthening depth of 50 [mu] m on the surface layer of the chemically strengthened glass ceramic and the total thickness t of the chemically strengthened glass ceramic meet the following condition: 130 + (20t-13) * 15 MPa to 230 + (20t-13) * 15 MPa. Meanwhile, the CS50 and the depth of the pressure stress layer meet the condition that CS50 / (Doc-50) is equal to 1.4-6. The chemical reinforced glass ceramic is high in rough ground puncture resistance, and chemical reinforcement conditions of the preparation method are easy to control, so that the prepared chemical reinforced glass ceramic is stable in performance and high in efficiency, and the preparation cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of glass products, and specifically relates to a chemically strengthened microcrystalline glass and a preparation method and application thereof. Background Art

[0002] Glass is widely used in daily life due to its transparency and high temperature resistance. For example, glass is widely used in protective devices, decoration and other fields. However, glass also has certain shortcomings, such as weak impact resistance and fragility, which limits the application of glass in some fields.

[0003] With the popularity of electronic products, the requirements for glass materials are getting higher and higher. For example, the screen protection materials on smartphones are mostly chemically strengthened glass materials. And with the development of electronic products, the back cover materials of electronic products are gradually replaced by glass and other materials.

[0004] At present, the industry's cover glass materials are developing from aluminum-silicon glass to lithium-aluminum-silicon glass. With the improvement of chemical strengthening, the cover's ability to resist puncture on rough surfaces has been effectively improved. From 2016 to 2021, the industry's second-strength glass has been developing in the direction of improving deep stress, achieving a generation-by-generation improvement in sandpaper drop resistance.

[0005] However, in actual applications, it is found that the current aluminum-silicon glass in the industry, such as cover glass materials, has the following shortcomings:

[0006] The main body of the second-strength glass is lithium aluminum silicate glass, and the Young's modulus of lithium aluminum silicate glass is generally ~80GPa. The further improvement of its stress strength is limited by the compressive stress storage capacity of the matrix; excessive compressive stress introduces high internal tensile stress. If the tensile stress is too high, it will cause the glass failure fragments to be too small (<3mm) or the cover glass to explode. Therefore, the improvement of the strength of the second-strength glass is limited by the main body strength, and the improvement of the anti-drop performance is relatively limited.

[0007] Since 2020, the cover glass industry has introduced microcrystalline glass as a new development direction for cover glass. The nanocrystals inside the microcrystalline glass can resist crack penetration, and the compressive stress introduced by ion exchange can resist crack expansion. Through dual effects, the anti-drop ability of the cover glass is improved (see the mechanism for details). Figure 1 ). Therefore, the drop resistance on rough ground is qualitatively improved compared to the second-strength glass.

[0008] As disclosed in a glass-ceramic, its main crystal phases are spodumene and lithium disilicate; the water in its strengthening furnace needs to actively introduce Li2O to control the surface Na salt concentration, so as to reduce the degree of Na salt precipitation at 85° temperature / 85° humidity. This kind of crystal phase design uses K / Na and Na / Li secondary exchanges to achieve strength improvement. However, in the research, it is found that the characteristics of this glass-ceramic are that the crystallinity needs to be relatively high (≥85wt%) to ensure excellent optical properties of the raw materials (transmittance ≥89.5%, absolute value of chromatic aberration b ≤ 0.5, haze ≤ 0.15%). However, during the 3D hot bending process of this kind of glass-ceramic, the crystal phase is easily affected by heat, resulting in deterioration of optical properties; and the ion exchange of the glass-ceramic is affected by the crystal phase and requires a longer exchange path. Therefore, it is difficult to obtain a relatively high compressive stress during chemical strengthening, and the improvement of the anti-drop performance is still not ideal. Summary of the Invention

[0009] The purpose of this application is to overcome the deficiencies of the prior art, and provide a chemically strengthened glass-ceramic, its preparation method and its application, so as to solve the technical problems that the compressive stress of existing aluminosilicate glass and chemically strengthened glass-ceramic is difficult to further improve, and the anti-drop performance is not ideal.

[0010] To achieve the above application purpose, on the one hand, an embodiment of this application provides a chemically strengthened glass-ceramic. The chemically strengthened glass-ceramic of the embodiment of this application has a Na / Li exchange layer. The depth Doc of the compressive stress layer of the chemically strengthened glass-ceramic is 0.15t - 0.22t; the compressive stress intensity CS50 at the surface strengthening depth of 50μm of the chemically strengthened glass-ceramic is 130 + (20t - 13) × 15 MPa - 230 + (20t - 13) × 15 MPa; and CS50 and Doc satisfy: CS50 / (Doc - 50) is 1.4 - 6, with the unit of MPa / μm; where t is the total thickness of the chemically strengthened glass-ceramic.

[0011] The chemically strengthened glass-ceramic of the embodiment of this application has a specific compressive stress layer depth, compressive stress intensity, and the relationship between the compressive stress layer depth and the compressive stress intensity, endowing the chemically strengthened glass-ceramic with a relatively high compressive stress. The stress intensity is greatly improved compared with the current aluminosilicate glass and glass-ceramic, and can resist crack propagation. Therefore, the puncture resistance of the chemically strengthened glass-ceramic of the embodiment of this application to rough ground is significantly improved, and the drop height on rough ground is higher than that of the existing aluminosilicate glass and glass-ceramic.

[0012] Optionally, when squeezing the chemically strengthened glass-ceramic to break with a 10mm diameter round head metal pressure bar, the average size of the longest side of the fragments ≥ 5mm; and / or

[0013] When the thickness is 0.6mm, the sandpaper drop height of the chemically strengthened glass-ceramic ≥ 1.5m; and / or

[0014] When stored in an environment of 85°C temperature and 85% humidity for 72 hours, no sodium salt precipitation appears on the outer surface of the chemically strengthened glass-ceramics.

[0015] When the thickness of the chemically strengthened glass-ceramics is ≤ 0.8 mm, the average light transmittance at wavelengths of 400 - 940 nm is ≥ 89.5%, the single-point transmittance difference between 550 nm and 400 nm wavelengths is < 1%, the absolute value of the color coordinate b is ≤ 0.4, and the haze is ≤ 0.15%.

[0016] Based on the above-mentioned depth of the compressive stress layer, compressive stress intensity, and the relationship between the depth of the compressive stress layer and the compressive stress intensity of the chemically strengthened glass-ceramics, the chemically strengthened glass-ceramics not only have excellent puncture resistance to rough ground, but also have a high anti-drop height, good thermal and humidity stability, and good optical properties such as light transmittance.

[0017] Optionally, the main crystal phase of the parent glass-ceramics used to form the chemically strengthened glass-ceramics is any one of lithium silicate or β - quartz solid solution, and the total mass fraction of the crystal phases contained is 35 - 75%, and the total content of the secondary crystal phases is < 5%. By controlling the type of the main crystal phase and the crystal phase content of the parent glass-ceramics, it can effectively prevent the Na / Li exchange layer contained in the chemically strengthened glass-ceramics from being adversely affected by Li, and can effectively control the CS50 range, thereby further improving the puncture resistance of the chemically strengthened glass-ceramics to rough ground. At the same time, it can also improve the impact resistance of the chemically strengthened glass-ceramics and have high optical properties such as light transmittance.

[0018] Furthermore, the parent glass-ceramics include the main components and a nucleating agent; among them, the main components include SiO2, Al2O3, B2O3, Li2O, Na2O, and K2O, and satisfy: the content of SiO2 + Al2O3 + B2O3 is 58 - 85 mol%; the content of Li2O + Na2O + K2O is 10 - 32 mol%; the nucleating agent includes TiO2, P2O5, and ZrO2, and satisfy: the content of TiO2 + P2O5 + ZrO2 is 2 - 8 mol%. These components of the parent glass-ceramics endow the parent glass-ceramics and the chemically strengthened glass-ceramics with the above-mentioned type of the main crystal phase and crystal phase content, thereby improving the puncture resistance of the chemically strengthened glass-ceramics to rough ground and improving the optical properties such as light transmittance of the chemically strengthened glass-ceramics.

[0019] Furthermore, the parent glass-ceramics are prepared by the melting casting method or the rolling method.

[0020] Furthermore, the parent glass-ceramics are subjected to the following two-step heat treatment:

[0021] The first heat treatment: the temperature is 500 - 600°C, and the treatment time is 0.1 - 10 h;

[0022] Second heat treatment: the temperature is 640 - 800 °C, and the treatment time is 0.1 - 10 h.

[0023] By adopting the preparation method of the base glass-ceramics or further using the two-step heat treatment, the main crystal phase and its content required for the formation of the base glass-ceramics with the required crystallinity can be obtained, and the main crystal phase and crystal phase content can be adjusted, so as to improve the anti-piercing ability of the chemically strengthened glass-ceramics on rough ground and the optical performance.

[0024] Furthermore, the Young's modulus of the chemically strengthened glass-ceramics ≥ 95 GPa. Based on the types of main crystal phases and crystal phase content of the base glass-ceramics of the chemically strengthened glass-ceramics, the chemically strengthened glass-ceramics are given a high Young's modulus, thus endowing the chemically strengthened glass-ceramics with a larger storage space for compressive stress, providing conditions for the improvement of the compressive stress of the chemically strengthened glass-ceramics.

[0025] Optionally, the surface layer of the chemically strengthened glass-ceramics also has a K / Na exchange layer. By introducing the K / Na exchange layer (potassium layer), the impact resistance of the chemically strengthened glass-ceramics is further improved, and it is also helpful to maintain the anti-drop performance of the chemically strengthened glass-ceramics on rough ground.

[0026] Furthermore, the thickness of the K / Na exchange layer ≤ 3 μm. By controlling the thickness of the K / Na exchange layer (potassium layer), the impact resistance and anti-drop performance of the chemically strengthened glass-ceramics on rough ground can be further improved. And based on the depth of the compressive stress layer, the strength of the compressive stress, and the relationship between the depth of the compressive stress layer and the strength of the compressive stress, the thickness requirement of the K / Na exchange layer can be effectively reduced.

[0027] Optionally, the chemically strengthened glass-ceramics is any one of 2D-shaped strengthened glass-ceramics, 2.5D-shaped chemically strengthened glass-ceramics, and 3D-shaped chemically strengthened glass-ceramics. Due to the excellent anti-piercing ability and optical performance of the chemically strengthened glass-ceramics, it can be any one of 2D-shaped chemically strengthened glass-ceramics, 2.5D-shaped chemically strengthened glass-ceramics, and 3D-shaped chemically strengthened glass-ceramics, expanding the application range of the chemically strengthened glass-ceramics and improving the quality and performance stability of the corresponding products.

[0028] Furthermore, when the chemically strengthened glass-ceramics are 2D-shaped chemically strengthened glass-ceramics or / and 2.5D-shaped chemically strengthened glass-ceramics, the absolute value of the color coordinate b of the 2D-shaped chemically strengthened glass-ceramics or / and 2.5D-shaped chemically strengthened glass-ceramics ≤ 0.3, and the haze ≤ 0.14.

[0029] When the chemically strengthened glass-ceramics are 2D-shaped chemically strengthened glass-ceramics or 2.5D-shaped chemically strengthened glass-ceramics, they have excellent anti-piercing ability on rough ground and light transmittance.

[0030] Furthermore, the chemically strengthened glass-ceramics are 3D chemically strengthened glass-ceramics, and the bending angle of the long side is 15-89°; and / or the absolute value of the color coordinate b of the 3D chemically strengthened glass-ceramics is ≤0.4, and the haze is ≤0.15. When the chemically strengthened glass-ceramics are used as 3D chemically strengthened glass-ceramics, they still have excellent puncture resistance to rough ground and light transmittance.

[0031] On the other hand, an embodiment of the present application provides a method for preparing the chemically strengthened glass-ceramics of the embodiment of the present application. The method for preparing the chemically strengthened glass-ceramics of the embodiment of the present application includes the following steps:

[0032] Subject the as-prepared glass-ceramics to be chemically strengthened to a first chemical strengthening treatment in a sodium salt bath to form a Na / Li exchange layer.

[0033] In the method for preparing the chemically strengthened glass-ceramics of the present application, the as-prepared glass-ceramics are subjected to a first chemical strengthening treatment in a sodium salt bath, so that a Na / Li exchange layer is formed on the surface layer of the as-prepared glass-ceramics. By controlling the first chemical strengthening treatment, the chemically strengthened glass-ceramics formed by chemical strengthening can have the depth of the compressive stress layer, the range of the compressive stress intensity CS50, and the relationship between the two as described in the chemically strengthened glass-ceramics of the embodiment of the present application above. Therefore, the prepared chemically strengthened glass-ceramics have relatively high compressive stress, the stress intensity is greatly improved, the crack propagation can be resisted, and they have excellent puncture resistance to rough ground. In addition, the chemical strengthening conditions of the method for preparing the chemically strengthened glass-ceramics of the present application are easy to control, so that the prepared chemically strengthened glass-ceramics have stable performance, high efficiency, and reduced preparation cost.

[0034] Optionally, the sodium salt bath includes NaNO3 or a mixed salt of NaNO3 and KNO3. In the mixed salt of NaNO3 and KNO3, the content of NaNO3 is ≥50 wt%.

[0035] Optionally, the temperature of the first chemical strengthening treatment is 380-450°C, and the strengthening time is 0.5-6 h.

[0036] By controlling the type of the sodium salt bath, the content of NaNO3, and the first chemical strengthening treatment, the chemical strengthening treatment effect on the as-prepared glass-ceramics is improved, the depth of the compressive stress layer and the range of the compressive stress intensity CS50 of the formed chemically strengthened glass-ceramics are optimized, so as to increase the compressive stress of the chemically strengthened glass-ceramics and improve their puncture resistance to rough ground and light transmittance performance.

[0037] Optionally, after one chemical strengthening treatment, it further includes subjecting the chemically strengthened glass-ceramics with a Na / Li exchange layer formed thereon to a secondary chemical strengthening treatment in a potassium salt bath to form a K / Na exchange layer. By further subjecting the chemically strengthened glass-ceramics formed by the first chemical strengthening treatment to a secondary chemical strengthening treatment, a K / Na exchange layer is formed on the surface layer of the formed chemically strengthened glass-ceramics, thereby further improving the impact resistance and the resistance to dropping on a rough ground of the chemically strengthened glass-ceramics.

[0038] Furthermore, the potassium salt bath includes KNO3 or a mixed salt of NaNO3 and KNO3; in the mixed salt of NaNO3 and KNO3, the content of KNO3 is ≥80 wt%; and / or

[0039] Furthermore, the temperature of the secondary chemical strengthening treatment is 380 - 450 °C, and the strengthening time is 0.2 - 1 h.

[0040] By controlling the type of the potassium salt bath, the content of KNO3, and the secondary chemical strengthening treatment, the effect of the secondary chemical strengthening treatment is improved, and the impact resistance and the resistance to dropping on a rough ground of the chemically strengthened glass-ceramics are further improved.

[0041] Optionally, before subjecting the virgin glass-ceramics to be chemically strengthened to a first chemical strengthening treatment in a sodium salt bath, it further includes the step of subjecting the virgin glass-ceramics to the following thermal bending treatment:

[0042] Subject the virgin glass-ceramics to a single-stage thermal bending treatment at 650 - 750 °C for 30 - 120 s to form 3D virgin glass-ceramics, wherein the pressure of the single-stage thermal bending treatment is 0.1 - 0.9 MPa.

[0043] By subjecting the virgin glass-ceramics to a thermal bending treatment to form 3D virgin glass-ceramics, after the above-mentioned first chemical strengthening treatment or further after the secondary chemical strengthening treatment, 3D-shaped chemically strengthened glass-ceramics can be formed, and it is ensured that the 3D-shaped chemically strengthened glass-ceramics have high compressive stress and excellent puncture resistance and light transmittance on a rough ground.

[0044] On the other hand, an embodiment of the present application provides an electronic device. The electronic device in the embodiment of the present application includes a glass component, and the glass component is the chemically strengthened glass-ceramics in the above-mentioned embodiment of the present application or the chemically strengthened glass-ceramics prepared according to the preparation method of the chemically strengthened glass-ceramics in the above-mentioned embodiment of the present application. Since the chemically strengthened glass-ceramics in the embodiment of the present application have the above-mentioned excellent puncture resistance and optical properties on a rough ground or further have excellent impact resistance, therefore, the glass component is given excellent drop and fall resistance, and high strength, thereby giving the electronic device in the embodiment of the present application excellent drop and fall resistance and impact resistance, and the quality and working performance stability of the electronic device are high.

[0045] Further, the glass component includes at least one of a display cover plate, a protection cover plate, and a protection screen. The glass component has good light transmittance, strong protection, is resistant to dropping and falling, and has high strength. Its display or protection performance is good and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the mechanism for the microcrystalline glass to resist puncture;

[0047] Figure 2 It is a stress curve graph of existing aluminosilicate first-strength glass, lithium aluminosilicate second-strength glass, and the chemically strengthened microcrystalline glass of the embodiment of the present application;

[0048] Figure 3 It is a schematic process flow diagram of the preparation method of the chemically strengthened microcrystalline glass of the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application clearer and more understandable, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] In the description of the present application, it should be understood that the term "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Wherein A and B may be singular or plural. The character " / " generally represents that the associated objects before and after are an "or" relationship.

[0051] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one (item)" or similar expressions thereof refer to any combination of these items, including any combination of single item (item) or plural items (items). For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can all represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0052] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms of "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0053] In the embodiments of the present application, the term "and / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0054] It should be understood that in various embodiments of the present application, the order of the serial numbers of the above processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0055] The weight of the relevant components mentioned in the specification of the embodiments of the present application can not only refer to the specific content of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the content of the relevant components in the specification of the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0056] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX can also be referred to as the second XX. Similarly, the second XX can also be referred to as the first XX. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0057] Explanation of relevant special names below:

[0058] Plain glass-ceramics: Glass-ceramics that have not been strengthened.

[0059] Chemically strengthened glass-ceramics: Chemically tempered glass-ceramics that have been processed by a high-temperature ion exchange process. Large alkali metal ions replace small alkali metal ions in the glass in a high-temperature molten salt, thereby generating an exchange ion volume difference, and generating a compressive stress from high to low in the surface layer of the plain glass, hindering and delaying the propagation of glass microcracks, and achieving the purpose of improving the mechanical strength of the glass.

[0060] Depth of compressive stress layer (Doc): The depth of the compressive stress layer of chemically strengthened glass-ceramics.

[0061] Compressive stress value at 50 μm depth in the surface layer of chemically strengthened glass (CS50): Represents the compressive stress value at 50 μm depth in the surface layer of chemically strengthened glass-ceramics.

[0062] Na / Li exchange layer: It refers to the sodium-containing layer in chemically strengthened glass-ceramics where sodium ions replace some lithium ions.

[0063] K / Na exchange layer: It refers to the potassium-containing layer in chemically strengthened glass-ceramics where potassium ions replace some sodium ions.

[0064] Sodium-lithium ion exchange: In chemical strengthening, sodium ions in the salt bath replace lithium ions in the glass.

[0065] Potassium-sodium ion exchange: In chemical strengthening, potassium ions in the salt bath replace sodium ions in the glass.

[0066] On the one hand, the embodiments of the present application provide a chemically strengthened glass-ceramic. The chemically strengthened glass-ceramic of the embodiments of the present application has a Na / Li exchange layer and a compressive stress layer. It has been measured that the stress curve of the chemically strengthened glass-ceramic of the embodiments of the present application is as Figure 2 shown, and its compressive stress layer depth and compressive stress strength have at least the following 1 to 3 characteristics:

[0067] 1. The relationship between the compressive stress layer depth Doc of the chemically strengthened glass-ceramic and the total thickness of the chemically strengthened glass-ceramic satisfies the relationship shown in Equation 1-1 as follows:

[0068] Doc = 0.15t ~ 0.22t (1-1).

[0069] 2. The compressive stress strength on the surface layer of the chemically strengthened glass-ceramic satisfies the relationship shown in Equation 1-2 as follows:

[0070] The compressive stress strength CS50 at a surface strengthening depth of 50 μm of the chemically strengthened glass-ceramic satisfies the relationship shown in Equation 1-2 as follows:

[0071] CS50 = 130 + (20t - 13) × 15 MPa ~ 230 + (20t - 13) × 15 MPa; (1-2).

[0072] 3. The relationship between the compressive stress strength on the surface layer of the chemically strengthened glass-ceramic and the compressive stress layer depth Doc satisfies the relationship shown in Equation 1-3 as follows:

[0073] CS50 / (Doc - 50) = 1.4 ~ 6, with the unit of MPa / μm; (1-3).

[0074] Among them, t in Equation 1-1 and Equation 1-2 is the total thickness of the chemically strengthened glass-ceramic. Therefore, t is a positive number greater than 0, and the unit can be mm. In the embodiment, t is also the total thickness of the chemically strengthened glass-ceramic of the embodiments of the present application, which is 0.3 ~ 0.8 mm.

[0075] The surface strengthening depth at 50 μm related to Formula 1-2 refers to the region with an internal depth of 50 μm from the surface of the chemically strengthened glass-ceramics towards the interior. During the experiment, it was found that when the CS50 of the chemically strengthened glass-ceramics in the embodiments of the present application is too small, it will lead to a decrease in the puncture resistance of the chemically strengthened glass-ceramics, such as the ability to resist rough ground punctures, and the reliability is affected; when CS50 is too high, the broken fragments of the chemically strengthened glass-ceramics are too small.

[0076] In addition, from Figure 2 the existing aluminosilicate single-strength glass shown in (the main components contain SiO2 + Al2O3 + B2O3 + P2O5 = 75 - 85 mol%, Na2O + K2O = 10 - 16 mol%, without Li2O; its strengthening process generally uses pure KNO3 for strengthening at 380 - 460 °C for 1 - 10 h), after strengthening, CS ≥ 700 MPa, CS50 ≈ 0; the strengthening layer depth (K / Na) exchange layer depth is 0.04 - 0.09t. The existing lithium aluminosilicate double-strength glass (the main components contain SiO2 + Al2O3 + B2O3 + P2O5 = 75 - 85 mol%, Li2O + Na2O + K2O = 10 - 20 mol%. The strengthening process generally uses a double-strength process: strengthening one uses pure NaNO3 or a NaNO3 / KNO3 mixed salt, the strengthening temperature is 380 - 450 °C, and strengthening two uses pure KNO3 or a NaNO3 / KNO3 mixed salt), after strengthening, CS ≥ 700 MPa, the potassium layer strengthening depth Dol ≥ 5 μm, CS50 < 130 + (20t - 13) × 15 MPa, and the compressive stress layer strengthening depth Doc ≥ 0.18t.

[0077] Based on the above-mentioned fact that the chemically strengthened glass-ceramics in the embodiments of the present application have the above-mentioned specific compressive stress layer depth, compressive stress intensity, and the relationship between the compressive stress layer depth and the compressive stress intensity, therefore, compared with the existing aluminosilicate single-strength glass and lithium aluminosilicate double-strength glass, the chemically strengthened glass-ceramics in the embodiments of the present application have a relatively high compressive stress, and the stress intensity is greatly improved compared with the current aluminosilicate glass and glass-ceramics, and can resist crack propagation. Compared with the commonly used strengthened glass in the current life scenario (such as the rough ground puncture depth where current mobile phones commonly fail in the life scenario is generally 40 - 70 μm), the puncture resistance of the chemically strengthened glass-ceramics in the embodiments of the present application to rough ground is significantly improved, and the drop height on rough ground is higher than that of the existing aluminosilicate glass and glass-ceramics. Among them, Figure 2 the curve of the aluminosilicate single-strength glass (K / Na exchange) in is tested by the industry-standard surface stress testing equipment FSM-6000LEUV, and the curve of the lithium aluminosilicate double-strength glass (simultaneously having K / Na and Na / Li exchanges) is synthesized by fitting the industry-standard surface stress testing equipment FSM-6000LEUV and the scattered light photoelastic stress instrument SLP2000; the curve of the chemically strengthened glass-ceramics of the present application is tested by SLP2000.

[0078] It is further measured that the chemically strengthened glass-ceramics of the embodiments of the present application also have the following relevant mechanical properties, optical properties, etc.:

[0079] In the embodiment, when a 10-mm diameter round-headed metal pressing rod is used to extrude the chemically strengthened glass-ceramics until it breaks, the average size of the longest side of the fragments is ≥5 mm. Therefore, the internal tensile stress of the chemically strengthened glass-ceramics is appropriate, and the ability to resist puncture by a rough ground is strong, avoiding the risk of self-explosion.

[0080] In the embodiment, when the thickness is 0.6 mm, the sandpaper drop height of the chemically strengthened glass-ceramics is ≥1.5 m, reflecting the excellent drop resistance of the chemically strengthened glass-ceramics. The sandpaper drop height data is tested under the scenario of 180# sandpaper / 200 g load. Specifically, the plane of the chemically strengthened glass-ceramics to be tested is facing downwards, and a standard 200-g load is applied to the other surface. The drop starts from 0.5 m, and the appearance is checked after each drop; if there is no problem, it is lifted by 0.1 m until the glass breaks, and the failure height is recorded.

[0081] In the embodiment, when stored in an environment of 85°C temperature / 85% humidity for 72 h, no sodium salt precipitation appears on the outer surface of the chemically strengthened glass-ceramics, reflecting the excellent thermal and humidity stability of the chemically strengthened glass-ceramics.

[0082] In the embodiment, when the thickness of the chemically strengthened glass-ceramics is ≤0.8 mm, the average light transmittance at wavelengths of 400-940 nm is ≥89.5%, the single-point transmittance difference between 550 nm and 400 nm wavelengths is <1%, the absolute value of the color coordinate b is ≤0.4, and the haze is ≤0.15. This reflects the excellent optical properties such as light transmittance of the chemically strengthened glass-ceramics.

[0083] Therefore, based on the above-mentioned depth of the compressive stress layer, compressive stress intensity, and the relationship between the depth of the compressive stress layer and the compressive stress intensity of the chemically strengthened glass-ceramics, the chemically strengthened glass-ceramics not only have a high compressive stress intensity, have an excellent ability to resist puncture by a rough ground, and have a high drop resistance height, as shown in Table 1 below; but also have excellent thermal and humidity stability and good optical properties such as light transmittance.

[0084] In the embodiments, the main crystal phase of the base microcrystalline glass used to form the above-mentioned chemically strengthened microcrystalline glass is any one of lithium silicate or β-quartz solid solution, and the total mass fraction of the crystal phases contained is 35-75%, wherein the total content of the secondary crystal phases is <5%. By controlling the type and content of the main crystal phase of the base microcrystalline glass, it is possible to effectively prevent the Na / Li exchange layer contained in the chemically strengthened microcrystalline glass from being adversely affected by Li, and it is possible to effectively control the CS50 range, thereby further improving the puncture resistance of the chemically strengthened microcrystalline glass to rough ground. At the same time, it can also improve the optical properties such as light transmittance of the chemically strengthened microcrystalline glass.

[0085] In some embodiments, the above-mentioned base microcrystalline glass includes a main composition and a nucleating agent; wherein, the main composition includes SiO2, Al2O3, B2O3, Li2O, Na2O, K2O, and satisfies: the content of SiO2+Al2O3+B2O3 is 58-85 mol%; the content of Li2O+Na2O+K2O is 10-32 mol%; the nucleating agent includes TiO2, P2O5, ZrO2, and satisfies: the content of TiO2+P2O5+ZrO2 is 2-8 mol%. These components of the base microcrystalline glass endow the base microcrystalline glass and the chemically strengthened microcrystalline glass with the above-mentioned type of main crystal phase and crystal phase content, thereby improving the puncture resistance of the chemically strengthened microcrystalline glass to rough ground and the optical properties such as light transmittance of the chemically strengthened microcrystalline glass.

[0086] In the embodiments, the above-mentioned base microcrystalline glass can be prepared by a melting casting method or a rolling method. In some embodiments, the above-mentioned base microcrystalline glass undergoes the following two-step heat treatment:

[0087] The first heat treatment: the temperature is 500-600 °C, and the treatment time is 0.1-10 h;

[0088] The second heat treatment: the temperature is 640-800 °C, and the treatment time is 0.1-10 h.

[0089] By the preparation method of the base microcrystalline glass or further adopting this two-step heat treatment, the main crystal phase and its content required to obtain the crystallinity of the base microcrystalline glass are formed, and the main crystal phase and crystal phase content can be adjusted, thereby realizing the improvement of the puncture resistance of the chemically strengthened microcrystalline glass to rough ground and the optical properties.

[0090] Due to the type and content of the main crystal phase of the base microcrystalline glass, it is detected that the base microcrystalline glass also has excellent mechanical properties such as Young's modulus and optical properties such as light transmittance.

[0091] In the embodiment, when the thickness of the plain glass-ceramics is ≤ 0.8 mm, the average light transmittance at a wavelength of 400 - 940 nm is ≥ 89.5%, the single-point transmittance difference between 550 nm and 400 nm is < 1%, the absolute value of the color coordinate b is ≤ 0.3, and the haze is ≤ 0.14. By controlling the types and contents of the main crystal phases of the plain glass-ceramics, the plain glass-ceramics have good optical properties such as light transmittance, and the optical properties are stable.

[0092] In the embodiment, the Young's modulus of the plain glass-ceramics is ≥ 95 GPa. Based on the types and contents of the main crystal phases of the plain glass-ceramics, the plain glass-ceramics are given a high Young's modulus, and thus the chemically strengthened glass-ceramics are given a high Young's modulus. For example, the Young's modulus of the chemically strengthened glass-ceramics is ≥ 95 GPa, thereby endowing the chemically strengthened glass-ceramics with a larger storage space for compressive stress, providing conditions for the improvement of the compressive stress of the chemically strengthened glass-ceramics. Moreover, the plain glass-ceramics and the chemically strengthened glass-ceramics are given high impact resistance. For example, it is detected that the chemically strengthened glass-ceramics are about 25 - 30 GPa higher than the existing aluminosilicate glass, effectively reducing the requirements and dependence of the chemically strengthened glass-ceramics on the K / Na exchange layer.

[0093] In the embodiment, the surface layer of the chemically strengthened glass-ceramics in each of the above embodiments further has a K / Na exchange layer. Further forming a K / Na exchange layer on the surface layer of the chemically strengthened glass-ceramics is to increase the potassium layer on the surface layer of the chemically strengthened glass-ceramics. On the basis that the chemically strengthened glass-ceramics have high puncture resistance to rough ground, the drop resistance of the chemically strengthened glass-ceramics to rough ground is further optimized and improved, and the impact resistance of the chemically strengthened glass-ceramics is further improved.

[0094] Moreover, based on the high Young's modulus of the chemically strengthened glass-ceramics in the embodiment of the present application, such as the Young's modulus ≥ 95 GPa, this high Young's modulus supports good impact strength and effectively reduces the dependence on the K / Na exchange layer. As Figure 2 shown in the stress curve, compared with the curve of the existing aluminosilicate single-strength glass, the chemically strengthened glass-ceramics in the embodiment of the present application do not require a large K / Na exchange layer. In the embodiment, the thickness of the K / Na exchange layer contained in the chemically strengthened glass-ceramics in each of the above embodiments is ≤ 3 μm. By controlling the thickness of the K / Na exchange layer (potassium layer), the impact resistance and the drop resistance of the chemically strengthened glass-ceramics to rough ground can be further improved. And on the basis of the above-mentioned depth of the compressive stress layer, the strength of the compressive stress, and the relationship between the depth of the compressive stress layer and the strength of the compressive stress, the thickness requirement of the K / Na exchange layer can be effectively reduced.

[0095] Based on the above embodiments, the chemically strengthened glass-ceramics have excellent puncture resistance to rough ground, drop resistance, and optical properties such as light transmission, or further have a high Young's modulus and impact resistance. The chemically strengthened glass-ceramics in the embodiments of the present application can be any one of 2D chemically strengthened glass-ceramics, 2.5D chemically strengthened glass-ceramics, and 3D chemically strengthened glass-ceramics. The above excellent puncture resistance to rough ground and optical properties of the chemically strengthened glass-ceramics expand their application range and improve the quality and performance stability of corresponding products.

[0096] When the chemically strengthened glass-ceramics in the above embodiments are 2D chemically strengthened glass-ceramics or 2.5D chemically strengthened glass-ceramics, in the embodiments, the CS50 and Doc of the chemically strengthened glass-ceramics satisfy: CS50 / (Doc - 50) is 1.4 to 6.

[0097] In some other embodiments, when the thickness of the chemically strengthened glass-ceramics is ≤ 0.8 mm, the average light transmittance at 400 - 940 nm is ≥ 89.5%, the single-point transmittance difference between 550 nm and 400 nm wavelengths is < 1%, the absolute value of the color coordinate b is ≤ 0.3, and the haze is ≤ 0.14.

[0098] Therefore, when the chemically strengthened glass-ceramics are 2D chemically strengthened glass-ceramics or 2.5D chemically strengthened glass-ceramics, they have excellent puncture resistance to rough ground and light transmittance. Compared with the optical properties of the plain glass-ceramics, their optical properties such as light transmittance remain stable.

[0099] When the chemically strengthened glass-ceramics in the above embodiments are 3D chemically strengthened glass-ceramics, in the embodiments, the long-side bending angle of the 3D chemically strengthened glass-ceramics is 15 to 89°. Moreover, the CS50, Doc of the chemically strengthened glass-ceramics, and the relationship between CS50 and Doc satisfy the characteristics shown in the above formulas 1-1 to 1-3, and still have excellent puncture resistance to rough ground. Of course, at the same time, they still have excellent impact resistance. The measured optical characteristics are that the average light transmittance at 400 - 940 nm is ≥ 89.5%, the single-point transmittance difference between 550 nm and 400 nm wavelengths is < 1%, the absolute value of the color coordinate b is ≤ 0.4, and the haze is ≤ 0.15. Although there are slight differences compared with the optical properties of the plain glass-ceramics, the differences are not obvious. Therefore, when the chemically strengthened glass-ceramics in the above embodiments are 3D chemically strengthened glass-ceramics, they still have excellent optical properties such as light transmittance remaining stable.

[0100] On the other hand, the embodiments of the present application provide the preparation method of the chemically strengthened glass-ceramics in the above embodiments of the present application. The process flow of the preparation method of the chemically strengthened glass-ceramics in the embodiments of the present application is as Figure 3 shown, and includes the following steps:

[0101] S01: Subject the virgin glass-ceramics to be chemically strengthened to a first chemical strengthening treatment in a sodium salt bath to form a Na / Li exchange layer.

[0102] During the first chemical strengthening treatment, sodium ions in the sodium salt bath diffuse into the surface layer of the virgin glass-ceramics under the action of heat and exchange with lithium ions in the surface layer of the virgin glass-ceramics, that is, sodium-lithium ion exchange occurs, so that a Na / Li exchange layer is formed in the surface layer of the virgin glass-ceramics. By controlling the first chemical strengthening treatment, the chemically strengthened glass-ceramics formed by chemical strengthening can have the depth of the compressive stress layer and the range of the compressive stress intensity CS50 as shown in Formulas 1-1 to 1-3 in the above embodiments of the present application, and the relationship between the two, thereby endowing the prepared chemically strengthened glass-ceramics with relatively high compressive stress, greatly improving the stress intensity, being able to resist crack propagation, and having excellent puncture resistance to rough ground. In addition, the chemical strengthening conditions of the preparation method of the chemically strengthened glass-ceramics in the present application are easy to control, so that the prepared chemically strengthened glass-ceramics have stable performance, high efficiency, and reduced preparation cost.

[0103] In the embodiment, the sodium salt bath includes NaNO3 or a mixed salt of NaNO3 and KNO3. When the sodium salt bath is a mixed salt of NaNO3 and KNO3, the content of NaNO3 in the mixed salt of NaNO3 and KNO3 is ≥50 wt%. In the embodiment, the temperature of the first chemical strengthening treatment is 380-450 °C, and the strengthening time is 0.5-6 h. By controlling the type of the sodium salt bath, the content of NaNO3, and the first chemical strengthening treatment, the chemical strengthening treatment effect on the virgin glass-ceramics is improved, the depth of the compressive stress layer and the range of the compressive stress intensity CS50 of the formed chemically strengthened glass-ceramics are optimized, thereby improving the compressive stress of the chemically strengthened glass-ceramics and its puncture resistance to rough ground and light transmittance.

[0104] In addition, the virgin glass-ceramics to be chemically strengthened are the virgin glass-ceramics of the above chemically strengthened glass-ceramics, such as any one of lithium silicate or β-quartz solid solution as the main crystal phase, and the total crystal phase mass fraction contained is 35-75%, and the total content of the secondary crystal phase is <5 wt%. In a specific embodiment, the virgin glass-ceramics include a main composition and a nucleating agent; the main composition includes SiO2, Al2O3, B2O3, Li2O, Na2O, K2O, and satisfies: the content of SiO2+Al2O3+B2O3 is 58-85 mol%; the content of Li2O+Na2O+K2O is 10-32 mol%; the nucleating agent includes TiO2, P2O5, ZrO2, and satisfies: the content of TiO2+P2O5+ZrO2 is 2-8 mol%.

[0105] In the embodiment, when the prepared chemically strengthened microcrystalline glass is a 3D-shaped chemically strengthened microcrystalline glass, before the green microcrystalline glass to be chemically strengthened is subjected to a primary chemical strengthening treatment in a sodium salt bath, the following steps of thermoforming the green microcrystalline glass are further included:

[0106] The green microcrystalline glass is subjected to a single-stage thermoforming treatment at 650-750 °C for 30-120 s to form a 3D green microcrystalline glass, wherein the pressure of the single-stage thermoforming treatment is 0.1-0.9 MPa.

[0107] By thermoforming the green microcrystalline glass to form a 3D green microcrystalline glass, after the above-mentioned primary chemical strengthening treatment or further secondary chemical strengthening treatment, a 3D-shaped chemically strengthened microcrystalline glass can be formed, and it is ensured that the 3D-shaped chemically strengthened microcrystalline glass has high compressive stress and excellent puncture resistance and light transmittance against rough ground.

[0108] In a specific embodiment, the long-side bending angle of the 3D green microcrystalline glass is 15-89°. In some other specific embodiments, the absolute value of the change difference of the color coordinate b value of the 3D green microcrystalline glass is ≤0.1. By controlling the above-mentioned thermoforming treatment conditions, the prepared 3D green microcrystalline glass has the required long-side bending angle and stable optical properties.

[0109] Compared with the existing microcrystalline glass, such as the microcrystalline glass with spodumene and lithium disilicate as the main crystal phases mentioned in the background art part, the thermoforming temperature of the existing microcrystalline glass with spodumene and lithium disilicate as the main crystal phases is >750 °C, and the crystal phase size grows during the thermoforming process, resulting in a sharp deterioration of the optical properties after 3D forming (the absolute value of the color difference b ≥2, the haze ≥0.25%); it cannot meet the application of thermoformed 3D CG cover plates. However, for any one of the above-mentioned green microcrystalline glasses with lithium silicate or β-quartz solid solution as the main crystal phase in the embodiment of the present application, the above-mentioned maximum thermoforming temperature of 650-750 °C is adopted. Before and after thermoforming, the absolute value of the change difference of the glass color coordinate b value is ≤0.1, the absolute value of the color coordinate b is ≤0.4, and the haze is ≤0.14; it meets the application of 3D thermoformed 3D CG cover plates.

[0110] In the embodiment, after the above-mentioned primary chemical strengthening treatment, the following steps are further included as Figure 3 Step S02 in: The chemically strengthened microcrystalline glass formed with a Na / Li exchange layer is subjected to a secondary chemical strengthening treatment in a potassium salt bath to form a K / Na exchange layer.

[0111] During the secondary chemical strengthening treatment, potassium ions in the potassium salt bath diffuse into the surface layer of the chemically strengthened microcrystalline glass under the action of heat and exchange with sodium ions in the Na / Li exchange layer, that is, potassium-sodium ion exchange is carried out to form a K / Na exchange layer in the surface layer of the chemically strengthened microcrystalline glass, thereby further improving the impact resistance and the drop resistance against rough ground of the chemically strengthened microcrystalline glass.

[0112] In the embodiment, the potassium-containing salt bath includes KNO3 or a mixed salt of NaNO3 and KNO3; when the potassium-containing salt bath is a mixed salt of NaNO3 and KNO3, in the mixed salt of NaNO3 and KNO3, the content of KNO3 is ≥80 wt%. In the embodiment, the temperature of the secondary chemical strengthening treatment is 380-450 °C, and the strengthening time is 0.2-1 h. By controlling the type of the potassium-containing salt bath, the content of KNO3, and the secondary chemical strengthening treatment, the effect of the secondary chemical strengthening treatment is improved, and the impact resistance and the resistance to dropping on a rough ground of the chemically strengthened glass-ceramics are further improved.

[0113] In addition, the chemically strengthened glass-ceramics prepared by the chemically strengthened glass-ceramics and the preparation method of the present application embodiment are compared with the existing glass-ceramics, such as the glass-ceramics with spodumene and lithium disilicate as the main crystal phases mentioned in the background art part. Since the existing glass-ceramics with spodumene and lithium disilicate as the main crystal phases have a relatively high crystallinity (this material contains multiple main crystal phases and requires a relatively high crystallinity to maintain excellent optical properties), ion exchange requires a greater potential energy, so a higher chemical strengthening temperature / a longer chemical strengthening time is required; moreover, this glass-ceramics is sensitive to the Li concentration in the chemical strengthening furnace water, and the Li concentration needs to be precisely controlled during the chemical strengthening process, and is limited by the inhibition of Na / Li exchange by Li during the chemical strengthening process. Therefore, for the chemically strengthened glass-ceramics formed by the chemical strengthening of the existing glass-ceramics, CS50 < 130 + (20t - 13) × 15 MPa. However, for the chemically strengthened glass-ceramics of the present application embodiment, especially the chemically strengthened glass-ceramics containing any one of the main crystal phases lithium silicate or β-quartz solid solution, its crystallinity is relatively low, such as the crystallinity ≤ 75 wt%; the chemical strengthening treatment process is not sensitive to Li; the CS50, Doc, and the relationship between CS50 and Doc of the chemically strengthened glass-ceramics obtained by the chemical strengthening treatment satisfy the characteristics shown in the above formulas 1-1 to 1-3. Especially, CS50 is between 130 + (20t - 13) × 15 MPa and 230 + (20t - 13) × 15 MPa, so as to obtain better anti-piercing ability on a rough ground.

[0114] On the other hand, based on the above chemically strengthened glass-ceramics and the preparation method thereof, the present application embodiment provides an electronic device. The electronic device of the present application embodiment includes a glass component, and the glass component is the chemically strengthened glass-ceramics of the present application embodiment above. In this way, since the chemically strengthened glass-ceramics of the present application embodiment has the excellent anti-piercing ability on a rough ground, optical properties, and impact resistance as described above, the glass component is given excellent anti-drop and anti-fall properties and high strength. Then, the electronic device of the present application embodiment including the glass component also has excellent anti-drop and anti-fall properties and impact resistance, and the quality and working performance stability of the electronic device are high.

[0115] In an embodiment, at least one of a display cover plate, a protection cover plate, and a protection screen included in an electronic device. The glass component has good light transmittance, good display effect, and can also play a good protective role. At the same time, it is anti-drop, anti-fall, and has high strength. Its display or protection performance is good, making the electronic device stable. The glass component can also be any one of 2D chemically strengthened microcrystalline glass, 2.5D chemically strengthened microcrystalline glass, and 3D chemically strengthened microcrystalline glass, which expands and enhances the application range of chemically strengthened microcrystalline glass and improves the stability of the quality and performance of the corresponding electronic device.

[0116] In an embodiment, the electronic device includes at least one of a communication mobile terminal, an electronic watch, a bracelet, and a computer. In a specific embodiment, when the electronic device is a communication mobile terminal such as a mobile phone, the glass component included therein can be used as the front and rear cover plates of the mobile phone. Since these electronic devices contain the glass component, these electronic devices have excellent anti-drop performance or further have excellent impact resistance and high strength, thereby making the performance of the electronic device stable.

[0117] The above-mentioned chemically strengthened microcrystalline glass and its preparation method will be elaborated in detail below in conjunction with specific embodiments.

[0118] Example 1

[0119] This embodiment provides a 3D β - quartz solid solution chemically strengthened microcrystalline glass and its chemical strengthening method. The relevant properties of the chemically strengthened microcrystalline glass and the relevant process parameters of its chemical strengthening method are as described in Table 2 below.

[0120] Among them, the preparation method of the chemically strengthened microcrystalline glass includes the following steps:

[0121] S1: Preparation of the base microcrystalline glass and its preparation:

[0122] (1) The glass matrix is prepared by the melting casting method, and its composition is SiO2 + Al2O3 + B2O3 = 85 mol%; Li2O + Na2O + K2O = 10 mol%; the nucleating agent TiO2 + P2O5 + ZrO2 = 2 mol%, and other components are MgO;

[0123] (2) The prepared glass matrix is subjected to two-step heat treatment to obtain the required crystal phase; the first heat treatment is at 600 °C for 0.1 h, and the second heat treatment is at 750 - 900 °C for 0.1 h. The main crystal phase of the obtained crystal is β - quartz solid solution, and the crystallinity obtained by XRD test is 35 wt%;

[0124] S2: Preparation of the 3D base microcrystalline glass and its preparation:

[0125] The β - quartz solid - solution glass - ceramics prepared in step S1 are cut / ground / polished into glass wafers with a thickness of 0.35 mm; then they are thermally bent into a 3D shape using a 3D graphite mold, where the maximum thermal bending temperature is 650 °C, the thermal bending compressive stress is 0.9 MPa, and the single - station thermal bending time is 30 s;

[0126] S3: The 3D glass after thermal bending in step S2 is polished on the concave - convex surface using a 3D polishing brush (the thickness after polishing is 0.3 mm), and then chemically strengthened to form 3D - shaped β - quartz solid - solution chemically strengthened glass - ceramics; the chemical strengthening conditions are shown in Table 2.

[0127] Example 2

[0128] This example provides a 2.5D - shaped lithium silicate chemically strengthened glass - ceramics and its chemical strengthening method. The relevant properties of the chemically strengthened glass - ceramics and the relevant process parameters of its chemical strengthening method are as described in Table 2 below.

[0129] Among them, the preparation method of the chemically strengthened glass - ceramics includes the following steps:

[0130] S1: Green glass - ceramics and their preparation:

[0131] (1) A glass matrix is prepared by the melting - casting method, and its composition is SiO2 + Al2O3 + B2O3 = 58 mol%; Li2O + Na2O + K2O = 32 mol%; the nucleating agents TiO2 + P2O5 + ZrO2 = 8 mol%, and other components are 2% MgO;

[0132] (2) The prepared glass matrix is subjected to two - step heat treatment to obtain the desired crystal phase; the first heat treatment is at 500 °C for 10 h, and the second heat treatment is at 640 °C for 10 h. The main crystal phase of the obtained crystals is lithium silicate, and the crystallinity obtained by XRD testing is 75 wt%;

[0133] S2: 2.5D green glass - ceramics and their preparation:

[0134] The lithium - silicate green glass - ceramics prepared in step S1 are cut / ground / machined by computer numerical control (CNC) / polished into a 2.5D - shaped carrier with a thickness of 0.65 mm;

[0135] S3: The 2.5D green glass - ceramics in step S2 are polished on the concave - convex surface using a polishing brush and then chemically strengthened to form 2.5D - shaped lithium silicate chemically strengthened glass - ceramics. The finished product has a thickness of 0.6 mm, and the chemical strengthening conditions are shown in Table 2.

[0136] Example 3

[0137] This embodiment provides a 3D-shaped lithium silicate chemically strengthened glass-ceramics and its chemical strengthening method. The relevant properties of the chemically strengthened glass-ceramics and the relevant process parameters of its chemical strengthening method are as described in Table 2 below.

[0138] Among them, the preparation method of the chemically strengthened glass-ceramics includes the following steps:

[0139] S1: Preparation of the raw glass-ceramics:

[0140] (1) The glass matrix is prepared by the melting casting method, and its component composition is SiO2 + Al2O3 + B2O3 = 65 mol%; Li2O + Na2O + K2O = 30 mol%; the nucleating agent TiO2 + P2O5 + ZrO2 = 5 mol%;

[0141] (2) The prepared glass matrix is subjected to two-step heat treatment to obtain the required crystal phase; the first heat treatment is at 550 °C for 6 h, and the second heat treatment is at 800 °C for 2 h. The main crystal phase of the obtained crystal is lithium silicate, and the crystallinity obtained by XRD test is 65 wt%.

[0142] S2: Preparation of the 3D raw glass-ceramics:

[0143] The lithium silicate raw glass-ceramics prepared in step S1 are cut / ground / polished into a glass wafer with a thickness of 0.7 mm; then it is hot-bent into a 3D shape by using a 3D graphite mold, where the highest hot-bending temperature is 750 °C, the hot-bending compressive stress is 0.1 MPa, and the single-station hot-bending time is 120 s;

[0144] S3: The raw glass-ceramics in step S2 are polished on the concave and convex surfaces by using a 3D polishing brush and then subjected to chemical strengthening treatment to form a 3D-shaped lithium silicate chemically strengthened glass-ceramics. The finished product thickness is 0.65 mm, and the chemical strengthening conditions are shown in Table 2.

[0145] Example 4

[0146] This embodiment provides a 2.5D-shaped lithium silicate chemically strengthened glass-ceramics and its chemical strengthening method. The relevant properties of the chemically strengthened glass-ceramics and the relevant process parameters of its chemical strengthening method are as described in Table 2 below.

[0147] Among them, the preparation method of the chemically strengthened glass-ceramics includes the following steps:

[0148] S1: Preparation of the raw glass-ceramics:

[0149] (1) The glass matrix is prepared by the melt casting method, and its composition is SiO2 + Al2O3 + B2O3 = 65 mol%; Li2O + Na2O + K2O = 30 mol%; the nucleating agent TiO2 + P2O5 + ZrO2 = 5 mol%;

[0150] (2) The prepared glass matrix is heat-treated in two steps to obtain the desired crystal phase; the first heat treatment is at 550 °C for 6 h, and the second heat treatment is at 800 °C for 2 h. The main crystal phase of the obtained crystal is lithium silicate, and the crystallinity obtained by XRD testing is 65 wt%;

[0151] S2: 2.5D monolithic glass-ceramics and its preparation:

[0152] The lithium silicate monolithic glass-ceramics prepared in step S1 are cut / ground / polished into a 2.5D glass original sheet with a thickness of 1 mm;

[0153] S3: The 2.5D monolithic glass-ceramics in step S2 are chemically strengthened, and the chemical strengthening conditions are shown in Table 1.

[0154] Testing of relevant properties of chemically strengthened glass-ceramics:

[0155] The above Examples 1 to 4 are respectively subjected to the relevant property tests in Table 2 below. The test methods are as follows, and the test results are shown in Table 1 below:

[0156] Table 1

[0157]

[0158] As can be seen from Table 1, in each example, the depth of the compressive stress layer Doc of the chemically strengthened glass-ceramics is in line with 0.15t - 0.22t of the thickness of the chemically strengthened glass-ceramics; the compressive stress intensity CS50 at a surface strengthening depth of 50 μm of each chemically strengthened glass-ceramics is in line with 130 + (20t - 13) × 15 MPa - 230 + (20t - 13) × 15 MPa of the thickness of the chemically strengthened glass-ceramics; CS50 and Doc satisfy the relationship that CS50 / (Doc - 50) is 1 - 7.5, and it has a high puncture resistance to rough ground, excellent optical properties such as light transmittance, and good thermal and humidity stability.

[0159] Furthermore, taking the existing aluminosilicate first-strength glass (K / Na exchange) with a thickness of 0.6 mm and the existing lithium aluminosilicate second-strength glass (with both K / Na and Na / Li exchanges) with a thickness of 0.6 mm in the industry as comparative examples, the CS50 (MPa) and the drop height test on the 180# sandpaper surface were respectively carried out on the chemically strengthened glass-ceramics obtained from the same original glass-ceramics and the same chemical strengthening treatment as those in the above Example 3. Among them, the shapes and thicknesses of the aluminosilicate first-strength glass, the lithium aluminosilicate second-strength glass, and the chemically strengthened glass-ceramics in the embodiment of the present application are the same. The test results are shown in Table 2 as follows:

[0160] Table 2

[0161]

[0162] As can be seen from Table 2, the CS50 and the drop height on the sandpaper surface of the chemically strengthened glass-ceramics in the embodiment of the present application are significantly higher than those of the existing aluminosilicate first-strength glass and the lithium aluminosilicate second-strength glass. Therefore, the ability of the chemically strengthened glass-ceramics in the embodiment of the present application to resist puncture by rough ground has been significantly improved. Therefore, using the chemically strengthened glass-ceramics provided in the embodiment of the present application in electronic products, such as as the front and rear covers of mobile phones, specifically, it can be a 2D cover, a 2.5D cover, a 3D cover, etc., so as to improve the drop resistance of mobile phones and other electronic products, endow the corresponding electronic products with excellent anti-drop performance, and also improve the impact resistance of mobile phones and other electronic products, thereby making the performance of electronic products stable.

[0163] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A chemically strengthened microcrystalline glass, characterized in that: It has a Na / Li exchange layer and a K / Na exchange layer, and the depth Doc of the compressive stress layer of the chemically strengthened glass-ceramics is 0.15t to 0.22t; The compressive stress intensity CS50 at a surface strengthening depth of 50 μm of the chemically strengthened glass-ceramics is 130 + (20t - 13) × 15 MPa to 230 + (20t - 13) × 15 MPa; And the CS50 and the Doc satisfy: CS50 / (Doc - 50) is 1.4 to 6, with the unit of MPa / μm; Wherein, t is the total thickness of the chemically strengthened glass-ceramics, and t is 0.3 to 0.8 mm; the thickness of the K / Na exchange layer ≤ 3 μm.

2. The chemically strengthened glass-ceramics according to claim 1, wherein: The main crystal phase of the chemically strengthened glass-ceramics is any one of lithium silicate or β-quartz solid solution.

3. The chemically strengthened microcrystalline glass according to claim 1 or 2, characterized in that, The total crystal phase mass fraction contained in the chemically strengthened glass-ceramics is 35 to 75%.

4. The chemically strengthened glass-ceramics according to claim 3, characterized in that, The total content of the mass fraction of the secondary crystal phase contained in the chemically strengthened glass-ceramics < 5%.

5. The chemically strengthened glass-ceramics according to claim 1, wherein: When extruding the chemically strengthened glass-ceramics to break with a 10 mm diameter round head metal pressure bar, the average size of the longest side of the fragments ≥ 5 mm.

6. The chemically strengthened microcrystalline glass according to claim 1, wherein: When the thickness is 0.6 mm, the sandpaper drop height of the chemically strengthened glass-ceramics ≥ 1.5 m.

7. The chemically strengthened glass-ceramics according to claim 1, characterized in that: When stored in an environment of temperature 85°C / humidity 85% for 72 h, no sodium salt precipitation appears on the outer surface of the chemically strengthened glass-ceramics.

8. The chemically strengthened glass-ceramics according to claim 1, wherein: When the thickness of the chemically strengthened glass-ceramics ≤ 0.8 mm, the average light transmittance at a wavelength of 400 - 940 nm ≥ 89.5%, and the single-point transmittance difference at wavelengths of 550 nm and 400 nm < 1%, the absolute value of the color coordinate b ≤ 0.4, and the haze ≤ 0.15%.

9. The chemically strengthened glass-ceramics according to claim 1, wherein: The Young's modulus of the chemically strengthened glass-ceramics ≥ 95 GPa.

10. The chemically strengthened glass-ceramics according to claim 1, wherein: The chemically strengthened glass-ceramics is any one of 2D-shaped chemically strengthened glass-ceramics, 2.5D-shaped chemically strengthened glass-ceramics, and 3D-shaped chemically strengthened glass-ceramics.

11. The chemically strengthened microcrystalline glass according to claim 10, wherein: The chemically strengthened glass-ceramics is 2D-shaped chemically strengthened glass-ceramics or / and 2.5D-shaped chemically strengthened glass-ceramics, and the absolute value of the color coordinate b of the 2D-shaped chemically strengthened glass-ceramics or / and 2.5D-shaped chemically strengthened glass-ceramics ≤ 0.3, and the haze ≤ 0.

14.

12. The chemically strengthened glass-ceramics according to claim 10, wherein: The chemically strengthened glass-ceramics is the 3D-shaped chemically strengthened glass-ceramics, and the long side bending angle is 15 to 89°; and / or The absolute value of the color coordinate b of the 3D-shaped chemically strengthened glass-ceramics ≤ 0.4, and the haze ≤ 0.

15.

13. The chemically strengthened glass-ceramics according to any one of claims 1-12, characterized in that: The chemically strengthened glass-ceramics includes main components: SiO2, Al2O3, B2O3, Li2O, Na2O, K2O, and satisfies: the content of SiO2 + Al2O3 + B2O3 is 58 - 85 mol%; the content of Li2O + Na2O + K2O is 10 - 32 mol%.

14. The chemically strengthened glass-ceramics according to claim 13, wherein: The chemically strengthened glass-ceramics further includes nucleating agents: TiO2, P2O5, ZrO2, and satisfies: the content of TiO2 + P2O5 + ZrO2 is 2 - 8 mol%.

15. An electronic device, characterized in that: It includes a glass component, and the glass component is the chemically strengthened glass-ceramics according to any one of claims 1 - 14.

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