Transparent glass-ceramics, chemically strengthened glass-ceramics, and their preparation methods and applications

Abstract

The present invention discloses transparent microcrystalline glass, chemically strengthened microcrystalline glass, and preparation methods and applications thereof, and relates to the technical field of microcrystalline glass. The transparent microcrystalline glass includes the following components in molar percentage: SiO2 35-60%, Al2O3 8-22%, Na2O 10-25%, Li2O 1-9%, P2O5 0.5-3%, ZrO2 0.5-3.5%, TiO2 0-0.5%, MgO 0-3%, B2O3 0-3%, K2O 0-1%, CaO 0-2%, SnO2 0-0.3%; 0.8≤Al2O3 / Na2O≤1.2, 2%≤P2O5+ZrO2+TiO2≤7%; the main crystal forms include triclinic nepheline, sodium nepheline and β-quartz solid solution; the longest dimension of the grains meets specific conditions, the optical and mechanical properties are good, and the glass can be used to prepare protective cover plates for display screens of consumer electronic products.

Description

Technical Field

[0001] The present invention relates to the technical field of microcrystalline glass, and in particular to transparent microcrystalline glass, chemically strengthened microcrystalline glass, and preparation methods and applications thereof. Background Art

[0002] Glass-ceramics are typically produced by adding a certain amount of nucleating agents, such as ZrO2, P2O5, HfO2, and TiO2, to a base glass. The glass-ceramics are then held at a certain temperature for a period of time, inducing crystallization through the nucleating agents. The production of glass-ceramics typically requires heat treatment of the base glass to provide energy for crystal growth. The transformation from base glass to glass-ceramics is a continuous, non-uniform process involving both heat absorption and heat release. By varying the heat treatment temperature and holding time, glass-ceramics with varying crystallization states can be produced.

[0003] As research on glass-ceramics continues to deepen, the need to obtain glass-ceramics with excellent performance in various fields often requires the addition of other oxides, such as alkali metal oxides, alkaline earth metal oxides, and rare earth elements, to the base glass system. This makes the composition of the base glass more complex, resulting in the precipitation of multiple crystals rather than a single crystal during the crystallization process. In order for the glass-ceramics to meet the optical and mechanical properties required for screen cover glass for consumer electronic devices, the common practice is to control the crystal form of the glass-ceramics to a LAS system crystal form with lithium as one of the main elements, such as lithium silicate, petalite, and β-spodumene. At the same time, to enhance the strength of the glass-ceramics, it is also necessary to contain lithium ions in the remaining glass phase of the glass-ceramics for deep ion exchange chemical strengthening. This results in a high lithium content in the glass-ceramics components. When producing LAS system glass-ceramics, a large amount of lithium carbonate is required, which is relatively expensive.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] Based on the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide transparent microcrystalline glass, chemically strengthened microcrystalline glass and preparation methods and applications thereof, aiming to solve the problem that the existing LAS system microcrystalline glass contains a large amount of lithium elements and is relatively expensive.

[0006] The technical solutions of the present invention are as follows:

[0007] A first aspect of the present invention provides a transparent glass-ceramic, wherein the transparent glass-ceramic comprises the following components, calculated in terms of molar percentage of oxides:

[0008] SiO2 35.00%~60.00%, Al2O3 8.00mol%~22.0mol%, Na2O 10.00%~25.00%, Li2O 1.00%~9.00%, P2O5 0.50%~3.00%, ZrO2 0.50%~3.50%, TiO2 0.00%~0.50%, MgO 0.00%~3.00%, B2O3 0.00%~3.00%, K2O 0.00%~1.00%, CaO0.00%~2.00%, SnO2 0.00%~0.30%;

[0009] Among them, 0.80≤Al2O3 / Na2O≤1.20, 2.00%≤P2O5+ZrO2+TiO2≤7.00%;

[0010] The main crystal forms of the transparent glass-ceramics include triclinic nepheline, sodium nepheline and β-quartz solid solution;

[0011] The crystal grains in the transparent glass-ceramics simultaneously meet the following conditions a to e:

[0012] a. The average value of the longest dimension of the grains is 10 to 50 nm;

[0013] b. The proportion of grains with the longest dimension greater than or equal to 5 nm and less than 60 nm to the total number of grains is greater than 5% and less than or equal to 80%;

[0014] c. The proportion of grains with the longest dimension greater than or equal to 60 nm and less than 80 nm to the total number of grains is greater than or equal to 5% and less than or equal to 20%;

[0015] d. The proportion of the number of grains with the longest dimension greater than or equal to 80 nm and less than or equal to 100 nm to the total number of grains is greater than or equal to 0% and less than or equal to 5%;

[0016] e. The proportion of the number of grains with the longest dimension greater than 100 nm to the total number of grains is 0%.

[0017] Optionally, the proportion of the mass of the crystalline phase in the transparent glass-ceramics to the total mass of the transparent glass-ceramics is greater than or equal to 20% and less than or equal to 80%.

[0018] A second aspect of the present invention provides a method for preparing the transparent glass-ceramics as described above, comprising the following steps:

[0019] Mixing ingredients according to the components of transparent glass-ceramics to obtain a mixed material;

[0020] After the mixture is melted, it is formed and annealed to obtain basic glass;

[0021] The transparent microcrystalline glass is obtained by heat treating the basic glass.

[0022] Optionally, the forming method includes a float process, an overflow down-draw process, a calendaring process or a casting process.

[0023] Optionally, the annealing temperature is 420-480° C., and the annealing time is 6-24 hours.

[0024] Optionally, the heat treatment includes a nucleation treatment and a crystallization treatment.

[0025] Optionally, the temperature required for the nucleation treatment is 520-580° C., and the time required for the nucleation treatment is 240-360 min;

[0026] The temperature required for the crystallization treatment is 600-680° C., and the time required for the crystallization treatment is 15-100 minutes.

[0027] The third aspect of the present invention provides a chemically strengthened microcrystalline glass, wherein the chemically strengthened microcrystalline glass is prepared by ion exchange chemical strengthening of the transparent microcrystalline glass as described above in the present invention and / or the transparent microcrystalline glass prepared by the preparation method as described above in the present invention.

[0028] A fourth aspect of the present invention provides a method for preparing chemically strengthened glass-ceramics, comprising the following steps:

[0029] The transparent microcrystalline glass of the present invention as described above and / or the transparent microcrystalline glass prepared by the preparation method of the present invention as described above is placed in molten salt for a preset time, and is chemically strengthened by ion exchange to obtain the chemically strengthened microcrystalline glass.

[0030] Optionally, the salt in the molten salt includes sodium salt, and the concentration of sodium ions in the molten salt is greater than or equal to 10,000 ppm.

[0031] Optionally, the salt in the molten salt further includes at least one of a potassium salt and a lithium salt; in the molten salt, the concentration of lithium ions is greater than or equal to 0 ppm and less than or equal to 100 ppm, and the concentration of potassium ions is greater than or equal to 0 ppm and less than or equal to 30,000 ppm.

[0032] Optionally, the sodium salt includes at least one of sodium nitrate, sodium sulfate and sodium carbonate.

[0033] Optionally, the potassium salt includes at least one of potassium nitrate, potassium sulfate and potassium carbonate, and the lithium salt includes at least one of lithium nitrate, lithium sulfate and lithium carbonate.

[0034] Optionally, the temperature of the molten salt is 380-550° C., and the preset time is 1-48 hours.

[0035] A fifth aspect of the present invention provides an application of the chemically strengthened microcrystalline glass as described above and / or the chemically strengthened microcrystalline glass prepared by the preparation method as described above in consumer electronic products.

[0036] Optionally, the chemically strengthened glass-ceramics is used to prepare a protective cover plate for a display screen of a consumer electronic product.

[0037] Beneficial effects: The present invention greatly reduces the content of alkali metal lithium in transparent microcrystalline glass, reduces costs, and increases the sodium content, forming a NAS system crystal form with sodium as one of the main contents, that is, a system with sodium pyroxene, triclinic pyroxene and β-quartz solid solution as the main crystal form, and at the same time contains a small amount of lithium ions in the remaining glass phase of the microcrystalline glass for ion exchange. The difference in refractive index between the crystal phase and the remaining glass phase in the NAS system microcrystalline glass is small, so it has excellent optical properties. In addition, by regulating the average size of the grains, the distribution and number ratio of grains of different sizes, the transparent microcrystalline glass can have more excellent optical properties (including parameters such as transmittance, haze and color control LAB value) and mechanical properties, and can be used for protective cover materials of display screens of consumer electronic products. In addition, the chemically strengthened microcrystalline glass obtained by chemically strengthening the transparent microcrystalline glass with specific components and specific grain size distribution provided in the present invention also has excellent optical and mechanical properties, which can fully meet the performance requirements of protective cover glass for consumer electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a surface scanning electron microscope image of the transparent microcrystalline glass in Example 1.

[0039] Figure 2 This is a surface scanning electron microscope image of the transparent microcrystalline glass in Example 2.

[0040] Figure 3 This is a surface scanning electron microscope image of the transparent microcrystalline glass in Comparative Example 1.

[0041] Figure 4 This is a surface scanning electron microscope image of the transparent microcrystalline glass in Comparative Example 2.

[0042] Figure 5 This is a graph showing the transmittance of the transparent glass-ceramics in Example 1, Example 2, Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 3 to light in the wavelength range of 400 nm to 960 nm.

[0043] Figure 6This is the differential scanning calorimetry test curve of the base glass in Example 1.

[0044] Figure 7 1 and 2 are XRD patterns of the transparent glass-ceramics in Example 1, Example 2, Example 4, Comparative Example 1, and Comparative Example 2. DETAILED DESCRIPTION

[0045] The present invention provides transparent glass-ceramics, chemically strengthened glass-ceramics, and their preparation methods and applications. To clarify the objectives, technical solutions, and effects of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0046] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0047] The following are some of the terms used in the present invention:

[0048] Basic glass: refers to glass that has not been subjected to nucleation, crystallization and strengthening treatments.

[0049] Glass-ceramics, also known as glass ceramics, are a type of solid composite material composed of both a glass phase and microcrystals / crystalline forms, produced through the targeted and controlled crystallization of a base glass. The microcrystals here can also be referred to as crystalline forms or crystalline phases.

[0050] Chemically strengthened glass-ceramics are solid composite materials obtained by chemically strengthening glass-ceramics. It should be understood that during high-temperature chemical strengthening, alkali metal ions with large ionic radii (such as potassium and sodium ions) in the salt bath / molten salt / molten salt replace alkali metal ions with smaller ionic radii (such as sodium and lithium ions) in the glass-ceramics, resulting in a volume difference in the exchanged ions and compressive stress on the surface of the glass-ceramics.

[0051] The longest dimension of a grain: For a certain grain, the maximum value of the grain length in each dimension is the longest dimension of the grain.

[0052] Average value of the longest dimension of grains: the average value of the longest lengths of all grains contained in the glass-ceramics.

[0053] Total crystal content: the percentage of the mass of crystals in glass-ceramics to the total mass of glass-ceramics.

[0054] Transmittance (abbreviated as Tr): The ratio of the radiant energy projected and passed through the object to the total radiant energy projected onto the object. In the process of the incident light flux leaving from the illuminated surface or the incident surface of the medium to the other side, the ratio of the radiant energy projected and passed through the object to the total radiant energy projected onto the object is called the transmittance of the object.

[0055] The B value in the color control LAB value is used to characterize the yellow-blue value of the micro-glass material. The optical B value in the present invention is the transmitted light B value. A positive optical B value indicates that the material is blue.

[0056] Haze: The cloudy or turbid appearance of the interior or surface of a transparent or translucent material due to light diffusion, expressed as the percentage of the diffused luminous flux to the luminous flux transmitted through the material. When a beam of parallel light from a standard "c" light source is perpendicularly irradiated onto a transparent or translucent film, sheet, or plate, the percentage of the scattered luminous flux Td, which deviates more than 2.5° from the incident direction due to scattering inside and on the surface of the material, to the luminous flux T2 transmitted through the material is the haze. It is an important parameter for the optical transparency of transparent or translucent materials.

[0057] Single rod static pressure strength: the maximum value of the pressure that the microcrystalline glass can withstand from the extrusion rod, measured in N. When the pressure exceeds this value, the microcrystalline glass will break.

[0058] DOL_0: Depth of the compressive stress layer, also known as the depth of the compressive stress layer, refers to the distance from any surface of the microcrystalline glass to the position close to the surface where the compressive stress is zero.

[0059] CS_50: compressive stress at a depth of 50 μm from the surface of the glass-ceramic.

[0060] Through extensive research, the inventors have discovered that the NAS system crystal form, in which sodium is one of the main elements, can also obtain excellent optical and mechanical properties; at the same time, a small amount of lithium is contained in the remaining glass phase of the microcrystalline glass, and when the microcrystalline glass is chemically strengthened by ion exchange, the mechanical properties of the glass are further improved. In addition, if only the grain size is controlled to be less than 100 nm and one or two of the crystal type and crystal ratio are controlled, it cannot be ensured that the microcrystalline glass can meet the optical performance (including transmittance, haze and B value) requirements and mechanical strength performance requirements required for the cover glass material of the display device, and inappropriate grain size control often has an adverse effect on the mechanical strength of the microcrystalline glass. Therefore, how to ensure the acquisition of a transparent microcrystalline glass with excellent optical and mechanical strength properties and a main crystal form of triclinic pyroxene, sodium pyroxene and β-quartz solid solution is a technical problem that the inventors are committed to solving.

[0061] In response to the above technical problems, the inventors studied the crystal conditions in microcrystalline glass, such as the composition of the crystal form, grain size and grain size distribution in microcrystalline glass, and their relationship with the optical properties and mechanical properties of microcrystalline glass. They then found that for microcrystalline glass with triclinic nepheline, sodium nepheline and β-quartz solid solution as the main crystal forms, controlling the grain size distribution thereof will have a better improvement on the transmittance, haze and mechanical strength of the microcrystalline glass. In particular, microcrystalline glass that meets specific grain distribution requirements can ensure high mechanical strength and excellent optical properties.

[0062] Based on this, an embodiment of the present invention provides a transparent glass-ceramic, wherein the transparent glass-ceramic comprises the following components, calculated by molar percentage of oxides:

[0063] SiO2 35.00%~60.00%, Al2O3 8.00%~22.0%, Na2O 10.00%~25.00%, Li2O1.00%~9.00%, P2O5 0.50%~3.00%, ZrO2 0.50%~3.50%, TiO2 0.00%~0.50%, MgO 0.00%~3.00%, B2O3 0.00%~3.00%, K2O 0.00%~1.00%, CaO 0.00%~2.00%, SnO2 0.00%~0.30%;

[0064] Among them, 0.80≤Al2O3 / Na2O≤1.20 (i.e., the molar percentage ratio of Al2O3 to Na2O is greater than or equal to 0.8 and less than or equal to 1.20), 2.00%≤P2O5+ZrO2+TiO2≤7.00% (i.e., the sum of the molar percentages of P2O5, ZrO2, and TiO2 is greater than or equal to 2.00% and less than or equal to 7.00%);

[0065] The main crystal forms of the transparent glass-ceramics include triclinic nepheline, sodium nepheline and β-quartz solid solution;

[0066] The crystal grains in the transparent glass-ceramics simultaneously meet the following conditions a to e:

[0067] a. The average value of the longest dimension of the grains is 10 to 50 nm (for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or any value in a numerical range consisting of any two of the above values ​​as endpoints);

[0068] b. The proportion of grains with the longest dimension greater than or equal to 5 nm and less than 60 nm to the total number of grains is greater than 5% and less than or equal to 80% (for example, it can be 5.1%, 6%, 10%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, or any value in a numerical range consisting of any two of the above values ​​as endpoints);

[0069] c. The proportion of grains with the longest dimension greater than or equal to 60 nm and less than 80 nm to the total number of grains is greater than or equal to 5% and less than or equal to 20% (for example, it can be 5%, 6%, 10%, 12%, 15%, 18%, 20%, or any value in a range consisting of any two of the above values ​​as endpoints);

[0070] d. The proportion of grains with the longest dimension greater than or equal to 80 nm and less than or equal to 100 nm to the total number of grains is greater than or equal to 0% and less than or equal to 5% (for example, it can be 0%, 1%, 2%, 3%, 4%, 5%, or any value in a range consisting of any two of the above values ​​as endpoints);

[0071] e. The proportion of the number of grains with the longest dimension greater than 100 nm to the total number of grains is 0%.

[0072] In this embodiment, the sum of the ratios of the number of grains of different sizes to the total number of grains is 100%, that is, the sum of the proportions of the number of grains of different sizes is 100%.

[0073] In this embodiment, the content of alkali metal lithium in the transparent microcrystalline glass is greatly reduced to reduce the cost, while the content of sodium is increased to form a NAS system crystal structure with sodium as one of the main elements, that is, sodium nepheline (NaAlSiO4), triclinic nepheline (Na 7.85 Al 7.85 Si 8.15 O 32) and β-quartz solid solution as the main crystal forms, and a small amount of lithium ions is contained in the residual glass phase of the microcrystalline glass for ion exchange. The difference in refractive index between the crystal phase and the residual glass phase in the NAS system microcrystalline glass is small, so it has excellent optical properties. In addition, by regulating the average size of the grains, the distribution and quantity proportion of grains of different sizes, and excluding grains larger than 100nm, the transparent microcrystalline glass can have more excellent optical properties (including parameters such as transmittance, haze and B value in the color control LAB value) and mechanical properties, and can be used for protective cover materials of display screens of consumer electronic products. In addition, the chemically strengthened microcrystalline glass obtained by chemically strengthening the transparent microcrystalline glass with specific components and specific grain size distribution provided in the embodiment of the present invention also has excellent optical and mechanical properties, which can fully meet the performance requirements of protective cover glass for consumer electronic products.

[0074] In addition, the inventors discovered that when a transparent glass-ceramic contains a larger proportion of smaller grains, while the optical properties of the transparent glass-ceramic are good, the mechanical strength cannot reach an optimal level; and when a transparent glass-ceramic contains a larger proportion of larger grains, the optical properties of the transparent glass-ceramic deteriorate. In order to achieve a good balance between the optical and mechanical properties of the transparent glass-ceramic, by regulating the grains in the transparent glass-ceramic to meet the above conditions a to e, it is possible to ensure that the resulting transparent glass-ceramic has excellent optical and mechanical properties (or mechanical strength).

[0075] In the embodiments of the present invention, SiO2, as one of the main network oxide components of the base glass and glass-ceramics, is an important component that forms Si-O tetrahedra in the main body and establishes the network structure. Taking all factors into consideration, the molar content of SiO2 is 35.00% to 60.00%, for example, 35.00%, 40.00%, 45.00%, 50.00%, 55.00%, 60.00%, or any value within a numerical range consisting of any two of the aforementioned values ​​as endpoints.

[0076] Al2O3 is an intermediate oxide in glass formation, significantly improving the thermal stability of base glass and glass-ceramics. Furthermore, since [AlO4] is larger than [SiO4], it provides more space for ion exchange, thus promoting ion exchange. However, excessive Al2O3 content increases the viscosity of the glass, hindering melting. Taking all factors into consideration, the molar content of Al2O3 is between 8.00% and 22.0%, for example, 8.00%, 10.00%, 15.00%, 18.00%, 20.00%, 22.00%, or any other value within a range consisting of any two of the aforementioned values.

[0077] Na2O is an important element involved in chemical strengthening of glass-ceramics by ion exchange. It is also a flux when the base glass is melted at high temperature, which can significantly reduce the melting temperature of the base glass. However, when the molar content of Na2O is higher than 25%, the chemical stability of the glass-ceramics will be significantly reduced. Therefore, after comprehensive consideration, the molar content of Na2O is 10.00% to 25.00% (for example, it can be 10.00%, 12.00%, 15.00%, 18.00%, 20.00%, 22.00%, 25.00%, or any value in a numerical range consisting of any two of the above values ​​as endpoints). This can keep the melting temperature within an appropriate range while ensuring good ion exchange properties.

[0078] K2O can reduce the high-temperature viscosity of the base glass, significantly improving its formability and fluidity at high temperatures, while significantly reducing the incidence of cracks. Adding a small amount of K2O can slow the crystallization behavior that occurs during the molding of micro-ceramics. The molar content of K2O is 0.00% to 1.00%, for example, 0.00%, 0.10%, 0.20%, 0.30%, 0.40%, 0.50%, 0.60%, 0.70%, 0.80%, 0.90%, 1.00%, or any value within a numerical range consisting of any two of the aforementioned values ​​as endpoints.

[0079] Li2O is an oxide with high alkali metal activity and is an external oxide of the glass network. As one of the additives to reduce the high temperature viscosity of the base glass, it can significantly improve the high temperature fluidity of the base glass. + The glass-ceramics provided by the present invention can participate in ion exchange to undergo a chemical strengthening reaction, further enhancing the mechanical properties of the glass-ceramics. However, excessive content will increase the cost. Taking all factors into consideration, the molar content of Li2O is 1.00% to 9.00%, for example, 1.00%, 2.00%, 3.00%, 4.00%, 5.00%, 6.00%, 7.00%, 8.00%, 9.00%, or any value within a numerical range consisting of any two of the aforementioned values ​​as endpoints.

[0080] TiO2, ZrO2 and P2O5 are used as nucleating agents, wherein the molar content of TiO2 is 0.00% to 0.50% (for example, it can be 0.00%, 0.10%, 0.20%, 0.30%, 0.40%, 0.50% or any value in the numerical range composed of any two values ​​among the above values ​​as endpoints), and the molar content of ZrO2 is 0.50% to 3.50% (for example, it can be 0.50%, 1.00%, 1.50%, 2.00%, 2.50%, 3.00%, 3.50% or any value in the numerical range composed of any two values ​​among the above values ​​as endpoints). The molar content of P2O5 is 0.50%-3.00% (for example, it can be 0.50%, 1.00%, 1.50%, 2.00%, 2.50%, 3.00%, 3.50% or any value in the numerical range composed of any two of the above numerical values ​​as endpoints), and 2.00%≤ZrO2+TiO2+P2O5≤7.00%. This can improve the crystallization ability of the microcrystalline glass, so that a large number of uniform and fine crystals can be produced in a shorter time of microcrystallization treatment.

[0081] As a component of base glass, the addition of a certain amount of MgO can improve the microcrystallization ability of the crystal. MgO also reduces the difficulty of melting and increases the hardness of the glass. Taking all factors into consideration, the molar content of MgO is 0.00% to 3.00%, for example, 0.00%, 0.50%, 1.00%, 1.50%, 2.00%, 2.50%, 3.00%, or any other value within a range consisting of any two of the aforementioned values ​​as endpoints.

[0082] CaO, as a network-forming oxide in glass, helps reduce the viscosity of the glass, inhibits glass crystallization during glass forming, and improves the low-temperature melting property of the glass. However, excessive CaO can reduce the glass's resistance to devitrification. By adding an appropriate amount of CaO, the viscosity of the glass can be reduced without affecting the glass's crystallization performance. Taking all factors into consideration, the molar content of CaO is 0.00% to 2.00%, for example, 0.00%, 0.10%, 0.50%, 0.80%, 1.00%, 1.20%, 1.50%, 1.80%, 2.00%, or any value within a numerical range consisting of any two of the above values ​​as endpoints.

[0083] B2O3, as a network exosome oxide of the glass, generally fills the voids in the silicon-oxygen tetrahedral framework. Its cation coordination rarely changes, and some properties of its oxide can be considered constant. B2O3 helps to provide a base glass with a low melting temperature. In addition, the addition of B2O3 to the base glass can also improve the damage resistance of the microcrystalline glass. Taking all factors into consideration, the molar content of B2O3 is 0.00% to 3.00%, for example, it can be 0.00%, 0.50%, 1.00%, 1.50%, 2.00%, 2.50%, 3.00%, or any value in a numerical range consisting of any two of the above values ​​as endpoints.

[0084] SnO2 is used as a clarifier. In the present invention, SnO2 can be replaced by at least one of Sb2O3 and NaCl, or by at least two of SnO2, Sb2O3 and NaCl.

[0085] In the embodiment of the present invention, the transparent glass-ceramics has excellent optical properties and mechanical strength, and its thickness can be selected according to actual needs. For example, the thickness of the transparent glass-ceramics is 0.2 to 2.0 mm (specifically, it can be 0.2 m, 0.5 m, 0.7 m, 0.8 m, 0.9 m, 1.0 m, 1.2 m, 1.5 m, 1.6 m, 1.8 m, 2.0 m, or any value in a numerical range consisting of any two of the above values ​​as endpoints). The transparent glass-ceramics has the following properties:

[0086] When the thickness of the transparent glass-ceramics is 0.30 mm ≤ ≤ 1.00 mm, the transmittance of the transparent glass-ceramics for light with a wavelength of 400 to 960 nm is greater than or equal to 85%, and the transmittance of some transparent glass-ceramics can be greater than or equal to 88%.

[0087] When the thickness of the transparent glass-ceramics is 0.30 mm ≤ ≤ 1.00 mm, the B value in the optical color control LAB value of the transparent glass-ceramics satisfies 0.60 ≤ |B value| ≤ 1.20.

[0088] When the thickness of the transparent glass-ceramics is less than or equal to 1.00 mm, the haze of the transparent glass-ceramics is ≤0.15%, wherein the haze of some transparent glass-ceramics may be less than or equal to 0.11%.

[0089] When the thickness of the transparent microcrystalline glass is less than or equal to 0.7 mm, the single-rod static pressure strength of the transparent microcrystalline glass is greater than or equal to 280 N, and the single-rod static pressure strength of some transparent microcrystalline glasses is greater than or equal to 280 N and less than or equal to 600 N.

[0090] In some embodiments, the ratio of the mass of the crystalline phase in the transparent glass-ceramics to the mass of the transparent glass-ceramics is greater than or equal to 20% and less than or equal to 80%, for example, it can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, or any value in a numerical range consisting of any two of the above values ​​as endpoints). When the total content of the crystalline phase of the transparent glass-ceramics is within the above range, it has excellent optical properties and mechanical strength properties, and can be chemically strengthened to obtain a chemically strengthened glass-ceramics that meets the requirements of the screen protection cover of an electronic device through chemical strengthening treatment.

[0091] An embodiment of the present invention further provides a method for preparing the transparent glass-ceramics as described above, comprising the following steps:

[0092] S11. Mixing ingredients according to the components of transparent glass-ceramics to obtain a mixture;

[0093] S12, melting the mixture, forming and annealing it to obtain a base glass;

[0094] S13, heat-treating the base glass to obtain the transparent microcrystalline glass.

[0095] In step S12, in some embodiments, the melting temperature is higher than 1450°C.

[0096] In some embodiments, the forming method includes a float process, an overflow down-draw process, a calendaring process, or a casting process (such as continuous casting).

[0097] In S12, in some embodiments, the annealing temperature is 420-480° C., and the annealing time is 6-24 hours.

[0098] In step S13, in some embodiments, the heat treatment includes a nucleation treatment and a crystallization treatment.

[0099] In some embodiments, the temperature required for the nucleation treatment is 520-580° C. (for example, 520° C., 530° C., 540° C., 550° C., 560° C., 570° C., 580° C., or any value in a numerical range consisting of any two of the above values ​​as endpoints), and the time required for the nucleation treatment is 240-360 min (for example, 240 min, 250 min, 260 min, 270 min, 280 min, 290 min, 300 min, 310 min, 320 min, 330 min, 340 min, 350 min, 360 min, or any value in a numerical range consisting of any two of the above values ​​as endpoints);

[0100] The temperature required for the crystallization treatment is 600-680°C (for example, it can be 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, or any value in a numerical range consisting of any two of the above numerical values ​​as endpoints), and the time required for the crystallization treatment is 15-100 min (for example, it can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, or any value in a numerical range consisting of any two of the above numerical values ​​as endpoints).

[0101] An embodiment of the present invention further provides a chemically strengthened glass-ceramics, wherein the chemically strengthened glass-ceramics is prepared by chemically strengthening the transparent glass-ceramics as described above in the present invention and / or the transparent glass-ceramics prepared by the preparation method as described above in the present invention through ion exchange.

[0102] An embodiment of the present invention further provides a method for preparing chemically strengthened glass-ceramics, which comprises the following steps:

[0103] S21. Place the transparent microcrystalline glass as described above in the present invention and / or the transparent microcrystalline glass prepared by the preparation method as described above in molten salt for a preset time, and obtain the chemically strengthened microcrystalline glass after ion exchange chemical strengthening.

[0104] In the embodiments of the present invention, ion exchange occurs during the chemical strengthening process, imparting specific stress to the transparent glass-ceramics. Therefore, after chemical strengthening, the mechanical properties of the transparent glass-ceramics are appropriately increased, while the strengthening process does not significantly affect the optical properties of the transparent glass-ceramics. Because the transparent glass-ceramics provided by the embodiments of the present invention have excellent optical properties and mechanical strength, the chemically strengthened glass-ceramics obtained by chemically strengthening the transparent glass-ceramics through ion exchange also have excellent optical properties and mechanical strength.

[0105] In addition, a compressive stress layer with a certain depth is formed on the surface of the transparent microcrystalline glass through ion exchange, and at the same time, a tensile stress layer capable of achieving force balance with the compressive stress layer is formed inside the transparent microcrystalline glass, that is, the chemically strengthened microcrystalline glass obtained by ion exchange of the transparent microcrystalline glass has a compressive stress layer and a tensile stress layer. It should be understood that after the ion exchange process, the composition of the stress layer formed may be slightly different from the composition of the microcrystalline glass before the ion exchange (this is because during the ion exchange, the small-radius alkali metal ions (such as Li + Or Na+ ) will be affected by the large radius alkali metal ions (such as Na + or K + ) is replaced by, such as Li in glass-ceramics + and Na in molten salt + Exchange, by Na + Replaced by, or Na in glass-ceramics + K in molten salt + Exchange, K + However, the chemically strengthened glass-ceramics still has the same composition as the transparent glass-ceramics before chemical strengthening in the deep regions where ion exchange has not been performed. In other words, the composition of the tensile stress layer in the chemically strengthened glass-ceramics where ion exchange has not been performed is the same as that of the transparent glass-ceramics.

[0106] The chemically strengthened glass-ceramics provided by the present invention not only has excellent optical properties but also has excellent mechanical properties. The specific properties of the chemically strengthened glass-ceramics are as follows:

[0107] The DOL_0 of the chemically strengthened glass-ceramics is greater than or equal to 0.165T and less than or equal to 0.255T, where T is the thickness of the chemically strengthened glass-ceramics.

[0108] For chemically strengthened glass-ceramics with a thickness of 0.7 mm, its CS_50 is greater than 90 MPa, and the CS_50 of some chemically strengthened glass-ceramics is greater than 90 MPa and less than or equal to 300 MPa.

[0109] In the thickness direction, the degree of ion exchange varies gradually from the surface to the center, while the total exchange amount of Na and K or Li and Na generally does not exceed 1% of the total mass of the transparent glass-ceramic. The difference in ion radius is at the pm (picometer) level, so the expansion effect in the thickness direction is extremely slight, and the thickness can be approximately considered to be unchanged. In other words, the thickness difference before and after chemical strengthening of the glass-ceramic is very small, and the thickness of the chemically strengthened glass-ceramic is approximately equal to the thickness of the transparent glass-ceramic before strengthening. Furthermore, because the surface compressive stress CS, central tensile stress CT, glass thickness T, and ion exchange depth DOL of the chemically strengthened glass-ceramic satisfy the functional relationship CT = (CS × DOL) / (T - 2DOL), the chemically strengthened glass-ceramic has excellent mechanical properties and safety (no self-explosion). The relationship between DOL_0 and glass thickness T satisfies 0.165T ≤ DOL_0 ≤ 0.255T.

[0110] For a 0.7mm thick chemically strengthened glass-ceramics, its DOL_0 is greater than or equal to 115μm and less than or equal to 178μm. When the chemically strengthened glass-ceramics comes into contact with a sharp object, if the compressive stress layer is deep enough, it can better prevent the resulting cracks from entering the tensile stress layer, thereby improving the mechanical strength of the chemically strengthened glass-ceramics.

[0111] For chemically strengthened glass-ceramics with a thickness of 0.70 mm, its Vickers hardness is greater than or equal to 650 kgf / mm 2 , some of the chemically strengthened glass-ceramics have a Vickers hardness of up to 700kgf / mm 2 Up to 800kgf / mm 2 .

[0112] For chemically strengthened microcrystalline glass with a thickness of 0.70 mm, 120-grit sandpaper is used for directional dropping. The average impact energy of the chemically strengthened microcrystalline glass against sandpaper dropping is greater than or equal to 0.3 J. Some chemically strengthened microcrystalline glasses have an average sandpaper drop height of 150 to 200 cm when loaded with 200 g weight, and the corresponding impact energy is 0.30 to 0.40 J.

[0113] In step S21, in some embodiments, the salt in the molten salt includes a sodium salt, and the concentration of sodium ions in the molten salt is greater than or equal to 10,000 ppm.

[0114] In some embodiments, the sodium salt includes at least one of sodium nitrate, sodium sulfate, and sodium carbonate, but is not limited thereto.

[0115] In some embodiments, the salt in the molten salt further includes at least one of a potassium salt and a lithium salt; in the molten salt, the concentration of lithium ions is greater than or equal to 0 ppm and less than or equal to 100 ppm, and the concentration of potassium ions is greater than or equal to 0 ppm and less than or equal to 30,000 ppm.

[0116] In some embodiments, the potassium salt includes at least one of potassium nitrate, potassium sulfate, and potassium carbonate, and the lithium salt includes at least one of lithium nitrate, lithium sulfate, and lithium carbonate, but is not limited thereto.

[0117] In some embodiments, the temperature of the molten salt is 380-550° C. (specifically 400-520° C.), and the preset time is 1-48 hours (specifically 1-12 hours).

[0118] An embodiment of the present invention further provides an application of the chemically strengthened glass-ceramics described above and / or the chemically strengthened glass-ceramics prepared by the preparation method described above in consumer electronic products.

[0119] In some embodiments, the chemically strengthened glass-ceramics is used to prepare a protective cover plate for a display screen of a consumer electronic product.

[0120] In some embodiments, the consumer electronic product includes at least one of a mobile phone, a tablet computer, a smart wearable device, a display (specifically, a vehicle-mounted display), and a television. The electronic device may include a housing and an electronic component partially located within the housing, the housing including a front surface, a rear surface, and side surfaces. The electronic component includes a display device located at or adjacent to the front surface of the housing. The chemically strengthened glass-ceramics provided by the present invention may be applied to the front surface, rear surface, and / or side surface of the housing. The electronic device may also include a covering product covering the front surface of the housing or located on the display device. The chemically strengthened glass-ceramics provided by the present invention may be applied to the covering product.

[0121] The present invention will be further described below with reference to specific examples.

[0122] Table 1. Glass formulations in various embodiments and comparative examples

[0123]

[0124]

[0125] Example 1

[0126] This embodiment provides a method for preparing chemically strengthened glass-ceramics, comprising the following steps:

[0127] (1) According to the components and proportions in Example 1 in Table 1, 1000 g of each raw material powder was weighed, and then placed in a mixer and mixed for 30 minutes to obtain a mixture;

[0128] (2) The mixture was transferred to a platinum crucible, melted at 1580°C for 5 h, poured into a molding mold, and after the casting process, annealed at 450°C for 8 h. After cooling, the basic glass was obtained.

[0129] (3) The above-mentioned base glass is placed in an annealing furnace and kept at 520°C for 240 minutes for nucleation treatment, then heated to 650°C and kept at this temperature for 100 minutes for crystallization treatment, and then cooled to room temperature with the furnace. After shaping, cutting, flat grinding and polishing, transparent microcrystalline glass is obtained.

[0130] (4) The transparent microcrystalline glass was ion-exchanged in a molten salt (99 wt% NaNO3 + 1 wt% KNO3) at 460°C for 8 h to perform chemical strengthening to obtain chemically strengthened microcrystalline glass.

[0131] Example 2

[0132] This embodiment provides a method for preparing chemically strengthened glass-ceramics, which differs from the method in Example 1 only in that: according to the components and proportions in Example 2 in Table 1, 1000 g of each raw material powder is weighed;

[0133] In step (3), the temperature is then raised to 600° C. and kept at this temperature for 100 minutes for crystallization treatment.

[0134] Example 3

[0135] This embodiment provides a method for preparing chemically strengthened glass-ceramics, which differs from the method in Example 1 only in that: according to the components and proportions in Example 3 in Table 1, 1000 g of each raw material powder is weighed;

[0136] In step (3), the temperature is then raised to 620° C. and kept at this temperature for 100 min for crystallization treatment.

[0137] Example 4

[0138] This embodiment provides a method for preparing chemically strengthened glass-ceramics. The only difference from Example 1 is that: according to the components and proportions in Example 4 in Table 1, 1000 g of raw material powders are weighed;

[0139] In step (3), the temperature is then raised to 620° C. and kept at this temperature for 100 min for crystallization treatment.

[0140] Example 5

[0141] This embodiment provides a method for preparing chemically strengthened glass-ceramics. The only difference from Example 1 is that: according to the components and proportions of Example 5 in Table 1, 1000 g of raw material powders are weighed;

[0142] In step (3), the temperature is then raised to 630° C. and kept at this temperature for 100 min for crystallization treatment.

[0143] Example 6

[0144] This embodiment provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions of Example 6 in Table 1, 1000 g of raw material powders are weighed;

[0145] In step (3), the temperature is then raised to 630° C. and kept at this temperature for 100 min for crystallization treatment.

[0146] Comparative Example 1

[0147] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions in Comparative Example 1 in Table 1, a total of 1000 g of raw material powders are weighed;

[0148] In step (3), the temperature is kept at 528°C for 240 minutes for nucleation treatment, and then the temperature is increased to 610°C and kept at this temperature for 100 minutes for crystallization treatment.

[0149] Comparative Example 2

[0150] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The only difference from Example 1 is that: according to the components and proportions in Comparative Example 2 in Table 1, 1000 g of raw material powders are weighed;

[0151] In step (3), the temperature is then raised to 625° C. and kept at this temperature for 100 min for crystallization treatment.

[0152] Comparative Example 3

[0153] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions in Comparative Example 3 in Table 1, 1000 g of raw material powders are weighed;

[0154] In step (3), the temperature is then raised to 660° C. and kept at this temperature for 100 min for crystallization treatment.

[0155] Comparative Example 4

[0156] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions in Comparative Example 4 in Table 1, 1000 g of raw material powders are weighed;

[0157] In step (3), the temperature is kept at 550° C. for 240 min for nucleation treatment, and then the temperature is raised to 620° C. and kept at this temperature for 100 min for crystallization treatment.

[0158] Comparative Example 5

[0159] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions in Comparative Example 5 in Table 1, 1000 g of raw material powders are weighed;

[0160] In step (3), the temperature is then raised to 680° C. and kept at this temperature for 100 min for crystallization treatment.

[0161] Comparative Example 6

[0162] This comparative example provides a method for preparing chemically strengthened glass-ceramics. The difference from Example 1 is that: according to the components and proportions in Comparative Example 6 in Table 1, 1000 g of raw material powders are weighed;

[0163] In step (3), the temperature is kept at 552° C. for 240 min for nucleation treatment, and then the temperature is raised to 670° C. and kept at this temperature for 100 min for crystallization treatment.

[0164] The transparent glass-ceramics and the corresponding chemically strengthened glass-ceramics in each embodiment and comparative example were tested:

[0165] (1) Testing of grain size and its distribution

[0166] A transparent glass-ceramic polished sheet with a length, width and thickness of 10 mm × 10 mm × 0.85 mm was selected as the test sample.

[0167] Selected transparent glass-ceramic polished wafers were immersed in a 5wt% hydrofluoric acid solution (i.e., hydrofluoric acid aqueous solution) at 20°C for 40 seconds. The wafers were then ultrasonically cleaned and dried. After immersion and etching in the hydrofluoric acid solution, the glass phase on the surface of the wafers was removed, leaving the grains clearly visible. The dried wafers were then sprayed with gold and photographed using a JEOL cold field emission scanning electron microscope (SEM), model JSM-7500F, to obtain surface morphologies of the wafers with clear grain boundaries. The photographs were taken at a magnification of 50kx.

[0168] The surface morphology images were processed using the particle size distribution software ImageJ. Grains within a 1000 nm × 1000 nm region of the surface morphology image were selected as samples and marked by their longest length. The software automatically recorded the longest length of each grain within the region and defined the average of the longest lengths of all recorded grains within the region as the average grain size (i.e., the average of the longest lengths of the grains).

[0169] (2) Crystal form test

[0170] The transparent glass-ceramics sheet is ground into glass fine powder with a grinding machine. The maximum size of the fine powder particles is less than 75μm. Then, an X-ray diffractometer (Shimadzu XRD-6100) is used to test it under the conditions of a diffraction angle range of 2θ=10°-80°, a scanning speed of 6° / min, an operating voltage of 40kV, and an operating current of 30mA to obtain a diffraction peak curve. The diffraction data is then analyzed using professional processing software Jade software (Gsas software, Fullprof software, or Maud software can also be used) to analyze the crystal form of the crystals contained in the glass-ceramics. At the same time, the XRD diffraction peak curve is fitted to obtain the total content of the crystalline phase in the glass-ceramics. Specifically, the method for obtaining the total content of the crystalline phase is as follows: the X-ray diffractometer test result file (RAW format) is imported into the X-ray diffraction data Rietveld refinement software Jade software, and fitting and calculation are performed to obtain the total content of the crystalline phase in the glass-ceramics. The ratio of the fitted crystalline phase peak area to the fitted total peak area is the total crystal content, also known as crystallinity.

[0171] (3) Optical performance testing (including testing of parameters such as transmittance, haze and LAB value of transparent microcrystalline glass)

[0172] A 50 mm x 50 mm x 0.65 mm transparent glass-ceramic polished wafer was cleaned in an ultrasonic cleaner. The cleaning conditions were as follows: 5 min, deionized water, 50°C, and 40 kHz.

[0173] After cleaning, the transmittance and optical B value of the polished transparent micro-ceramic glass were tested according to the national standard GB / T 7962.12-2010, "Test methods for colorless optical glass - Part 12: Spectral transmittance." The haze was tested using a haze meter. The haze meter used in the present invention was a Konica Minolta CM-3600A spectrophotometer from Japan. The light receiving optical system was transmission, the spectroscopic mode was a diffraction grating, the wavelength range was 360-960 nm, the wavelength spacing was 10 nm, and the illumination light source was a pulsed xenon lamp X4. The instrument was placed in an ambient temperature of 24°C and an air humidity of 40%.

[0174] (4) Single rod static pressure strength test (also known as extrusion pressure test)

[0175] Place the transparent glass-ceramic polished sheet to be tested with a length, width and thickness of 50mm×50mm×0.7mm on the bottom ring of the tensile testing machine (LT_850A), start the test software, and set the moving speed of the extrusion rod (rod diameter is 8mm, indenter arc radius is 10mm) to 10mm / min. Click to start the test, and the extrusion rod will apply force to the center of the transparent glass-ceramic sheet to be tested at the set moving speed until the transparent glass-ceramic cracks and breaks. The test software will automatically read the force (N) when the transparent glass-ceramic breaks as the test result. Take 10 transparent glass-ceramic samples in the same state for testing, and take the average value of the test results as the single-rod static pressure strength of the glass-ceramic sample.

[0176] (5) Stress test

[0177] Using a Japanese Orihara stress meter SLP-2000, the compressive stress depth (DOL_0) and compressive stress at a depth of 50 μm (C5_50) of chemically strengthened glass-ceramics were tested in accordance with the national standard GB-T 18144-2008, "Glass Stress Test Method." The stress test was conducted on a chemically strengthened glass-ceramic sample measuring 50 mm x 50 mm x 0.7 mm. The light source wavelength was 518 nm, the photoelastic coefficient (SOC) was 25.0 (nm / cm) / MPa, the refractive index was 1.54, and the exposure time was 300 usec. To test CS_50 and DOL_0, a conductive liquid with a refractive index of 1.51 was dripped onto the stress meter. The chemically strengthened glass-ceramic sample was then wiped clean and placed on the test path to measure the values. Photoelasticity refers to the phenomenon of anisotropy and birefringence in transparent materials when subjected to stress. The value of the internal residual stress (MPa) of the material can be obtained by measuring the photoelastic coefficient and birefringence.

[0178] (6) Vickers hardness test

[0179] The Vickers hardness of chemically strengthened glass-ceramics was tested using a digital low-load Vickers hardness tester VTD405 (Beijing Wowei Technology Co., Ltd.) in accordance with the national standard GB / T37900-2019, "Test method for hardness and fracture toughness of ultra-thin glass - Low-load Vickers hardness indentation method." The Vickers hardness test was performed on chemically strengthened glass-ceramics samples measuring 50 mm x 50 mm x 0.7 mm.

[0180] (7) Drop test

[0181] Average Sandpaper Drop Height: This refers to the ratio of the sum of the sandpaper drop heights measured for multiple identical chemically strengthened glass-ceramics samples to the total number of chemically strengthened glass-ceramics samples. This is used to characterize the drop resistance of chemically strengthened glass-ceramics. At least 10 identical chemically strengthened glass-ceramics samples should be tested each time to obtain the average sandpaper drop height.

[0182] The test method for the sandpaper drop resistance of each chemically strengthened glass-ceramic sample is as follows:

[0183] Step 1: Stick 120-grit sandpaper on the bottom surface of a 160g model machine and place the model machine on a green figure LT-SKDL-CD drop machine.

[0184] Step 2: Place a chemically strengthened glass-ceramic sample to be tested, measuring 50mm x 50mm x 0.7mm, directly below the model machine, with the sample facing the sandpaper. Drop the model machine from a specific drop height, impacting the chemically strengthened glass-ceramic sample directly below it. If the chemically strengthened glass-ceramic sample does not break, increase the drop height of the model machine according to a specific pattern. For example, start at a drop height of 40cm and drop the glass-ceramic sample once. If it does not break, increase the drop height by 10cm each time until the chemically strengthened glass-ceramic sample breaks.

[0185] Step 3: The last drop height of the chemically strengthened glass-ceramic sample when it breaks is recorded as the sandpaper drop height. For example, if the drop height when it breaks is 100 cm, the sandpaper drop height of the sample is 90 cm.

[0186] The surface scanning electron microscope image of the transparent glass-ceramics prepared in Example 1 is as follows: Figure 1 As shown, the surface scanning electron microscope image of the transparent microcrystalline glass in Example 2 is as follows Figure 2 As shown, the surface scanning electron microscope image of the transparent microcrystalline glass in Comparative Example 1 is as follows Figure 3 As shown, the surface scanning electron microscope image of the transparent microcrystalline glass in Comparative Example 2 is as follows Figure 4 shown.

[0187] The transmittance of the transparent glass-ceramics in Example 1, Example 2, Example 4, Comparative Example 1, Comparative Example 2 and Comparative Example 3 to light in the wavelength range of 400nm to 960nm is shown in the figure below: Figure 5 As shown, it can be seen that the transmittance of the transparent microcrystalline glass in Example 1, Example 2, and Example 4 to light in the 400nm to 960nm band is much higher than that of the transparent microcrystalline glass in Comparative Example 2 and Comparative Example 3.

[0188] The transparent glass-ceramics in Comparative Examples 1, 2 and 3; the differential scanning calorimetry test curves of the base glass in Example 1 are as follows: Figure 6 As shown, it has exothermic peaks at 645.6°C and 685°C.

[0189] The XRD patterns of the transparent glass-ceramics in Example 1, Example 2, Example 4, Comparative Example 1 and Comparative Example 2 are as follows: Figure 7 shown.

[0190] The proportion of grains of different sizes in the transparent microcrystalline glass in each embodiment and comparative example, the content of the crystal phase and the crystal form are shown in Table 2, and the optical properties and mechanical properties are shown in Table 3; the mechanical properties of the chemically strengthened microcrystalline glass are shown in Table 4.

[0191] Table 2. Ratio of the number of grains of different sizes in the transparent glass-ceramics and the content and crystal form of the crystalline phase in each embodiment and comparative example

[0192]

[0193]

[0194] It can be seen that the crystals in the comparative example are different from the crystals in the examples of the present invention in terms of crystal form.

[0195] Table 3. Optical properties and mechanical strength of transparent glass-ceramics in various examples and comparative examples

[0196]

[0197] Table 4 Mechanical properties of chemically strengthened glass-ceramics in various examples and comparative examples

[0198]

[0199]

[0200] From the above results, it can be seen that the transparent glass-ceramics and chemically strengthened glass-ceramics prepared in the embodiments of the present invention have excellent optical and mechanical properties.

[0201] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A transparent glass-ceramic, characterized in that: Calculated by molar percentage of oxides, the transparent glass-ceramics includes the following components: SiO2 35.00%~60.00%, Al2O3 8.00%~22.0%, Na2O 10.00%~25.00%, Li2O1.00%~9.00%, P2O5 0.50%~3.00%, ZrO2 0.50%~3.50%, TiO2 0.00%~0.50%, MgO0.00%~3.00%, B2O3 0.00%~3.00%, K2O 0.00%~1.00%, CaO 0.00%~2.00%, SnO20.00%~0.30%; Among them, 0.80≤Al2O3 / Na2O≤1.20, 2.00%≤P2O5+ZrO2+TiO2≤7.00%; The main crystal forms of the transparent glass-ceramics include triclinic nepheline, sodium nepheline and β-quartz solid solution; The crystal grains in the transparent glass-ceramics simultaneously meet the following conditions a to e: a. The average value of the longest dimension of the grains is 10 to 50 nm; b. The proportion of grains with the longest dimension greater than or equal to 5 nm and less than 60 nm to the total number of grains is greater than 5% and less than or equal to 80%; c. The proportion of grains with the longest dimension greater than or equal to 60 nm and less than 80 nm to the total number of grains is greater than or equal to 5% and less than or equal to 20%; d. The proportion of the number of grains with the longest dimension greater than or equal to 80 nm and less than or equal to 100 nm to the total number of grains is greater than or equal to 0% and less than or equal to 5%; e. The proportion of the number of grains with the longest dimension greater than 100 nm to the total number of grains is 0%; The sum of the ratios of the number of grains of different sizes to the total number of grains is 100%.

2. The transparent glass-ceramics according to claim 1, characterized in that: The proportion of the mass of the crystalline phase in the transparent micro-ceramics to the total mass of the transparent micro-ceramics is greater than or equal to 20% and less than or equal to 80%.

3. A method for preparing the transparent glass-ceramics according to claim 1, characterized in that: The steps include: Mixing ingredients according to the components of transparent glass-ceramics to obtain a mixed material; After the mixture is melted, it is formed and annealed to obtain basic glass; The transparent microcrystalline glass is obtained by heat treating the basic glass.

4. The preparation method according to claim 3, characterized in that The forming method includes float process, overflow down-draw process, calendaring process or casting process.

5. The preparation method according to claim 3, characterized in that The annealing temperature is 420-480° C., and the annealing time is 6-24 hours.

6. The preparation method according to claim 3, characterized in that The heat treatment includes a nucleation treatment and a crystallization treatment.

7. The preparation method according to claim 6, characterized in that The temperature required for the nucleation treatment is 520-580°C, and the time required for the nucleation treatment is 240-360 minutes; The temperature required for the crystallization treatment is 600-680° C., and the time required for the crystallization treatment is 15-100 minutes.

8. A chemically strengthened glass-ceramic, characterized in that: The chemically strengthened glass-ceramics is prepared by subjecting the transparent glass-ceramics described in any one of claims 1 to 2 and / or the transparent glass-ceramics prepared by the preparation method described in any one of claims 3 to 7 to ion exchange chemical strengthening.

9. A method for preparing chemically strengthened glass-ceramics, characterized in that: The steps include: The transparent microcrystalline glass described in any one of claims 1-2 and / or the transparent microcrystalline glass prepared by the preparation method described in any one of claims 3-7 is placed in molten salt for a preset time, and after ion exchange chemical strengthening, the chemically strengthened microcrystalline glass is obtained.

10. The preparation method according to claim 9, characterized in that The salt in the molten salt includes sodium salt, and the concentration of sodium ions in the molten salt is greater than or equal to 10000 ppm.

11. The preparation method according to claim 10, characterized in that: The salt in the molten salt further includes at least one of a potassium salt and a lithium salt; in the molten salt, the concentration of lithium ions is greater than or equal to 0 ppm and less than or equal to 100 ppm, and the concentration of potassium ions is greater than or equal to 0 ppm and less than or equal to 30,000 ppm.

12. The preparation method according to claim 10, characterized in that The sodium salt includes at least one of sodium nitrate, sodium sulfate and sodium carbonate.

13. The preparation method according to claim 11, characterized in that The potassium salt includes at least one of potassium nitrate, potassium sulfate and potassium carbonate, and the lithium salt includes at least one of lithium nitrate, lithium sulfate and lithium carbonate.

14. The preparation method according to claim 9, characterized in that The temperature of the molten salt is 380-550° C., and the preset time is 1-48 hours.

15. Use of the chemically strengthened glass-ceramics according to claim 8 and / or the chemically strengthened glass-ceramics prepared by the preparation method according to any one of claims 9 to 14 in consumer electronic products.

16. The use according to claim 15, characterized in that The chemically strengthened glass-ceramics is used to prepare a protective cover plate for a display screen of a consumer electronic product.

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