Transparent glass ceramic, chemically strengthened glass ceramic and preparation method and application thereof

Abstract

The invention discloses transparent microcrystalline glass, chemically strengthened microcrystalline glass and a preparation method and application thereof, and relates to the technical field of microcrystalline glass. The transparent microcrystalline glass is prepared from the following components in percentage by mole: 35 to 60 percent of SiO2, 8 to 22 percent of Al2O3, 10 to 25 percent of Na2O, 1 to 9 percent of Li2O, 0.5 to 3 percent of P2O5, 0.5 to 3.5 percent of ZrO2, 20 to 0.5 percent of TiO2, 0 to 3 percent of MgO, 0 to 3 percent of B2O3, 0 to 1 percent of K2O, 0 to 2 percent of CaO and 0 to 0.3 percent of SnO2. 0.8 < = Al2O3 / Na2O < = 1.2, 2% < = P2O5 + ZrO2 + TiO2 < = 7%; the main crystal form comprises triclinic nepheline, sodium nepheline and a beta quartz solid solution; the longest size of the crystal grains meets specific conditions, and the crystal grains are good in optical and mechanical properties and can be used for preparing consumer electronic product display screen protective cover plates.

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 usually made by adding a certain amount of nucleating agent, such as ZrO2, P2O5, HfO2, TiO2, etc., to the base glass, and then keeping it at a certain temperature for a period of time to induce crystallization of the glass-ceramics through the nucleating agent, thereby obtaining the target glass-ceramics. The acquisition of glass-ceramics usually requires heat treatment of the base glass so that the crystal growth can obtain energy. The transformation from base glass to glass-ceramics is a continuous non-uniform change process, and there are heat absorption and heat release phenomena in this process. By changing the heat treatment temperature and holding time, glass-ceramics with different crystallization states can be obtained.

[0003] As people's research on microcrystalline glass continues to deepen, in order to obtain microcrystalline glass with excellent performance in various fields, it is often necessary to add some other oxides to the basic glass system, such as alkali metal oxides, alkaline earth metal oxides, rare earth elements, etc., which makes the composition of the basic glass more complex, resulting in the precipitation of not a single crystal but multiple crystals during the crystallization process of the basic glass. In order to make the microcrystalline glass material meet the optical and mechanical properties required by the screen cover protective glass of consumer electronic devices, the usual practice is to control the crystal form of the crystal in the microcrystalline glass to the LAS system crystal form with lithium as one of the main elements, such as lithium silicate, petalite, β-spodumene and other crystal forms. At the same time, in order to enhance the strength of the microcrystalline glass, it is also necessary to contain lithium ions that can be deeply ion exchanged and chemically strengthened in the remaining glass phase of the microcrystalline glass, so that the components of the microcrystalline glass contain a high content of lithium. When making LAS system microcrystalline glass, a large amount of lithium carbonate is required, which is costly.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] Based on the above-mentioned deficiencies of 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 has a high cost.

[0006] The technical solution of the present invention is as follows:

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

[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 microcrystalline glass 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 the number of grains with the longest dimension of 5 nm or more 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 the number of grains with the longest dimension of grains 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 of the grains being 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 mass of the crystalline phase in the transparent glass-ceramics accounts for a proportion of the total mass of the transparent glass-ceramics that 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 microcrystalline glass 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 molded 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 calendering 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 glass-ceramics, wherein the chemically strengthened glass-ceramics is prepared by ion exchange chemical strengthening of 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.

[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 after ion exchange chemical strengthening, the chemically strengthened microcrystalline glass is obtained.

[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 10000 ppm.

[0031] Optionally, the salt in the molten salt also 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 30000 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 glass-ceramics as described above and / or the chemically strengthened glass-ceramics 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 content of sodium, forming a NAS system crystal with sodium as one of the main contents, that is, a system with sodium nepheline, triclinic nepheline and β-quartz solid solution as the main crystal, and a small amount of lithium ions are contained 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 proportion 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 consumer electronic product display screen protection cover materials. 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 properties 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 400nm to 960nm.

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

[0044] Figure 7 1 and 2. The XRD spectra 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 microcrystalline glass, chemically strengthened microcrystalline glass and preparation methods and applications thereof. To make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used 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 is an explanation of some of the terms involved in the present invention:

[0048] Basic glass: refers to glass that has not been treated with nucleation, crystallization or strengthening.

[0049] Glass-ceramics: also known as glass ceramics, is a type of solid composite material that contains both glass phase and microcrystalline / crystal form, which is prepared by targeted controlled crystallization of base glass. The microcrystalline form here can also be called crystalline form or crystal phase.

[0050] Chemically strengthened glass-ceramics: It is a solid composite material obtained after chemical strengthening treatment of glass-ceramics. It should be understood that during high-temperature chemical strengthening treatment, alkali metal ions with large ionic radius (such as potassium ions and sodium ions) in the salt bath / molten salt / molten salt will replace alkali metal ions with small ionic radius (such as sodium ions and lithium ions) in the glass-ceramics, thereby generating an exchange ion volume difference and generating 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 length of all grains contained in the microcrystalline glass.

[0053] Total crystal content: the percentage of crystal mass 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 an 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 microcrystalline glass material. The optical B value in the present invention is the transmitted light B value, and 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 light flux to the light flux transmitted through the material. A beam of parallel light from a standard "c" light source is vertically irradiated onto a transparent or translucent film, sheet, or plate. Due to scattering inside and on the surface of the material, part of the parallel light deviates from the incident direction by more than 2.5°. The percentage of the scattered light flux Td to the light flux T2 transmitted through the material is the haze, which is an important parameter for the optical transparency of transparent or translucent materials.

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

[0058] DOL_0: Depth of compressive stress layer, also known as depth of compressive stress layer, refers to the distance from any surface of microcrystalline glass to the position where the compressive stress near the surface 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 by controlling the grain size to be less than 100nm and controlling one or two of the crystal type and crystal ratio, it cannot ensure 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 nepheline, sodium nepheline, 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 more excellent 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 microcrystalline glass, wherein, in terms of the molar percentage of oxides, the transparent microcrystalline includes the following components:

[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 microcrystalline glass include triclinic nepheline, sodium nepheline and β-quartz solid solution;

[0066] The crystal grains in the transparent glass-ceramics simultaneously satisfy 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 may 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 the number of grains with the longest dimension of 5 nm or more 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 the number of grains with the longest dimension of grains being 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 may be 5%, 6%, 10%, 12%, 15%, 18%, 20% or any value in a numerical range consisting of any two of the above values ​​as endpoints);

[0070] d. The ratio of the number of grains with the longest dimension of the grains being 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 numerical range consisting of any two of the above numerical 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, and the content of sodium is increased to form a NAS system crystal 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 are 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 LAB value of color control) and mechanical properties, and can be used for protective cover materials for 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 embodiments 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 found that when the proportion of smaller grains in the transparent glass-ceramics is relatively large, the optical properties of the transparent glass-ceramics are good, but the mechanical strength cannot reach a better level; and when the proportion of larger grains in the transparent glass-ceramics is relatively large, the optical properties of the transparent glass-ceramics will deteriorate. In order to achieve a better balance between the optical properties and mechanical properties of the transparent glass-ceramics, by regulating the grains in the transparent glass-ceramics to meet the above conditions a to e, it can be ensured that the obtained transparent glass-ceramics have excellent optical properties and mechanical properties (or mechanical strength).

[0075] In the embodiment of the present invention, SiO2 is one of the main components of the network oxide of the base glass and the microcrystalline glass, and is one of the important components that constitute the Si-O tetrahedron in the main body and form the network structure. Taking all factors into consideration, the molar content of SiO2 is 35.00% to 60.00%, for example, it can be 35.00%, 40.00%, 45.00%, 50.00%, 55.00%, 60.00% or any value in the numerical range consisting of any two of the above numerical values ​​as endpoints.

[0076] Al2O3 is an intermediate oxide in the formation of glass, which can significantly improve the thermal stability of basic glass and microcrystalline glass. At the same time, since [AlO4] has a larger volume than [SiO4], it can provide more space for ion exchange. Therefore, Al2O3 can promote ion exchange, but too high Al2O3 will increase the viscosity of the glass, which is not conducive to melting. Taking all factors into consideration, the molar content of Al2O3 is 8.00% to 22.0%, for example, it can be 8.00%, 10.00%, 15.00%, 18.00%, 20.00%, 22.00% or any value in the numerical range consisting of any two of the above numerical values ​​as endpoints.

[0077] Na2O is an important element that participates in the 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 the numerical range composed of any two of the above values ​​as endpoints), so that the melting temperature can be kept within a suitable range and good ion exchange characteristics can be guaranteed.

[0078] K2O can reduce the high temperature viscosity of the base glass, significantly improve the formability and fluidity of the base glass at high temperature, and significantly reduce the crack incidence. Among them, a small amount of K2O can slow down the crystallization behavior during the molding of microcrystalline glass. Considering that the molar content of K2O is 0.00% to 1.00%, for example, it can be 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 in the numerical range composed of any two of the above numerical 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. + In the microcrystalline glass provided by the present invention, ion exchange can be involved in chemical strengthening reaction to further enhance the mechanical properties of the microcrystalline glass, but excessive content will lead to increased costs. Comprehensively considered, the molar content of Li2O is 1.00% to 9.00%, for example, it can be 1.00%, 2.00%, 3.00%, 4.00%, 5.00%, 6.00%, 7.00%, 8.00%, 9.00% or any value in the numerical range composed of any two of the above numerical 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 a numerical range composed of any two of the above numerical 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 of the above numerical 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 values ​​among the above values ​​as endpoints), and 2.00%≤ZrO2+TiO2+P2O5≤7.00%. This can improve the crystallization ability of 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 the basic glass, a certain amount of MgO can improve the microcrystallization ability of the crystal, and MgO also has the effect of reducing the difficulty of melting and improving the hardness of the glass. Taking all factors into consideration, the molar content of MgO 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 the numerical range consisting of any two of the above numerical values ​​as endpoints.

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

[0083] B2O3, as a network exosome oxide of glass, is generally filled in the voids of 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, adding B2O3 to the base glass can also improve the damage resistance of 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 the numerical range consisting of any two of the above numerical 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 SnO2 can be replaced by at least two of SnO2, Sb2O3 and NaCl.

[0085] In the embodiment of the present invention, the transparent microcrystalline glass has excellent optical properties and mechanical strength, and its thickness can be selected according to actual needs. For example, the thickness of the transparent microcrystalline glass is 0.2-2.0 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), and the transparent microcrystalline glass has the following properties:

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

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

[0088] When the thickness of the transparent microcrystalline glass is less than or equal to 1.00 mm, the haze of the transparent microcrystalline glass is ≤0.15%, wherein the haze of some transparent microcrystalline glasses 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 280N, and some of the transparent microcrystalline glasses have a single-rod static pressure strength greater than or equal to 280N and less than or equal to 600N.

[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] The present invention also provides a method for preparing the transparent glass-ceramics as described above, which comprises the following steps:

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

[0093] S12, melting the mixed material, and then molding and annealing the mixed material to obtain a basic glass;

[0094] S13, obtaining the transparent microcrystalline glass by heat treating the basic 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, it can be 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 numerical values ​​as endpoints), and the time required for the nucleation treatment is 240-360 min (for example, it can be 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 numerical 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 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 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 subjecting the transparent glass-ceramics described above in the present invention and / or the transparent glass-ceramics prepared by the preparation method described above in the present invention to ion exchange chemical strengthening.

[0102] The 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 glass-ceramics as described above in the present invention and / or the transparent glass-ceramics prepared by the preparation method as described above in molten salt for a preset time, and obtain the chemically strengthened glass-ceramics after ion exchange chemical strengthening.

[0104] In the embodiment of the present invention, since ion exchange occurs during the chemical strengthening process, the transparent glass-ceramics is given specific stress. Therefore, after the chemical strengthening treatment, the mechanical properties of the transparent glass-ceramics will be appropriately increased, and the strengthening process will not significantly affect the optical properties of the transparent glass-ceramics. Since the transparent glass-ceramics provided by the embodiment of the present invention has 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 + ) are replaced by, such as Li in glass-ceramics + and Na in molten salt + Exchange, by Na + Replaced by, or Na in glass-ceramics + With K in molten salt + Exchange, K + However, the chemically strengthened glass-ceramics in the deep region where ion exchange has not been performed is still the same as the transparent glass-ceramics before chemical strengthening. That is, 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 changes gradually from the surface to the center, and the total exchange amount of Na and K or Li and Na generally does not exceed 1% of the total mass of the transparent microcrystalline glass, and the difference in ion radius is at the pm (picometer) level, so the expansion effect in the thickness direction is very slight, and it can be approximately considered that the thickness has not changed. That is, the thickness difference before and after chemical strengthening of the microcrystalline glass is very small, and the thickness of the chemically strengthened microcrystalline glass is approximately equal to the thickness of the transparent microcrystalline glass before strengthening. At the same time, since the surface compressive stress CS, the central tensile stress CT, the glass thickness T and the ion exchange depth DOL of the chemically strengthened microcrystalline glass satisfy the functional relationship CT = (CS × DOL) / (T-2DOL), the chemically strengthened microcrystalline glass has excellent mechanical properties and safety (no self-explosion), and the relationship between DOL_0 and the glass thickness T satisfies 0.165T≤DOL_0≤0.255T.

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

[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 chemically strengthened glass-ceramics have a Vickers hardness of up to 700 kgf / mm 2 Up to 800kgf / mm 2 .

[0112] For chemically strengthened microcrystalline glass with a thickness of 0.70 mm, 120-mesh 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 of the chemically strengthened microcrystalline glasses have an average sandpaper drop height of 150 to 200 cm when loaded with a weight of 200 g, 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 10000 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 30000 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 as described above and / or the chemically strengthened glass-ceramics prepared by the preparation method as 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, a display (specifically, a car display), and a television. The electronic device may include a housing and an electronic component partially located in the housing, the housing includes a front surface, a rear surface, and a side surface, the electronic component includes a display device, the display device is located at the front surface of the housing or adjacent to the front surface, and the chemically strengthened microcrystalline glass provided by the present invention can be applied to the front surface and / or the rear surface and / or the 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, and the chemically strengthened microcrystalline glass provided by the present invention can be applied to the covering product.

[0121] The present invention will be further described below by means of specific examples.

[0122] Table 1. Formula of glass 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, weigh 1000 g of each raw material powder, and then place it in a mixer and mix it for 30 minutes to obtain a mixture;

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

[0129] (3) The 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, a transparent microcrystalline glass is obtained.

[0130] (4) The transparent microcrystalline glass is ion exchanged in a molten salt (99wt% NaNO3+1wt% KNO3) at 460°C for 8h 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 is different from the method of embodiment 1 only in that: according to the components and proportions in embodiment 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 maintained for 100 min for crystallization treatment.

[0134] Example 3

[0135] This embodiment provides a method for preparing chemically strengthened glass-ceramics, which is different from the method of embodiment 1 only in that: according to the components and proportions in embodiment 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 maintained for 100 min for crystallization treatment.

[0137] Example 4

[0138] This embodiment provides a method for preparing chemically strengthened glass-ceramics, which is different from the method in Embodiment 1 only in that: according to the components and proportions in Embodiment 4 in Table 1, 1000 g of each raw material powder is weighed;

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

[0140] Example 5

[0141] This embodiment provides a method for preparing chemically strengthened glass-ceramics, which is different from the method in Embodiment 1 only in that: according to the components and proportions in Embodiment 5 in Table 1, 1000 g of each raw material powder is weighed;

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

[0143] Example 6

[0144] This embodiment provides a method for preparing a chemically strengthened glass-ceramics, which is different from the method in the first embodiment only in that: according to the components and proportions in the first embodiment in Table 1, 1000 g of each raw material powder is weighed;

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

[0146] Comparative Example 1

[0147] This comparative example provides a method for preparing a chemically strengthened glass-ceramics, which differs from Example 1 only in that: according to the components and proportions in Comparative Example 1 in Table 1, 1000 g of each raw material powder is 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 for 100 minutes for crystallization treatment.

[0149] Comparative Example 2

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

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

[0152] Comparative Example 3

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

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

[0155] Comparative Example 4

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

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

[0158] Comparative Example 5

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

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

[0161] Comparative Example 6

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

[0163] In step (3), the temperature is kept at 552°C for 240 minutes for nucleation treatment, and then the temperature is increased to 670°C and kept for 100 minutes 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 microcrystalline glass polished sheet with a length, width and thickness of 10 mm × 10 mm × 0.85 mm was selected as the test sample.

[0167] The selected transparent microcrystalline glass polishing sheet was soaked in a 5wt% hydrofluoric acid solution (i.e., hydrofluoric acid aqueous solution) at 20°C for 40s, and then the transparent microcrystalline glass polishing sheet was taken out, ultrasonically cleaned, and dried. After being soaked and corroded in the hydrofluoric acid solution, the glass phase on the surface of the transparent microcrystalline glass polishing sheet will be removed, and the grains will be clearly visible. After that, gold was sprayed on the surface of the dried transparent microcrystalline glass polishing sheet, and a JEOL cold field emission scanning electron microscope (SEM) model JSM-7500F was used to obtain the surface morphology of the transparent microcrystalline glass polishing sheet with clear grain boundaries, and the magnification of the photograph after shooting was 50kx.

[0168] The surface morphology images taken were processed using the particle size distribution software ImageJ. The grains in the 1000nm×1000nm area of ​​the surface morphology image were selected as samples, and the longest length of the grains was used as a mark. The software automatically recorded the longest length of each grain in the area, and defined the average value of the longest length of all recorded grains in the area as the average grain size (i.e., the average value of the longest length of the grains).

[0169] (2) Crystal form test

[0170] The transparent microcrystalline glass sheet is ground into glass fine powder by a grinding machine, and the maximum size of the particles of the fine powder 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, a working voltage of 40kV, and a working current of 30mA to obtain a diffraction peak curve. The diffraction data is then analyzed using the 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 microcrystalline glass, and the XRD diffraction peak curve is fitted to obtain the total content of the crystal phase in the microcrystalline glass. Specifically, the method for obtaining the total content of the crystal 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 crystal phase in the microcrystalline glass. 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 transmittance, haze, LAB value and other parameters of transparent microcrystalline glass)

[0172] A transparent microcrystalline glass polished sheet with a length, width and thickness of 50 mm×50 mm×0.65 mm was cleaned in an ultrasonic cleaning machine. The cleaning conditions were as follows: the cleaning time was 5 min, the cleaning agent used was deionized water, the cleaning temperature was 50°C, and the cleaning frequency was 40 kHz.

[0173] After cleaning, the test was performed with reference to the test method of the national standard GB / T 7962.12-2010 "Colorless Optical Glass Test Method Part 12: Spectral Transmittance", and the transmittance and optical B value of the transparent microcrystalline glass polished sheet were tested. The haze was tested using a haze meter, and the haze meter used in the present invention was a Japanese Konica Minolta spectrophotometer CM-3600A, the light receiving optical system was transmission, the light splitting mode was a diffraction grating, the wavelength range was 360 to 960 nm, the wavelength spacing was 10 nm, the illumination light source was a pulse xenon lamp X4, the ambient temperature of the instrument was 24°C, and the air humidity was 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 the stress meter SLP-2000 of Japan Orihara, the test was carried out with reference to the test method of the national standard GB-T 18144-2008 "Glass Stress Test Method", and the compressive stress layer depth (DOL_0) and the compressive stress at a depth of 50μm (C5_50) of the chemically strengthened microcrystalline glass were tested. When the present invention performs stress testing, a chemically strengthened microcrystalline glass sample with a length, width and thickness of 50mm×50mm×0.7mm is tested. During the test, the selected light source wavelength is 518nm, the photoelastic coefficient (SOC) = 25.0 (nm / cm) / MPa, the refractive index = 1.54, and the exposure time is 300usec. When testing CS_50 and DOL_0, it is necessary to drip a conductive liquid with a refractive index of 1.51 on the stress meter, then wipe the chemically strengthened microcrystalline glass sample clean, place it on the test path, and test its value. Photoelasticity mainly refers to the phenomenon that anisotropy and birefringence occur when a transparent material is subjected to force. 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 microcrystalline glass was tested using a digital display small load Vickers hardness tester VTD405 (Beijing Wowei Technology Co., Ltd.) in accordance with the national standard GB / T37900-2019 "Ultra-thin glass hardness and fracture toughness test method small load Vickers hardness indentation method". When the present invention performs the Vickers hardness test, the chemically strengthened microcrystalline glass sample with a length, width and thickness of 50mm×50mm×0.7mm is tested.

[0180] (7) Drop test

[0181] Average sandpaper drop height: refers to the ratio of the sum of the sandpaper drop heights of each sample of the same chemically strengthened glass-ceramic samples to the number of chemically strengthened glass-ceramic samples, which is used to characterize the drop resistance of chemically strengthened glass-ceramic. Take at least 10 identical chemically strengthened glass-ceramic samples for testing 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: Paste 120-grit sandpaper on the lower surface of the 160g model machine and place the model machine on the green figure LT-SKDL-CD drop machine.

[0184] Step 2. Place a 50mm×50mm×0.7mm chemically strengthened glass-ceramic sample to be tested directly under the model machine, with the chemically strengthened glass-ceramic sample facing the sandpaper. Make the model machine fall from a certain drop height to impact the chemically strengthened glass-ceramic sample directly under the model machine. If the chemically strengthened glass-ceramic sample does not break, the drop height of the model machine is increased according to a certain rule. For example, the drop height starts from 40cm, and the glass-ceramic sample is dropped once. If it does not break, increase the height by 10cm each time and drop it again until the chemically strengthened glass-ceramic sample breaks.

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

[0186] The surface scanning electron microscope image of the transparent microcrystalline glass 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 FIG. 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 and 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. Proportion 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 embodiments and comparative examples

[0196]

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

[0198]

[0199]

[0200] It can be seen from the above results that the transparent microcrystalline glass and chemically strengthened microcrystalline glass prepared in the embodiments of the present invention have excellent optical properties and mechanical properties.

[0201] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, 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, It is characterized in that Measured by molar percentage of oxides, the transparent microcrystalline glass comprises the following components: SiO 2 35.00%~60.00%、Al 2 O 3 8.00mol%~22.0mol%、Na 2 Of 10.00%~25.00%、Li 2 O1.00%~9.00%、P 2 O 5 0.50%~3.00%、ZrO 2 0.50%~3.50%、TiO 2 0.00%~0.50%、MgO0.00%~3.00%、B 2 O 3 0.00%~3.00%、K 2 O 0.00%~1.00%、CaO0.00%~2.00%、SnO 2 0.00%~0.30%; Among them, 0.80≤Al 2 O 3 / Na 2 O ≤ 1.20, P ≤ 2.00% 2 O 5 +ZrO 2 +TiO 2 ≤7.00%; The main crystal forms of the transparent microcrystalline glass 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 the number of grains with the longest dimension of 5 nm or more 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 the number of grains with the longest dimension of grains 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 of the grains being 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%.

2. The transparent glass-ceramic according to claim 1, It is characterized in that The mass of the crystalline phase in the transparent microcrystalline glass accounts for a proportion of the total mass of the transparent microcrystalline glass that is greater than or equal to 20% and less than or equal to 80%.

3. A method for preparing the transparent microcrystalline glass according to claim 1, It is 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 molded 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, It is 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, It is 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, It is characterized in that The heat treatment includes a nucleation treatment and a crystallization treatment.

7. The preparation method according to claim 6, It is 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, It is characterized in that The chemically strengthened microcrystalline glass is prepared by subjecting the transparent microcrystalline glass described in any one of claims 1 to 2 and / or the transparent microcrystalline glass 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, It is 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 a 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, It is 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, It is characterized in that The salt in the molten salt also 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 30000 ppm.

12. The preparation method according to claim 10, It is 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, It is 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, It is 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, It is characterized in that The chemically strengthened microcrystalline glass is used to prepare a protective cover plate for a display screen of a consumer electronic product.

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