Transparent glass ceramic, substrate glass, chemically strengthened glass ceramic and use thereof

Abstract

A transparent glass ceramic, a substrate glass, a chemically strengthened glass ceramic and a use thereof. The composition of the transparent glass ceramic meets: the content range of each specific oxide: 18.200≤Li2O / P2O5≤25.500; and 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. The transparent glass ceramic is suitable for batch production of glass ceramic products of large size and meeting the requirements of a cover plate, does not crack during heat treatment, and has excellent and uniform optical performance, excellent intensity performance, and a good display effect.

Description

Transparent glass-ceramics, substrate glass, chemically strengthened glass-ceramics and their applications

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application No. 202311800621.3, filed with the State Intellectual Property Office of China on December 25, 2023, entitled “Transparent microcrystalline glass, substrate glass, chemically strengthened microcrystalline glass and their applications”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of microcrystalline glass technology, and specifically relates to a transparent microcrystalline glass, substrate glass, chemically strengthened microcrystalline glass and their applications. Background Art

[0004] With the advancement of electronic display technology, glass has gradually replaced plastic materials in display devices as a protective cover material. Currently, there are two main types of cover glass used for electronic product protection on the market: chemically strengthened glass based on ordinary aluminosilicate glass, and chemically strengthened glass-ceramics, which are made by chemically strengthening glass-ceramics containing microcrystalline and glass phases. Glass-ceramics, due to its large content of nanocrystals, can inhibit the propagation of microcracks, resulting in significantly improved overall strength compared to ordinary aluminosilicate glass.

[0005] Glass-ceramics has gradually attracted industry attention due to its superior strength compared to ordinary glass. However, large-scale production of glass-ceramics for display screens, which require high optical quality and strength, is difficult. It is also difficult to ensure uniform composition and temperature distribution, leading to localized optical unevenness and cracking of the glass tiles.

[0006] It should be noted that this part of the content of this application only provides background technology related to this application, and does not necessarily constitute prior art or public knowledge. Summary of the Invention

[0007] In order to improve productivity, when microcrystalline glass is mass-produced, the production line usually first melts large-sized substrate glass bricks, then heat-treats the large-sized substrate glass bricks to prepare large-sized microcrystalline glass bricks, and then cold-processes the large-sized microcrystalline glass bricks to obtain multiple microcrystalline glass sheets of the required size specifications.

[0008] However, the existing microcrystalline glass solutions whose main crystal phases are petalite crystal phase and lithium disilicate crystal phase are prone to problems such as poor optical performance of microcrystalline glass bricks and easy cracking of microcrystalline glass bricks when they are put into mass production on the production line to produce large-sized microcrystalline glass bricks, such as microcrystalline glass bricks with length, width and thickness specifications of (200mm-500mm)×(100mm-500mm)×(10mm-40mm). Among them, the poor optical performance of microcrystalline glass bricks is mainly manifested in that the b-values ​​of different areas of the whole brick vary greatly, and some areas show undesirable colors, which causes the overall display effect of the microcrystalline glass to fail to meet the application requirements of the display cover, thereby reducing the product qualification rate. The cracking of microcrystalline glass bricks will directly reduce the output yield, which is not conducive to the mass production of microcrystalline glass products. Products that meet the optical performance requirements are prone to poor strength performance, especially poor drop resistance, which makes it difficult to meet the strength requirements of use.

[0009] The purpose of this application is to overcome the defects in the prior art of mass-producing microcrystalline glass (especially mass-producing large-sized microcrystalline glass bricks), such as uneven optical properties of the whole brick, cracking due to heat treatment, and inability to balance strength, and to provide a transparent microcrystalline glass, substrate glass, chemically strengthened microcrystalline glass and their applications.

[0010] The solution provided by the present application is suitable for the mass production of large-sized transparent microcrystalline glass bricks that meet the requirements of the cover plate and whose main crystal phases are petalite crystal phase and lithium disilicate crystal phase. During the preparation process of the large-sized transparent microcrystalline glass bricks, that is, when the large-sized substrate glass bricks are heat-treated to prepare transparent microcrystalline glass bricks, there is no cracking of the glass bricks, and the optical properties of the obtained transparent microcrystalline glass bricks are excellent and uniform. Afterwards, the obtained transparent microcrystalline glass bricks are subjected to cold processing (including cutting, CNC, polishing, etc. to obtain the required size specifications) and chemical strengthening treatment to obtain transparent chemically strengthened microcrystalline glass products that meet the requirements of optical performance, strength performance and display effect. The solution provided by the present application improves the production yield and economic benefits of transparent microcrystalline glass whose main crystal phases are petalite crystal phase and lithium disilicate crystal phase, and it is easy to realize the industrialized mass production of the transparent microcrystalline glass products.

[0011] In order to achieve the above objectives, this application provides the following technical solutions:

[0012] A transparent glass-ceramic, wherein the transparent glass-ceramic comprises a petalite crystalline phase and a lithium disilicate crystalline phase, wherein the petalite crystalline phase and the lithium disilicate crystalline phase have a higher weight percentage than other crystalline phases present in the transparent glass-ceramic;

[0013] Measured in mole percentage of oxides, the transparent glass-ceramics comprises:

[0014] SiO2: 60.90mol%-72.65mol%, Al2O3: 1.50mol%-5.00mol%, P2O5: 0.85mol%-1.50mol%, ZrO2: 2.00mol%-4.00mol%, Na2O: 0.00m ol%-1.00mol%, K2O: 0.00mol%-0.50mol%, Li2O: 20.00mol%-30.00mol%, CaO: 0.00mol%-1.60mol%, B2O3: 0.00mol%-1.00mol%;

[0015] The composition of the transparent glass-ceramics satisfies the following requirements, expressed as a molar percentage of each oxide in the transparent glass-ceramics:

[0016] 18.200≤Li2O / P2O5≤25.500;

[0017] 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. The oxide content and the specific oxide content relationship under the specific conditions satisfied by the technical solution of the present application can not only ensure the formation of the main crystalline phases of petalite and lithium disilicate, but also can avoid the problem of overall bluish, foggy or even cracking of the microcrystalline glass bricks when preparing microcrystalline glass bricks from large-sized substrate glass bricks while ensuring the good melting condition of the substrate glass bricks. This is conducive to the transparent microcrystalline glass to obtain excellent optical properties and strength, and thus the overall display effect of the transparent microcrystalline glass can meet the application requirements of the display cover. At the same time, the transparent microcrystalline glass of the present application can obtain high-strength chemically strengthened microcrystalline glass after chemical strengthening treatment.

[0018] In some embodiments, the composition of the transparent glass-ceramics satisfies the following requirements, expressed in terms of the molar percentage of each oxide in the transparent glass-ceramics:

[0019] 4.100≤(Li2O+Na2O+K2O+B2O3) / (P2O5+ZrO2+CaO)≤6.000; and / or,

[0020] 0.100≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900, preferably, 0.190≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900. By ensuring that the composition satisfies at least one of the above relationships, the network structure and crystalline structure of the transparent glass-ceramics can be further improved, thereby facilitating the formation of transparent glass-ceramics that meet specific structural requirements and have excellent properties (especially optical properties, strength properties, etc.).

[0021] It should be pointed out that in the above formulas of the present application, the content percentage is substituted into each formula on a molar basis, that is, the molar unit does not participate in the calculation of the formula. For example, if the molar content percentage of P2O5 is 0.85%, then 0.85% is substituted into the formula for calculation.

[0022] In some embodiments, the transparent glass-ceramics comprises, in terms of molar percentage of oxides:

[0023] SiO2: 67.50mol%-71.00mol%, Al2O3: 3.50mol%-5.00mol%, P2O5: 0.85mol%-1.50mol%, ZrO2: 2.50mol%-3.50mol%, Na2O: 0.00mol%-1.00mol%, K2O: greater than 0.00mol% and not greater than 0.50mol%, Li2O: 20.00mol%-25.00mol%, CaO: greater than 0.50mol% and not greater than 1.60mol%, B2O3: 0.00mol%-1.00mol%. By adjusting the content relationship of the necessary oxides, the network structure of the transparent glass-ceramics can be further improved, thereby ensuring the large-scale mass production of transparent glass-ceramics and ensuring the excellent optical properties and strength properties of the mass-produced products.

[0024] In some embodiments, the transparent glass-ceramics does not contain a quartz crystal phase. By avoiding the precipitation of a quartz crystal phase in a transparent glass-ceramics whose main crystal phases are petalite crystal phase and lithium disilicate crystal phase, the optical properties and overall uniformity of the transparent glass-ceramics can be further ensured.

[0025] In some embodiments, the transparent glass-ceramics has a crystallinity of 70.00 wt% or greater, preferably 80.00 wt% or greater. The average crystal size of the transparent glass-ceramics does not exceed 100 nm. A higher content of microcrystalline phases improves the mechanical strength of the glass-ceramics. A smaller average crystal size helps ensure the excellent optical properties of the transparent glass-ceramics.

[0026] In some embodiments, in the transparent glass-ceramics, the petalite crystalline phase accounts for 35.00wt%-50.00wt% of the transparent glass-ceramics, and the lithium disilicate crystalline phase accounts for 35.00wt%-50.00wt% of the transparent glass-ceramics. Adjusting the petalite crystalline phase and the lithium disilicate crystalline phase to meet an appropriate ratio facilitates the formation of a specific microstructure, thereby facilitating the transparent glass-ceramics to have high mechanical strength and fracture toughness.

[0027] In some embodiments, the transparent glass-ceramics further comprises one or more of a lithium silicate crystal phase, a lithium phosphate crystal phase, and a spodumene crystal phase as a secondary crystalline phase.

[0028] In some embodiments, the secondary crystalline phase in the transparent glass-ceramics accounts for less than 30.00 wt% of the transparent glass-ceramics, and preferably, the secondary crystalline phase accounts for less than 10.00 wt% of the transparent glass-ceramics. By controlling the content of the secondary crystalline phase to be low, it is more conducive to maintaining a high content of the primary crystalline phase, thereby ensuring the excellent mechanical strength properties of the transparent glass-ceramics.

[0029] In some embodiments, when the length, width, and thickness specifications of the transparent glass-ceramics are (200mm-500mm)×(100mm-500mm)×(10mm-40mm), the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics is ≤2.00, preferably ≤1.50, and more preferably ≤1.00. The smaller the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics that meets this specification, the better the overall uniformity and the better the optical effect of the transparent glass-ceramics of the present application when produced to this specification, which is conducive to ensuring that the cut glass-ceramics meet the requirements of excellent optical performance and display effect.

[0030] The nine locations are: (1) four test locations of the test circle I that is tangent to the long side and the adjacent short side of the main surface; (2) four test locations of the test circle II formed by the point on the line segment formed by the centers of the four test circles I that is closest to the middle of the long side or short side of the main surface; and (3) one location of the test circle III formed by the center point of the main surface.

[0031] In some embodiments, when the length, width, and thickness specifications of the transparent microcrystalline glass are (45mm-450mm)×(45mm-350mm)×(0.4mm-2.0mm), the range of the b-values ​​at nine locations on the main surface of the transparent microcrystalline glass is ≤0.30, preferably ≤0.10, and more preferably ≤0.06. The nine locations are: (1) four test locations of a test circle I tangent to the long side and the adjacent short side on the main surface; (2) four test locations of a test circle II formed by taking the point closest to the middle of the long side or short side of the main surface on the line segment formed by the centers of the four test circles I as the circle point; and (3) one location of a test circle III formed by taking the center point of the main surface as the circle center.

[0032] The smaller the range of the b values ​​at the nine locations on the main surface of the microcrystalline glass sheet of this specification, the better the overall uniformity of the transparent microcrystalline glass of the present application and the better the overall display effect.

[0033] In some embodiments, when the thickness of the transparent microcrystalline glass is 0.6 mm, the b value is ≤1.00, preferably the b value is ≤0.70, the haze is ≤0.25%, preferably the haze is ≤0.18%, and the transmittance of the transparent microcrystalline glass is ≥90.00% under light of 550 nm wavelength.

[0034] Preferably, when the transparent glass-ceramics has a thickness of 0.6 mm, a b-value ≤ 0.60, a haze ≤ 0.16%, and a transmittance ≥ 90.50% at a wavelength of 550 nm. The higher the transmittance, the smaller the b-value and the haze, the better the optical properties of the transparent glass-ceramics.

[0035] A substrate glass, which can be used to prepare the transparent glass-ceramics described in any one of the above embodiments through heat treatment, wherein the composition of the substrate glass, calculated in molar percentage of oxides, includes:

[0036] SiO2: 60.90mol%-72.65mol%, Al2O3: 1.50mol%-5.00mol%, P2O5: 0.85mol%-1.50mol%, ZrO2: 2.00mol%-4.00mol%, Na2O: 0.00m ol%-1.00mol%, K2O: 0.00mol%-0.50mol%, Li2O: 20.00mol%-30.00mol%, CaO: 0.00mol%-1.60mol%, B2O3: 0.00mol%-1.00mol%;

[0037] The composition of the substrate glass satisfies the following requirements, expressed as a molar percentage of each oxide in the substrate glass composition:

[0038] 18.200≤Li2O / P2O5≤25.500;

[0039] 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. By ensuring that the base glass meets the above composition requirements, not only can the base glass bricks be melted in a good condition, but also transparent micro-ceramic glass bricks with good overall uniformity, good display effect, excellent optical properties, and excellent mechanical properties can be produced, with the main crystal phases being petalite and lithium disilicate. This is conducive to improving the mass production yield of the transparent micro-ceramic glass of this system.

[0040] In some embodiments, the composition of the substrate glass satisfies the following conditions, expressed as a molar percentage of each oxide in the substrate glass composition:

[0041] 4.100≤(Li2O+Na2O+K2O+B2O3) / (P2O5+ZrO2+CaO)≤6.000; and / or,

[0042] 0.100≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900, preferably 0.190≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900. Ensuring that the composition satisfies at least one of the above relationships further improves the network structure of the glass, thereby facilitating the production of transparent glass-ceramics that meet specific structural requirements and exhibit excellent properties (particularly optical and strength properties).

[0043] In some embodiments, after synchronous thermal analysis testing, under a protective atmosphere of nitrogen, the substrate glass is heated from room temperature to 900°C at a heating rate of 10°C / min to obtain a heating DSC curve. In the heating DSC curve, there are at least two exothermic peaks, wherein the first exothermic peak temperature T1 is 600°C-730°C, and the second exothermic peak temperature T2 is 740°C-800°C, and T1 and T2 satisfy the relationship: 100°C ≥ T2-T1 ≥ 40°C, preferably 80°C ≥ T2-T1 ≥ 50°C. Large-sized substrate glass bricks made with substrate glass solutions that meet specific DSC curve characteristics are heat-treated under the production line process conditions for mass production of microcrystalline glass to produce transparent microcrystalline glass bricks whose optical properties and display effects meet the requirements for use in display screens. This can effectively solve the problems of glass brick cracking, large differences in b-values ​​between different areas of the glass bricks, localized undesirable colors, spots, poor display, and other problems that are prone to occur in the mass production of microcrystalline glass bricks in the prior art.

[0044] In some embodiments, after synchronous thermal analysis testing, the substrate glass is heated from room temperature to 1400°C at a heating rate of 10°C / min and kept warm for 10 minutes under a protective atmosphere of nitrogen, and then cooled from 1400°C to 450°C at a cooling rate of 10°C / min, to obtain a cooling DSC curve. In the cooling DSC curve, within the range of 500°C-900°C, the sum of the integrated areas of the exothermic peaks and endothermic peaks contained therein is S≤10, preferably there is no endothermic peak and / or no exothermic peak, and more preferably S=0. Large-sized substrate glass bricks made of substrate glass solutions that meet specific DSC curve characteristics are heat-treated under the production line process conditions of large-scale microcrystalline glass production to produce transparent microcrystalline glass bricks whose optical properties and display effects meet the requirements for display screens. This can effectively solve the problems of glass brick cracking, large differences in b-values ​​between different areas of the glass bricks, localized undesirable colors, spots, poor display, and other problems that are prone to occur in the mass production of microcrystalline glass bricks in the prior art.

[0045] In some embodiments, the substrate glass is heated from room temperature to T at a heating rate of 10°C / min. 1-30 Temperature, and keep it at this temperature for 240 minutes for treatment, and the content of quartz crystal phase in the product obtained after treatment is less than 15wt%; wherein, T 1-30 =T1-30℃.

[0046] In some embodiments, the substrate glass is heated from room temperature to T at a heating rate of 10°C / min. 1-60 Temperature, and keep it at this temperature for 240 minutes for treatment, the content of quartz crystal phase in the product obtained after treatment is less than 5wt%, preferably no quartz crystal phase; wherein, T 1-60 =T1-60℃.

[0047] In T 1-30 and / or T 1-60 The substrate glass that meets the specific quartz crystal phase content requirements after heat treatment at a certain temperature can effectively avoid the precipitation of quartz crystal phase in the target microcrystalline glass bricks that affects the optical properties of the microcrystalline glass when the target microcrystalline glass is prepared by heat treatment, thereby ensuring the large-scale production of large-size transparent microcrystalline glass bricks that meet the use requirements.

[0048] A chemically strengthened glass-ceramic, wherein the composition at the center of the chemically strengthened glass-ceramic is the same as the composition of the transparent glass-ceramic described in any of the above embodiments, the chemically strengthened glass-ceramic includes a compressive stress layer region extending from the surface of the transparent glass-ceramic to a compression depth, and has tensile stress within the chemically strengthened glass-ceramic. The formation of the compressive stress layer on the surface of the transparent glass-ceramic further improves the mechanical properties of the transparent glass-ceramic.

[0049] In some embodiments, the chemically strengthened microcrystalline glass is obtained by chemically strengthening the transparent microcrystalline glass described in any one of the above embodiments, wherein the salt bath used for chemical strengthening treatment is a mixed molten salt, and the composition of the mixed molten salt includes: 0<NaNO3<100wt%, 0<KNO3<100wt%, 0<LiNO3≤0.2wt%.

[0050] Preferably, the temperature of the salt bath for chemical strengthening treatment is 430° C.-530° C., and the chemical strengthening treatment time is 0.5 h-15.0 h. Using the above strengthening process for chemical strengthening is beneficial to improving the chemical strengthening efficiency while ensuring that the chemically strengthened glass-ceramics obtains the desired stress level.

[0051] In some embodiments, the surface Na2O concentration of the chemically strengthened glass-ceramics is 5.0 wt% to 20.0 wt%. By meeting the surface Na2O concentration within the above range, the chemically strengthened glass-ceramics can not only have a better surface stress level, but also have better weather resistance and chemical durability.

[0052] In some embodiments, the chemically strengthened glass-ceramics have a CS_50 of 110-200 MPa, where CS_50 refers to the compressive stress at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramics. The CS_50 of the chemically strengthened glass-ceramics within the above range indicates that the compressive stress at a depth of 50 μm from the surface of the chemically strengthened glass-ceramics is high, indicating that the chemically strengthened glass-ceramics has a higher surface stress level. A higher surface compressive stress level can offset more residual energy from a drop collision, thereby ensuring excellent damage resistance.

[0053] In some embodiments, the chemically strengthened glass-ceramics have a |CT_AV| of 84-140 MPa, where |CT_AV| refers to the absolute value of the average tensile stress. A |CT_AV| value within this range indicates that the chemically strengthened glass-ceramics have a high tensile stress level, reflecting a high surface stress level. A higher surface compressive stress level can offset more residual energy from a drop collision, thereby ensuring excellent damage resistance.

[0054] In some embodiments, the chemically strengthened glass-ceramics has a compressive stress layer depth DOL_0 of 0.18t-0.25t, where t is the thickness of the chemically strengthened glass-ceramics. The chemically strengthened glass-ceramics having a DOL_0 within the above range indicates that the chemically strengthened glass-ceramics has a high compressive stress layer depth, which is more conducive to offsetting the energy that drives crack propagation, thereby ensuring excellent damage resistance.

[0055] In some embodiments, the chemically strengthened glass-ceramics having a thickness of 0.6 mm is subjected to multiple fixed-point height drop tests using 120-grit sandpaper. The fixed-point height of the test is 1.0 m. The chemically strengthened glass-ceramics are dropped to break ≥30 times, preferably ≥50 times. When the chemically strengthened glass-ceramics are broken after being dropped from the fixed-point height, a greater number of drops to break indicates better drop damage resistance of the chemically strengthened glass-ceramics.

[0056] A method for preparing a transparent microcrystalline glass as described in any one of the above embodiments, comprising: heat-treating the substrate glass as described in any one of the above embodiments to obtain the transparent microcrystalline glass.

[0057] The heat treatment described in this application includes nucleation treatment and crystallization treatment, wherein the temperature of the nucleation treatment is (Tg-20°C) to (Tg+40°C), the time of the nucleation treatment is 0min-6000min, the temperature of the crystallization treatment is (T1-20°C) to (T1+20°C), and the time of the crystallization treatment is 30min-6000min; Tg is the glass transition temperature of the substrate glass.

[0058] Preferably, the heating rate of the heat treatment process is 5-15°C / min.

[0059] A glass device, wherein the glass device comprises the transparent micro-ceramic glass as described in any one of the above embodiments or comprises the chemically strengthened micro-ceramic glass as described in any one of the above embodiments.

[0060] An electronic device, wherein the electronic device includes the transparent micro-ceramic glass as described in any one of the above embodiments or includes the chemically strengthened micro-ceramic glass as described in any one of the above embodiments.

[0061] The embodiments of the present application have the following advantages or beneficial effects:

[0062] This application optimizes the glass formula and adopts a glass solution that meets specific composition requirements, especially the oxide content and specific oxide content relationship under specific conditions. It can solve the problem of easy cracking of microcrystalline glass bricks when mass-producing large-sized transparent microcrystalline glass with the main crystal phases being petalite crystal phase and lithium disilicate crystal phase. At the same time, it can ensure that the prepared transparent microcrystalline glass has both excellent optical properties and strength properties, ensuring that its display effect can meet the requirements.

[0063] Among them, the oxide content and the specific oxide content relationship under the specific conditions met by the technical solution of the present application can not only ensure the formation of the main crystalline phases of petalite and lithium disilicate, but also can avoid the problem of overall blueing, fogging, or even cracking of the microcrystalline glass bricks when preparing microcrystalline glass bricks from large-sized substrate glass bricks while ensuring the good melting condition of the substrate glass bricks, which is conducive to the transparent microcrystalline glass obtaining excellent optical properties and strength, thereby enabling the overall display effect of the transparent microcrystalline glass to meet the application requirements of the display cover. At the same time, after chemical strengthening treatment, the transparent microcrystalline glass of the present application can obtain high-strength chemically strengthened microcrystalline glass, which has been verified to have excellent drop resistance.

[0064] Verification shows that, at large sizes, the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics prepared using the technical solution of the present application is ≤2.00; at small sizes, the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics prepared using the technical solution of the present application is ≤0.30, preferably ≤0.10. This indicates that, regardless of whether the size is large or small, the b-value differences between different areas of the main surface of the transparent glass-ceramics of the present application are small, the transparent glass-ceramics have good optical properties, and the overall display effect can meet the application requirements of display cover plates. At large sizes, the glass-ceramics can achieve uniform b-values, which helps ensure a high product yield.

[0065] The present application adopts a large-scale base material glass brick made of a specific base material glass solution that meets the specific DSC curve characteristics. Under the production line process conditions of mass production of microcrystalline glass, heat treatment is carried out to produce transparent microcrystalline glass bricks whose optical properties and display effects meet the requirements of display screens. It can well solve the problems of glass brick cracking, large differences in b-values ​​in different areas of glass bricks, localized unexpected colors, spots, poor display, etc. during mass production of microcrystalline glass bricks in the prior art. Therefore, before preparing large-scale microcrystalline glass bricks, glass samples can be melted according to the glass formula. The DSC curve characteristics obtained can be used to pre-verify whether the glass solution is suitable for the production of large-scale microcrystalline glass, especially qualified microcrystalline glass products with large thickness. If it does not meet the requirements, it can be adjusted in time until it meets the specific DSC curve characteristics before the preparation of large-scale products. This can greatly save time and cost and effectively avoid waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0067] FIG1 is a DSC graph of the substrate glass of Example 1 at a lower temperature;

[0068] FIG2 is a DSC curve of the substrate glass of Comparative Example 4 at a lower temperature;

[0069] FIG3 is a DSC graph of the substrate glass of Example 1 at elevated temperatures;

[0070] FIG4 is a DSC graph of the substrate glass of Example 22 at elevated temperatures;

[0071] FIG5 is a DSC graph of the substrate glass of Comparative Example 1 at elevated temperatures;

[0072] FIG6 is a DSC graph of the substrate glass of Comparative Example 2 at elevated temperatures;

[0073] FIG7 is a graph showing the substrate glass of Example 3 after heat treatment process A (crystallization temperature is T 1-60 , crystallization treatment time is 240min), the XRD diffraction pattern of the obtained product;

[0074] FIG8 is a graph showing the substrate glass of Comparative Example 2 after heat treatment process A (crystallization temperature is T 1-60 , crystallization treatment time is 240min), the XRD diffraction pattern of the obtained product;

[0075] FIG9 is an XRD diffraction pattern of the glass-ceramics obtained after the substrate glass of Example 3 is treated by heat treatment process B;

[0076] FIG10 is an XRD diffraction pattern of the glass-ceramics obtained after the substrate glass of Comparative Example 2 is treated by heat treatment process B;

[0077] FIG11 is a schematic diagram of the structure of Li3PO4 crystals attached to lithium silicate crystals;

[0078] Figure 12 is a standard XRD diffraction pattern of quartz appearing in glass-ceramics;

[0079] FIG13 is a schematic diagram of nine test positions when performing b-value tests on the main surface of a glass-ceramic. The circles in the figure are all test circle positions;

[0080] FIG14 is a schematic diagram of a glass-ceramic flower piece;

[0081] FIG15 is a comparison of XRD diffraction curves at the maximum b-value position and the minimum b-value position of the 0.6 mm thick glass-ceramic sheet of Example 1 in the nine b-value tests;

[0082] FIG16 is a comparison of XRD diffraction curves at the maximum b-value position and the minimum b-value position of the 0.6 mm thick glass-ceramic sheet (with flower pieces) of Comparative Example 6 in the nine b-value tests;

[0083] FIG17 is a transmittance curve of the glass-ceramics obtained after the substrate glass of Example 6 is subjected to heat treatment process B, with a thickness of 0.6 mm;

[0084] FIG18 is a transmittance curve of the glass-ceramics obtained from the substrate glass of Comparative Example 4 after heat treatment process B, with a thickness of 0.6 mm;

[0085] FIG19 is a picture of the substrate glass brick of Comparative Example 9;

[0086] FIG20 is a picture of the cracking of the microcrystalline glass brick obtained after the base glass brick in Comparative Example 7 was treated by heat treatment process B. DETAILED DESCRIPTION

[0087] The endpoints and any values ​​of the scope disclosed in this article are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article. Wherein, the terms "optional" and "optional" all refer to and may include, but may not include (or may have, or may not have). As used herein, "and / or" is inclusive, for example, "A and / or B" refers to only A, or only B, or both A and B.

[0088] Glossary and test methods:

[0089] Base glass: also known as basic glass, refers to glass that has not been nucleated, crystallized or strengthened.

[0090] Glass-ceramics: also known as glass ceramics or crystallized glass, is a type of solid composite material that contains both a glass phase and a crystal phase (also known as a microcrystalline phase or a crystal phase).

[0091] Transparent glass-ceramics: refers to glass-ceramics that is transparent in the visible light range.

[0092] Chemically strengthened glass-ceramics: refers to the solid composite material obtained by chemically strengthening glass-ceramics.

[0093] In the present application, when high-temperature chemical strengthening treatment is carried out, the alkali metal ions with large ionic radius (such as potassium ions and sodium ions) in the molten salt bath will replace the alkali metal ions with small ionic radius (such as sodium ions and lithium ions) in the microcrystalline glass, thereby generating an exchange ion volume difference and generating compressive stress on the surface of the microcrystalline glass.

[0094] Main crystalline phase: refers to a crystalline phase having a higher weight content than other crystalline phases present in the transparent microcrystalline glass.

[0095] Main surface: refers to the surface with the largest surface area in a glass brick or glass sheet, such as the upper or lower surface of a horizontally placed cover glass.

[0096] Transmittance: The ratio of the radiant energy that is projected and passes through the object to the total radiant energy that is 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.

[0097] b value: belongs to the Lab color model, a color model developed by the International Illumination Commission. Positive and negative b values ​​represent yellow and blue.

[0098] Haze: Haze is the percentage of transmitted light intensity that deviates from the incident light by more than 2.5° to the total transmitted light intensity.

[0099] Nucleation: Through heat treatment, the nucleating material in the glass grows small crystal nuclei.

[0100] Crystallization: Through heat treatment, the glass grows a certain crystal based on the crystal nucleus.

[0101] Speckling: This occurs when strong light strikes the glass from the side, causing localized color changes on the main surface of the glass and / or uneven coloring across the entire glass, as shown in Figure 14. Products exhibiting speckling fail to meet the display requirements of display cover glass and are therefore considered defective during production.

[0102] Precursor: A form of existence before obtaining the target object.

[0103] Glass transition temperature: Tg, unit ℃, also known as the brittle temperature of glass, which is the highest temperature at which glass becomes brittle, and the corresponding viscosity is 10 12 Pa·s, also known as the upper annealing temperature, is the temperature at which internal stresses in glass products caused by uneven cooling are eliminated. In this application, Tg is determined by the DSC curve of the substrate glass at elevated temperatures. This is manifested on the DSC curve as a step where the baseline shifts toward the endothermic direction. Tangent lines are drawn between the two baseline extensions before and after the step and the inflection point of the curve. The average of the temperatures corresponding to the two intersection points is the glass transition temperature.

[0104] CS_50: refers to the compressive stress value at a depth of 50μm measured from the main surface of the chemically strengthened microcrystalline glass.

[0105] 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 glass to the position close to the surface where the compressive stress is zero in the thickness direction of the glass.

[0106] |CT_AV|: The absolute value of the average tensile stress in the tensile stress layer, specifically the absolute value of the average value of all tensile stresses in the tensile stress layer.

[0107] Test conditions for CS_50, |CT_AV|, and DOL_0: Tested using an Orihara SLP-2000 (Japan), with a light source wavelength of 518 nm, SOC = 25.5 (nm / cm) / MPa, refractive index = 1.54, and exposure time: 300 usec.

[0108] When testing surfaces CS_50, |CT_AV|, and DOL_0, first apply conductive fluid to the stress gauge. Then, clean the chemically strengthened glass-ceramic sample and place it on the test path to measure its stress. The stress gauge is an SLP-2000, and the conductive fluid used has a refractive index of 1.51.

[0109] Optical performance test of glass-ceramics with a thickness of more than 2 mm: The YJD-3600C haze meter was used to test the b-values ​​of different parts of the main surface of the glass-ceramics, and the b-value range data and b-value average data of nine locations were obtained. In this application, the test aperture of the YJD-3600C haze meter used is 16.5 mm. The instrument complies with the dual standards of ASTM D1003 / D1044 and ISO13468 / ISO14782. To ensure accuracy, this test method is suitable for testing glass-ceramics with a thickness of more than 2 mm. In this application, the transmission mode of the YJD-3600C haze meter was selected to test the optical properties of the glass-ceramics.

[0110] Optical performance test of glass-ceramics with a thickness of less than 2 mm: This application uses the Konica Minolta spectrophotometer CM-3600A from Japan to test the haze, L value, a value, and b value of the glass-ceramics. The test aperture of the spectrophotometer CM-3600A used is 25.6 mm. This application uses the Shimadzu UV-2000 ultraviolet-visible spectrophotometer to test the transmittance and its curve. To ensure accuracy, this test method is suitable for testing glass sheets with a thickness of less than 2 mm. In this application, the transmission mode of the spectrophotometer CM-3600A is selected to test the optical properties of the glass-ceramics.

[0111] Synchronous thermal analysis test: Using a Mettler-Toledo TGA / DSC3+ synchronous thermal analyzer, the test is carried out according to the required process. The obtained curve is called a DSC curve, including a heating DSC curve and a cooling DSC curve.

[0112] Temperature DSC curve test conditions: After grinding the substrate glass and sieving it through a 200-mesh sieve, obtain the sample to be tested. Weigh approximately 20 mg of the sample and heat it from room temperature to 900°C at a heating rate of 10°C / min under a nitrogen atmosphere to obtain the sample's temperature DSC curve. The differential thermal analysis instrument used in this application to test the temperature DSC curve is a Mettler-Toledo TGA / DSC3+ simultaneous thermal analyzer. The standard used in the test is α-Al2O3 powder. The sample container is a platinum crucible. The instrument is placed in an ambient temperature of 24°C and the air humidity is 40%.

[0113] The test conditions of the cooling DSC curve are as follows: after grinding the substrate glass, sieve it through 200 mesh to obtain the sample to be tested, weigh about 20 mg of the sample, heat it from room temperature to 1400°C at a heating rate of 10°C / min under a nitrogen atmosphere, keep it warm for 10 minutes, and then cool it to 450°C at 10°C / min to obtain the cooling DSC curve of the sample. The cooling DSC curve is processed by origin 2022b software, and the sum of the integral areas of the endothermic peak and the exothermic peak on the curve can be obtained by Gaussian fitting. The differential thermal analysis instrument used in this application to test the cooling DSC curve is a Mettler-Toledo TGA / DSC3+ synchronous thermal analyzer. The standard used in the test is α-Al2O3 powder, the container for placing the sample is a platinum crucible, the ambient temperature of the instrument is 24°C, and the air humidity is 40%.

[0114] Glass thickness: measured by laser thickness gauge.

[0115] Glass sheet size measurement: Use a 2D measuring machine (Miyu MY-YXCL-4030) to test. Place the glass sheet to be tested on the measuring table of the 2D measuring machine, set the program, and the instrument will automatically grab and measure the length and width of the glass sheet.

[0116] XRD testing: The glass-ceramics were crushed and ground into samples with a particle size of less than 75 μm. The ground samples were tested using an X-ray diffractometer to obtain XRD diffraction peak curves and XRD diffraction data. The X-ray diffractometer was a Shimadzu XRD-6100, with a 2θ value of 10-80°, a scan speed of 3° / min, an operating voltage of 40 kV, and an operating current of 30 mA.

[0117] Determination of crystal phase: The XRD test results (RAW format) were imported into the X-ray diffraction data Rietveld refinement software JADE Standard 8.6 for fitting and analysis to determine the crystal phase in the micro-ceramic glass sample.

[0118] The crystal content in this application refers to the percentage of crystals or crystalline phases in the mass of the microcrystalline glass, which is a weight percentage.

[0119] Determination of Crystalline Content: Import XRD test results (RAW format) into the X-ray diffraction data Rietveld refinement software JADE Standard 8.6 for fitting and calculation to determine the crystal content of the glass-ceramic sample. Specifically, the ratio of the fitted crystalline phase peak area to the total fitted peak area is the crystal content.

[0120] Average crystal size test: The average crystal size of the sample can be calculated using the result data obtained from the XRD test according to the Scherrer formula D = Kλ / (βcosθ). Wherein, λ is the X-ray wavelength, λ = 0.154056nm, β is the half-height width of the diffraction peak, K = 0.89, and θ is the Bragg diffraction angle. Specifically, the RAW file (diffraction pattern) output by the XRD instrument is curve fitted in JADE Standard 8.6 software. Jade outputs a fitting report. According to the angle 2θ value and Peak FWHM value corresponding to each diffraction peak in the fitting report, the Peak FWHM value is converted to radians: β = (FWHM / 180×3.14). The grain size of each diffraction peak is calculated by the Scherrer formula D = Kλ / (βcosθ) and then averaged to obtain the average crystal size.

[0121] Surface Na2O concentration test: The surface Na2O concentration is equal to the surface Na2O mass / total surface oxide mass, where the total surface oxide mass includes oxides such as SiO2, Al2O3, P2O5, ZrO2, Na2O, K2O, CaO that can be accurately tested by XRF, and does not include the content of oxides such as Li2O and B2O3 that cannot be accurately tested by XRF. The surface Na2O concentration of the chemically strengthened microcrystalline glass in this application is measured by X-ray fluorescence spectrometer (XRF). The surface Na element content in the chemically strengthened microcrystalline glass is measured by XRF, and then the surface Na2O concentration is calculated. The calculation method is: surface Na2O concentration = (surface Na element content × relative molecular mass of Na2O) / (relative atomic mass of Na element × 2). It should be understood that the surface Na element content = Na element mass / total element mass, and the total element mass = total oxide mass. The equipment used for the test is Thermo Scientific ARL TM PERFORM'X. The target material was Rh (rhodium), the light tube voltage was 40 kV, the current was 60 mA, the collimator was 0.15, the crystal was LiF200, the detector was FPC, the test range was a 29 mm circle, and the analysis software was UniQuant standardless analysis. XRF testing used standardless testing, and the concentration of elements with atomic numbers 6 and below or their oxides in the glass was not measured. That is, in this application, when measuring the surface Na2O concentration by XRF, the total mass of the surface oxide does not include the mass of elements with atomic numbers 6 and below or their oxides in the glass.

[0122] Fixed height drop test:

[0123] (1) Apply 120-grit sandpaper to the bottom surface of a 187g model machine and place the model machine on a Wonder Inno drop tester.

[0124] (2) Place a glass-ceramic sample to be tested with a length, width and thickness of 50 mm × 50 mm × 0.6 mm on a smooth marble plate directly below the model machine, with the glass-ceramic sample facing the sandpaper;

[0125] (3) Drop the model machine from a fixed height of 1.0 m to impact the glass-ceramic sample located directly below the model machine. If the glass-ceramic sample does not break, replace the sandpaper on the lower surface of the model machine and repeat the above drop impact process until the glass-ceramic breaks. Record the number of drops until the glass-ceramic breaks.

[0126] At least 10 identical glass-ceramic samples from each batch are subjected to a fixed-height drop test. The average value of the test results of the 10 glass-ceramic samples is calculated to characterize the drop resistance of the glass-ceramic.

[0127] As described above, in some embodiments of the present application, a transparent microcrystalline glass and a substrate glass for preparing the transparent microcrystalline glass are provided. The substrate glass can be prepared into the transparent microcrystalline glass by heat treatment. Therefore, it can be understood that, in terms of oxide content, the composition of the substrate glass is the same as that of the transparent microcrystalline glass.

[0128] In some embodiments of the present application, the transparent glass-ceramics contains a main crystalline phase of petalite (LiAlSi4O 10 ) crystalline phase and the main crystalline phase lithium disilicate (Li2Si2O5) crystalline phase. The "main crystalline phase" here means that the crystalline phase content accounts for the majority in the transparent microcrystalline glass of the present application, that is, the petalite crystalline phase and the lithium disilicate crystalline phase have a higher weight percentage than other crystalline phases present in the transparent microcrystalline glass.

[0129] In some embodiments of the present application, the composition of the transparent glass-ceramics or substrate glass includes, by mole percentage of oxides: SiO2: 60.90mol%-72.65mol%, Al2O3: 1.50mol%-5.00mol%, P2O5: 0.85mol%-1.50mol%, ZrO2: 2.00mol%-4.00mol%, Na2O: 0.00mol%-1.00mol%, K2O: 0.00mol%-0.50mol%, Li2O: 20.00mol%-30.00mol%, CaO: 0.00mol%-1.60mol%, B2O3: 0.00mol%-1.00mol%;

[0130] The composition of the transparent glass-ceramics or substrate glass satisfies the following requirements, expressed as a molar percentage of each oxide in the transparent glass-ceramics or substrate glass:

[0131] 18.200≤Li2O / P2O5≤25.500;

[0132] 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. By satisfying the oxide content under specific conditions and the relationship between the specific oxide contents, it is possible to not only ensure the formation of the main crystalline phases of petalite and lithium disilicate, but also to avoid the problem of overall blueing, fogging, or even cracking of the microcrystalline glass bricks when preparing microcrystalline glass bricks from large-sized substrate glass bricks while ensuring the good melting condition of the substrate glass bricks. This is beneficial for transparent microcrystalline glass to obtain excellent optical properties and strength, and thus the overall display effect of the transparent microcrystalline glass can meet the application requirements of the display cover. At the same time, the transparent microcrystalline glass of the present application can obtain high-strength chemically strengthened microcrystalline glass after chemical strengthening treatment.

[0133] In the present application, SiO2 is an oxide that forms the network skeleton of the glass, and is used to stabilize the network structure of the substrate glass and microcrystalline glass. It is an important component of crystalline phases such as lithium silicate, petalite, β-spodumene and quartz. When the SiO2 content is too low, the glass tends to have a higher thermal expansion coefficient and reduced thermal shock resistance; when the SiO2 content is too high, the solubility of the glass will deteriorate, or the viscosity of the molten glass will increase, making it difficult to clarify the glass, making the glass molding more difficult, reducing productivity, and also causing the crystallization heat treatment time of the substrate glass to become longer. In the present application, the transparent microcrystalline glass or substrate glass contains 60.90mol%-72.65mol% of SiO2.

[0134] In some embodiments, the transparent microcrystalline glass or substrate glass may contain 60.90mol%-72.65mol%, 60.90mol%-72.00mol%, 60.90mol%-71.00mol%, 60.90mol%-70.00mol%, 60.90mol%-69.00mol%, 60.90mol%-68.00mol%, 62.00mol%-72.00mol%, 63.00mol%-72.00mol%, 64.00mol%-72.00mol%, 65.00mol%-72.00mol%, 66.00mol%-72.00mol%, 67.00mol%-72.00mol% or 67.50mol%-71.00mol% of SiO2. In some embodiments, the transparent glass-ceramics or substrate glass may contain 60.90 mol%, 62.00 mol%, 63.00 mol%, 64.00 mol%, 65.00 mol%, 66.00 mol%, 67.00 mol%, 67.50 mol%, 68.00 mol%, 69.00 mol%, 70.00 mol%, 71.00 mol%, 72.00 mol% or 72.65 mol% of SiO2, or may contain SiO2 within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the performance required by the present application can be obtained.

[0135] In the present application, Al2O3 can be used to construct the glass skeleton and is an indispensable component for the formation of petalite. Al2O3 is coordinated around the crystal nucleus to form a "center-shell" structure. This structure makes it difficult for the crystal nucleus components to be supplied from the outer part of the shell, and the crystal nucleus is not easy to grow, and it is easy to form multiple tiny grains. When the Al2O3 content is too little, the glass has a tendency to have a higher thermal expansion coefficient, its chemical durability is reduced, and the crystal nucleus is easy to become larger, and the microcrystalline glass is prone to white turbidity; when the Al2O3 content is too much, the glass's solubility deteriorates, production becomes difficult, and mullite crystals are easily precipitated, causing the glass to lose transparency. In the present application, the transparent microcrystalline glass or substrate glass contains 1.50mol%-5.00mol% Al2O3. Al2O3 that meets this content range is conducive to stabilizing the glass network structure, improving the mechanical properties and chemical durability of the transparent microcrystalline glass, and inhibiting the phase separation of the glass, reducing the thermal expansion coefficient, and increasing the strain point.

[0136] In some embodiments, the transparent glass-ceramics or substrate glass may contain 1.50 mol%-5.00 mol%, 3.50 mol%-5.00 mol%, 3.50 mol%-4.00 mol%, 3.50 mol%-4.50 mol%, 4.00 mol%-5.00 mol% or 4.50 mol%-5.00 mol% of Al2O3. In some embodiments, the transparent glass-ceramics or substrate glass may contain 1.50 mol%, 2.00 mol%, 2.50 mol%, 3.00 mol%, 3.50 mol%, 4.00 mol%, 4.50 mol% or 5.00 mol% of Al2O3, or may contain Al2O3 within a numerical range consisting of any two of the above specific numerical values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the required performance of the present application can be obtained.

[0137] In the present application, Li2O is the main component of the petalite crystal phase and the lithium silicate crystal phase, and is also an essential component for chemical strengthening. When the Li2O content is too little, it is easy to cause the glass meltability to decrease or the viscosity to increase, making the glass liquid difficult to clarify, the base glass molding difficult, and causing the precipitation of impurities such as mullite in the glass, causing the glass to lose transparency; and when the Li2O content is too much, the crystallization ability of the glass becomes too strong, the glass has a tendency to lose transparency, and the microcrystalline glass becomes easily broken. In the present application, the transparent microcrystalline glass or base glass contains 20.00mol%-30.00mol% of Li2O. Li2O that meets this content range is conducive to ensuring that the transparency, melting and crystallization ability of the microcrystalline glass meet the requirements.

[0138] In some embodiments, the transparent glass-ceramics or substrate glass may contain 20.00 mol%-30.00 mol%, 20.00 mol%-25.00 mol%, 20.00 mol%-24.00 mol%, 20.00 mol%-23.00 mol%, 20.00 mol%-22.00 mol%, 20.00 mol%-21.00 mol%, or 21.00 mol%-23.00 mol% of Li2O. In some embodiments, the transparent glass-ceramics or substrate glass may contain 20.00 mol%, 21.00 mol%, 22.00 mol%, 23.00 mol%, 24.00 mol%, 25.00 mol%, 26.00 mol%, 27.00 mol%, 28.00 mol%, or 30.00 mol% of Li2O, or may contain Li2O within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired properties of the present application can be obtained.

[0139] In the present application, P2O5 is a glass-forming oxide that exists in the network structure as phosphorus-oxygen tetrahedrons [PO4]. P2O5 appears first during the heat treatment process, first causing the glass to phase separate and segregate to form the amorphous precursor phase Li3PO4. Then, with Li3PO4 acting as a non-uniform nucleation point, crystalline phases such as lithium silicate grow attached to the amorphous Li3PO4. As the P2O5 content increases, the number of non-uniform nucleation points increases, and the grains with Li3PO4 as nucleation points are effectively refined, which is beneficial to improving the overall transmittance of the microcrystalline glass, the uniformity of the glass, and reducing the b value. However, when the P2O5 content is too high, the upper limit of crystallization temperature increases, and more Li3PO4 crystals are easily generated, resulting in insufficient Li2O content to form lithium silicate and petalite, which in turn causes the substrate glass to easily precipitate quartz crystals, resulting in a decrease in the transmittance of the microcrystalline glass and a decrease in the overall optical uniformity of the microcrystalline glass. What's worse, it causes the substrate glass to directly crystallize during melt molding. However, when the P2O5 content is too low, coarse ZrO2 crystals tend to precipitate, causing the glass to lose clarity. In this application, the transparent glass-ceramics or base glass contains 0.85 mol% to 1.50 mol% P2O5. This P2O5 content range helps ensure high transmittance and good optical uniformity in the glass-ceramics, significantly reduces the b-value, and achieves optimal gain.

[0140] In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.85 mol%-1.50 mol%, 0.85 mol%-1.40 mol%, 0.85 mol%-1.30 mol%, 0.85 mol%-1.20 mol%, 0.85 mol%-1.10 mol%, 0.85 mol%-1.00 mol%, or 1.00 mol%-1.30 mol% of P2O5. In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.85 mol%, 0.95 mol%, 1.00 mol%, 1.10 mol%, 1.20 mol%, 1.30 mol%, 1.40 mol%, or 1.50 mol% of P2O5, or may contain P2O5 within a numerical range consisting of any two of the above specific numerical values ​​as endpoints. It should be understood that, in a specific embodiment, any of the above ranges can be combined with any other ranges, as long as the transparent microcrystalline glass or substrate glass with the required performance of the present application can be obtained.

[0141] In the present application, since P2O5 preferentially generates amorphous Li3PO4 during heat treatment, the increase in P2O5 will inevitably compete for more Li2O, thereby reducing the production of lithium silicate and petalite. Therefore, a certain degree of Li2O needs to be supplemented. In this regard, in the present application, the composition of the transparent microcrystalline glass or substrate glass, expressed as the molar percentage of each oxide in the composition, satisfies the following conditions: 18.200≤Li2O / P2O5≤25.500, where the chemical formula represents the molar percentage of the oxide, which is beneficial to ensure the formation of the main crystalline phase and improve the strength performance of the glass. In some embodiments, the value of Li2O / P2O5 can be, for example, 18.200, 18.300, 18.400, 18.500, 18.600, 18.700, 18.800, 18.900, 19.000, 19.100, 19.200, 19.300, 19.400, 19.500, 19.600, 19.700, 19.800, 19.900, 20.000, 20.100, 20.200, 20.300, 20.400, 20.500, 20.600, 20.700, 20.800, 20.900, 21.000, 21.100, 21.200, 21.300, 21.400, 21.500, 21.600, 21.700, 21.800, 21.9 00, 22.000, 22.100, 22.200, 22.300, 22.400, 22.500, 22.600, 22.700, 22.800, 22.900, 23.000, 23.100, 23.200, 23.300, 23.400, 23.500, 23.600, 23.700, 23.800, 23.900, 2 The value of the transparent glass-ceramics or substrate glass can be 4.000, 24.100, 24.200, 24.300, 24.400, 24.500, 24.600, 24.700, 24.800, 24.900, 25.000, 25.100, 25.200, 25.300, 25.400 or 25.500, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired performance of the present application can be obtained.

[0142] In the present application, an appropriate amount of ZrO2 exists in the residual glass phase after heat treatment, which is beneficial to improving the mechanical properties of the microcrystalline glass. However, excessive ZrO2 increases the difficulty of melting the substrate glass and easily leads to the formation of white zirconium precipitates in the substrate glass, which is not conducive to the production of transparent microcrystalline glass. In the present application, the transparent microcrystalline glass or substrate glass contains 2.00mol%-4.00mol% ZrO2. ZrO2 that meets this content range is conducive to the production of transparent microcrystalline glass and improves the mechanical properties of transparent microcrystalline glass.

[0143] In some embodiments, the transparent microcrystalline glass or substrate glass may contain 2.00mol%-4.00mol%, 2.50mol%-3.50mol%, 2.50mol%-3.30mol%, 2.50mol%-3.10mol%, 2.50mol%-3.00mol%, 2.50mol%-2.80mol%, 2.80mol%-3.50mol%, 2.80mol%-3.40mol%, 2.80mol%-3.30mol% or 2.80mol%-3.10mol% ZrO2. In some embodiments, the transparent glass-ceramics or substrate glass may contain 2.00 mol%, 2.50 mol%, 2.70 mol%, 2.90 mol%, 3.00 mol%, 3.10 mol%, 3.30 mol%, 3.50 mol%, or 4.00 mol% of ZrO2, or may contain ZrO2 within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired performance of the present application can be obtained.

[0144] In the present application, an appropriate amount of B2O3 helps to lower the melting temperature of the base glass. B2O3 has boron oxide triangles [BO3] and boron oxide tetrahedrons [BO4] as structural units. As the B2O3 content increases, the relative content of boron oxide triangles and boron oxide tetrahedrons changes, resulting in a reversal of structure and properties. When too much B2O3 is added, on the one hand, the three-dimensional framework-like structure of the boron oxide tetrahedron [BO4] is transformed into a two-dimensional layered structure of the boron oxide triangle [BO3]. The three-coordinated boron oxide triangle [BO3] is not as strong as the boron oxide tetrahedron [BO4], which will have the effect of opening the network structure. At the same time, the increase in the B2O3 content in the residual glass phase will reduce the viscosity of the residual glass phase and promote the growth of crystals such as lithium silicate. On the other hand, the base glass is more likely to precipitate SiO2 crystal phases (such as cristobalite), which will affect the transmittance of the glass and also deteriorate the overall uniformity of the glass brick. In the present application, the transparent microcrystalline glass or substrate glass contains 0.00 mol%-1.00 mol% of B2O3. B2O3 that meets this content range helps to lower the melting temperature of the substrate glass and improve the transmittance, overall uniformity and other properties of the microcrystalline glass.

[0145] In some embodiments, the transparent microcrystalline glass or substrate glass may contain 0.00mol%-1.00mol%, 0.00mol%-0.90mol%, 0.00mol%-0.80mol%, 0.00mol%-0.70mol%, 0.00mol%-0.60mol%, 0.00mol%-0.50mol%, 0.00mol%-0.40mol%, 0.20mol%-1.00mol%, 0.30mol%-0.80mol% or 0.30mol%-0.50mol% B2O3. In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.00 mol%, 0.10 mol%, 0.20 mol%, 0.30 mol%, 0.40 mol%, 0.50 mol%, 0.70 mol%, 0.90 mol% or 1.00 mol% of B2O3, or may contain B2O3 within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired performance of the present application can be obtained.

[0146] In the present application, Na2O and K2O are oxides outside the glass network, which can provide free oxygen and increase the oxygen-silicon ratio in the glass structure. Therefore, excessive Na2O and K2O will affect the network structure of the glass, affecting the optical properties, thermal stability, chemical stability, mechanical strength and weather resistance of the glass. However, in the present application, an appropriate amount of Na2O and K2O can bring certain beneficial effects. For example, an appropriate amount of Na2O can play a role in regulating grain size, promoting crystallization of lithium silicate structure, and reducing the crystallization tendency of the substrate glass, thereby appropriately increasing the transmittance of the microcrystalline glass, and appropriately improving the thermal stability, chemical stability, mechanical strength, weather resistance, etc. of the microcrystalline glass. Therefore, in the present application, it is preferred that the transparent microcrystalline glass or substrate glass contain 0.00mol%-1.00mol% of Na2O and 0.00mol%-0.50mol% of K2O.

[0147] In some embodiments, the transparent microcrystalline glass or substrate glass may contain 0.00mol%-1.00mol%, 0.00mol%-0.90mol%, 0.00mol%-0.80mol%, 0.00mol%-0.70mol%, 0.00mol%-0.60mol%, 0.00mol%-0.50mol%, 0.00mol%-0.40mol%, 0.20mol%-1.00mol%, 0.30mol%-0.80mol% or 0.30mol%-0.50mol% of Na2O. In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.00 mol%, 0.10 mol%, 0.20 mol%, 0.30 mol%, 0.40 mol%, 0.50 mol%, 0.70 mol%, 0.90 mol%, or 1.00 mol% of Na2O, or may contain Na2O within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges may be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired properties of the present application is obtained.

[0148] In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.00mol%-0.50mol%, 0.00mol%-0.40mol%, 0.00mol%-0.30mol%, 0.00mol%-0.20mol%, 0.00mol%-0.10mol%, 0.10mol%-0.50mol% or 0.20mol%-0.40mol% of K2O. In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.00mol%, 0.10mol%, 0.20mol%, 0.30mol%, 0.40mol% or 0.50mol% of K2O, or may contain K2O within a numerical range consisting of any two of the above specific numerical values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the required performance of the present application can be obtained.

[0149] In the present application, an appropriate amount of CaO is beneficial to increasing the chemical stability and mechanical strength of the glass, reducing the viscosity of the glass, enhancing the meltability and formability of the glass, and also helping to adjust the thermal expansion coefficient and refractive index of the glass-ceramics. However, when the CaO content is too high, the glass is prone to devitrification after crystallization. Excessive CaO residue in the glass phase creates a refractive index difference with the main crystal phase, which will lead to a decrease in the transmittance of the glass-ceramics and an increase in the haze. In the present application, the transparent glass-ceramics or substrate glass contains 0.00 mol% to 1.60 mol% of CaO.

[0150] In some embodiments, the transparent microcrystalline glass or substrate glass may contain 0.00mol%-1.60mol%, 0.50mol%-1.60mol%, 0.50mol%-1.50mol%, 0.50mol%-1.30mol%, 0.50mol%-1.20mol%, 0.50mol%-1.00mol%, 0.50mol%-0.85mol%, 0.85mol%-1.40mol%, 0.85mol%-1.30mol%, 0.85mol%-1.20mol%, 0.85mol%-1.10mol%, 0.85mol%-1.00mol% or 1.00mol%-1.30mol% of CaO. In some embodiments, the transparent glass-ceramics or substrate glass may contain 0.00 mol%, 0.50 mol%, 0.70 mol%, 0.85 mol%, 0.95 mol%, 1.00 mol%, 1.10 mol%, 1.20 mol%, 1.30 mol%, 1.40 mol%, 1.50 mol%, or 1.60 mol% of CaO, or may contain CaO within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired performance of the present application can be obtained.

[0151] In the present application, the composition of the transparent glass-ceramics or substrate glass, expressed as a molar percentage of each oxide in the composition of the transparent glass-ceramics or substrate glass, satisfies the following conditions: 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000, where the chemical formula represents the molar percentage of the oxide, which is conducive to the mass production of large-sized transparent glass-ceramics with satisfactory optical properties. In some embodiments, the value of 2×Li2O / (0.5×ZrO2+CaO) can be, for example, 14.000, 15.000, 16.000, 17.000, 18.000, 19.000, 20.000, 21.000, 22.000, or 23.000, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in a specific embodiment, any of the above ranges can be combined with any other ranges, as long as the transparent microcrystalline glass or substrate glass with the required performance of the present application can be obtained.

[0152] In some embodiments, the composition of the transparent glass-ceramics or substrate glass, expressed in terms of the molar percentage of each oxide in the composition, satisfies: 4.100≤(Li2O+Na2O+K2O+B2O3) / (P2O5+ZrO2+CaO)≤6.000, where the chemical formula represents the molar percentage of the oxide, thereby facilitating the formation of a transparent glass-ceramics that meets a specific structure and has excellent performance (especially optical and strength performance). In some embodiments, the value of (Li2O+Na2O+K2O+B2O3) / (P2O5+ZrO2+CaO) can be, for example, 4.100, 4.200, 4.300, 4.400, 4.500, 4.600, 4.700, 4.800, 4.900, 5.000, 5.100, 5.200, 5.300, 5.400, 5.500, 5.600, 5.700, 5.800, 5.900, or 6.000, or any value between these adjacent values, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired properties of the present application can be obtained.

[0153] In some embodiments, the composition of the transparent glass-ceramics or substrate glass, expressed in terms of the molar percentage of each oxide in the composition, satisfies the following conditions: 0.100≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900, preferably 0.190≤P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3)≤0.900, where the chemical formula represents the molar percentage of the oxide, thereby facilitating the formation of a transparent glass-ceramics that meets a specific structure and has excellent performance (especially optical and strength performance). In some embodiments, the value of P2O5×(CaO+ZrO2+Li2O+Al2O3) / (Na2O+K2O+B2O3) can be, for example, 0.100, 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, or 0.900, or can be a value within a numerical range defined by any two of the aforementioned specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the aforementioned ranges can be combined with any other ranges, as long as the transparent glass-ceramics or substrate glass having the desired properties is obtained.

[0154] In some embodiments, the transparent glass-ceramics or substrate glass comprises, by mole percentage of oxides, SiO2: 67.50 mol% to 71.00 mol%, Al2O3: 3.50 mol% to 5.00 mol%, P2O5: 0.85 mol% to 1.50 mol%, ZrO2: 2.50 mol% to 3.50 mol%, Na2O: 0.00 mol% to 1.00 mol%, K2O: greater than 0.00 mol% and not greater than 0.50 mol%, Li2O: 20.00 mol% to 25.00 mol%, CaO: greater than 0.50 mol% and not greater than 1.60 mol%, and B2O3: 0.00 mol% to 1.00 mol%. Adjusting the content of the necessary oxides can further improve the network structure of the glass-ceramics, thereby ensuring large-scale mass production of the transparent glass-ceramics and ensuring the excellent optical and strength properties of the mass-produced products.

[0155] In some embodiments, the transparent glass-ceramics does not contain a quartz crystal phase. In a glass-ceramics whose main crystal phases are petalite crystal phase and lithium disilicate crystal phase, if a quartz crystal phase is precipitated, the transmittance of the glass-ceramics will be reduced, affecting the optical properties of the glass-ceramics. It will also easily deteriorate the overall uniformity of the glass-ceramics bricks, leading to large differences in b-values ​​in different areas of the glass, and problems such as flowery pieces. In some embodiments, the crystallinity of the transparent glass-ceramics is ≥70.00wt%, preferably, ≥80.00wt%. The "crystallization degree of the transparent glass-ceramics" here refers to the percentage of the content of all crystalline phases / crystals in the glass-ceramics to the mass of the glass-ceramics. A higher content of microcrystalline phase is beneficial to improving the mechanical strength properties of the glass-ceramics. In some embodiments, the crystallinity of the transparent glass-ceramics may be 70.00 wt%, 75.00 wt%, 80.00 wt%, 85.00 wt%, 90.00 wt%, 93.00 wt%, 95.00 wt%, 98.00 wt% or 100.00 wt%, or may be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges may be combined with any other ranges, as long as the transparent glass-ceramics having the desired properties of the present application can be obtained.

[0156] In some embodiments, in the transparent glass-ceramics, the average crystal size does not exceed 100 nm. Meeting a smaller average crystal size is conducive to ensuring the excellent optical properties of the glass-ceramics. In some embodiments, the average crystal size can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the performance required by the present application can be obtained.

[0157] In some embodiments, in the transparent glass-ceramics, the petalite crystalline phase accounts for 35.00wt%-50.00wt% of the mass of the transparent glass-ceramics, and the lithium disilicate crystalline phase accounts for 35.00wt%-50.00wt% of the mass of the transparent glass-ceramics. In some embodiments, the percentage of the petalite crystalline phase in the mass of the transparent glass-ceramics can be 35.00wt%-50.00wt%, 35.00wt%-45.00wt%, 35.00wt%-40.00wt%, or 40.00wt%-50.00wt%. In some embodiments, the transparent glass-ceramics may include 35.00wt%, 40.00wt%, 45.00wt%, or 50.00wt% of the petalite crystalline phase, or may include the petalite crystalline phase within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in a specific embodiment, any of the above ranges can be combined with any other ranges, as long as the transparent microcrystalline glass with the required performance of the present application can be obtained.

[0158] In some embodiments, the percentage of the lithium disilicate crystalline phase in the mass of the transparent glass-ceramics can be 35.00wt%-50.00wt%, 35.00wt%-45.00wt%, 35.00wt%-40.00wt% or 40.00wt%-50.00wt%. In some embodiments, the transparent glass-ceramics may include 35.00wt%, 40.00wt%, 45.00wt% or 50.00wt% of the lithium disilicate crystalline phase, or may include the lithium disilicate crystalline phase within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics having the desired performance of the present application can be obtained.

[0159] By adjusting the petalite crystal phase and the lithium disilicate crystal phase to meet a suitable ratio, it is beneficial to form a specific microstructure, which in turn helps to ensure that the microcrystalline glass has high mechanical strength and fracture toughness.

[0160] In some embodiments, the transparent glass-ceramics contains one or more of a lithium silicate (Li2SiO3) crystal phase, a lithium phosphate (Li3PO4) crystal phase, and a spodumene crystal phase as a secondary crystalline phase. In some embodiments, in the transparent glass-ceramics, the secondary crystalline phase accounts for less than 30.00wt% of the mass of the transparent glass-ceramics, and preferably the secondary crystalline phase accounts for less than 10.00wt% of the mass of the transparent glass-ceramics. In the transparent glass-ceramics of the present application, the secondary crystalline phase content is low, which is more conducive to ensuring a high content of the main crystalline phase, and thus ensuring the excellent mechanical strength properties of the glass-ceramics. In some embodiments, the percentage of the secondary crystalline phase in the mass of the transparent glass-ceramics can be 0wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt% or 30.00wt%, or can be a value within the numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the required performance of the present application can be obtained.

[0161] In some embodiments, in the transparent glass-ceramics, a lithium silicate crystal phase accounts for less than 5.00 wt% of the mass of the transparent glass-ceramics, and the total amount of the lithium phosphate crystal phase and the spodumene crystal phase accounts for less than 5.00 wt% of the mass of the transparent glass-ceramics.

[0162] In some embodiments, when the length, width and thickness specifications of the transparent microcrystalline glass are (200mm-500mm)×(100mm-500mm)×(10mm-40mm), the range of the b value at nine locations on the main surface of the transparent microcrystalline glass is ≤2.00, preferably ≤1.50, and more preferably ≤1.00. The "range of the b value at nine locations" here refers to the difference between the maximum and minimum b values ​​at nine locations tested on the main surface of the glass. In some embodiments, the range of the b value at nine locations on the main surface of the transparent microcrystalline glass under this specification can be 0, 0.10, 0.50, 0.80, 1.00, 1.20, 1.50, 1.70, 1.80, 1.90 or 2.00, or can be a value within the numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in a specific embodiment, any of the above ranges can be combined with any other ranges, as long as the transparent microcrystalline glass with the required performance of this application can be obtained. The smaller the range of the b values ​​at the nine points on the main surface of the microcrystalline glass that meets this specification, the better the overall uniformity and optical effect of the microcrystalline glass of the present application when it is produced to this specification, which is conducive to ensuring that the cut microcrystalline glass sheets meet the excellent optical performance requirements and display effect requirements.

[0163] In some embodiments, when the length, width and thickness specifications of the transparent glass-ceramics are (45mm-450mm)×(45mm-350mm)×(0.4mm-2.0mm), the range of the b values ​​at nine locations on the main surface of the transparent glass-ceramics is ≤0.30, preferably ≤0.10, preferably ≤0.06. In some embodiments, the range of the b values ​​at nine locations on the main surface of the transparent glass-ceramics under this specification can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.20 or 0.30, or can be a value within the numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the required performance of the present application can be obtained. The smaller the range of the nine b values ​​on the main surface of the microcrystalline glass sheet of this specification, the better the overall uniformity of the microcrystalline glass sheet of this application and the better the overall display effect.

[0164] The nine locations are: (1) four test locations of test circle I that is tangent to the long side and the adjacent short side of the main surface; (2) four test locations of test circle II formed by the point on the line segment formed by the centers of the four test circles I that is closest to the middle of the long side or short side of the main surface; (3) one test circle III formed by the center point of the main surface as the center, as shown in Figure 13. Combined with the aforementioned b-value test method, it can be seen that each test location is a circle with a test aperture, and the center of the circle coincides with the above-mentioned test circle I, test circle II, or test circle III.

[0165] In some embodiments, when the thickness of the transparent glass-ceramics is 0.6 mm, the b-value is ≤1.00, preferably the b-value is ≤0.70, the haze is ≤0.25%, preferably the haze is ≤0.18%, and the transmittance of the transparent glass-ceramics is ≥90.00% under a wavelength of 550 nm. In some preferred embodiments, when the thickness of the transparent glass-ceramics is 0.6 mm, the b-value is ≤0.60, the haze is ≤0.16%, and the transmittance of the transparent glass-ceramics is ≥90.50% under a wavelength of 550 nm. The higher the transmittance and the smaller the b-value and haze, the better the optical properties of the glass-ceramics.

[0166] In some embodiments, the transmittance of a 0.6 mm thick transparent glass-ceramics under 550 nm wavelength light can be 90.00%, 90.50%, 91.00%, 92.00%, 93.00%, 94.00%, 95.00%, 96.00%, 97.00%, 98.00%, 99.00% or 100.00%, or can be a value within the numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in a specific embodiment, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the required performance of the present application can be obtained. In some embodiments, the b value of a 0.6 mm thick transparent glass-ceramics can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.0, or can be a value within the numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the desired performance of the present application can be obtained. In some embodiments, the haze of a 0.6 mm thick transparent glass-ceramics can be 0, 0.01%, 0.05%, 0.08%, 0.10%, 0.12%, 0.14%, 0.16%, 0.18%, 0.20% or 0.25%, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the transparent glass-ceramics with the desired performance of the present application can be obtained.

[0167] As described above, the extreme difference of the b-values ​​at nine locations on the main surface of the transparent microcrystalline glass of the present application is small, that is, the b-values ​​in different areas of the transparent microcrystalline glass of the present application are close; the transparent microcrystalline glass of the present application has high transmittance, low b-value, and low haze, which all indicate that the optical properties of the transparent microcrystalline glass of the present application are excellent and uniform, and can meet the application requirements of display screen cover plates.

[0168] In some embodiments, according to a simultaneous thermal analysis test, under a protective atmosphere of nitrogen, the substrate glass is heated from room temperature to 900°C at a heating rate of 10°C / min to obtain a heating DSC curve. In the heating DSC curve, there are at least two exothermic peaks, wherein the first exothermic peak temperature T1 is 600°C-730°C, and the second exothermic peak temperature T2 is 740°C-800°C, and T1 and T2 satisfy the relationship: 100°C ≥ T2-T1 ≥ 40°C, preferably 80°C ≥ T2-T1 ≥ 50°C.

[0169] In some embodiments, according to a simultaneous thermal analysis test, the substrate glass is heated from room temperature to 1400°C at a heating rate of 10°C / min and kept warm for 10 minutes under a nitrogen protective atmosphere, and then cooled from 1400°C to 450°C at a cooling rate of 10°C / min to obtain a cooling DSC curve. In the cooling DSC curve, in the range of 500°C-900°C, the sum of the integrated areas of the exothermic peaks and endothermic peaks contained therein is S≤10, preferably there is no endothermic peak and / or no exothermic peak, and more preferably S=0.

[0170] Large-sized substrate glass bricks made of a specific substrate glass solution that meets specific DSC curve characteristics (including specific heating DSC curve characteristics and specific cooling DSC curve characteristics) are heat-treated under the production line process conditions for mass production of microcrystalline glass to produce transparent microcrystalline glass bricks whose optical properties and display effects meet the requirements for display screens. This can effectively solve the problems of glass brick cracking, large differences in b-values ​​in different areas of glass bricks, localized undesirable colors, spots, poor display, and other problems that are prone to occur during mass production of microcrystalline glass bricks in the prior art. Therefore, before preparing large-sized microcrystalline glass bricks, glass samples can be made according to the glass formula. By obtaining the DSC curve characteristics, it is first verified whether the glass solution is suitable for the production of large-sized, especially thick, qualified microcrystalline glass products. If it does not meet the requirements, it can be adjusted in a timely manner until it meets the specific DSC curve characteristics before the preparation of large-sized products. This can greatly save time and cost and effectively avoid waste of resources.

[0171] In some embodiments, the substrate glass is heated from room temperature to T at a heating rate of 10°C / min. 1-30 Temperature, and keep it at this temperature for 240 minutes for treatment, and the content of quartz crystal phase in the product obtained after treatment is less than 15wt%; wherein, T 1-30 =T1-30℃.

[0172] In some embodiments, the substrate glass is heated from room temperature to T at a heating rate of 10°C / min. 1-60 Temperature, and keep it at this temperature for 240 minutes for treatment, wherein the content of quartz crystal phase in the product obtained after treatment is less than 5wt%, preferably no quartz crystal phase; wherein T 1-60 =T1-60℃.

[0173] In T 1-30 and / or T 1-60 The substrate glass that meets the specific quartz crystal phase content requirements after heat treatment at a certain temperature can effectively avoid the precipitation of quartz crystal phase in the target microcrystalline glass bricks that affects the optical properties of the microcrystalline glass when the target microcrystalline glass is prepared by heat treatment, thereby ensuring the large-scale production of large-size transparent microcrystalline glass bricks that meet the use requirements.

[0174] The preparation method or forming method of the substrate glass of the present application includes but is not limited to the float method, overflow method, rolling method, casting method or continuous melting method. In order to improve the yield, the present application preferably adopts the continuous melting method to prepare the substrate glass. The continuous melting method refers to a melting method with continuous feeding and continuous furnace discharge. Specifically, the raw materials can be continuously fed into the melting furnace through an automatic feeding device, heated to 1500℃-1600℃, melted for 24-72 hours, and then pulled into shape, continuously drawn and cut into substrate glass products of any length.

[0175] The method for preparing the transparent microcrystalline glass of the present application comprises: heat-treating the substrate glass as described above to obtain the transparent microcrystalline glass. The heat treatment conditions of the present application can be selected from a wide range of conditions, and those skilled in the art can select from the existing technologies according to actual needs.

[0176] In some embodiments, the heat treatment includes a nucleation treatment and a crystallization treatment, wherein the temperature of the nucleation treatment is (Tg-20°C) to (Tg+40°C), for example, (Tg-20°C), (Tg-15°C), (Tg-10°C), (Tg-5°C), (Tg-2°C), Tg, (Tg+2°C), (Tg+5°C), (Tg+10°C), (Tg+15°C), or (Tg+40°C), or any value between these adjacent values. Tg is the glass transition temperature of the substrate glass.

[0177] In some embodiments, the time of the nucleation treatment is 0 min-6000 min, for example, it can be 0 min, 30 min, 50 min, 70 min, 100 min, 130 min, 150 min, 180 min, 200 min, 250 min, 280 min, 300 min, 330 min, 360 min, 600 min, 800 min, 900 min, 1500 min, 2000 min or 6000 min, or any value between these adjacent point values.

[0178] In some embodiments, the temperature of the crystallization treatment is (T1-20°C) to (T1+20°C), for example, it can be (T1-20°C), (T1-15°C), (T1-10°C), (T1-5°C), (T1-2°C), T1, (T1+2°C), (T1+5°C), (T1+10°C), (T1+15°C) or (T1+20°C), or any value between these adjacent point values.

[0179] In some embodiments, the crystallization treatment time is 30 min-6000 min, for example, it can be 30 min, 50 min, 70 min, 100 min, 130 min, 150 min, 180 min, 200 min, 250 min, 280 min, 300 min, 330 min, 360 min, 400 min, 450 min, 500 min, 550 min, 600 min, 1000 min, 2000 min, 3000 min, 4000 min, 5000 min or 6000 min, or any value between these adjacent point values.

[0180] In some embodiments, the heating rate of the heat treatment process is 5-15°C / min, for example, 5°C / min, 8°C / min, 10°C / min, 12°C / min, 14°C / min or 15°C / min, or any value between these adjacent point values.

[0181] It should be understood that, in the present application, the nucleation treatment is to raise the temperature to the prescribed nucleation treatment temperature (also called the nucleation temperature), and after reaching the nucleation treatment temperature, keep the temperature for a certain period of time, the holding time here is the nucleation treatment time (also called the nucleation time). The crystallization treatment is to raise the temperature to the prescribed crystallization treatment temperature (also called the crystallization temperature), and after reaching the crystallization treatment temperature, keep the temperature for a certain period of time, the holding time here is the crystallization treatment time (also called the crystallization time). The use of the above-mentioned heat treatment conditions is conducive to the production of a transparent microcrystalline glass product with a specific and uniform microstructure, with petalite crystal phase and lithium disilicate crystal phase as the main crystal phases, and excellent optical and mechanical properties.

[0182] In some embodiments, the process of preparing transparent microcrystalline glass of the present application also includes a process of cold working the transparent microcrystalline glass (brick) obtained by heat treating the substrate glass to obtain transparent microcrystalline glass of the desired specifications and dimensions (e.g., a thickness of 0.2 mm to 2.0 mm). The cold working treatment here includes shaping treatment, slicing treatment, CNC treatment, grinding treatment, polishing treatment, etc. commonly used in the art. Those skilled in the art can select one or more of the above methods to perform cold working on the transparent microcrystalline glass according to actual needs.

[0183] The present application provides a chemically strengthened glass-ceramic, wherein the chemically strengthened glass-ceramic is obtained by subjecting the transparent glass-ceramic described above to a chemical strengthening treatment. The composition at the center of the chemically strengthened glass-ceramic is substantially the same as that of the transparent glass-ceramic, the chemically strengthened glass-ceramic includes a compressive stress layer region extending from the surface of the transparent glass-ceramic to a compression depth, and has tensile stress within the chemically strengthened glass-ceramic.

[0184] After chemical strengthening treatment, it should be understood that the composition at the surface of the glass-ceramics may be different from the composition of the newly formed glass-ceramics (i.e., glass-ceramics that have not been chemically strengthened). This is because during the chemical strengthening treatment, ion exchange occurs, and one type of alkali metal ion (e.g., Li + Or Na + ) are respectively replaced by larger alkali metal ions (e.g., Na + or K + ) is replaced by, such as Na in glass-ceramics + K in molten salt bath + Exchange, K + Replaced by, and / or, Li in glass-ceramics + With Na in molten salt bath + Exchange, by Na + However, in the embodiment, the composition and phase assembly of the glass-ceramic at the center of the depth of the glass product or near the center of the depth will still have the composition and phase assembly of the newly formed glass-ceramic. That is, in the chemically strengthened glass-ceramic of the present application, the composition of the compressive stress layer formed by ion exchange on the surface may be different from the composition of the unstrengthened glass-ceramic, while the composition of the tensile stress layer with tensile stress (also called tensile stress) inside or the composition at the center of the glass-ceramic will still have the composition of the unstrengthened glass-ceramic.

[0185] The chemical strengthening treatment conditions described in this application have a wide range of optional conditions, and those skilled in the art can select them according to actual needs. In some embodiments, the chemical strengthening treatment salt bath is a mixed molten salt, and the composition of the mixed molten salt includes: 0 < NaNO3 < 100wt%, 0 < KNO3 < 100wt%, and 0 < LiNO3 ≤ 0.2wt%.

[0186] In various embodiments, based on the total amount of NaNO3 and KNO3 in the mixed molten salt, the mixed molten salt contains 0<NaNO3<100wt%. For example, the mixed molten salt may contain 20wt%-50wt%, 10wt%-50wt%, 10wt%-40wt%, 20wt%-40wt%, 20wt%-90wt%, or 40wt%-90wt% NaNO3. In various embodiments, based on the total amount of NaNO3 and KNO3 in the mixed molten salt, the mixed molten salt contains 0<KNO3<100wt%. For example, the mixed molten salt may contain 20wt%-50wt%, 10wt%-50wt%, 10wt%-40wt%, 20wt%-40wt%, 20wt%-90wt%, or 40wt%-90wt% KNO3. In various embodiments, based on the total amount of NaNO3 and KNO3 in the mixed molten salt, the mixed molten salt further contains 0<LiNO3≤0.2wt%. For example, the mixed molten salt may contain 0.01 wt%-0.20 wt%, 0.01 wt%-0.18 wt%, 0.01 wt%-0.15 wt%, 0.01 wt%-0.10 wt%, or 0.01 wt%-0.05 wt% of LiNO3.

[0187] In some embodiments, the temperature of the salt bath for chemical strengthening treatment is 430° C.-530° C., and the time of the chemical strengthening treatment is 0.5 h-15.0 h.

[0188] The use of the above-mentioned strengthening process for chemical strengthening is beneficial to improving the chemical strengthening efficiency while ensuring that the chemically strengthened glass-ceramics obtains a desired stress level.

[0189] In some embodiments, the temperature of the chemical strengthening salt bath may be 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, or 530°C, or may be a value within a numerical range consisting of any two of the above specific values ​​as endpoints.

[0190] In some embodiments, the time of the chemical strengthening treatment can be 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, 5.0 h, 6.0 h, 7.0 h, 8.0 h, 9.0 h, 10.0 h, 11.0 h, 12.0 h, 13.0 h, 14.0 h or 15.0 h, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints.

[0191] In some embodiments, the surface Na2O concentration of the chemically strengthened glass-ceramics is 5.0wt%-20.0wt%. For example, the surface Na2O concentration of the chemically strengthened glass-ceramics can be 5.0wt%, 6.0wt%, 7.0wt%, 8.0wt%, 9.0wt%, 10.0wt%, 11.0wt%, 12.0wt%, 13.0wt%, 14.0wt%, 15.0wt%, 16.0wt%, 17.0wt%, 18.0wt%, 19.0wt% or 20.0wt%, or can be a value within a numerical range consisting of any two of the above specific values ​​as endpoints. By meeting the surface Na2O concentration within the above range, it is possible to ensure that the chemically strengthened glass-ceramics has a better surface stress level and also ensure that the chemically strengthened glass-ceramics has better weather resistance and chemical durability.

[0192] In some embodiments, the chemically strengthened glass-ceramics has a CS_50 of 110-200 MPa, where CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramics. For example, the chemically strengthened glass-ceramics has a CS_50 of 110-200 MPa, 110-180 MPa, 110-160 MPa, 110-150 MPa, 110-130 MPa, 130-180 MPa, or 130-150 MPa. The CS_50 range of the chemically strengthened glass-ceramics is within the above range, indicating that the chemically strengthened glass-ceramics has a high compressive stress at a depth of 50 μm from the surface, indicating that the chemically strengthened glass-ceramics has a higher surface stress level. The higher the surface compressive stress level, the more residual energy of the drop collision can be offset, thereby ensuring its excellent damage resistance. In some embodiments, the chemically strengthened glass-ceramics have a |CT_AV| of 84-140 MPa, where |CT_AV| refers to the absolute value of the average tensile stress. For example, the chemically strengthened glass-ceramics have a |CT_AV| of 84-140 MPa, 85-140 MPa, 85-120 MPa, 85-100 MPa, 90-140 MPa, 100-140 MPa, or 120-140 MPa. A |CT_AV| of the chemically strengthened glass-ceramics within the above ranges indicates that the chemically strengthened glass-ceramics have a higher tensile stress level, reflecting a higher surface stress level. A higher surface compressive stress level can offset more residual energy from a drop collision, thereby ensuring excellent damage resistance.

[0193] In some embodiments, the compressive stress layer depth DOL_0 of the chemically strengthened glass-ceramics is 0.18t-0.25t, where t is the thickness of the chemically strengthened glass-ceramics. For example, the compressive stress layer depth DOL_0 of the chemically strengthened glass-ceramics can be 0.18t-0.25t, 0.18t-0.22t, 0.18t-0.20t, 0.20t-0.25t, or 0.22t-0.25t. Exemplarily, when the thickness of the chemically strengthened glass-ceramics is 0.6mm, the DOL_0 of the chemically strengthened glass-ceramics can be 0.108mm, 0.120mm, 0.130mm, 0.140mm, 0.145mm, or 0.150mm. The DOL_0 of the chemically strengthened glass-ceramics is within the above range, indicating that the chemically strengthened glass-ceramics has a high compressive stress layer depth, which is more conducive to offsetting the energy that drives crack propagation, thereby ensuring that it has excellent damage resistance.

[0194] Meeting specific stress characteristics can ensure that chemically strengthened glass-ceramics has excellent mechanical strength properties, especially excellent drop resistance.

[0195] In some embodiments, the chemically strengthened glass-ceramics having a thickness of 0.6 mm was subjected to multiple fixed-point height drop tests using 120-grit sandpaper. The fixed-point height of the test was 1.0 m. The chemically strengthened glass-ceramics broke 30 or more times, preferably 50 or more. This indicates that the chemically strengthened glass-ceramics of the present application have excellent drop resistance.

[0196] The transparent glass-ceramics or chemically strengthened glass-ceramics with excellent optical and mechanical properties provided by the present application can be used in any desired glass-ceramics glass device and can be used in many applications. For example, work surfaces, other surfaces, covers of electronic devices or electronic devices, appliance doors, floor tiles, wall panels, storage containers, etc. Other surfaces may include but are not limited to exterior wall surfaces, stair tread surfaces, column veneers, counter surfaces, etc. The types of electronic devices or electronic devices may include but are not limited to handheld, desktop-mounted, and wall-mounted, etc. Covers may include but are not limited to mobile phone covers, mobile phone back panels, tablet computer covers, etc. Storage containers may include but are not limited to plates, beverage bottles, etc.

[0197] In some embodiments of the present application, the transparent glass-ceramics or chemically strengthened glass-ceramics can be 2D, 2.5D, 3D, or a special shape; and / or, the transparent glass-ceramics or chemically strengthened glass-ceramics can be of uniform or unequal thickness. Those skilled in the art can make this choice based on their needs. "Unequal thickness" here means that the transparent glass-ceramics or chemically strengthened glass-ceramics contains at least two portions of different thicknesses.

[0198] The embodiments of the present application are described in detail below. These embodiments are exemplary and are only used to explain the present application. They should not be construed as limiting the present application.

[0199] In the example numbers of the following tables, S refers to an embodiment, such as S1 refers to Example 1; D refers to a comparative example, such as D1 refers to Comparative Example 1.

[0200] Example 1

[0201] (1) Preparation of substrate glass: The substrate glass is produced using a continuous melting method. The raw materials are prepared according to the ratio of each oxide in S1 of Table 1. After mixing, they are continuously fed into a melting furnace through an automatic feeding device, heated to 1600°C, melted for 24 hours, and then pulled into shape. The substrate glass (brick) product is continuously drawn and cut into the required specifications. For example, the substrate glass (brick) can be cut into a molded size of 360 mm (length) × 180 mm (width) × 30 mm (thickness).

[0202] Test results of the substrate glass obtained in S1:

[0203] Ⅰ. Through observation, the substrate glass prepared in S1 is overall clear and transparent.

[0204] II. Measure the Tg, heating DSC curve, and cooling DSC curve of the substrate glass in S1. Record the first exothermic peak temperature T1, the second exothermic peak temperature T2, and their difference in the heating DSC curve. Calculate the integrated area S of the exothermic and endothermic peaks in the cooling DSC curve within the range of 500°C-900°C, as shown in Table 3, Figure 1, and Figure 3, respectively. Table 2 shows the calculated relationship between the oxide contents in Table 1.

[0205] III. The substrate glass prepared in S1 was heated from room temperature to T at a heating rate of 10°C / min. 1-30 Temperature and T 1-60 temperature, and respectively at T 1-30 Temperature and T 1-60 The treatment was carried out by keeping the temperature at 400 °C for 240 min, and the quartz crystal phase content in the product obtained after treatment was tested. The results are shown in Table 3.

[0206] (2) Preparation of glass-ceramics: Using a heat treatment roller kiln line, the base glass was subjected to a heat treatment process to produce glass-ceramics bricks. The heat treatment process is shown in Table 4 and includes a nucleation treatment and a crystallization treatment (referred to as heat treatment process B) performed sequentially. The heating rate during the heat treatment process is 10°C / min. After being removed from the furnace, glass-ceramics bricks are obtained. The composition of the prepared glass-ceramics is the same as that of the base glass in terms of oxide content, as shown in Table 1.

[0207] Test results of the glass-ceramic bricks obtained in S1:

[0208] Ⅰ. Through observation, the microcrystalline glass bricks obtained in S1 are clear and transparent as a whole.

[0209] II. The crystal phase composition, crystal phase content and crystallinity of the glass-ceramics were tested, and the results are shown in Table 4. Calculations show that the average crystal size in the glass-ceramics is 19 nm.

[0210] III. The b values ​​at nine locations on the main surface of the microcrystalline glass with the test size of 360 mm (length) × 180 mm (width) × 30 mm (thickness) are extremely poor. The results are shown in Table 4.

[0211] (3) Cold working the glass-ceramic bricks: The glass-ceramic bricks are subjected to cold working, wherein the cold working comprises shaping, slicing, CNC processing, grinding, and polishing in sequence to obtain glass-ceramic sheets having a size of 170 mm (length) × 80 mm (width) × 0.6 mm (thickness).

[0212] Test results of the glass-ceramic sheet obtained in S1:

[0213] I. The optical properties of the glass-ceramic sheet were tested, including the extreme value of b at nine locations on the main surface of the glass-ceramic sample, the average value of b at nine locations, haze, and transmittance. The test results are shown in Table 4.

[0214] II. XRD diffraction curves at the maximum and minimum b-value locations of the glass-ceramic sheet were measured at nine b-value locations, and a comparison is shown in Figure 15. Figure 15 shows that the crystalline structures at the maximum and minimum b-value locations on the main surface of the glass-ceramic sheet are essentially the same, or have very little difference. This indicates that the glass-ceramic sheet is relatively uniform overall and should provide consistent optical display effects.

[0215] (4) Preparation of chemically strengthened microcrystalline glass: The microcrystalline glass sheet with a size of 170 mm (length) × 80 mm (width) × 0.6 mm (thickness) obtained in step (3) was placed in a mixed nitrate salt bath of 70.00 wt% KNO3 + 30.00 wt% NaNO3 + 0.03 wt% LiNO3 (here, based on the total amount of NaNO3 and KNO3 in the mixed molten salt, the mixed molten salt contains 0.03 wt% LiNO3) at 470°C and treated for 7.0 h to obtain chemically strengthened microcrystalline glass, t = 0.6 mm.

[0216] Test results of chemically strengthened glass-ceramics obtained in S1:

[0217] The chemically strengthened glass-ceramics were tested for drop resistance from a fixed height of 1.0 m using 120-grit sandpaper. The surface NaO concentration, CS50, |CT_AV|, and DOL_0 of the chemically strengthened glass-ceramics were also measured. The test data are shown in Table 5.

[0218] Example 2-Example 28

[0219] The methods are described in Example 1, except that the raw material compositions and corresponding test results of each example are shown in Tables 1 to 5. The transparent glass-ceramics of Examples 2 to 28 all meet the following requirements: the overall appearance is clear and transparent, without cracks; the crystalline phases of the transparent glass-ceramics are mainly Li2Si2O5, LiAlSi4O 10 , there is no quartz crystal phase. According to calculation, the average crystal size of the glass-ceramics of Examples 2 to 28 is between 10 and 50 nm.

[0220] The substrate glass of Example 3 was subjected to heat treatment process A (crystallization temperature is T 1-60 ) is shown in Figure 7. Figure 7 shows that after the substrate glass of Example 3 is subjected to heat treatment process A, the crystalline phases of the product obtained include petalite, lithium disilicate, lithium monosilicate and lithium phosphate crystal phases. The XRD diffraction pattern of the product obtained after the substrate glass of Example 3 is subjected to heat treatment process B is shown in Figure 9, and the crystalline phases are shown in Table 4. The transmittance curve of the microcrystalline glass sheet obtained after the substrate glass of Example 6 is subjected to heat treatment process B when the thickness is 0.6 mm is shown in Figure 17. Among them, the heating DSC curve measured for the substrate glass of Example 22 is shown in Figure 4.

[0221] Comparative Example 1-Comparative Example 13

[0222] The results were carried out in accordance with Example 1, except that the raw material compositions and corresponding test results of each comparative example are shown in Tables 6 to 11. The heating DSC curve of the substrate glass of Comparative Example 1 is shown in FIG5 . The heating DSC curve of the substrate glass of Comparative Example 2 is shown in FIG6 . The substrate glass of Comparative Example 2 was subjected to heat treatment process A (crystallization temperature is T 1-60 ) is shown in Figure 8. The XRD diffraction pattern of the product obtained after the substrate glass of Comparative Example 2 was subjected to heat treatment process B is shown in Figure 10, and the crystal phase is shown in Table 9. The cooling DSC curve of the substrate glass of Comparative Example 4 is shown in Figure 2, and the transmittance curve of the microcrystalline glass sheet with a thickness of 0.6 mm obtained after the substrate glass of Comparative Example 4 was subjected to heat treatment process B is shown in Figure 18.

[0223] In the nine b-value tests of the microcrystalline glass sheet (with flower pieces) of Comparative Example 6, the XRD diffraction curves at the maximum b-value position and the minimum b-value position are compared as shown in Figure 16. It can be seen from the figure that there is an obvious difference in the crystalline phase structure at the maximum b-value position and the minimum b-value position on the main surface of the microcrystalline glass sheet, which indicates that the overall structure of the microcrystalline glass sheet is quite different, which will lead to differences in the overall display effect, resulting in local coloration of the main surface and / or uneven overall coloration. The molten appearance of the base glass of Comparative Example 9 is milky white, as shown in Figure 19. After the base glass bricks of Comparative Example 7 were treated with heat treatment process B, the microcrystalline glass bricks cracked, as shown in Figure 20. Obvious cracks can be seen in the square frame of Figure 20. According to calculations, the average crystal size of the microcrystalline glasses of Comparative Examples 1 to 12 is greater than 20nm.

[0224] Table 1

[0225] Table 2

[0226] Table 3

[0227] Table 4

[0228] Table 5 Note: “>50” in Table 5 means that the material did not break after being dropped 50 times, and the same applies to the other parts; the meanings in the corresponding tables of the comparative examples are the same.

[0229] Table 6

[0230] Table 7

[0231] Table 8

[0232] Table 9

[0233] Table 10

[0234] Table 11

[0235] The results of the embodiments in Tables 1 to 5 and the comparative examples in Tables 6 to 11 above show that, compared to the comparative examples, the embodiment scheme of the present application, while meeting the content ranges of each oxide, also meets the following compositional characteristics: 18.200≤Li2O / P2O5≤25.500; 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. The large-sized substrate glass bricks produced have a clear and transparent appearance. The heating DSC curve of the substrate glass tested by simultaneous thermal analysis shows at least two exothermic peaks at a suitable temperature, and the sum of the integrated areas of the exothermic peaks and the endothermic peaks in the cooling DSC curve is S≤10. The micro-ceramic glass bricks obtained by heat treatment of the substrate glass bricks are all transparent and clear in appearance, and there is no cracking in the micro-ceramic glass bricks. The quartz crystal phase is not contained in the produced micro-ceramic glass phase, and the range of the b value at nine locations on the main surface of the micro-ceramic glass is low. By adopting the embodiment scheme of the present application, large-sized, optically excellent and uniform microcrystalline glass bricks can be mass-produced. At the same time, chemically strengthened microcrystalline glass with excellent optical properties, higher CS_50, |CT_AV|, DOL_0, and excellent drop resistance can be prepared.

[0236] However, in the solutions of Comparative Examples 1 to 8, the formula of the base glass does not simultaneously meet the following requirements: the content range of each oxide in the present application, as well as 18.200≤Li2O / P2O5≤25.500; 14.000≤2×Li2O / (0.5×ZrO2+CaO)≤23.000. After heat treatment to prepare large-sized microcrystalline glass bricks, the optical properties deteriorate (mainly manifested in large differences in b-values ​​in different regions and undesirable colors of the glass bricks) or the bricks are prone to cracking. In the solutions of Comparative Examples 9 and 10, after the preparation of large-sized base glass bricks, milky white precipitates directly appeared in the base glass bricks, the optical properties deteriorated, and the transmittance decreased. In the solutions of Comparative Examples 11 and 12, the mass-produced microcrystalline glass cannot achieve the required excellent mechanical properties after chemical strengthening treatment, and the anti-drop effect is worse than that of the product of the present application. In the solution of Comparative Example 13, milky white precipitates and undissolved matter appeared in the prepared large-sized base glass bricks.

[0237] The preferred embodiments of the present application are described in detail above; however, the present application is not limited thereto. Industrial Applicability

[0238] This application optimizes the glass formula and adopts a glass solution that meets specific composition requirements, especially the oxide content and specific oxide content relationship under specific conditions. It can solve the problem of easy cracking of microcrystalline glass bricks when mass-producing large-sized transparent microcrystalline glass with the main crystal phases being petalite crystal phase and lithium disilicate crystal phase. At the same time, it can ensure that the prepared transparent microcrystalline glass has both excellent optical properties and strength properties, ensuring that its display effect can meet the requirements.

[0239] Among them, the oxide content and the specific oxide content relationship under the specific conditions met by the technical solution of the present application can not only ensure the formation of the main crystalline phases of petalite and lithium disilicate, but also can avoid the problem of overall blueing, fogging, or even cracking of the microcrystalline glass bricks when preparing microcrystalline glass bricks from large-sized substrate glass bricks while ensuring the good melting condition of the substrate glass bricks, which is conducive to the transparent microcrystalline glass obtaining excellent optical properties and strength, thereby enabling the overall display effect of the transparent microcrystalline glass to meet the application requirements of the display cover. At the same time, after chemical strengthening treatment, the transparent microcrystalline glass of the present application can obtain high-strength chemically strengthened microcrystalline glass, which has been verified to have excellent drop resistance.

[0240] Verification shows that, at large sizes, the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics prepared using the technical solution of the present application is ≤2.00; at small sizes, the range of the b-values ​​at nine locations on the main surface of the transparent glass-ceramics prepared using the technical solution of the present application is ≤0.30, preferably ≤0.10. This indicates that, regardless of whether the size is large or small, the b-value differences between different areas of the main surface of the transparent glass-ceramics of the present application are small, the transparent glass-ceramics have good optical properties, and the overall display effect can meet the application requirements of display cover plates. At large sizes, the glass-ceramics can achieve uniform b-values, which helps ensure a high product yield.

[0241] The present application adopts a large-scale base material glass brick made of a specific base material glass solution that meets the specific DSC curve characteristics. Under the production line process conditions of mass production of microcrystalline glass, heat treatment is carried out to produce transparent microcrystalline glass bricks whose optical properties and display effects meet the requirements of display screens. It can well solve the problems of glass brick cracking, large differences in b-values ​​in different areas of glass bricks, localized unexpected colors, spots, poor display, etc. during mass production of microcrystalline glass bricks in the prior art. Therefore, before preparing large-scale microcrystalline glass bricks, glass samples can be melted according to the glass formula. The DSC curve characteristics obtained can be used to pre-verify whether the glass solution is suitable for the production of large-scale microcrystalline glass, especially qualified microcrystalline glass products with large thickness. If it does not meet the requirements, it can be adjusted in time until it meets the specific DSC curve characteristics before the preparation of large-scale products. This can greatly save time and cost and effectively avoid waste of resources.

Claims

1. A transparent glass-ceramic, characterized in that, The transparent glass-ceramics contain spodumene crystal phase and lithium disilicate crystal phase, wherein the spodumene crystal phase and the lithium disilicate crystal phase have a higher weight percentage than other crystal phases present in the transparent glass-ceramics; In terms of the molar percentage of oxides, the composition of the transparent glass-ceramics includes: SiO2: 60.90 mol%-72.65 mol%, Al2O3: 1.50 mol%-5.00 mol%, P2O5: 0.85 mol%-1.50 mol%, ZrO2: 2.00 mol%-4.00 mol%, Na2O: 0.00 mol%-1.00 mol%, K2O: 0.00 mol%-0.50 mol%, Li2O: 20.00 mol%-30.00 mol%, CaO: 0.00 mol%-1.60 mol%, B2O3: 0.00 mol%-1.00 mol%; In terms of the content expressed by the molar percentage of each oxide in the composition of the transparent glass-ceramics, the composition of the transparent glass-ceramics satisfies: 18.200 ≤ Li2O / P2O5 ≤ 25.500; 14.000 ≤ 2×Li2O / (0.5×ZrO2 + CaO) ≤ 23.

000.

2. The transparent glass-ceramics according to claim 1, characterized in that, In terms of the content expressed by the molar percentage of each oxide in the composition of the transparent glass-ceramics, the composition of the transparent glass-ceramics satisfies: 4.100 ≤ (Li2O + Na2O + K2O + B2O3) / (P2O5 + ZrO2 + CaO) ≤ 6.000; and / or, 0.100 ≤ P2O5×(CaO + ZrO2 + Li2O + Al2O3) / (Na2O + K2O + B2O3) ≤ 0.900, preferably, 0.190 ≤ P2O5×(CaO + ZrO2 + Li2O + Al2O3) / (Na2O + K2O + B2O3) ≤ 0.

900.

3. The transparent glass-ceramics according to claim 1 or 2, characterized in that, In terms of the molar percentage of oxides, the composition of the transparent glass-ceramics includes: SiO2: 67.50 mol%-71.00 mol%, Al2O3: 3.50 mol%-5.00 mol%, P2O5: 0.85 mol%-1.50 mol%, ZrO2: 2.50 mol%-3.50 mol%, Na2O: 0.00 mol%-1.00 mol%, K2O: greater than 0.00 mol% and not greater than 0.50 mol%, Li2O: 20.00 mol%-25.00 mol%, CaO: greater than 0.50 mol% and not greater than 1.60 mol%, B2O3: 0.00 mol%-1.00 mol%.

4. The transparent glass-ceramics according to any one of claims 1-3, characterized in that, The transparent glass-ceramics do not contain quartz crystal phase.

5. The transparent glass-ceramics according to any one of claims 1-4, characterized in that, The crystallinity of the transparent glass-ceramics ≥ 70.00 wt%, preferably, the crystallinity ≥ 80.00 wt%; in the transparent glass-ceramics, the average crystal size does not exceed 100 nm.

6. The transparent glass-ceramics according to any one of claims 1-5, characterized in that, In the transparent glass-ceramics, the petalite crystal phase accounts for 35.00 wt% - 50.00 wt% of the mass of the transparent glass-ceramics, and the lithium disilicate crystal phase accounts for 35.00 wt% - 50.00 wt% of the mass of the transparent glass-ceramics.

7. The transparent glass-ceramics according to any one of claims 1-6, characterized in that, The transparent glass-ceramics further contain one or more of the lithium metasilicate crystal phase, the lithium phosphate crystal phase, and the spodumene crystal phase as secondary crystal phases.

8. The transparent glass-ceramics according to claim 7, wherein, In the transparent glass-ceramics, the secondary crystal phase accounts for 30.00 wt% or less of the mass of the transparent glass-ceramics. Preferably, the secondary crystal phase accounts for 10.00 wt% or less of the mass of the transparent glass-ceramics.

9. The transparent glass-ceramics according to any one of claims 1-8, characterized in that, When the length, width, and thickness of the transparent glass-ceramics are (200 mm - 500 mm) × (100 mm - 500 mm) × (10 mm - 40 mm), the range of the b values at nine positions on the main surface of the transparent glass-ceramics is ≤ 2.00, preferably ≤ 1.50, and more preferably ≤ 1.00; Among them, the positions of the nine positions are as follows: (1) The test positions of the test circle I tangent to the long side and the adjacent short side on the main surface, a total of four; (2) The test positions of the four test circles II formed with the points closest to the middle of the long side or the short side of the main surface on the line formed by the centers of the above four test circles I as the center points, a total of four; (3) The position of the test circle III formed with the center point of the main surface as the center.

10. The transparent glass-ceramics according to any one of claims 1-8, characterized in that, When the length, width, and thickness of the transparent glass-ceramics are (45 mm - 450 mm) × (45 mm - 350 mm) × (0.4 mm - 2.0 mm), the range of the b values at nine positions on the main surface of the transparent glass-ceramics is ≤ 0.30, preferably ≤ 0.10, and more preferably ≤ 0.06; Among them, the positions of the nine positions are as follows: (1) The test positions of the test circle I tangent to the long side and the adjacent short side on the main surface, a total of four; (2) The test positions of the four test circles II formed with the points closest to the middle of the long side or the short side of the main surface on the line formed by the centers of the above four test circles I as the center points, a total of four; (3) The position of the test circle III formed with the center point of the main surface as the center.

11. The transparent glass-ceramics according to any one of claims 1-10, characterized in that, When the thickness of the transparent glass-ceramics is 0.6 mm, the b value ≤ 1.00, preferably the b value ≤ 0.70, the haze ≤ 0.25%, preferably the haze ≤ 0.18%. Under the light with a wavelength of 550 nm, the transmittance of the transparent glass-ceramics ≥ 90.00%; Preferably, when the thickness of the transparent glass-ceramics is 0.6 mm, the b value ≤ 0.60, the haze ≤ 0.16%. Under the light with a wavelength of 550 nm, the transmittance of the transparent glass-ceramics ≥ 90.50%.

12. A substrate glass, which can be used to prepare the transparent glass-ceramics as described in any one of claims 1-11 through heat treatment, characterized in that, In terms of the molar percentage of oxides, the composition of the substrate glass includes: SiO2: 60.90 mol% - 72.65 mol%, Al2O3: 1.50 mol% - 5.00 mol%, P2O5: 0.85 mol% - 1.50 mol%, ZrO2: 2.00 mol% - 4.00 mol%, Na2O: 0.00 mol% - 1.00 mol%, K2O: 0.00 mol% - 0.50 mol%, Li2O: 20.00 mol% - 30.00 mol%, CaO: 0.00 mol% - 1.60 mol%, B2O3: 0.00 mol% - 1.00 mol%; Based on the content expressed as the molar percentage of each oxide in the composition of the substrate glass, the composition of the substrate glass satisfies: 18.200 ≤ Li2O / P2O5 ≤ 25.500; 14.000 ≤ 2×Li2O / (0.5×ZrO2 + CaO) ≤ 23.

000.

13. The base glass according to claim 12, characterized in that, Based on the content expressed as the molar percentage of each oxide in the composition of the substrate glass, the composition of the substrate glass satisfies: 4.100 ≤ (Li2O + Na2O + K2O + B2O3) / (P2O5 + ZrO2 + CaO) ≤ 6.000; and / or, 0.100 ≤ P2O5×(CaO + ZrO2 + Li2O + Al2O3) / (Na2O + K2O + B2O3) ≤ 0.900, preferably, 0.190 ≤ P2O5×(CaO + ZrO2 + Li2O + Al2O3) / (Na2O + K2O + B2O3) ≤ 0.

900.

14. The base glass according to claim 12 or 13, characterized in that, Through synchronous thermal analysis test, under the protective atmosphere of nitrogen, the substrate glass is heated from room temperature to 900 °C at a heating rate of 10 °C / min to obtain a heating DSC curve. In this heating DSC curve, there are at least two exothermic peaks, where the temperature T1 of the first exothermic peak is 600 °C - 730 °C, the temperature T2 of the second exothermic peak is 740 °C - 800 °C, and T1 and T2 satisfy the relationship: 100 °C ≥ T2 - T1 ≥ 40 °C, preferably 80 °C ≥ T2 - T1 ≥ 50 °C.

15. The base glass according to any one of claims 12-14, characterized in that, Through synchronous thermal analysis test, the substrate glass is heated from room temperature to 1400 °C at a heating rate of 10 °C / min and held for 10 min under the protective atmosphere of nitrogen, and then cooled from 1400 °C to 450 °C at a cooling rate of 10 °C / min to obtain a cooling DSC curve. In this cooling DSC curve, in the range of 500 °C - 900 °C, the sum S of the integral areas of the exothermic peaks and endothermic peaks contained therein is ≤ 10, preferably there are no endothermic peaks and / or no exothermic peaks, and more preferably S = 0.

16. The base glass according to any one of claims 12-15, characterized in that, Heat the base glass from room temperature to T at a heating rate of 10 °C / min 1-30 temperature, and hold for 240 min at this temperature for treatment. In the product obtained after treatment, the content of the quartz crystal phase is less than 15 wt%, where T 1-30 = T1 - 30 °C; and / or Heat the substrate glass from room temperature to T at a heating rate of 10 °C / min 1-60 temperature, and hold at this temperature for 240 min for treatment. In the product obtained after treatment, the content of quartz crystal phase is less than 5 wt%, preferably without quartz crystal phase, where T 1-60 = T1 - 60 °C.

17. A chemically strengthened microcrystalline glass, characterized in that, The composition at the center of the chemically strengthened glass-ceramics is the same as that of the transparent glass-ceramics described in any one of claims 1 - 11. The chemically strengthened glass-ceramics includes a compressive stress layer and a tensile stress layer.

18. The chemically strengthened glass-ceramics according to claim 17, wherein, The chemically strengthened microcrystalline glass is obtained by chemically strengthening the transparent microcrystalline glass described in any one of claims 1-11. Among them, the salt bath used for the chemical strengthening treatment is a mixed molten salt, and the composition of the mixed molten salt includes: 0 < NaNO3 < 100 wt%, 0 < KNO3 < 100 wt%, and 0 < LiNO3 ≤ 0.2 wt%; the temperature of the salt bath used for the chemical strengthening treatment is 430°C - 530°C, and the time of the chemical strengthening treatment is 0.5 h - 15.0 h.

19. The chemically strengthened glass-ceramics according to any one of claims 17-18, characterized in that, The chemically strengthened microcrystalline glass has a CS_50 of 110 - 200 MPa, where CS_50 refers to the compressive stress value at a depth of 50 μm starting from the main surface of the chemically strengthened microcrystalline glass; and / or The chemically strengthened microcrystalline glass has a |CT_AV| of 84 - 140 MPa, where |CT_AV| refers to the absolute value of the average tensile stress.

20. The chemically strengthened glass-ceramics according to any one of claims 17-19, characterized in that, The depth DOL_0 of the compressive stress layer of the chemically strengthened microcrystalline glass is 0.18t - 0.25t, where t is the thickness of the chemically strengthened microcrystalline glass.

21. The chemically strengthened glass-ceramics according to any one of claims 17-20, characterized in that, Using 120-mesh sandpaper, multiple fixed-point height drop tests are carried out on the chemically strengthened microcrystalline glass with a thickness of 0.6 mm. The fixed-point height of the test is 1.0 m, and the number of times the chemically strengthened microcrystalline glass drops until it breaks is ≥ 30, preferably ≥ 50.

22. A glass device, characterized in that, The glass device includes the transparent microcrystalline glass described in any one of claims 1-11 or includes the chemically strengthened microcrystalline glass described in any one of claims 17-21.

23. An electronic device, characterized in that, The electronic device includes the transparent microcrystalline glass described in any one of claims 1-11 or includes the chemically strengthened microcrystalline glass described in any one of claims 17-21.

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