High-hardness transparent microcrystalline glass, and preparation method and application thereof

Abstract

This invention discloses a high-hardness transparent microcrystalline glass, its preparation method, and its applications. The crystalline phases of the microcrystalline glass include lithium disilicate, lithium phosphate, and at least one of lithium feldspar, β-quartz or their solid solutions, lithium metasilicate, β-spodumene or their solid solutions. It has a grain aspect ratio of 1-30, a transmittance of ≥82% for light with wavelengths of 400-800 nm at a thickness of 1 mm, a Vickers hardness ≥7.7 GPa, and a crystallinity of 50%-85%. The preparation method includes: preparation of a base glass, annealing of the base glass, and heat treatment crystallization. This invention offers strong process controllability, a wide heat treatment process window, and good reproducibility. The prepared microcrystalline glass possesses high transparency, high hardness, high strength, high toughness, and excellent chemical strengthening response characteristics. It can be used as a protective material for mobile phone cover plates, automotive central control screens, robot interactive interfaces, etc., and is suitable for high-end equipment fields such as aircraft portholes.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic materials technology, specifically to a high-hardness transparent microcrystalline glass, its preparation method, and its application. Background Technology

[0002] Glass-ceramics are polycrystalline solid materials obtained through controlled crystallization of base glass, containing both glassy and crystalline phases in their structure. Due to their combination of the ease of forming glass and the excellent mechanical properties of ceramics, glass-ceramics are widely used in optics, electronics, aerospace, and other fields, particularly in applications requiring stringent transparency and mechanical strength, such as mobile phone cover plates, camera protective lenses, optical windows, automotive center console displays, and aircraft windows. These applications demand not only high transparency but also sufficient bending strength, fracture toughness, and impact resistance to meet long-term reliability requirements under complex operating conditions.

[0003] Transparency is one of the core performance indicators of transparent glass-ceramics. According to the theory of light scattering, when the size of the grains inside the material is much smaller than the wavelength of visible light (400~700 nm), the scattering loss of light by the grain boundaries can be effectively reduced, thereby achieving high transparency. Therefore, in order to achieve high light transmittance in transparent glass-ceramics, existing technologies generally follow the design concept of "nanocrystalline grains," controlling the grain size to below 100 nm, or even preferably below 50 nm, and ensuring that the grains are equiaxed to minimize light scattering. For example, CN111635138A discloses a transparent glass-ceramic with a crystal phase of nanoscale equiaxed grains, the grain size of which is in the range of 10~100 nm, exhibiting high transmittance in the visible light band.

[0004] However, while this "nano-equiaxed crystal" design approach improves transparency, it offers limited enhancement to mechanical properties. Since nano-equiaxed crystals exist independently within the glass matrix, they cannot achieve the bridging, pull-out, transgranular fracture, and intergranular crack deflection effects characteristic of high aspect ratio grains (such as long columnar crystals, needle-like crystals, and whiskers). Consequently, the material primarily exhibits brittle fracture characteristics, and its bending strength and fracture toughness are insufficient to meet the demands of high-end applications. For example, mobile phone cover plates are prone to breakage upon drop impact, aircraft windows pose safety hazards under complex loads, and automotive center console screens are susceptible to cracking from impacts during daily use. These issues highlight the limitations of relying solely on nanocrystalline designs in terms of mechanical properties.

[0005] To improve the toughness of glass-ceramics, current technologies often employ post-treatment processes such as ion exchange for chemical strengthening. However, chemical strengthening is a surface modification method applied after material forming, and its reinforcing effect depends on the material's inherent structural basis. If the material's intrinsic toughness is insufficient, relying solely on chemical strengthening is unlikely to achieve a fundamental breakthrough in mechanical properties, and the depth of the strengthening layer and stress distribution are constrained by the material's composition and microstructure. Therefore, how to achieve a synergistic effect between "self-toughening" and subsequent chemical strengthening, starting from the material's intrinsic structure, has become crucial for further improving the overall performance of glass-ceramics.

[0006] Therefore, how to achieve "self-toughening" through the microstructure design of the material itself while maintaining high transparency—that is, obtaining high toughness without introducing external reinforcing phases—has become a pressing technical challenge in this field. How to improve the hardness of the resulting material while maintaining high transparency is also a pressing technical problem. This invention belongs to the field of new materials, specifically relating to a novel inorganic non-metallic material—self-toughened transparent microcrystalline glass. This material possesses high transparency, high hardness, and self-toughening properties, and can be widely used in the manufacturing of new electronic components and high-end equipment. Summary of the Invention

[0007] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a self-toughened transparent microcrystalline glass, its preparation method, products and applications. This invention also provides a high-hardness transparent microcrystalline glass, its preparation method and applications.

[0008] Technical solution: The present invention provides a self-toughened transparent microcrystalline glass, wherein the crystal phase of the microcrystalline glass includes lithium disilicate and lithium phosphate, the average aspect ratio of the microcrystalline glass grains is 1~30, the transmittance of light with wavelengths of 400~800 nm is ≥85% at a thickness of 1 mm, and the crystallinity is 50%~85%.

[0009] Furthermore, the self-toughened transparent microcrystalline glass comprises the following molar percentages of substances: SiO2 58~75 mol%, Li2O 18~30 mol%, P2O5 1.3~3.5 mol%, component A 0.1~8 mol%, component B 1~6 mol%, component C 0~2 mol%, component D 0.1~2 mol%; component A is at least one of ZnO, CaO, B2O3, and Al2O3; component B is at least one of Na2O and K2O; component C is at least one of ZrO2, SnO2, and La2O3; and component D is at least one of BaO, Nb2O5, and Sb2O3; wherein, 2.1 ≤ SiO2 / Li2O ≤ 2.8.

[0010] Preferably, SiO2 is 62 - 71 mol%, Li2O is 21 - 27 mol%, and P2O5 is 1.6 - 3 mol%. Preferably, 2.15 ≤ SiO2 / Li2O ≤ 2.65.

[0011] Furthermore, for component A, ZnO + CaO ≤ 6 mol%, B2O3 + Al2O3 ≤ 6 mol% or 1 mol% ≤ ZnO + CaO + B2O3 + Al2O3 ≤ 8 mol%; for component B, 2 mol% ≤ Na2O + K2O ≤ 6 mol%; for component C, 0 < ZrO2 + SnO2 + La2O3 ≤ 2 mol% or ZrO2 ≤ 0.5 mol%; for component D, 0.3 ≤ BaO + Nb2O5 + Sb2O3 ≤ 2 mol%.

[0012] Preferably, for component A, 1 mol% ≤ ZnO + CaO ≤ 5 mol%, 1 mol% ≤ B2O3 + Al2O3 ≤ 3 mol%, and 2 mol% ≤ ZnO + CaO + B2O3 + Al2O3 ≤ 6 mol%; for component D, 0.5 mol% ≤ BaO + Nb2O5 + Sb2O3 ≤ 1.7 mol%.

[0013] Furthermore, the crystal grains of the glass-ceramics are columnar or acicular in shape.

[0014] Preferably, the average radial size of the crystal grains of the glass-ceramics ≤ 0.3 μm, the average length ≤ 3 μm, and the average aspect ratio is 1 - 15. More preferably, the average radial size of the crystal grains of the glass-ceramics ≤ 0.2 μm, the average length is 0.2 - 1.5 μm, and the average aspect ratio is 4 - 15.

[0015] Furthermore, the flexural strength of the glass-ceramics ≥ 500 MPa, and the fracture toughness ≥ 2.5 MPa·m 1 / 2 .

[0016] Furthermore, the transmittance of the glass-ceramics for light with a wavelength of 550 nm at a thickness of 1 mm ≥ 88%, and the haze at a thickness below 1 mm ≤ 0.4%.

[0017] To optimize the microstructure of transparent glass-ceramics and improve their mechanical properties and light transmittance, it is necessary to control the content of the main components. Specifically, the molar ratio of (B2O3+Al2O3) / (SiO2+Li2O) should be ≤0.07; the molar ratio of (SiO2+Li2O) / (Na2O+K2O) should be in the range of 13~100, preferably in the range of 17~58; the molar ratio of SiO2 / (Nb2O5+Sb2O3+BaO) should be in the range of 20~240, preferably in the range of 35~84; the molar ratio of Li2O / (ZrO2+P2O5) should be in the range of 6~18, preferably in the range of 8~14; and the molar ratio of (SiO2+P2O5) / (Li2O+Na2O+K2O) should be in the range of 1.9~2.8.

[0018] This transparent glass-ceramic possesses unique microstructural features: a large number of high aspect ratio microcrystalline phases coexist with a small amount of residual glass phase. The high aspect ratio grains (exhibiting long columnar or needle-like shapes) interweave and interlock, forming a three-dimensional network structure. When cracks propagate within this structure, various toughening mechanisms are triggered, including grain bridging, grain pull-out, transgranular fracture, intergranular crack deflection, and crack branching. These effects significantly dissipate crack propagation energy, effectively hindering further crack extension, thereby greatly enhancing the strength and fracture toughness of the transparent glass-ceramic. This toughened microstructure and its toughening mechanism are difficult to achieve using spherical equiaxed nanocrystals commonly employed in existing technologies.

[0019] The base glass used in this invention for preparing the above-mentioned self-toughened transparent microcrystalline glass has the same composition as the microcrystalline glass.

[0020] The method for preparing self-toughened transparent microcrystalline glass according to the present invention involves heat-treating the base glass by first heating it from room temperature to a first crystallization heat preservation stage of 600~750 ℃ ​​for one heat preservation, and then heating it to a second crystallization heat preservation stage of 750~870 ℃ for a second heat preservation, thereby obtaining self-toughened transparent microcrystalline glass.

[0021] Furthermore, the heating rate is 1~20 ℃ / min, the first holding time is 0.1~1 hour, and the second holding time is 0.1~5 hours.

[0022] Furthermore, the preparation method of self-toughened transparent glass-ceramics also includes a chemical strengthening step, in which the self-toughened transparent glass-ceramics is placed in molten salt for one or more steps of ion exchange to obtain chemically strengthened self-toughened transparent glass-ceramics.

[0023] Furthermore, the molten salt is at least one of rubidium salt, potassium salt, and sodium salt, and the temperature for one or more steps of ion exchange is 380~520 °C, with a total time of 4~18 hours.

[0024] Furthermore, the multi-step ion exchange is carried out sequentially in the first molten salt and the second molten salt; the first molten salt includes: 0~75 wt% potassium salt, 0~10 wt% rubidium salt, and the remainder is sodium salt; the second molten salt includes: 0~50 wt% sodium salt, 0~100 wt% potassium salt, and the remainder is rubidium salt.

[0025] Preferably, the sodium salt is NaNO3, the potassium salt is KNO3, and the rubidium salt is RbNO3.

[0026] The chemically strengthened self-toughened transparent microcrystalline glass obtained by the above preparation method has a surface compressive stress ≥410 MPa, a compressive stress layer depth of at least 88 μm, a Vickers hardness ≥8 GPa, and a bending strength ≥750 MPa.

[0027] The present invention describes an article made of the aforementioned self-toughened transparent microcrystalline glass, base glass, or chemically strengthened self-toughened transparent microcrystalline glass. The article includes mobile phone display cover plates, camera protective lenses, fingerprint recognition module substrates, smart wearable device screens, home appliance panels, automotive lens protective covers, automotive display screen covers, lidar protective covers, aircraft portholes, deep-sea exploration equipment windows, photovoltaic glass covers, microscope lens covers, nuclear industry observation windows, robot shells, and robot interactive display screens.

[0028] This invention provides an application of the above-mentioned self-toughened transparent microcrystalline glass, base glass, chemically strengthened self-toughened transparent microcrystalline glass, or its products in optical equipment, electronic equipment, display equipment, automobiles, aerospace equipment, marine engineering equipment, new energy equipment, special industrial equipment, robots, or household goods.

[0029] Preparation principle: SiO2 is the basic oxide for constructing the network structure of silicate glass. It forms a three-dimensional network by connecting silicon-oxygen tetrahedra, imparting basic mechanical strength and chemical stability to the glass. In this invention, the molar content of SiO2 is controlled between 58 and 75 mol%, preferably 62 to 71 mol%.

[0030] In this invention, Li₂O plays a dual role: firstly, as a flux, it significantly reduces the high-temperature viscosity of the glass melt and improves melting efficiency; secondly, it provides Li₂O. +Ions participate in the formation of the target crystalline phases (lithium disilicate Li₂Si₂O₅, lithium phosphate Li₃PO₄) and are essential components for phase formation. In this invention, the molar content of Li₂O is 18~30 mol%, preferably 21~27 mol%. If the Li₂O content is lower than 18 mol%, and the SiO₂ / Li₂O ratio is too high, it will lead to the direct formation of Li₂Si₂O₅ (and the grains are usually quite coarse) and the precipitation of other impurity phases such as SiO₂ (e.g., β-cristobalite phase, β-quartz phase, β-quartz solid solution, etc.) during the crystallization process of the matrix glass. The more impurities with different physical properties there are, the more the material scatters light, leading to a significant decrease in the transparency of glass-ceramics when the grain size is larger than the nanometer scale. If the Li₂O content is higher than 30 mol% and the SiO₂ / Li₂O ratio is too low, the resulting glass-ceramic phase will be dominated by lithium metasilicate, or a coexistence of lithium metasilicate and lithium disilicate, resulting in low hardness, poor corrosion resistance, and low strength and toughness. Extensive research conducted by the inventors indicates that the SiO₂ / Li₂O molar ratio should be in the range of 2.1 to 2.8, preferably 2.15 to 2.65. Within the ratio range defined by this invention, lithium metasilicate can preferentially precipitate and completely transform into lithium disilicate during subsequent crystallization, thereby obtaining a long columnar grain microstructure with self-toughening characteristics.

[0031] In this invention, P2O5 is used as the main nucleating agent. It has a strong affinity for Li⁺ in the glass melt, inducing uniform bulk nucleation during heat treatment and providing sufficient nucleation sites for subsequent crystalline phase precipitation. The molar content of P2O5 in this invention is 1.3~3.5 mol%, preferably 1.6~3 mol%. When its content is below 1.3 mol%, the nucleation density is insufficient, the internucleation distance is too large, leading to unrestricted grain growth and coarsening. When the content exceeds 3.5 mol%, an excess of lithium phosphate crystalline phase easily forms in the system, interfering with the precipitation of the main crystalline phase and potentially inducing glass phase separation, thus impairing optical homogeneity.

[0032] TiO2 is commonly used as a nucleating agent in lithium disilicate glass-ceramics in existing technologies. Extensive research by the inventors has revealed that the introduction of TiO2 affects the physical properties of the matrix glass, significantly reducing transparency and easily causing the lithium disilicate grains to become coarser, further reducing light transmittance. To achieve high transparency, this invention excludes the introduction of TiO2.

[0033] MgO is also commonly used as one of the oxide components in lithium disilicate glass-ceramics. Extensive research by the inventors has revealed that the introduction of MgO induces the formation of β-cristobalite and β-quartz solid solution-like impurities, interfering with the transformation pathway from lithium metasilicate to lithium disilicate, and hindering the formation of long columnar grains and the achievement of self-toughening effects. Therefore, this invention excludes the introduction of MgO to achieve high transparency.

[0034] ZnO and CaO, as divalent network modifier oxides, can fill the gaps in the glass network and regulate the melt flow and thermal expansion behavior of the glass. In this invention, the total molar amount of both satisfies ZnO+CaO ≤ 6 mol%, preferably 1 mol% ≤ ZnO+CaO ≤ 5 mol%. Appropriate introduction can improve glass forming properties and chemical durability, but excessive addition will over-modify the network structure and inhibit the preferential precipitation of the target crystalline phase.

[0035] Both B2O3 and Al2O3 can participate in the construction of the glass network, enhancing network connectivity and improving the stability and devitrification resistance of the base glass. In this invention, the total molar amount of both satisfies B2O3 + Al2O3 ≤ 6 mol%, preferably 1 mol% ≤ B2O3 + Al2O3 ≤ 3 mol%. Appropriate amounts help suppress spontaneous crystallization of the base glass during heating, ensuring the controllability of subsequent heat treatment, and can also adjust the refractive index of the glass phase, facilitating optical matching. When their molar content exceeds 3%, it leads to the precipitation of other phases besides lithium disilicate, such as lithium aluminum silicon phases like petalite, which not only hinders the transformation path of lithium metasilicate to lithium disilicate, but the formation of impurity phases also easily leads to a decrease in light transmittance.

[0036] This invention simultaneously limits the total molar amount of ZnO, CaO, B2O3, and Al2O3 to 0.1~8 mol%, preferably, 1 mol% ≤ ZnO+CaO+B2O3+Al2O3 ≤ 8 mol%. Studies have found that when the total amount of these four oxides exceeds 8%, the glass network structure is over-modified, the crystallization path becomes complex, the risk of excessive precipitation of impurities increases significantly, and it is difficult to obtain glass-ceramics with lithium disilicate as the main crystalline phase.

[0037] Na₂O and K₂O, as alkali metal oxides, can effectively reduce the high-temperature viscosity of glass, improve melting efficiency, and provide exchangeable alkali metal ions for subsequent chemical strengthening processes. This invention introduces at least one of Na₂O and K₂O, with a total molar concentration of 1-6 mol%, preferably 2 mol% < Na₂O + K₂O ≤ 6 mol%. If the total concentration is less than 1 mol%, melting is difficult and the ion exchange effect is limited; if it is greater than 6 mol%, the chemical stability of the glass decreases, and the precipitation of lithium disilicate may be inhibited.

[0038] ZrO2, SnO2, and La2O3 are high field strength cationic oxides, which are beneficial for improving the chemical stability and mechanical strength of glass. In this invention, the total molar content of the three is 0-2 mol%, preferably satisfying 0 < ZrO2 + SnO2 + La2O3 ≤ 2 mol%. Appropriate introduction helps improve the uniformity of the microstructure and adjust the refractive index of the glass phase, but excessive addition will affect the formation of long columnar grains. Through extensive research, the inventors have found that, in order to form high aspect ratio grains in the glass-ceramic, the molar content of ZrO2 should not exceed 0.5 mol%.

[0039] In this invention, BaO, Nb₂O₅, and Sb₂O₃ are primarily used as clarifying agents, helping to reduce residual bubbles in the glass melt and improve the optical uniformity of the material. Simultaneously, these components can also adjust the refractive index of the glass phase. In this invention, the total molar amount of both components satisfies the following condition: 0.1 mol% < BaO + Nb₂O₅ + Sb₂O₃ ≤ 2 mol%, preferably 0.3% ≤ BaO + Nb₂O₅ + Sb₂O₃ ≤ 2 mol%, and preferably 0.5 mol% ≤ BaO + Nb₂O₅ + Sb₂O₃ ≤ 2 mol%.

[0040] The present invention also includes a high-hardness transparent microcrystalline glass, wherein the crystal phase of the microcrystalline glass includes lithium disilicate, lithium phosphate, and at least one of lithium feldspar, β-quartz or their solid solutions, lithium metasilicate, β-spodumene or their solid solutions, and has an aspect ratio of 1 to 30. The microcrystalline glass has a transmittance of ≥82% for light with a wavelength of 400 to 800 nm at a thickness of 1 mm, a Vickers hardness of ≥7.7 GPa, and a crystallinity of 50% to 85%.

[0041] Furthermore, the high-hardness transparent microcrystalline glass comprises the following molar percentages of substances: SiO2 63~80 mol%, Li2O 18~30 mol%, P2O5 1.3~3.5 mol%, component A 0.5~8 mol%, component B 0.1~6 mol%, component C 0.1~2 mol%, component D 0.3~2 mol%; component A is at least one of ZnO, CaO, B2O3, and Al2O3; component B is at least one of Na2O and K2O; component C is at least one of ZrO2, SnO2, and La2O3; and component D is at least one of BaO, Nb2O5, and Sb2O3; SiO2 / Li2O ≥2.1.

[0042] Preferably, SiO2 is 63~75 mol%, Li2O is 22~27 mol%, and P2O5 is 1.5~3 mol%. Preferably, SiO2 / Li2O is ≥2.5.

[0043] Furthermore, component B satisfies 1 mol% ≤ Na2O+K2O ≤ 6 mol%, and component D satisfies 0.5 mol% < BaO+Nb2O5+ Sb2O3 ≤ 2 mol%.

[0044] Further, the average radial dimension of the microcrystalline glass grains is ≤ 0.3 μm, the average length is ≤ 3 μm, and the average aspect ratio is 1~30. More preferably, the average radial dimension of the microcrystalline glass grains is ≤ 0.2 μm, the average length is 0.2~1.5 μm, and the average aspect ratio is 4~15.

[0045] Furthermore, the four-point flexural strength of the microcrystalline glass is ≥500 MPa, and its fracture toughness is ≥2.5 MPa·m. 1 / 2 .

[0046] Furthermore, the transmittance of the microcrystalline glass to 550 nm wavelength light is ≥85% at a thickness of 1 mm.

[0047] To further improve the hardness of transparent microcrystalline glass and give it superior scratch and abrasion resistance to meet the application requirements of high-end consumer electronics, aerospace and other fields, it is necessary to control the content of the main components, that is, to control the molar ratio of (SiO2+P2O5) / (Li2O+Na2O+K2O) in the range of 2.3~2.8; and the molar ratio of (Al2O3) / (ZnO+CaO+B2O3+Al2O3) in the range of 0.4~1.

[0048] The method for preparing high-hardness transparent microcrystalline glass according to the present invention involves heat treatment of the base glass:

[0049] Step S1: Preparation of the base glass

[0050] Weigh each raw material component according to the above composition, mix them evenly, and put them into a crucible. Melt at 1300~1450℃ for 3~12 hours. After clarification and homogenization, shape it into a transparent base glass of the desired shape.

[0051] Step S2: Annealing of the base glass

[0052] After annealing at 430~520℃ for 1~5 hours, the glass is slowly cooled to room temperature to obtain transparent base glass with internal stress eliminated.

[0053] Step S3: Heat treatment crystallization

[0054] The base glass obtained in step S2 is then heat-treated to obtain high-hardness transparent glass-ceramics. The heat treatment can be performed using one of the following two methods:

[0055] Option 1 (two-stage heat treatment): First, heat the glass from room temperature to 600-740℃ at a heating rate of 1-20℃ / min for the first crystallization stage, and hold for 0.1-4 hours; then heat the glass to 750-870℃ at a heating rate of 1-20℃ / min for the second crystallization stage, and hold for 0.1-5 hours to obtain high-hardness transparent microcrystalline glass.

[0056] Option 2 (one-stage heat treatment): directly heat from room temperature to a crystallization and holding section of 750-870℃ at a heating rate of 1-20℃ / min, and hold for 0.1-5 hours to obtain high-hardness transparent microcrystalline glass.

[0057] Furthermore, the preparation method of high-hardness transparent glass-ceramics also includes:

[0058] Step S4: Chemical Enhancement Step

[0059] The high-hardness transparent microcrystalline glass obtained in step S3 is placed in molten salt for one or more steps of ion exchange to obtain chemically strengthened high-hardness transparent microcrystalline glass.

[0060] Furthermore, the molten salt is at least one of rubidium salt, potassium salt, and sodium salt, and the temperature for one or more steps of ion exchange is 380~500 °C, with a total time of 4~18 hours.

[0061] Furthermore, the multi-step ion exchange is carried out sequentially in the first molten salt and the second molten salt; the first molten salt includes: 0~75 wt% potassium salt, 0~10 wt% rubidium salt, and the remainder is sodium salt; the second molten salt includes: 0~50 wt% sodium salt, 0~100 wt% potassium salt, and 0~100 wt% rubidium salt.

[0062] Preferably, the sodium salt is NaNO3, the potassium salt is KNO3, and the rubidium salt is RbNO3.

[0063] The chemically strengthened high-hardness transparent microcrystalline glass obtained by the above preparation method has a surface compressive stress ≥410 MPa, a compressive stress layer depth of at least 88 μm, a Vickers hardness ≥9 GPa, and a bending strength ≥750 MPa.

[0064] The present invention describes an article made of the aforementioned high-hardness transparent microcrystalline glass or chemically strengthened high-hardness transparent microcrystalline glass. The article includes mobile phone display cover plates, camera protective lenses, fingerprint recognition module substrates, smart wearable device screens, home appliance panels, automotive lens protective covers, automotive display screen covers, lidar protective covers, aircraft portholes, deep-sea exploration equipment windows, photovoltaic glass covers, microscope lens covers, nuclear industry observation windows, robot shells, and robot interactive displays.

[0065] Preparation principle: (1) Precipitation of high hardness crystalline phase: By optimizing the SiO2 / Li2O ratio and increasing the content of component A, a certain amount of high hardness crystalline phases such as lithite and β-quartz are induced to precipitate, which effectively resists the indentation and scratching effects. (2) Network strengthening of residual glass phase: By increasing the SiO2 / Li2O ratio (≥2.5) and controlling the molar ratio of (SiO2+P2O5) / (Li2O+Na2O+K2O), the proportion of network formations (SiO2, P2O5) in the residual glass phase is higher, the glass network connectivity is enhanced, and the intrinsic hardness of the residual glass phase itself is improved, thereby contributing to the overall hardness of the material.

[0066] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0067] 1. This invention overcomes the limitations of the "nano-equiaxed crystal" design concept, constructing a self-toughening microstructure. To achieve high light transmittance, existing transparent glass-ceramics require strict control of grain size below 100 nm, typically with spherical grains. However, the grain boundary strengthening effect is difficult to achieve. This invention, through precise control of composition and heat treatment processes, successfully prepares transparent glass-ceramics with a high crystallinity (50%~85%) and high aspect ratio (1~30) grain microstructure. This structure achieves self-toughening of the transparent glass-ceramic through the synergistic effect of multiple toughening mechanisms, including grain bridging, pull-out, transgranular fracture, crack deflection, and branching—a feat difficult to achieve with existing nano-equiaxed crystal technology.

[0068] 2. While achieving self-toughening, excellent optical transparency is maintained. This invention achieves uniform nucleation through composition optimization and controls the glass phase composition to make the refractive index of the residual glass phase highly matched with the main crystal phase. At the same time, TiO2 and MgO are explicitly excluded to avoid devitrification. As a result, the transmittance of 550 nm light is ≥88% and the haze is ≤0.4% at a thickness of 1 mm, and the transmittance is still ≥80% at a thickness of 4 mm, achieving a unity of high crystallinity, large grain size and high transparency.

[0069] 3. Synergistic effect of intrinsic structure and chemical strengthening significantly improves mechanical properties. The self-toughening structure of this invention provides an ideal stress response basis for chemical strengthening. After chemical strengthening, the compressive stress layer depth is ≥88 μm, the surface compressive stress reaches 410~500 MPa, the Vickers hardness is ≥8 GPa, the four-point bending strength is ≥750 MPa, and the drop ball test height exceeds 1500 mm in 64 g tests. This synergistic effect of "intrinsic structure toughening + surface chemical strengthening" is unmatched by existing technologies that rely solely on nano-equiaxed crystal design or single chemical strengthening.

[0070] 4. Strong process controllability and broad application prospects. The composition and key ratios of this invention are clearly defined, the heat treatment process has a wide window and good reproducibility, making it suitable for industrial production. The microcrystalline glass produced is a novel inorganic non-metallic material that combines high transparency, high hardness, high strength, high toughness, and excellent chemical strengthening response characteristics. It can be used as a key protective material in the next-generation information technology industry, such as mobile phone cover plates, vehicle central control screens, and robot interactive interfaces. It is also suitable for high-end equipment fields such as aircraft portholes and deep-sea exploration windows, and has extremely high commercial value. Attached Figure Description

[0071] Figure 1 The data are quantitative analysis data of XRD phase full spectrum fitting of the self-toughened transparent microcrystalline glass of Example 1 of the present invention.

[0072] Figure 2 This is a SEM image of the self-toughened transparent microcrystalline glass of Embodiment 1 of the present invention after the grain boundary glass phase was removed by etching.

[0073] Figure 3 The transmittance curves of the 1 mm thick self-toughened transparent microcrystalline glass of Example 1 of the present invention are shown at wavelengths of 300~1000 nm.

[0074] Figure 4 This is an optical photograph of the 4 mm thick self-toughened transparent microcrystalline glass of Embodiment 2 of the present invention.

[0075] Figure 5 The transmittance curves of 1 mm and 4 mm thick self-toughened transparent microcrystalline glass in Example 2 of the present invention are shown at wavelengths of 300~800 nm.

[0076] Figure 6 The transmittance curve of the 1 mm thick transparent microcrystalline glass in Example 14 of the present invention at wavelengths of 300~800 nm is shown.

[0077] Figure 7 The transmittance curves of the 1 mm thick transparent microcrystalline glass of Comparative Example 2 of this invention are shown at wavelengths of 300~1000 nm. Detailed Implementation

[0078] The transparent microcrystalline glass of this invention can be used as a key protective material for mobile phone display covers, vehicle central control displays, smart wearable device screens and robot interactive interfaces, serving human-computer interaction terminal equipment in the new generation of information technology industry, and can also be applied to high-end equipment fields such as aircraft portholes and deep-sea exploration windows.

[0079] Unless otherwise specified, all materials and reagents used in the following embodiments are commercially available. Experimental methods not specifically described in the embodiments are generally performed under standard conditions or as recommended by the manufacturer.

[0080] The performance indicators of the glass compositions, microcrystalline glass and / or microcrystalline glass products of the present invention were tested using the following methods:

[0081] Phase analysis: XRD tests were performed on the glass-ceramic using a D2-Phaser X-ray diffractometer from Bruker GmbH, Germany. The phase analysis of the XRD data was performed using MDI Jade 6.5 software and the PDF2 database.

[0082] Crystallinity: The Rietveld method was used to perform full-spectrum fitting and structural refinement on the high-intensity XRD diffraction patterns acquired at low scan rates to obtain quantitative results including the mass percentage of each crystalline phase and the glass phase. The sum of the percentages of each crystalline phase is the crystallinity of the glass-ceramic.

[0083] Determination of grain morphology:

[0084] The glass-ceramic was immersed in a 3 vol% hydrofluoric acid solution for 40 seconds. After rinsing and drying, gold was sputtered onto the surface of the glass-ceramic. The polished and etched surfaces of the glass-ceramic were observed using a field emission scanning electron microscope (SEM) to obtain SEM images with magnifications ranging from 5,000 to 20,000 times. More than 50 grains were randomly selected from the SEM images, and the grain length (i.e., major axis length) and radial dimension (i.e., minor axis length) of each grain were measured. The aspect ratio of the grain was obtained by calculating the ratio of grain length to radial dimension.

[0085] In this invention, the grain morphology is defined as follows: when the aspect ratio is ≥2, it is considered columnar crystal; when the aspect ratio is ≥10, it is acicular crystal.

[0086] Grain size: determined using scanning electron microscopy: the microcrystalline glass was immersed in a 4 vol% hydrofluoric acid solution for 30 s, rinsed and dried, and then gold was sputtered onto the surface of the microcrystalline glass. The surface was then scanned under a field emission scanning electron microscope (FESEM) to determine the grain size.

[0087] Fracture toughness: The test sample has a height of 4mm × width of 2mm × length of 45mm. A 2mm deep notch is machined in the height direction of the center of the sample using a 0.2mm diamond saw blade. The test is conducted using a microcomputer-controlled electronic universal testing machine CMT5105, based on the three-point bending method of a single-sided notched beam, according to ASTM C1421-09 standard.

[0088] Four-point bending strength: The test sample has dimensions of 45 mm in length × 3 mm in height × 4 mm in width. The test was conducted using a microcomputer-controlled electronic universal testing machine CMT5105, with ASTM C1161-13 as the standard.

[0089] Elastic modulus: The elastic modulus of the self-toughened transparent microcrystalline glass was determined according to GB / T 37788-2019 "Test method for elastic modulus of ultrathin glass";

[0090] Vickers hardness: According to GB / T 37900-2019, the Vickers hardness of the self-toughened transparent microcrystalline glass was determined by the "small load Vickers indentation method for testing the hardness and fracture toughness of ultrathin glass". A load of 3 kgf was applied, and each sample was tested 10 times and the average value was taken.

[0091] Light transmittance (also known as light transmittance): The sample was processed to a thickness of 1 mm and the opposite surfaces were polished in parallel. The average light transmittance at 400–800 nm and the light transmittance at 550 nm were measured using a Hitachi U-4100 spectrophotometer.

[0092] Haze: The haze was measured using a WGT-S haze meter, with a 1 mm thick glass sample, and the test was conducted according to GB / T 2410-2008.

[0093] Surface compressive stress: measured using a Japanese Orihara FSM-6000LEUV glass surface stress meter.

[0094] Depth of compressive stress layer: measured using a glass surface stress meter SLP-2000.

[0095] Drop ball test height and impact strength: The drop ball test height and impact strength of self-toughened transparent microcrystalline glass were tested according to GB / T 39814-2021 "Test Method for Impact Strength of Ultra-thin Glass - Drop Ball Impact Method". Specifically, a 147 mm × 72 mm × 0.55 mm sample was polished on both surfaces and placed on a rubber sheet. A 64g steel ball was dropped from a specified height, and the sample withstood the impact without breaking. Specifically, the test started at a drop ball test height of 1000 mm, and the heights were successively increased to 1050 mm, 1100 mm, 1150 mm, and 1200 mm and above without breakage. For the embodiment with "drop ball test height", the microcrystalline glass product was used as the test object. In the embodiment, the test data was recorded as 1500 mm, indicating that the microcrystalline glass product withstood the impact without breaking even when a steel ball was dropped from a height of 1500 mm.

[0096] The technical solution and implementation method of the self-toughened transparent microcrystalline glass of the present invention will be described below with reference to the embodiments.

[0097] Example 1

[0098] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0099] S1. According to the molar ratio of 64 mol% SiO2, 26.6 mol% Li2O, 2 mol% P2O5, 1.9 mol% CaO, 1.2 mol% Al2O3, 2.5 mol% K2O, 0.3 mol% La2O3, 1 mol% Nb2O5 and 0.5 mol% Sb2O3, the sum of the molar masses of each oxide satisfies 100 mol%. Raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, potassium carbonate, lanthanum oxide, niobium pentoxide and antimony trioxide are prepared, weighed and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, and then clarified at 1400 °C for 4 hours. SiO2 / Li2O=2.41, Al2O3 / (SiO2+Li2O)= 0.013, (SiO2+Li2O) / K2O=36.24, SiO2 / (Nb2O5+ Sb2O3) = 42.67, Li2O / (ZrO2+P2O5)=13.3, (SiO2+P2O5) / (Li2O+K2O)= 2.268.

[0100] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300°C, and then annealed in a muffle furnace at 480°C for 2 hours.

[0101] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750°C at a heating rate of 20°C / min and held for 0.2 hours (first crystallization holding stage). After the holding period, the temperature is increased to 830°C at a heating rate of 10°C / min and held for 2 hours (second crystallization holding stage). After the holding period, the temperature is decreased to 100°C at a rate of 5°C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0102] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 470°C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 470°C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 450°C for ion exchange for 8 hours to complete the second chemical strengthening.

[0103] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. Rietveld full-spectrum fitting and refinement of the XRD pattern were performed, along with quantitative analysis of phase content. The results are as follows: Figure 1As shown in the figure. Analysis reveals that the main crystalline phases of this glass-ceramic are lithium disilicate (72.8 wt%) and lithium phosphate (11.7 wt%), with a crystallinity of 84.5%. From Figure 2 The SEM microstructure images show that the transparent glass-ceramic has a microstructure of interlocking long columnar grains with a grain length of 1~1.5 μm, a radial dimension of 0.1~0.2 μm, and an aspect ratio of 8~13.

[0104] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 98.3 GPa, the Vickers hardness is 7.2 GPa, and the fracture toughness is 4.2 MPa·m. 1 / 2 It has a four-point flexural strength of 720 MPa, and at a thickness of 1 mm, its transmittance at 550 nm wavelength is 91.5%, with a haze of 0.25%. Its transmittance curve in the 300–1000 nm wavelength range is shown below. Figure 3 As shown in the figure. The results indicate that the sample is a self-toughened transparent microcrystalline glass with high transparency.

[0105] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 487 MPa, the stress layer depth was 134 μm, the compressive stress at 30 μm from the surface was 168 MPa, the drop height using a 64 g steel ball reached 2000 mm, the impact strength was 1.256 J, the flexural strength was 863 MPa, and the Vickers hardness was 8.4 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0106] Example 2

[0107] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0108] S1. According to the molar ratio of 64.1 mol% SiO2, 25.2 mol% Li2O, 1.6 mol% P2O5, 2.5 mol% ZnO, 5 mol% K2O, 0.1 mol% ZrO2, and 1.5 mol% Nb2O5, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, zinc carbonate, potassium carbonate, zirconium oxide, and niobium pentoxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350°C for 3 hours, followed by clarification at 1400°C for 4 hours. SiO2 / Li2O=2.54, (SiO2+Li2O) / K2O=17.86, SiO2 / Nb2O5=42.73, Li2O / (P2O5+ZrO2)=14.82, (SiO2+P2O5) / (Li2O+K2O)=2.175.

[0109] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300°C, and then annealed in a muffle furnace at 480°C for 2 hours.

[0110] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 700 °C at a heating rate of 5 °C / min and held for 1 h (first crystallization holding stage). After the holding stage, the temperature is increased to 830 °C at a heating rate of 10 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0111] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 420 °C, it is immersed in a molten salt of 80 wt% KNO3 + 20 wt% RbNO3 at 420 °C for ion exchange for 10 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 400 °C for ion exchange for 6 hours to complete the second chemical strengthening.

[0112] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (65.4 wt%) and lithium phosphate (9.8 wt%), with a crystallinity of 75.2%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 1.2–3 μm, a radial dimension of 0.12–0.3 μm, and an aspect ratio of 10–15.

[0113] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus was 101.8 GPa, the Vickers hardness was 7 GPa, and the fracture toughness was 4.03 MPa·m. 1 / 2 The four-point bending strength is 682 MPa. Figure 4 This is an optical photograph of the 4mm thick self-toughened transparent microcrystalline glass of this embodiment. Figure 5 The transmittance curves of the self-toughened transparent microcrystalline glass with thicknesses of 1 mm and 4 mm in this embodiment are shown in the wavelength range of 300 nm to 800 nm. The transmittance at 550 nm is 90.7% when the thickness is 1 mm, and the transmittance at 550 nm is 81.5% when the thickness is 4 mm, with a haze of 0.22%.

[0114] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 452 MPa, the stress layer depth was 130 μm, the compressive stress at 30 μm from the surface was 164 MPa, the drop height using a 64 g steel ball reached 2000 mm, the impact strength was 1.256 J, the flexural strength was 832 MPa, and the Vickers hardness was 8.1 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0115] Example 3

[0116] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0117] S1. According to the molar ratio of 64.5 mol% SiO2, 24.5 mol% Li2O, 2.4 mol% P2O5, 1 mol% CaO, 1 mol% Al2O3, 3 mol% Na2O, 2 mol% K2O, 0.5 mol% ZrO2, and 1.1 mol% BaO, the sum of the molar masses of each oxide satisfies 100 mol%. Raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, sodium carbonate, potassium carbonate, zirconium oxide, and barium carbonate are prepared, weighed, and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, and then clarified at 1400 °C for 4 hours. SiO2 / Li2O=2.63, Al2O3 / (SiO2+Li2O)=0.011, (SiO2+Li2O) / (Na2O+K2O)=17.8, Si O2 / BaO=58.64, Li2O / (ZrO2+P2O5)=8.167, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.268.

[0118] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0119] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 700 °C at a heating rate of 5 °C / min and held for 0.1 h (first crystallization holding stage). After the holding stage, the temperature is increased to 800 °C at a heating rate of 10 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0120] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 450°C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 450°C for ion exchange for 6 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 430°C for ion exchange for 12 hours to complete the second chemical strengthening.

[0121] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (64.6 wt%) and lithium phosphate (7.6 wt%), with a crystallinity of 72.2%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.4–0.8 μm, a radial dimension of 0.12–0.15 μm, and an aspect ratio of 4–7.

[0122] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 100.3 GPa, the Vickers hardness is 7.1 GPa, and the fracture toughness is 2.8 MPa·m. 1 / 2 It has a four-point bending strength of 580 MPa, and its transmittance at 550 nm wavelength is 92% with a thickness of 1 mm and a haze of 0.18%.

[0123] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 452 MPa, the stress layer depth was 116 μm, the compressive stress at 30 μm from the surface was 153 MPa, the drop height using a 64 g steel ball reached 1650 mm, the impact strength was 1.036 J, the flexural strength was 830 MPa, and the Vickers hardness was 8.3 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0124] Example 4

[0125] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0126] S1. According to the molar ratio of 58 mol% SiO2, 21 mol% Li2O, 3.5 mol% P2O5, 5.5 mol% CaO, 0.5 mol% Al2O3, 1.5 mol% B2O3, 2 mol% Na2O, 4 mol% K2O, 1 mol% SnO2, 1 mol% La2O3, 0.5 mol% Nb2O5, 0.5 mol% Sb2O3, and 1 mol% BaO, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, boron oxide, sodium carbonate, potassium carbonate, tin oxide, lanthanum oxide, niobium pentoxide, and barium carbonate are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350°C for 3 hours, followed by clarification at 1400°C for 4 hours. SiO2 / Li2O=2.76, Al2O3 / (SiO2+Li2O)=0.025, (SiO2+Li2O) / (Na2O+K2O)=13.17, Si O2 / (Nb2O5+Sb2O3+BaO)=29, Li2O / P2O5=6, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.278.

[0127] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 470 °C for 2 hours.

[0128] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 700 °C at a heating rate of 5 °C / min and held for 0.2 h (first crystallization holding stage). After the holding stage, the temperature is increased to 800 °C at a heating rate of 10 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0129] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 520 °C, it is immersed in a molten salt of 50 wt% NaNO3 + 50 wt% KNO3 at 520 °C for ion exchange for 2 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 410 °C for ion exchange for 4 hours to complete the second chemical strengthening.

[0130] XRD and SEM analyses were performed on the microcrystalline glass after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the microcrystalline glass were lithium disilicate (64.7 wt%) and lithium phosphate (4.8 wt%), with a crystallinity of 69.5%. The SEM microstructure showed that the transparent microcrystalline glass possessed a microstructure of interlocking, long columnar grains with a grain length of 0.4–0.8 μm, a radial dimension of 0.13–0.17 μm, and an aspect ratio of 4–6.

[0131] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 97.3 GPa, the Vickers hardness is 7.2 GPa, and the fracture toughness is 2.6 MPa·m. 1 / 2 It has a four-point bending strength of 511 MPa, and its transmittance at 550 nm wavelength is 91% with a thickness of 1 mm and a haze of 0.21%.

[0132] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 456 MPa, the stress layer depth was 88 μm, the compressive stress at 30 μm from the surface was 139 MPa, the drop height using a 64 g steel ball reached 1600 mm, the impact strength was 1.005 J, the flexural strength was 773 MPa, and the Vickers hardness was 8.4 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0133] Example 5

[0134] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0135] S1. According to the molar ratio of 65.3 mol% SiO2, 28.2 mol% Li2O, 1.8 mol% P2O5, 0.2 mol% ZnO, 1.2 mol% Al2O3, 2.5 mol% K2O, 0.3 mol% ZrO2, and 0.5 mol% Sb2O3, the sum of the molar masses of each oxide satisfies 100 mol%. Raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, zinc carbonate, aluminum oxide, potassium carbonate, zirconium oxide, and antimony trioxide are prepared, weighed, and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, and then clarified at 1400 °C for 4 hours. SiO2 / Li2O=2.32, Al2O3 / (SiO2+Li2O)=0.013, (SiO2+Li2O) / (Na2O+K2O)= 37.4, SiO2 / Sb2O3=130.6, Li2O / (ZrO2+P2O5)= 13.43, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.186.

[0136] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0137] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 730 °C at a heating rate of 10 °C / min and held for 0.2 h (first crystallization holding stage). After the holding stage, the temperature is increased to 810 °C at a heating rate of 5 °C / min and held for 2 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0138] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 430 °C, it is immersed in molten salt of 80 wt% KNO3 + 20 wt% RbNO3 at 430 °C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in molten salt of 100 wt% RbNO3 at 410 °C for ion exchange for 4 hours to complete the second chemical strengthening.

[0139] XRD and SEM analyses were performed on the microcrystalline glass after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the microcrystalline glass were lithium disilicate (69.7 wt%) and lithium phosphate (8.1 wt%), with a crystallinity of 77.8%. The SEM microstructure showed that the transparent microcrystalline glass possessed a microstructure of interlocking, long columnar grains with a grain length of 0.8–2 μm, a radial dimension of 0.15–0.25 μm, and an aspect ratio of 5–9.

[0140] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus was 104.3 GPa, the Vickers hardness was 7 GPa, and the fracture toughness was 2.8 MPa·m. 1 / 2 It has a four-point bending strength of 538 MPa, and its transmittance at 550 nm wavelength is 89% with a thickness of 1 mm and a haze of 0.25%.

[0141] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 480 MPa, the stress layer depth was 107 μm, the compressive stress at 30 μm from the surface was 141 MPa, the drop height using a 64 g steel ball reached 1550 mm, the impact strength was 0.973 J, the flexural strength was 788 MPa, and the Vickers hardness was 8 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0142] Example 6

[0143] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0144] S1. According to the molar ratio of 64.6 mol% SiO2, 25.1 mol% Li2O, 2.1 mol% P2O5, 1 mol% CaO, 1.2 mol% B2O3, 4 mol% K2O, 0.2 mol% SnO2, 0.6 mol% La2O3, 0.7 mol% Nb2O5, and 0.5 mol% Sb2O3, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, boron oxide, potassium carbonate, tin oxide, lanthanum oxide, niobium pentoxide, and antimony trioxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.57, B2O3 / (SiO2+Li2O)=0.013, (SiO2+Li2O) / K2O=22.43, SiO2 / (Nb2O5+Sb2O3)=53.83, Li2O / P2O5= 11.95, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.292.

[0145] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0146] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 730 °C at a heating rate of 10 °C / min and held for 0.2 h (first crystallization holding stage). After the holding stage, the temperature is increased to 810 °C at a heating rate of 5 °C / min and held for 4 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0147] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 430 °C, it is immersed in molten salt of 80 wt% KNO3 + 20 wt% RbNO3 at 440 °C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in molten salt of 100 wt% RbNO3 at 410 °C for ion exchange for 4 hours to complete the second chemical strengthening.

[0148] XRD and SEM analyses were performed on the microcrystalline glass after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the microcrystalline glass were lithium disilicate (58.4 wt%) and lithium phosphate (10.2 wt%), with a crystallinity of 68.6%. The SEM microstructure showed that the transparent microcrystalline glass possessed a microstructure of interlocking, long columnar grains with a grain length of 0.5–1.6 μm, a radial dimension of 0.1–0.2 μm, and an aspect ratio of 5–8.

[0149] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 99.3 GPa, the Vickers hardness is 7.3 GPa, and the fracture toughness is 3.1 MPa·m. 1 / 2 The four-point bending strength is 580 MPa. The transmittance at 550 nm wavelength is 92% when the thickness is 1 mm, and 80.8% when the thickness is 4 mm. The haze is 0.2%.

[0150] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 471 MPa, the stress layer depth was 132 μm, the compressive stress at 30 μm from the surface was 152 MPa, the drop height using a 64 g steel ball reached 1700 mm, the impact strength was 1.067 J, the flexural strength was 830 MPa, and the Vickers hardness was 8.5 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0151] Example 7

[0152] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0153] S1. According to the molar ratio of 59.8 mol% SiO2, 26.9 mol% Li2O, 2.1 mol% P2O5, 2 mol% ZnO, 1 mol% Al2O3, 5 mol% B2O3, 1.5 mol% Na2O, 0.2 mol% SnO2, and 1.5 mol% Sb2O3, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, aluminum oxide, boron oxide, sodium carbonate, tin oxide, and antimony trioxide are prepared, weighed, and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, and then clarified at 1400 °C for 4 hours. SiO2 / Li2O=2.22, (Al2O3+B2O3) / (SiO2+Li2O)=0.069, (SiO2+Li2O) / Na2O= 57.8, SiO2 / Sb2O3=39.87, Li2O / P2O5= 12.81, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.18.

[0154] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0155] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750 °C at a heating rate of 5 °C / min and held for 0.25 h (first crystallization holding stage). After the holding stage, the temperature is increased to 830 °C at a heating rate of 5 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a heating rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0156] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 520 °C, immerse it in a molten salt of 50 wt% KNO3 + 50 wt% NaNO3 at 520 °C for ion exchange for 1 hour, and then remove it to complete the first chemical strengthening. After the salt dripping is completed, immerse it in a molten salt of 100 wt% KNO3 at 500 °C for ion exchange for 3 hours to complete the second chemical strengthening.

[0157] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (59.3 wt%) and lithium phosphate (8.9 wt%), with a crystallinity of 68.2%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.7–2 μm, a radial dimension of 0.12–0.2 μm, and an aspect ratio of 6–14.

[0158] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 97 GPa, the Vickers hardness is 7.2 GPa, and the fracture toughness is 3.4 MPa·m. 1 / 2 It has a four-point bending strength of 653 MPa, and its transmittance at 550 nm wavelength is 91.7% and its haze is 0.19% when it is 1 mm thick.

[0159] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 465 MPa, the stress layer depth was 153 μm, the compressive stress at 30 μm from the surface was 136 MPa, the drop height using a 64 g steel ball reached 1650 mm, the impact strength was 1.036 J, the flexural strength was 803 MPa, and the Vickers hardness was 8.7 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0160] Example 8

[0161] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0162] S1. According to the molar ratio of 63.5 mol% SiO2, 30 mol% Li2O, 1.3 mol% P2O5, 0.5 mol% ZnO, 0.3 mol% B2O3, 2 mol% K2O, 0.4 mol% ZrO2, and 2 mol% Sb2O3, the sum of the molar masses of each oxide must satisfy 100 mol%. Raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, zinc carbonate, boron oxide, potassium carbonate, zirconium oxide, and antimony trioxide are prepared, weighed, and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, and then clarified at 1400 °C for 4 hours. SiO2 / Li2O=2.12, (Al2O3+ B2O3) / (SiO2+ Li2O)=0.003, (SiO2+Li2O) / K2O=46.75, SiO2 / Sb2O3=31.75, Li2O / (ZrO2+ P2O5)= 17.65, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.025.

[0163] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0164] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750 °C at a heating rate of 5 °C / min and held for 0.25 h (first crystallization holding stage). After the holding stage, the temperature is increased to 870 °C at a heating rate of 5 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a heating rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0165] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 460 °C, it is immersed in a molten salt of 80 wt% KNO3 + 20 wt% RbNO3 at 460 °C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 430 °C for ion exchange for 4 hours to complete the second chemical strengthening.

[0166] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (54.6 wt%) and lithium phosphate (13.7 wt%), with a crystallinity of 66.7%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.15–1 μm, a radial dimension of 0.12–0.16 μm, and an aspect ratio of 1–6.

[0167] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 102.8 GPa, the Vickers hardness is 7 GPa, and the fracture toughness is 2.7 MPa·m. 1 / 2 It has a four-point bending strength of 512 MPa, and its transmittance at 550 nm wavelength is 90.2% and its haze is 0.32% when it is 1 mm thick.

[0168] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 427 MPa, the stress layer depth was 120 μm, the compressive stress at 30 μm from the surface was 110 MPa, the drop height using a 64 g steel ball reached 1550 mm, the impact strength was 0.973 J, the flexural strength was 762 MPa, and the Vickers hardness was 8.4 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0169] Example 9

[0170] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0171] S1. According to the molar ratio of 60.6 mol% SiO2, 25.5 mol% Li2O, 1.9 mol% P2O5, 2.2 mol% CaO, 0.5 mol% Al2O3, 2 mol% B2O3, 1.5 mol% Na2O, 3 mol% K2O, 1.1 mol% La2O3, and 1.7 mol% Nb2O5, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, boron oxide, sodium carbonate, potassium carbonate, lanthanum oxide, and niobium pentoxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.38, Al2O3 / (SiO2+Li2O)=0.029, (SiO2+Li2O) / (Na2O +K2O) =19.13, SiO2 / Nb2O5=35.65, Li2O / (ZrO2+P2O5)=13.42, (SiO2+P2O5) / (Li2O+Na2O+K2O) =2.083.

[0172] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0173] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750 °C at a heating rate of 20 °C / min and held for 0.5 h (first crystallization holding stage). After the holding stage, the temperature is increased to 830 °C at a heating rate of 10 °C / min and held for 0.5 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0174] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 480 °C, immerse it in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 480 °C for ion exchange for 2 hours, and then remove it to complete the first chemical strengthening. After the salt dripping is completed, immerse it in a molten salt of 100 wt% RbNO3 at 460 °C for ion exchange for 5 hours to complete the second chemical strengthening.

[0175] XRD and SEM analyses were performed on the microcrystalline glass after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the microcrystalline glass were lithium disilicate (70.5 wt%) and lithium phosphate (9.1 wt%), with a crystallinity of 79.6%. The SEM microstructure showed that the transparent microcrystalline glass possessed a microstructure of interlocking, long columnar grains with a grain length of 1.2–3 μm, a radial dimension of 0.15–0.25 μm, and an aspect ratio of 8–12.

[0176] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus was 103.3 GPa, the Vickers hardness was 7.1 GPa, and the fracture toughness was 3.6 MPa·m. 1 / 2 It has a four-point bending strength of 596 MPa, and its transmittance at 550 nm wavelength is 91.2% and its haze is 0.23% when it is 1 mm thick.

[0177] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 474 MPa, the stress layer depth was 125 μm, the compressive stress at 30 μm from the surface was 144 MPa, the drop height using a 64 g steel ball reached 1700 mm, the impact strength was 1.067 J, the flexural strength was 846 MPa, and the Vickers hardness was 8.2 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0178] Example 10

[0179] A method for preparing a self-toughened transparent microcrystalline glass includes the following steps:

[0180] S1. According to the molar ratio of 58 mol% SiO2, 26.6 mol% Li2O, 2 mol% P2O5, 4 mol% CaO, 2 mol% ZnO, 0.2 mol% Al2O3, 1 mol% B2O3, 1.8 mol% Na2O, 1.8 mol% K2O, 1.1 mol% La2O3, 0.5 mol% Nb2O5, and 1 mol% Sb2O3, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, zinc carbonate, aluminum oxide, sodium carbonate, potassium carbonate, lanthanum oxide, niobium pentoxide, and antimony trioxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.18, Al2O3 / (SiO2+Li2O)=0.014, (SiO2+Li2O) / (Na2O+K2O)=23.5, SiO2 / (Nb2O5+Sb2O3)= 38.67, Li2O / P2O5= 13.3, (SiO2+P2O5) / (Li2O+Na2O+K2O) =1.987.

[0181] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0182] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750 °C at a heating rate of 20 °C / min and held for 0.5 h (first crystallization holding stage). After the holding stage, the temperature is increased to 830 °C at a heating rate of 10 °C / min and held for 1 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain self-toughened transparent microcrystalline glass.

[0183] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 470 °C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 470 °C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 450 °C for ion exchange for 8 hours to complete the second chemical strengthening.

[0184] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (62.1 wt%) and lithium phosphate (7.2 wt%), with a crystallinity of 69.3%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 1–3 μm, a radial dimension of 0.1–0.2 μm, and an aspect ratio of 8–30.

[0185] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 100.7 GPa, the Vickers hardness is 7 GPa, and the fracture toughness is 3.3 MPa·m. 1 / 2 It has a four-point bending strength of 569 MPa, and its transmittance at 550 nm wavelength is 92% with a thickness of 1 mm and a haze of 0.21%.

[0186] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 462 MPa, the stress layer depth was 114 μm, the compressive stress at 30 μm from the surface was 161 MPa, the drop height using a 64 g steel ball reached 1600 mm, the impact strength was 1.005 J, the flexural strength was 819 MPa, and the Vickers hardness was 8.2 GPa. These results indicate that the self-toughened transparent glass-ceramic was further chemically strengthened.

[0187] The technical solution and implementation method of the high-hardness transparent microcrystalline glass of the present invention will be further illustrated below with more embodiments.

[0188] Example 11

[0189] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0190] S1. According to the molar ratio of 64.5 mol% SiO2, 24.5 mol% Li2O, 3 mol% P2O5, 0.2 mol% ZnO, 3.5 mol% Al2O3, 1.3 mol% Na2O, 1.3 mol% K2O, 0.9 mol% SnO2, and 0.8 mol% BaO, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, diammonium hydrogen phosphate, zinc carbonate, aluminum oxide, sodium carbonate, potassium carbonate, tin oxide, and barium carbonate are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.63, Al2O3 / (SiO2+Li2O)=0.039, (SiO2+Li2O) / (Na2O+K2O)=34.23, SiO2 / BaO=80.63, Li2O / P2O5= 8.167, (SiO2+P2O5) / (Li2O+ Na2O+K2O)=2.491.

[0191] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300°C, and then annealed in a muffle furnace at 480°C for 2 hours.

[0192] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 650 °C at a heating rate of 1 °C / min and held for 0.1 h (first crystallization holding stage). After the holding stage, the temperature is increased to 750 °C at a heating rate of 2 °C / min and held for 3 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0193] S4. After preheating the obtained high-hardness transparent microcrystalline glass to 450 °C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 450 °C for ion exchange for 6 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 430 °C for ion exchange for 12 hours to complete the second chemical strengthening.

[0194] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (52.7 wt%), β-spodumene (13.2 wt%), and lithium phosphate (12.5 wt%), with a crystallinity of 78.4%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.4–1.2 μm, a radial dimension of 0.2–0.18 μm, and an aspect ratio of 4–8.

[0195] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 98 GPa, the Vickers hardness is 8.1 GPa, and the fracture toughness is 3.85 MPa·m. 1 / 2 It has a four-point bending strength of 638 MPa, a light transmittance of 92% at 550 nm wavelength when it is 1 mm thick, and a haze of 0.15%.

[0196] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 435 MPa, the stress layer depth was 129 μm, the compressive stress at 30 μm from the surface was 132 MPa, the drop height using a 64 g steel ball reached 1500 mm, the impact strength was 0.942 J, the flexural strength was 761 MPa, and the Vickers hardness was 9.6 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0197] Example 12

[0198] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0199] S1. According to the molar ratio of 64.5 mol% SiO2, 24.5 mol% Li2O, 2.5 mol% P2O5, 0.5 mol% ZnO, 2.5 mol% Al2O3, 3 mol% Na2O, 1 mol% SnO2, and 1.5 mol% BaO, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, zinc carbonate, aluminum oxide, sodium carbonate, tin oxide, and barium carbonate are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.63, Al2O3 / (SiO2+Li2O) =0.028, (SiO2+Li2O) / Na2O=29.67, SiO2 / BaO=43, Li2O / P2O5=9.8, (SiO2+P2O5) / (Li2O+Na2O) =2.436.

[0200] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 460 °C for 2 hours.

[0201] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 650 °C at a heating rate of 1 °C / min and held for 0.2 h (first crystallization holding stage). After the holding stage, the temperature is increased to 750 °C at a heating rate of 2 °C / min and held for 5 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0202] S4. After preheating the obtained high-hardness transparent microcrystalline glass to 500 °C, immerse it in a molten salt of 50 wt% KNO3 + 50 wt% NaNO3 at 500 °C for ion exchange for 3 hours, and then remove it to complete the first chemical strengthening. After the salt dripping is completed, immerse it in a molten salt of 100 wt% KNO3 at 480 °C for ion exchange for 6 hours to complete the second chemical strengthening.

[0203] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (52.1 wt%), β-lithium feldspar (7 wt%), and lithium phosphate (7.6 wt%), with a crystallinity of 66.7%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 1–2.4 μm, a radial dimension of 0.08–0.25 μm, and an aspect ratio of 6–10.

[0204] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 99.2 GPa, the Vickers hardness is 7.9 GPa, and the fracture toughness is 2.66 MPa·m. 1 / 2 It has a four-point bending strength of 593 MPa, and its transmittance at 550 nm wavelength is 91.5% and its haze is 0.17% when it is 1 mm thick.

[0205] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 463 MPa, the stress layer depth was 112 μm, the compressive stress at 30 μm from the surface was 135 MPa, the drop height using a 64 g steel ball reached 1650 mm, the impact strength was 1.036 J, the flexural strength was 773 MPa, and the Vickers hardness was 9.2 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0206] Example 13

[0207] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0208] S1. According to the molar ratio of 63 mol% SiO2, 22.9 mol% Li2O, 2.6 mol% P2O5, 3 mol% ZnO, 2 mol% Al2O3, 3 mol% Na2O, 1 mol% K2O, 2 mol% SnO2, and 0.5 mol% Nb2O5, the sum of the molar masses of each oxide satisfies 100 mol%. Raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, zinc carbonate, aluminum oxide, sodium carbonate, potassium carbonate, tin oxide, and niobium pentoxide are prepared, weighed, and mixed evenly. The mixture is placed in a platinum crucible and melted in a high-temperature furnace at 1350°C for 3 hours, and then clarified at 1400°C for 4 hours. SiO2 / Li2O=2.75, Al2O3 / (SiO2+Li2O) =0.023, (SiO2+Li2O) / (Na2O+K2O) =21.48, SiO2 / (Nb2O5+Sb2O3+BaO) =126, Li2O / P2O5=8.808, (SiO2+P2O5) / (Li2O+Na2O+K2O) =2.439.

[0209] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300°C, and then annealed in a muffle furnace at 480°C for 2 hours.

[0210] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 700 °C at a heating rate of 5 °C / min and held for 0.5 h (first crystallization holding stage). After the holding period, the temperature is increased to 800 °C at a heating rate of 10 °C / min and held for 1 h (second crystallization holding stage). After the holding period, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0211] S4. After preheating the obtained high-hardness transparent microcrystalline glass to 450 °C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 450 °C for ion exchange for 6 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 430 °C for ion exchange for 12 hours to complete the second chemical strengthening.

[0212] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (51.3 wt%), β-spodumene (10.5 wt%), and lithium phosphate (11.5 wt%), with a crystallinity of 73.3%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.5–0.9 μm, a radial dimension of 0.12–0.17 μm, and an aspect ratio of 4–7.

[0213] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus was 102.1 GPa, the Vickers hardness was 7.8 GPa, and the fracture toughness was 2.9 MPa·m. 1 / 2 It has a four-point bending strength of 564 MPa, and its transmittance at 550 nm wavelength is 91.2% and its haze is 0.2% when it is 1 mm thick.

[0214] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 425 MPa, the stress layer depth was 127 μm, the compressive stress at 30 μm from the surface was 125 MPa, the drop height using a 64 g steel ball reached 1800 mm, the impact strength was 1.13 J, the flexural strength was 814 MPa, and the Vickers hardness was 9.1 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0215] Example 14

[0216] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0217] S1. According to the molar ratio of 66.1 mol% SiO2, 26.4 mol% Li2O, 1.8 mol% P2O5, 0.3 mol% CaO, 1.7 mol% Al2O3, 1.7 mol% Na2O, 1 mol% K2O, 0.2 mol% La2O3, and 0.8 mol% Nb2O5, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, sodium carbonate, potassium carbonate, lanthanum oxide, and niobium pentoxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.5, Al2O3 / (SiO2+Li2O)=0.018, (SiO2+Li2O) / (Na2O+K2O)=34.63, SiO2 / Nb2O5= 82.63, Li2O / P2O5=14.67, (SiO2+P2O5) / (Li2O+Na2O+K2O)=2.333.

[0218] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 4 hours.

[0219] S3. The annealed substrate glass is placed in a high-temperature furnace for crystallization heat treatment. In this embodiment, the first crystallization heat treatment section is not set. The temperature is directly raised from room temperature to 780 °C at a heating rate of 10 °C / min and held for 2 hours (second crystallization heat treatment section). After the heat treatment is completed, the temperature is lowered to 100 °C at a rate of 5 °C / min and the program is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0220] S4. After preheating the prepared self-toughened transparent microcrystalline glass to 450 °C, it is immersed in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 450 °C for ion exchange for 6 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in a molten salt of 100 wt% RbNO3 at 430 °C for ion exchange for 12 hours to complete the second chemical strengthening.

[0221] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (53.1 wt%), β-quartz (13.1 wt%), and lithium phosphate (7.4-13.7 wt%), with a crystallinity of 73.6%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.5–1.5 μm, a radial dimension of 0.13–0.18 μm, and an aspect ratio of 4–9.

[0222] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 99.6 GPa, the Vickers hardness is 7.7 GPa, and the fracture toughness is 3 MPa·m. 1 / 2 Four-point flexural strength 573 MPa, such as Figure 7 At a thickness of 1 mm, its transmittance at a wavelength of 550 nm is 91%, and its haze is 0.23%.

[0223] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 468 MPa, the stress layer depth was 137 μm, the compressive stress at 30 μm from the surface was 148 MPa, the drop height using a 64 g steel ball reached 1850 mm, the impact strength was 1.162 J, the flexural strength was 823 MPa, and the Vickers hardness was 9 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0224] Example 15

[0225] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0226] S1. According to the molar ratio of 70.1 mol% SiO2, 25.5 mol% Li2O, 1.5 mol% P2O5, 0.2 mol% CaO, 1.2 mol% Al2O3, 1 mol% K2O, 0.2 mol% SnO2, 0.1 mol% Nb2O5, and 0.2 mol% BaO, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, potassium carbonate, tin oxide, niobium pentoxide, and barium carbonate are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.75, Al2O3 / (SiO2+Li2O)=0.013, (SiO2+Li2O) / K2O=95.6, SiO2 / (Nb2O5+BaO) =233.7, Li2O / (ZrO2+P2O5)=17, (SiO2+P2O5) / (Li2O+Na2O+K2O) =2.702.

[0227] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 480 °C for 2 hours.

[0228] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 750 °C at a heating rate of 5 °C / min and held for 0.25 h (first crystallization holding stage). After the holding stage, the temperature is increased to 850 °C at a heating rate of 5 °C / min and held for 2 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a heating rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0229] S4. After preheating the obtained high-hardness transparent microcrystalline glass to 460 °C, it is immersed in molten salt of 80 wt% KNO3 + 20 wt% RbNO3 at 460 °C for ion exchange for 4 hours and then removed to complete the first chemical strengthening. After the salt dripping is completed, it is immersed in molten salt of 100 wt% RbNO3 at 430 °C for ion exchange for 4 hours to complete the second chemical strengthening.

[0230] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (51 wt%), β-quartz solid solution (4.3 wt%), and lithium phosphate (2.5 wt%), with a crystallinity of 57.8%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.12–0.6 μm, a radial dimension of 0.1–0.12 μm, and an aspect ratio of 1–5.

[0231] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 100.8 GPa, the Vickers hardness is 7.7 GPa, and the fracture toughness is 2.54 MPa·m. 1 / 2 It has a four-point bending strength of 502 MPa, and its transmittance at 550 nm wavelength is 89.3% and its haze is 0.4% when it is 1 mm thick.

[0232] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 410 MPa, the stress layer depth was 108 μm, the compressive stress at 30 μm from the surface was 118 MPa, the drop height using a 64 g steel ball reached 1500 mm, the impact strength was 0.942 J, the flexural strength was 750 MPa, and the Vickers hardness was 9 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0233] Example 16

[0234] A method for preparing high-hardness transparent microcrystalline glass includes the following steps:

[0235] S1. According to the molar ratio of 65.9 mol% SiO2, 25.2 mol% Li2O, 1.9 mol% P2O5, 0.2 mol% CaO, 2.3 mol% Al2O3, 1 mol% Na2O, 2 mol% K2O, 0.2 mol% SnO2, 0.3 mol% La2O3, and 1 mol% Nb2O5, with the sum of the molar masses of each oxide satisfying 100 mol%, raw materials such as silicon oxide, lithium carbonate, ammonium dihydrogen phosphate, calcium carbonate, aluminum oxide, sodium carbonate, potassium carbonate, tin oxide, lanthanum oxide, and niobium pentoxide are prepared, weighed, and mixed evenly. The mixture is then placed in a platinum crucible and melted in a high-temperature furnace at 1350 °C for 3 hours, followed by clarification at 1400 °C for 4 hours. SiO2 / Li2O=2.62, Al2O3 / (SiO2+Li2O)=0.025, (SiO2+Li2O) / (Na2O +K2O)=30.37, SiO2 / (Nb2O5+Sb2O3+BaO)=65.9, Li2O / (ZrO2+P2O5)=13.26, (SiO2+ P2O5) / (Li2O +Na2O +K2O)=2.404.

[0236] S2. Glass substrates with thicknesses of 1 mm and 4 mm are obtained by cooling and molding in a mold preheated to 300 °C, and then annealed in a muffle furnace at 470 °C for 1 hour.

[0237] S3. The annealed matrix glass is placed in a high-temperature furnace for crystallization heat treatment. The temperature is increased from room temperature to 720 °C at a heating rate of 20 °C / min and held for 0.5 h (first crystallization holding stage). After the holding stage, the temperature is increased to 830 °C at a heating rate of 10 °C / min and held for 0.2 h (second crystallization holding stage). After the holding stage, the temperature is decreased to 100 °C at a rate of 5 °C / min and the process is stopped. The glass is then cooled with the furnace to obtain high-hardness transparent microcrystalline glass.

[0238] S4. After preheating the obtained high-hardness transparent microcrystalline glass to 480°C, immerse it in a molten salt of 50 wt% KNO3 + 50 wt% RbNO3 at 480°C for ion exchange for 2 hours, and then remove it to complete the first chemical strengthening. After the salt dripping is completed, immerse it in a molten salt of 100 wt% RbNO3 at 460°C for ion exchange for 5 hours to complete the second chemical strengthening.

[0239] XRD and SEM analyses were performed on the glass-ceramic after the crystallization heat treatment in step S3. The analysis revealed that the main crystalline phases of the glass-ceramic were lithium disilicate (56.8 wt%), β-quartz (7.3 wt%), and lithium phosphate (10.2 wt%), with a crystallinity of 74.3%. The SEM microstructure showed that the transparent glass-ceramic possessed a microstructure of interlocking, long columnar grains with a grain length of 0.8–2.3 μm, a radial dimension of 0.13–0.22 μm, and an aspect ratio of 6–10.

[0240] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 99.5 GPa, the Vickers hardness is 7.8 GPa, and the fracture toughness is 3.2 MPa·m. 1 / 2 It has a four-point bending strength of 557 MPa, and its transmittance at 550 nm wavelength is 91.5% and its haze is 0.22% when it is 1 mm thick.

[0241] The transparent glass-ceramic obtained in step S4 was subjected to performance testing, and the results are as follows: the surface compressive stress was 492 MPa, the stress layer depth was 135 μm, the compressive stress at 30 μm from the surface was 127 MPa, the drop height using a 64 g steel ball reached 1900 mm, the impact strength was 1.193 J, the flexural strength was 807 MPa, and the Vickers hardness was 9.3 GPa. These results indicate that the transparent glass-ceramic underwent further chemical strengthening.

[0242] Comparative Example 1

[0243] The remaining steps of this comparative example are the same as those in Example 1, except that the glass composition also includes 0.4 mol% TiO2 to replace part of the P2O5, with the P2O5 content being 1.6 mol%. The same performance tests as in Example 1 were performed, and the results showed that the main crystalline phases of the microcrystalline glass sample obtained in step S3 were lithium disilicate (58.8 wt%), lithium phosphate (10.2 wt%), and quartz (12.5 wt%), with a crystallinity of 81.5%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 1–2.6 μm, a radial dimension of 0.32–0.45 μm, and an aspect ratio of 3–6 for the columnar grains.

[0244] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 99.1 GPa, the Vickers hardness is 6.8 GPa, and the fracture toughness is 2.1 MPa·m. 1 / 2 The four-point bending strength is 435 MPa, and the transmittance at 550 nm wavelength is 35.4% when the thickness is 1 mm.

[0245] This comparative example shows that the introduction of TiO2 leads to grain coarsening, severely impairing transparency and mechanical properties, and also induces the precipitation of impurity phases such as quartz. Example 1, by using P2O5 as the main nucleating agent, achieved the precipitation of a single silicon-containing crystalline phase of lithium disilicate and slender columnar grains, achieving significant advantages in both light transmittance and fracture toughness.

[0246] Comparative Example 2

[0247] The remaining steps of this comparative example are the same as those in Example 2, except that the glass composition contains 0.9 mol% ZrO2, and the contents of the other components are reduced proportionally. The same performance tests as in Example 2 were performed, and the results showed that the main crystalline phases of the microcrystalline glass sample obtained in step S3 were lithium disilicate (59.5 wt%) and lithium phosphate (14.2 wt%), with a crystallinity of 73.7%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 0.4–1.6 μm, a radial dimension of 0.3–0.6 μm, and an aspect ratio of 1–3 for the columnar grains.

[0248] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 100.8 GPa, the Vickers hardness is 7.1 GPa, and the fracture toughness is 2.03 MPa·m. 1 / 2 Four-point flexural strength 422 MPa, such as Figure 6 At a thickness of 1 mm, its transmittance at a wavelength of 550 nm is 29.5%.

[0249] This comparative example shows that excessive addition of high field strength cationic oxide ZrO2 hinders Li⁺ migration, leading to grain coarsening and a decrease in aspect ratio. Therefore, extensive research has shown that the ZrO2 content should be controlled at ≤0.5 mol%. Example 2 obtained columnar grains with an aspect ratio of 10-15 at a low ZrO2 content, achieving excellent toughening effect.

[0250] Comparative Example 3

[0251] The remaining steps of this comparative example are the same as those in Example 2, except that the glass composition is 64.89 mol% SiO2, 25.58 mol% Li2O, 1.63 mol% P2O5, 3 mol% CaO, 4 mol% Na2O, and 0.9 mol% ZrO2. The same performance tests as in Example 2 were performed, and the results showed that the main crystalline phases of the microcrystalline glass sample obtained in step S3 were lithium disilicate (53.2 wt%), lithium phosphate (8.8 wt%), and cristobalite (13.5 wt%), with a crystallinity of 75.5%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 0.8–1.6 μm, a radial dimension of 0.5–0.8 μm, and an aspect ratio of 1–2 for the columnar grains.

[0252] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 101.5 GPa, the Vickers hardness is 6.9 GPa, and the fracture toughness is 2.23 MPa·m. 1 / 2 It has a four-point bending strength of 382 MPa and a light transmittance of 10.2% at a wavelength of 550 nm when it is 1 mm thick.

[0253] Comparative Example 3 lacks network-regulating components such as B2O3 and Al2O3. Besides lithium disilicate and lithium phosphate, it also forms a cristobalite phase (1.484~1.487) with a lower refractive index than lithium disilicate, and the grains are coarse. Furthermore, Comparative Example 3 lacks high-field-strength oxide components such as Nb2O5, Sb2O3, and BaO, resulting in a higher light scattering coefficient and extremely low transparency in the glass-ceramic. Example 2 demonstrates that the appropriate addition of components A and D is crucial for controlling the crystal phase composition and obtaining high aspect ratio grains and high transparency.

[0254] Comparative Example 4

[0255] The remaining steps of this comparative example are the same as those in Example 13, except that the glass composition contains more K2O (4 mol%), and the contents of other components are proportionally reduced, with K2O+Na2O at 6.8 mol%. The same performance tests as in Example 13 were performed, and the results showed that the main crystalline phases of the high-hardness microcrystalline glass sample obtained in step S3 were lithium disilicate (42.2 wt%), lithium phosphate (9.8 wt%), and lithium metasilicate (11.5 wt%), with a crystallinity of 63.5%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 0.5–0.9 μm, a radial dimension of 0.4–0.7 μm, and an aspect ratio of 1–2 for the columnar grains.

[0256] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 94.9 GPa, the Vickers hardness is 7.3 GPa, and the fracture toughness is 1.7 MPa·m. 1 / 2 It has a four-point bending strength of 347 MPa and a light transmittance of 24.8% at 550 nm wavelength when it is 1 mm thick.

[0257] In Comparative Example 4, the excessively high Na₂O and K₂O content (>6 mol%) inhibited the precipitation of lithium disilicate, resulting in residual lithium metasilicate and coarsening of the grains. Example 13, by optimizing the alkali metal content, obtained a high-purity lithium disilicate crystal phase and excellent overall performance.

[0258] Comparative Example 5

[0259] The remaining steps of this comparative example are the same as those in Example 7, except that the glass composition contains more Al2O3 (7 mol%), and the contents of the other components are reduced proportionally. The same performance tests as in Example 7 were performed, and the results showed that the main crystalline phases of the microcrystalline glass sample obtained in step S3 were lithium disilicate (33.7 wt%), β-spodumene (25.5 wt%), lithium phosphate (8.3 wt%), and lithium metasilicate (6.7 wt%), with a crystallinity of 74.2%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 0.1–0.3 μm, a radial dimension of 0.05–0.1 μm, and an aspect ratio of 1–3 for the columnar grains.

[0260] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 102 GPa, the Vickers hardness is 7.1 GPa, and the fracture toughness is 1.9 MPa·m. 1 / 2 It has a four-point bending strength of 416 MPa and a light transmittance of 26.8% at a wavelength of 550 nm when it is 1 mm thick.

[0261] In Comparative Example 5, excessive addition of Al2O3 led to the precipitation of impurity phases such as lepidolite and β-spodumene, hindering the transformation pathway from lithium metasilicate to lithium disilicate. Example 7, with optimized Al2O3 content, achieved a single silicon-containing crystalline phase of lithium disilicate and excellent toughening effect.

[0262] Comparative Example 6

[0263] The remaining steps of this comparative example are the same as those in Example 2, except that the glass composition contains 65.53 mol% SiO2, 27.36 mol% Li2O, 1.26 mol% P2O5, 1.84 mol% Al2O3, 2.26 mol% K2O, and 1.75 mol% Nb2O5. The same performance tests as in Example 2 were performed, and the results showed that the main crystalline phases of the microcrystalline glass sample obtained in step S3 were lithium disilicate (54.3 wt%), lithium phosphate (10.2 wt%), and lithium niobate (8.5 wt%), with a crystallinity of 73%. SEM micrographs show that the transparent microcrystalline glass has a grain length of 0.15–1.5 μm, a radial dimension of 0.1–0.2 μm, and an aspect ratio of 1–10 for the columnar grains.

[0264] The transparent glass-ceramic sample obtained in step S3 was subjected to performance tests, and the results are as follows: the average Young's modulus is 101.5 GPa, the Vickers hardness is 7.3 GPa, and the fracture toughness is 2.4 MPa·m. 1 / 2 The four-point bending strength is 446MPa. The appearance of the sample is similar to that of lime, white and opaque. The transmittance at 550 nm wavelength is 0% when it is 1mm thick.

[0265] In Comparative Example 6, the amount of P2O5 added was insufficient (1.26 mol%), which resulted in the formation of a high-refractive-index LiNbO3 phase (refractive index of about 2.2) in addition to lithium disilicate and lithium phosphate. This caused severe light scattering, and the microcrystalline glass was completely opaque when it was 1 mm thick.

Claims

1. A high-hardness transparent microcrystalline glass, characterized in that: The crystal phase of the microcrystalline glass includes lithium disilicate, lithium phosphate, and at least one of lithium feldspar, β-quartz or their solid solutions, lithium metasilicate, β-spodumene or their solid solutions. It has an aspect ratio of 1 to 30, and the microcrystalline glass has a transmittance of ≥82% for light with a wavelength of 400 to 800 nm at a thickness of 1 mm, a Vickers hardness of ≥7.7 GPa, and a crystallinity of 50% to 85%.

2. The high-hardness transparent microcrystalline glass according to claim 1, characterized in that: The high-hardness transparent microcrystalline glass comprises the following molar percentages of substances: SiO2 63~80 mol%, Li2O 18~30 mol%, P2O5 1.3~3.5 mol%, component A 0.5~8 mol%, component B 0.1~6 mol%, component C 0.1~2 mol%, component D 0.3~2 mol%; wherein component A is at least one of ZnO, CaO, B2O3, and Al2O3, component B is at least one of Na2O and K2O, component C is at least one of ZrO2, SnO2, and La2O3, and component D is at least one of BaO, Nb2O5, and Sb2O3; and SiO2 / Li2O ≥2.

1.

3. The high-hardness transparent microcrystalline glass according to claim 2, characterized in that: The B component satisfies 1 mol% ≤ Na2O+K2O ≤ 6 mol%, and the D component satisfies 0.5 mol% < BaO+Nb2O5+ Sb2O3 ≤ 2 mol%.

4. The high-hardness transparent microcrystalline glass according to claim 1, characterized in that: The average radial dimension of the microcrystalline glass grains is ≤ 0.3 μm, the average length is ≤ 3 μm, and the average aspect ratio is 1~30.

5. The high-hardness transparent microcrystalline glass according to claim 1, characterized in that: The microcrystalline glass has a four-point bending strength ≥ 500 MPa and a fracture toughness ≥ 2.5 MPa·m. 1 / 2 .

6. The high-hardness transparent microcrystalline glass according to claim 1, characterized in that: The microcrystalline glass has a transmittance of ≥85% for 550 nm wavelength light at a thickness of 1 mm.

7. The high-hardness transparent microcrystalline glass according to claim 2, characterized in that: The molar ratio of (SiO2+P2O5) / (Li2O+Na2O+K2O) is in the range of 2.3~2.8; the molar ratio of (Al2O3) / (ZnO+CaO+B2O3+Al2O3) is in the range of 0.4~1.

8. A method for preparing a high-hardness transparent microcrystalline glass according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1: Preparation of the base glass Weigh each raw material component according to the above composition, mix them evenly, and put them into a crucible. Melt at 1300~1450℃ for 3~12 hours. After clarification and homogenization, shape it into a transparent base glass of the desired shape. Step S2: Annealing of the base glass After annealing at 430~520℃ for 1~5 hours, the glass is slowly cooled to room temperature to obtain transparent base glass with internal stress eliminated.

9. Step S3: Heat treatment crystallization The base glass obtained in step S2 is heat-treated to obtain high-hardness transparent microcrystalline glass.

10. The method for preparing a high-hardness transparent microcrystalline glass according to claim 8, characterized in that: In step S3, the heat treatment first raises the temperature from room temperature to the first crystallization holding stage at a heating rate of 1~20 ℃ / min to 600~740 ℃, and holds for 0.1~4 hours; then raises the temperature to the second crystallization holding stage at a heating rate of 1~20 ℃ / min to 750~870 ℃, and holds for 0.1~5 hours, to obtain high-hardness transparent microcrystalline glass.

11. The method for preparing a high-hardness transparent microcrystalline glass according to claim 8, characterized in that: In step S3, the heat treatment directly raises the temperature from room temperature to a crystallization holding section of 750-870 ℃ at a heating rate of 1-20 ℃ / min, and holds for 0.1-5 hours to obtain high-hardness transparent microcrystalline glass.

12. The method for preparing a high-hardness transparent microcrystalline glass according to claim 8, characterized in that: Also includes: Step S4: Chemical Enhancement Step The high-hardness transparent microcrystalline glass obtained in step S3 is placed in molten salt for one or more steps of ion exchange to obtain chemically strengthened high-hardness transparent microcrystalline glass.

13. The method for preparing a high-hardness transparent microcrystalline glass according to claim 11, characterized in that: The molten salt is at least one of rubidium salt, potassium salt, and sodium salt, and the temperature of the one-step or multi-step ion exchange is 380~500 ℃, and the total time is 4~18 hours.

14. The method for preparing a high-hardness transparent microcrystalline glass according to claim 11, characterized in that: The multi-step ion exchange is carried out sequentially in the first molten salt and the second molten salt; The first molten salt comprises: 0-75 wt% potassium salt, 0-10 wt% rubidium salt, and the remainder being sodium salt; the second molten salt comprises: 0-50 wt% sodium salt, 0-100 wt% potassium salt, and 0-100 wt% rubidium salt.

15. The chemically strengthened high-hardness transparent microcrystalline glass obtained by the preparation method of high-hardness transparent microcrystalline glass according to claim 11, characterized in that: Surface compressive stress ≥410 MPa, compressive stress layer depth at least 88 μm, Vickers hardness ≥9 GPa, flexural strength ≥750 MPa.

16. An article, characterized in that: Made from the high-hardness transparent microcrystalline glass of claim 8 or the chemically strengthened high-hardness transparent microcrystalline glass of claim 11, the products include mobile phone display covers, camera protective lenses, fingerprint recognition module substrates, smart wearable device screens, home appliance panels, automotive lens protective covers, automotive display screen covers, lidar protective covers, aircraft portholes, deep-sea exploration equipment windows, photovoltaic glass covers, microscope lens covers, nuclear industry observation windows, robot shells, and robot interactive displays.

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