High-strength transparent microcrystalline glass based on cluster component unit design and preparation method thereof

Abstract

A high-strength transparent glass-ceramic based on cluster component unit design and its preparation method belong to the field of glass-ceramic technology. The mass percentages of its components are: 0.8~2.5wt% Li₂O, 1.6~5.3wt% Na₂O, 9.3~25.9wt% ZnO, 0.1~14.3 wt% MgO, 23.3~32.4wt% Al₂O₃, 31.8~48.0wt% SiO₂, 3.3~7.0wt% ZrO₂, and 2.1~4.5wt% TiO₂. Furthermore, it satisfies the following synergistic relationships: 1.2≤Li₂O +0.32Na₂O≤4.3 wt%; 47.9≤ZnO + 2.2MgO + 1.6Al₂O₃≤65.8wt%; 17.9≤SiO₂ + 0.59ZrO₂ + 0.75TiO₂≤59.8wt%. This invention, based on a cluster-connecting atom model, designs a novel glass-ceramic through the synergistic combination of multivalent unit cells. By introducing ZnO and MgO into the LAS matrix, high-modulus (Mg,Zn)Al₂O₄ spinel and LiAlSi₂O₆ spodumene phases are precipitated, improving the mechanical properties of the glass-ceramic. The grains are uniformly distributed without significant agglomeration, maintaining the optical transparency of the glass-ceramic. The high-strength transparent glass-ceramic prepared by this invention possesses both excellent comprehensive mechanical properties and high light transmittance, meeting the visible light transmittance requirements of GB / T 45822-2025 for glass-ceramics, and can be considered a preferred candidate material for high-strength transparent mobile phone cover glass.

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass composition design, and relates to a high-strength transparent microcrystalline glass based on cluster composition unit design and its preparation method, especially to a Li2O–Al2O3–SiO2(LAS)-(Zn,Mg)O microcrystalline glass based on a cluster plus connecting atom model and its preparation method. Background Technology

[0002] Mobile phone cover glass refers to the ultra-thin glass located on the surface of the display screen. To improve the phone's drop resistance, heat treatment can be used to induce the crystallization of metastable glass, forming a composite material composed of crystals and a glass matrix, namely, glass-ceramics. The transparency of glass-ceramics is mainly affected by two key factors: firstly, the nucleation and crystal growth rates need to be precisely controlled to prevent excessive grain growth, thereby avoiding increased light scattering; secondly, the precipitated crystals should have birefringence properties close to those of the glass phase, meaning the refractive index of the crystals should be as close as possible to the refractive index of the glass phase. This matching is easier to achieve when the chemical compositions of the two are similar.

[0003] The transparency of a mobile phone cover glass can be expressed by its visible light transmittance. China's national standard GB / T 36259-2018, "High-aluminosilicate Glass for Touchscreen Covers," released in June 2018, requires a visible light transmittance of no less than 91.2%. For microcrystalline glass, China's national standard GB / T 45822-2025, "Transparent Microcrystalline Glass for Mobile Display Covers," released in August 2025, requires a visible light transmittance of no less than 90%. In terms of strength, the crystalline phase inside microcrystalline glass effectively inhibits crack propagation, thereby improving the glass's toughness. For example, Zerodur® microcrystalline glass, produced by Schott AG in Germany in 1968, is used in high-precision telescope lenses; its Young's modulus is 90 GPa, and its Knoop hardness is 620 HK under a 100 g load. KUNLUN GLASS is used in Huawei mobile phone cover glass in China. TM LAS microcrystalline glass, produced by Chongqing Xinjing Special Glass in 2021, has Li2Si2O5 (lithium disilicate) as its main precipitated phase. The Young's modulus of this crystalline phase reaches 80 GPa. Although this value is not much different from that of the glass matrix, the crystal can hinder crack propagation. As a result, after chemical strengthening treatment, the hardness of the glass is improved by 28% compared to the glassy state, reaching 720 HV. At the same time, it still maintains 91% visible light transmittance at a thickness of 0.65 mm, showing excellent comprehensive performance.

[0004] To further enhance the overall performance of this glass-ceramic system, a conceivable approach is to introduce a high-elastic-modulus nanoprecipitate. Based on the traditional LAS system, a spinel phase with a high elastic modulus (240 GPa) is introduced, along with divalent metal ions (Zn). 2+ and Mg 2+ This increases the aluminum content, forming a LAS-(Zn,Mg)O composite system, thereby enhancing the mechanical properties of the material. It is noteworthy that the effective precipitation of spinel depends on the addition of a nucleating agent. Seidel et al., in their study of LAS-(Zn,Mg)O (High-strength, translucent glass-ceramics in the system MgO-ZnO-Al2O3-SiO2-ZrO2, 2017, Vol. 37, pp. 2685-2694), showed that when the content of the nucleating agent ZrO2 in the glass composition was less than or equal to 4 mol%, the formation of (Zn,Mg)Al2O4 was not observed. This phenomenon is mainly attributed to the formation of β-quartz solid solution, which raises the glass transition temperature (Tg) of the glass to approximately 960 °C. At this temperature, during heat treatment, Mg... 2+ And Al 3+ The diffusion of the nucleation phase is significantly hindered, resulting in insufficient nucleation rate and thus inhibiting the formation of the spinel phase.

[0005] As early as 1932, research on LAS-ZnO began. Bunting, in his *Bureau of Standards Journal of Research* (Phase equilibria in the system SiO2-ZnO-Al2O3, Vol. 8, 1932, p. 279), attempted to introduce divalent cations into the glass and systematically studied the phase equilibrium of this system. He used optical metallography to observe the precipitated phases and drew the phase diagram of the system accordingly. Building on this foundation, numerous researchers subsequently conducted in-depth explorations into the glass composition and crystallization behavior. Li et al., in their study "Journal de Physique Colloques" (An investigation of relationship between phase separation and crystallization of ZnO-Al2O3-SiO2 glasses, Vol. 43, 1982, C9-231-C9-234), discovered that transparent glass could be successfully prepared by air quenching within a composition range of 40-60 mol% SiO2, 10-20 mol% Al2O3, and 20-50 mol% ZnO. The DTA exothermic peak of the glass was determined using TEM and XRD techniques. The results showed that the exothermic peak at approximately 900 °C corresponded to a β-quartz solid solution, while at 1000 °C, this solid solution decomposed into wurtzite, spinel, and cristobalite phases. Hansson et al., in *Metallurgical and Materials Transactions B* (A reinvestigation of phase equilibria in the system Al₂O₃-SiO₂-ZnO, Vol. 36, 2005, pp. 187-193), re-examined this system and determined its phase composition using electron probe microanalysis (EPMA). They found that when the Al₂O₃ content was less than 10 mol%, Zn₂SiO₄ (zinc siliceous mineral) formed in the system; and when the ZnO content was less than 7 mol%, Al₆Si₂O₄ formed. 13(Mullite); the spinel phase can only form when the contents of ZnO and Al2O3 exceed these critical values. Cormier et al., in the *Journal of Non-Crystalline Solids* (Vitrification, crystallization behavior and structure of zinc aluminosilicate glasses, 2021, Vol. 555, pp. 120609), further refined the phase diagram study, focusing on its vitrification formation region and crystallization behavior. Their results show that at 950 °C, the zinc spinel phase dominates the precipitated phase. These research findings provide important theoretical basis for optimizing composition and heat treatment processes.

[0006] While the rich elemental composition opens up endless possibilities for the properties of glasses, such multi-component systems involve structure, composition, and process parameters. Therefore, empirical potentials play a decisive role in simulation results in molecular dynamics (MD) simulations, but achieving sufficient coverage of numerous systems remains challenging. Although Du et al. (Journal of the American Ceramic Society, 2011, Vol. 94, pp. 2393-2401) developed partial covalent potentials applicable to silicate, aluminate, and phosphate oxide systems, achieving adequate coverage of numerous systems remains a challenge. Currently used machine learning methods include purely empirical models and physics-based models. Purely empirical models require large amounts of high-quality data for reliability assessment, while physics-based models, although able to deduce phenomenological models from physical principles, still rely on empirically fitted parameters. More importantly, for glass-ceramics, not only must the glass-forming process be compatible with existing glass manufacturing techniques, but also sufficient crystallization must be precisely controlled to form a phase with a unique nano-precipitation structure. Therefore, deriving the corresponding composition based on the desired properties and realizing a quantified compositional design model remains a complex and challenging process. The core scientific challenge lies in the inability to clearly define the constituent units within the complex system; without these constituent units, it is difficult to achieve a rational design of the glass formulation.

[0007] Therefore, by introducing a cluster-plus-connection atomic model for silicate glass, the key point is that the glass composition is expressed as a 16-unit composition formula. ,in , and These represent monovalent, trivalent, and tetravalent cations, respectively. To introduce the zinc oxide component, additional units composed of divalent and tetravalent cations were introduced into the trivalent structural unit. Subsequently, by combining commercial LAS microcrystalline glass with the ZnO–Al2O3–SiO2 (ZAS) phase diagram, the composition range of monovalent and divalent ions was determined, and a formulation for LAS-(Zn,Mg)O microcrystalline glass was proposed based on the cluster unit method. Finally, a high-strength transparent microcrystalline glass with a transmittance of around 90% at a thickness of 0.65 mm was obtained. By optimizing the arrangement of the cluster units, the mechanical and optical properties of the material can be further improved, providing theoretical guidance for the development and application of novel high-performance glasses. Summary of the Invention

[0008] In glass-ceramic systems, strictly adhering to the stoichiometry of the precipitated phases in composition design simplifies formulation but leads to severe phase separation. Furthermore, such formulations often exhibit high melting points and high-temperature, high-viscosity characteristics, significantly increasing the difficulty of melting and forming processes. All current glasses require the addition of multiple elemental oxides to silica glass, which lowers the glass's threshold (Tm) and viscosity, making it easier to manufacture. For example, float glass requires ensuring its spread during flow. Moreover, to guarantee excellent gas permeability (GFA) in the system, formulation design typically requires the compositions of the two precipitated phases to be close to the eutectic point to maintain multiphase coexistence (with a possible bias towards one dominant phase). Otherwise, the precipitated phases are easily confined to a single-phase structure, leading to phase separation or tending towards chemically proximal separation, as seen in filled β-quartz solid solutions. However, the feasibility of the manufacturing process requires that the formulation not precisely stop at the eutectic point but rather be located in a specific region near the eutectic composition. To simultaneously achieve low melting point, moderate viscosity, and excellent GFA, it is necessary to combine multiple components based on several component units and precisely control the number and proportion of components.

[0009] To address the problems existing in the prior art, this invention provides a high-strength transparent microcrystalline glass based on cluster component unit design and its preparation method. This invention introduces ZnO and MgO into the LAS matrix, enabling the precipitation of high-modulus (Mg,Zn)Al₂O₄ spinel and LiAlSi₂O₆ spodumene phases, thereby improving the mechanical properties of the microcrystalline glass. Simultaneously, since the average grain size of the precipitated phases is approximately 10 nm, the grains are uniformly distributed and exhibit no significant agglomeration, maintaining the optical transparency of the microcrystalline glass. The high-strength transparent microcrystalline glass prepared by this invention exhibits typical performance indicators: visible light transmittance of 88%~92% at a thickness of 0.65 mm, and a Vickers hardness in the range of 740~879 HV. It combines excellent comprehensive mechanical properties with high light transmittance, meeting the requirements of GB / T45822-2025 for visible light transmittance of microcrystalline glass, and can be considered a preferred candidate material for high-strength transparent mobile phone cover glass.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Based on the cluster-plus-connection atom model independently developed by our research group, we propose a quantifiable composition design method for designing high-strength, transparent Li₂O-Al₂O₃-SiO₂-(Zn,Mg)O (LAS-(Zn,Mg)O) microcrystalline glass. From the perspective of glass system classification, this material belongs to the silicate glass system. In previous studies, we constructed supercluster units {Si₂O₄} targeting the main precipitated phase β-SiO₂ in silicate glasses. 16 (Contains 32 cation sites). By replacing Si with Li, Na, Mg, Zn (network modifier), Al (network forming agent), and Zr, Ti (nucleating agent), this invention proposes for the first time and applies to the 16-unit composition formula of multi-component LAS-(Zn,Mg)O microcrystalline glass: {(Li,Na)2O} n / {(Si,Zr,Ti)O2} n -{(Li,Na) 2 / 3 (Si,Zr,Ti) 4 / 3 O3} h {(Mg,Zn)(Si,Zr,Ti)O3} k {Al2O3} l ,in h + k + l + n = 16. The units after the "-" ensure that the average cation valence state is 3 (each unit has 2 cations), which is consistent with the disordered network model of silicate glass proposed by Zachariasen in the Journal of the American Chemical Society (The atomic arrangement in glass, 1932, Vol. 50, pp. 3841-3851): the average cation valence state is 3 to 4 or slightly lower than 3. The units before the "-" are used to adjust the degree of deviation from the valence state of 3.

[0011] The high-strength transparent glass-ceramic described is a LAS-(Zn,Mg)O system, whose components include Li₂O, Na₂O, ZnO, MgO, Al₂O₃, SiO₂, ZrO₂, and TiO₂ oxides. By summarizing the compositional characteristics of historically commercially available LAS glass-ceramics and the constraints determined by their melting processes, the number of 16-unit compositional formulas ranges from {(Si,Zr,Ti)O₂}. 0~1 -{(Li,Na) 2 / 3 (Si,Zr,Ti) 4 / 3 O3} 3~9 {(Mg,Zn)(Si,Zr,Ti)O3}2~7 {Al2O3} 4~6 The corresponding mass percentages are as follows: (0.8~2.5) wt% Li2O, (1.6~5.3) wt% Na2O, (9.3~25.9) wt% ZnO, (0.1~14.3) wt% MgO, (23.3~32.4) wt% Al2O3, (31.8~48.0) wt% SiO2, (3.3~7.0) wt% ZrO2, and (2.1~4.5) wt% TiO2.

[0012] Furthermore, the oxides in the high-strength transparent microcrystalline glass satisfy the following synergistic variation relationships: 1.2 ≤ Li2O + 0.32Na2O ≤ 4.3 wt%; 47.9 ≤ ZnO + 2.2MgO + 1.6Al2O3 ≤ 65.8 wt%; 17.9 ≤ SiO2 + 0.59ZrO2 + 0.75TiO2 ≤ 59.8 wt%.

[0013] Furthermore, the high-strength transparent microcrystalline glass, by controlling the content of the above components, can achieve a crystallinity of 31-53 vol%, with its main precipitated phase being 16-50 vol% (Mg,Zn)Al₂O₄ spinel phase, accompanied by 0-10 vol% LiAlSi₂O₆ spodumene phase and 2-5 vol% ZrTiO₄ zirconium titanate co-precipitation. The average size of the precipitated grains is 6-20 nm.

[0014] Furthermore, the typical properties of the high-strength transparent microcrystalline glass are: visible light transmittance of 88%~92% at a thickness of 0.65 mm, and its Vickers hardness is in the range of 740~879 HV.

[0015] A method for preparing high-strength transparent glass-ceramics based on cluster component unit design includes the following steps: Step 1: Weigh the analytical grade raw materials according to the mass percentage composition range of each oxide and mix them evenly to obtain the mixed raw materials.

[0016] Step 2: Place the mixed raw materials in a quartz crucible, first put it into a high-temperature pit furnace preheated to 1200~1400℃ and hold for 1~2 h, then raise the temperature to 1600~1650℃ at a heating rate of 10 ℃ / min and hold for 2~4 h to fully melt the mixed raw materials and obtain glass melt; Step 3: Pour the molten glass onto a chilled iron plate, and then quickly transfer it to a muffle furnace at 500~600 ℃ for air cooling annealing to eliminate internal stress in the glass and obtain a glass matrix; the air cooling annealing time is 5~6 hours. Step 4: Heat treatment of the glass substrate: First, nucleate the substrate by holding it at 710~750℃ for 1~3 h, and then crystallize it by holding it at 800~840℃ for 1~2 h, finally obtaining high-strength transparent microcrystalline glass.

[0017] The design principle of this invention is as follows: The purpose of this invention is to provide a quantifiable composition design model and to design a high-strength transparent LAS-(Zn,Mg)O microcrystalline glass for mobile phone cover plates. This model originates from the cluster plus connecting atom model independently developed by our research group. This model can be used to define the compositional unit of any component. Its idea is based on local structure. It assumes that a central atom is introduced into a uniform electronic potential field. To minimize the system energy, surrounding atoms tend to aggregate in the first negative potential energy region, forming the first nearest-neighbor cluster, [central atom - shell atom]. When the number of attracted atoms increases to a certain extent, repulsion occurs between the atoms, prompting the next nearest neighbors to form several adjacent "connecting" atoms in the first positive potential energy region to maintain electroneutrality. Thus, the cluster unit can be written as: [central atom - shell atom] (connecting atom). Calculations show that this charge balance position is exactly at 1.764 Friedel oscillation wavelengths. λ Fr At this point, combined with the number of atoms per unit volume ρ a This allows us to determine the constituent carriers of the overall structure, with the number of atoms ranging from (4π / 3)(1.764×) λ Fr ) 3 ρ a express.

[0018] In previous work, this model analyzed the main precipitated phase β-SiO2 in silicate glass, and the cluster unit can be represented as [Si-O4]Si1=[O-Si2]O3={Si2O4}. Here, the hyphen "-" represents the separation between the central atom and its first nearest neighbor; square brackets "[ ]" represent clusters, and atoms connected to the cluster outside the brackets are considered second nearest neighbors; overall, the structure defined by curly braces "{}" represents the cluster unit. Since simple cluster units cannot be doped with other cations, it is necessary to define the spatial stacking form of {Si2O4}, that is, to construct the supercluster unit [{Si2O4}-{Si2O4}. 12 ]{Si2O4}3={Si2O4} 16 This is the component carrier of silicon dioxide glass.

[0019] Combining the disordered network model of silicate glass proposed by Zachariasen in the 1930s, which states that each nearest-neighbor cluster centered on a cation is surrounded by at least three bridging oxygen atoms, thus the average cation valence state is between 3 and 4 (which can be reduced to less than 3 by introducing a large amount of monovalent alkali metal as a flux). This invention proposes for the first time a 16-unit composition formula containing 32 cations: This construction is based on the following considerations: through regulation n The value of can cause the average cation valence state to fluctuate moderately around the value of 3; silicate glass is composed of a variety of oxides and can be regarded as a doping system of cations with different valence states; by using {Si2O4} 16 Replacing Si with other cations in the matrix allows for component substitution while maintaining the total number of cations in the 16-cluster unit formulation.

[0020] In a 16-unit composition, when the average cation valence exceeds 3, the n tetravalent units are composed of tetravalent cations Si. 4+ Zr 4+ Ti 4+ Composition, Writing The trivalent unit is composed of different combinations of cations (ensuring that the average cation valence state of each unit is 3 while ensuring that each unit contains 2 cations), namely: h A unit consisting of a combination of monovalent and tetravalent cations is written as = .

[0021] k A unit consisting of a combination of divalent and tetravalent cations, written as = .

[0022] l A trivalent cation unit, written as = .

[0023] The preparation of high-strength LAS-(Zn,Mg)O glass-ceramics requires meeting the following conditions: First, the chemical composition of the precipitated phase must be as consistent as possible with the parent glass to effectively reduce birefringence and ensure glass transparency. Second, the glass composition must contain monovalent ion units to achieve chemical strengthening during ion exchange. Furthermore, an appropriate amount of nucleating agent needs to be introduced to promote the precipitation process and ensure that the precipitated phase has a small, uniform, and dense grain size. Therefore, the number of each unit must be strictly controlled and optimized to achieve high strength performance while maintaining overall glass transparency.

[0024] In the LAS system, Li₂O, as a key component of the precipitated phase, not only effectively lowers the glass melting point to 1500 °C but also provides the necessary preconditions for subsequent chemical strengthening. This property has been verified and successfully applied in high-alumina cover glass produced by Schott AG in Germany. The typical mass composition of this glass is: 3.7Li₂O-0.2Na₂O-0.6K₂O-1.6ZnO-1MgO-25.4Al₂O₃-0.5As₂O₃-55.7SiO₂-1.8ZrO₂-2.3TiO₂-7.2P₂O₅ (wt%). After appropriate crystallization treatment, the resulting microcrystalline glass exhibits a Vickers hardness of approximately 630 HV, indicating its excellent mechanical properties. This composition is written in 16-element composition formula as follows: Similarly, regarding historically commercially available LAS microcrystalline glass (Corning Vision, USA)... @ Corning Ware @ Cercor @ Schott Zerodur, Germany @ Ceran @ Narumi, Japan Electronics @ Neoceram TM The number of units (N-0, etc.) is summarized and fine-tuned to obtain the number of monovalent cation units. =3~9, can be written .

[0025] Because the precipitated phase in the LAS system has a low Young's modulus, its effect on improving glass strength is not significant. Therefore, it is necessary to introduce a high-strength precipitated phase, spinel. At this point, the content of (Zn,Mg)O should be increased. However, due to the low average cation valence of spinel (2.67), it is difficult for it to directly form glass. Therefore, the content of (Zn,Mg)O needs to be appropriately limited. According to the ZAS phase diagram, at a liquidus temperature of 1650 ℃ and satisfying the spinel cluster unit {(Zn,Mg)Al2O4}, i.e., ZnO:Al2O3=1:1, the divalent ion content is approximately 20 mol%, and the trivalent ion content is approximately 40 mol%. Under the 16-unit cation composition formula... and The concentration falls within the range of 4 to 6. Based on this, by adjusting the number of these two types of units, the precipitation amount of (Zn,Mg)Al₂O₄ can be changed, thereby controlling the strength and optical properties of the material. Finally, the 16-unit composition formula of the embodiment can be determined as follows: .

[0026] Within a framework of 16 units, the cation range is defined as follows: Li 1~3 Na 1~3(Total 2-6), among which lithium ions and sodium ions have a key impact on the precipitation, melting temperature, and two-step chemical strengthening effect of LiAlSi2O6; Zn 2~6 Mg 0~4 (A total of 2-7, of which 2-6 divalent ions are incorporated into the {(Zn,Mg)Al2O4} spinel cluster unit), including some Zn 2+ Replacing spinel with magnesium ions lowers its refractive index and enhances its mechanical strength, thus enabling the development of transparent and high-strength glass-ceramics; Al 8~12 Si 10~14 Zr 0~1 Ti 0~1 (Among them, trivalent and tetravalent cations are the main network formers, accounting for nearly two-thirds of the total 32 cations). Zr and Ti, as nucleating agents, can significantly promote volume crystallization and inhibit surface crystallization. At this time, the spinel grain size can be stably controlled at about 10 nm, which is much smaller than the wavelength of visible light. This is of great significance for obtaining microcrystalline glass with both excellent optical properties and high transparency. Finally, the cationic formula of the embodiment was determined to be Li. 1~ 3Na 1~3 Zn 2~6 Mg 0~4 Al 8~12 Si 10~14 Zr 0~1 Ti 0~1 The corresponding mass percentage composition range of the oxide raw materials is as follows: (0.8~2.5) wt% Li2O, (1.6~5.3) wt% Na2O, (9.3~25.9) wt% ZnO, (0.1~14.3) wt% MgO, (23.3~32.4) wt% Al2O3, (31.8~48.0) wt% SiO2, (3.3~7.0) wt% ZrO2, and (2.1~4.5) wt% TiO2. Furthermore, the above-mentioned microcrystalline glass components satisfy the following synergistic variation relationships: 1.2 ≤ Li2O + 0.32Na2O ≤ 4.3 wt%; 47.9 ≤ ZnO + 2.2MgO + 1.6Al2O3 ≤ 65.8 wt%; 17.9 ≤ SiO2 + 0.59ZrO2 + 0.75TiO2 ≤ 59.8 wt%.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, based on the cluster-plus-connecting-atom model previously proposed and validated by our research group (a known method), is the first to improve and propose a 16-component formulation of silicate glass with 32 cations, achieving quantitative design of multi-component LAS-(Zn,Mg)O microcrystalline glass formulations. It fundamentally solves the problem of multi-component combination of several component units and enables precise control of component quantities, thereby altering the process parameters, transparency, and strength of the microcrystalline glass. Specifically: (1) Based on historical commercial glass, the following conclusions were drawn. =3~9, and introduce Li + / Na + Ions, while optimizing process parameters such as melting temperature and two-step chemical strengthening, to achieve performance regulation.

[0028] (2) Introduction and adjustment The number of nano-precipitates affects the amount of spinel precipitated. This nanoprecipitate can reduce the refractive index difference with the glass matrix, thereby improving transparency and significantly enhancing crystal phase rigidity and overall mechanical strength.

[0029] (3) The LAS-(Zn,Mg)O microcrystalline glass based on cluster units exhibits excellent transparency and high strength. Differential scanning calorimetry (DSC) results show that the optimal crystallization process is nucleation at 730 ℃ for 3 h, followed by crystallization at 820 ℃ for 1 h. The visible light transmittance of the sample at a thickness of 0.65 mm can reach 88%~92%, and its Vickers hardness is in the range of 740~879 HV. Among them, the sample that achieves the nano-precipitation of {(Mg,Zn)Al2O4}5 spinel units has a crystallinity of about 50 vol%, and even without chemical strengthening, its hardness is still higher than that of KUNLUNGLASS currently used in Huawei mobile phone cover glass in China. TM Increased by approximately 20%. Attached Figure Description

[0030] Figure 1 The FESEM image of the glass-ceramic prepared in Example 1 shows that the grain size is 20 nm and exhibits obvious agglomeration. The crystal type is mainly composed of (Mg,Zn)Al2O4 spinel phase (about 16 vol%) and LiAlSi2O6 phase (about 10 vol%), with about 5 vol% of ZrTiO4 nucleation phase present. Figure 2 FESEM morphology of the glass-ceramic prepared in Example 2: the grain size is about 6 nm, with no obvious agglomeration; the crystallinity is about 38 vol%, the main precipitate is about 31 vol% (Mg,Zn)Al2O4, accompanied by about 6 vol% LiAlSi2O6 and 2 vol% ZrTiO4; Figure 3 The FESEM image of the glass-ceramic prepared in Example 3 shows that the grain size is about 12 nm and no obvious agglomeration is observed. The crystallinity is about 53 vol%. The main precipitate is about 50 vol% (Mg,Zn)Al2O4, accompanied by about 3 vol% ZrTiO4. LiAlSi2O6 was not detected (i.e., 0 vol% LiAlSi2O6). Detailed Implementation

[0031] The present invention will be further described below with reference to specific implementation examples.

[0032] Example 1 Weigh out 100 g of analytical grade raw materials according to the following mass ratios: 2.5Li₂O-5.3Na₂O-9.3ZnO-0.1MgO-23.3Al₂O₃-48.0SiO₂-7.0ZrO₂-4.5TiO₂. Mix thoroughly and place in a quartz crucible. First, place the raw materials in a high-temperature pit furnace preheated to 1200℃ and hold for 1 hour. Then, increase the temperature to 1600℃ at a rate of 10℃ / min and hold for 2 hours to ensure thorough mixing and melting of the raw materials. Finally, pour the molten glass onto a room-temperature iron plate and quickly transfer it to a muffle furnace at 500℃ for 5 hours of air-cooling annealing to eliminate stress generated inside the glass during rapid cooling.

[0033] The optimal process was determined based on the characteristic temperature points of the DSC curve: nucleation was performed by holding at 750℃ for 1 hour (corresponding to the glass transition temperature Tg+50℃), and crystallization was achieved by holding at 840℃ for 1 hour (corresponding to the initial crystallization temperature Ton1), finally obtaining the microcrystalline glass sample.

[0034] The microstructure and property analysis methods of the LAS-(Zn,Mg)O glass-ceramics involved in this application are as follows: X-ray diffraction (XRD, Empyrean) analysis showed a crystallinity of approximately 31 vol%. The main precipitates were 16 vol% (Mg,Zn)Al₂O₄ (corresponding to PDF#73-1959 and PDF#82-1538) and 10 vol% LiAlSi₂O₆ (PDF#73-2336), with 5 vol% ZrTiO₄ (PDF#74-1504) precipitated as a nucleating agent. Field emission scanning electron microscopy (FESEM, Zeiss SUPRA 55) observations showed a grain size of approximately 20 nm with significant agglomeration. Figure 1 As shown.

[0035] The Vickers hardness was measured using a microhardness tester (HXD-1000TMC / LCD) under a loading pressure of 100 g and a loading time of 10 s. The average value of 15 points was taken to obtain the Vickers hardness to characterize the material strength. At the same time, the visible light transmittance at a thickness of 0.65 mm was obtained using a spectrophotometer (ShimadzuUV 26001).

[0036] Example 1 exhibits a visible light transmittance of 88% and a Vickers hardness of 740 HV at a thickness of 0.65 mm. This is in contrast to KUNLUNGLASS, which uses lithium disilicate as the main precipitated phase. TM In comparison, Example 1 has a lower transmittance; however, the mechanical strength of the untreated Example 1 is close to that of the chemically treated KUNLUNGLASS. TM The main reason for the above phenomenon is that a large amount of LiAlSi2O6 is precipitated in the sample. The Young's modulus of this phase is similar to that of the glass matrix, so its strengthening effect is limited. At the same time, its grain size is large, which enhances the scattering of visible light, thus leading to a decrease in transmittance.

[0037] Example 2 Weigh out 100 g of analytical grade raw materials according to the following mass fractions: 1.8Li₂O-3.5Na₂O-9.5ZnO-14.3MgO-29.8Al₂O₃-35.2SiO₂-3.6ZrO₂-2.3TiO₂. Mix them thoroughly and place them in a quartz crucible. Place the crucible in a high-temperature pit furnace preheated to 1250 °C and hold for 1.5 h. Then, increase the temperature to 1620 °C at 10 °C / min and hold for 3 h to fully melt and mix the materials. Subsequently, quickly transfer the mixture to a muffle furnace at 530 °C for air cooling annealing for 5.7 h to relieve stress. Crystallization heat treatment was performed based on the characteristic temperature points of DSC: nucleation was carried out at 730 ℃ (Tg+50 ℃) for 2 h, followed by crystallization at 830 ℃ for 1.5 h, finally yielding a microcrystalline glass with a crystallinity of approximately 38 vol%. The main precipitate was 31 vol% (Mg,Zn)Al₂O₄, accompanied by small amounts of 6 vol% LiAlSi₂O₆ and 2 vol% ZrTiO₄. FESEM observation showed that the grains were approximately 6 nm in size, uniformly distributed, and without obvious agglomeration (see...). Figure 2 ).

[0038] Example 2 showed a visible light transmittance of 90% and a Vickers hardness of 828 HV at a thickness of 0.65 mm. This is because (Mg,Zn)Al2O4, as the main precipitated phase, has a high hardness (natural spinel has a Mohs hardness of 8, and quartz glass has a Mohs hardness of 7), thus playing a dominant role in precipitated phase strengthening. Furthermore, due to the small average grain size, even though the composition of (Mg,Zn)Al2O4 differs significantly from the glass phase, resulting in a large difference in refractive index, the small crystal size still reduces light scattering and lowers turbidity.

[0039] Example 3 Weigh out 100 g of analytical grade raw materials according to the following mass fractions: 0.8Li₂O-1.6Na₂O-25.9ZnO-2.1MgO-32.39Al₂O₃-31.81SiO₂-3.3ZrO₂-2.1TiO₂. Mix them thoroughly and place them in a quartz crucible. Place the crucible in a high-temperature pit furnace preheated to 1400℃ and hold for 2 h. Then, increase the temperature to 1650℃ at 10℃ / min and hold for 4 h to fully melt and mix. Subsequently, quickly transfer the mixture to a muffle furnace at 600℃ for air cooling annealing for 6 h to relieve stress. Crystallization heat treatment was performed based on the characteristic temperature points of DSC: nucleation was carried out at 750 ℃ ​​(Tg+50 ℃) for 3 h, followed by crystallization at 840 ℃ for 2 h, finally yielding a microcrystalline glass with a crystallinity of approximately 53 vol%. The main precipitate was 50 vol% (Mg,Zn)Al₂O₄, accompanied by 3 vol% ZrTiO₄, with no detected LiAlSi₂O₆ (i.e., 0 vol% LiAlSi₂O₆). FESEM observation showed that the grains were approximately 12 nm in size, uniformly distributed, and without obvious agglomeration (see...). Figure 3 ).

[0040] Example 3: Even without chemical strengthening, this microcrystalline glass still exhibits a Vickers hardness of 879 HV, which is higher than that of the chemically strengthened Huawei KUNLUN GLASS. TM It is about 20% higher; at the same time, with a thickness of 0.65 mm, the visible light transmittance can still be maintained at 92%, which meets the requirements of GB / T 45822-2025 for microcrystalline glass for display cover plates.

[0041] The above embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A high-strength transparent microcrystalline glass designed based on cluster component units, wherein the high-strength transparent microcrystalline glass belongs to the silicate glass system, characterized in that, The high-strength transparent glass-ceramic is based on the LAS-(Zn,Mg)O system, and its components include Li₂O, Na₂O, ZnO, MgO, Al₂O₃, SiO₂, ZrO₂, and TiO₂ oxides; the number of 16-unit components in the high-strength transparent glass-ceramic ranges from {(Si,Zr,Ti)O₂}. 0~1 -{(Li,Na) 2 / 3 (Si,Zr,Ti) 4 / 3 O3} 3~9 {(Mg,Zn)(Si,Zr,Ti)O3} 2~7 {Al2O3} 4~6 The corresponding mass percentages are as follows: (0.8~2.5)wt%Li2O, (1.6~5.3)wt%Na2O, (9.3~25.9)wt%ZnO, (0.1~14.3)wt%MgO, (23.3~32.4)wt%Al2O3, (31.8~48.0)wt%SiO2, (3.3~7.0)wt%ZrO2, and (2.1~4.5)wt%TiO2.

2. The high-strength transparent microcrystalline glass based on cluster component unit design according to claim 1, characterized in that, The oxides in the high-strength transparent microcrystalline glass satisfy the following synergistic variation relationships: 1.2≤Li2O+0.32Na2O≤4.3wt%; 47.9≤ZnO+2.2MgO+1.6Al2O3≤65.8wt%; 17.9≤SiO2+0.59ZrO2+0.75TiO2≤59.8wt%.

3. The high-strength transparent microcrystalline glass based on cluster component unit design according to claim 1, characterized in that, The high-strength transparent microcrystalline glass, by controlling the composition content, can have its crystallinity controlled at 31~53 vol%. Its main precipitated phase is 16~50 vol% (Mg,Zn)Al2O4 spinel phase, accompanied by 0~10 vol% LiAlSi2O6 spodumene phase and 2~5 vol% ZrTiO4 zirconium titanate co-precipitation.

4. A high-strength transparent microcrystalline glass based on cluster component unit design according to claim 3, characterized in that, The average grain size of the precipitated phase is 6~20 nm.

5. A high-strength transparent microcrystalline glass based on cluster component unit design according to claim 1, characterized in that, The typical properties of the high-strength transparent microcrystalline glass are: visible light transmittance of 88%~92% at a thickness of 0.65mm, and Vickers hardness in the range of 740~879HV.

6. A method for preparing a high-strength transparent microcrystalline glass based on cluster component unit design as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Weigh the analytical grade raw materials according to the mass percentage composition range of each oxide and mix them evenly to obtain a mixed raw material; Step 2: Place the mixed raw materials in a quartz crucible, first put it into a high-temperature pit furnace preheated to 1200~1400℃ and keep it at that temperature for 1~2 hours, then raise the temperature to 1600~1650℃ and keep it at that temperature for 2~4 hours to fully melt the mixed raw materials and obtain molten glass. Step 3: Pour the molten glass onto a cold iron plate, and then quickly transfer it to a muffle furnace at 500~600℃ for air cooling annealing to obtain a glass matrix; Step 4: Heat treatment of the glass substrate: First, nucleate the substrate by holding it at 710~750℃ for 1~3 hours, and then crystallize it by holding it at 800~840℃ for 1~2 hours to obtain high-strength transparent microcrystalline glass.

7. The method for preparing a high-strength transparent microcrystalline glass based on cluster component unit design according to claim 6, characterized in that, In step 2, the heating rate is 10℃ / min.

8. The method for preparing a high-strength transparent microcrystalline glass based on cluster component unit design according to claim 6, characterized in that, In step 3, the air-cooled annealing time is 5-6 hours.

Images