Lithium-aluminum-silicon chemically tempered glass, and preparation method and application thereof

Abstract

This invention belongs to the field of glass technology, and particularly relates to a lithium aluminum silicon chemically tempered glass, its preparation method, and its applications. The lithium aluminum silicon chemically tempered glass comprises the following components by mass percentage: 55-60% SiO2, 15-21% Al2O3, 4-6% Li2O, 2-4% Na2O, 2-4% K2O, 3-5% MgO, 1% ZrO2, 3-5% Y2O3, and 1-3% Sb2O3. Simultaneously, the mass percentages of each component satisfy the formula constraints of the ion exchange capacity index G, the strengthening index Q, and the stability coefficient S. This invention, through the design of the glass composition and content and the introduction of the above three synergistic control formulas, results in a lithium aluminum silicon chemically tempered glass with excellent impact resistance, good strengthening properties, high strength, and excellent overall performance, making it suitable for application in the field of cover glass.

Description

Technical Field

[0001] This invention belongs to the field of glass technology, and in particular relates to a lithium aluminum silicon chemically tempered glass, its preparation method, and its application. Background Technology

[0002] In fields such as displays, window glass, optical equipment, and industrial instruments, extremely high requirements are placed on the strength, hardness, and impact resistance of cover glass materials. Chemical strengthening is key to improving the mechanical properties of glass. Its principle involves high-temperature ion exchange, which replaces smaller alkali metal ions in the glass surface with larger alkali metal ions in the molten salt, thereby forming a compressive stress layer on the surface. Traditional soda-lime-silica glass has significant drawbacks in this process, such as a slow ion exchange rate, a shallow stress layer depth, and limited surface compressive stress. This results in the strengthened glass still failing to meet the hardness and impact resistance requirements of high-end applications.

[0003] To improve strengthening properties, lithium aluminum silicon glass has attracted widespread attention. In this system, SiO2, with its silicon-oxygen tetrahedral structure, is the main component forming the glass network structure and also the main component improving the glass's chemical durability. The introduction of Li2O not only helps to reduce the coefficient of thermal expansion, but also... + Ions are key active components in the ion exchange process and directly affect the strengthening effect. Introducing Al2O3 can accelerate the speed and depth of ion exchange and improve the strengthening efficiency, but the introduction of Al2O3 will also increase the difficulty of glass melting.

[0004] Chinese invention patent application CN114031293A discloses the composition of lithium aluminum silicon glass, which, by mass percentage of oxides, includes: SiO2 58-68%, Al2O3 18-23%, Na2O 1-10%, K2O 0.5-5%, MgO 1-2%, ZrO2 1-3.5%, Li2O 2-7%, TiO2 1.5-5%, CeO2 0.5-2%, clarifying agent 0.1-2%, SiO2+Al2O3+Li2O 80-90%; Al2O3 / Na2O 2-4; TiO2 / CeO2>1.5; Al2O3 / (Na2O+Li2O) 1.2-2.0. Although the aforementioned lithium aluminum silicon glass includes components such as SiO2, Li2O, Al2O3, Na2O, K2O, MgO, ZrO2, and clarifying agents, and limits the content of each component, the range of values ​​is still limited by experience in the component ratio, which is completely inconsistent with the performance requirements of the material used in cover glass.

[0005] In lithium aluminum silicon glass systems, SiO2, Li2O, and Al2O3 do not act independently, but rather collectively determine the glass's network structure, ion exchange capacity, thermal stability, and mechanical properties. Simply increasing or decreasing the content of any one component will disrupt the glass's network structure stability, ion exchange balance, or thermodynamic stability, leading to poor strengthening effects, brittleness, or spontaneous breakage.

[0006] Therefore, how to synergistically optimize the addition of SiO2, Li2O, and Al2O3 in lithium aluminum silicon glass, while ensuring the glass can be prepared fusibly, to optimize ion exchange behavior and obtain cover glass materials with high surface compressive stress, deep stress layer, and excellent comprehensive performance, is a problem that needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to provide a lithium aluminum silicon chemically tempered glass, its preparation method, and its application, in order to solve the problem that the content of SiO2, Li2O, and Al2O3 components in lithium aluminum silicon glass cannot be synergistically optimized when it is used as a cover glass in the prior art.

[0008] To achieve the above objectives, the first aspect of the present invention provides a lithium aluminum silicon chemically tempered glass, wherein the lithium aluminum silicon chemically tempered glass comprises the following components in mass percentage: 55-60% SiO2, 15-21% Al2O3, 4-6% Li2O, 2-4% Na2O, 2-4% K2O, 3-5% MgO, 1% ZrO2, 3-5% Y2O3, and 1-3% Sb2O3; According to Formula 1, the ion exchange capacity index G satisfies 0.42≤G≤0.59; Formula 1, In the formula, [Li2O], [Al2O3], [K2O], and [Na2O] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass, respectively; The strengthening index Q calculated according to Formula 2 satisfies 5.0 ≤ Q ≤ 7.0; Q=[Li2O]+0.5×[Na2O]+0.3×[ZrO2] 0.2×[MgO] Formula 2, In the formula, [Li2O], [Na2O], [ZrO2], and [MgO] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass, respectively; The stability coefficient S calculated according to formula 3 satisfies 42≤S≤48; S = [SiO2] + 0.7 × [Al2O3] 3.5×([Li2O]+[Na2O]) formula 3, In the formula, [SiO2], [Al2O3], [Li2O], and [Na2O] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass.

[0009] By adopting the above technical solution, the composition and content of each component of lithium aluminum silicon glass were comprehensively designed, with each component having its specific function. SiO2 is the main component forming the glass network structure. The Si-O covalent bonds connecting silicon and oxygen atoms in SiO2 are very strong. Therefore, adding SiO2 to glass products can endow them with physicochemical properties such as high strength, high chemical stability, and low coefficient of thermal expansion. However, if the mass percentage of SiO2 is too high, a higher temperature is required to melt the glass, and refining and homogenization require a longer time. To ensure the molten state of SiO2, its content must be controlled below 60%.

[0010] Al₂O₃, besides SiO₂, is another component that forms the glass network structure. It exists in the glass as [SiO₄] tetrahedra, making the glass structure more complete and robust. Simultaneously, Al₂O₃ can accelerate the rate and depth of ion exchange, improve strengthening efficiency, and increase the compressive stress generated on the surface of chemically strengthened glass. The Al₂O₃ addition amount specified in this invention provides the glass product with sufficient ion exchange capacity, surface compressive stress, and stress layer depth. Excessive Al₂O₃ addition will significantly increase melt viscosity, making the glass difficult to melt, homogenize, and clarify, thus leading to adverse effects such as crystallization.

[0011] Li in Li2O + As a key element in ion exchange, Li2O can improve ion exchange efficiency. In this invention, the amount of Li2O added is limited to 4% or more. However, if the amount of Li2O added is too high, it will lead to a decrease in the chemical stability of the glass, an increase in the coefficient of thermal expansion, and a risk of spontaneous explosion. Therefore, in this invention, the amount of Li2O added is limited to 4-6%.

[0012] In lithium-aluminum-silicon glass systems, SiO2, Li2O, and Al2O3 do not exist independently. Optimization of their contents is not done by adjusting individual components, but rather by comprehensively and synergistically optimizing the contents of each component. Regarding the framework structure, SiO2, as the main component of the glass network structure, directly determines the basic degree of polymerization. Al2O3 requires sufficient Li2O to provide charge compensation to stably form [AlO4] tetrahedra, thereby repairing and strengthening the network. However, if the Al2O3 / Li2O molar ratio is too high, some Al... 3+The transformation to [AlO6] octahedrons actually weakens the structure. Regarding ion exchange capacity, excessive SiO2 or Al2O3 can make the glass network structure too dense, hindering exchange. In terms of thermal stability, increasing SiO2 and Al2O3 can raise the glass transition temperature and lower the coefficient of thermal expansion, while Li2O promotes crystallization and regulates the coefficient of thermal expansion by reducing melt viscosity; the ratio of these three directly affects the glass's crystal phase. Regarding mechanical properties, high SiO2 and Al2O3 can improve the glass's hardness and rigidity, but excessive Li2O will reduce hardness due to excessive depolymerization. This invention, through synergistic optimization of the content of SiO2, Li2O, and Al2O3 in the lithium aluminum silicon glass system, enables the glass product to ultimately achieve high strength, thermal stability, and ion exchange capacity.

[0013] Na₂O and K₂O are mainly used as co-solvents to reduce viscosity and improve chemical forging efficiency. This invention limits their content to less than 4% to avoid excessive introduction of them, which could lead to Li… + The relative dilution is detrimental to the chemical fortification process.

[0014] MgO, as a glass network modifier, can effectively improve the thermal stability of glass. ZrO2, as a reinforcing agent, can improve chemical stability, reduce stress relaxation at high temperatures, improve glass brittleness, and combine with Al2O3 in lithium aluminosilicate glass to enhance the strengthening effect. Rare earth ions in Y2O3, as a network modifier, can promote a more compact glass network structure, thereby improving the elastic modulus, hardness, and thermal shock resistance of glass products, reducing the coefficient of thermal expansion, and improving high-temperature stability. This invention specifically limits the addition amount of Y2O3 to 3-5%; excessive addition may lead to crystallization problems.

[0015] Sb2O3 is mainly used as a clarifying agent. It decomposes through redox reactions to release oxygen. The oxygen diffuses into the microbubbles in the molten glass, causing the bubbles to merge, rise, and escape. This effectively reduces internal bubble defects in the glass, improves the transparency and homogenization of the glass, and avoids uneven tempering stress and easy cracking caused by bubbles. At the same time, rare earth elements have a high melting point, which can reduce the glass melting temperature to a certain extent, reduce energy consumption during the melting process, and improve the fluidity of the molten glass, which helps to form uniform glass and avoid defects such as streaks and bubbles.

[0016] This invention not only designs each component individually and addresses the interactions between their contents, but also limits the synergistic effects. It proposes three formulas: the ion exchange capacity index, the strengthening index, and the stability coefficient. The ion exchange capacity index G adjusts the balance between Li₂O, Al₂O₃, Na₂O, and K₂O, preventing an overly dense network from hindering ion exchange and a loose structure from resulting in a shallow exchange layer. An ion exchange capacity index G between 0.42 and 0.59 controls the ion exchange rate, ensuring the tempered glass does not shatter or crack. The strengthening index Q between 5.0 and 7.0; a higher Q value corresponds to a higher CS (surface compressive stress) value and a deeper DOL (depth of ion exchange layer). This parameter is directly related to the final performance of the glass product, allowing for prediction of product performance during the formulation design stage and enabling precise control of product performance. The stability coefficient S between 42 and 48 effectively prevents spontaneous breakage and crystallization during melting, forming, or strengthening heat treatment, resulting in well-formed, non-deteriorated, and stable tempered glass.

[0017] The combined use of three formulas in this invention elevates the content of components such as SiO2, Li2O, and Al2O3 from empirical ranges to a synergistically optimized mathematical model. This not only ensures the meltability and structural stability of the glass but also significantly improves its mechanical properties after chemical strengthening, enabling lithium aluminum silicon glass to meet the stringent requirements of cover glass for high strength, high impact resistance, and high abrasion resistance. The lithium aluminum silicon chemically tempered glass prepared by this invention holds promise for application in cover glass.

[0018] A second aspect of this invention provides a method for preparing lithium aluminum silicon chemically tempered glass, comprising the following steps: (1) Mix the raw materials to obtain a mixture; (2) Heat the mixture to melt it into molten glass; (3) The molten glass is cast to obtain the base glass; (4) Anneal the base glass and slice it to obtain sheet glass; (5) Chemically strengthen the sheet glass to obtain lithium aluminum silicon chemically tempered glass.

[0019] Preferably, in step (2), the heating temperature is 1570-1640℃ and the heating time is 5-6h.

[0020] Preferably, in step (3), the casting process involves first preheating the mold to 500-700°C, then pouring the molten glass into the preheated mold and allowing it to cool naturally to room temperature.

[0021] Preferably, in step (4), the annealing temperature is 500-600℃ and the annealing time is 6-10h.

[0022] Preferably, in step (5), the chemical strengthening is performed at least twice.

[0023] Preferably, in step (5), the chemical strengthening is performed twice, wherein the first chemical strengthening is to immerse the sheet glass in molten sodium nitrate, and the second chemical strengthening is to immerse the sheet glass after the first chemical strengthening in molten potassium nitrate.

[0024] Preferably, in step (5), the temperature of the first chemical strengthening is 410-440℃ and the time is 2-5h, and the temperature of the second chemical strengthening is 420-450℃ and the time is 1-3h.

[0025] By employing the above technical solution, the sheet glass is chemically strengthened twice. The first chemical strengthening is Li + with Na + Exchange, because Li + With a small ionic radius, it has relatively strong migration ability in glass networks and can interact with Na+. + A deeper exchange occurs, ultimately forming a base stress layer with a relatively deep ion layer. The second chemical strengthening process involves Na... + With K + Exchange, because K + The ionic radius of Na is greater than that of Na + and Li + They are all much larger, when the Na in the surface layer + By a larger K + After replacement, a stronger squeezing effect is generated on the outermost layer of the glass, effectively forming surface stress. The synergistic effect of the two chemical strengthening processes gives the glass product excellent scratch resistance, impact resistance, and drop resistance, resulting in better overall performance and promising applications in cover glass.

[0026] A third aspect of this invention provides an application of lithium aluminum silicon chemically tempered glass, which is used in cover glass. Cover glass is mainly used in electronic product screens, window glass, optical equipment, industrial instruments, and other fields.

[0027] The present invention adopts the above-described technical solution, and compared with the prior art, it has the following beneficial effects: (1) This invention optimizes the components and contents in lithium aluminum silicon glass and introduces three synergistic formulas, G, Q and S, to limit the contents of the corresponding components. This achieves stable melting of glass products and improves the comprehensive properties of glass products, such as impact resistance, surface compressive stress and chemical strengthening properties.

[0028] (2) The present invention processes the base glass through two chemical strengthening processes, so that the glass product has a deep stress layer and a high surface compressive stress at the same time, which makes the lithium aluminum silicon chemical tempered glass applicable to the field of cover glass. Detailed Implementation

[0029] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.

[0030] The composition and content of lithium aluminum silicon chemically tempered glass in Examples 1-4 and Comparative Examples 1-4 are shown in Tables 1 and 2.

[0031] Table 1 Composition and content of glass products in the examples

[0032] Table 2. Composition and content of glass products in the comparative examples

[0033] The formulas for calculating the ion exchange capacity index G, the enhancement index Q, and the stability coefficient S in Tables 1 and 2 are as follows: Formula 1, In the formula, [Li2O], [Al2O3], [K2O], and [Na2O] represent the mass percentages of Li2O, Al2O3, K2O, and Na2O in lithium aluminum silicon chemically tempered glass, respectively. Q=[Li2O]+0.5×[Na2O]+0.3×[ZrO2] 0.2×[MgO] Formula 2, In the formula, [Li2O], [Na2O], [ZrO2], and [MgO] are the mass percentage values ​​of Li2O, Na2O, ZrO2, and MgO in lithium aluminum silicon chemically tempered glass, respectively. S = [SiO2] + 0.7 × [Al2O3] 3.5×([Li2O]+[Na2O]) formula 3, In the formula, [SiO2], [Al2O3], [Li2O], and [Na2O] represent the mass percentages of SiO2, Al2O3, Li2O, and Na2O in lithium aluminum silicon chemically tempered glass, respectively.

[0034] The preparation methods of the glass products in the above embodiments and comparative examples include the following steps: (1) Weigh the corresponding oxide raw materials according to the proportions designed for the composition and mix them to obtain a mixture; (2) Heat the mixture at 1640℃ for 5.5h to melt it into glass liquid, and keep the glass liquid at 1600℃ for 2h to clarify and homogenize it; (3) Preheat the heat-resistant steel mold to 650°C, pour the clarified glass liquid into the preheated mold, spread it evenly and cover the entire mold, and after casting, cover the mold with a heat-insulating cover plate and let it cool naturally to room temperature to obtain the base glass. (4) The base glass is annealed at 550℃ for 8 hours, and then sliced ​​using a diamond wire cutter to obtain sheet glass. The sheet glass has the following specifications: length 145mm, width 73mm, thickness 0.55mm. (5) The sheet glass is chemically strengthened twice. The first chemical strengthening involves immersing the sheet glass in molten sodium nitrate and maintaining it at 410-440℃ for 2-5 hours. The Li in the sheet glass is then... + With sodium in sodium nitrate + The second chemical strengthening process involves immersing the glass sheet that underwent the first chemical strengthening in molten potassium nitrate and maintaining it at 420-450℃ for 1-3 hours. This process removes the Na+ from the glass sheet. + With potassium in potassium nitrate + The process involves exchange to obtain lithium aluminum silicon chemically tempered glass. Specific chemical strengthening parameters for the examples and comparative examples are shown in Table 3.

[0035] Table 3 Chemical fortification parameters of the examples and comparative examples

[0036] Test case Performance tests were conducted on the glass products of the examples and comparative examples. The sample specifications of the glass products to be tested were 145mm in length, 73mm in width, and 0.55mm in thickness. The impact strength, surface compressive stress (CS value), four-point bending strength (4PB), and sandpaper drop height were tested respectively.

[0037] The impact strength test procedure specifically refers to the falling ball impact test, which is performed according to the GB / T39814-2021 standard. The specific test procedure is as follows: Using a falling ball impact testing machine, the glass sample is placed on a sample pad. At a certain base height, a 130g steel ball is dropped freely onto the glass surface. If the glass does not break, the height of the steel ball is increased by a fixed increment, and the balls are dropped freely until the glass breaks. The breakage height is the glass's impact strength. In the falling ball impact test, the ball is made of stainless steel, weighs 130g, has a diameter of 31.5cm, starts at 20cm, and is repeated three times. If the glass does not break, the height is increased by 5cm, and the drop height after the glass breaks is recorded.

[0038] Sandpaper drop height test procedure: Use a drop tester with the glass face down and fixed horizontally on the suction cup; lay the sandpaper flat on the drop tester's base plate, with the sandpaper positioned directly below the suction cup. Specific test conditions: 180 grit sandpaper, 200g total weight, 50cm base height, increasing by 5cm, test 3 times at each height until the glass breaks.

[0039] The CS value test procedure is carried out in accordance with the standard GB / T 18144~2008: 1. Sample preparation: Prepare clean glass slides with no surface defects.

[0040] 2. Open the FSM6000 and computer software, set the parameters, place the glass slide flat on the probe, ensuring there are no air bubbles, and ensure the software image is clear before testing.

[0041] The 4PB test procedure was carried out in accordance with standard JC / T 676~1997: 1. Prepare the sample.

[0042] 2. Turn on the universal testing machine and set the parameters: span setting: outer span L1: 40mm; inner span L2: 20mm, loading rate: 0.5mm / min (low speed impact resistance for brittle glass).

[0043] 3. With the reinforced surface of the sample facing upwards, place the outer support roller in the center, align the inner pressure head with the center, and ensure there is no eccentricity or preload.

[0044] 4. Start the test, apply a constant load until fracture, and record the maximum load F (N).

[0045] 5. After the sample breaks, remove it and inspect the fracture surface (if the edge is broken, the data is invalid and the test must be repeated).

[0046] Calculate the bending strength according to Formula 4: σ=3F(L1 L2) / (2bd 2 ) Formula 4, Where: σ: bending strength (MPa); F: fracture load (N); L1: outer span (mm); L2: inner span (mm); b: sample width (mm); d: sample thickness (mm).

[0047] The test results are shown in Table 4.

[0048] Table 4 Performance test results of the examples and comparative examples

[0049] As can be seen from Table 4, the stress values ​​of both the lithium aluminum silicon glass prepared in Examples 1-4 and the lithium aluminum silicon glass prepared in Comparative Examples 1-4 were significantly higher after the second chemical strengthening than after the first chemical strengthening. This indicates that the preparation process involving multiple chemical strengthenings is very important for improving the stress value of glass products.

[0050] As can be seen from Tables 1, 2, and 4, the addition amounts of all components in Examples 1-4 are not only designed according to the content limits of a single component, but also simultaneously conform to the limits of the three formulas. This results in high ion exchange efficiency during the chemical strengthening process of the lithium aluminum silicon glass of this invention, leading to excellent strengthening performance of the glass product. It solves the problems of shallow ion exchange depth and low surface stress after glass sheet strengthening, ultimately improving the strength and impact resistance of the chemically strengthened glass, resulting in high overall performance of the glass product. The CS values ​​of the lithium aluminum silicon glass after the second chemical strengthening in all examples are 943-975 MPa, the drop ball breakage height is 45-50 cm, the four-point bending strength is 875-895 MPa, and the sandpaper drop ball height is 1900-1950 mm. This indicates that the lithium aluminum silicon chemically tempered glass prepared by this invention possesses high compressive stress, excellent impact resistance, good bending stress, and scratch resistance, exhibiting excellent overall performance. It is expected to be applied in the field of cover glass, meeting the requirements of high-end fields such as electronic products and optical equipment.

[0051] In Comparative Example 1, the amount of SiO2 added exceeded the range defined by this invention. Although the excess was not significant, the content of each component in this comparative example could not meet the constraints of the three formulas for ion exchange capacity index G, strengthening index Q, and stability coefficient S. Ultimately, the lithium aluminum silicon glass obtained in this comparative example showed significantly lower surface compressive stress, strengthening effect, and scratch resistance compared to the example. In Comparative Example 2, the amounts of K2O and Y2O3 added slightly exceeded the range defined by this invention. The lithium aluminum silicon glass prepared in this comparative example achieved a high surface compressive stress after the first chemical strengthening, which was basically the same as that of the example. However, the surface compressive stress did not increase significantly after the second chemical strengthening, indicating that chemical strengthening had little effect on improving the performance of the glass product. At the same time, although the lithium aluminum silicon glass in Comparative Example 2 could maintain a high surface compressive stress, its drop ball breakage height, four-point bending strength, and sandpaper drop height all decreased significantly, indicating that if the composition of the glass product is not optimized according to the component range defined by this invention, its overall performance cannot be improved. In Comparative Example 3, the amount of SiO2 added exceeded the limits specified in this invention. Although the component content in this comparative example met the formula constraints for the ion exchange capacity index G, it still failed to meet the formula constraints for the strengthening index Q and the stability coefficient S. Therefore, the lithium aluminum silicon glass obtained in Comparative Example 3 showed a significant decrease in compressive stress, impact resistance, flexural strength, and scratch resistance. In Comparative Example 4, the amount of Li2O added exceeded the limits specified in this invention, and the content design of other components also failed to meet the constraints of the three formulas G, Q, and S, similarly leading to a decrease in the various properties of the glass product compared to the examples.

[0052] In summary, simply adjusting the content of a single component in the glass system is insufficient to obtain high-performance lithium aluminum silicon chemically tempered glass. The constraints of the three synergistic formulas (G, Q, and S) must be simultaneously satisfied to achieve the comprehensive performance of high surface compressive stress, high impact resistance, and high abrasion resistance in the glass product. Some components in the comparative examples exceed the limits defined in this invention and cannot simultaneously satisfy the constraints of the three synergistic formulas. This results in poor strengthening effect and a high spontaneous breakage rate, making the glass unsuitable for use as cover glass.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A lithium aluminum silicon chemically tempered glass, characterized in that: The lithium aluminum silicon chemically tempered glass comprises the following components by mass percentage: 55-60% SiO2, 15-21% Al2O3, 4-6% Li2O, 2-4% Na2O, 2-4% K2O, 3-5% MgO, 1% ZrO2, 3-5% Y2O3, and 1-3% Sb2O3; The ion exchange capacity index G calculated according to Formula 1 satisfies: 0.42≤G≤0.59; Official 1, In the formula, [Li2O], [Al2O3], [K2O], and [Na2O] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass, respectively; The strengthening index Q calculated according to Formula 2 satisfies 5.0 ≤ Q ≤ 7.0; Q=[Li2O]+0.5×[Na2O]+0.3×[ZrO2] 0.2 × [MgO] Formula 2, In the formula, [Li2O], [Na2O], [ZrO2], and [MgO] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass, respectively; The stability coefficient S calculated according to formula 3 satisfies 42≤S≤48; S = [SiO2] + 0.7 × [Al2O3] 3.5 × ([Li2O] + [Na2O]) Formula 3, In the formula, [SiO2], [Al2O3], [Li2O], and [Na2O] are the mass percentage values ​​of the corresponding components in lithium aluminum silicon chemically tempered glass.

2. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 1, characterized in that: Includes the following steps: (1) Mix the raw materials to obtain a mixture; (2) Heat the mixture to melt it into molten glass; (3) The molten glass is cast to obtain the base glass; (4) Anneal the base glass and slice it to obtain sheet glass; (5) Chemically strengthen the sheet glass to obtain lithium aluminum silicon chemically tempered glass.

3. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 2, characterized in that: In step (2), the heating temperature is 1570-1640℃ and the heating time is 5-6h.

4. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 2, characterized in that: In step (3), the casting process involves first preheating the mold to 500-700℃, then pouring the molten glass into the preheated mold and allowing it to cool naturally to room temperature.

5. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 2, characterized in that: In step (4), the annealing temperature is 500-600℃ and the annealing time is 6-10h.

6. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 2, characterized in that: In step (5), the chemical strengthening is performed at least twice.

7. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 6, characterized in that: In step (5), the chemical strengthening is performed twice. The first chemical strengthening involves immersing the sheet glass in molten sodium nitrate, and the second chemical strengthening involves immersing the sheet glass after the first chemical strengthening in molten potassium nitrate.

8. The method for preparing lithium aluminum silicon chemically tempered glass according to claim 7, characterized in that: In step (5), the temperature for the first chemical strengthening is 410-440℃ and the time is 2-5h, and the temperature for the second chemical strengthening is 420-450℃ and the time is 1-3h.

9. The application of lithium aluminum silicon chemically tempered glass according to claim 1, characterized in that: Lithium-aluminum-silicon chemically tempered glass is used in cover glass.

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