Lithium-aluminum-silicon glass with high impact resistance and process for its production

Abstract

The application discloses lithium-aluminum-silicon glass with high strength and ball drop resistance and a processing technology thereof, and the lithium-aluminum-silicon glass comprises the following components: SiO2 62.2-63%, Al2O3 18.6-19.1%, Na2O 4.997-5.358%, K2O 2.2-2.4%, MgO 1.78-1.79%, Li2O 4.6-4.94%, CaO 0.2%, ZrO2 2.5-2.54%, TiO2 0.002-0.004%, Y2O3 1.17-1.9%, ZnO 0-0.4%, MoO3 0-0.01%, P2O5 0-0.05% and additives 0.05-0.12%. The additives are at least one of WO3, La2O3 and Ga2O3. The molar ratio of R2O to Al2O3 is greater than 1, R is Li, Na or K. The molar ratio of Li2O to Al2O3 is less than 1. The mass ratio of Y2O3 to ZrO2 is less than 1. XO is less than 2%, and X is Ca or Mg. The application solves the problems of poor ball drop resistance and low ion exchange efficiency of the lithium-aluminum-silicon glass.

Description

Technical Field

[0001] This invention relates to the field of glass technology, specifically to lithium aluminum silicon glass with high resistance to falling balls and its processing technology. Background Technology

[0002] Lithium aluminosilicate glass (Li2O-Al2O3-SiO2 system, abbreviated as LAS glass) is a functional glass material with lithium (Li), aluminum (Al), and silicon (Si) as its main components. Due to its excellent physicochemical properties, such as high strength, low coefficient of thermal expansion, high transmittance, and chemical stability, lithium aluminosilicate glass has been widely used in electronic displays, optical devices, high-temperature resistant materials, aerospace, construction, automobiles, and other fields.

[0003] There are certain differences in the development of lithium aluminum silicon glass between domestic and international markets. The market is mainly dominated by Corning's overflow process and Asahi Glass's float process, but these methods also present some problems: the overflow process is expensive and requires extremely high precision in process control; the float process, due to differences in glass formulations, results in significant performance variations. The float process for lithium aluminum silicon glass has a narrow range of component control and significant differences in drop ball resistance. For example, the drop ball resistance of existing 0.55mm thick lithium aluminum silicon glass is generally around 0.2J, which is insufficient to meet the application requirements of modern electronic products. Furthermore, the popular glass tempering processes on the market mainly use water-soaked salt and mixed salt methods, and the ion exchange process is inefficient and has poor tempering effects, also leading to poor drop ball performance.

[0004] With the rapid development of the consumer electronics and automotive display industries, given the poor drop ball performance of existing lithium aluminum silicon glass, there is an urgent need to develop a high-performance lithium aluminum silicon glass with high drop ball resistance and better tempering effect, as well as its processing technology. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide lithium aluminum silicon glass with high resistance to falling balls and its processing technology, thereby solving the problems of poor resistance to falling balls, low ion exchange efficiency and poor tempering effect of lithium aluminum silicon glass.

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

[0007] On one hand, the present invention provides a lithium aluminum silicon glass with high resistance to falling balls, comprising the following components by mass percentage: SiO2 62.2-63%, Al2O3 18.6-19.1%, Na2O 4.997-5.358%, K2O 2.2-2.4%, MgO 1.78-1.79%, Li2O 4.6-4.94%, CaO 0.2%, ZrO2 2.5-2.54%, TiO2 0.002-0.004%, Y2O3 1.17-1.9%, ZnO 0-0.4%, MoO3 0-0.01%, P2O5 0-0.05%, additives 0.05-0.12%; wherein, the additives are one or more of WO3, La2O3 and Ga2O3; n(R2O) / n(Al2O3)>1, where R is Li, Na and K; and the molar ratio of Li2O to Al2O3 n(Li2O) / n(Al2O3)<1; the mass ratio of Y2O3 to ZrO2 m(Y2O3) / m(ZrO2)<1; the mass percentage of XO<2%, where X is Ca and Mg.

[0008] Preferably, the thickness of the lithium aluminum silicon glass is 0.33-1.5 mm.

[0009] In this invention, SiO2, as a network forger, constitutes the framework of the glass and is fundamental to providing chemical stability and mechanical strength. If the content is too high, the glass melting temperature is too high, the viscosity is high, which is detrimental to ion exchange; if the content is too low, the glass network is incomplete, and chemical stability and strength decrease. Therefore, in the lithium aluminum silicon glass of this invention, the SiO2 content accounts for 62.2-63%. Al2O3, as a network intermediate / forger, is the core engine of chemical strengthening. It can form [AlO4] tetrahedra, strengthen the network, and create ion exchange sites. Its content directly determines the depth of ion exchange (DOL).

[0010] This invention specifies that the molar ratio of R2O to Al2O3, n(R2O) / n(Al2O3) > 1, where R is Li, Na, or K, and n(Li2O) / n(Al2O3) < 1. Each [AlO4] tetrahedron carries a negative charge, requiring a positively charged alkali metal cation nearby to balance the charge. This structure creates perfect "sites" for subsequent ion exchange. During chemical fortification, Na in the molten salt... + and K + It can come in and replace the Li at this site. + From a thermodynamic point of view, Li + Due to its smallest ionic radius and highest electric field strength, it preferentially occupies the charge balance sites next to [AlO4]. n(Li2O) / n(Al2O3) < 1, meaning there is enough aluminum oxide to "consume" all the Li. + Let every Li+ Both act as charge balancers for [AlO4]. In this case, almost all Li present in the network... + Both are related to [AlO4] - Closely related, these Li + It has relatively strong migration ability in the network and can be transferred to Na+ in molten salt during chemical reinforcement. + and K + Effective displacement occurs. When n(Li₂O) / n(Al₂O₃) > 1, excess Li₂ is released. + This breaks silicon-oxygen bonds, forming non-bridging oxygen, which disrupts the continuity and openness of the network. Those Li-type network modifiers... + Their energy environment and Li, as a charge balancer + Unlike other networks, these networks are more randomly distributed in the gaps between networks, and they need to overcome higher energy barriers when migrating, resulting in lower migration efficiency.

[0011] In this invention, the mass percentage of XO is limited to <2%, where X represents Ca or Mg. CaO and MgO severely interfere with the chemical strengthening process of lithium aluminum silicon glass and damage its microstructure, thereby degrading the performance of the final product. 2+ and Mg 2+ These are divalent alkaline earth metal ions, carrying two positive charges. In the glass network structure, their binding ability with oxygen ions is far stronger than that of monovalent Li ions. + These divalent ions anchor themselves at specific locations within the glass network, hindering the overall migration of ions within the network. When Li... + When attempting to diffuse outwards, Na + When attempting inward diffusion for ion exchange, these fixed divalent ions act as roadblocks, significantly reducing the exchange rate and diffusion depth. The driving force behind chemical strengthening is the "adaptability" of the glass network to ion size. Using larger ions like Na... + Replace smaller ionic Li + This will generate compressive stress on the surface. 2+ Mg 2+ Ionic radius and Na + Similarly, if these similarly sized ions already exist in the glass network, they will occupy structural sites, weakening the network's ability to introduce larger Na+ ions. + The resulting strain sensing capability leads to a low final surface compressive stress CS.

[0012] In this invention, the mass ratio of Y₂O₃ to ZrO₂ is limited to <1. ZrO₂ has an extremely high electric field strength, greatly improving the fracture toughness and hardness of the glass; however, excessive amounts can cause the glass to easily crystallize during forming and strengthening, making it opaque and brittle. Therefore, its proportion must be strictly controlled. The Y₂O₃ contains Y₂O₃.3+ With a large radius and high electric field strength, similar to ZrO2, Y2O3 can improve the elastic modulus and hardness of glass. It can suppress the tendency of glass to crystallize, especially when the ZrO2 content is high, Y2O3 can play a stabilizing role.

[0013] Preferably, when MgO and CaO are added simultaneously, the mass percentage of Mg is greater than the mass percentage of Ca.

[0014] On the other hand, the present invention provides a processing method for the above-mentioned high-strength, drop-ball-resistant lithium aluminum silicon glass, comprising the following steps:

[0015] S1: After glass production, ink is sprayed onto the glass surface before CNC cutting. This operation, performed before CNC cutting, protects the glass surface from damage during processing.

[0016] S2: Select a suitable cutting head to cut the glass after it has been coated with ink;

[0017] S3: The cut glass is finely carved and ground. This step involves chamfering the edges of the glass to obtain the desired glass shape.

[0018] S4: Perform an edge-sweeping process on the finely carved and ground glass. This step is to refine the edges of the finely carved and ground glass and remove edge defects caused during the grinding process.

[0019] S5: Remove ink from the swept glass, then polish and clean it to remove tiny cracks on the glass surface.

[0020] S6: After the cleaned glass undergoes a full visual inspection, defective products with scratches or abrasions caused by the processing are removed, thus obtaining qualified glass samples before tempering.

[0021] S7: The glass sample is strengthened by first strengthening with pure sodium nitrate, and then strengthening it a second time in a tempering furnace with a sodium brushing tank and a potassium salt tank. Both the sodium brushing tank and the potassium salt tank contain pure potassium nitrate. After the first strengthening, the sample is first placed in the sodium brushing tank for sodium brushing treatment at a temperature of 415-425℃ for 3-5 minutes, with salt dripping for 1-2 minutes. After the sodium brushing treatment, the sample is then placed in the potassium salt tank for secondary strengthening.

[0022] In this invention, when strengthening glass, a sodium brushing treatment is performed between the primary and secondary strengthening processes. This removes sodium salts remaining on the glass surface from the primary strengthening, significantly shortening the overall strengthening time. It also initiates a preliminary potassium-sodium exchange on the glass surface, improving its suitability for the secondary strengthening process. The secondary strengthening primarily involves a deeper potassium-sodium exchange.

[0023] Preferably, in step S3, the processing parameters for fine carving and grinding are as follows: 450-grit abrasive is used for chamfering and roughing, and 1200-grit abrasive is used for finishing. The spindle speed for chamfering is 38000±2000 rpm, and the feed rate is 260-300 mm / min; the spindle speed for roughing is 38000±2000 rpm, and the feed rate is 800-1000 mm / min; the spindle speed for finishing is 38000±2000 rpm, and the feed rate is 600-800 mm / min.

[0024] Preferably, in step S4, the processing parameters for the edge-sweeping process are as follows: processing time 40-60 min, short side speed 0.2-0.25 mm / min, long side speed 0.2-0.25 mm / min, and arc rotation speed 1000-1200 rpm; the brush wheel is made of a mixture of pure pig hair and pig hair abrasive, with a powder concentration of 1.15 ± 0.05 g / cm³. 3 The removal amount is 0.01-0.03mm.

[0025] Preferably, in step S7, the primary enhanced ion exchange is lithium-sodium exchange, the primary enhanced temperature is 380-460℃, the exchange time is 1.5-5h, and a compressive stress layer is formed.

[0026] Preferably, in step S7, the secondary enhanced ion exchange is potassium-sodium exchange, the secondary enhanced temperature is 400-450℃, and the exchange time is 1-3h.

[0027] Preferably, in step S7, before the primary strengthening and sodium brushing treatment, the glass is preheated to 360-390℃ and held for 8-10 minutes.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] The high-strength, drop-ball-resistant lithium aluminum silicon glass and its processing technology described in this invention effectively solve the technical pain points of existing lithium aluminum silicon glass, such as poor drop-ball resistance, low ion exchange efficiency, and unsatisfactory tempering effect, through precise design of glass component proportions and innovative optimization of processing technology.

[0030] 1. This invention optimizes the microstructure of lithium aluminum silicon glass by strictly controlling the component ratio and introducing WO3, La2O3, and Ga2O3 additives. Combined with an innovative secondary strengthening process (first-stage lithium-sodium exchange + sodium brushing + second-stage potassium-sodium exchange), the five-point drop ball fracture impact energy of 0.55mm thick lithium aluminum silicon glass far exceeds the 0.2J level of existing technologies, with a fracture height of 35-65cm and a surface compressive stress (CS) increased to 1162-1194MPa. This significantly enhances the glass's impact resistance and fully meets the stringent requirements for drop ball resistance in consumer electronics, automotive displays, and other fields.

[0031] 2. This invention adjusts the ratio of Al₂O₃ to alkali metal oxides to allow Li₂O₃ to form a more homogeneous mixture. + It effectively acts as a charge balancer for the [AlO4] tetrahedron, creating abundant and efficient sites for ion exchange and avoiding excessive Li. + This addresses the issue of disrupting the continuity of the glass network. Simultaneously, strictly limiting the content of divalent alkaline earth metal oxides such as CaO and MgO eliminates their "roadblock" effect on ion migration, significantly improving the ion exchange rate and diffusion depth (DOL can reach 4.734-4.869 μm). Furthermore, the additional sodium brushing treatment after the first strengthening not only removes residual sodium salts from the glass surface but also completes preliminary potassium-sodium exchange ahead of time, laying the foundation for secondary strengthening and further optimizing the tempering effect, resulting in a more uniform distribution of compressive stress on the glass surface and internal stress.

[0032] 3. In this invention, the addition of ZrO2 significantly improves the fracture toughness and hardness of the glass, while Y2O3 effectively suppresses the tendency of ZrO2 to crystallize. The synergistic effect of these two components ensures the transparency and mechanical properties of the glass. The appropriate ratio of SiO2 and Al2O3 constructs a stable glass network framework, ensuring the chemical stability and mechanical strength of the glass. Testing shows that the four-point bending strength (4PB) of the glass of this invention reaches 1025-1060 MPa, and the central tension (CT) is controlled at 10.339-10.462 MPa, demonstrating excellent overall mechanical properties. Simultaneously, the optimized parameters of processing steps such as fine carving, grinding, edge sweeping, and polishing reduce edge defects and surface microcracks during glass processing, further improving the structural integrity and reliability of the glass.

[0033] 4. The glass formulation of this invention is adapted to the float glass production process, significantly reducing the cost of production equipment and process control compared to Corning's overflow process. The pure sodium nitrate and pure potassium nitrate strengthening system used in the processing replaces the traditional water-soaking salt and mixed salt processes, simplifying the operation process. Furthermore, the sodium brushing treatment shortens the overall strengthening time and improves production efficiency. In addition, the formulation has a wide range of component ratios, and the processing parameters are adjustable, allowing for flexible adjustments based on the needs of different application scenarios. This facilitates large-scale mass production and possesses high market promotion value. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0035] Examples 1-6

[0036] The formulations of the high-strength, drop-ball-resistant lithium aluminum silicon glass used in Examples 1-6 are shown in Table 1:

[0037] Table 1. Formulations of high-strength, drop-ball-resistant lithium aluminosilicate glass in Examples 1-6

[0038]

[0039] The processing technology for the 0.55mm thick lithium aluminum silicon glass of Examples 1-6 is as follows:

[0040] S1: After glass production, ink is sprayed onto the glass surface before CNC cutting.

[0041] S2: Cut the glass after spraying the ink;

[0042] S3: The cut glass is then finely polished. 450-grit abrasive is used for chamfering and roughing, while 1200-grit abrasive is used for finishing. The spindle speed for chamfering is 38,000 rpm with a feed rate of 280 mm / min; the spindle speed for roughing is 38,000 rpm with a feed rate of 900 mm / min; and the spindle speed for finishing is 38,000 rpm with a feed rate of 700 mm / min.

[0043] S4: Perform edge-sweeping processing on the finely carved and ground glass. Processing time: 50 minutes. Short side speed: 0.25 mm / min. Long side speed: 0.25 mm / min. Arc rotation speed: 1100 rpm. The abrasive wheel is made of a mixture of pure pig bristles and pig bristle abrasive skin, with an abrasive powder concentration of 1.15 g / cm³. 3 The amount removed was 0.015 mm.

[0044] S5: Remove ink from the swept glass, then polish and clean it;

[0045] S6: After the cleaned glass undergoes a full visual inspection, defective products such as scratches and abrasions caused during the processing are removed, thus obtaining qualified glass samples before tempering.

[0046] S7: The glass sample was strengthened by first raising the temperature from room temperature to 390°C and holding it there for 10 minutes. Then, it underwent a first strengthening process in a tempering furnace with a sodium salt bath containing pure sodium nitrate at a temperature of 435°C for 2.5 hours. After exiting the furnace, the glass was slowly cooled from 390°C to 180°C in a preheating furnace, then removed and cooled to room temperature. The cooled glass was then placed back into the preheating furnace and raised from room temperature to 390°C, held there for 10 minutes, and then placed into a tempering furnace with sodium brushing and potassium salt baths containing pure potassium nitrate. Sodium brushing was performed first in the sodium brushing bath at a temperature of 425°C for 3 minutes, followed by salt dripping for 2 minutes. Then, the glass underwent a second strengthening process in the potassium salt bath at a temperature of 405°C for 1 hour. After the second strengthening, the glass was transferred to the preheating furnace and slowly cooled from 390°C to 180°C, then removed and cooled to room temperature for cleaning.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that in the processing of lithium aluminum silicon glass, step S7 is as follows: First, the glass is heated from room temperature to 390°C and held at that temperature for 10 minutes. Then, it is subjected to a first strengthening in a tempering furnace with a sodium salt bath containing pure sodium nitrate. The first strengthening temperature is 435°C and the time is 150 minutes. After exiting the furnace, the glass is slowly cooled from 390°C to 180°C in a preheating furnace. Then, it is taken out and cooled to room temperature. The cooled glass is then put into the preheating furnace and heated from room temperature to 390°C, held at that temperature for 10 minutes. Then, it is placed into a tempering furnace with a potassium salt bath for a second strengthening. The potassium salt bath contains pure potassium nitrate. The second strengthening temperature is 405°C and the time is 55 minutes. After the second strengthening, the glass is transferred to the preheating furnace and slowly cooled from 390°C to 180°C. Then, it is taken out, cooled to room temperature, and cleaned.

[0049] Comparative Example 2

[0050] The difference from Example 1 is that step S4 is not performed in the processing of lithium aluminum silicon glass.

[0051] Comparative Example 3

[0052] The difference from Example 1 is that, in the processing of lithium aluminum silicon glass, polishing is not performed in step S5.

[0053] Comparative Example 4

[0054] The difference from Example 1 is that in the processing of lithium aluminum silicon glass, step S7: first, the glass is heated from room temperature to 390°C and kept at that temperature for 10 minutes. Then, it is strengthened once in a tempering furnace with a sodium salt bath. The sodium salt bath contains pure sodium nitrate. The temperature of the first strengthening is 435°C and the time is 150 minutes. After the first strengthening, the glass is transferred to a preheating furnace and slowly cooled from 390°C to 180°C. Then, it is taken out, cooled to room temperature, and cleaned.

[0055] Comparative Example 5

[0056] The difference from Example 1 is that in the processing technology of lithium aluminum silicon glass, the strengthening time in step S7 is extended to 70 minutes.

[0057] Comparative Examples 6-9

[0058] The formulations of lithium aluminum silicon glass for comparative examples 6-9 are shown in Table 2.

[0059] Table 2 Formulations of lithium aluminum silicon glass in Comparative Examples 6-9

[0060]

[0061] The processing technology of lithium aluminum silicon glass in Comparative Examples 6-9 is the same as that in Examples 1-6.

[0062] Performance tests were conducted on the processed lithium aluminum silicon glass of Examples 1-6 and Comparative Examples 1-9:

[0063] (1) A 4PB test was performed using a universal testing machine. During sample preparation, the glass was cut into strips approximately 50mm long, 15mm wide, and 5mm thick. The calculation formula is as follows:

[0064] P=3FL / 2bh 2 ;

[0065] In the formula, P: flexural strength, MPa; F: load, N; L: span of support, mm; b: specimen width, mm; h: specimen thickness, mm.

[0066] (2) The values ​​of CS, DOL and CT were determined using FSM-6000 and SLP-2000 instruments: When testing the above data, the refractive index and photoelastic coefficient of the glass were 1.528nm / cm / MPa and 28.5nm / cm / MPa when using a wavelength of 520nm; and the refractive index and photoelastic coefficient of the glass were 1.52nm / cm / MPa and 27.9nm / cm / MPa when using a wavelength of 590nm.

[0067] (3) Drop ball test: The test is conducted using a drop ball tester. The glass is fixed horizontally on the drop ball mold, and the ball is released through an electromagnetic device. The ball falls freely and impacts the center or edge of the glass at a specified position. The test is conducted every 5cm. The weight of the ball is 64g. The test is conducted 3 times at each height and each point to determine the drop height.

[0068] The test results are shown in Table 3-4:

[0069] Table 3 Performance test results of lithium aluminum silicon glass in Examples 1-6

[0070]

[0071] Table 4 Performance test results of lithium aluminum silicon glass in Comparative Examples 1-9

[0072]

[0073] As shown in Tables 3-4, Comparative Example 1, employing the traditional water-soaking salt process, experiences a decrease in potassium-sodium exchange efficiency during the second-strength stage, leading to a decrease in CS and DOL, an increase in central tensile stress, and a decline in impact resistance. Comparative Examples 2 and 3, lacking edge-sweeping and polishing processes respectively, result in defects such as fine cracks and edge chipping in the glass. When a steel ball impacts the glass, tensile stress is more easily amplified from these defects, causing the glass to shatter. Comparative Example 4, using a first-strength process, cannot achieve high CS, resulting in low surface compressive stress and weak impact resistance. Comparative Example 5 extends the first-strength tempering time, and CS follows a parabolic curve with increasing exchange time, decreasing CS, reducing surface pressure, and weakening impact resistance. In Comparative Example 6, due to the near-1 molar ratio of Li2O to Al2O3 and a high fixed lithium content, the glass exhibits greater and deeper stress and stress layer depth during lithium-sodium and potassium-sodium exchange, resulting in greater impact resistance. However, this increases production costs. Considering the high cost-effectiveness of lithium carbonate, actual production will strive to maintain the above ratios. Comparative Example 7 is the opposite of Comparative Example 6; the amount of lithium ions used for exchange is small, resulting in a decrease in both CS and DOL, and a significant reduction in impact resistance. In Comparative Example 8, the increased proportion of Y2O3 reduces the hardness of the glass. Compared to Comparative Example 9, the addition of an appropriate amount of La2O3 in Example 1, while acting as a flux, can improve the mechanical strength and hardness of the glass, and enhance its impact resistance.

[0074] As can be seen from the above examples and comparative examples, the design of the proportions of lithium aluminum silicon glass and the parameter control of the processing and strengthening process have a significant impact on the drop ball performance of the glass. This invention, through the rational design of the proportions of Al2O3, Na2O, Li2O, and K2O, while strictly controlling the content of CaO and MgO, enhances the ion exchange capacity. Simultaneously, through a specific glass processing flow, the negative effects of glass processing and surface defects on drop ball performance are reduced. The resulting lithium aluminum silicon glass, after secondary strengthening, exhibits high impact resistance and has broad application prospects.

Claims

1. A lithium aluminum silicon glass with high resistance to falling balls, characterized in that, The composition includes the following components by mass percentage: SiO2 62.2-63%, Al2O3 18.6-19.1%, Na2O 4.997-5.358%, K2O 2.2-2.4%, MgO 1.78-1.79%, Li2O 4.6-4.94%, CaO 0.2%, ZrO2 2.5-2.54%, TiO2 0.002-0.004%, Y2O3 1.17-1.9%, ZnO 0-0.4%, MoO3 0-0.01%, P2O5 0-0.05%, additives 0.05-0.12%; wherein, the additives are one or more of WO3, La2O3 and Ga2O3; n(R2O) / n(Al2O3)>1, R is Li, Na and K; and n(Li2O) / n(Al2O3)<1; m(Y2O3) / m(ZrO2)<1; XO mass percentage<2%, X is Ca and Mg.

2. The lithium aluminum silicon glass with high resistance to falling balls as described in claim 1, characterized in that, When MgO and CaO are added simultaneously, the mass percentage of Mg is greater than the mass percentage of Ca.

3. The processing technology for high-strength lithium aluminum silicon glass with high resistance to falling balls as described in claim 1 or 2, characterized in that, Includes the following steps: S1: After glass production, ink is sprayed onto the glass surface before CNC cutting. S2: Cut the glass after spraying the ink; S3: Fine carving and grinding of the cut glass; S4: Perform an edge-sweeping process on the finely carved and ground glass; S5: Remove ink from the swept glass, then polish and clean it; S6: After the cleaned glass undergoes a full visual inspection, defective products caused during the processing are removed, thus obtaining qualified glass samples before tempering. S7: The glass sample is strengthened by first strengthening with pure sodium nitrate, and then strengthening it a second time in a tempering furnace with a sodium brushing tank and a potassium salt tank. Both the sodium brushing tank and the potassium salt tank contain pure potassium nitrate. After the first strengthening, the sample is first placed in the sodium brushing tank for sodium brushing treatment at a temperature of 415-425℃ for 3-5 minutes, with salt dripping for 1-2 minutes. After the sodium brushing treatment, the sample is then placed in the potassium salt tank for secondary strengthening.

4. The processing technology for high-strength lithium aluminum silicon glass with high resistance to falling balls as described in claim 3, characterized in that, In step S3, the machining parameters for fine carving and grinding are as follows: 450-grit abrasive is used for chamfering and roughing, and 1200-grit abrasive is used for finishing. The spindle speed for chamfering is 38000±2000 rpm, and the feed rate is 260-300 mm / min; the spindle speed for roughing is 38000±2000 rpm, and the feed rate is 800-1000 mm / min; the spindle speed for finishing is 38000±2000 rpm, and the feed rate is 600-800 mm / min.

5. The processing technology of the high-strength, drop-ball-resistant lithium aluminum silicon glass as described in claim 3, characterized in that, In step S4, the processing parameters for the edge-sweeping process are as follows: processing time 40-60 min, short side speed 0.2-0.25 mm / min, long side speed 0.2-0.25 mm / min, and arc rotation speed 1000-1200 rpm; the brush wheel is made of a mixture of pure pig hair and pig hair abrasive, with a powder concentration of 1.15 ± 0.05 g / cm³. 3 The removal amount is 0.01-0.03mm.

6. The processing technology of the high-strength, drop-ball-resistant lithium aluminum silicon glass as described in claim 3, characterized in that, In step S7, the temperature for one strengthening is 380-460℃, and the time is 1.5-5h.

7. The processing technology for high-strength lithium aluminum silicon glass with high resistance to falling balls as described in claim 3, characterized in that, In step S7, the temperature for secondary strengthening is 400-450℃, and the time is 1-3 hours.

8. The processing technology of the high-strength, drop-ball-resistant lithium aluminum silicon glass as described in claim 3, characterized in that, In step S7, before the first strengthening and sodium brushing treatment, the glass is preheated to 360-390℃ and held for 8-10 minutes.

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