High-strength stability engineering stress distribution glass and preparation method thereof

Abstract

The invention provides high-strength stability engineering stress distribution glass and a preparation method thereof, the glass is prepared by adopting a secondary ion exchange method, the glass comprises an ion separation layer, and the ion separation layer is positioned in a primary ion exchange layer of the glass. According to the invention, the ion separation layer is arranged to cut off a glass ion exchange path, so that during secondary ion exchange, primary ion exchange ions above the ion separation layer can be fully exchanged, and the concentration of primary ion exchange ions below the ion separation layer is kept stable. Due to the characteristic, the secondary ion exchange process of the glass is simpler, more convenient and controllable, the problem of excessive ion exchange is effectively avoided, the glass still has a better primary ion exchange pressure stress effect, and the strength stability of the glass is improved while the strength of the glass is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass preparation, and particularly relates to a high-strength and stable engineering stress distribution glass and a preparation method thereof. Background Art

[0002] Glass is widely used in many fields due to its excellent properties. The structure of glass is mainly composed of Si-O covalent bonds, showing typical brittle mechanical behavior. In theory, the fracture strength of glass calculated based on the chemical bond strength can reach 7000 MPa. However, in practical applications, the strength of glass is often difficult to exceed 100 MPa, far lower than the theoretical value. The main reason for this problem is that glass is extremely sensitive to surface damage, and microcracks and damage on the surface are inevitable during actual processing and use. When stressed, stress concentration occurs at the crack, leading to rapid crack propagation and significantly reducing the actual strength of the glass.

[0003] To solve this problem, researchers have developed ion exchange strengthening technology to enhance glass. This technology places the glass in a high-temperature nitrate molten salt, and at a certain temperature, alkali metal ions (such as Na + ) in the glass are exchanged with larger alkali metal ions (such as K + ) in the molten salt. After the exchange is completed, the larger ions form a squeezing effect on the glass surface, generating a layer of compressive stress, thereby inhibiting the propagation of surface microcracks and significantly improving the strength of the glass. However, the high-temperature molten salt has a certain corrosiveness to the glass surface, which may lead to an increase in the number of microcracks and damage the glass strength. These two conflicting effects result in a decrease in the reliability of ion-exchanged glass, that is, although the strength of the strengthened glass is increased, the strength dispersion also becomes larger. The strength of each piece of strengthened glass in the same batch is different, and the gap between the highest value and the lowest value is relatively large, bringing many inconveniences to process design and engineering applications.

[0004] To overcome the above problems, researchers have further developed a secondary ion exchange method. This method performs a secondary treatment on the glass that has undergone primary ion exchange, and uses a molten salt containing alkali metal ions with a smaller ionic radius (such as Na + ) to perform a short-time exchange again to partially release the surface compressive stress, so that the maximum value of the compressive stress migrates to a certain depth below the surface, thereby avoiding the influence of surface microcracks. Although this process will cause a slight decrease in the highest strength of the glass, the compressive stress layer is no longer directly affected by surface microcracks, the sensitivity of the glass strength to the crack morphology is significantly reduced, and the strength dispersion is also greatly reduced (2% - 5%). The strength of the glass in the same batch tends to be consistent, and the reliability of engineering applications is significantly improved. Since this effect is achieved by designing the stress distribution, this technology is called engineering stress distribution glass treatment technology.

[0005] However, the commonly used secondary ion exchange method at present is to immerse the whole glass in molten salt for treatment. During this process, the ions in the glass and the ions in the molten salt are both in an open state of mutual diffusion, making it difficult to control the quantity and degree of secondary ion exchange. If the exchange time is too short, the ion exchange process is slow, the exchange depth is insufficient, and the effect of stress layer inward migration cannot be achieved; if the exchange time is too long, not only does the primary ion exchange layer exchange ions with the ions in the molten salt, but also it diffuses into the glass interior, resulting in a decrease in the ion concentration of the primary ion exchange layer, a significant drop in the compressive stress, and the loss of the ion strengthening effect. In the traditional process, by strictly controlling the temperature and time of secondary exchange to adjust the degree and depth of surface compressive stress removal, but this process is greatly affected by equipment and environmental conditions, the control is relatively complex, and it is difficult to ensure the treatment effect of engineering stress distribution. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a high-strength and stable engineering stress distribution glass and a preparation method thereof, making the secondary ion exchange process of the glass simpler and more controllable, and achieving the improvement of glass strength while enhancing the glass strength stability.

[0007] To achieve the above object, the present invention provides the following technical solution: A high-strength and stable engineering stress distribution glass is prepared by the secondary ion exchange method, and the glass includes an ion isolation layer, and the ion isolation layer is located inside the primary ion exchange layer of the glass.

[0008] Furthermore, the thickness of the ion isolation layer is 100 μm - 500 μm, and the boundary of the ion isolation layer is 2 mm - 3 mm away from the glass boundary.

[0009] Furthermore, the ion isolation layer is below the glass surface and 50 μm - 150 μm higher than the deepest part of the primary ion exchange layer.

[0010] Furthermore, the deepest part of the primary ion exchange layer is detected by EDS or EPMA.

[0011] Furthermore, the ion isolation layer is prepared by the laser internal engraving method, the wavelength of the laser is 355 nm - 532 nm, the laser spot diameter is 10 μm - 90 μm, the laser power is 5 W - 30 W, the pulse frequency is 20 kHz - 50 kHz, and the scanning speed is 2 mm / s - 50 mm / s.

[0012] The present invention also provides a preparation method of a high-strength and stable engineering stress distribution glass, and the specific steps are as follows: Perform primary ion exchange on the glass sample to be strengthened: Use the laser internal engraving method to prepare an ion isolation layer inside the primary ion exchange layer of the glass; The secondary ion exchange is carried out on the glass sample with an ion isolation layer to obtain a glass with a high-strength and stable engineering stress distribution.

[0013] In a further preparation method, the ion isolation layer is below the glass surface and 50 μm to 150 μm higher than the deepest part of the primary ion exchange layer. The thickness of the ion isolation layer is 100 μm to 500 μm, and the boundary of the ion isolation layer is 2 mm to 3 mm away from the glass boundary.

[0014] In a further preparation method, the ion isolation layer is prepared by the method of internal laser engraving. The wavelength of the laser is 355 nm to 532 nm, the diameter of the laser spot is 10 μm to 90 μm, the laser power is 5 W to 30 W, the pulse frequency is 20 kHz to 50 kHz, and the scanning speed is 2 mm / s to 50 mm / s.

[0015] In a further preparation method, the primary ion exchange temperature is 100 °C to 120 °C lower than the glass transition temperature, and the time of primary ion exchange is 10 h to 60 h.

[0016] In a further preparation method, the molten salt used for the secondary ion exchange is a mixed salt of KNO3 and NaNO3. The proportion of KNO3 in the mixed salt is 35% to 65%, and the total amount of the mixed salt is 100%. During the secondary ion exchange, the internal ion exchange temperature of the glass is 40 °C to 60 °C lower than the primary ion exchange temperature, and the time of secondary ion exchange is 15 min to 45 min.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a glass with a high-strength and stable engineering stress distribution. The setting of the ion isolation layer truncates the glass ion exchange path, so that during the secondary ion exchange, the primary ion exchange ions above the ion isolation layer can be fully exchanged, while the concentration of the primary ion exchange ions below the ion isolation layer remains stable. This characteristic effectively avoids the problem of over-ion exchange, ensures that the glass still has a good primary ion exchange compressive stress effect, thereby significantly improving the glass strength while ensuring the strength stability. Since the ion isolation layer can precisely control the ion exchange process, the fracture strength of the glass is significantly improved, reaching 450 MPa to 650 MPa. At the same time, the hardness is also significantly increased, and the microhardness can reach 700 kg / mm². In addition, the sensitivity of the glass to surface defects is reduced, and the strength stability is good, and the Weibull modulus can reach 72. The improvement of these properties enables the glass to withstand greater external forces in practical applications, reduces the fracture risk caused by surface defects, and improves the reliability and service life of the glass.

[0018] Preferably, by adjusting the parameters of laser internal engraving, such as the wavelength, spot diameter, power, pulse frequency, and scanning speed of the laser, the position of the ion isolation layer can be easily adjusted, thereby effectively controlling the depth of the ion exchange layer. This provides great convenience for preparing ESP engineering stress distribution glass with different parameter requirements, meeting the diverse demands for glass performance in different application scenarios.

[0019] Preferably, the presence of the ion isolation layer changes the stress distribution state inside the glass. It forms a more reasonable stress gradient in the thickness direction of the glass, avoiding the occurrence of stress concentration. This optimized stress distribution further improves the impact resistance and bending resistance of the glass, enabling the glass to disperse stress more evenly when subjected to external forces, thereby enhancing the overall strength and stability of the glass.

[0020] The present invention also provides a method for preparing high-strength and stable engineering stress distribution glass. This method applies laser internal engraving technology to the glass preparation process to prepare an ion isolation layer inside the primary ion exchange layer of the glass, making the secondary ion exchange process simpler and more controllable. Compared with traditional processes, it requires no complex operations and equipment, reducing the preparation difficulty and cost. At the same time, through clear settings of primary ion exchange and secondary ion exchange parameters, such as temperature, time, and molten salt ratio, etc., the stability and repeatability of the preparation process are further ensured.

[0021] Preferably, as a non-contact processing technology, laser internal engraving will not cause mechanical damage to the material surface when preparing the ion isolation layer, nor will it generate microcracks on the new internal surface. This ensures the integrity and strength of the glass, avoiding the adverse effects of defects introduced by processing on the glass performance. Therefore, the glass prepared by this method has a higher fracture strength while still maintaining high strength stability, further enhancing the practicality and reliability of the engineering stress distribution glass.

[0022] Preferably, this method has a high degree of flexibility. By adjusting the laser internal engraving parameters and ion exchange parameters, ESP engineering stress distribution glass with different parameter requirements can be prepared. This enables the method to meet the specific requirements for glass performance in different engineering fields, providing strong support for the application of glass in multiple fields such as aerospace, construction, and electronics. At the same time, the large-scale production feasibility of this method is high, and it is expected to promote the wide application of high-strength and stable engineering stress distribution glass. Description of the Drawings

[0023] Figure 1 It is the thermal analysis result of the glass in Example 1 of the present invention; Figure 2 It is the Na / K ion distribution result of the glass in Example 1 of the present invention after primary ion exchange, showing the depth of primary ion exchange; Figure 3 Schematic diagram of laser internal engraving for processing the ion separation layer in Embodiment 1 of the present invention; Figure 4 Schematic diagram of the ion distribution in the glass after secondary ion exchange in Embodiment 1 of the present invention; Figure 5 Microhardness test results of the glass after primary and secondary ion exchanges in Embodiment 1 of the present invention. The compressive stress generated by the primary ion exchange effectively inhibits the propagation of surface cracks in the glass. After the secondary exchange, the maximum compressive stress layer of the glass moves to the subsurface of the glass, the surface compressive stress is small, and its inhibitory effect on surface cracks is also small, resulting in a certain crack propagation. However, its maximum strain is at the subsurface of the glass, so when the elastic potential energy stored in the indentation area is released, the glass around the indentation ruptures; Figure 6 Macrophotograph of the fracture of the glass specimen after three-point bending test of the glass after primary and secondary ion exchanges in Embodiment 1 of the present invention. The original glass shows obvious brittle fracture. The strengthening effect of the glass after primary ion exchange is obvious, and the fracture surface shows pulverulent damage. Cracks propagate throughout the fracture surface of the glass after secondary ion exchange, and the difference between the tensile surface and the compressive surface during loading is obvious. The fracture surface of the compressive surface is relatively flat, while the fracture surface of the tensile surface is uneven and shows a large number of cracks. Specific Embodiments

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] The present invention provides a method for preparing a high-strength and stable engineering stress distribution glass, which improves the method of secondary ion exchange treatment of the glass, realizes the strengthening of SiO2 glass, the fracture strength of the strengthened glass is increased, the hardness is increased, the sensitivity to surface defects is low, and the strength stability is good. The specific steps are as follows: S1: Perform differential scanning calorimetry on the glass sample to be strengthened to determine the glass transition temperature Tg of the glass sample. Cut the glass sample into the required size, polish and chamfer it, and then heat the glass sample specimen to a temperature 20°C lower than the Tg temperature to anneal and eliminate residual stress; S2: Add KNO3 to the crucible and heat it to a temperature 100°C - 120°C lower than the Tg temperature of the glass sample to melt KNO3. Place the glass sample in the molten KNO3 and keep it warm for 10h - 60h for primary ion exchange. After completion, take out the glass sample and cool it to room temperature, and clean the surface; S3: Using laser inner engraving technology, the laser beam of the laser inner engraving machine is shaped to control the focal position and depth of the laser beam, and the internal ion isolation layer is processed below the glass surface at a position 50μm~150μm higher than the thickness of the primary ion exchange layer to isolate the primary ion exchange layer, where the thickness of the primary ion exchange layer is detected by EDS (energy spectrum analysis) or EPMA (electron probe); S4: Add the mixed salt of KNO3 and NaNO3 into the crucible and heat it to completely melt the mixed salt. Immerse the laser engraved glass in the molten salt and perform secondary ion exchange for 15min~45min. After completion, take out the glass sample and cool it to room temperature, and clean the surface to obtain engineering stress distribution glass with high strength and stability.

[0026] Preferably, in S3, since the purpose of laser engraving is to retain the compressive stress formed by the primary ion exchange, the depth of laser engraving should be shallower than the thickness of the compressive stress layer formed by the primary ion exchange. Therefore, it is necessary to first determine the depth of the primary ion exchange of the sample by EDS (energy spectrum analysis) or EPMA (electron probe). The longer the time of the primary ion exchange, the greater the depth of the ion exchange. Then, the depth of laser engraving is designed according to the depth of the ion exchange layer, which is 50 μm to 150 μm higher than the thickness of the primary ion exchange layer. Preferably, in S3, during the laser inner engraving process, the laser wavelength is 355nm~532nm, the laser spot diameter is 10μm~90μm, the laser power is 5W~30W, the pulse frequency is 20kHz~50kHz, the scanning speed is 2mm / s~50mm / s, the engraving depth is 100μm~500μm, and the inner surface processed by the laser inner engraving process should be smaller than the original size of the glass surface to avoid the detachment of the processed part of the glass, and the edge of the internal ion isolation layer should be 2mm~3mm away from the edge of the glass.

[0027] Preferably, in S4, the temperature of the secondary ion exchange is 40°C to 100°C lower than the temperature of the primary ion exchange; Furthermore, in S4, the proportion of KNO3 in the mixed salt is 35%~65%, and the total amount of the mixed salt is 100%.

[0028] For the secondary ion exchange process of glass, the most crucial part lies in accurately exchanging ions to the designed depth, releasing surface compressive stress, and avoiding excessive ion exchange that leads to too low surface compressive stress and loss of the ion enhancement effect. However, ion exchange is a continuous and reciprocal process, so it is difficult for conventional ion exchange processes to accurately control the degree of ion exchange. Therefore, in the present invention, below the glass surface, a new internal surface is created using laser internal engraving technology to truncate the glass ion exchange path. When the glass undergoes secondary ion exchange, the primary ion exchange ions above the internal interface can be fully exchanged, while the concentration of primary ion exchange ions below the internal interface does not decrease, ensuring that the glass still has a good primary ion exchange compressive stress effect. At the same time, laser internal engraving is a non-contact processing technology that does not cause mechanical damage to the material surface and does not generate microcracks on the new internal surface, ensuring the strength of the glass. As a result, while the fracture strength of the glass is increased, the strength stability is still relatively high, further enhancing the practicality and reliability of the engineered stress distribution glass. Additionally, by adjusting the parameters of laser internal engraving, it is easy to adjust the position of the internal interface, thereby effectively controlling the depth of the ion exchange layer and realizing the preparation of ESP engineered stress distribution glass with different parameter requirements.

[0029] The fracture strength of the engineered stress distribution glass prepared by the above method is 450 MPa to 650 MPa, the microhardness is 580 kg / mm 2 ~700 kg / mm 2 , and the Weibull modulus is 58 to 72. It can be seen that the method of the present invention can enhance glass mainly composed of SiO2, effectively improving the mechanical properties and strength concentration degree of the engineered stress distribution glass, and ensuring the stability and reliability of material use.

[0030] Example 1 (1) A glass sample strip with the specific composition shown in Table 1 was used as the experimental substrate. The cut surface of the specimen was polished and the edges were chamfered. Differential scanning calorimetry (DSC) analysis was performed on the glass sample to measure its transformation temperature Tg. In this example, the Tg of the target glass sample was measured to be 585 °C, and the results are as Figure 1 shown.

[0031] Table 1 Composition table of soda-lime-silica glass sample

[0032] (2) According to the Tg temperature of the glass sample, the glass sample was heated to 560 °C in a box-type resistance furnace and annealed for 1 h to eliminate the internal stress in the glass sample matrix.

[0033] (3) According to the Tg temperature of the glass sample, the glass sample was placed in molten KNO3 salt solution at 485 °C and kept for 10 h for the first ion exchange. After completion, the glass sample was taken out and cooled to room temperature, and the surface was cleaned. After detection by EDS energy spectrum analysis, it was confirmed that the thickness of the first ion exchange layer was about 150 μm.

[0034] (4) Using a laser internal engraving device, the parameters were set as follows: the wavelength of the laser was 355 nm, the diameter of the laser spot was 10 μm, the laser power was 5 W, the pulse frequency was 20 kHz, the scanning speed was 2 mm / s, and the engraving depth was 100 μm, that is, 50 μm above the deepest part of the first ion exchange of the glass, a new inner surface was processed. The distance from the edge of the inner surface to the edge of the glass was 2 mm.

[0035] (5) The crucible was heated to 445 °C, and a mixed salt of KNO3 and NaNO3 was added to the crucible. The proportion of KNO3 was 35%. When the mixed molten salt melted, the glass sample sheet was put into the crucible and immersed in the molten salt. Wait for 5 min to make the temperature uniform, then start timing. After 15 min, the second ion exchange was completed. The glass sample was taken out and cooled to room temperature, and the surface was cleaned.

[0036] (5) After the second ion exchange, in the glass above the inner surface of the glass, the first exchange ions were exchanged out again, unloading the surface compressive stress; in the glass below the inner surface of the glass, the first exchange ions were basically retained. Since the temperature of the second ion exchange was lower and the ions did not diffuse deeper into the glass, the strengthening effect of the first exchange of the glass was better retained, and the maximum compressive stress layer of the glass was transferred from the outermost surface of the glass to the inner surface of the glass deeper inside.

[0037] (6) The glass after the second exchange was tested, and its fracture strength was 450 MPa, the microhardness was 580 kg / mm 2 , and the Weibull modulus was 58.

[0038] See Figure 1 From Figure 1 it can be seen that the Tg of the soda-lime-silica glass is 585 °C.

[0039] See Figure 2 From Figure 2 it can be seen that the effective thickness of the first ion exchange layer is about 150 μm (the Na / K ion exchange part).

[0040] See Figure 3 From Figure 3It can be seen that by processing the inner surface in the glass with a laser internal engraving device, the ion exchange deeper in the glass is blocked, enabling the compressive stress deeper inside to be retained, thereby strengthening the glass. By adjusting the parameters of the laser internal engraving device, the depth of the internal gap can be controlled, thus effectively controlling the depth of the ion exchange stress layer and achieving the preparation of ESP engineering stress distribution glass with different parameter requirements.

[0041] See Figure 4 , from Figure 4 It can be seen that the laser internal engraving on the surface blocks the ion exchange deeper inside, enabling the compressive stress deeper in the glass to be retained, thereby strengthening the glass.

[0042] See Figure 5 , from Figure 5 It can be seen that after the microhardness test, the indentation of the original glass sheet shows a typical Maltese cross effect, and the cracks generated by the indentation are relatively long; after the first ion exchange, stress propagation occurs after the indenter is unloaded, causing the glass around the indentation to break; the indentation of the second ion exchange glass shows Maltese cross extended cracks, and the size of these cracks expands significantly. This is because after the second exchange, the maximum compressive stress layer of the glass moves to the subsurface of the glass, the surface compressive stress is small, and the inhibitory effect on surface cracks is also small, so the crack propagation is relatively large, presenting the appearance of a petal.

[0043] See Figure 6 , from Figure 6 It can be seen that after the three-point bending test, the original glass sheet shows obvious brittle fracture, the strengthening effect of the glass after the first ion exchange is obvious, and the fracture surface shows comminuted failure; after the second ion exchange, crack propagation occurs throughout the fracture surface, and there is an obvious difference between the tensile surface and the compressive surface during loading. The fracture surface of the compressive surface is relatively flat, while the fracture surface of the tensile surface is uneven and there are a large number of cracks.

[0044] Example 2 (1) Grind, polish, and anneal the glass sample strip as described in Experimental Example 1; (2) Change the parameters and perform two ion exchange treatments.

[0045] The conditions for the first ion exchange are: KNO3 molten salt, 475 °C, holding for 48 h; The conditions for the laser internal engraving are: laser internal engraving depth 175 μm, 125 μm higher than the first ion exchange layer, laser wavelength 510 nm, laser spot diameter 55 μm, laser power 20 W, pulse frequency 35 kHz, scanning speed 30 mm / s, and the distance from the inner surface edge to the glass edge is 2.5 mm.

[0046] The conditions for the second ion exchange are: use 48% KNO3 mixed molten salt, exchange temperature 415 °C, holding for 30 min.

[0047] The glass after secondary ion exchange in this embodiment has a fracture strength of 700 MPa and a microhardness of 680 kg / mm 2 , and a Weibull modulus of 65.

[0048] Example 3 (1) Grind, polish, and anneal the glass sample strip as described in Experimental Example 1; (2) Change the parameters and perform two ion exchange treatments.

[0049] The conditions for the first ion exchange are: KNO3 molten salt, 465 °C, and heat preservation for 60 h; The conditions for laser internal engraving are: laser internal engraving depth of 250 μm, 150 μm higher than the first ion exchange layer, laser wavelength of 532 nm, laser spot diameter of 90 μm, laser power of 30 W, pulse frequency of 50 kHz, scanning speed of 50 mm / s, and the distance from the inner surface edge to the glass edge of 3 mm.

[0050] The conditions for the second ion exchange are: use a 65% KNO3 mixed molten salt, exchange temperature of 365 °C, and heat preservation for 45 min.

[0051] The glass after secondary ion exchange in this embodiment has a fracture strength of 585 MPa and a microhardness of 700 kg / mm 2 , and a Weibull modulus of 72.

[0052] In summary, the present invention discloses a method for preparing glass with a stable high-strength engineering stress distribution, belonging to the technical field of glass technology. This method uses a sodium-calcium-silicate glass sample as the glass sample matrix and improves the fracture strength and its stability of the glass sample through secondary ion exchange. Although single ion exchange can improve the glass strength, the increased dispersion of the strength brings many unstable factors to process design and engineering applications. First, through the first ion exchange, the Na + on the glass surface is exchanged with K + in the molten salt to improve the strength and microhardness of the sodium-calcium-silicate glass. Secondly, through the first ion exchange again, the K + on the glass surface is replaced. At this time, a gap is formed in the glass by laser internal engraving to truncate the K + ion diffusion path, and the K + ions under the gap are retained, ensuring the transfer of the maximum compressive stress layer of the glass towards the interior of the glass. Although the surface hardness, fracture toughness, and other mechanical properties of the sodium-calcium-silicate glass decrease compared with the first exchange at this time, compared with the unexchanged sodium-calcium-silicate glass, the improvement in mechanical properties is still significant, and the stability of the properties is significantly enhanced, ensuring the stability and reliability of material use.

[0053] The above content is only for explaining the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A high-strength and stable engineering stress distribution glass, characterized in that: The glass is prepared by a secondary ion exchange method and comprises an ion isolation layer which is located inside a primary ion exchange layer of the glass.

2. The high-strength and stable engineered stress distribution glass according to claim 1, characterized in that: The thickness of the ion isolation layer is 100 μm to 500 μm, and the boundary of the ion isolation layer is 2 mm to 3 mm away from the glass boundary.

3. The high-strength and stable engineered stress distribution glass according to claim 1, characterized in that: The ion isolation layer is below the glass surface and 50 μm to 150 μm higher than the deepest part of the primary ion exchange layer.

4. The high-strength and stable engineered stress distribution glass according to claim 3, characterized in that: The deepest part of the primary ion exchange layer is detected by EDS or EPMA.

5. The high-strength and stable engineered stress distribution glass according to claim 1, characterized in that: The ion isolation layer is prepared by a laser inner engraving method, the laser wavelength is 355nm~532nm, the laser spot diameter is 10μm~90μm, the laser power is 5W~30W, the pulse frequency is 20kHz~50kHz, and the scanning speed is 2mm / s~50mm / s.

6. A method for preparing high-strength and stable engineering stress distribution glass, characterized in that: The specific steps are as follows: Perform an ion exchange on the glass sample to be strengthened: The ion isolation layer is prepared inside the glass primary ion exchange layer by using the laser inner engraving method; A glass sample with an ion barrier layer is subjected to secondary ion exchange to obtain a high-strength and stable engineering stress distribution glass.

7. The method for preparing a high-strength and stable engineering stress distribution glass according to claim 6, characterized in that: The ion isolation layer is below the glass surface and 50 μm to 150 μm higher than the deepest part of the primary ion exchange layer. The thickness of the ion isolation layer is 100 μm to 500 μm. The boundary of the ion isolation layer is 2 mm to 3 mm away from the glass boundary.

8. The method for preparing a high-strength and stable engineering stress distribution glass according to claim 6, characterized in that: The ion isolation layer is prepared by a laser inner engraving method, the laser wavelength is 355nm~532nm, the laser spot diameter is 10μm~90μm, the laser power is 5W~30W, the pulse frequency is 20kHz~50kHz, and the scanning speed is 2mm / s~50mm / s.

9. The method for preparing a high-strength and stable engineering stress distribution glass according to claim 6, characterized in that: The primary ion exchange temperature is 100° C. to 120° C. lower than the glass transition temperature, and the primary ion exchange time is 10 h to 60 h.

10. The method for preparing a high-strength and stable engineering stress distribution glass according to claim 6, characterized in that: The molten salt used in the secondary ion exchange is a mixed salt of KNO3 and NaNO3, the proportion of KNO3 in the mixed salt is 35%~65%, and the total amount of the mixed salt is 100%; during the secondary ion exchange, the ion exchange temperature inside the glass is 40℃~60℃ lower than the primary ion exchange temperature, and the time of the secondary ion exchange is 15min~45min.

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