A reinforced microcrystalline glass, its preparation method and application

Abstract

This invention provides a reinforced microcrystalline glass, its preparation method, and its application. The reinforced microcrystalline glass contains a lithium feldspar crystal phase and a lithium disilicate crystal phase. The reinforced microcrystalline glass has a compressive stress layer formed by chemical strengthening on its surface and a tensile stress layer inside. The reinforced microcrystalline glass satisfies the following conditions: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); DOL_0≥0.187t; 1.01%≥Δα≥0.65%, Δα=5×10 ‑5 ×|CT_AV|+0.0026. Under 80-grit sandpaper conditions, the average drop failure height of the reinforced microcrystalline glass can reach 1.30–1.80 m. The reinforced microcrystalline glass of this invention has significantly improved drop resistance on rough surfaces compared to existing technologies and can be used as a protective cover material for smartphones and other smart terminal products.

Description

Technical Field

[0001] This invention relates to the field of lithium aluminum silicon microcrystalline glass, and more particularly to a microcrystalline glass with excellent impact resistance and its preparation method. This patent application is a divisional application of the patent application with application number 202210869057.X, application date July 22, 2022, entitled "A Reinforced Microcrystalline Glass and its Preparation Method and Application". Technical Background

[0002] With the advent of the smartphone era, mobile phones have become an indispensable communication tool in daily life. As the number of mobile phone users increases year by year, the pace of mobile phone upgrades and replacements is also constantly accelerating to meet user demands and enhance the user experience. As mobile phones become increasingly thinner and lighter, the performance requirements for their cover glass are gradually increasing. Among these, microcrystalline glass, with lithium feldspar and lithium disilicate as its main crystalline phases, can achieve a crystallinity greater than 70wt%, and its transmittance in the 360-740nm light band is close to that of commonly used lithium aluminum silicon glass. Furthermore, it can be chemically strengthened using a salt bath to further improve its mechanical properties such as drop resistance and impact resistance, thus standing out and gaining widespread attention in the cover glass industry.

[0003] The reason why cover glass breaks during use is usually due to a fall from a height, causing the glass to collide with a sharp object (such as fine sand, cement, or small stones). The glass surface is locally damaged, and microcracks are formed at the point of damage. The cracks extend from the glass surface inward. When the cracks extend through the compressive stress layer of the glass surface and reach the tensile stress layer, the cracks will expand rapidly in the tensile stress zone, causing the cracks to penetrate the entire glass, thus causing the glass to break or fracture.

[0004] Existing patents describe microcrystalline glass with lithium feldspar and lithium disilicate as the main crystalline phases. These glass types primarily enhance the glass's resistance to damage by increasing CT and DOL_0 after strengthening, thereby suppressing crack propagation.

[0005] CN201980020541.1, through a specific strengthening method, achieves a surface maximum compressive stress absolute value that is 1.8 to 2.2 times the absolute value of the maximum central tensile stress, with a maximum CT value reaching 140 MPa.

[0006] CN202010348413.4 achieves a maximum CT value of 120 MPa, DOL_0 ≥ 100 μm, and a maximum tensile stress linear density of 50000 MPa / mm through two-step mixed salt strengthening. Summary of the Invention

[0007] However, the drop resistance of these glasses is still insufficient, making it difficult to meet the performance requirements of current mid-to-high-end mobile phones.

[0008] In response to the problem that the drop resistance of existing microcrystalline glass is insufficient to meet the requirements, the inventors, after extensive research, have provided a microcrystalline glass with superior drop resistance, which is significantly improved compared to existing technologies.

[0009] Specifically, the present invention provides the following technical solution:

[0010] 1. A reinforced glass-ceramic, wherein the reinforced glass-ceramic contains a lithium feldspar crystal phase and a lithium disilicate crystal phase, and the reinforced glass-ceramic has a compressive stress layer formed by chemical strengthening on the surface and a tensile stress layer in the interior.

[0011] The reinforced microcrystalline glass satisfies:

[0012] DOL_0≥0.187t, where t is the thickness of the reinforced microcrystalline glass;

[0013] 1.01%≥Δα≥0.65%, Δα=5×10 -5 ×|CT_AV|+0.0026;

[0014] (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|);

[0015] in:

[0016] Surface CS: Surface compressive stress, in MPa;

[0017] CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa;

[0018] CT_AV: The absolute value of the average tensile stress in the tensile stress layer, in MPa;

[0019] CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and

[0020] DOL_0: Depth of compressive stress layer, in μm.

[0021] 2. The reinforced microcrystalline glass according to technical solution 1, wherein, by weight, the tensile stress layer of the reinforced microcrystalline glass contains the following percentages of oxides:

[0022] SiO2: 65.00~75.00%,

[0023] Al2O3: 5.00–10.00%,

[0024] P2O5: 1.00~5.00%,

[0025] CaO: 0.10–3.00%,

[0026] ZrO2: 1.00~10.00%,

[0027] Na2O: 0~5.00%,

[0028] Li2O: 5.00~15.00%,

[0029] K2O: 0.10–3.00%, and

[0030] B2O3: 0–4.00%.

[0031] 3. The reinforced microcrystalline glass according to technical solution 1, wherein, by weight, the tensile stress layer of the reinforced microcrystalline glass contains the following percentages of oxides:

[0032] SiO2: 68.00~72.00%,

[0033] Al2O3: 5.00–10.00%,

[0034] P2O5: 1.00~3.00%,

[0035] CaO: 0.10–1.00%,

[0036] ZrO2: 2.00~8.00%,

[0037] Na2O: 0~1.00%,

[0038] Li2O: 8.00~13.00%,

[0039] K2O: 0.10–1.00%, and

[0040] B2O3: 0–2.00%.

[0041] 4. The reinforced microcrystalline glass according to technical solution 1, wherein, by weight, the tensile stress layer of the reinforced microcrystalline glass contains the following percentages of oxides:

[0042] SiO2: 70.00~72.00%,

[0043] Al2O3: 6.00–8.00%,

[0044] P2O5: 1.50–3.00%,

[0045] CaO: 0.50–1.00%,

[0046] ZrO2: 5.00~7.00%,

[0047] Na₂O: 0.05–0.60%,

[0048] Li2O: 9.00~12.00%,

[0049] K2O: 0.10–0.50%, and

[0050] B2O3: 0.10–1.00%.

[0051] 5. The reinforced microcrystalline glass according to technical solution 1, wherein, by weight, the tensile stress layer of the reinforced microcrystalline glass contains the following percentages of oxides:

[0052] SiO2: 70.06~71.65%,

[0053] Al2O3: 7.24–7.43%,

[0054] P2O5: 2.49–2.83%,

[0055] CaO: 0.77–0.98%,

[0056] ZrO2: 5.40–6.11%,

[0057] Na2O: 0.06–0.31%,

[0058] Li2O: 11.10~11.95%,

[0059] K2O: 0.13–0.37% and

[0060] B2O3: 0.21–0.91%.

[0061] 6. The reinforced microcrystalline glass according to technical solution 1, wherein the total content of the lithium feldspar crystal phase and the lithium disilicate crystal phase in the reinforced microcrystalline glass is 75 wt% or more.

[0062] 7. The reinforced microcrystalline glass according to any one of technical solutions 1-6, wherein, at a thickness of 0.7 mm, the reinforced microcrystalline glass is subjected to a sandpaper drop test using 80-grit sandpaper, and the average sandpaper drop height resisted by the reinforced microcrystalline glass is 1.30 to 1.80 m.

[0063] 8. The reinforced microcrystalline glass according to any one of technical solutions 1-6, wherein, at a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent and has a transmittance of not less than 90.00% for light with a wavelength of 550 nm.

[0064] 9. The method for preparing reinforced microcrystalline glass according to any one of technical solutions 1-8, characterized in that it includes the following steps:

[0065] (1) Preparation of substrate glass: After mixing the various substances of glass raw materials, a clarifying agent is added, the mixture is melted and annealed to obtain substrate glass;

[0066] (2) Preparation of microcrystalline glass: The substrate glass obtained in step (1) is subjected to nucleation and crystallization treatments to obtain microcrystalline glass;

[0067] (3) The microcrystalline glass obtained in step (2) is cold-processed to obtain a polished sheet; and

[0068] (4) The polished sheet obtained in step (3) is subjected to chemical strengthening treatment to obtain reinforced microcrystalline glass.

[0069] 10. According to the preparation method described in technical solution 9, in step (1), the annealing temperature is 450-600℃, preferably 450-550℃, and the annealing time is 6-240 hours, preferably 6-120 hours. Annealing is divided into four stages: heating, holding, slow cooling, and rapid cooling. Theoretically, at a certain temperature, the longer the annealing time, the less residual stress there will be. However, considering the time cost, the time should not be too long. Different specifications of sample bricks require different annealing times to reduce the thermal stress of the sample bricks to a usable range. The larger the sample brick size, the longer the required annealing time.

[0070] 11. According to the preparation method described in technical solution 9 or 10, in step (2), when performing nucleation treatment, the nucleation temperature is 500-700℃, preferably 540-570℃, and the preferred nucleation treatment time is 10-1440min.

[0071] 12. According to the preparation method described in technical solution 11, in step (2), when performing nucleation treatment, the temperature is increased to the nucleation temperature at a heating rate of 5 to 20 °C / min, preferably at a heating rate of 10 °C / min.

[0072] 13. According to the preparation method described in technical solution 9 or 10, in step (2), when crystallization is performed, the crystallization temperature is 640-750℃, preferably 660-740℃, or 670-740℃, and the crystallization time is preferably 5-1440 min.

[0073] 14. The preparation method according to technical solution 13, wherein in step (2), when performing crystallization treatment, the temperature is increased to the crystallization temperature at a heating rate of 5 to 20 °C / min, preferably at a heating rate of 10 °C / min.

[0074] 15. According to the preparation method described in technical solution 9 or 10, in step (4), the polished sheet obtained in step (3) is chemically strengthened in a pure sodium salt or lithium sodium potassium mixed salt bath at 380-550°C, preferably for 1-24 hours.

[0075] 16. According to the preparation method described in technical solution 15, in step (4), the sodium ions in the salt bath are provided by any one or more of sodium nitrate, sodium sulfate and sodium carbonate, the potassium ions are provided by any one or more of potassium nitrate, potassium sulfate and potassium carbonate, and the lithium ions are provided by any one or more of lithium nitrate, lithium sulfate and lithium carbonate.

[0076] 17. The preparation method according to technical solution 15 or 16, wherein the composition of the lithium-sodium-potassium mixed salt bath is: by mass ratio, it contains 0.1-100 wt% NaNO3 and 0-99.9 wt% KNO3, and by mass ratio, it contains 0-10 wt% LiNO3 relative to the total mass of NaNO3 and KNO3.

[0077] 18. The preparation method according to technical solution 15 or 16, wherein the composition of the lithium-sodium-potassium mixed salt bath is: by mass ratio, it contains 30-95 wt% NaNO3 and 5-70 wt% KNO3, and by mass ratio, it contains 0.01-1 wt%, preferably 0.01-0.1 wt% LiNO3.

[0078] 19. According to the preparation method described in technical solution 15, the chemical strengthening treatment in step (4) is performed 1 to 3 times.

[0079] 20. According to the preparation method described in technical solution 9 or 10, in step (1), the clarifying agent is selected from any one or more substances selected from NaCl, Sb2O3, As2O3, nitrates, and sulfates, preferably added to the glass at a mass ratio of 0.10-1.00 wt%, more preferably added to the glass at a mass ratio of 0.50-1.00 wt%; and / or

[0080] In process (1), the material is melt-formed at 1400-1650°C.

[0081] 21. The reinforced microcrystalline glass obtained by the preparation method described in any one of technical solutions 9-20.

[0082] 22. The application of the reinforced microcrystalline glass described in any one of technical solutions 1-8 or the reinforced microcrystalline glass described in technical solution 21 as a protective cover in mobile devices.

[0083] The reinforced microcrystalline glass provided by this invention has a stress characteristic that satisfies 1.01% ≥ Δα ≥ 0.65% (Δα = 5 × 10⁻⁶). -5When ×|CT_AV|+0.0026), (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|), and DOL_0≥0.187t, the average drop resistance of the reinforced microcrystalline glass on rough surfaces can reach 1.30~1.80m under 80-grit sandpaper conditions. The reinforced microcrystalline glass of this invention exhibits significantly improved drop resistance on rough surfaces compared to existing technologies and can be used as a protective cover material for smartphones and other smart terminal products. Attached Figure Description

[0084] Figure 1 This is the DSC image of the substrate glass in Embodiment 3 of the present invention, heated to 1000°C in nitrogen at a rate of 10°C / min;

[0085] Figure 2 This is a transmittance curve of the microcrystalline glass of Embodiment 3 of the present invention in the range of 200nm to 1000nm.

[0086] Figure 3 This is the X-ray diffraction pattern of the microcrystalline glass of Embodiment 3 of the present invention;

[0087] Figure 4 This is a schematic diagram of the reinforced microcrystalline glass of the present invention breaking upon impact. Detailed Implementation

[0088] In order to solve the problem of poor impact resistance of existing microcrystalline glass, the present invention provides a transparent microcrystalline glass with lithium feldspar and lithium disilicate as the main crystalline phases. It can be chemically strengthened to obtain a strengthened microcrystalline glass. The strengthened microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface and a tensile stress layer inside. Since the tensile stress layer has not undergone ion exchange, its composition is the same as that of the transparent microcrystalline glass before strengthening.

[0089] This reinforced microcrystalline glass meets the following stress characteristics:

[0090] DOL_0≥0.187t, where t is the thickness of the glass-ceramic;

[0091] 1.01%≥Δα≥0.65%, Δα=5×10 -5 ×|CT_AV|+0.0026;

[0092] (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|);

[0093] Δα is a function that is positively correlated with the absolute value of the average tensile stress. When Δα > 1.01% in reinforced glass-ceramics, the tensile stress of the glass-ceramic products is too high, which will cause the glass-ceramic products to spontaneously explode. When Δα < 0.65%, the tensile stress of the glass-ceramic products is low and the impact resistance is poor.

[0094] (CS_50 / DOL_0) / (Surface CS / |CT_CV|) represents the combined relationship between surface compressive stress, central tensile stress, and stress layer depth. When (CS_50 / DOL_0) < 0.332 × (Surface CS / |CT_CV|), the glass is prone to microcracks when in contact with sharp objects, which then propagate inwards, leading to a decrease in the glass's impact resistance.

[0095] DOL_0 is the depth of the compressive stress layer (referred to as "compressive stress layer depth"). When DOL_0 < 0.187t, the compressive stress layer is relatively shallow. When the glass comes into contact with a sharp object, the resulting cracks are more likely to penetrate the compressive stress layer and reach the tensile stress zone, thereby reducing the glass's impact resistance.

[0096] In this invention, those skilled in the art can select the thickness of the reinforced glass-ceramic according to their needs. For example, in some embodiments, the thickness of the reinforced glass-ceramic is 0.2-2.0 mm. The change in the thickness of the glass-ceramic before and after chemical strengthening is very small and can be ignored.

[0097] The composition range of the reinforced microcrystalline glass involved in this invention, by weight, is such that the tensile stress layer of the reinforced microcrystalline glass contains the following percentages of oxides:

[0098] SiO2: 65.00~75.00%

[0099] Al2O3: 5.00–10.00%

[0100] P2O5: 1.00–5.00%

[0101] CaO: 0.10–3.00%

[0102] ZrO2: 1.00~10.00%

[0103] Na2O: 0–5.00%

[0104] Li2O: 5.00–15.00%

[0105] K2O: 0.10–3.00%

[0106] B2O3: 0–4.00%.

[0107] Preferably, the tensile stress layer of the reinforced microcrystalline glass contains the following percentage of oxides:

[0108] SiO2: 68.00–72.00%, preferably 70.00–72.00%

[0109] Al2O3: 5.00–10.00%, preferably 6.00–8.00%

[0110] P2O5: 1.00–3.00%, preferably 1.50–3.00%

[0111] CaO: 0.10–1.00%, preferably 0.50–1.00%

[0112] ZrO2: 2.00–8.00%, preferably 5.00–7.00%

[0113] Na₂O: 0–1.00%, preferably 0.05–0.60%

[0114] Li2O: 8.00–13.00%, preferably 9.00–12.00%

[0115] K2O: 0.10–1.00%, preferably 0.10–0.50%

[0116] B2O3: 0–2.00%, preferably 0.10–1.00%.

[0117] More preferably, the tensile stress layer of the reinforced microcrystalline glass contains the following percentage of oxides:

[0118] SiO2: 70.06~71.65%,

[0119] Al2O3: 7.24–7.43%,

[0120] P2O5: 2.49–2.83%,

[0121] CaO: 0.77–0.98%,

[0122] ZrO2: 5.40–6.11%,

[0123] Na2O: 0.06–0.31%,

[0124] Li2O: 11.10~11.95%,

[0125] K2O: 0.13–0.37% and

[0126] B2O3: 0.21–0.91%.

[0127] In the reinforced glass-ceramic of this invention, the total content of the lithium feldspar crystal phase and the lithium disilicate crystal phase accounts for more than 75 wt%, preferably greater than or equal to 79 wt%, and more preferably greater than or equal to 80 wt%. It may also contain impurity phases such as quartz, spodumene, and lithium metasilicate. Lithium disilicate (Li₂Si₂O₅) is an orthorhombic crystal, often exhibiting a flattened shape with distinct dissociation planes. Due to its irregular orientation, this crystal phase forces cracks to propagate along distorted grain boundaries, reducing the possibility of crack propagation. Lithium feldspar (LiAlSi₄O₅)... 10 It is a monoclinic crystal, with Li and O in tetrahedral coordination. Lithium feldspar can undergo chemical strengthening in a salt bath, where Na... + Li replacing lipite + .

[0128] In some embodiments, the total content of the lithium feldspar crystal phase and the lithium disilicate crystal phase in the reinforced microcrystalline glass of the present invention is 79 wt% to 97 wt%. In some embodiments, the total content of the lithium feldspar crystal phase and the lithium disilicate crystal phase in the reinforced microcrystalline glass of the present invention is 79 wt%, 80.00 wt%, 81.00 wt%, 82.00 wt%, 83.00 wt%, 84.00 wt%, 85.00 wt%, 86.00 wt%, 87.00 wt%, 88.00 wt%, 89.00 wt%, 90.00 wt%, 91.00 wt%, 92.00 wt%, 93.00 wt%, 94.00 wt%, 95.00 wt%, 96.00 wt%, or 97.00 wt%. Alternatively, it can be any proportion within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges as needed, as long as the glass with the desired performance of the present invention can be obtained.

[0129] In some embodiments, the average grain size in the strengthened microcrystalline glass is 10nm-50nm, preferably 10nm-30nm, and more preferably 10nm-20nm. In some embodiments, the average grain size can be 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, 35nm, 38nm, 40nm, 45nm, 48nm, or 50nm, or any proportion within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges as needed, as long as the microcrystalline glass of the present invention can be obtained.

[0130] The reinforced microcrystalline glass involved in this invention also has the following stress characteristics:

[0131] Surface pressure (CS): 200–680 MPa;

[0132] CS_50: 100~400MPa;

[0133] CS_100: 20~150MPa;

[0134] |CT_CV|:50~210MPa;

[0135] |CT_AV|:55~150MPa;

[0136] CT_LD: 45000~90000MPa / mm.

[0137] Strengthening the drop resistance / impact resistance of microcrystalline glass:

[0138] At a thickness of 0.7 mm, the reinforced microcrystalline glass provided by the present invention was subjected to a sandpaper drop test using 80-grit sandpaper. The average sandpaper drop height resistance of the reinforced microcrystalline glass was 1.30 to 1.80 m.

[0139] At a thickness of 0.7 mm, the reinforced microcrystalline glass provided by the present invention was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m.

[0140] At a thickness of 0.7 mm, the reinforced microcrystalline glass provided by the present invention was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

[0141] Enhance the optical properties of glass-ceramics:

[0142] The transmittance of the reinforced microcrystalline glass was tested under light wavelengths of 200–1000 nm. Figure 2 As shown. By Figure 2 It can be seen that, in the visible light wavelength range, this reinforced microcrystalline glass has a high transmittance and good transparency.

[0143] At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent with a transmittance of not less than 90.00% for light with a wavelength of 550 nm.

[0144] This invention prepares microcrystalline glass with high crystal content by ceramicizing lithium aluminum silicon glass, and then chemically strengthens the microcrystalline glass in pure sodium salt or lithium sodium potassium mixed salt, so that the glass can meet the above stress requirements after strengthening and obtain better impact resistance.

[0145] SiO2, as a glass network-forming oxide, is an indispensable component in the glass network structure. Appropriately increasing the SiO2 content can enhance the stability and mechanical strength of the glass. However, excessive SiO2 will increase the viscosity of the glass, causing difficulties in melting. Therefore, a SiO2 content of 65.00–75.00 wt% is most effective in increasing the stability and formability of the glass. In some embodiments, the weight percentage of SiO2 is 68.00%–72.00%. In some embodiments, the weight percentage of SiO2 is 70.00%–72.00%. In some embodiments, the weight percentage of SiO2 is 70.06%–71.65%. In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight percentage, 65.00–71.00%, 66.00–71.00%, 67.00%–71.00%, 68.00–71.00%, 68.00%–69.50%, 67.00%–69.50%, 68.00%–71.00%, 67.30%–71.00%, 67.50%–71.00%, or 67.70%–71.00%. 1.00%, 68.20%–71.00%, 68.50%–71.00%, 68.80%–71.00%, 69.00%–71.00%, 69.00%–69.80%, 69.00%–69.50%, 69.00%–69.30%, 69.50–70.00%, 70.00–70.50%, 71.00–71.50%, or 71.50–72.00% SiO2. In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight percentage, 65.00%, 66.00%, 67.00%, 67.10%, 67.20%, 67.30%, 67.40%, 67.50%, 67.60%, 67.70%, 67.80%, 67.90%, 68.00%, 68.10%, 68.20%, 68.30%, 68.40%, 68.50%, 68.60%, 68.60%, 68.20%, 68.30%, 68.40%, 68.50%, 68.60%, 68.40%, 68.50%, 68.60%, 68.50%, 68.60%, 68.00%, 68.10%, 68.20%, 68.30%, 68.40%, 68.50%, 68.6 ...40%, 68 SiO2 of 68.70%, 68.80%, 68.90%, 69.00%, 69.10%, 69.20%, 69.30%, 69.40%, 69.50%, 69.60%, 69.70%, 69.80%, 69.90%, 71.00%, 72.00%, 73.00%, 74.00%, or 75.00%, or SiO2 falling within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the embodiments, any of the above ranges can be combined with any other range.

[0146] Al₂O₃ is an intermediate oxide in glass formation, which can improve the chemical stability of glass. Furthermore, since [AlO₄] has a larger volume than [SiO₄], it provides more space for ion exchange; therefore, alumina can promote ion exchange. However, excessive Al₂O₃ tends to increase the viscosity of the glass, and the presence of alkaline earth metals can increase the tendency for crystallization. Therefore, the Al₂O₃ content is controlled between 5.00 and 10.00 wt%. In some embodiments, the weight percentage of Al₂O₃ can be 6.00% to 8.00%. In some embodiments, the weight percentage of Al₂O₃ can be 7.24% to 7.43%. In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain 5.00%, 5.30%, 5.50%, 5.80%, 6.00%, 6.30%, 6.50%, 6.80%, 7.00%, 7.30%, 7.50%, 7.80%, 8.00%, 8.30%, 8.50%, 8.80%, 9.00%, 9.30%, 9.50%, 9.80%, or 10.00% Al2O3 by weight, or Al2O3 within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0147] P2O5 can act as a glass network forming oxide, promoting phase separation in glass and thus affecting crystallization. In transparent microcrystalline glass of the Li2O-Al2O3-SiO2 system, the P2O5 content is controlled at 1.00-5.00 wt%. In some embodiments, the weight percentage of P2O5 can be 1.00% to 3.00%; in some embodiments, the weight percentage of P2O5 can be 1.50% to 3.00%; in some embodiments, the weight percentage of P2O5 can be 2.49% to 2.83%; in some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain 1.00%, 1.20%, 1.50%, 1.70%, 1.80%, 2.00%, 2.20%, 2.50%, 2.80%, 3.00%, 3.20%, 3.50%, 3.80%, 4.00%, 4.20%, 4.50%, 4.80%, or 5.00% P2O5 by weight, or P2O5 within a range defined by any two of the above specific values ​​as endpoints. It should be understood that, in embodiments, any of the above ranges can be combined with any other ranges.

[0148] ZrO2 is an intermediate oxide in glass formation, which can improve the chemical stability, hardness, scratch resistance, and drop resistance of glass. Furthermore, due to its high cation charge and strong field, ZrO2 has a significant accumulation effect on the glass structure and is commonly used as a nucleating agent in glass-ceramics. However, excessive ZrO2 will greatly increase the viscosity of the glass, affecting its formability. Therefore, in transparent glass-ceramics of the Li2O-Al2O3-SiO2 system, the ZrO2 content is controlled between 1.00 and 10.00 wt%. In some embodiments, the weight percentage of ZrO2 can be 2.00% to 8.00%; in some embodiments, the weight percentage of ZrO2 can be 5.00% to 7.00%; in some embodiments, the weight content of ZrO2 can be 5.40% to 6.11%; in some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight, 1.00%, 1.20%, 1.40%, 1.60%, 1.80%, 2.00%, 2.20%, 2.40%, 2.60%, 2.80%, 3.00%, 3.20%, 3.40%, 3.60%, 3.80%, 4%... ZrO2 concentrations of 0.00%, 4.20%, 4.40%, 4.60%, 4.80%, 5.00%, 5.20%, 5.40%, 5.60%, 5.80%, 6.00%, 6.20%, 6.40%, 6.60%, 6.80%, 7.00%, 7.20%, 7.40%, 7.60%, 7.80%, 8.00%, 8.20%, 8.40%, 8.60%, 8.80%, 9.00%, 9.20%, 9.40%, 9.6%, 9.8%, or 10.0%, or ZrO2 concentrations within a range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the implementation, any of the above ranges can be combined with any other range.

[0149] CaO, as a network oxide in glass formation, helps reduce glass viscosity, inhibits crystallization during glass forming, and improves the low-temperature melting properties of glass. However, excessive CaO can decrease the glass's devitrification resistance. Adding an appropriate amount of CaO can reduce glass viscosity without affecting its crystallization properties; therefore, this application controls the CaO content to be between 0.10 and 3.00 wt%. In some embodiments, the weight percentage of CaO can be between 0.10 and 1.00%. In some embodiments, the weight percentage of CaO can be between 0.50 and 1.00%. In some embodiments, the weight percentage of CaO can be between 0.77 and 0.98%. In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight, 0.10%, 0.15%, 0.18%, 0.20%, 0.25%, 0.28%, 0.30%, 0.35%, 0.38%, 0.40%, 0.45%, 0.48%, 0.50%, 0.55%, 0.58%, 0.60%, 0.65%, or 0.68% of the following: The concentrations of CaO are 0.70%, 0.75%, 0.78%, 0.80%, 0.85%, 0.88%, 0.90%, 0.95%, 0.98%, 1.00%, 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, 2.75%, or 3.00%, or CaO falling within a range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the implementation scheme, any of the above ranges can be combined with any other range.

[0150] Li₂O, Na₂O, and K₂O, as network oxides in glass formation, can improve glass viscosity and promote the melting and clarification of molten glass. Furthermore, Li₂O and Na₂O can undergo ion exchange with the molten salt bath, and their contents are a significant factor affecting glass stress. Additionally, Li₂O is also a precursor to lithium disilicate (Li₂Si₂O₅), lithium metasilicate (Li₂SiO₃), and lithium feldspar (LiAlSi₄O₅). 10 Li₂O, Na₂O, and K₂O are essential chemical components for the formation of crystal phases. However, the free oxygen provided by Li₂O, Na₂O, and K₂O can disrupt the network structure of the glass and affect its intrinsic strength. Therefore, this application aims to control the Li₂O content to be between 5.00 and 15.00 wt%, the Na₂O content to be between 0 and 5.00 wt%, and the K₂O content to be between 0.10 and 3.00 wt%.

[0151] In some embodiments, the Li2O content is controlled between 8.00 and 13.00 wt%; in some embodiments, the Li2O content is controlled between 9.00 and 12.00 wt%; and in some embodiments, the Li2O content is controlled between 11.10 and 11.95 wt%.

[0152] In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight, 5.00%, 5.50%, 6.00%, 6.50%, 7.00%, 7.50%, 8.00%, 8.10%, 8.15%, 8.20%, 8.25%, 8.30%, 8.35%, 8.40%, 8.45%, 8.50%, 8.55%, 8.60%, 8.65%, 8.70%, 8.75%, 8.80%, 8.85%, 8.90%, 8.95%, 8.90%, 8.95%, 9%... 0.00%, 9.10%, 9.15%, 9.20%, 9.25%, 9.30%, 9.35%, 9.40%, 9.45%, 9.50%, 9.55%, 9.60%, 9.65%, 9.70%, 9.75%, 9.80%, 9.85%, 9.90%, 9.95%, 10.00%, 10.10%, 10.15%, 10.20%, 10.25%, 10.30%, 10.35%, 10.40%, 10.45%, 10.50%, 10.55%, 10.60% %, 10.65%, 10.70%, 10.75%, 10.80%, 10.85%, 10.90%, 10.95%, 11.00%, 11.10%, 11.15%, 11.20%, 11.25%, 11.30%, 11.35%, 11.40%, 11.45%, 11.50%, 11.55%, 11.60%, 11.65%, 11.70%, 11.75%, 11.80%, 11.85%, 11.90%, 11.95%, 12.00%, 12. 10%, 12.15%, 12.20%, 12.25%, 12.30%, 12.35%, 12.40%, 12.45%, 12.50%, 12.55%, 12.60%, 12.65%, 12.70%, 12.75%, 12.80%, 12.85%, 12.90%, 12.95%, 13.00%, 13.50%, 14.00%, 14.50%, or 15.00% of Li₂O, or Li₂O falling within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the embodiments, any of the above ranges can be combined with any other range.

[0153] In some embodiments, the Na2O content is controlled between 0.01 and 1.00 wt%; in some embodiments, the Na2O content is controlled between 0.05 and 0.60 wt%; and in some embodiments, the Na2O content is controlled between 0.06 and 0.31 wt%.

[0154] In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24% of the following: %, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.5 3%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0. The concentrations of Na₂O are 82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.90%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.00%, 2.00%, 3.00%, 4.00%, or 5.00%, or Na₂O within a range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the embodiments, any of the above ranges can be combined with any other range.

[0155] In some embodiments, the K2O content is controlled between 0.10 and 1.00 wt%; in other embodiments, the K2O content is controlled between 0.10 and 0.50 wt%.

[0156] In some embodiments, the tensile stress layer of the reinforced glass-ceramic may contain, by weight, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, or 0.30% of the following: 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56% 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82% The K₂O concentrations are 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.90%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.00%, 2.00%, or 3.00%, or K₂O concentrations within a range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the implementation scheme, any of the above ranges can be combined with any other ranges.

[0157] B₂O₃, as a flux in the glass-forming process, can reduce the high-temperature viscosity of glass, accelerate glass refining, and reduce the glass's crystallization ability. However, excessive B₂O₃ can reduce the chemical stability and mechanical strength of the glass. Therefore, the B₂O₃ content is controlled between 0 and 4.00 wt%. In some embodiments, the B₂O₃ content is controlled between 0 and 2.00%. In some embodiments, the B₂O₃ content is controlled between 0.10 and 1.00%. In some embodiments, the B₂O₃ content is controlled between 0.21 and 0.91%. In some embodiments, the tensile stress layer of the reinforced microcrystalline glass may contain, by weight, 0.10%, 0.15%, 0.18%, 0.20%, 0.25%, 0.28%, 0.30%, 0.35%, 0.38%, 0.40%, 0.45%, 0.48%, 0.50%, 0.55%, 0.58%, 0.60%, 0.65%, 0.68%, 0.70%, 0.75%, 0.78%, 0.80%, 0.85%, 0.88%, 0.90%, 0.95% of the following: %, 0.98%, 1.00%, 1.10%, 1.15%, 1.18%, 1.20%, 1.25%, 1.28%, 1.30%, 1.35%, 1.38%, 1.40%, 1.45%, 1.48%, 1.50%, 1.55%, 1.58%, 1.60%, 1.65%, 1.68%, 1.70%, 1.75%, 1.78%, 1.80%, 1.85%, 1.88%, 1.90%, 1.95%, 1.98%, 2.00%, 2.1 0%, 2.15%, 2.18%, 2.20%, 2.25%, 2.28%, 2.30%, 2.35%, 2.38%, 2.40%, 2.45%, 2.48%, 2.50%, 2.55%, 2.58%, 2.60%, 2.65%, 2.68%, 2.70%, 2.75%, 2.78%, 2.80%, 2.85%, 2.88%, 2.90%, 2.95%, 2.98%, 3.00%, 3.10%, 3.15%, 3.18%, 3. 20%, 3.25%, 3.28%, 3.30%, 3.35%, 3.38%, 3.40%, 3.45%, 3.48%, 3.50%, 3.55%, 3.58%, 3.60%, 3.65%, 3.68%, 3.70%, 3.75%, 3.78%, 3.80%, 3.85%, 3.88%, 3.90%, 3.95%, 3.98%, or 4.00% of B2O3, or B2O3 falling within a numerical range defined by any two of the above specific values ​​as endpoints. It should be understood that, in the implementation scheme, any of the above ranges can be combined with any other range.

[0158] Terminology Explanation:

[0159] Substrate glass: Glass that has not undergone nucleation, crystallization, or strengthening treatments.

[0160] Glass-ceramics, also known as glass-ceramics, are a type of solid composite material that contains both glass phase and crystalline phase (microcrystalline phase, crystalline phase) through the targeted and controlled crystallization of a substrate glass.

[0161] Nucleation: The process of growing small crystal nuclei from nucleating material in glass through heat treatment.

[0162] Crystallization: Glass grows into a certain crystal based on crystal nuclei through heat treatment.

[0163] Crystal phase: Crystal phase is the microscopic structure of crystals, and is a general term for the parts composed of a large number of crystalline solid phases.

[0164] CT_LD: Tensile stress linear density, the ratio of the sum of tensile stresses in reinforced glass-ceramics to the glass thickness, as measured by an SLP-2000 stress meter.

[0165] Microcrystalline glass is placed in a salt bath for ion exchange to form a compressive stress layer (i.e., a strengthening layer), while a tensile stress layer is formed inside the glass during the ion exchange process. Specifically, during chemical strengthening, larger ions in the salt bath exchange with smaller ions in the glass, thereby forming a compressive stress layer on the glass surface and a tensile stress layer inside the glass. Compared to the microcrystalline glass before strengthening, the occurrence of ion exchange causes a change in the composition of the compressive stress layer. Since the ion exchange depth is usually less than or equal to the thickness of the compressive stress layer, the composition of the tensile stress layer inside the glass does not change; that is, the composition of the tensile stress layer is the same as that of the microcrystalline glass before strengthening.

[0166] The tensile stress layer has an upper boundary that is a certain distance from the upper surface of the reinforced microcrystalline glass and a lower boundary that is a certain distance from the lower surface of the reinforced glass. The curve plotted with the magnitude of the tensile stress at a point on a line segment within the tensile stress layer that is perpendicular to both the upper and lower boundaries and whose upper and lower endpoints fall on the upper and lower boundaries respectively as the Y-axis and the distance of the corresponding point from the upper boundary as the X-axis is denoted as the tensile stress curve. The ratio of the definite integral of the tensile stress curve to the thickness of the reinforced microcrystalline glass is denoted as the tensile stress linear density, which is also the ratio of the sum of the tensile stresses of the reinforced microcrystalline glass measured by the SLP-2000 stress meter to the glass thickness.

[0167] |CT_AV|: The absolute value of the average tensile stress, specifically the absolute value of the average value of all tensile stresses in the tensile stress layer, obtained by testing with an SLP-2000 stress meter.

[0168] DOL_0: Compression stress layer depth, also known as compressive stress layer depth, refers to the distance from any surface of the glass-ceramic to the position near which the compressive stress is zero, obtained by testing with an SLP-2000 stress meter.

[0169] |CT_CV|: The maximum tensile stress at the center or the absolute value of the maximum tensile stress, specifically the maximum value among all tensile stresses in the tensile stress layer, obtained by testing with an SLP-2000 stress meter.

[0170] Surface compressive stress (CS): After chemical strengthening of glass and ceramics, smaller alkali metal ions on the surface are replaced with larger alkali metal ions. Due to the crowding effect of the larger alkali metal ions, compressive stress is generated on the glass surface, which is called surface compressive stress. Surface CS is measured by an SLP-2000 stress meter.

[0171] CS_50: Compressive stress at a depth of 50 μm from the glass surface.

[0172] CS_100: Compressive stress at a depth of 100 μm from the glass surface.

[0173] Transmittance: The ratio of the radiant energy projected onto and transmitted through an object to the total radiant energy projected onto the object during the process of incident light flux from the incident surface or medium to the other side.

[0174] Refractive index: The ratio of the speed of light in a vacuum to the speed of light in that medium.

[0175] In the embodiments and comparative examples of the present invention, the transmittance of the microcrystalline glass at a wavelength of 550 nm is the average transmittance measured at a wavelength of 550 nm for multiple glass samples from the same batch. At least 5 samples from each batch of microcrystalline glass are tested.

[0176] SOC: Photoelastic coefficient. Photoelasticity mainly refers to the anisotropic birefringence phenomenon that occurs in transparent materials when subjected to stress. By measuring the photoelastic coefficient and birefringence, the value of the residual stress (MPa) inside the material can be obtained.

[0177] Instruments and testing methods

[0178] Glass thickness: determined by micrometer measurement. The thickness change of the glass-ceramic before and after chemical strengthening is very small and can be ignored.

[0179] Crystal content testing: The microcrystalline glass sample was tested using an X-ray diffractometer to obtain the XRD diffraction peak curve. The test result file (RAW format) from the X-ray diffractometer (Shimadzu XRD-6000) was then imported into X-ray diffraction data refinement software (such as Gsas, Fullprof, Maud) for fitting and calculation. The crystal content in the microcrystalline glass sample can then be obtained. The ratio of the fitted crystal phase peak area to the fitted total peak area is the crystal content. The X-ray diffractometer used in this invention is the Shimadzu XRD-6000. The diffraction angle range used in the test was 2θ = 10–50°, the scanning speed was 6° / min, the operating voltage was 40KV, and the operating current was 30mA.

[0180] The average grain size is obtained by testing the glass-ceramic sample with an X-ray diffractometer and using the Scherrer formula D=Kλ / (βcosθ) to obtain the average grain size from the XRD test results, where λ is the X-ray wavelength, β is the peak half-width at half-maximum, and K=0.89.

[0181] Transmittance test: The transmittance of the microcrystalline glass was tested using professional testing instruments according to the standard GB / T 7962.12-2010 "Test Methods for Colorless Optical Glass Part 12: Intraspectral Transmittance". The testing instruments used in this invention are the Konica Minolta CM-3600A spectrophotometer and the Shimadzu UV-2600 UV-Vis spectrophotometer.

[0182] Surface compressive stress (surface CS), CS_50, CS_100, CT_AV, CT_CV, and DOL_0 were tested using a Luceo SLP-2000 stress meter (Orihara, Japan). The light source wavelength was 518 nm, SOC = 25.5 (nm / cm) / MPa, refractive index = 1.54, and exposure time was 300 seconds. μ sec.

[0183] When testing surfaces CS, CS_50, CS_100, CT_AV, CT_CV, and DOL_0, the specific refractive liquid for each surface needs to be applied to the stress meter. The reinforced microcrystalline glass product should then be wiped clean and placed on the test path to measure its values. The refractive index of the refractive liquid used in the SLP-2000 is 1.51.

[0184] CT_LD is related to glass sheet thickness, strengthening depth, and average tensile stress, and can be used to evaluate the drop resistance of glass sheets. The CT_LD satisfies the following formula:

[0185]

[0186] Where d represents the thickness of the microcrystalline glass sheet (the glass thickness in the embodiments and comparative examples below is 0.7 mm), in mm; DOL_0 represents the depth of the compressive stress layer, in μm; CT_AV represents the internal average tensile stress, which is taken as its absolute value in the calculation, in MPa.

[0187] Differential scanning calorimetry (DSC) testing: The sample was ground into powder and passed through a 200-mesh sieve; the test conditions were: room temperature to 1000℃, heating rate of 10℃ / min; the test instrument was a Mettler Toledo TGA / DSC3+ thermogravimetric and simultaneous thermal analyzer, and the results are as follows. Figure 1 .

[0188] Average sandpaper drop resistance height: The sum of the sandpaper drop resistance heights measured from multiple glass samples divided by the number of samples measured is used to characterize the glass's resistance to surface cracking.

[0189] At least 10 samples were taken from each batch for testing, and the average sandpaper drop resistance was measured.

[0190]

[0191] Where n is the number of glass samples tested in each batch, and hi is the drop height of a single sample tested against sandpaper.

[0192] The test method for the sample's resistance to sandpaper drop height is as follows:

[0193] Step 1: Place the glass sample to be tested, with dimensions of 158.8mm × 72.8mm × 0.7mm, onto the front of the 200g model machine;

[0194] Step 2: Place the model on the GreenMap LT-SKDL-CD drop tester, with the glass sample facing the sandpaper, and drop it from a certain height, impacting the 80 / 120 / 180 grit sandpaper located directly below the model to simulate the normal mobile phone drop posture.

[0195] If the glass sample does not break, the drop height of the model machine is increased in a certain pattern. For example, starting from a drop height of 0.4m, the sample is subjected to a drop impact. If it does not break, the height is increased by 0.1m each time and the sample is dropped again until the glass sample breaks.

[0196] Step 3: Record the height of the glass sample when it broke as the sandpaper drop height. For example, if the drop height when it broke was 0.5m, then the sandpaper drop height of the sample is 0.4m.

[0197] The method for preparing the reinforced microcrystalline glass of the present invention includes the following steps:

[0198] (1) Preparation of substrate glass:

[0199] Mix the ingredients according to the formula for 30 minutes, add the clarifying agent, and melt it in a platinum crucible at 1400-1650°C for 5 hours. Then pour it into a molding mold to form it. After cooling to 900°C, place it in an annealing furnace at 450-600°C, preferably 450-550°C, for annealing for 6-240 hours, preferably 6-120 hours. After that, cool it to room temperature with the furnace to obtain the substrate glass.

[0200] The clarifying agent can be any one or more substances selected from NaCl, Sb2O3, As2O3, nitrates, sulfates, etc., and its mass ratio added to the substrate glass raw material is 0.10 to 1.00 wt%, that is, the amount of clarifying agent accounts for 0.10 to 1.00 wt% of the total amount of substrate glass raw material.

[0201] (2) Preparation of glass-ceramics:

[0202] Transparent microcrystalline glass bricks can be prepared by sequentially performing nucleation and crystallization treatments on the substrate glass.

[0203] For nucleation, the temperature is increased to the nucleation temperature (500–700℃) at a rate of 5–20℃ / min, preferably 10℃ / min, and the treatment time is 10–1440 min. For crystallization, the temperature is increased to the crystallization temperature (640–750℃) at a rate of 5–20℃ / min, preferably 10℃ / min, and the treatment time is 5–1440 min. The nucleation time refers to the holding time after the crystallization furnace reaches the set nucleation temperature at the set heating rate. The crystallization time refers to the holding time after the crystallization furnace reaches the set crystallization temperature at the set heating rate.

[0204] (3) Cold processing of samples:

[0205] The microcrystalline glass bricks obtained in step (2) are subjected to cold processing, which includes slicing. Before slicing, the microcrystalline glass bricks can be shaped. After slicing, CNC processing, grinding, and polishing can be performed in sequence. Alternatively, after slicing, at least one of CNC processing, grinding, and polishing can be selected for glass sheet modification to obtain microcrystalline glass samples of the desired size, such as polished sheets with a length, width, and thickness of 50mm×50mm×0.7mm or 158.8mm×72.8mm×0.7mm.

[0206] (4) Chemical fortification:

[0207] The obtained microcrystalline glass sample (i.e., polished sheet) is chemically strengthened in a pure sodium salt or lithium-sodium-potassium mixed salt bath at 380-550°C for 1-24 hours. The sodium ions in the salt bath are provided by any one or more of sodium nitrate, sodium sulfate, and sodium carbonate, the potassium ions are provided by any one of potassium nitrate, potassium sulfate, and potassium carbonate, and the lithium ions are provided by any one or more of lithium nitrate, lithium sulfate, and lithium carbonate. The present invention preferably uses a mixed salt composed of lithium nitrate, sodium nitrate, and potassium nitrate for chemical strengthening treatment.

[0208] In some embodiments, the enhanced salt bath composition of the present invention is 0.1-100 wt% NaNO3 and 0-99.9 wt% KNO3, and 0-10 wt% LiNO3 is added relative to the total weight of the salt bath.

[0209] The following detailed embodiments illustrate the reinforced microcrystalline glass and its preparation method of the present invention.

[0210] Example

[0211] Taking Example 3 as an example, the specific preparation process is as follows:

[0212] According to the composition ratio of substrate glass E shown in Table 1, the total amount of various raw material powders is weighed to 1000g, and then 5g of clarifying agent (NaCl) is added. The mixture is mixed for 30 minutes using a mixer and melted in a platinum crucible at 1650℃ for 5 hours. After that, it is poured into a molding mold and shaped. After cooling to 900℃, it is placed in an annealing furnace at 480℃ for 12 hours. After that, it is cooled to room temperature with the furnace (at a rate of about 5℃ / min) to obtain the substrate glass sample brick. The preparation method of substrate glass in other embodiments is the same as in embodiment 3. The formulation and batching ratio of substrate glass in embodiments 1-6 and comparative examples 1-7 correspond to the batching letters in Table 1, which are specifically described in Tables 2-2 and 2-1.

[0213] The substrate glass was placed in an annealing furnace for nucleation and crystallization treatment. The heating rate was set to 10℃ / min throughout the process, from room temperature to 545℃, and nucleation treatment was performed at 545℃ for 4 hours. Then the temperature was raised to 675℃ and crystallization treatment was performed at 675℃ for 90 minutes. After that, the furnace was cooled to room temperature to obtain microcrystalline glass sample bricks.

[0214] After shaping, slicing, CNC machining, surface grinding, and polishing, microcrystalline glass sample bricks are obtained to obtain microcrystalline glass sample pieces of the desired size, such as polished pieces with dimensions of 50mm×50mm×0.7mm and 158.8mm×72.8mm×0.7mm.

[0215] According to the salt bath ratios shown in Table 2-2, 700g of NaNO3, 300g of KNO3, and 0.3g of LiNO3 (70wt% NaNO3 + 30wt% KNO3 + 0.03wt% LiNO3, where 0.03wt% LiNO3 refers to the mass ratio of additional LiNO3 added relative to the total amount of the mixed salt composed of NaNO3 and KNO3) were weighed and placed in a crucible, and melted into a liquid state in a strengthening furnace at a temperature of 480℃. The resulting polished sheet was placed in the molten salt bath and strengthened at 480℃ for 7 hours, undergoing a single strengthening treatment to obtain a strengthened microcrystalline glass sheet.

[0216] The performance of the obtained reinforced microcrystalline glass sheet was tested. After stress was tested with SLP-2000, a whole-machine drop test was conducted with sandpaper of different grits. The results are shown in Table 2-2.

[0217] Tables 2-1 and 2-2 show the specific conditions for strengthening the glass in Comparative Examples 1-7 and Examples 1-6, including the salt bath mass ratio, salt bath temperature, and salt bath time (Comparative Example 1 underwent two strengthening treatments (the strengthening salt baths used for the first and second strengthening treatments are referred to as "first-strength salt bath" and "second-strength salt bath," respectively), while the other examples and comparative examples underwent only one strengthening treatment). After different strengthening treatments, various stress tests and drop experiments were conducted on the different strengthened glass microcrystal samples obtained. The specific stress test data and drop experiment data are summarized in Tables 2-1 and 2-2, respectively.

[0218] As shown in Comparative Examples 1 to 7 in Table 2-1, when the microcrystalline glass cannot simultaneously satisfy 1.01% ≥ Δα ≥ 0.65%, (CS_50 / DOL_0) ≥ 0.332 × (surface CS / |CT_CV|), and DOL_0 ≥ 0.187t, the average drop height of the entire machine with 80-mesh sandpaper is only between 0.88 and 1.15m.

[0219] As shown in Examples 1 to 6 of Table 2-2, the surface CS of the reinforced microcrystalline glass of the present invention is greater than 270 MPa, within the range of 272-428 MPa; CS_50 is greater than 164 MPa, within the range of 164.44-245.83 MPa; CS_100 is greater than 59.55 MPa, within the range of 59.55-91.81 MPa; |CT_CV| is greater than 113 MPa, specifically within the range of 113.54-145.86 MPa; |CT_AV| is greater than 85 MPa, within the range of 85.49-101.19 MPa; DOL_0 is greater than 130 μm, within the range of 130.60-151.57 μm; CT_LD is greater than 50000 MPa / mm, within the range of 50477.18-60721.55 MPa / mm. The reinforced microcrystalline glass of this invention meets the following characteristics: 1.01% ≥ Δα ≥ 0.65%, (CS_50 / DOL_0) ≥ 0.332 × (surface CS / |CT_CV|), and DOL_0 ≥ 0.187t. In a drop test with 80-grit sandpaper, the average drop height resisted by this reinforced microcrystalline glass can reach over 1.31m. Tables 2-1 and 2-2 show that for the same glass sample, the higher the grit number of the sandpaper, the greater the average drop height. A higher grit number of sandpaper results in smaller coated diamond particles and a shallower puncture depth.

[0220] Furthermore, the present invention Figure 1 This is a DSC diagram of the substrate glass in Example 3 (Glass E composition) of the present invention, heated to 1000°C in nitrogen at a heating rate of 10°C / min. As can be seen from the diagram, the nucleation temperature of the substrate glass of this formulation is between 530°C and 550°C, and the crystallization temperature is between 670°C and 700°C.

[0221] Figure 2 This is a transmittance curve of the microcrystalline glass of Example 3 (glass composition E) tested using a Shimadzu UV-2600 UV-Vis spectrophotometer in the range of 200nm to 1000nm. As can be seen from the graph, the microcrystalline glass of the present invention has high transmittance and good transparency in the visible light wavelength range.

[0222] Figure 3 This is the X-ray diffraction pattern of the microcrystalline glass of Example 3 (glass composition E) of the present invention. As can be seen from the diffraction pattern, the microcrystalline glass of the present invention obtained in Example 3 mainly contains lithium feldspar and lithium disilicate crystalline phases.

[0223] Table 1: Formulation, heat treatment, crystal phase composition and transmittance of glass-ceramics

[0224]

[0225]

[0226] Table 2-1

[0227]

[0228]

[0229] Table 2-2

[0230]

[0231]

[0232]

[0233] Note: Since the drop tester used for drop resistance testing has a test limit of 2.5m, if the glass does not break after the drop test is conducted at the upper limit, it is determined that the average drop resistance of the glass to sandpaper is greater than 2.5m.

Claims

1. A terminal product, characterized in that: The end product includes reinforced microcrystalline glass, which contains lithium feldspar crystal phase and lithium disilicate crystal phase. The reinforced microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface and a tensile stress layer in the interior. The reinforced microcrystalline glass satisfies: DOL_0≥0.187t, where t is the thickness of the reinforced microcrystalline glass; 1.01%≥Δα>0.66%,Δα=5×10 -5 ×|CT_AV|+0.0026; The tensile stress linear density CT_LD is 45000 MPa / mm~90000 MPa / mm; |CT_CV| is 50 MPa ~ 210 MPa; in: CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; DOL_0: Depth of compressive stress layer, in μm.

2. The terminal product according to claim 1, characterized in that: DOL_0≥0.195t.

3. The terminal product according to claim 2, characterized in that: DOL_0≥0.200t.

4. The terminal product according to claim 1, characterized in that: The reinforced microcrystalline glass satisfies: |CT_AV| greater than 80.63 MPa; and / or, |CT_CV| is greater than 113MPa.

5. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass satisfies the following conditions: CS_50 is 100 MPa ~ 400 MPa; and / or, CS_100 is 20 MPa ~ 150 MPa.

6. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_AV| greater than 85MPa; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

7. The terminal product according to claim 6, characterized in that: The reinforced microcrystalline glass satisfies: |CT_AV| is 85.49 MPa -101.19 MPa; and / or, CS_50 is 164.44 MPa -245.83 MPa; and / or, CS_100 is 59.55 MPa -91.81 MPa.

8. The terminal product according to claim 5, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_AV| greater than 85MPa; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

9. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

10. The terminal product according to claim 9, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

472.

11. The terminal product according to claim 10, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

552.

12. The terminal product according to claim 8, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

13. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

14. The terminal product according to claim 13, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is greater than 270 MPa.

15. The terminal product according to claim 14, characterized in that: The reinforced microcrystalline glass meets the following requirements: surface CS is 272 MPa - 428 MPa.

16. The terminal product according to claim 12, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

17. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%.

18. The terminal product according to claim 16, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%.

19. The terminal product according to any one of claims 1-4, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

20. The terminal product according to claim 19, characterized in that: In the reinforced microcrystalline glass, the total content of lithium feldspar crystal phase and lithium disilicate crystal phase is greater than or equal to 79 wt%.

21. The terminal product according to claim 20, characterized in that: The total content of lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is 79wt%~97wt%.

22. The terminal product according to claim 18, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

23. The terminal product according to any one of claims 1-4, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

24. The terminal product according to claim 23, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-30nm.

25. The terminal product according to claim 24, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-20nm.

26. The terminal product according to claim 22, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

27. The terminal product according to any one of claims 1-4, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent.

28. The terminal product according to claim 27, characterized in that: With a thickness of 0.7 mm, the transmittance of the reinforced microcrystalline glass for light with a wavelength of 550 nm is not less than 90.00%.

29. The terminal product according to claim 26, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent.

30. The terminal product according to any one of claims 1-4, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentages of SiO2 are 65.00%~75.00%, Al2O3 are 5.00%~10.00%, P2O5 are 1.00%~5.00%, ZrO2 are 1.00%~10.00%, and Li2O are 5.00%~15.00%.

31. The terminal product according to claim 29, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentages of SiO2 are 65.00%~75.00%, Al2O3 are 5.00%~10.00%, P2O5 are 1.00%~5.00%, ZrO2 are 1.00%~10.00%, and Li2O are 5.00%~15.00%.

32. The terminal product according to claim 30, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains K2O; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains CaO.

33. The terminal product according to claim 32, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~3.00%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.10% to 3.00%.

34. The terminal product according to claim 33, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~0.50%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.50%~1.00%.

35. The terminal product according to claim 34, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.13%~0.37%; and / or, The mass percentage of CaO in the tensile stress layer of the reinforced microcrystalline glass is 0.77~0.98%.

36. The terminal product according to claim 30, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-5.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0-4.00% B2O3 by mass.

37. The terminal product according to claim 36, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-1.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.10% to 1.00% B2O3 by mass.

38. The terminal product according to claim 37, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0.31%~1.00% or 0.06%~0.31% Na₂O by mass percentage; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.21% to 0.91% B2O3 by mass.

39. The terminal product according to claim 32, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-5.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0-4.00% B2O3 by mass.

40. The terminal product according to claim 30, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 68.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~10.00%; and / or, The weight percentage of P2O5 is 1.00%~3.00%; and / or, The weight percentage of ZrO2 is 2.00%~8.00%; and / or, The weight percentage of Li2O is 8.00%~13.00%.

41. The terminal product according to claim 40, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~8.50%; and / or, The weight percentage of P2O5 is 1.50%~3.00%; and / or, The weight percentage of ZrO2 is 5.00%~7.00%; and / or, The weight percentage of Li2O is 9.00%~12.00%.

42. The terminal product according to claim 41, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.06%~71.65%; and / or, The weight percentage of Al2O3 is 7.00%~8.30%; and / or, The weight percentage of P2O5 is 2.00%~2.80%; and / or, The weight percentage of ZrO2 is 5.40%~6.60%; and / or, The weight percentage of Li2O is 10.00%~11.50%.

43. The terminal product according to any one of claims 1-4, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

44. The terminal product according to claim 31, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

45. The terminal product according to any one of claims 1-4, characterized in that: The reinforced microcrystalline glass is used as a protective cover for the end product.

46. ​​The terminal product according to claim 45, characterized in that: The terminal product is a smart terminal product.

47. The terminal product according to claim 46, characterized in that: The terminal products include mobile phones.

48. A reinforced microcrystalline glass, characterized in that: The reinforced microcrystalline glass contains a lithium feldspar crystal phase and a lithium disilicate crystal phase. The reinforced microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface and a tensile stress layer in the interior. The reinforced microcrystalline glass satisfies: DOL_0≥0.187t, where t is the thickness of the reinforced microcrystalline glass; 1.01%≥Δα>0.66%,Δα=5×10 -5 ×|CT_AV|+0.0026; The tensile stress linear density CT_LD is 45000 MPa / mm~90000 MPa / mm; |CT_CV| is 50 MPa ~ 210 MPa; in: CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; DOL_0: Depth of compressive stress layer, in μm.

49. The reinforced microcrystalline glass according to claim 48, characterized in that: DOL_0≥0.195t.

50. The reinforced microcrystalline glass according to claim 49, characterized in that: DOL_0≥0.200t.

51. The reinforced microcrystalline glass according to claim 48, characterized in that: The reinforced microcrystalline glass satisfies: |CT_AV| greater than 80.63 MPa; and / or, |CT_CV| is greater than 113MPa.

52. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The reinforced microcrystalline glass satisfies the following conditions: CS_50 is 100 MPa ~ 400 MPa; and / or, CS_100 is 20 MPa ~ 150 MPa.

53. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_AV| greater than 85MPa; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

54. The reinforced microcrystalline glass according to claim 53, characterized in that: The reinforced microcrystalline glass satisfies: |CT_AV| is 85.49 MPa -101.19 MPa; and / or, CS_50 is 164.44 MPa -245.83 MPa; and / or, CS_100 is 59.55 MPa -91.81 MPa.

55. The reinforced microcrystalline glass according to claim 52, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_AV| greater than 85MPa; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

56. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

57. The reinforced microcrystalline glass according to claim 56, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

472.

58. The reinforced microcrystalline glass according to claim 57, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

552.

59. The reinforced microcrystalline glass according to claim 55, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

60. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

61. The reinforced microcrystalline glass according to claim 60, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is greater than 270 MPa.

62. The reinforced microcrystalline glass according to claim 61, characterized in that: The reinforced microcrystalline glass meets the following requirements: surface CS is 272 MPa - 428 MPa.

63. The reinforced microcrystalline glass according to claim 59, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

64. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%.

65. The reinforced microcrystalline glass according to claim 63, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%.

66. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

67. The reinforced microcrystalline glass according to claim 66, characterized in that: In the reinforced microcrystalline glass, the total content of lithium feldspar crystal phase and lithium disilicate crystal phase is greater than or equal to 79 wt%.

68. The reinforced microcrystalline glass according to claim 67, characterized in that: The total content of lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is 79wt%~97wt%.

69. The reinforced microcrystalline glass according to claim 65, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

70. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

71. The reinforced microcrystalline glass according to claim 70, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-30nm.

72. The reinforced microcrystalline glass according to claim 71, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-20nm.

73. The reinforced microcrystalline glass according to claim 69, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

74. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent.

75. The reinforced microcrystalline glass according to claim 74, characterized in that: With a thickness of 0.7 mm, the transmittance of the reinforced microcrystalline glass for light with a wavelength of 550 nm is not less than 90.00%.

76. The reinforced microcrystalline glass according to claim 73, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent.

77. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentages of SiO2 are 65.00%~75.00%, Al2O3 are 5.00%~10.00%, P2O5 are 1.00%~5.00%, ZrO2 are 1.00%~10.00%, and Li2O are 5.00%~15.00%.

78. The reinforced microcrystalline glass according to claim 76, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentages of SiO2 are 65.00%~75.00%, Al2O3 are 5.00%~10.00%, P2O5 are 1.00%~5.00%, ZrO2 are 1.00%~10.00%, and Li2O are 5.00%~15.00%.

79. The reinforced microcrystalline glass according to claim 77, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains K2O; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains CaO.

80. The reinforced microcrystalline glass according to claim 79, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~3.00%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.10% to 3.00%.

81. The reinforced microcrystalline glass according to claim 80, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~0.50%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.50%~1.00%.

82. The reinforced microcrystalline glass according to claim 81, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.13%~0.37%; and / or, The mass percentage of CaO in the tensile stress layer of the reinforced microcrystalline glass is 0.77~0.98%.

83. The reinforced microcrystalline glass according to claim 77, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-5.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0-4.00% B2O3 by mass.

84. The reinforced microcrystalline glass according to claim 83, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-1.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.10% to 1.00% B2O3 by mass.

85. The reinforced microcrystalline glass according to claim 84, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0.31%~1.00% or 0.06%~0.31% Na₂O by mass percentage; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.21% to 0.91% B2O3 by mass.

86. The reinforced microcrystalline glass according to claim 77, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 68.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~10.00%; and / or, The weight percentage of P2O5 is 1.00%~3.00%; and / or, The weight percentage of ZrO2 is 2.00%~8.00%; and / or, The weight percentage of Li2O is 8.00%~13.00%.

87. The reinforced microcrystalline glass according to claim 86, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~8.50%; and / or, The weight percentage of P2O5 is 1.50%~3.00%; and / or, The weight percentage of ZrO2 is 5.00%~7.00%; and / or, The weight percentage of Li2O is 9.00%~12.00%.

88. The reinforced microcrystalline glass according to claim 87, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.06%~71.65%; and / or, The weight percentage of Al2O3 is 7.00%~8.30%; and / or, The weight percentage of P2O5 is 2.00%~2.80%; and / or, The weight percentage of ZrO2 is 5.40%~6.60%; and / or, The weight percentage of Li2O is 10.00%~11.50%.

89. The reinforced microcrystalline glass according to any one of claims 48-51, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

90. The reinforced microcrystalline glass according to claim 78, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

91. A reinforced microcrystalline glass, characterized in that: The reinforced microcrystalline glass contains a lithium feldspar crystal phase and a lithium disilicate crystal phase. The reinforced microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface and a tensile stress layer in the interior. The reinforced microcrystalline glass satisfies: DOL_0≥0.187t, where t is the thickness of the reinforced microcrystalline glass; The tensile stress linear density CT_LD is 45000 MPa / mm~90000 MPa / mm; |CT_CV| is 50 MPa ~ 210 MPa; |CT_AV| is greater than 85MPa; in: CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; DOL_0: Depth of compressive stress layer, in μm.

92. The reinforced microcrystalline glass according to claim 91, characterized in that: DOL_0≥0.195t.

93. The reinforced microcrystalline glass according to claim 91, characterized in that: DOL_0≥0.200t.

94. The reinforced microcrystalline glass according to claim 91, characterized in that: The reinforced microcrystalline glass satisfies: |CT_CV| is greater than 113 MPa; where CT_CV is the maximum tensile stress in the tensile stress layer, in MPa.

95. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The reinforced microcrystalline glass satisfies the following conditions: CS_50 is 100 MPa ~ 400 MPa; and / or, CS_100 is 20 MPa ~ 150 MPa.

96. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

97. The reinforced microcrystalline glass according to claim 96, characterized in that: The reinforced microcrystalline glass satisfies: CS_50 is 164.44 MPa -245.83 MPa; and / or, CS_100 is 59.55 MPa -91.81 MPa.

98. The reinforced microcrystalline glass according to claim 95, characterized in that: The reinforced microcrystalline glass satisfies: CT_LD greater than 50000MPa / mm; and / or, |CT_CV| is 113.54MPa-145.86MPa; and / or, CS_50 is greater than 164MPa; and / or, CS_100 is greater than 59.55 MPa.

99. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

100. The reinforced microcrystalline glass according to claim 99, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

472.

101. The reinforced microcrystalline glass according to claim 100, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0) / (surface CS / |CT_CV|)≥0.

552.

102. The reinforced microcrystalline glass according to claim 98, characterized in that: The reinforced microcrystalline glass satisfies: (CS_50 / DOL_0)≥0.332×(surface CS / |CT_CV|); in: Surface CS: Surface compressive stress, in MPa; CS_50: Compressive stress at a depth of 50 μm from the glass surface, in MPa; CT_AV: Average tensile stress in the tensile stress layer, in MPa; CT_CV: Maximum tensile stress in the tensile stress layer, in MPa; and DOL_0: Depth of compressive stress layer, in μm.

103. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

104. The reinforced microcrystalline glass according to claim 103, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is greater than 270 MPa.

105. The reinforced microcrystalline glass according to claim 104, characterized in that: The reinforced microcrystalline glass meets the following requirements: surface CS is 272 MPa - 428 MPa.

106. The reinforced microcrystalline glass according to claim 102, characterized in that: The reinforced microcrystalline glass satisfies the following condition: surface CS is 200~680MPa.

107. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%, Δα=5×10 -5 ×|CT_AV|+0.0026; where: CT_AV: Average tensile stress in the tensile stress layer, in MPa.

108. The reinforced microcrystalline glass according to claim 107, characterized in that: The reinforced microcrystalline glass satisfies: |CT_AV| is 85.49 MPa -101.19 MPa.

109. The reinforced microcrystalline glass according to claim 106, characterized in that: The reinforced microcrystalline glass satisfies: 1.01%≥Δα≥0.69%, Δα=5×10 -5 ×|CT_AV|+0.0026; where: CT_AV: Average tensile stress in the tensile stress layer, in MPa.

110. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

111. The reinforced microcrystalline glass according to claim 110, characterized in that: In the reinforced microcrystalline glass, the total content of lithium feldspar crystal phase and lithium disilicate crystal phase is greater than or equal to 79 wt%.

112. The reinforced microcrystalline glass according to claim 111, characterized in that: The total content of lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is 79wt%~97wt%.

113. The reinforced microcrystalline glass according to claim 109, characterized in that: The total content of the lithium feldspar crystal phase and lithium disilicate crystal phase in the reinforced microcrystalline glass is above 75 wt%.

114. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

115. The reinforced microcrystalline glass according to claim 114, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-30nm.

116. The reinforced microcrystalline glass according to claim 115, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-20nm.

117. The reinforced microcrystalline glass according to claim 113, characterized in that: In the reinforced microcrystalline glass, the average size of the grains is 10nm-50nm.

118. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent to light with a wavelength of 550 nm.

119. The reinforced microcrystalline glass according to claim 118, characterized in that: With a thickness of 0.7 mm, the transmittance of the reinforced microcrystalline glass for light with a wavelength of 550 nm is not less than 90.00%.

120. The reinforced microcrystalline glass according to claim 117, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass is transparent to light with a wavelength of 550 nm.

121. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: the weight percentage of SiO2 is 65.00%~75.00%, the weight percentage of Al2O3 is 5.00%~10.00%, the weight percentage of P2O5 is 1.00%~5.00%, the weight percentage of ZrO2 is 1.00%~10.00%, and the weight percentage of Li2O is 5.00%~15.00%.

122. The reinforced microcrystalline glass according to claim 120, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: the weight percentage of SiO2 is 65.00%~75.00%, the weight percentage of Al2O3 is 5.00%~10.00%, the weight percentage of P2O5 is 1.00%~5.00%, the weight percentage of ZrO2 is 1.00%~10.00%, and the weight percentage of Li2O is 5.00%~15.00%.

123. The reinforced microcrystalline glass according to claim 121, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains K2O; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains CaO.

124. The reinforced microcrystalline glass according to claim 123, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~3.00%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.10% to 3.00%.

125. The reinforced microcrystalline glass according to claim 124, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.10%~0.50%; and / or, In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of CaO is 0.50%~1.00%.

126. The reinforced microcrystalline glass according to claim 125, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass, the mass percentage of K2O is 0.13%~0.37%; and / or, The mass percentage of CaO in the tensile stress layer of the reinforced microcrystalline glass is 0.77~0.98%.

127. The reinforced microcrystalline glass according to claim 121, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-5.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0-4.00% B2O3 by mass.

128. The reinforced microcrystalline glass according to claim 127, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0-1.00% Na₂O by mass; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.10% to 1.00% B2O3 by mass.

129. The reinforced microcrystalline glass according to claim 128, characterized in that: The tensile stress layer of the reinforced microcrystalline glass also contains 0.31%~1.00% or 0.06%~0.31% Na₂O by mass percentage; and / or, The tensile stress layer of the reinforced microcrystalline glass also contains 0.21% to 0.91% B2O3 by mass.

130. The reinforced microcrystalline glass according to claim 121, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 68.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~10.00%; and / or, The weight percentage of P2O5 is 1.00%~3.00%; and / or, The weight percentage of ZrO2 is 2.00%~8.00%; and / or, The weight percentage of Li2O is 8.00%~13.00%.

131. The reinforced microcrystalline glass according to claim 130, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.00%~72.00%; and / or, The weight percentage of Al2O3 is 6.00%~8.50%; and / or, The weight percentage of P2O5 is 1.50%~3.00%; and / or, The weight percentage of ZrO2 is 5.00%~7.00%; and / or, The weight percentage of Li2O is 9.00%~12.00%.

132. The reinforced microcrystalline glass according to claim 131, characterized in that: In the tensile stress layer of the reinforced microcrystalline glass: The weight percentage of SiO2 is 70.06%~71.65%; and / or, The weight percentage of Al2O3 is 7.00%~8.30%; and / or, The weight percentage of P2O5 is 2.00%~2.80%; and / or, The weight percentage of ZrO2 is 5.40%~6.60%; and / or, The weight percentage of Li2O is 10.00%~11.50%.

133. The reinforced microcrystalline glass according to any one of claims 91-94, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

134. The reinforced microcrystalline glass according to claim 122, characterized in that: At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 80-grit sandpaper. The average drop height resistance of the reinforced microcrystalline glass was 1.30~1.80 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.00 m; and / or, At a thickness of 0.7 mm, the reinforced microcrystalline glass was subjected to a sandpaper drop test using 180-grit sandpaper. The average sandpaper drop height resisted by the reinforced microcrystalline glass was greater than 2.50 m.

135. A terminal product, characterized in that, The end product includes reinforced microcrystalline glass as described in any one of claims 91-134.

136. The terminal product according to claim 135, characterized in that, Reinforced microcrystalline glass is used as a protective cover for end products.

137. The terminal product according to claim 136, characterized in that, The terminal product is a smart terminal product.

138. The terminal product according to claim 137, characterized in that, The terminal products include mobile phones.

139. A cover plate for use in mobile devices or terminal products, characterized in that, The cover plate comprises reinforced microcrystalline glass as described in any one of claims 48-90 or as described in any one of claims 91-134.

140. A mobile device, characterized in that, The mobile device comprises reinforced microcrystalline glass as claimed in any one of claims 48-90 or comprises reinforced microcrystalline glass as claimed in any one of claims 91-134.

141. The mobile device according to claim 140, characterized in that, The reinforced microcrystalline glass serves as a protective cover in mobile devices.

142. The method for preparing the reinforced microcrystalline glass according to any one of claims 48-90 or according to any one of claims 91-134, characterized in that, The process includes the following steps: (1) Preparation of substrate glass: After mixing the various substances of glass raw materials, a clarifying agent is added, the mixture is melted and annealed to obtain substrate glass; (2) Preparation of glass-ceramics: The substrate glass obtained in step (1) is subjected to nucleation and crystallization treatments to obtain glass-ceramics; (3) The microcrystalline glass obtained in step (2) is cold-processed to obtain a polished sheet; and (4) The polished sheet obtained in step (3) is chemically strengthened to obtain reinforced microcrystalline glass.

143. The preparation method according to claim 142, wherein, In process (1), the annealing temperature is 450~600℃ and the annealing time is 6~240 hours.

144. The preparation method according to claim 143, wherein, In process (1), the annealing temperature is 450-550°C and the annealing time is 6-120 hours.

145. The preparation method according to any one of claims 142-144, wherein, In process (2), the nucleation temperature is 500-700℃ and the nucleation time is 10-1440 min.

146. The preparation method according to claim 145, wherein, In process (2), the nucleation temperature is 540-570℃.

147. The preparation method according to any one of claims 142-144, wherein, In step (2), when performing nucleation treatment, the temperature is increased to the nucleation temperature at a heating rate of 5 to 20 °C / min.

148. The preparation method according to claim 147, wherein, In step (2), when performing nucleation, the temperature is increased to the nucleation temperature at a rate of 10℃ / min.

149. The preparation method according to any one of claims 142-144, wherein, In process (2), the crystallization temperature is 640-750℃ and the crystallization time is 5-1440 min.

150. The preparation method according to claim 149, wherein, In process (2), the crystallization temperature is 660-740℃.

151. The preparation method according to claim 150, wherein, In process (2), the crystallization temperature is 670-740℃.

152. The preparation method according to any one of claims 142-144, wherein, In step (2), when crystallization is performed, the temperature is increased to the crystallization temperature at a heating rate of 5 to 20 °C / min.

153. The preparation method according to claim 152, wherein, In step (2), when crystallization is performed, the temperature is increased to the crystallization temperature at a rate of 10℃ / min.

154. The preparation method according to any one of claims 142-144, wherein, In step (4), the polished sheet obtained in step (3) is chemically strengthened in a pure sodium salt or lithium sodium potassium mixed salt bath at 380-550°C.

155. The preparation method according to claim 154, wherein, In process (4), the strengthening time is 1~24h.

156. The preparation method according to claim 154, wherein, In step (4), the sodium ions in the salt bath are provided by any one or more of sodium nitrate, sodium sulfate and sodium carbonate, the potassium ions are provided by any one or more of potassium nitrate, potassium sulfate and potassium carbonate, and the lithium ions are provided by any one or more of lithium nitrate, lithium sulfate and lithium carbonate.

157. The preparation method according to claim 154, wherein, The composition of the lithium-sodium-potassium mixed salt bath is as follows: by mass ratio, it contains 0.1~100wt% NaNO3 and 0~99.9wt% KNO3, and by mass ratio, it contains 0~10wt% LiNO3.

158. The preparation method according to claim 157, wherein, The composition of the lithium-sodium-potassium mixed salt bath is as follows: by mass ratio, it contains 30-95 wt% NaNO3 and 5-70 wt% KNO3, and by mass ratio, it contains 0.01-1 wt% LiNO3 relative to the total mass of NaNO3 and KNO3.

159. The preparation method according to any one of claims 142-144, wherein the chemical strengthening treatment in step (4) is performed 1 to 3 times.

160. The preparation method according to any one of claims 142-144, wherein in step (1), the clarifying agent is selected from any one or more substances selected from NaCl, Sb2O3, As2O3, nitrates, and sulfates; and / or In process (1), the material is melt-formed at 1400-1650°C.

161. According to the preparation method of claim 160, in step (1), the amount of clarifying agent is 0.10-1.00 wt% of the total amount of substrate glass raw material.

162. According to the preparation method of claim 161, in step (1), the amount of clarifying agent is 0.50-1.00 wt% of the total amount of substrate glass raw material.

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