Reinforced sodium nepheline microcrystalline glass and preparation method and application thereof

Abstract

The invention discloses strengthened sodium nepheline glass ceramics as well as a preparation method and application thereof, and belongs to the technical field of glass ceramics. The crystal form of the strengthened sodium nepheline microcrystalline glass is sodium nepheline, and the average crystal size range is 40-55 nm; the strengthened Natryptite microcrystalline glass comprises SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5, and the ratio of (1.5 Na2O + 2.3 K2O + 1.6 Li2O) / (3.4 B2O3) is larger than or equal to 2.32 and smaller than or equal to 4.47 according to the molar percentage of SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5. The stress intensity CS-30 of the strengthened sodium nepheline microcrystalline glass is greater than or equal to 174 MPa. The strengthened Natryptite microcrystalline glass provided by the invention not only can obtain visible light transmittance greater than 90%, but also can improve the chemical strengthening effect and obtain better mechanical properties, and can meet the application requirements in the fields of display equipment or electronic equipment and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of glass-ceramics, and particularly relates to a strengthened nepheline glass-ceramics and its preparation method and application. Background Art

[0002] With the popularization of 5G signals and the widespread use of wireless charging technology, the trend of removing metals from smart phones has become increasingly obvious. Since Corning launched "Ultra Ceramic Crystal", using glass-ceramics as mobile phone covers has become a popular research direction. In addition to excellent mechanical properties to meet requirements such as anti-drop and scratch resistance during use, glass or glass-ceramics are also required to have a high visible light transmittance to improve the user experience comfort.

[0003] Up to now, the crystals mainly included in the transparent glass-ceramics for preparing cover glass are: β-quartz solid solution, β-spodumene, nepheline, spinel, cordierite, etc. The systems in which they are distributed mainly include lithium aluminosilicate system, sodium aluminosilicate system and magnesium aluminosilicate system. Currently, the glass-ceramic mobile phone covers used in the market are mainly lithium aluminosilicate system. With the development of the new energy industry, the price of lithium raw materials has skyrocketed, resulting in a substantial increase in production costs.

[0004] In view of the high price caused by the shortage and tension of lithium resources, the development of low-cost transparent glass-ceramics with less lithium (or without lithium) has become more and more urgent. Therefore, in recent years, nepheline-based glass-ceramics in the sodium aluminosilicate system have become one of the key research objects of many researchers.

[0005] However, there are problems in the existing preparation of nepheline (NaAlSiO4) glass-ceramics that the glass is not easily chemically strengthened, or the mechanical properties of the glass-ceramics are poor after chemical strengthening.

[0006] Therefore, there are deficiencies in the existing technology and it needs to be improved. Summary of the Invention

[0007] The main purpose of the present invention is to provide a strengthened nepheline glass-ceramics and its preparation method and application, so as to solve the technical problems that the existing process for preparing nepheline glass-ceramics is not easily chemically strengthened and the mechanical properties of the strengthened nepheline glass-ceramics obtained after chemical strengthening are not good.

[0008] To achieve the above purpose, the present invention provides a strengthened nepheline glass-ceramics, and the average crystal size range of the strengthened nepheline glass-ceramics is 40nm - 55nm;

[0009] The composition of the strengthened nepheline microcrystalline glass includes SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5, and calculated by mole percentage, it satisfies 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47;

[0010] The stress intensity CS-30 of the strengthened nepheline microcrystalline glass is ≥ 174 MPa, and the CS-30 refers to the compressive stress value of the strengthened nepheline microcrystalline glass at a depth of 30 microns.

[0011] In some embodiments of the present invention, calculated by mole percentage, the strengthened nepheline microcrystalline glass includes components: SiO2: 45.1% - 49.9%, Al2O3: 15% - 17.5%, Na2O: 14% - 16.5%, K2O: 0.5% - 1.6%, Li2O: 7% - 9.6%, B2O3: 2.5% - 4.5%, ZnO: 2.5% - 4.9%, TiO2: 0 - 1.2%, ZrO2: 1.4% - 2.8%, P2O5: 1.8% - 4%.

[0012] In some embodiments of the present invention, the stress intensity CS-30 of the strengthened nepheline microcrystalline glass is 174 MPa - 213 MPa.

[0013] In some embodiments of the present invention, the visible light transmittance of the strengthened nepheline microcrystalline glass > 90%.

[0014] In some embodiments of the present invention, when the thickness of the strengthened nepheline microcrystalline glass is 0.6 mm:

[0015] The stress depth DOL-Na of the strengthened nepheline microcrystalline glass is 134 μm - 148 μm;

[0016] And / or, under the test conditions of 80-mesh sandpaper, the whole machine drop height of the strengthened nepheline microcrystalline glass is 0.9 m - 1.25 m;

[0017] And / or, the scratch resistance critical load of the strengthened nepheline microcrystalline glass is 4 N - 5 N.

[0018] The present invention also provides a preparation method of the strengthened nepheline microcrystalline glass as described above, including the following steps:

[0019] Weigh the glass raw materials according to the composition of the strengthened nepheline microcrystalline glass, and the glass raw materials are heated, melted, homogenized, formed and annealed to obtain the base glass;

[0020] The base glass is heat-treated to obtain the nepheline microcrystalline glass;

[0021] The nepheline microcrystalline glass is chemically strengthened to obtain the strengthened nepheline microcrystalline glass.

[0022] In some embodiments of the present invention, the glass raw materials include the following components:

[0023] SiO2: 45.1% - 49.9%,

[0024] Al2O3: 15% - 17.5%,

[0025] Na2O: 14% - 16.5%,

[0026] K2O: 0.5% - 1.6%,

[0027] Li2O: 7% - 9.6%,

[0028] B2O3: 2.5% - 4.5%,

[0029] ZnO: 2.5% - 4.9%,

[0030] TiO2: 0 - 1.2%,

[0031] ZrO2: 1.4% - 2.8%,

[0032] P2O5: 1.8% - 4%.

[0033] In some embodiments of the present invention, the chemical strengthening includes a first molten salt and a second molten salt. The nepheline microcrystalline glass is subjected to a first chemical strengthening treatment in the first molten salt to obtain a first strengthened microcrystalline glass, and the first strengthened microcrystalline glass is subjected to a second chemical strengthening treatment in the second molten salt to obtain the strengthened nepheline microcrystalline glass.

[0034] In some embodiments of the present invention, the first molten salt includes a sodium salt with a mass concentration of 100%;

[0035] And / or, the second molten salt includes a potassium salt with a mass concentration of 100%.

[0036] In some embodiments of the present invention, the first molten salt includes a sodium salt, and the sodium salt includes sodium nitrate;

[0037] And / or, the second molten salt includes a potassium salt, and the potassium salt includes potassium nitrate.

[0038] In some embodiments of the present invention, the temperature of the first chemical strengthening treatment is 450°C - 460°C, and the heat preservation time is 150 min - 210 min;

[0039] In some embodiments of the present invention, the temperature of the second chemical strengthening treatment is 440°C to 430°C, and the heat preservation time is 90 min to 120 min.

[0040] The present invention also provides an application of the strengthened nepheline microcrystalline glass as described above.

[0041] The beneficial effects that the present invention can achieve:

[0042] The crystal form of the strengthened nepheline microcrystalline glass of the present invention includes nepheline (NaAlSiO4), the average crystal size ranges from 40 nm to 55 nm. Calculated by mole percentage, the components contain SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5, and 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47 is controlled. The obtained stress intensity CS-30 is 174 MPa to 213 MPa. It can not only make the strengthened nepheline microcrystalline glass obtain a visible light transmittance of more than 90%, but also improve the chemical strengthening effect of the glass, make the glass easier to perform efficient ion exchange strengthening, and the depth of the ion exchange layer is larger, so that the strengthened nepheline microcrystalline glass obtained after the glass is chemically strengthened has better mechanical properties.

[0043] The strengthened nepheline microcrystalline glass of the present invention has excellent anti-drop performance and anti-scratch resistance, and high visible light transmittance, which can meet the application requirements in the fields of display devices or electronic devices, etc. For example, it can meet the performance requirements of mobile phones for cover glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0045] Figure 1 It is the DSC diagram of Example 18 of the present invention;

[0046] Figure 2 It is the DSC diagram of Comparative Example 2 of the present invention;

[0047] Figure 3 It is the DSC diagram of Comparative Example 3 of the present invention;

[0048] Figure 4 It is the high-temperature viscosity curve diagram of Example 4 of the present invention;

[0049] Figure 5High-temperature viscosity curve graph of Comparative Example 2 of the present invention;

[0050] Figure 6 XRD graph of Example 11 of the present invention;

[0051] Figure 7 SEM graph of Example 13 of the present invention. Detailed implementation manners

[0052] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0054] In the present invention, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0055] When preparing the strengthened nepheline microcrystalline glass, there are technical problems that the chemical strengthening effect of the glass is not ideal and the mechanical properties of the glass are poor after chemical strengthening.

[0056] In view of this, the present invention provides a strengthened nepheline microcrystalline glass, the average crystal size range of the strengthened nepheline microcrystalline glass is 40nm to 55nm; the composition of the strengthened nepheline microcrystalline glass includes SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5, calculated by mole percentage, satisfying 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47; the stress intensity CS-30 of the strengthened nepheline microcrystalline glass is ≥ 174 MPa, and CS-30 refers to the compressive stress value of the strengthened nepheline microcrystalline glass at a depth of 30 microns.

[0057] In glass-ceramics, when the glass-ceramics include multiple types of crystals, due to the slight differences in refractive indices between various crystals, it is easy to cause a decrease in the light transmittance of the glass-ceramics, and it is difficult to obtain a visible light transmittance of >90%. In the present invention, the crystal form of the strengthened nepheline glass-ceramics is a single crystal form of nepheline (NaAlSiO4), and other crystal forms can be ignored. It can be understood that other crystal forms refer to crystal forms that are not intentionally controlled to be generated in the present invention. Thus, the problem of poor visible light transmittance caused by the slight differences in refractive indices between multiple crystals can be reduced.

[0058] The average crystal size range of the strengthened nepheline glass-ceramics of the present invention is 40 nm to 55 nm, and it can be 40 nm, 42 nm, 43 nm, 45 nm, 48 nm, 50 nm, 52 nm, 54 nm, 55 nm, etc. The crystal particle size is appropriately uniform, which is beneficial to obtaining better light transmittance.

[0059] The composition of the strengthened nepheline glass-ceramics of the present invention includes SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2, and P2O5. Calculated according to mole percentage, it is controlled that 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47. That is, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) can be any value in 2.32 to 4.47, such as 2.32, 2.35, 2.38, 2.40, 2.50, 2.52, 2.55, 2.60, 2.70, 2.80, 2.90, 3.0, 3.2, 3.5, 3.8, 4.0, 4.10, 4.15, 4.20, 4.25, 4.30, 4.35, 4.40, 4.42, 4.45, 4.47, etc. This can not only enable the nepheline glass-ceramics to obtain a visible light transmittance of greater than 90%, but also improve the chemical strengthening effect of the glass, make the glass easier to perform efficient ion-exchange strengthening, and the depth of the ion-exchange layer is relatively large, so that the strengthened nepheline glass-ceramics obtained after chemical strengthening of the glass have better mechanical properties.

[0060] In some embodiments, the visible light transmittance of the strengthened nepheline glass-ceramics is >90%, and the light transmittance is relatively high, which is suitable for the fields of display screen devices and electronic devices. For example, it is used to prepare the cover glass of mobile phones.

[0061] In some embodiments, the visible light transmittance of the strengthened nepheline syenite glass-ceramics is 90.11% to 91.19%. For example, it can be 90.11%, 90.12%, 90.15%, 90.20%, 90.25%, 90.30%, 90.35%, 90.40%, 90.45%, 90.50%, 90.55%, 90.60%, 90.65%, 90.70%, 90.75%, 90.80%, 90.85%, 90.90%, 90.95%, 91.00%, 91.10%, 91.15%, 91.19%, etc.

[0062] In some embodiments, the stress intensity CS-30 of the strengthened nepheline syenite glass-ceramics is ≥174 MPa. When the thickness of the strengthened nepheline syenite glass-ceramics is 0.6 mm, the stress intensity CS-30 of the strengthened nepheline syenite glass-ceramics is 174 MPa to 213 MPa. For example, it can be 174 MPa, 180 MPa, 182 MPa, 185 MPa, 188 MPa, 190 MPa, 192 MPa, 195 MPa, 197 MPa, 198 MPa, 200 MPa, 202 MPa, 205 MPa, 208 MPa, 210 MPa, 211 MPa, 213 MPa, etc.

[0063] The stress intensity CS-30 refers to the stress value at a depth of 30 μm below the surface of the strengthened nepheline syenite glass-ceramics.

[0064] In some embodiments, when the thickness of the strengthened nepheline syenite glass-ceramics is 0.6 mm, the stress depth DOL-Na of the strengthened nepheline syenite glass-ceramics is 134 μm to 148 μm. It can be 134 μm, 138 μm, 140 μm, 142 μm, 144 μm, 145 μm, 146 μm, 147 μm, 148 μm, etc.

[0065] The stress depth DOL-Na refers to the + exchange depth of Na + and Li, and also represents the strengthening glass pressure depth.

[0066] In some embodiments, when the thickness of the strengthened nepheline syenite glass-ceramics is 0.6 mm, under the test conditions of 80-mesh sandpaper, the overall machine drop height of the strengthened nepheline syenite glass-ceramics is 0.9 m to 1.25 m. It can be 0.9 m, 0.95 m, 1 m, 1.1 m, 1.2 m, 1.21 m, 1.23 m, 1.24 m, 1.25 m, etc.

[0067] In some embodiments, when the thickness of the strengthened nepheline syenite glass-ceramics is 0.6 mm, the scratch resistance critical load of the strengthened nepheline syenite glass-ceramics is 4 N to 5 N.

[0068] The strengthened nepheline syenite glass-ceramics of the present invention have excellent anti-drop and anti-scratch properties, and high visible light transmittance, which can meet the application requirements in the fields of display devices or electronic devices, etc. For example, they can meet the performance requirements of mobile phones for cover glass.

[0069] The present invention also provides a method for preparing strengthened nepheline syenite glass-ceramics, which includes the following steps:

[0070] S10. Weigh glass raw materials according to the composition of nepheline syenite glass-ceramics. The glass raw materials are heated, melted, homogenized, formed, and annealed to obtain a base glass;

[0071] S20. The base glass is heat-treated to obtain nepheline syenite glass-ceramics;

[0072] S30. The nepheline syenite glass-ceramics are chemically strengthened to obtain strengthened nepheline syenite glass-ceramics.

[0073] In the present invention, after the treatments of steps S10 and S20, the composition of the glass-ceramics has been basically determined. The main purpose of the subsequent chemical strengthening in step S30 is to improve its mechanical properties and obtain strengthened nepheline syenite glass-ceramics.

[0074] In some embodiments, calculated by mole percentage, the glass raw materials of the strengthened nepheline syenite glass-ceramics include the following components: SiO2: 45.1% - 49.9%, Al2O3: 15% - 17.5%, Na2O: 14% - 16.5%, K2O: 0.5% - 1.6%, Li2O: 7% - 9.6%, B2O3: 2.5% - 4.5%, ZnO: 2.5% - 4.9%, TiO2: 0 - 1.2%, ZrO2: 1.4% - 2.8%, P2O5: 1.8% - 4%.

[0075] SiO2 is the core material that constitutes the glass network. In the glass, it forms an irregular continuous network with the structural unit of silicon-oxygen tetrahedron [SiO4], which becomes the skeleton of the glass structure and is one of the components that form the sodium nepheline crystal phase after crystallization. SiO2 can increase the melting temperature, high-temperature viscosity, chemical stability, thermal stability and mechanical strength of the glass. Therefore, if the content of SiO2 is too little, the main network structure of the glass is poor, the mechanical properties are poor, and the chemical stability becomes poor. However, if the content of SiO2 is too much, the melting temperature will increase accordingly, and too high a melting temperature will increase the process cost and energy consumption. In addition, the proportion of the glass silicon-oxygen skeleton structure is high at this time, and the network gap is small, which is not conducive to the subsequent chemical strengthening ion exchange and affects the efficiency of chemical strengthening. In some embodiments, the preferred content of SiO2 is 45.1% to 49.9%, and can be 45.1%, 45.2%, 45.3%, 45.4%, 45.5%, 45.6%, 45.8%, 45.9%, 46%, 46.5%, 47%, 47.5%, 48%, 48.5%, 49%, 49.5%, 49.6%, 49.7%, 49.8%, 49.9% or any value in the range of 45.1% to 49.9%, which can better balance the chemical stability, thermal stability and mechanical strength of the glass, while avoiding the cost increase caused by too high melting temperature and the problem of subsequent chemical strengthening ion exchange caused by the high proportion of the silicon oxygen skeleton structure of the glass and the small network gap.

[0076] Al2O3 is a glass intermediate oxide, which can improve the chemical stability and mechanical strength of glass. It is also a necessary component to increase the ion exchange capacity of glass, and is also one of the components that form the sodium nepheline crystal phase after crystallization. If the content of Al2O3 is too little, the physical properties of the glass deteriorate, the sodium nepheline crystal phase formation ability deteriorates, and the gaps in the glass network space become smaller, which is not conducive to ion migration and seriously affects the efficiency of chemical strengthening. If the content of Al2O3 is too much, the melting temperature is too high and the production cost is greatly improved. In some embodiments, the preferred content of Al2O3 is 15% to 17.5%, which can be any value in the range of 15%, 15.3%, 15.5%, 15.8%, 15.9%, 16%, 16.2%, 16.5%, 16.7%, 16.9%, 17%, 17.1%, 17.2%, 17.3%, 17.4%, 17.5%, etc. 15% to 17.5%.

[0077] Na2O is an external oxide of the glass network, which can reduce the high-temperature viscosity of the glass. It is an essential component for ion exchange in the glass and is also one of the components that form the nepheline crystal phase after crystallization. If the content of Na2O is too low, the melting temperature of the glass decreases insignificantly, and the ion exchange ability and the ability to form the nepheline crystal phase become poor. If the content of Na2O is too high, the chemical stability and mechanical strength of the glass decrease, and during the glass crystallization process, it promotes the abnormal rapid growth of crystals, resulting in a decrease in the glass transmittance and even devitrification. In some embodiments, the content of Na2O is 14% to 16.5%, and can be any value in the range of 14% to 16.5% such as 14%, 14.1%, 14.3%, 14.5%, 14.8%, 14.9%, 15%, 15.2%, 15.3%, 15.5%, 15.6%, 15.8%, 15.9%, 16%, 16.1%, 16.2%, 6.3%, 16.4%, 16.5%.

[0078] K2O is an external oxide of the glass network, which can reduce the high-temperature viscosity of the glass. The introduction of K2O can utilize the "mixed alkali effect" of the glass to adjust the melting properties and mechanical strength of the glass. Since K2O in the glass does not participate in ion exchange, its content is limited. In some embodiments, the preferred content of K2O is 0.5% to 1.6%, and can be any value in the range of 0.5% to 1.6% such as 0.5%, 0.6%, 0.7%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%.

[0079] Li2O is an external oxide of the glass network, which can reduce the high-temperature viscosity of the glass. It is an essential component for ion exchange in the glass, especially for the two-step ion exchange. If the content of Li2O is too low, the ion exchange ability of the glass is greatly weakened. If the content of Li2O is too high, the chemical stability and mechanical strength of the glass decrease, and the manufacturing cost of the glass increases significantly. The preferred content of Li2O is 7% to 9.6%, and can be any value in the range of 7% to 9.6% such as 7%, 7.2%, 7.5%, 7.6%, 7.8%, 7.9%, 8%, 8.1%, 8.3%, 8.5%, 8.7%, 8.9%, 9%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%.

[0080] B2O3 is an important glass - forming oxide, which can lower the melting temperature, improve the mechanical strength, toughness and chemical stability of the glass. If the content of B2O3 is too small, the above - mentioned effects cannot be obtained. If the content of B2O3 is too large, the glass is prone to phase separation, and at the same time, it will hinder the ion - exchange process during chemical strengthening. In some embodiments, the preferred content of B2O3 is 2.5% - 4.5%, and it can be any value in the range of 2.5% - 4.5% such as 2.5%, 2.6%, 2.8%, 3%, 3.1%, 3.2%, 3.5%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%.

[0081] ZnO is an external glass - network oxide, which can improve the glass - forming property of the base glass, increase the crystallization tendency of the glass, and lower the glass melting temperature. However, too high a content is not conducive to the formation of the glass and is prone to cause phase separation of the glass. In some embodiments, the preferred content of ZnO is 2.5% - 4.9%, and it can be any value in the range of 2.5% - 4.9% such as 2.5%, 2.6%, 2.8%, 3%, 3.2%, 3.5%, 3.7%, 3.9%, 4%, 4.1%, 4.3%, 4.5%, 4.8%, 4.9%.

[0082] TiO2 is a nucleating agent. The introduction of TiO2 effectively promotes the precipitation of crystal nuclei during the nucleation process. Excessive introduction of TiO2 is likely to cause phase separation of the melt, resulting in crystallization and affecting the formation of the glass; and it will color the glass, resulting in a decrease in transmittance and a yellowish color. In some embodiments, the preferred content of TiO2 is 0 - 1.2%, and it can be not added, or 0.1%, 0.3%, 0.5%, 0.8%, 0.9%, 1%, 1.1%, 1.2% etc. can be added.

[0083] ZrO2 is a nucleating agent. The introduction of ZrO2 can not only effectively promote crystal nuclei, but also play a role in refining the crystal grains, promoting the precipitation of nanoscale crystals in the glass - ceramic, and is also beneficial to improving the chemical stability of the glass. However, too high an introduction amount of ZrO2 will cause difficult melting, and the glass melt is prone to crystallization, affecting the forming process. In some embodiments, the preferred content of ZrO2 is 1.4% - 2.8%, and it can be any value in the range of 1.4% - 2.8% such as 1.4%, 1.5%, 1.8%, 2%, 2.1%, 2.3%, 2.5%, 2.7%, 2.8%, 2.9% etc.

[0084] P2O5 is a nucleating agent. P2O5 can form crystal nuclei in the glass, promote the uniform growth of crystals, and help improve the low-temperature fusibility of the glass. However, if the glass contains too much P2O5, it is very easy to cause devitrification and phase separation of the glass. In some embodiments, the preferred content of P2O5 is 1.8% to 4%, and it can be any value in the range of 1.8% to 4% such as 1.8%, 1.9%, 2%, 2.3%, 2.5%, 2.7%, 2.8%, 2.9%, 3%, 3.2%, 3.5%, 3.7%, 3.8%, 3.9%, 4%.

[0085] The strengthened nepheline microcrystalline glass prepared by the present invention has a single crystal form of nepheline (NaAlSiO4). Calculated by molar percentage, the glass raw materials of the strengthened nepheline microcrystalline glass satisfy 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47, that is, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) can be any value in 2.32 to 4.47 such as 2.32, 2.35, 2.38, 2.40, 2.50, 2.52, 2.55, 2.60, 2.70, 2.80, 2.90, 3.0, 3.2, 3.5, 3.8, 4.0, 4.10, 4.15, 4.20, 4.25, 4.30, 4.35, 4.40, 4.42, 4.45, 4.47. This can not only make the nepheline microcrystalline glass easily obtain a visible light transmittance greater than 90%, but also improve the chemical strengthening effect of the nepheline microcrystalline glass in step S30, making the nepheline microcrystalline glass relatively easy to carry out efficient ion exchange strengthening, and the depth of the ion exchange layer is relatively large. After chemical strengthening, the strengthened nepheline microcrystalline glass obtained has good mechanical properties and can be applied to the fields of display screen devices and electronic devices, meeting the performance requirements of mobile phones for cover glass. For example, when the thickness of the strengthened nepheline microcrystalline glass is 0.6 mm, the stress intensity CS-30 of the strengthened nepheline microcrystalline glass is 174 MPa to 213 MPa; and / or, the stress depth DOL-Na of the strengthened nepheline microcrystalline glass is 134 μm to 148 μm; and / or, under the test conditions of 80-mesh sandpaper, the whole machine drop height of the strengthened nepheline microcrystalline glass is 0.9 to 1.25 m; and / or, the scratch-resistant critical load of the strengthened nepheline microcrystalline glass is 4 N to 5 N.

[0086] In some embodiments, in the step of obtaining the base glass in step S10, the heating and melting temperature is 1480 °C to 1520 °C, and the heat preservation temperature is 4 h to 10 h. The heating and melting temperature of the glass of the present invention is relatively low, which can effectively reduce energy consumption.

[0087] In some embodiments, in the step of obtaining the base glass in step S10, the annealing temperature for annealing is 490°C to 530°C; and / or, the annealing time for annealing is 2 h to 6 h.

[0088] In some embodiments of step S10, the glass raw materials of the nepheline glass-ceramics are heated to 1480°C to 1520°C and held for 4 h to 10 h to prepare a molten liquid. After homogenization and forming of the molten liquid, it is annealed at a temperature of 490°C to 530°C for 2 h to 6 h to obtain the base glass.

[0089] The crystals in the glass-ceramics are generated by controlled crystallization or induced crystallization of the base glass, and the two heat treatment stages of nucleation and crystal growth are the key to realizing the controlled crystallization of the glass-ceramics. By controlling the heat treatment of the nucleation process and the crystal growth process, the base glass can precipitate crystals with a certain quantity and size, and even change the crystallization route or the type of precipitated crystals, thereby endowing the glass-ceramics with various required properties. In some embodiments, in the step of obtaining the nepheline glass-ceramics in step S20, the temperature of the heat treatment is 550°C to 670°C, and the time of the heat treatment is 275 min to 520 min, which can prompt the glass to precipitate only the single crystal form of nepheline, and at the same time control the average crystal size range of the nepheline glass-ceramics to be 40 nm to 55 nm, so as to improve the visible light transmittance of the nepheline glass-ceramics and make the nepheline glass-ceramics meet the optical requirements of display screen devices and electronic devices.

[0090] In some embodiments of step S20, the heat treatment includes nucleation heat treatment and crystallization heat treatment, which control the nucleation and crystal growth of the base glass, so that the base glass precipitates the single crystal form of nepheline, and at the same time control the average crystal size range of the nepheline glass-ceramics to be 40 nm to 55 nm, so as to improve the visible light transmittance of the nepheline glass-ceramics and make the nepheline glass-ceramics meet the optical requirements of display screen devices and electronic devices.

[0091] In some embodiments, in the step of nucleation heat treatment, it is held at a temperature of 550°C to 570°C for 240 min to 360 min, which can prompt the glass to precipitate only the single crystal form of nepheline, and at the same time control the average crystal size range of the nepheline glass-ceramics to be 40 nm to 55 nm, so as to improve the visible light transmittance of the nepheline glass-ceramics and make the nepheline glass-ceramics meet the optical requirements of display screen devices and electronic devices.

[0092] In some embodiments, in the step of crystallization heat treatment, by holding at a temperature of 640 °C to 670 °C for 35 min to 160 min, it can promote the glass to precipitate only one single crystal form of nepheline, and at the same time control the average crystal size range of the nepheline glass-ceramics to be 40 nm to 55 nm, thereby improving the visible light transmittance of the nepheline glass-ceramics and making the nepheline glass-ceramics meet the optical requirements of display devices and electronic devices.

[0093] In some embodiments of step S30, the chemical strengthening includes a first molten salt and a second molten salt. The nepheline glass-ceramics are placed in the first molten salt for the first chemical strengthening treatment to obtain the first strengthened glass-ceramics, and then the first strengthened glass-ceramics are placed in the second molten salt for the second chemical strengthening treatment to obtain the nepheline glass-ceramics. In this embodiment, the two-step chemical strengthening treatment is performed on the nepheline glass-ceramics, which can enhance the chemical strengthening effect, make it easier for the nepheline glass-ceramics to perform efficient ion exchange strengthening, and the depth of the ion exchange layer is larger, so that the strengthened nepheline glass-ceramics obtained after chemical strengthening of the nepheline glass-ceramics have better mechanical properties. For example, when the thickness of the strengthened nepheline glass-ceramics is 0.6 mm, the stress intensity CS-30 of the strengthened nepheline glass-ceramics is 174 MPa to 213 MPa; and / or, the stress depth DOL-Na of the strengthened nepheline glass-ceramics is 134 μm to 148 μm; and / or, under the test conditions of 80-mesh sandpaper, the whole machine drop height of the strengthened nepheline glass-ceramics is 0.9 to 1.25 m; and / or, the scratch resistance critical load of the strengthened nepheline glass-ceramics is 4 N to 5 N, thereby meeting the performance requirements of display devices and electronic devices for cover glass.

[0094] In some embodiments, the first molten salt includes sodium salts, which can promote ion exchange strengthening.

[0095] In some embodiments, the sodium salts include sodium nitrate, which can promote ion exchange strengthening.

[0096] In some embodiments, the second molten salt includes potassium salts, which can promote ion exchange strengthening.

[0097] In some embodiments, the potassium salts include potassium nitrate, which can promote ion exchange strengthening.

[0098] In some embodiments, the first molten salt includes sodium nitrate with a mass concentration of 100%, which can promote ion exchange strengthening and obtain a larger ion exchange layer depth.

[0099] In some embodiments, the second molten salt includes potassium nitrate with a mass concentration of 100%, which can promote ion exchange strengthening and obtain a larger ion exchange layer depth.

[0100] In some embodiments, when the first molten salt chemically strengthens nepheline microcrystalline glass, it is in a molten state. When the heat-treated and crystallized microcrystalline glass is placed in the first molten salt for the first chemical strengthening treatment, the temperature of the first chemical strengthening treatment is 450°C to 460°C, and the heat preservation time is 150 min to 210 min.

[0101] In some embodiments, when the second molten salt chemically strengthens the first strengthened microcrystalline glass, it is in a molten state. When the first strengthened microcrystalline glass is placed in the second molten salt for the second chemical strengthening treatment, the temperature of the second chemical strengthening treatment is 440°C to 430°C, and the heat preservation time is 90 min to 120 min.

[0102] By controlling the composition of nepheline microcrystalline glass and cooperating with the chemical strengthening process, the nepheline microcrystalline glass prepared by the present invention has a relatively high light transmittance and good mechanical properties, and can be applied to the fields of display screen devices and electronic devices to manufacture the cover glass of mobile phones.

[0103] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not used to limit the present invention.

[0104] Example 1

[0105] The preparation method of the nepheline microcrystalline glass in Example 1 is as follows:

[0106] S10. Weigh the glass raw materials according to the composition of the microcrystalline glass in Table 1 and Table 2. After mixing the glass raw materials evenly, pour them into a platinum-rhodium crucible, heat to 1520°C, and keep warm for 10 h to prepare a molten liquid. After homogenizing and shaping the molten liquid, anneal it at a temperature of 530°C for 6 h, and then cool it with the furnace to obtain glass. Cut, grind, and polish the glass to obtain a base glass with a thickness of 0.6 mm.

[0107] S20. The base glass is kept warm at a temperature of 550°C for 360 min for nucleation treatment, and then kept warm at a temperature of 640°C for 160 min for crystallization treatment to obtain nepheline microcrystalline glass.

[0108] S30. Place the nepheline microcrystalline glass in a molten sodium nitrate first molten salt with a mass concentration of 100%, and keep warm at a temperature of 450°C for 210 min for strengthening treatment to obtain a first strengthened microcrystalline glass. Then place the first strengthened microcrystalline glass in a potassium nitrate second molten salt with a mass concentration of 100%, and keep warm at a temperature of 430°C for 120 min for strengthening treatment to obtain a strengthened nepheline microcrystalline glass.

[0109] Among them, the specific preparation conditions are shown in Table 1.

[0110] Examples 2 to 18

[0111] Examples 2 to 18 The nepheline microcrystalline glass was prepared with reference to the preparation method of Example 1, except for the composition of the microcrystalline glass and the specific preparation conditions. See Tables 1 and 2 for details.

[0112] Comparative Examples 1 to 7

[0113] Comparative Examples 1 and 7 The microcrystalline glass was prepared with reference to the preparation method of Example 1, except for the composition of the microcrystalline glass and the specific preparation conditions. See Table 3 for details.

[0114] Performance Testing

[0115] 1. DSC Test of Glass: The DSC test of the glass was carried out using a DSC404F3 differential scanning calorimeter produced by Netzsch, Germany. Each time, the same mass of glass powder was weighed for the test. The test temperature range was from room temperature to 1400 °C, and the heating rate was 10 °C / min. The reference material was α-Al2O3 powder.

[0116] The DSC test obtained Figures 1 to 3 , Figure 1 is the DSC diagram of the microcrystalline glass of Example 18, Figure 2 is the DSC diagram of the microcrystalline glass of Comparative Example 2, Figure 3 is the DSC diagram of the microcrystalline glass of Comparative Example 3.

[0117] 2. High-Temperature Viscosity Test of Glass: The high-temperature viscosity of the glass was tested using an RSV 1600 rotary high-temperature viscometer produced by Orton, USA according to ASTM C-965.

[0118] The high-temperature viscosity test obtained Figures 4 to 5 , Figure 4 is the high-temperature viscosity curve diagram of the microcrystalline glass of Example 4, Figure 5 is the high-temperature viscosity curve diagram of the microcrystalline glass of Comparative Example 2.

[0119] 3. Crystal Phase Test of Glass (i.e., XRD Test): The heat-treated glass obtained after the heat treatment in step S20 was ground into powder and passed through a 200-mesh sieve, and was measured using a D8 advance A25 X-ray diffractometer produced by Bruker, Germany. The test conditions were as follows: 2.2 kW, Cu target, tube voltage 40 Kv, tube current 40 mA, and the scanning range was 5° to 70°.

[0120] The XRD test obtained Figure 6 , Figure 6 is the XRD diagram (glass crystal phase diagram) of the microcrystalline glass of Example 11.

[0121] 4. Average crystal size test of glass (i.e., SEM test): It was measured using a Sigma300 field emission scanning electron microscope produced by Carl Zeiss in Germany. The glass-ceramics were surface-treated with HF acid, and then Pt was coated on the surface of the glass-ceramics. The diameter of the microcrystalline grains was observed under the scanning electron microscope, and the average crystal size of the glass was calculated by summing up the average diameter sizes of all crystal profiles and dividing by the number of crystals in the electron microscope image.

[0122] Obtained by SEM test Figure 7 , Figure 7 is the SEM image (glass surface morphology image) of the glass-ceramics of Example 13.

[0123] 5. Visible light transmittance test of glass: It was measured using a spectrophotometer (PE Lambda950). The measurement wavelength range was 380 nm to 780 nm, the slit width was 5 nm, the scanning speed was medium, and the sampling interval was 5 nm.

[0124] 6. Drop height test of the whole glass testing machine: A controlled drop tester produced by Shenzhen Green Map Precision Instruments Co., Ltd., model LT-SKDL-CD2000, was used. The weight of the simulated mobile phone model was 180 g, and the ground was covered with 80-mesh silicon carbide sandpaper (simulating a rough ground). It faced down at the free-fall speed, starting from 50 cm, increasing by 5 cm each time until the glass was broken (cracks appeared as broken).

[0125] 7. Scratch resistance test of glass: According to GB / T 39815-2021 "Test Method for Scratch Resistance of Ultra-thin Glass", a glass scratch resistance tester produced by Beijing Xuhui Xinrui Technology Co., Ltd., model STR-300, was used, and a Knoop indenter was used; the critical load was defined as the normal load applied when continuous plow-shaped scratches with a length greater than 1 mm began to appear on the surface of the specimen.

[0126] 8. Stress value test of glass: The FSM-6000LeUV birefringence stress meter and the scattered light photoelastic stress meter SLP-2000 were used to test CS and DOL of the strengthened glass of each example after ion exchange. Using a birefringence imaging system, polarized light of a specific wavelength passed through the glass with a stress gradient, generating a refraction optical path difference, and calculating relevant stress distribution indicators: CS-30, CS-K, DOL-Na, DOL-K.

[0127] Note: CS-30, also known as CS-Na30, refers to the compressive stress value at a depth of 30 microns of the strengthened glass sample after strengthening. Since its compressive stress value is mainly due to the exchange of Na ions in the strengthening salt for Li ions in the glass, it is called CS-Na30;

[0128] CS-K refers to the compressive stress value on the surface of toughened glass. Since it mainly replaces Na ions in the glass with K ions in the toughening salt, it is called CS-K;

[0129] DOL-Na refers to the exchange depth of Na ions and Li ions, and also represents the depth of compressive stress of toughened glass;

[0130] DOL-K refers to the exchange depth of K and Na ions.

[0131] The data obtained from the above tests are respectively recorded in Tables 1 to 3.

[0132] Table 1

[0133]

[0134]

[0135] Table 2

[0136]

[0137] Table 3

[0138]

[0139]

[0140] By comparing the comparative examples in Table 3 with the examples in Tables 1 to 2, it can be seen that:

[0141] The glass compositions and chemical strengthening treatment processes of Examples 1 to 18 are all within the requirements of the present invention. Figure 1 This is the DSC diagram of the strengthened nepheline microcrystalline glass of Example 18. The DSC test spectrum of the glass shows obvious crystallization peaks, indicating that the glass has the ability of overall crystallization.

[0142] Figure 4 This is the high-temperature viscosity curve diagram of the strengthened nepheline microcrystalline glass of Example 4. The high-temperature viscosity of the glass is relatively low, and the glass melting temperature is 1480 - 1520 °C.

[0143] Figure 6 This is the XRD diagram of the strengthened nepheline microcrystalline glass of Example 11. The average crystal size of the strengthened nepheline microcrystalline glass is 40 nm - 55 nm, and only nepheline crystals are precipitated after the glass is crystallized.

[0144] Figure 7 This is the SEM diagram of the strengthened microcrystalline glass of Example 13. The visible light transmittance of the nepheline microcrystalline glass is 90.11% - 91.19% (the thickness of the microcrystalline glass is 0.6 mm).

[0145] The strengthened nepheline microcrystalline glass obtained by two-step chemical strengthening of the nepheline microcrystalline glass of Examples 1 to 18 has a CS-30 value of 174 to 213 MPa, a stress depth DOL-Na value of 134 to 148 μm. Under the test conditions of 80-mesh sandpaper, the whole machine drop height is 0.9 to 1.25 m; the critical scratch resistance load is 4 to 5 N. The strengthened nepheline microcrystalline glass of the embodiments of the present invention has excellent optical properties, excellent drop resistance and scratch resistance, and can meet the application requirements in the fields of display devices or electronic devices, etc.

[0146] The microcrystalline glass of Comparative Example 1 does not contain Li2O and K2O, and (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) is equal to 1.16, exceeding the range of 2.32 to 4.47, and the glass composition exceeds the requirements of the present invention. Comparative Example 1 is a typical design of the base glass composition based on the stoichiometric ratio of nepheline (NaAlSiO4). The glass of Comparative Example 1 does not contain Li2O. After one-step strengthening of the nepheline microcrystalline glass, the drop resistance height of the glass under the test conditions of 80-mesh sandpaper is <0.5 m (the starting height of the drop resistance test is 0.5 m), and the critical scratch resistance load is 0.5 N, and the mechanical properties are not ideal.

[0147] The microcrystalline glass of Comparative Example 2 does not contain Li2O and K2O, and (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) = 5.88, exceeding the range of 2.32 to 4.47, and the glass composition exceeds the requirements of the present invention. Comparative Example 2 designs the base glass composition with a high silicon content based on the stoichiometric ratio of nepheline (NaAlSiO4), and the glass melting temperature is high, reaching 1620 °C. Figure 5 It is the high-temperature viscosity curve graph of the microcrystalline glass of Comparative Example 2; Figure 2 It is the DSC graph of the microcrystalline glass of Comparative Example 2; this glass does not contain Li2O. After one-step strengthening of the nepheline microcrystalline glass, the drop resistance height of the glass under the test conditions of 80-mesh sandpaper is <0.5 m (the starting height of the drop resistance test is 0.5 m), and the critical scratch resistance load is 0.5 N, and the mechanical properties are not ideal.

[0148] In Comparative Example 3, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) = 2.12, exceeding the range of 2.32 to 4.47, SiO2 = 52.5 > 49.9, Al2O3 = 12.5 < 15, Na2O = 11 < 14, Li2O = 10 > 9.6, B2O3 = 4.9 > 4.5, ZnO = 2 < 2.5, and the glass composition exceeds the requirements of the present invention. Figure 3DSC diagram of the microcrystalline glass of Comparative Example 3. The DSC test results show no obvious crystallization peak. After the nepheline microcrystalline glass is strengthened by the two-step method, the glass stress CS-30 value is relatively low, which is 102 MPa. Under the test condition of 80-mesh sandpaper, the anti-drop height is 0.5 m, and the critical scratch resistance load is 1 N. The mechanical properties are not ideal.

[0149] In Comparative Example 4, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) = 4.69, exceeding the range of 2.32 - 4.47, Al2O3 = 14 < 15, K2O = 2 > 1.6, TiO2 = 1.5 > 1.2. The high TiO2 content in the glass results in a transmittance < 90%. After the nepheline microcrystalline glass is strengthened by the two-step method, the glass stress CS-30 value is relatively low, which is 111 MPa. Under the test condition of 80-mesh sandpaper, the anti-drop height is 0.55 m, and the critical scratch resistance load is 1 N. The mechanical properties are not ideal.

[0150] In Comparative Example 5, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) = 4.84, exceeding the range of 2.32 - 4.47, SiO2 = 56.2 > 49.9, Al2O3 = 14 < 15, Na2O = 9.5 < 14, B2O3 = 1.7 < 2.5, TiO2 = 2 > 1.2. The glass composition exceeds the requirements of the present invention, and the high TiO2 content in the glass results in a transmittance < 90%. The DSC test results of the glass show no obvious crystallization peak. After the glass is strengthened by the two-step method, the glass stress CS-30 value is relatively low, which is 101 MPa. Under the test condition of 80-mesh sandpaper, the anti-drop height is 0.5 m, and the critical scratch resistance load is 1 N. The mechanical properties are not ideal.

[0151] The composition of Comparative Example 6 is the same as that of Example 9, but the heat treatment process of Comparative Example 6 is: nucleation treatment at a temperature of 570 °C for 300 min and crystallization treatment at a temperature of 680 °C for 120 min. The crystallization heat treatment process exceeds the requirements of the present invention. After the glass is heat-treated by this process, the whole glass turns blue-white and is close to devitrification, and the transmittance is only 5.1%. The glass powder is tested by XRD, and the results show nepheline, Li3PO4, Al 0.16 Zr 0.84 O 1.92 crystalline phases. Because the optical properties of the glass are too poor, no chemical strengthening treatment and subsequent performance tests are carried out.

[0152] In Comparative Example 7, (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) = 5.59 > 4.47, exceeding the range of 2.32 to 4.47, and B2O3 = 2 < 2.5, so the glass composition exceeds the requirements of the present invention. Although the glass-ceramics with a nepheline crystal phase can be prepared in Comparative Example 7, its chemical strengthening performance is weak, the glass stress CS-30 value is relatively low at 122 MPa, the anti-drop height is 0.65 m under the test condition of 80-mesh sandpaper, and the scratch-resistant critical load is 1 N, so the mechanical properties are not ideal.

[0153] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A strengthened nepheline microcrystalline glass, characterized in that, The average crystal size range of the strengthened nepheline microcrystalline glass is 40 nm to 55 nm; The composition of the strengthened nepheline microcrystalline glass includes SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, ZnO, ZrO2 and P2O5, and calculated by molar percentage, it satisfies 2.32 ≤ (1.5Na2O + 2.3K2O + 1.6Li2O) / (3.4B2O3) ≤ 4.47; The stress intensity CS-30 of the strengthened nepheline microcrystalline glass ≥ 174 MPa, and the CS-30 refers to the compressive stress value of the strengthened nepheline microcrystalline glass at a depth of 30 microns.

2. The enhanced nepheline microcrystalline glass according to claim 1, wherein, The visible light transmittance of the strengthened nepheline microcrystalline glass > 90%; 3. The strengthened nepheline microcrystalline glass according to claim 1, characterized in that, When the thickness of the strengthened nepheline microcrystalline glass is 0.6 mm: The stress depth DOL-Na of the strengthened nepheline microcrystalline glass is 134 μm to 148 μm; and / or, under the test conditions of 80-mesh sandpaper, the whole machine drop height of the strengthened nepheline microcrystalline glass is 0.9 m to 1.25 m; and / or, the scratch resistance critical load of the strengthened nepheline microcrystalline glass is 4 N to 5 N.

4. The preparation method of the strengthened nepheline microcrystalline glass according to any one of claims 1 to 3, characterized in that, It includes the following steps: Weigh the glass raw materials according to the composition of the strengthened nepheline microcrystalline glass, and the glass raw materials are heated, melted, homogenized, formed and annealed to obtain the base glass; The base glass is heat-treated to obtain nepheline microcrystalline glass; The nepheline microcrystalline glass is chemically strengthened to obtain the strengthened nepheline microcrystalline glass.

5. The method for preparing the strengthened sodium nepheline glass-ceramics according to claim 4, characterized in that: The glass raw materials include the following components: SiO2: 45.1% to 49.9%, Al2O3: 15% to 17.5%, Na2O: 14% to 16.5%, K2O: 0.5% to 1.6%, Li2O: 7% to 9.6%, B2O3: 2.5% to 4.5%, ZnO: 2.5% to 4.9%, TiO2: 0 to 1.2%, ZrO2: 1.4% to 2.8%, P2O5: 1.8% to 4%.

6. The preparation method of the strengthened nepheline microcrystalline glass according to claim 4, characterized in that, The chemical strengthening includes a first molten salt and a second molten salt. The nepheline microcrystalline glass is subjected to a first chemical strengthening treatment in the first molten salt to obtain a first strengthened microcrystalline glass, and the first strengthened microcrystalline glass is subjected to a second chemical strengthening treatment in the second molten salt to obtain the strengthened nepheline microcrystalline glass.

7. The preparation method of the strengthened nepheline microcrystalline glass according to claim 6, wherein The first molten salt includes a sodium salt with a mass concentration of 100%; and / or, the second molten salt includes a potassium salt with a mass concentration of 100%.

8. The method for preparing the strengthened sodium nepheline glass-ceramics according to claim 6, characterized in that: The first molten salt includes a sodium salt, and the sodium salt includes sodium nitrate; and / or, the second molten salt includes a potassium salt, and the potassium salt includes potassium nitrate.

9. The preparation method of the strengthened nepheline microcrystalline glass according to claim 4, characterized in that, The temperature of the first chemical strengthening treatment is 450 °C to 460 °C, and the heat preservation time is 150 min to 210 min; and / or, the temperature of the second chemical strengthening treatment is 440 °C to 430 °C, and the heat preservation time is 90 min to 120 min.

10. An application of the strengthened nepheline microcrystalline glass according to any one of claims 1 to 3 or the strengthened nepheline microcrystalline glass obtained by the preparation method of claim 4.

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