Nepheline glass ceramic with moth-eye-like structure and preparation method of nepheline glass ceramic

Abstract

The invention relates to the technical field of nepheline glass ceramics, and discloses nepheline glass ceramics with a moth-eye-like structure and a preparation method of the nepheline glass ceramics. The nepheline glass ceramic with the moth-eye-like structure comprises a nepheline glass ceramic substrate layer and a moth-eye-like structure layer, wherein the nepheline glass ceramic substrate layer and the moth-eye-like structure layer are of an integrated structure; the nepheline glass ceramic with the moth-eye-like structure has the highest transmittance TrM of more than or equal to 98% and the lowest reflectivity ReM of less than or equal to 2.0% under visible light with the wavelength of 550nm; the moth-eye-like structure is a cone arranged in an array mode, the bottom diameter of the cone ranges from 10 nm to 70 nm, the height of the cone ranges from 10 nm to 70 nm, and the distance between every two adjacent cones ranges from 10 nm to 70 nm.

Description

Technical Field

[0001] The present invention relates to the technical field of nepheline glass-ceramics, and particularly to a nepheline glass-ceramic with a moth-eye-like structure and a preparation method thereof. Background Art

[0002] Due to its excellent mechanical strength, thermal stability and chemical inertness, nepheline glass-ceramics are widely used in optical devices such as display covers and touch modules. However, its high refractive index characteristic results in significant Fresnel reflection loss on the surface, reducing the optical transmittance.

[0003] In recent years, the bionic moth-eye structure can reduce the broadband reflectance to less than 0.5% through the gradient refractive index effect, providing a new idea for breaking through the above limitations. However, there are certain challenges in constructing high-precision nanostructures on glass-ceramics, that is, the high-temperature crystallization process will affect the nano-morphology. For example, in the common lithium disilicate system glass-ceramics, the crystal morphology is rod-shaped and often forms an interlocking structure during crystal growth. It is difficult to directly obtain a moth-eye structure with small size and orderly arrangement through etching. While the glass-ceramics of the nepheline system have a spherical crystal morphology and are more likely to obtain a suitable moth-eye structure through etching, but no specific research has been carried out yet.

[0004] Therefore, the existing technology still needs to be further improved and developed. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present invention is to provide a nepheline glass-ceramic with a moth-eye-like structure and a preparation method thereof. The aim is to solve the problem of low optical transmittance of existing nepheline glass-ceramics.

[0006] The above object of the present invention is achieved by the following technical solution: A nepheline glass-ceramic with a moth-eye-like structure, which includes: a nepheline glass-ceramic base layer and a moth-eye-like structure layer, and the nepheline glass-ceramic layer and the moth-eye structure layer are an integral structure;

[0007] The average transmittance TrA of the nepheline glass-ceramic with a moth-eye-like structure at a visible light wavelength of 550 nm is ≥96%, the highest transmittance TrM ≥98%, the average reflectance ReA ≤2.5%, and the lowest reflectance ReM ≤2.0%;

[0008] The moth-eye-like structure is an array of cones, and the bottom diameter of the cone is 10 nm to 70 nm, the height is 10 nm to 70 nm, and the distance between adjacent cones is 10 nm to 70 nm.

[0009] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0010] As a preferred technical solution, the nepheline glass-ceramics with a moth-eye-like structure, wherein, in terms of the molar ratio of oxides, the nepheline glass-ceramics comprise:

[0011] SiO2: 42.00 - 52.00%,

[0012] Al2O3: 16.00 - 21.00%,

[0013] Na2O: 12.00 - 21.00%,

[0014] ZrO2: 1.00 - 3.50%,

[0015] TiO2: 0.00 - 2.00%,

[0016] P2O5: 1.00 - 5.00%,

[0017] CaO: 0.00 - 2.00%,

[0018] Li2O: 8.00 - 16.00%,

[0019] K2O: 0.00 - 2.00%,

[0020] SnO2: 0.0 - 0.2%,

[0021] and B₂O₃: 0 - 3.00%;

[0022] The composition of the nepheline glass-ceramics further contains 0.1 - 0.80% of a clarifying agent, and the clarifying agent is selected from one or more of NaCl, Sb₂O₃, As₂O₃, nitrates, and sulfates;

[0023] The sum of the percentages of the components of the nepheline glass-ceramics containing the clarifying agent is 100%.

[0024] As a preferred technical solution, the nepheline glass-ceramics with a moth-eye-like structure, wherein the main crystal forms of the nepheline glass-ceramics are one or more of natrolite, eucryptite, and triclinic nepheline, and the secondary crystal forms are one or more of β-quartz solid solution and sodium silicate. The crystallinity of the nepheline glass-ceramics is 30 - 60%, and the average grain size is 20 - 40 nm.

[0025] As a preferred technical solution, the nepheline glass-ceramics with a moth-eye-like structure, wherein the moth-eye-like structure layer is obtained by etching the surface of the nepheline glass-ceramics base layer with an etching solution.

[0026] As a preferred technical solution, the nepheline microcrystalline glass with a moth-eye-like structure, wherein the nepheline microcrystalline glass is the nepheline microcrystalline glass after ion-exchange chemical strengthening treatment.

[0027] As a preferred technical solution, the nepheline microcrystalline glass with a moth-eye-like structure, wherein the temperature used for ion-exchange chemical strengthening treatment is 380-560 °C; the molten salt used contains one or two of sodium ions, lithium ions and potassium ions.

[0028] In a second aspect, a preparation method of the nepheline microcrystalline glass with a moth-eye-like structure as described above, which includes:

[0029] Mix the compounds constituting the nepheline microcrystalline glass evenly, pour them into a platinum crucible, melt at a temperature of 1500-1650 °C, and clarify and homogenize at a temperature of 1300-1400 °C to obtain a molten liquid;

[0030] Form the molten liquid by any one of the forming methods such as roll pressing method, continuous melting and casting method, floating method, and overflow method, and anneal after forming to obtain a base glass;

[0031] Heat the base glass at a heating rate of 1-10 °C / min to a nucleation temperature of 520-560 °C and hold for 3-5 hours, and then heat at a heating rate of 1-10 °C / min to a crystallization temperature of 620-690 °C and hold for 10-120 min to obtain a microcrystalline glass;

[0032] Machine-process the microcrystalline glass to obtain a polished microcrystalline glass sheet;

[0033] Immerse the polished microcrystalline glass sheet in an etching solution at 20-30 °C for etching to obtain the nepheline microcrystalline glass with a moth-eye-like structure.

[0034] As a preferred technical solution, the preparation method of the nepheline microcrystalline glass with a moth-eye-like structure, wherein the etching solution, calculated by mass percentage, includes: 3-5% hydrofluoric acid, 2-5% silicon dioxide, 1-2% barium sulfate, 1-3% sodium carboxymethylcellulose, and 85-91% pure water.

[0035] In a third aspect, a nepheline microcrystalline glass with a moth-eye-like structure as described above or a nepheline microcrystalline glass with a moth-eye-like structure prepared by the preparation method as described above is used as a material for preparing a cover plate of a display device.

[0036] Beneficial effects: The nepheline microcrystalline glass with a moth-eye-like structure provided by the present invention has a high transmittance (the highest transmittance TrM≥98%) by setting a moth-eye-like structure layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the glass-ceramics with moth-eye-like structure according to the present invention.

[0038] Figure 2 XRD pattern of the glass-ceramics substrate with nepheline and microcline as the main crystal phases in Example 1.

[0039] Figure 3 SEM micrograph of the crystals in the glass-ceramics before etching in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the 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. The description of at least one exemplary embodiment below is actually only illustrative and in no way restrictive of the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0042] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components and / or their combinations.

[0043] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: Similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0044] The relevant special names and related measurement methods involved in the present invention are explained as follows.

[0045] Glass-ceramics: Also known as glass ceramics, it is a type of solid composite material that contains both a glass phase and a crystalline phase and is prepared by targeted and controlled crystallization of a base glass. Note: The crystalline phase here may also be referred to as the crystal phase, microcrystalline phase, or crystalline phase in other patent documents.

[0046] In the present invention, the glass-ceramic substrate refers to the glass-ceramics that have not undergone surface etching treatment.

[0047] Crystallinity: The percentage of the total mass of crystals / crystalline phases / grains in the total mass of the glass-ceramics. It should be understood that the crystalline phase and grains both refer to the crystals precipitated in the glass-ceramics.

[0048] Transmittance: The ratio of the radiant energy that is projected and transmitted through an object to the total radiant energy projected onto the object during the process where the incident light flux enters from the illuminated surface or the incident surface of the medium and exits from the other side.

[0049] Moth-eye-like structure: Also known as a biomimetic moth-eye structure, it refers to a structure similar to the compound eyes of moths.

[0050] The moth-eye-like structure in the present invention is an irregularly arranged and nanostructured convex structure with specific characteristics formed on the surface of the glass-ceramic substrate by etching the surface of the glass-ceramic substrate with an etching solution, and it is olive-like in shape.

[0051] The etching reaction mechanism of the present invention is that the glass phase in the glass-ceramic substrate reacts with HF, and this reaction includes the reaction of HF with SiO2 and the reaction of HF with metal oxides in the glass phase. For example, the following reactions occur:

[0052] SiO2 + 4HF = SiF4↑ + 2H2O;

[0053] Al2O3 + 6HF = 2AlF3 + 3H2O;

[0054] Na2O + 2HF = 2NaF + H2O;

[0055] The reaction product SiF4 is generally gaseous under normal conditions. Part of it will volatilize, and the other part will dissolve in the solution and continue to react. For example, the following reactions occur:

[0056] 4SiF4 + 2HF + 3H2O = 3H2SiF6 + H2SiO3;

[0057] 3SiF4 + 2AlF3 = Al2(SiF6)3;

[0058] SiF4 + 2NaF = Na2SiF6.

[0059] Finally, the glass phase on the surface of the glass-ceramic substrate of the present invention is corroded and consumed, leaving acid-resistant crystal substances, and a nano-scale raised structure with a specific distribution and a specific morphology is formed on the surface of the glass-ceramic substrate, that is, a moth-eye-like structure layer with a specific structure is formed.

[0060] As Figure 1 shown, a nepheline glass-ceramic with a moth-eye-like structure provided by the present invention includes: a nepheline glass-ceramic base layer 10 and a moth-eye-like structure layer 20, and the nepheline glass-ceramic layer and the moth-eye structure layer are an integral structure; the average transmittance TrA of the nepheline glass-ceramic with a moth-eye-like structure at a visible light wavelength of 550 nm is ≥96%, the highest transmittance TrM ≥98%, the average reflectance ReA ≤2.5%, and the lowest reflectance ReM ≤2.0%; the moth-eye-like structure is a cone arranged in an array, and the bottom diameter d of the cone is 10 nm to 70 nm, the height h is 10 nm to 70 nm, and the spacing s between adjacent cones is 10 nm to 70 nm (note: the adjacent spacing is the spacing between adjacent center points).

[0061] In one implementation manner of the present invention, the etching solution includes the following components in terms of mass percentage: the used etching HF: 5 wt%, SiO2: 2 - 5 wt%, BaSO4: 1 - 2 wt%, sodium carboxymethylcellulose: 1 - 3 wt%

[0062] Pure water: 85 - 91 wt%. The concentration of hydrofluoric acid is greater than or equal to 40.00 wt%. The particle size of barium sulfate is less than 2 mm, and the purity is greater than 98%.

[0063] In the present invention, the main crystal phase of the glass-ceramic substrate includes one or more of nepheline, eucryptite, and triclinic nepheline, the secondary crystal form is a β-quartz solid solution, and one or more of sodium silicate. The glass-ceramic substrate with a specific main crystal phase and different degrees of crystallinity can bring different improvement effects to the transmittance of the glass-ceramic with a moth-eye-like structure obtained after etching in the visible light range; among them, a lower degree of crystallinity often results in less improvement in the transmittance of the glass-ceramic with a moth-eye-like structure because a lower degree of crystallinity indicates a low content of the main crystal phase in the glass-ceramic substrate, and the distribution of the nano-scale protrusion structures formed after etching the glass-ceramic substrate is not uniform enough and the number is small, thereby resulting in less improvement in the transmittance of the glass-ceramic with a moth-eye-like structure in the visible light range.

[0064] In one implementation of the present invention, the degree of crystallinity of the glass-ceramic substrate of the present invention is 30-60%, such as 35-55%. The average grain size of the glass-ceramic substrate of the present invention is 20-40 nm, such as 25-40 nm.

[0065] In one implementation of the present invention, the height range of the cone is 10 nm to 70 nm. In some embodiments, the bottom diameter of the cone is 10 nm to 70 nm. In some embodiments, the spacing between adjacent cones is 10-70 nm.

[0066] In one implementation of the present invention, measured on the surface of the moth-eye-like structure layer on the main surface, the average transmittance TrA of the moth-eye-like structure at a wavelength of 550.0 nm light is ≥96%, the highest transmittance TrM ≥98%, the average reflectance ReA ≤2.5, and the lowest reflectance ReM ≤2.0%.

[0067] In one implementation of the present invention, the glass-ceramic with a moth-eye-like structure provided by the present invention, calculated by the molar ratio of oxides, includes: SiO2: 42.00% - 52.00%; Al2O3: 16.00% - 21.00%; Na2O: 12.00 - 21.00%; ZrO2: 1% - 3.50%; TiO2: 0% - 2.00%; P2O5: 1% - 5.00%; CaO: 0% - 2.00%; Li2O: 8.00% - 16.00%; K2O: 0% - 2.00%; SnO2: 0% - 0.20%; B2O3: 0% - 3.00%.

[0068] The glass-ceramic composition provided by the present invention further contains 0.1-0.80% of a clarifying agent, and the clarifying agent is selected from one or more of NaCl, Sb2O3, As2O3, nitrates, and sulfates.

[0069] Specifically, as one of the main components of the network-forming oxides of the base glass and the glass-ceramics, SiO2 is an important component that forms the Si-O tetrahedra in the main body and constructs the network structure. Based on the raw materials (compounds) involved in the embodiments of the present application, the molar fraction of SiO2 is 42-52%, for example, the molar fraction of SiO2 is 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, and any one of the ranges formed by any two of the above values. Preferably, it is 44-50%.

[0070] Al2O3 is an intermediate oxide for glass formation and is also a main component of crystal forms such as nepheline and triclinic nepheline. It can significantly improve the thermal stability of the base glass and the glass-ceramics. At the same time, since [AlO4] is larger in volume than [SiO4], it can provide a larger space for ion exchange. Therefore, Al2O3 can promote the progress of ion exchange. Excessive Al2O3 will increase the viscosity of the glass and is not conducive to melting. Based on the raw materials involved in the embodiments of the present application, the molar fraction of Al2O3 is 16-21%, for example, the molar fraction of Al2O3 is 16%, 17%, 18%, 19%, 20%, 21%, and any one of the ranges formed by any two of the above values. Preferably, it is 16-20%.

[0071] Na2O is one of the main components of crystal forms such as nepheline, triclinic nepheline, and sodium silicate, and is also an important element in the subsequent chemical strengthening process. At the same time, Na2O is a flux for the high-temperature melting of the base glass and can significantly reduce the melting temperature of the base glass. However, when the content of Na2O is higher than 21%, the chemical stability of the glass-ceramics is significantly reduced. Therefore, the ideal molar fraction of Na2O is less than or equal to 21%. At this time, both the melting temperature can be maintained within a suitable range and good ion exchange characteristics can be ensured. Based on the raw materials involved in the embodiments of the present application, the molar fraction of Na2O is 12-21%, for example, the molar fraction of Na2O is 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, and any one of the ranges formed by any two of the above values. Preferably, it is 14-20%.

[0072] Li2O is an oxide with relatively high alkali metal activity and is an external glass network oxide. As one of the additives to reduce the high-temperature viscosity of the base glass, it can significantly improve the high-temperature fluidity of the base glass. At the same time, Li +In the glass-ceramics provided by the present application, it can participate in the ion-exchange chemical strengthening reaction to further enhance the mechanical properties of the glass-ceramics. For the raw materials involved in the embodiments of the present application, the molar fraction of Li2O is 8-16%, for example, the molar fraction of Li2O is 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, and any one within the range formed by any two of the above values. Preferably, it is 8-15%.

[0073] ZrO2 is an intermediate oxide for glass formation, which can improve the chemical stability of the glass, increase the hardness of the glass, as well as the scratch resistance and drop resistance of the glass. At the same time, due to its high cation charge and strong field strength, ZrO2 has a large accumulation effect on the glass structure and is commonly used as a nucleating agent in glass-ceramics. However, excessive ZrO2 will significantly increase the viscosity of the glass and affect the forming ability of the glass. For the raw materials involved in the embodiments of the present application, the molar fraction of ZrO2 is 1-3.5%, for example, the molar fraction of ZrO2 is 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and any one within the range formed by any two of the above values. Preferably, it is 1-3%.

[0074] P2O5 can be used as a nucleating agent in the base glass and glass-ceramics, which can promote the phase separation and overall crystallization ability of the base glass. If the concentration of P2O5 is too low, the base glass will not crystallize, and only crystals will form from the surface inward at a higher temperature and lower viscosity; if the concentration of P2O5 is too high, it will be difficult to control devitrification during the cooling process of forming the base glass. For the raw materials involved in the embodiments of the present application, the molar fraction of P2O5 is 1-5%, for example, the molar fraction of P2O5 is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, and any one within the range formed by any two of the above values. Preferably, it is 1.5%-4.5%.

[0075] TiO2 is one of the nucleating agents for crystal nucleation and growth in glass-ceramics, which can effectively promote the crystal nucleation growth of the base glass during the nucleation and crystallization treatment, and at the same time improve the stability of the glass; the introduction of TiO2 effectively promotes the precipitation of crystal nuclei during the nucleation process. At the same time, the introduction of TiO2 easily causes phase separation of the base glass, resulting in crystallization and affecting the formation of the glass. For the raw materials involved in the present application, the molar fraction of TiO2 is 0-2%, for example, the molar fraction of TiO2 is 0, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, and any one within the range formed by any two of the above values. Preferably, it is 0-2%.

[0076] K2O is often added to reduce the high-temperature viscosity of the base glass, significantly improve the formability and fluidity of the base glass at high temperatures, and at the same time significantly reduce the crack incidence rate. A small amount of added K2O can slow down the crystallization behavior that occurs during the forming of the base glass. For the materials involved in the embodiments of the present invention, the molar proportion content range of K2O is 0.0 - 2.0%, preferably 0.0 - 1.50%, and specifically in the present invention, it can be 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% and any value within the range composed of any two of the above values.

[0077] SnO2 is an effective clarifying agent for the base glass. Its introduction is beneficial to reducing the formation of gas defects in the glass melt, reducing the number of melt bubbles, and improving the clarification effect. In the embodiments of the present invention, the content range of SnO2 is 0.0 - 0.2%, and specifically it can be 0.0%, 0.1%, 0.2% and any value within the range composed of any two of the above values.

[0078] As an external oxide of the glass network, B2O3 can effectively ensure the chemical stability of the base glass and the glass-ceramics. Among them, a certain amount of B2O3 can control the linear thermal expansion coefficient of the base glass and the glass-ceramics, and at the same time maintain the chemical durability and mechanical strength of the ceramicized bulk glass-ceramics. For the moth-eye structure glass-ceramics involved in the embodiments of the present invention, the molar proportion content range of B2O3 is 0 - 3.0%, preferably 0 - 2.5%, and specifically in the present invention, it can be 0.0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0% and any value within the range composed of any two of the above values. Too high or too low content of B2O3 makes the chemical resistance of the glass-ceramics material formed after the nucleation and crystallization of the base glass unstable.

[0079] As a common glass additive, CaO has multiple functions. It can lower the melting point of the glass, improve the hardness and strength of the glass, improve the transparency and corrosion resistance of the glass, and at the same time increase the thermal stability of the glass. For the moth-eye structure glass-ceramics involved in the embodiments of the present invention, the molar proportion content range of CaO is 0% - 2.0%, and specifically in the present invention, it can be 0.0%, 0.5%, 1.0%, 1.5%, 2.0% and any value within the range composed of any two of the above values.

[0080] The clarifying agent is selected from one or more of NaCl, Sb2O3, As2O3, nitrates, and sulfates, which can effectively homogenize the components of the precursor glass and reduce the formation of adverse substances such as bubbles and stones. For the raw materials involved in the embodiments of the present application, the total molar content of the clarifying agent is 0.1-0.8%, and in the embodiments, the molar fractions of one or more of the three are 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% and any one within the range formed by any two of the above values.

[0081] The preparation method of the microcrystalline glass with a moth-eye-like structure provided by the present invention includes mixing the compounds corresponding to the oxides of the components of the microcrystalline glass evenly in proportion, pouring them into a platinum crucible, melting at 1500-1650°C for not less than 3 hours, clarifying and homogenizing at 1300-1400°C for not less than 60 minutes, and forming by one of the forming methods such as roll pressing method, continuous melting and casting method, floating method, and overflow method, and annealing to obtain the base glass.

[0082] The preparation method of the microcrystalline glass with a moth-eye-like structure provided by the present invention, wherein the heat treatment includes nucleation treatment and crystallization treatment. The obtained base glass is heated at a heating rate of 1-10°C / min to the nucleation temperature of 520-560°C and held for 4 hours, and then heated at a heating rate of 1-10°C / min to the crystallization temperature of 620-690°C and held for 10-120 minutes to obtain the microcrystalline glass.

[0083] The preparation method of the microcrystalline glass with a moth-eye-like structure provided by the present invention includes machining the microcrystalline glass, including processes such as cutting, grinding, and polishing to obtain a ground and polished microcrystalline glass sheet with uniform surface and thickness.

[0084] The surface etching treatment provided by the present invention is: placing the microcrystalline glass substrate of the obtained ground and polished sheet in an etching solution for ultrasonic etching reaction. After the reaction, the microcrystalline glass substrate is taken out and successively subjected to cleaning treatment and drying treatment to obtain the microcrystalline glass with a moth-eye-like structure; preferably, the temperature of the etching solution is 20-30°C; preferably, the time of the ultrasonic etching reaction is 10-60 minutes.

[0085] The microcrystalline glass with a moth-eye-like structure provided by the present invention can be chemically strengthened by ion exchange to obtain a strengthened moth-eye structure microcrystalline glass; the chemically strengthened microcrystalline glass includes a compressive stress layer region extending from the surface of the microcrystalline glass to the compressive depth, and has a tensile stress inside the chemically strengthened microcrystalline glass. By forming a compressive stress layer on the surface of the microcrystalline glass, it is beneficial to further improve the mechanical properties of the microcrystalline glass.

[0086] The microcrystalline glass with a strengthened moth-eye structure provided by the present invention, the salt bath for chemical strengthening treatment is a mixed molten salt, and the composition of the mixed molten salt includes: 0 < NaNO3 < 100 wt%, 0 < KNO3 < 100 wt%, 0 < LiNO3 ≤ 0.2 wt%.

[0087] For the microcrystalline glass with a strengthened moth-eye structure provided by the present invention, the temperature of the salt bath for chemical strengthening treatment is 380°C to 560°C, and the time of the chemical strengthening treatment is 0.5 h to 24.0 h. Using the above strengthening process for chemical strengthening is beneficial to improving the chemical strengthening efficiency and ensuring that the chemically strengthened microcrystalline glass obtains the desired stress level.

[0088] Physical and chemical property test methods

[0089] (1) XRD test and Jade analysis

[0090] Through the Rigaku Smartlab X-ray diffraction (XRD) test, the crystal phase composition of the microcrystalline glass can be analyzed; using JADE, the crystal phase composition, degree of crystallization, and the proportion of each crystal phase can be analyzed, and the results are as Figure 2 shown.

[0091] The present invention is illustrated as follows through specific embodiments:

[0092] In the microcrystalline glass substrates used in Examples 1-5 in Table 1 of the present invention, calculated according to the molar percentage of oxides, it includes the following components. It should be understood that, calculated according to the molar percentage of oxides, the composition of the base glass used to prepare the microcrystalline glass substrate should be the same as that of the microcrystalline glass substrate. Only the following embodiments use the microcrystalline glass substrate with this composition, but the composition of the microcrystalline glass substrate that can be used in the present invention is not limited to this component. Figure 2 XRD spectrum of Example 1 with natrolite and microcline as the main crystal phases. Taking these two crystal forms as the main crystal phases, corresponding to Figure 3 the crystal morphology in, compared with crystal morphologies such as rod-shaped, needle-shaped, and sheet-shaped, this morphology is more likely to obtain conical moth-eyes after etching, and at the same time, the shape is easier to control during the etching process. In addition, through the etching method described in Table 2, the moth-eye structure microcrystalline glass in Table 3 is obtained. The moth-eye structure microcrystalline glass can further improve its mechanical properties through a chemical strengthening process.

[0093] Table 1 Batch formula, heat treatment, and crystal form parameters of the microcrystalline glass substrate

[0094]

[0095]

[0096] Table 2 Etching process of the microcrystalline glass substrate

[0097] Example 1 Example 2 Example 3 Example 4 Example 5 Hydrofluoric acid / % 3.4 4.2 3.8 4.6 3.5 Silicon dioxide / % 3.5 3.9 4.1 4.4 2.2 Barium sulfate / % 1.4 1.7 1.3 1.8 1.5 Sodium carboxymethyl cellulose / % 1.2 2.4 1.7 2.3 2.6 Pure water / % 90.5 87.8 89.1 86.9 90.2 Total 100 100 100 100 100 Etching temperature / °C 26±2 22±2 25±2 35±2 31±2 Etching time / min 175 186 180 171 173

[0098] Table 3 Moth-eye structure parameters and performance

[0099] Example 1 Example 2 Example 3 Example 4 Example 5 Moth-eye height / nm 10.1～43.6 11.2～62.8 10.2～47.1 10.8～53.3 11.4～59.5 Bottom diameter / nm 21.1～67.2 11.3～35.9 15.4～56.7 20.8～61.1 13.1～47.2 Spacing / nm 19.4～51.7 25.6～67.1 12.3～43.6 20.9～63.2 15.5～48.4 Average transmittance TrA / % 96.8 97.6 97.3 97.8 96.4 Highest transmittance TrM / % 98.3 98.9 98.6 98.7 98.2 Average reflectance ReA / % 2.3 2.1 2.2 2.2 2.4 Lowest reflectance ReM / % 1.95 1.88 1.87 1.88 1.95

[0100] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or changes can be made according to the above description, and all such improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims

1. A nepheline glass-ceramics with a moth-eye-like structure, characterized in that, Comprising: A nepheline glass-ceramic base layer and a moth-eye structure-like layer, and the nepheline glass-ceramic layer and the moth-eye structure layer are an integral structure; The average transmittance TrA of the nepheline glass-ceramic with a moth-eye structure-like at a visible light wavelength of 550 nm is ≥96%, the maximum transmittance TrM is ≥98%, the average reflectance ReA is ≤2.5%, and the minimum reflectance ReM is ≤2.0%; The moth-eye structure-like is an array of arranged cones, the bottom diameter of the cone is 10 nm to 70 nm, the height is 10 nm to 70 nm, and the spacing between adjacent cones is 10 nm to 70 nm.

2. The nepheline glass-ceramics having a moth-eye-like structure according to claim 1, characterized in that, The nepheline glass-ceramic, calculated by the molar ratio of oxides, contains: SiO2: 42.00 - 52.00%, Al2O3: 16.00 - 21.00%, Na2O: 12.00 - 21.00%, ZrO2: 1.00 - 3.50%, TiO2: 0.00 - 2.00%, P2O5: 1.00 - 5.00%, CaO: 0.00 - 2.00%, Li2O: 8.00 - 16.00%, K2O: 0.00 - 2.00%, SnO2: 0.0 - 0.2%, and B2O3: 0 - 3.00%; The composition of the nepheline glass-ceramic also contains 0.1 - 0.80% of a clarifying agent, and the clarifying agent is selected from one or more of NaCl, Sb2O3, As2O3, nitrates, and sulfates; The sum of the percentages of each component of the nepheline glass-ceramic containing the clarifying agent is 100%.

3. The nepheline microcrystalline glass with a moth-eye-like structure according to any one of claims 1 to 2, characterized in that, The main crystal form of the nepheline glass-ceramic is one or more of nepheline, eucryptite, and triclinic nepheline, and the secondary crystal form is one or more of β - quartz solid solution and sodium silicate. The crystallinity of the nepheline glass-ceramic is 30 - 60%, and the average grain size is 20 - 40 nm.

4. The nepheline microcrystalline glass with a moth-eye-like structure according to claim 1, characterized in that The moth-eye structure-like layer is obtained by etching the surface of the nepheline glass-ceramic base layer with an etching solution.

5. The nepheline glass-ceramics with a moth-eye-like structure according to claim 1, characterized in that The nepheline glass-ceramic is a nepheline glass-ceramic after ion exchange chemical strengthening treatment.

6. The nepheline microcrystalline glass with a moth-eye-like structure according to claim 5, characterized in that, The temperature used for ion exchange chemical strengthening treatment is 380 - 560 °C; the molten salt used contains one or two of sodium ions, lithium ions, and potassium ions.

7. A method for preparing nepheline microcrystalline glass with a moth-eye-like structure according to any one of claims 1 to 4, characterized in that, Comprising: Mix the compounds constituting the nepheline glass-ceramic evenly, pour them into a platinum crucible, melt at a temperature of 1500 - 1650 °C, and clarify and homogenize at a temperature of 1300 - 1400 °C to obtain a molten liquid; Form the molten liquid by any one of the forming methods of roll pressing, continuous melting and casting, floating method, and overflow method, and anneal after forming to obtain a base glass; Heat the base glass at a heating rate of 1 - 10 °C / min to a nucleation temperature of 520 - 560 °C and hold for 3 - 5 hours, and then heat at a heating rate of 1 - 10 °C / min to a crystallization temperature of 620 - 690 °C and hold for 10 - 120 min to obtain a glass-ceramic; Machine process the glass-ceramic to obtain a polished glass-ceramic sheet; Immerse the polished glass-ceramic sheet in an etching solution at 20 - 30 °C for etching to obtain the nepheline glass-ceramic with a moth-eye structure-like.

8. The preparation method of nepheline glass-ceramics with a moth-eye-like structure according to claim 7, characterized in that, The etching solution, by mass percentage, comprises: 3-5% of hydrofluoric acid, 2-5% of silicon dioxide, 1-2% of barium sulfate, 1-3% of sodium carboxymethyl cellulose, and 85-91% of pure water.

9. The nepheline microcrystalline glass with a moth-eye structure according to any one of claims 1 to 7, or the nepheline microcrystalline glass with a moth-eye structure prepared by the preparation method according to any one of claims 7 to 8, is used as a material for preparing a cover plate of a display device.

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