Lithium-aluminum-silicon glass ceramic and preparation method therefor

Abstract

Lithium-aluminum-silicon glass ceramic and a preparation method therefor. The addition of a V2O5 and Ta2O5 composite nucleating agent reduces the crystallization temperature of glass and improves the stability of the glass; a doping agent, such as CeO2, significantly accelerates the growth speed of crystals, thereby nucleating and crystallizing the glass at relatively low temperatures and improving the transmittance of the glass; a co-solvent, such as B2O3, reduces the high-temperature viscosity of the glass, thereby reducing the activation free energy during the glass crystallization process and facilitating the crystallization and processing molding; a 3D hot bending process comprises the stages of preheating, pressurizing, annealing and cooling, a copper mold transfers heat to the glass by means of heat conduction, such that the glass is evenly heated during the heating process, and natural cooling can prevent the problem of glass being broken or having an inaccurate dimensional accuracy caused by excessive fast cooling; and the graft modification on the surface of the glass significantly improves the hydrophobic property of the glass, such that the comprehensive performance of the glass is good.

Description

Lithium aluminum silicon glass-ceramics and preparation method thereof Technical Field

[0001] The present invention relates to the technical field of microcrystalline glass, and in particular to a lithium aluminum silicon microcrystalline glass and a preparation method thereof. Background Art

[0002] Glass-ceramics, also known as glass-ceramics, consists of a microcrystalline phase and a glass phase, possessing the dual properties of both glass and ceramics. Consequently, glass-ceramics are widely used in daily life. However, traditional glass is brittle and prone to microcracks, making its actual mechanical strength lower than its theoretical strength, thus limiting its application in some fields. With the increasing popularity of electronic products, the demand for glass transparency is becoming increasingly stringent. Therefore, glass-ceramics must possess both high optical transmittance and high mechanical strength. Therefore, modifying glass-ceramics to meet its application in electronic products has become a pressing issue for technical personnel.

[0003] Lithium aluminosilicate glass is made by melting SiO2, Al2O3, and Li2O as its main components, with a certain amount of auxiliary ingredients such as nucleating agents and solvents added. The main components are the basis for preparing microcrystalline glass, while the auxiliary ingredients are used to adjust the properties of the glass. Therefore, to obtain microcrystalline glass with ideal physical properties, it is necessary to strictly control the ratio of each component and the content of the auxiliary ingredients. Patent CN102167507B discloses thin lithium aluminosilicate glass for 3D tight molding. The corresponding raw materials such as SiO2, Al2O3, and Li2O are mixed, melted in a platinum crucible and kept warm, then clarified. The glass melt is poured into a cold stainless steel mold to produce a bulk glass. The glass is then annealed, cut, edge-grinded, and finely planed to the required sample size. The result is a glass that can be chemically tempered and easily 3D molded. However, simple cutting and edge grinding cannot meet the requirements of 3D molding precision. Moreover, tensile stress is formed in the center of the glass during pressing. Excessive tensile stress increases the risk of glass breakage. The present invention adjusts the ratio of the main components and auxiliary components of the lithium aluminosilicate glass, performs 3D hot bending on the glass, and then performs surface modification, so that the prepared glass has high mechanical strength and transmittance.

[0004] Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a lithium aluminum silicon microcrystalline glass and a preparation method thereof, which solves the problems of insufficient strength and low transmittance of the lithium aluminum silicon microcrystalline glass.

[0006] The technical solution of the present invention is:

[0007] A method for preparing lithium aluminum silicate glass-ceramics, the glass-ceramics comprising the following components: 55-75 parts by weight of SiO2, 1-12 parts of Al2O3, 9-15 parts of Li2O, 2-6 parts of P2O5, 3-12 parts of ZrO2, 3-6 parts of a composite nucleating agent, 0.1-8 parts of Na2O, 0.1-0.2 parts of K2O, 0.2-0.3 parts of ZnO, 0.1-0.3 parts of MgO, 2-10 parts of CaO, 1-3 parts of B2O3, 2-5 parts of Y2O3, 0.01-0.5 parts of a clarifier, 0.3-0.9 parts of a dopant, and 0.4-1.6 parts of a solvent; the preparation method is carried out according to the following steps:

[0008] (1) After the above glass components are fully mixed, they are placed in a corundum crucible, heated to 1600-1650°C at 5-10°C / min in a silicon-molybdenum furnace and melted for 3-7 hours. After clarification, the glass liquid is cast on a preheated copper mold, and the formed glass is placed in a muffle furnace at 550-600°C and kept warm for 1-3 hours for annealing and cooling to obtain a basic glass; the basic glass is heated to 580-600°C at 5-10°C / min, kept warm for 2-3 hours for nucleation, and then heated to 700-750°C at 10-15°C, kept warm for 2-4 hours for crystallization to obtain a basic microcrystalline glass.

[0009] (2) A heating tube with a diameter of 15-20 mm and a power of 10-15 kW is used for interference fit on the upper and lower heating plates for heating, and the basic microcrystalline glass is placed in a copper mold. Four groups of molding temperatures are set respectively, and the copper mold containing the basic glass is kept warm at different molding temperatures to keep the temperature inside the glass uniform. First, the upper and lower heating plates are heated to the first group of molding temperatures and kept warm for a certain period of time. Then, the copper mold is moved to the heating and forming area, heated to the second group of molding temperatures, kept warm for a certain period of time, and vacuumed to obtain curved glass; then the copper mold is moved to the first annealing area, cooled to the third group of molding temperatures, and kept warm for a period of time; finally, the mold is moved to the hot pressing molding area, heated to the fourth group of molding temperatures, and kept warm for a period of time. At the preset pressure and molding rate, the upper and lower molds are moved in unison, and hot pressing molding is performed in a nitrogen atmosphere, and the temperature is naturally cooled to obtain lithium aluminum silicon microcrystalline glass.

[0010] Furthermore, in the step (1), the composite nucleating agent is V2O5 and Ta2O5, and the mass ratio is V2O5:Ta2O5=1-1.5:2-4.5.

[0011] Furthermore, the clarifier in step (1) is any one of Sb2O3, SnO2 or Fe2O3.

[0012] Furthermore, the dopant in step (1) is any one of Nd2O3, Sm2O3 or CeO2.

[0013] Furthermore, the co-solvent in step (1) is B2O3.

[0014] Furthermore, in step (2), the four groups of molding temperatures are 720-770°C, 700-750°C, 680-730°C and 750-810°C respectively.

[0015] Furthermore, in step (2), the first group's holding time is 60-150 s, the second group's holding time is 50-150 s, the third group's holding time is 80-160 s, and the fourth group's holding time is 90-150 s.

[0016] Furthermore, in step (2), the preset pressure is 0.3-0.5 MPa, and the preset molding rate is 1.25-1.75 mm / min.

[0017] Furthermore, a modification method of the lithium aluminum silicon glass-ceramics obtained by the preparation method according to any one of claims 1 to 8 is provided, wherein the modification method comprises:

[0018] S1. Wipe both sides of the lithium aluminum silicate glass-ceramics with absorbent cotton soaked in ethanol, cut into a certain size, ultrasonically treat in a beaker containing deionized water, ethanol and acetone for 15-25 minutes, blow dry with nitrogen, and then place in a solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 5-7:3. Then soak in a water bath at 90-100℃ for 1-3 hours, take out the lithium aluminum silicate glass-ceramics, wash with deionized water, and dry to obtain surface hydroxylated glass.

[0019] S2. Immerse the surface hydroxylated glass-ceramics in a toluene solution of trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane at a certain concentration, adjust the pH to 3-5 with acetic acid, let it stand for 24-36 hours, wash with ethanol, and dry to obtain modified lithium aluminum silicon glass-ceramics.

[0020] Furthermore, in step S2, the concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane is 0.8-1.6 mg / mL.

[0021] Furthermore, a lithium aluminum silicate glass-ceramic may also include the following raw materials in parts by weight: 55-75 parts SiO2, 1-12 parts Al2O3, 9-15 parts LiO2, 2-6 parts P2O5, 3-12 parts ZrO2, 0.1-8 parts Na2O, 0-0.5 parts K2O, 0-0.5 parts ZnO, 0-0.5 parts MgO, 0-10 parts CaO, 0-3 parts B2O3, 0-5 parts Y2O3, 0.01-0.5% Sb2O3, and 0.01-0.5% SnO2. The lithium disilicate content in the glass-ceramic crystalline phase is ≥20%. The lithium disilicate crystal content is determined by X-ray diffractometer testing. The test results are analyzed by comparing with standard PDF cards to determine the corresponding crystalline phase in the glass-ceramic, and the corresponding crystallinity is calculated.

[0022] Furthermore, the transmittance of the lithium aluminum silicon glass-ceramics in the ultraviolet-visible light range of 200-800nm ​​at a thickness of 2mm can reach up to 85.3%. In some embodiments, the transmittance of the ultraviolet-visible light in the wavelength range of 200-800nm ​​is 73%-85%.

[0023] Furthermore, the corrosion resistance of the lithium aluminum silicate glass-ceramics is tested in 20% by mass sodium hydroxide and sulfuric acid solutions respectively: the alkaline weight loss rate of the lithium aluminum silicate glass-ceramics does not exceed 0.9%, and the acidic weight loss rate does not exceed 1.95%, wherein the weight loss rate = (initial mass of the glass sample - mass of the glass sample after corrosion) / initial mass of the glass sample; in some embodiments, the alkaline weight loss rate of the lithium aluminum silicate glass-ceramics is 0.6%-0.9%, and the acidic weight loss rate is 1%-1.95%.

[0024] Furthermore, the flexural strength of the lithium aluminum silicon glass-ceramics is not less than 90 MPa. In some embodiments, the flexural strength is 90-96 MPa.

[0025] Furthermore, the lithium aluminum silicon glass-ceramics has good hydrophobicity. The hydrophobicity of the glass surface was tested using an optical contact angle meter. The contact angles at three different positions of the glass were tested and the average value was taken. The contact angle was 97°-122°.

[0026] The beneficial technical effects of the present invention are:

[0027] (1) The present invention first adjusts the proportion of the main components in the lithium aluminum silicate glass-ceramics, and then adds auxiliary components such as a clarifier, a composite nucleating agent, a dopant and a cosolvent on the basis of ensuring the glass-ceramic network structure, so that the components play a synergistic role. Then, the glass is subjected to multiple procedures of 3D hot bending treatment to improve the flexural strength. Finally, the surface of the lithium aluminum silicate glass is modified, and the obtained lithium aluminum silicate glass has good hydrophobicity.

[0028] (2) Adding V2O5 and Ta2O5 composite nucleating agents reduces the crystallization temperature of the glass and improves the stability of the glass. Adding clarifiers such as Sb2O3, SnO2 and Fe2O3 absorbs oxygen at low temperatures and decomposes and releases oxygen at high temperatures, which plays a clarifying role. The addition of solvent B2O3 reduces the high-temperature viscosity of the glass, which reduces the activation free energy in the crystallization process and is conducive to crystallization and processing. Adding dopants such as Nd2O3, Sm2O3 and CeO2 significantly accelerates the crystal growth rate, allowing the glass to nucleate and crystallize at a lower temperature. Ce 4+ ions and Nd 3+ The ions are network interstitial ions. The pinning effect of the ions makes the glass network tighter, diffusion more difficult, and has a certain refinement effect on the grains, thereby improving the thermal stability of the microcrystalline glass and increasing the transmittance of the glass.

[0029] (3) The 3D hot bending process goes through the preheating, pressurizing, annealing and natural cooling stages. The copper mold transfers heat to the glass through heat conduction, so that the glass is heated evenly during the heating process and the temperature difference is small. The natural cooling method is used for cooling, which can reduce the internal stress of the finished glass caused by the molding rate problem and prevent the breakage or dimensional accuracy problems caused by excessive cooling. The glass surface is grafted and modified, which significantly improves the hydrophobicity of the glass, making the prepared lithium aluminum silicon microcrystalline glass have excellent comprehensive performance. DETAILED DESCRIPTION

[0030] In order to better understand the technical solutions of the present invention, the following is a further detailed description of the above content of the present invention through specific implementation methods in the form of examples. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0031] Example 1

[0032] (1) 75 parts of SiO2, 1 part of Al2O3, 10 parts of Li2O, 3 parts of P2O5, 5 parts of ZrO2, 1.2 parts of V2O5, 2.3 parts of Ta2O5, 0.9 parts of Na2O, 0.1 parts of K2O, 0.25 parts of ZnO, 0.15 parts of MgO, 8 parts of CaO, 3 parts of B2O3, 2 parts of Y2O3, 0.2 parts of Sb2O3, 0.7 parts of CeO2 and 0.4 parts of B2O3 were mixed thoroughly. After homogenization, place it in a corundum crucible, heat it to 1620℃ at 8℃ / min in a silicon-molybdenum furnace and melt it for 5h. After clarification, cast the glass liquid on a preheated copper mold, and put the formed glass into a muffle furnace at 560℃ and keep it warm for 2h for annealing and cooling to obtain basic glass; heat the basic glass to 600℃ at 5℃ / min, keep it warm for 3h for nucleation, and then heat it to 720℃ at 125℃ and keep it warm for 4h for crystallization to obtain basic microcrystalline glass.

[0033] (2) A heating tube with a diameter of 15 mm and a power of 12 kW was used to heat the upper and lower heating plates by interference fit. The basic microcrystalline glass was placed in a copper mold. Four sets of molding temperatures were set respectively. The copper mold containing the basic glass was kept warm at different molding temperatures to keep the temperature inside the glass uniform. First, the upper and lower heating plates were heated to 730 ° C and kept warm for 80 seconds. Then, the copper mold was moved to the heating molding area, heated to 750 ° C, kept warm for 110 seconds, and vacuumed to obtain curved glass. Then, the copper mold was moved to the first annealing area, cooled to 720 ° C, and kept warm for 150 seconds. Finally, the mold was moved to the hot pressing molding area, heated to 800 ° C, and kept warm for 120 seconds. At a preset pressure of 0.5 MPa and a molding rate of 1.5 mm / min, the upper and lower molds were fitted and hot pressed in a nitrogen atmosphere. The mold was naturally cooled to obtain lithium aluminum silicon microcrystalline glass.

[0034] (3) Wipe both sides of the lithium aluminum silicate glass-ceramics with cotton wool soaked in ethanol, cut into a certain size, ultrasonically treat for 25 minutes in a beaker containing deionized water, ethanol and acetone, blow dry with nitrogen, and then place in a solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 6:3. Then soak in a water bath at 95°C for 3 hours, take out the lithium aluminum silicate glass-ceramics, wash with deionized water, and dry to obtain surface hydroxylated glass.

[0035] (4) The surface hydroxylated glass-ceramics was immersed in a toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane with a concentration of 0.8 mg / mL, and the pH was adjusted to 4 with acetic acid. After standing for 32 hours, the glass-ceramics was washed with ethanol and dried to obtain modified lithium aluminum silicate glass-ceramics.

[0036] Example 2

[0037] The difference between this embodiment and embodiment 1 is that in step (1), SiO2 is 72 parts and Al2O3 is 4 parts, and other conditions remain unchanged.

[0038] Example 3

[0039] The difference between this embodiment and embodiment 1 is that in step (1), SiO2 is 69 parts and Al2O3 is 7 parts, and other conditions remain unchanged.

[0040] Example 4

[0041] The difference between this embodiment and embodiment 1 is that in step (1), SiO2 is 66 parts and Al2O3 is 10 parts, and other conditions remain unchanged.

[0042] Example 5

[0043] The difference between this embodiment and embodiment 1 is that in step (1), SiO2 is 64 parts and Al2O3 is 12 parts, and other conditions remain unchanged.

[0044] Example 6

[0045] (1) 66 parts of SiO2, 10 parts of Al2O3, 12 parts of Li2O, 5 parts of P2O5, 4 parts of ZrO2, 1.3 parts of V2O5, 4.2 parts of Ta2O5, 2.5 parts of Na2O, 0.2 parts of K2O, 0.2 parts of ZnO, 0.3 parts of MgO, 6 parts of CaO, 2 parts of B2O3, 3.5 parts of Y2O3, 0.3 parts of Sb2O3, 0.5 parts of CeO2 and 0.4 parts of B2O3 were mixed thoroughly. After homogenization, place it in a corundum crucible, heat it to 1650℃ in a silicon-molybdenum furnace at 10℃ / min and melt it for 6h. After clarification, cast the glass liquid on a preheated copper mold, and put the formed glass into a muffle furnace at 600℃ and keep it warm for 1h for annealing and cooling to obtain basic glass; heat the basic glass to 580℃ at 10℃ / min, keep it warm for 3h for nucleation, and then heat it to 740℃ at 12℃ and keep it warm for 3h for crystallization to obtain basic microcrystalline glass.

[0046] (2) A heating tube with a diameter of 20 mm and a power of 13 kW was used to heat the upper and lower heating plates through interference fit. The basic microcrystalline glass was placed in a copper mold. Four sets of molding temperatures were set respectively. The copper mold containing the basic glass was kept warm at different molding temperatures to keep the temperature inside the glass uniform. First, the upper and lower heating plates were heated to 730 ° C and kept warm for 90 seconds. Then, the copper mold was moved to the heating molding area, heated to 750 ° C, kept warm for 130 seconds, and vacuumed to obtain curved glass. Then, the copper mold was moved to the first annealing area, cooled to 690 ° C, and kept warm for 140 seconds. Finally, the mold was moved to the hot pressing molding area, heated to 780 ° C, and kept warm for 100 seconds. At a preset pressure of 0.4 MPa and a molding rate of 1.75 mm / min, the upper and lower molds were fitted and moved. Hot pressing molding was carried out in a nitrogen atmosphere, and the temperature was naturally cooled to obtain lithium aluminum silicon microcrystalline glass.

[0047] (3) Wipe both sides of the lithium aluminum silicate glass-ceramics with absorbent cotton soaked in ethanol, cut into a certain size, ultrasonically treat for 20 minutes in a beaker containing deionized water, ethanol and acetone, blow dry with nitrogen, and then place in a solution of 98% concentrated sulfuric acid and 30% hydrogen peroxide with a volume ratio of 7:3. Then soak in a water bath at 100°C for 2 hours, take out the lithium aluminum silicate glass-ceramics, wash with deionized water, and dry to obtain surface hydroxylated glass.

[0048] (4) The surface hydroxylated glass-ceramics was immersed in a toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane with a concentration of 0.8 mg / mL, and the pH was adjusted to 5 with acetic acid. After standing for 24 hours, the glass-ceramics was washed with ethanol and dried to obtain modified lithium aluminum silicate glass-ceramics.

[0049] Example 7

[0050] The difference between this embodiment and embodiment 6 is that the cosolvent in step (1) is 0.7 parts of B2O3, and other conditions remain unchanged.

[0051] Example 8

[0052] The difference between this embodiment and embodiment 6 is that the cosolvent in step (1) is 1.0 part of B2O3, and other conditions remain unchanged.

[0053] Example 9

[0054] The difference between this embodiment and embodiment 6 is that the cosolvent in step (1) is 1.3 parts of B2O3, and other conditions remain unchanged.

[0055] Example 10

[0056] The difference between this embodiment and embodiment 6 is that the cosolvent in step (1) is 1.6 parts of B2O3, and other conditions remain unchanged.

[0057] Example 11

[0058] The difference between this embodiment and embodiment 6 is that the concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane in step (4) is 1.0 mg / mL.

[0059] Example 12

[0060] The difference between this embodiment and embodiment 6 is that the concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane in step (4) is 1.2 mg / mL.

[0061] Example 13

[0062] The difference between this embodiment and embodiment 6 is that the concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane in step (4) is 1.4 mg / mL.

[0063] Example 14

[0064] The difference between this embodiment and embodiment 6 is that the concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane in step (4) is 1.6 mg / mL.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 6 is that the composite nucleating agents V2O5 and Ta2O5 are not added in step (1), and other conditions remain unchanged.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 6 is that the clarifier Sb2O3 is not added in step (1), and other conditions remain unchanged.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 6 is that the dopant CeO2 is not added in step (1), and other conditions remain unchanged.

[0071] Comparative Example 4

[0072] The difference between this comparative example and Example 6 is that no co-solvent B2O3 is added in step (1), and other conditions remain unchanged.

[0073] Comparative Example 5

[0074] The difference between this comparative example and Example 6 is that the basic microcrystalline glass obtained in step (1) is not subjected to the next step of heat bending treatment.

[0075] Comparative Example 6

[0076] The difference between this comparative example and Example 6 is that the lithium aluminum silicon glass-ceramics obtained in step (2) is not subjected to surface modification treatment.

[0077] Transmittance test: polish both sides of the glass sample to a thickness of 2 mm, and use a spectrophotometer to test the ultraviolet-visible light transmittance (or transmittance) of the glass in the range of 200-800 nm.

[0078] Glass transition temperature (T g ) Test: The glass transition temperature was tested using a differential thermal analyzer at a heating rate of 10°C / min.

[0079] Table 1: Lithium aluminum silicon glass ceramic test table

[0080] As can be seen from the above table, with the increase of Al2O3 content in lithium aluminum silicon glass-ceramics, the content of SiO2 is appropriately reduced under the condition of ensuring the formation of glass network, because when the content of SiO2 is too much, it will lead to difficulties in melting and forming the glass; in Example 4, when the addition amount of SiO2 is 66 parts and Al2O3 is 10 parts, the transmittance of the sample reaches a maximum of 85.3%, indicating that the transmittance of the glass is better at this time. This is because the ultraviolet absorption of the glass is mainly caused by the excitation of the extranuclear electrons of oxygen ions absorbing photons, and Al2O3 helps to improve the chemical stability of the glass; in Comparative Example 1, no composite nucleating agent is added, resulting in a glass transmittance of only 55.1%. The addition of composite nucleating agent is beneficial to the crystallization of glass and increases the transparency; in comparative example 2, no clarifier is added, and the transmittance is 61.0%. The clarifier Sb2O3 and the like play a clarifying role in the system, absorbing oxygen at low temperature and decomposing and releasing oxygen at high temperature. Since the clarification temperatures of Sb2O3, SnO2 and Fe2O3 are different, the composite clarifier composed of them can play a better clarifying role, thereby improving the transmittance of the glass; in comparative example 3, no dopant is added, and the transmittance is 63.1%. The dopant CeO2 and the like makes the glass network tight, diffusion more difficult, has a certain refining effect on the grains, improves the thermal stability of the microcrystalline glass, and improves the transmittance of the glass.

[0081] The glass transition temperature increases with the increase of Al2O3 content. This is because the increase in chemical bond energy in the glass structure strengthens the glass structure, thereby improving the stability of the glass. The Tg of Comparative Example 1 is 645.2°C. This is because the composite nucleating agent of V2O5 and Ta2O5 can reduce the forming ability of the glass, increase the glass transition temperature, promote crystallization, and make the glass structure tight and firm.

[0082] Acid and alkali resistance test: Prepare a 20% by mass solution of NaOH and H2SO4, place the glass sample in the solution and corrode for 12 hours, take it out and weigh it, and use the weight loss method to determine the acid and alkali resistance of the sample.

[0083] Weight loss rate = (initial mass of glass sample - mass of glass sample after corrosion) / initial mass of glass sample.

[0084] Table 2: Lithium aluminum silicon glass-ceramic test table

[0085] High temperature viscosity test: Use a high temperature viscometer to test the glass's high temperature viscosity at 1300°C.

[0086] Table 3: High temperature viscosity test table

[0087] It can be seen from the data in the above table that with the increase of the boron content in the lithium aluminum silicon microcrystalline glass, the high-temperature viscosity of the glass gradually decreases. Comparative Example 4 does not contain a co-solvent and has a viscosity of 738.3 dPa·s, while in Example 10, when the amount of boron added is 1.6 parts, the viscosity is reduced to 420.2 dPa·s, indicating that the introduction of boron can significantly reduce the high-temperature viscosity of the glass. This is because B2O3 replaces silicon oxide tetrahedron [SiO4] in the form of [BO3], that is, boron ions can replace oxygen ions in the glass network structure, causing large silicon oxide tetrahedrons in the glass system to depolymerize, resulting in the matrix glass structure becoming loose and the network connection degree being reduced, thereby reducing the viscosity and melting temperature, which is beneficial to the glass forming process.

[0088] Flexural strength test: A material testing machine is used to test the flexural strength of the glass.

[0089] Table 4: Flexural strength test table

[0090] The 3D glass hot bending process is to place the cut glass between the arc-shaped molds of the hot bending machine, heat it to a certain temperature in sequence through several workstations to soften the glass, soften the glass under a certain pressure so that it gradually fits the mold, and then cold-cut it by maintaining pressure and gradually cooling it to obtain 3D shaped glass; Comparative Example 5 did not undergo 3D hot bending treatment, and the flexural strength of the glass was only 52.1 MPa, while the flexural strengths of Examples 1-5 were all above 90 MPa, indicating that the hot bending process can significantly improve the strength of the glass; in addition, Al2O3 is an important component for preparing high-strength and high-hardness glass. Therefore, as the Al2O3 content increases, the glass has more space as a channel for ion exchange, and the glass strength is increased.

[0091] Contact angle test: Use an optical contact angle meter to test the hydrophobicity of the glass surface. Test the contact angles at three different positions on the glass and take the average value.

[0092] Table 5: Contact angle test table

[0093] The monomer containing fluorine is a material with very low surface energy. As the concentration of fluorine-containing monomer on the surface of lithium aluminum silicon glass-ceramics increases, the grafting rate of fluorine monomer on glass increases, thereby increasing the contact angle of the glass surface and enhancing the hydrophobicity. In Example 6, the glass surface was not fluorine-modified, and its contact angle was 84.2°, while the contact angle of Example 14 reached 122.0°, so the hydrophobicity of the glass was greatly improved. Although the above describes the specific embodiments of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for preparing lithium aluminum silicon glass-ceramics, characterized in that: The microcrystalline glass comprises the following components: 55-75 parts by weight of SiO2, 1-12 parts of Al2O3, 9-15 parts of Li2O, 2-6 parts of P2O5, 3-12 parts of ZrO2, 3-6 parts of composite nucleating agent, 0.1-8 parts of Na2O, 0.1-0.2 parts of K2O, 0.2-0.3 parts of ZnO, 0.1-0.3 parts of MgO, 2-10 parts of CaO, 1-3 parts of B2O3, 2-5 parts of Y2O3, 0.01-0.5 parts of clarifier, 0.3-0.9 parts of dopant and 0.4-1.6 parts of solvent; the preparation method is carried out according to the following steps: Step (1) After the above-mentioned microcrystalline glass components are fully mixed and uniformly mixed, the mixture is placed in a corundum crucible, and the temperature is increased to 1600-1650°C at 5-10°C / min in a silicon-molybdenum furnace for melting for 3-7h. After clarification, the glass liquid is cast on a preheated copper mold, and the formed glass is placed in a muffle furnace at 550-600°C for 1-3h for annealing and cooling to obtain a basic glass; the basic glass is heated to 580-600°C at 5-10°C / min, and kept warm for 2-3h for nucleation, and then the temperature is increased to 700-750°C at 10-15°C, and kept warm for 2-4h for crystallization to obtain a basic microcrystalline glass; Step (2) uses a heating tube with a diameter of 15-20mm and a power of 10-15kW to heat on the upper and lower heating plates with interference fit, places the basic microcrystalline glass in a copper mold, sets 4 groups of molding temperatures respectively, and keeps the copper mold containing the basic glass at different molding temperatures to keep the temperature inside the glass uniform. First, the upper and lower heating plates are heated to the first group of molding temperatures and kept warm for a certain period of time. Then, the copper mold is moved to the heating molding area, heated to the second group of molding temperatures, kept warm for a certain period of time, and evacuated to obtain curved glass; then the copper mold is moved to the first annealing area, cooled to the third group of molding temperatures, and kept warm for a period of time; finally, the mold is moved to the hot pressing molding area, heated to the fourth group of molding temperatures, and kept warm for a period of time. At the preset pressure and molding rate, the upper and lower molds are moved in unison, and hot pressing molding is performed in a nitrogen atmosphere, and the temperature is naturally cooled to obtain lithium aluminum silicon microcrystalline glass.

2. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: In the step (1), the composite nucleating agent is V2O5 and Ta2O5, and the mass ratio is V2O5:Ta2O5=1-1.5:2-4.

5.

3. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: In the step (1), the clarifier is any one of Sb2O3, SnO2 or Fe2O3.

4. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: The dopant in step (1) is any one of Nd2O3, Sm2O3 or CeO2.

5. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: The co-solvent in step (1) is B2O3.

6. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: The four groups of molding temperatures in step (2) are 720-770°C, 700-750°C, 680-730°C and 750-810°C respectively.

7. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: In the step (2), the insulation time of the first group is 60-150s, the insulation time of the second group is 50-150s, the insulation time of the third group is 80-160s, and the insulation time of the fourth group is 90-150s.

8. The method for preparing lithium aluminum silicon glass-ceramics according to claim 1, characterized in that: In the step (2), the preset pressure is 0.3-0.5 MPa, and the preset molding speed is 1.25-1.75 mm / min.

9. A method for modifying lithium aluminum silicon glass-ceramics obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The modification method is: S1. Wipe both sides of the lithium aluminum silicon glass-ceramics with absorbent cotton soaked in ethanol, cut into a certain size, ultrasonicate in a beaker containing deionized water, ethanol and acetone for 15-25 minutes, blow dry with nitrogen, and then place in a 98% concentrated sulfuric acid and 30% hydrogen peroxide solution with a volume ratio of 5-7:3, and then soak in a water bath at 90-100°C for 1-3 hours, take out the lithium aluminum silicon glass-ceramics, wash with deionized water, and dry to obtain surface hydroxylated glass; S2. Immerse the surface hydroxylated glass-ceramics in a toluene solution of trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane at a certain concentration, adjust the pH to 3-5 with acetic acid, let it stand for 24-36 hours, wash with ethanol, and dry to obtain modified lithium aluminum silicon glass-ceramics.

10. The method for modifying lithium aluminum silicon glass-ceramics according to claim 9, characterized in that: The concentration of the toluene solution of trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane in step (2) is 0.8-1.6 mg / mL.

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