Preparation method of high-strength high-transmittance zero-expansion microcrystalline glass and product thereof

Abstract

The application discloses a preparation method of high-strength high-transmittance zero-expansion microcrystalline glass and a product, and belongs to the technical field of microcrystalline glass. The microcrystalline glass is composed of lithium-aluminum silicate, contains crystals and residual glass phases, and the raw material component range contains, in percentage by weight and in terms of oxides, 50% to 70% of SiO2, 25% to 40% of Al2O3, 2% to 10% of Li2O, 1% to 10% of P2O5, 0.5% to 5% of MgO, 0.5% to 5% of ZnO, 0 to 5% of K2O, 0 to 5% of Na2O, 0.5% to 5% of TiO2, 0.5% to 5% of ZrO2, 0.5% to 2% of a clarifying agent, and 0 to 2% of other components. The microcrystalline glass has the characteristics of high strength, high transmittance and near zero expansion, solves the problem that the prior art is difficult to consider high strength and transmittance, and meets the use requirements of high-end fields such as aviation, spaceflight and a photolithography machine.

Description

Technical Field

[0001] This invention relates to the field of glass-ceramic technology, and in particular to a method and product for preparing high-strength, high-transmittance, zero-expansion glass-ceramic. Background Technology

[0002] Zero-expansion glass-ceramics, also known as "glass-ceramics," are a type of glass material whose macroscopic coefficient of thermal expansion approaches zero through a controlled crystallization process that precipitates specific functional crystalline phases within the glass matrix. They combine the formability and translucency of glass with the structural stability of crystals, effectively suppressing thermal deformation and thermal stress cracking under drastic temperature changes. This makes them a core material in high-end fields such as aerospace, precision instruments, and semiconductor equipment. In semiconductor manufacturing, the stage and wafer transport device of lithography machines need to maintain micron-level precision during repeated heating and cooling cycles; zero-expansion materials are the core foundation for ensuring the reliability of equipment operation.

[0003] Zero-expansion glass-ceramics are typically represented by lithium aluminum silicate systems. This system achieves zero expansion by precipitating within the glass matrix. β Quartz solid solution utilizes the negative thermal expansion characteristics of the crystalline phase to counteract the positive thermal expansion effect of the glass matrix, thereby achieving near-zero expansion of the overall material. After decades of development, lithium aluminum silicon (LiSi)-based zero-expansion microcrystalline glass has achieved industrial application, but many technical bottlenecks still need to be addressed in its practical promotion. First, insufficient strength performance is the core problem restricting its application range. The bending strength of traditional LiSi microcrystalline glass is usually between 100 and 150 MPa, and it is prone to brittle fracture under impact loads or complex stresses, making it difficult to meet the design requirements of lightweight and high load-bearing capacity for aerospace components. The root cause of this defect lies in the disordered growth and distribution of the crystalline phase during crystallization, as well as the stress concentration at the interface between the glass matrix and the crystalline phase. At the same time, the unavoidable microcracks and pores inside the material also become sources of stress diffusion. Second, optical transmittance needs to be improved. With the trend of integrated and miniaturized optical devices, zero-expansion microcrystalline glass not only needs to meet the requirements of dimensional stability, but also needs to have excellent light transmittance to adapt to functions such as optical imaging and laser transmission. However, during the preparation process of traditional lithium aluminum silicon microcrystalline glass, due to the control of crystallization and the influence of factors such as formulation and environment, the glass exhibits a certain depth of pale yellow or brownish-yellow color, resulting in a transmittance of less than 90% (10 mm thickness), which cannot meet the application standards of optical components.

[0004] In recent years, scholars both domestically and internationally have conducted extensive research on the performance optimization of lithium aluminum silicon microcrystalline glass. Regarding strength improvement, research approaches have mainly focused on two directions: crystal phase control and interface modification. This involves introducing nucleating agents such as ZrO2 and P2O5 to promote the precipitation of fine and uniform particles in the glass matrix. β- Quartz solid solution crystal phase: reducing the crystal phase grain size to decrease stress concentration; by adding oxides such as MgO and ZnO, the interfacial compatibility between the glass matrix and the crystal phase is optimized, alleviating interfacial stress. Regarding the improvement of light transmittance, the research focuses on controlling the crystal phase grain size and distribution. By precisely controlling the nucleation temperature and time, the crystal phase grain size is controlled within the range of 20–50 nm, making it much smaller than the wavelength of visible light, thereby avoiding light scattering.

[0005] For example, Chinese invention patent CN108821595A discloses a high-hardness, zero-expansion transparent microcrystalline glass and its preparation method. The glass composition, based on the molar percentage of oxides, is as follows: 58.0%~72.0% SiO2, 10.0%~16.0% Al2O3, 5.0%~15.0% Li2O, 1.0%~8.0% (MgO+ZnO), 1.0%~3.0% TiO2, 0.5%~3.0% ZrO2, 0.01%~2.0% P2O5, and 0.1%~1.0% Sb2O3, with the sum of the molar masses of each oxide satisfying 100%. This invention's high-hardness, zero-expansion transparent microcrystalline glass, based on... β - Quartz solid solution is the main crystalline phase, with a grain size of 10~50 nm, and the absolute value of its coefficient of thermal expansion in the temperature range of 20~700℃ is not greater than 0.12×10⁻⁶. -6 ℃ -1 The microhardness can reach 8.5 GPa, and the sample showed no cracks after 10 thermal shock resistance tests. The visible light transmittance (2 mm) is above 86.6%. For example, Chinese invention patent CN101538118A discloses an ultra-low expansion microcrystalline glass for laser gyroscopes and its preparation method. The mass percentage composition of this microcrystalline glass is: 56%~68% SiO2, 21%~27% Al2O3, 2%~4% Li2O, 0~1% Na2O, 0~1% K2O, 0~3% MgO, 0~1.5% ZnO, 4.5%~6.8% P2O5, 1%~2.5% TiO2, 1%~2.5% ZrO2, 0.5%~1.5% Sb2O3 / As2O3; its main crystalline phase is... β - Quartz solid solution, with a crystalline phase content of 70%~85%, a grain size of less than 50 nm, and a coefficient of thermal expansion on the order of 10. -8The product has a bending strength of over 170 MPa, with an actual maximum of 210 MPa, a processing roughness better than 2, and a spectral transmittance (5 mm) of over 90% in the 0.6~2 μm band. Furthermore, Chinese invention patent CN104370470A discloses a microcrystalline glass with ultra-low coefficient of thermal expansion and high transparency, and its preparation method. The microcrystalline glass comprises, by weight percentage: 65%~69% SiO2, 19%~20% Al2O3, 3.1%~4.2% Li2O, 3%~4.5% B2O3, 0.1%~0.4% Na2O, 0.1%~0.4% K2O, 0.3%~0.5% MgO, 0.6%~1.4% BaO, 0.6%~1.4% ZnO, 1.0%~1.7% TiO2, 1.0%~1.3% ZrO2, 0.4%~0.8% P2O5, 0.3%~0.8% F, and 0.02%~0.3% CeO2; its density is 2.59 g / cm³. 3 The coefficient of thermal expansion is -1.0 to +1.0 × 10⁻⁶ at 20–800 °C. -7 / K, thermal shock temperature can reach 1000 ℃; visible light transmittance is not less than 94.0% when the thickness of the microcrystalline glass product is 4 mm; transparency remains unchanged after 1000 h of continuous use at a service temperature of 900 ℃; impact resistance index is that it does not break after being dropped three times continuously by a solid steel ball with a diameter of 2 cm and a weight of 378 g and a height of 20.0 cm.

[0006] However, existing research methods still have obvious limitations: most modification strategies can only improve a single property and it is difficult to achieve both high strength and high transmittance. For example, although the bending strength of some lithium aluminum silicon microcrystalline glass with added ZrO2 is increased to more than 200 MPa, the introduction of ZrO2 will increase the opacity of the glass, resulting in a decrease in transmittance to below 60%, which makes it difficult to meet the requirements of high transmittance (such as under the standards of GB / T 2680-2021 and GB / T 7962.1-2010, the transmittance is >90% when d=10 mm).

[0007] With the rapid development of high-end industries such as aerospace and semiconductors, the market demand for microcrystalline glass with high strength, high transmittance, and zero expansion is becoming increasingly urgent. Developing a simple, cost-effective method for preparing zero-expansion microcrystalline glass that can simultaneously improve both mechanical and optical properties is crucial. This would not only break through technological monopolies and meet the domestic production needs of high-end equipment, but also promote the widespread application of zero-expansion microcrystalline glass in civilian optical instruments, new energy equipment, and other fields, thus possessing significant scientific and engineering value. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a method and product for preparing a microcrystalline glass with high strength, high transmittance and near-zero coefficient of expansion. The technical problem to be solved is to achieve the preparation of a microcrystalline glass with high strength, high transmittance and zero coefficient of expansion through technical means such as formula design, melting process design and crystallization process design.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect of the invention, a high-strength, high-transmittance, zero-expansion microcrystalline glass is provided, said microcrystalline glass being composed of lithium aluminum silicate and comprising crystals and a residual glass phase. The raw material components, by weight percentage and based on oxides, contain: 50%–70% SiO2, 25%–40% Al2O3, 2%–10% Li2O, 1%–10% P2O5, 0.5%–5% MgO, 0.5%–5% ZnO, 0%–5% K2O, 0%–5% Na2O, 0.5%–5% TiO2, 0.5%–5% ZrO2, 0.5%–2% clarifying agent, and 0%–2% other components; the other components include one or more of Y2O3, Yb2O3, and Lu2O3; the sum of the mass percentages of all raw material components is 100%.

[0010] Preferably, in the high-strength, high-transmittance, zero-expansion microcrystalline glass, the molar percentage of oxides is SiO2:Al2O3 = 2.5~4.5; Al2O3:Li2O = 1.2~4.2.

[0011] Preferably, in the high-strength, high-transmittance, zero-expansion microcrystalline glass, the molar percentage of oxides is ZrO2:(ZrO2+TiO2)=0.2~0.5.

[0012] Preferably, in the high-strength, high-transmittance, zero-expansion microcrystalline glass, the clarifying agent includes one or more of As2O3, Sb2O3, NH4Cl, and NH4NO3.

[0013] In a second aspect of the present invention, a method for preparing the high-strength, high-transmittance, zero-expansion microcrystalline glass of the first aspect of the present invention is provided, comprising the following steps: (1) Based on the design ratio of high-strength, high-transmittance, zero-expansion microcrystalline glass, prepare raw material components to obtain glass batch; heat the glass batch to melt to form molten glass liquid; (2) The molten glass is stirred and clarified to obtain a homogeneous glass melt; (3) The homogeneous molten glass is poured into a mold of the target shape and annealed to obtain the mother glass; (4) The mother glass is subjected to nucleation and crystallization treatment to obtain high-strength, high-transmittance, zero-expansion microcrystalline glass.

[0014] Preferably, in step (1), the purity of the glass batch is ≥99.95%.

[0015] Preferably, in step (1), the melting temperature of the glass batch is 1650~1680 ℃.

[0016] Preferably, in step (2), the stirring temperature is 1650~1680 ℃ and the time is 20~60 h; the clarification temperature is 1650~1680 ℃ and the time is 20~60 h.

[0017] Preferably, in step (3), the temperature of the homogeneous glass melt is 1500~1600 ℃.

[0018] Preferably, in step (3), the mold preheating temperature is 300~1000 ℃.

[0019] Preferably, in step (3), the annealing cooling rate is ≤1.5 ℃ / h.

[0020] Preferably, in step (4), the nucleation temperature is 620~700 ℃ and the nucleation time is 10~50 h; the crystallization temperature is 720~820 ℃ and the crystallization time is 10~50 h.

[0021] In the above process, those skilled in the art can use appropriate equipment or operations according to actual conditions or needs. For example, the crucible and stirrer rotor used in melting are preferably made of platinum. During the melting process, the volume of molten glass does not exceed 4 / 5 of the crucible height. The melting process can be carried out directly from the glass batch through a single melting, or through two or more melting processes. During the two or more melting processes, the high-temperature molten glass can be rapidly cooled at low temperatures to cause cracking. The mold for the homogeneous molten glass is suitable to be made of platinum or cast iron, and the bottom mold can be air-cooled or water-cooled. Those skilled in the art can also use other suitable conventional technical means to achieve the purpose of each step.

[0022] Based on the above technical solutions, the design concept and principle of this invention are as follows: The high-strength, high-transmittance, zero-expansion microcrystalline glass of this invention is composed of lithium aluminum silicate and includes crystalline and residual glass phases. SiO2, Al2O3, and Li2O are the constituent elements of the microcrystalline glass. β- Quartz solid solution crystal phase is the main raw material, with ZrO2 and TiO2 as nucleating agents. Yttrium oxide, ytterbium oxide, and lutetium oxide are used to improve the quality of the glass, achieving high aluminum content melting to achieve high strength, high transmittance, and near-zero expansion characteristics. This invention is based on a lithium aluminum silicate system to prepare high-strength, high-transmittance, zero-expansion microcrystalline glass, designing and limiting the content range of each component. Simultaneously, the glass melting, annealing, and crystallization processes were optimized to ensure the glass is free of bubbles, streaks, impurities, and cracks. A glass with an expansion coefficient of α was prepared through crystallization. 0~50 = (0 ± 0.02) × 10 -7 / ℃), which meets the standard for zero-expansion microcrystalline glass in this field.

[0023] Corresponding to the formulation, the melting process of this invention is achieved through innovative technology. Because the alumina content in the composition design of this invention is relatively high, making glass melting difficult, the melting temperature, stirring temperature, and refining temperature are all set at 1650~1680 °C. Furthermore, the temperature and time are balanced to meet the high-temperature range that the platinum crucible can withstand. This not only improves glass quality but also reduces energy consumption and the frequency of platinum and refractory material consumption, thus enhancing its applicability in industrial applications.

[0024] It should be noted that the Al2O3 content in the existing technology (CN108821595A) is 10.0%~16.0%, and the Al2O3 content in the existing technology (CN104370470A) is 19%~20%. Both are significantly lower than the 25.0%~40.0% Al2O3 content designed in this invention, and belong to different glass systems. This invention increases the Al2O3 content to significantly improve the strength of the glass, but it also greatly increases the difficulty of glass melting. This requires higher melting temperatures and times to improve the problems of glass bubbles, streaks, and other defects caused by the high viscosity of the glass. Prolonged high-temperature melting increases the consumption of platinum crucibles, which is detrimental to furnace wear and energy consumption, and can also cause component imbalance fluctuations due to glass evaporation. Therefore, this invention specifically designs the component ratios and adds trace amounts of other components, including one or more of Y2O3, Yb2O3, and Lu2O3. The above design not only improves the melting difficulty of high-aluminum content glass but also ensures the stability of the glass composition, thereby enhancing the quality of the glass. Under the specific design of this invention, the resulting glass product possesses high strength properties that are difficult to surpass with existing technologies.

[0025] The existing technology (CN101538118A) has an Al2O3 content of 21.0%~27.0%, which slightly overlaps with the 25.0%~40.0% Al2O3 content proposed in this invention. However, the design concept of this invention differs significantly from that of the existing technology. Furthermore, the existing technology does not add trace amounts of other components as described in this invention, resulting in a lower crystallization rate and a crystalline phase content of 70%~85%, while the crystalline phase content of this invention is above 93%~98%. Therefore, the strength of the existing technology (CN101538118A) cannot achieve the effect of this invention. In the formula disclosed in the existing technology (CN104370470A), the Li2O content is significantly higher than that in this invention. Excessive Li2O leads to a decrease in glass melting temperature and crystallization temperature, and also results in... β The transformation temperature between quartz solid solution and spodumene also decreases, which is conducive to crystallization, but spodumene is more likely to precipitate, leading to excessive glass crystallization. This also fails to meet the technical objective of this invention.

[0026] Therefore, the composition design of this invention differs significantly from that of existing microcrystalline glass. Based on the goal of achieving high strength, high transmittance, and zero expansion, this solution controls the Al2O3 content within the target range of 25.0% to 40.0%, resulting in a change different from existing technologies. This solves the problem of existing technologies struggling to achieve both high strength, high transmittance, and zero expansion. The above-mentioned effects are the result of the specific design logic described above, rather than conventional practices in the field.

[0027] In summary, based on the specific component design and manufacturing process of this invention, this solution further improves the bending strength and transmittance of existing lithium aluminum silicon system zero-expansion glass-ceramics, taking into account the requirements of high strength, high transmittance, and zero expansion, thus outperforming the performance of existing glass-ceramics. As presented in one or more embodiments of this invention, the manufactured high-strength, high-transmittance, zero-expansion glass-ceramics has a bending strength greater than 225 MPa and can also achieve an excellent transmittance of greater than 90% (d=10 mm, λ=500 nm).

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides a high-strength, high-transmittance, zero-expansion microcrystalline glass. Under the condition of meeting the standard of zero-expansion microcrystalline glass, it has the advantages of high strength and high transmittance, which solves the technical problem that existing zero-expansion microcrystalline glass cannot achieve both high strength and high transmittance. It can meet the application requirements of high strength and high transmittance.

[0029] This invention provides a method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass. The process is simple to operate, easy to mass-produce, flexible, and efficient, and has broad prospects in actual industrial production. Attached Figure Description

[0030] Figure 1 This is a cross-sectional microstructure of the high-strength, high-transmittance, zero-expansion microcrystalline glass of Example 2. Detailed Implementation

[0031] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0032] Example 1 This embodiment provides a high-strength, high-transmittance, zero-expansion microcrystalline glass, which is prepared using the following method: (1) Weigh the corresponding weight of glass batch material according to the batching design. The alumina source is aluminum hydroxide and aluminum phosphate, the phosphorus pentoxide source is aluminum phosphate or aluminum metaphosphate, the sodium oxide source is sodium nitrate or sodium carbonate, the lithium oxide source is lithium carbonate, and the potassium oxide source is potassium nitrate or potassium carbonate. Specifically, in this embodiment, the following ingredients are weighed: 45.22 kg of quartz sand, 30.82 kg of aluminum hydroxide, 8.95 kg of aluminum phosphate, 1.92 kg of titanium dioxide, 1.78 kg of zirconium oxide, 0.95 kg of magnesium oxide, 1.12 kg of zinc oxide, 0.11 kg of sodium nitrate, 7.98 kg of lithium carbonate, 0.37 kg of potassium nitrate, 0.68 kg of clarifying agent (arsenic oxide, antimony oxide), and 0.1 kg of other ingredients (yttrium oxide). The glass batch material is mixed and passed through a 40-mesh nylon sieve. After sieving, it is further mixed and stirred until homogeneous. Then, the batch material is fed in batches of 5 kg at intervals of more than 2 hours. After feeding, it is placed in an air environment or under a vacuum of less than 10°C. - 3 In a Bar environment, the glass batch is heated to a melting temperature of 1650~1680 ℃, and after it becomes completely liquid, molten glass is obtained; (2) The molten glass is melted at high temperature. During the melting process, the atmosphere is controlled or vacuum melting is carried out and the glass is stirred thoroughly. Finally, the glass is clarified and then cooled down. After cooling down to a certain temperature, it is cast into shape or the casting is rapidly cooled and then melted again or the above process is repeated multiple times before casting. (3) After the homogeneous glass liquid is poured and cooled appropriately, it is poured. The diameter of the glass pouring pipe is ≥30mm. The pouring mold is made of platinum or cast iron. The inner wall of the mold is coated with a release agent and designed with air cooling or water cooling device. After the glass liquid is poured, the mold is cooled appropriately. After demolding, it is annealed to obtain the mother glass. Since glass has no fixed melting point, the operating parameters of the above steps can be selected within a preferred range by those skilled in the art, and all of them can satisfy the basic objective of the present invention to obtain the mother glass. (4) The mother glass obtained above is subjected to nucleation and crystallization treatment; the nucleation temperature in this embodiment is 650°C and the nucleation time is 20 h; the crystallization temperature is 760°C and the crystallization time is 10 h; after the mother glass completes nucleation and crystallization, it is cooled down to obtain a high-strength, high-transmittance, zero-expansion microcrystalline glass product.

[0033] Example 2 This embodiment provides a high-strength, high-transmittance, zero-expansion microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this embodiment lies in the different material design and nucleation and crystallization processes.

[0034] The raw material components weighed in this embodiment are as follows: 47.14 kg quartz sand, 28.21 kg aluminum hydroxide, 9.61 kg aluminum phosphate, 2.15 kg titanium dioxide, 1.58 kg zirconium oxide, 0.92 kg magnesium oxide, 1.05 kg zinc oxide, 0.01 kg sodium nitrate, 8.62 kg lithium carbonate, 0.23 kg potassium nitrate, 0.62 kg clarifying agent (arsenic oxide), and 0.1 kg other (yttrium oxide, lutetium oxide).

[0035] In this embodiment, the nucleation temperature is 655 °C and the nucleation time is 20 h; the crystallization temperature is 770 °C and the crystallization time is 12 h.

[0036] Example 3 This embodiment provides a high-strength, high-transmittance, zero-expansion microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this embodiment lies in the different material design and nucleation and crystallization processes.

[0037] The raw material components weighed in this embodiment are as follows: 49.77 kg quartz sand, 26.51 kg aluminum hydroxide, 9.09 kg aluminum phosphate, 1.92 kg titanium dioxide, 1.61 kg zirconium oxide, 0.94 kg magnesium oxide, 1.06 kg zinc oxide, 0 kg sodium nitrate, 7.98 kg lithium carbonate, 0.21 kg potassium nitrate, 0.81 kg clarifying agent (antimony oxide, ammonium nitrate), and 0.1 kg other (ytterbium oxide).

[0038] In this embodiment, the nucleation temperature is 660 °C and the nucleation time is 20 h; the crystallization temperature is 780 °C and the crystallization time is 14 h.

[0039] Example 4 This embodiment provides a high-strength, high-transmittance, zero-expansion microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this embodiment lies in the different material design and nucleation and crystallization processes.

[0040] The raw material components weighed in this embodiment are as follows: 51.12 kg quartz sand, 25.12 kg aluminum hydroxide, 9.46 kg aluminum phosphate, 1.93 kg titanium dioxide, 1.59 kg zirconium oxide, 0.97 kg magnesium oxide, 1.14 kg zinc oxide, 0 kg sodium nitrate, 7.64 kg lithium carbonate, 0.18 kg potassium nitrate, 0.75 kg clarifying agent (arsenic oxide, antimony oxide), and 0.1 kg other (yttrium oxide).

[0041] In this embodiment, the nucleation temperature is 665 °C and the nucleation time is 20 h; the crystallization temperature is 790 °C and the crystallization time is 16 h.

[0042] Example 5 This embodiment provides a high-strength, high-transmittance, zero-expansion microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this embodiment lies in the different material design and nucleation and crystallization processes.

[0043] The raw material components weighed in this embodiment are as follows: 52.03 kg quartz sand, 24.31 kg aluminum hydroxide, 9.14 kg aluminum phosphate, 1.89 kg titanium dioxide, 1.67 kg zirconium oxide, 0.93 kg magnesium oxide, 1.11 kg zinc oxide, 0 kg sodium nitrate, 7.89 kg lithium carbonate, 0.19 kg potassium nitrate, 0.74 kg clarifying agent (arsenic oxide, ammonium chloride), and 0.1 kg other (yttrium oxide).

[0044] In this embodiment, the nucleation temperature is 670 °C and the nucleation time is 20 h; the crystallization temperature is 800 °C and the crystallization time is 18 h.

[0045] Comparative Example 1 This comparative example provides a microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this comparative example lies in the different material design and nucleation and crystallization processes.

[0046] The raw material components weighed in this comparative example are as follows: 48.12 kg quartz sand, 33.01 kg aluminum hydroxide, 3.21 kg aluminum phosphate, 1.92 kg titanium oxide, 1.62 kg zirconium oxide, 0.95 kg magnesium oxide, 1.16 kg zinc oxide, 0.01 kg sodium nitrate, 8.87 kg lithium carbonate, 0.25 kg potassium nitrate, 0.78 kg clarifying agent (arsenic oxide), and 0.1 kg other (yttrium oxide).

[0047] The nucleation temperature of this comparative example was 660 ℃, and the nucleation time was 20 h; the crystallization temperature was 790 ℃, and the crystallization time was 20 h.

[0048] Comparative Example 2 This comparative example provides a microcrystalline glass, the preparation process of which is basically the same as that of Example 1. The difference in this comparative example lies in the different material design and nucleation and crystallization processes.

[0049] The raw material components weighed in this comparative example are as follows: 44.27 kg quartz sand, 22.14 kg aluminum hydroxide, 11.34 kg aluminum phosphate, 1.83 kg titanium dioxide, 1.45 kg zirconium oxide, 0.32 kg magnesium oxide, 1.01 kg zinc oxide, 5.5 kg sodium nitrate, 9.21 kg lithium carbonate, 2.12 kg potassium nitrate, 0.71 kg clarifying agent (arsenic oxide), and 0.1 kg other (yttrium oxide).

[0050] The nucleation temperature of this comparative example was 700 ℃, and the nucleation time was 20 h; the crystallization temperature was 820 ℃, and the crystallization time was 22 h.

[0051] Test Example 1 The ingredient lists for the above embodiments and comparative examples are shown in Table 1; correspondingly, the nucleation and crystallization treatment parameters are shown in Table 2.

[0052] Table 1: Ingredients (kg) for Examples and Comparative Examples

[0053] Table 2: Nucleation and Crystallization Processes of Examples and Comparative Samples

[0054] This test example characterizes the high-strength, high-transmittance, zero-expansion microcrystalline glass obtained in the examples and the microcrystalline glass of the comparative examples by testing the coefficient of thermal expansion (tested according to GB / T 16535-2008 Test Method for Linear Thermal Expansion Coefficient of Fine Ceramics - Top Rod Method), bending strength (tested according to GB / T 37781-2019 Test Method for Bending Strength of Glass Materials), internal transmittance (tested according to GB / T 2680-2021 and GB / T 7962.1-2010), density, etc. The performance of the samples of each example and comparative example is shown in Table 3 below.

[0055] Table 3: Performance of Examples and Comparative Samples

[0056] Based on the above test results and comparisons, it can be seen that, compared with Comparative Examples 1 and 2, in Examples 1 to 5, the content of each component and the corresponding melting and crystallization processes are all within the scope of the claims, and the coefficient of thermal expansion of the obtained glass is close to zero, all within (0±0.02)×10. -7 Within a certain temperature range, the coefficients of thermal expansion change with variations in the content of SiO2, Al2O3, and Li2O. The flexural strength is consistently greater than 225 MPa, and gradually increases with increasing silicon content. In the transmittance test, the glass sample thickness was 10 mm, and a 500 nm green visible light wavelength was selected as the incident wavelength. As seen in Examples 1 to 5, the transmittance of the microcrystalline glass changes accordingly with variations in the content of SiO2, Al2O3, and Li2O, but remains consistently greater than 90%. The glass prepared in Comparative Example 1 is outside the scope of this invention, resulting in abnormal crystal growth, devitrification, and a low negative coefficient of thermal expansion: -6.12 × 10⁻⁶. -7 / ℃. Although the flexural strength reaches its maximum value of 242.5 MPa, the density also reaches its highest value of 2.56 g / cm³. 3 .

[0057] Similarly, the glass prepared in Comparative Example 2 is not within the scope of this invention; its crystallization rate is insufficient, although its transmittance reaches 93.2%, close to that of transparent glass. However, its coefficient of thermal expansion reaches 1.38 × 10⁻⁶. -7 The temperature is relatively high, with a flexural strength of 158.1 MPa and a density of 2.41 g / cm³. 3 .

[0058] While considering the triple indicators of high strength, high transmittance, and zero expansion, Example 2 exhibits the lowest coefficient of expansion. The scanning electron microscope image of the cross-sectional morphology of the microcrystalline glass prepared using this method is shown below. Figure 1 As shown. Figure 1 The results show that the grain size distribution is uniform, with a grain size of about 30~40 nm, and all grains are close to spherical. The grains are densely arranged, and after hydrofluoric acid etching, there are no obvious pores on the surface, indicating that the glass has a high crystallization rate. This confirms that the present invention has the characteristics of high strength, high transmittance and zero expansion.

[0059] As can be seen from the above, by strictly limiting the composition, content, melting, crystallization, etc. of the glass system, a microcrystalline glass with the characteristics of high strength, high transmittance and near-zero expansion can be prepared by adopting the technical solution of the present invention. This fills the technical gap that the current zero-expansion microcrystalline glass cannot simultaneously achieve high strength, high transmittance and zero expansion. The product can meet the needs of high-end fields such as aerospace and lithography machines.

[0060] It is evident that the microcrystalline glass prepared by the method proposed in this invention, with its high strength, high transmittance, and near-zero expansion characteristics, represents a further improvement over existing technologies.

[0061] In the description of the invention, it should be noted that the terms "stirring," "mixing," "melting," and other process descriptions are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the process referred to must have a specific structure and operation. Therefore, they should not be construed as limitations on the invention.

[0062] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A high-strength, high-transmittance, zero-expansion microcrystalline glass, characterized in that, The microcrystalline glass is composed of lithium aluminum silicate and contains crystals and residual glass phases. The raw material components, by weight percentage and in terms of oxides, contain: 50%~70% SiO2, 25%~40% Al2O3, 2%~10% Li2O, 1%~10% P2O5, 0.5%~5% MgO, 0.5%~5% ZnO, 0~5% K2O, 0~5% Na2O, 0.5%~5% TiO2, 0.5%~5% ZrO2, 0.5%~2% clarifying agent, and 0~2% other components; the other components include one or more of Y2O3, Yb2O3, and Lu2O3; the sum of the mass percentages of all raw material components is 100%.

2. The high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 1, characterized in that: In the high-strength, high-transmittance, zero-expansion microcrystalline glass, the molar percentage of oxides is SiO2:Al2O3 = 2.5~4.5; Al2O3:Li2O = 1.2~4.

2.

3. The high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 1, characterized in that: In the high-strength, high-transmittance, zero-expansion microcrystalline glass, the molar percentage of oxides is ZrO2:(ZrO2+TiO2)=0.2~0.

5.

4. The high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 1, characterized in that: In the high-strength, high-transmittance, zero-expansion microcrystalline glass, the clarifying agent includes one or more of As2O3, Sb2O3, NH4Cl, and NH4NO3.

5. A method for preparing a high-strength, high-transmittance, zero-expansion microcrystalline glass as described in any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Based on the design ratio of high-strength, high-transmittance, zero-expansion microcrystalline glass, prepare raw material components to obtain glass batch; heat the glass batch to melt to form molten glass liquid; (2) The molten glass is stirred and clarified to obtain a homogeneous glass melt; (3) The homogeneous molten glass is poured into a mold of the target shape and annealed to obtain the mother glass; (4) The mother glass is subjected to nucleation and crystallization treatment to obtain high-strength, high-transmittance, zero-expansion microcrystalline glass.

6. The method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 5, characterized in that: In step (1), the purity of the glass batch is ≥99.95%; the melting temperature of the glass batch is 1650~1680 ℃.

7. The method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 5, characterized in that: In step (2), the stirring temperature is 1650~1680 ℃ and the time is 20~60 h; the clarification temperature is 1650~1680 ℃ and the time is 20~60 h.

8. The method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 5, characterized in that: In step (3), the temperature of the homogeneous glass liquid pouring is 1500~1600 ℃; the mold preheating temperature is 300~1000 ℃.

9. The method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 5, characterized in that: In step (3), the annealing cooling rate is ≤1.5 ℃ / h.

10. The method for preparing high-strength, high-transmittance, zero-expansion microcrystalline glass according to claim 5, characterized in that: In step (4), the nucleation temperature is 620~700 ℃ and the nucleation time is 10~50 h; the crystallization temperature is 720~820 ℃ and the crystallization time is 10~50 h.

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