Thermal shock resistant transparent high borosilicate glass

Abstract

The invention belongs to the technical field of glass materials, and discloses thermal shock resistant transparent high borosilicate glass which comprises the following components in percentage by weight: 60-70% of silicon dioxide, 18-22% of diboron trioxide, 4-7% of aluminum oxide, 3-5% of magnesium oxide, 2-4% of alkali metal oxide, 0.5-1.5% of nano silicon nitride and 0.5-1% of nano aluminum titanate. The thermal shock temperature difference of the glass within the temperature change range of 20-200 DEG C is larger than or equal to 180 DEG C, the light transmittance within the visible light range of 400-760 nm is larger than or equal to 85%, the alkali metal oxide is composed of sodium oxide and potassium oxide, the weight ratio of the sodium oxide to the potassium oxide is 1: 1-3: 1, the average particle size of the nanometer silicon nitride is smaller than or equal to 100 nm, and the nanometer silicon nitride is evenly dispersed in the glass matrix; according to the thermal-shock-resistant transparent high borosilicate glass and the preparation method thereof, the thermal shock resistance and light transmittance of the glass are improved by optimizing the chemical components of the glass and adding the special nanoparticles in cooperation with a specific preparation process, and the thermal shock resistance of the glass is improved. The problems that existing high borosilicate glass is insufficient in thermal shock resistance and low in light transmittance in a high-temperature environment are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of glass materials, in particular to a thermal shock resistant transparent high borosilicate glass. Background Art

[0002] Borosilicate glass is widely used in numerous fields due to its excellent chemical stability, thermal stability, and optical properties. However, in some specialized applications, such as high-temperature observation windows in aerospace and high-temperature monitoring equipment in the metallurgical industry, the thermal shock and optical properties of conventional borosilicate glass still fall short of expectations. When glass is subjected to rapid temperature fluctuations, thermal stresses are generated within it. If these stresses exceed the glass's strength limit, the glass will fracture. Improving the thermal shock resistance of glass, enabling it to withstand large temperature fluctuations without breaking, has become a key research area. Prior art methods for improving the thermal shock resistance of glass primarily involve optimizing its chemical composition and adding reinforcing phases. For example, the thermal expansion coefficient of glass can be altered by adjusting the ratios of key components such as silicon dioxide and boron trioxide; or reinforcing phases such as ceramic particles and whiskers can be added to the glass to improve its mechanical properties. However, these methods have limitations. For example, the added reinforcing phases tend to agglomerate, resulting in an uneven internal structure and affecting the glass's light transmittance and mechanical properties. Furthermore, the effectiveness of optimizing the chemical composition is limited, making it difficult to meet the thermal shock resistance requirements of glass under extreme environments. Therefore, a new high-borosilicate glass with excellent thermal shock resistance and high light transmittance, as well as a preparation method thereof, was proposed to address these issues. Summary of the Invention

[0003] The purpose of the present invention is to provide a thermal shock-resistant transparent high-borosilicate glass and a preparation method thereof. By optimizing the chemical composition of the glass and adding special nanoparticles, and combining with a specific preparation process, the thermal shock resistance and light transmittance of the glass are improved, thereby solving the problems of insufficient thermal shock resistance and low light transmittance of existing high-borosilicate glass in high-temperature environments.

[0004] In order to achieve the above object, the present invention provides the following technical solutions: The technical solution provided by the present invention is: a thermal shock-resistant transparent high-borosilicate glass, which comprises the following components by weight percentage: 60-70% silicon dioxide, 18-22% boron trioxide, 4-7% aluminum oxide, 3-5% magnesium oxide, 2-4% alkali metal oxide, 0.5-1.5% nano-silicon nitride, and 0.5-1% nano-aluminum titanate; the glass has a thermal shock temperature difference of 180°C or greater within a temperature range of 20°C to 200°C, and a light transmittance of 85% or greater within a visible light range of 400-760nm; the alkali metal oxide is composed of sodium oxide and potassium oxide in a weight ratio of 1:1-3:1; the nano-silicon nitride has an average particle size of 100nm or less and is uniformly dispersed in the glass matrix.

[0005] Furthermore, the thermal shock-resistant transparent high-borosilicate glass also includes nano-silicon carbide particles accounting for 0.1-1% of the total amount, the average particle size of the nano-silicon carbide particles is ≤50nm, and the surface is chemically bonded to the glass matrix after hydroxylation treatment, and the hydroxylation treatment includes the following steps: adding the nano-silicon carbide particles to an ethanol-deionized water solution with a volume ratio of 1:1, ultrasonically dispersing for 30-60 minutes to form a suspension with a concentration of 5-10g / L; adding γ-aminopropyltriethoxysilane coupling agent accounting for 1-3% of the weight of the particles to the suspension, stirring and reacting at 60-80°C for 2-4 hours; after the reaction is completed, centrifugation is performed, washing with deionized water 3 times, and drying at 80-100°C for 12-24 hours to obtain surface hydroxylated nano-silicon carbide particles. During the stirring reaction, the pH value of the system is adjusted to 8-9 by 0.1M sodium hydroxide solution to ensure that the silane coupling agent is hydrolyzed to generate silanol groups and form covalent bonds with the hydroxyl groups on the surface of the nano-silicon carbide.

[0006] In addition, the thermal expansion coefficient of the glass (20-300°C) is (2.8-3.4)×10 -6 / ℃, the microstructure contains a cordierite microcrystalline phase with a particle size of 5-15μm, the cordierite microcrystalline phase accounts for 3%-8% of the total volume of the glass, the microcrystalline phase is induced to form by annealing at 550-650℃, and the glass may also include erbium oxide accounting for 0.05-0.3% of the total amount, and the erbium oxide is uniformly distributed in the glass matrix.

[0007] The present invention also provides a method for preparing the above-mentioned thermal shock resistant transparent high borosilicate glass, comprising the following steps: S1: Weigh silicon dioxide, boron trioxide, aluminum oxide, magnesium oxide, alkali metal oxide, and nano-silicon nitride according to weight percentage; optionally weigh nano-silicon carbide or erbium oxide; S2: After mixing the raw materials weighed in S1, grind them in a ball mill at a speed of 80-120 rpm for 30-60 minutes to obtain a uniform mixed powder; during the mixing and grinding process, add 0.1-0.5% of anhydrous ethanol as a dispersant based on the total weight of the raw materials to prevent the nanoparticles from agglomerating; S3: The mixed powder is placed in a platinum crucible and melted at 1500-1600°C for 2-4 hours. During the melting process, ultrasonic vibration with a frequency of 20-40kHz and a power of 500-1000W is applied, and the vibration time accounts for 30%-50% of the total melting time. The ultrasonic vibration is applied by an immersed ultrasonic transducer, and the transducer probe is inserted into the glass liquid to a depth of 1 / 3-1 / 2 of the crucible height to ensure that the dispersion uniformity of the nanoparticles is ≥95%; S4: heating the molten glass to 1450-1550°C and maintaining it for 1-2 hours for clarification, then cooling it to 1400-1500°C and maintaining it for 1-2 hours for homogenization; S5: Pour the homogenized glass liquid into a mold and cool it to room temperature at a cooling rate of 5-15°C / min to obtain a primary glass product; S6: Place the primary glass product in an annealing furnace, heat it to 550-650°C at a rate of 10-20°C / min, hold it for 3-6 hours, and cool it to room temperature to induce the formation of a cordierite microcrystalline phase. By controlling the heating rate (5-10°C / min) and holding time (2-4 hours), the particle size of the cordierite microcrystalline phase is controlled to be 5-15μm, and the crystal phase accounts for 3%-8%; S7: If the glass needs to form a surface composite coating, use plasma enhanced chemical vapor deposition to deposit a 20-50 nm thick silicon nitride-silicon carbide composite coating on the glass surface. The deposition parameters are: silane to ammonia flow ratio of 1:3-1:5, RF power of 100-300W, deposition temperature of 300-400°C, and processing time of 20-40 minutes.

[0008] The beneficial effects of this technical solution are: (1) The present invention effectively reduces the thermal expansion coefficient of glass and improves the toughness and strength of glass by rationally designing the chemical composition of glass and adding nano-silicon nitride and nano-silicon carbide particles. Nano-silicon nitride is evenly dispersed in the glass matrix, which can form a uniform stress distribution inside the glass and relieve thermal stress. Nano-silicon carbide particles form chemical bonds with the glass matrix after surface hydroxylation treatment, which strengthens the bonding force between the particles and the matrix and further improves the thermal shock resistance of the glass. The thermal shock temperature difference of the glass in the temperature range of 20°C to 200°C is ≥180°C, and the glass can withstand large temperature changes without breaking.

[0009] (2) Strictly control the particle size and dispersibility of the raw materials, and use ultrasonic vibration-assisted melting process to ensure the uniform dispersion of nanoparticles, avoiding the influence of particle agglomeration on the transmittance of the glass. At the same time, optimize the chemical composition and preparation process of the glass, reduce the bubbles and impurities inside the glass, and make the transmittance of the glass in the visible light range of 400-760nm ≥85%, meeting the requirements of the optical field for the light transmittance of glass.

[0010] (3) The cordierite microcrystalline phase formed in the glass microstructure improves the hardness and wear resistance of the glass; the preparation of the surface composite coating further enhances the surface hardness and chemical stability of the glass, giving the glass good comprehensive mechanical properties.

[0011] (4) The preparation method provided by the present invention can stably prepare thermal shock-resistant transparent high-borosilicate glass with excellent performance by precisely controlling various process parameters, such as raw material ratio, grinding time, melting temperature, ultrasonic vibration parameters, annealing temperature and time, etc. The process has good process repeatability and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a parameter table of Example 1 of a thermal shock resistant transparent high borosilicate glass proposed by the present invention; Figure 2 This is a parameter table of Example 2 of a thermal shock resistant transparent high borosilicate glass proposed by the present invention; Figure 3 This is a parameter table of Example 3 of a thermal shock resistant transparent high borosilicate glass proposed by the present invention; Figure 4 The following is a table comparing the parameters of various embodiments of the thermal shock resistant transparent high borosilicate glass proposed in the present invention. DETAILED DESCRIPTION

[0013] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] The specific implementation process is as follows: Example 1: See also Figure 1 and Figure 4 The present invention provides a technical solution: a thermal shock resistant transparent high borosilicate glass, comprising the following steps: S1: Weigh by weight 64.5% silicon dioxide, 22% boron trioxide, 5% aluminum oxide, 3% magnesium oxide, 4% alkali metal oxide (3% sodium oxide, 1% potassium oxide), 1% nano-silicon nitride, and 0.5% nano-aluminum titanate; S2: After mixing the weighed raw materials, grind them in a ball mill at 100 rpm for 45 minutes, and add 0.3% of anhydrous ethanol as a dispersant based on the total weight of the raw materials to obtain a uniform mixed powder; S3: The mixed powder is placed in a platinum crucible and melted at 1550°C for 3 hours. During the melting process, ultrasonic vibration with a frequency of 30 kHz and a power of 750 W is applied. The vibration time accounts for 40% of the total melting time. The ultrasonic vibration is applied by an immersed ultrasonic transducer. The transducer probe is inserted into the glass liquid to a depth of 1 / 2 of the crucible height to obtain the molten glass liquid. S4: heating the molten glass to 1500°C and maintaining it for 1.5 hours for clarification, then cooling it to 1450°C and maintaining it for 1.5 hours for homogenization; S5: Pour the homogenized glass liquid into a mold and cool it to room temperature at a cooling rate of 10°C / min to obtain a primary glass product; S6: Place the glass sample into an annealing furnace, raise the temperature to 600°C at a rate of 15°C / min, keep the temperature for 4 hours, and cool it to room temperature in the furnace to induce the formation of a cordierite microcrystalline phase; 3. According to the test, the thermal shock temperature difference of the glass in the temperature range of 20℃ to 200℃ is 185℃, the light transmittance in the visible light range of 400-760nm is 88%, and the thermal expansion coefficient (20-300℃) is 3.0×10 -6 / °C, the cordierite microcrystals in the microstructure range in size from 8 to 12μm, accounting for 5% of the total crystalline phase. These data demonstrate that this combination of raw material ratios and process parameters results in glass with excellent thermal shock resistance, high transmittance, and a reasonable thermal expansion coefficient. Furthermore, the successful induction of the formation of cordierite microcrystals of a specific proportion and size improves the overall performance of the glass. Compared to conventional high-borosilicate glass without the addition of nano-silicon nitride and special processing, the glass exhibits significantly improved thermal shock resistance and mechanical properties, while its transmittance meets basic optical requirements.

[0015] Example 2: See also Figure 2 and Figure 4 The present invention provides a technical solution: a thermal shock resistant transparent high borosilicate glass, comprising the following steps: S1: Weigh by weight 61% silicon dioxide, 22% boron trioxide, 6% aluminum oxide, 4% magnesium oxide, 4% alkali metal oxide (2% sodium oxide, 2% potassium oxide), 1.5% nano-silicon nitride, 0.8% nano-aluminum titanate, and 0.7% nano-silicon carbide particles; The surface hydroxylation treatment of nano-silicon carbide particles is as follows: the nano-silicon carbide particles are added to an ethanol-deionized water solution with a volume ratio of 1:1, and ultrasonically dispersed for 45 minutes to form a suspension with a concentration of 8 g / L; γ-aminopropyltriethoxysilane coupling agent is added to the suspension at a concentration of 2% by weight of the particles, and the suspension is stirred and reacted at 70°C for 3 hours. During the reaction, the pH value of the system is adjusted to 8.5 with a 0.1M sodium hydroxide solution; after the reaction, the solution is centrifuged, washed three times with deionized water, and dried at 90°C for 18 hours to obtain surface hydroxylated nano-silicon carbide particles; S2: After mixing the weighed raw materials, grind them in a ball mill at 110 rpm for 50 minutes, and add 0.4% of anhydrous ethanol as a dispersant based on the total weight of the raw materials to obtain a uniform mixed powder; S3: The mixed powder is placed in a platinum crucible and melted at 1580°C for 3.5 hours. During the melting process, ultrasonic vibration with a frequency of 35kHz and a power of 800W is applied. The vibration time accounts for 45% of the total melting time. The ultrasonic vibration is applied by an immersed ultrasonic transducer. The transducer probe is inserted into the glass liquid to a depth of 1 / 2 of the crucible height to obtain molten glass liquid. S4: heating the molten glass to 1520°C and holding it for 1.8 hours for clarification, then cooling it to 1480°C and holding it for 1.8 hours for homogenization; S5: Pour the homogenized glass liquid into a mold and cool it to room temperature at a cooling rate of 12°C / min to obtain a primary glass product; S6: Place the glass sample into an annealing furnace, raise the temperature to 620°C at a rate of 18°C / min, hold the temperature for 5 hours, and cool the glass sample to room temperature to induce the formation of a cordierite microcrystalline phase. After testing, the thermal shock temperature difference of the glass in the temperature range of 20℃ to 200℃ is increased to 190℃, the transmittance in the visible light range of 400-760nm is 86%, and the thermal expansion coefficient (20-300℃) is 2.9×10 -6 / °C, the cordierite microcrystalline phase in the microstructure has a particle size of 7-13μm, accounting for 6% of the crystalline phase. The addition of nano-silicon carbide and special treatment further improve the glass's thermal shock resistance, increasing the thermal shock temperature difference by 5°C. The thermal expansion coefficient is reduced, making the glass more stable during temperature fluctuations. The increased proportion of the microcrystalline phase enhances the glass's hardness and wear resistance. Although light transmittance has decreased slightly, it still meets the requirement of ≥85%. This demonstrates that the raw material and process adjustments have improved key performance while having minimal impact on light transmittance, resulting in significant overall performance optimization.

[0016] Embodiment three: See also Figure 3 and Figure 4 The present invention provides a technical solution: a thermal shock resistant transparent high borosilicate glass, comprising the following steps: S1: Weigh, by weight, 70% silicon dioxide, 18% boron trioxide, 4% aluminum oxide, 3.5% magnesium oxide, 2% alkali metal oxide (1.5% sodium oxide, 0.5% potassium oxide), 0.5% nano-silicon nitride, 1% nano-aluminum titanate, 0.8% nano-silicon carbide particles, and 0.2% erbium oxide; the surface hydroxylation treatment of the nano-silicon carbide particles is the same as in Example 2; S2: After mixing the weighed raw materials, grind them in a ball mill at 90 rpm for 55 minutes, and add 0.2% of anhydrous ethanol as a dispersant based on the total weight of the raw materials to obtain a uniform mixed powder; S3: The mixed powder is placed in a platinum crucible and melted at 1520°C for 2.5 hours. During the melting process, ultrasonic vibration with a frequency of 25kHz and a power of 600W is applied. The vibration time accounts for 35% of the total melting time. The ultrasonic vibration is applied by an immersed ultrasonic transducer. The transducer probe is inserted into the glass liquid to a depth of 1 / 3 of the crucible height to obtain molten glass liquid. S4: heating the molten glass to 1480°C and holding it for 1.2 hours for clarification, then cooling it to 1420°C and holding it for 1.2 hours for homogenization; S5: Pour the homogenized glass liquid into a mold and cool it to room temperature at a cooling rate of 8°C / min to obtain a primary glass product; S6: Place the glass sample into an annealing furnace, raise the temperature to 580°C at a rate of 12°C / min, hold the temperature for 3.5 hours, and cool the glass sample to room temperature to induce the formation of a cordierite microcrystalline phase. S7: A 30 nm thick silicon nitride-silicon carbide composite coating was deposited on the glass surface using plasma-enhanced chemical vapor deposition (PECVD). The deposition parameters were: 1:4 silane to ammonia flow ratio, 200 W RF power, 350°C deposition temperature, and 30 min treatment time. After testing, the thermal shock temperature difference of the glass in the temperature range of 20℃ to 200℃ was further increased to 195℃, the transmittance in the visible light range of 400-760nm was 87%, and the thermal expansion coefficient (20-300℃) was 3.1×10 -6 / °C, the particle size of the cordierite microcrystal phase in the microstructure ranges from 6 to 14μm, accounting for 7% of the total crystalline phase. The composite surface coating improves the surface hardness and chemical stability of the glass. The addition of erbium oxide and a larger number of nano-silicon carbide particles synergistically enhances the glass's thermal shock resistance. The preparation of the surface coating imparts enhanced surface properties to the glass, significantly improving its suitability in complex environments such as high temperatures and corrosion without compromising light transmittance. Compared to the previous two examples, the overall performance is further enhanced, fully demonstrating the significant performance improvement achieved through raw material and process optimization in this technical solution.

[0017] See also Figure 1-4 : In Examples 1-3, the thermal shock temperature differences of the glass within the temperature range of 20°C to 200°C reached 185°C, 190°C, and 195°C, respectively. Compared with traditional borosilicate glass, this technical solution significantly improves the thermal shock resistance of the glass by adding nano-silicon nitride, surface treating nano-silicon carbide, and optimizing the preparation process. In Example 3, the thermal shock temperature difference reaches the highest value due to the further addition of erbium oxide and the preparation of a surface composite coating. This demonstrates that the synergistic effect of various components and processes can effectively enhance the glass's ability to resist thermal stress, making the glass more stable in high-temperature environments, far exceeding the state of the art. In the visible light range of 400-760nm, the transmittances of Examples 1-3 were 88%, 86%, and 87%, respectively, all meeting the standard of ≥85%. This is due to the precise control of the raw material particle size and dispersion, combined with the ultrasonic vibration-assisted melting process, which avoids the impact of nanoparticle agglomeration on transmittance. At the same time, the optimized preparation process reduces bubbles and impurities in the glass. Compared with the existing technology that adds a reinforcing phase to reduce transmittance, this technical solution effectively ensures the light transmission performance of the glass while improving other properties, meeting the application requirements in the optical field. The thermal expansion coefficients (20-300°C) of Examples 1-3 are 3.0×10 -6 / ℃、2.9×10 -6 / ℃ and 3.1×10 -6 / ℃, at (2.8-3.4)×10 -6 By optimizing the chemical composition, especially the ratio of alkali metal oxides, and adding nanoparticles, the thermal expansion coefficient of the glass is effectively reduced, reducing the thermal stress generated by the glass during temperature changes. This precise control is difficult to achieve with traditional glass, greatly improving the applicability of the glass in different temperature environments. In each embodiment, through a specific annealing treatment, a cordierite microcrystalline phase with a particle size of 5-15 μm and a crystal phase proportion of 3%-8% was successfully induced in the glass microstructure; the particle size and crystal phase proportion of the cordierite microcrystalline phase in Examples 1-3 were in line with expectations, and the formation of this microcrystalline phase significantly improved the hardness and wear resistance of the glass; compared with traditional glass that has not formed a specific microcrystalline phase, this technical solution further enhances the mechanical properties of the glass by controlling the annealing process parameters and precisely regulating the formation of the microcrystalline phase, which is an important innovation that distinguishes this technical solution from the prior art.

[0018] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A thermal shock resistant transparent borosilicate glass, characterized in that: Calculated by weight percentage, it includes the following ingredients: 60-70% silicon dioxide, 18-22% boron trioxide, 4-7% aluminum oxide, 3-5% magnesium oxide, 2-4% alkali metal oxide, 0.5-1.5% nano silicon nitride, and 0.5-1% nano aluminum titanate; The thermal shock temperature difference of the glass within the temperature range of 20°C to 200°C is ≥180°C, and the light transmittance within the visible light range of 400-760nm is ≥85%; The alkali metal oxide is composed of sodium oxide and potassium oxide, and the weight ratio of the two is 1:1 to 3:1; The average particle size of the nano silicon nitride is less than or equal to 100 nm, and the nano silicon nitride is uniformly dispersed in the glass matrix.

2. The thermal shock resistant transparent high borosilicate glass according to claim 1, characterized in that: The invention also includes nano-silicon carbide particles accounting for 0.1-1% of the total amount, wherein the average particle size of the nano-silicon carbide particles is ≤50nm, and the surface of the nano-silicon carbide particles is chemically bonded to the glass matrix after being hydroxylated; The hydroxylation treatment comprises the following steps: Add nano-silicon carbide particles to an ethanol-deionized water solution with a volume ratio of 1:1 and ultrasonically disperse for 30-60 minutes to form a suspension with a concentration of 5-10 g / L; Add γ-aminopropyltriethoxysilane coupling agent accounting for 1-3% of the particle weight to the suspension, and stir and react at 60-80°C for 2-4 hours; After the reaction is completed, the mixture is centrifuged, washed with deionized water for three times, and dried at 80-100° C. for 12-24 hours to obtain surface hydroxylated nano-silicon carbide particles.

3. The thermal shock resistant transparent high borosilicate glass according to claim 2, characterized in that: During the stirring reaction, the pH value of the system is adjusted to 8-9 by using 0.1M sodium hydroxide solution to ensure that the silane coupling agent is hydrolyzed to generate silanol groups and form covalent bonds with the hydroxyl groups on the surface of the nano-silicon carbide.

4. The thermal shock resistant transparent high borosilicate glass according to claim 1, characterized in that: The thermal expansion coefficient of the glass (20-300°C) is (2.8-3.4)×10 -6 / ℃, the microstructure contains a cordierite microcrystalline phase with a particle size of 5-15μm, the cordierite microcrystalline phase accounts for 3%-8% of the total volume of the glass, and the microcrystalline phase is induced by annealing treatment at 550-650℃.

5. The thermal shock resistant transparent high borosilicate glass according to claim 1, characterized in that: The glass matrix further comprises 0.05-0.3% of erbium oxide, which is uniformly distributed in the glass matrix.

6. A method for preparing the thermal shock resistant transparent high borosilicate glass according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Weigh each component according to weight percentage; S2: After mixing the ingredients weighed in S1, grind them in a ball mill at 80-120 rpm for 30-60 minutes to obtain a uniform mixed powder; S3: Place the mixed powder into a platinum crucible and melt it at 1500-1600°C for 2-4 hours. Apply ultrasonic vibration with a frequency of 20-40kHz and a power of 500-1000W during the melting process. The vibration time accounts for 30%-50% of the total melting time. S4: heating the molten glass to 1450-1550°C and maintaining it for 1-2 hours for clarification, then cooling it to 1400-1500°C and maintaining it for 1-2 hours for homogenization; S5: Pour the homogenized glass liquid into a mold and cool it to room temperature at a cooling rate of 5-15°C / min to obtain a primary glass product; S6: placing the glass product into an annealing furnace, heating it to 550-650°C at a rate of 10-20°C / min, keeping it at that temperature for 3-6 hours, and cooling it to room temperature in the furnace to induce the formation of a cordierite microcrystalline phase; S7: If the glass described in claim 1 needs to form a surface composite coating, a plasma-enhanced chemical vapor deposition method is used to deposit a silicon nitride-silicon carbide composite coating with a thickness of 20-50 nm on the glass surface. The deposition parameters are: silane to ammonia flow ratio of 1:3-1:5, RF power of 100-300 W, deposition temperature of 300-400 ° C, and treatment time of 20-40 minutes.

7. The preparation method according to claim 6, characterized in that S3 ultrasonic vibration is applied through an immersed ultrasonic transducer, and the transducer probe is inserted into the glass liquid to a depth of 1 / 3-1 / 2 of the crucible height to ensure that the dispersion uniformity of the nanoparticles is ≥95%.

8. The preparation method according to claim 6, characterized in that During the S6 annealing treatment, by controlling the heating rate (5-10°C / min) and the holding time (2-4 hours), the particle size of the cordierite microcrystalline phase is controlled at 5-15μm, and the crystal phase accounts for 3%-8%.

9. The preparation method according to claim 6, characterized in that During the S2 mixing and grinding process, 0.1-0.5% of anhydrous ethanol by weight of the total raw materials is added as a dispersant to prevent the nanoparticles from agglomerating.

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