Aluminum-doped opaque quartz glass and manufacturing method thereof

Abstract

The invention discloses aluminum-doped opaque quartz glass and a manufacturing method thereof. The manufacturing method comprises the following steps: S1, selecting high-purity quartz sand as a base material; s2, adding an aluminum-containing compound and a pore-forming agent into the high-purity quartz sand selected in the step S1, and fully and uniformly mixing to obtain a mixture; s3, putting the mixture mixed in the step S2 into a mold for shaping; s4, calcining the shaped mixture by adopting oxyhydrogen flame; and S5, naturally cooling after calcining is completed, and demolding to obtain the milky-white opaque quartz glass, so that the milky-white opaque quartz glass has high whiteness and low thermal conductivity, and has high-temperature deformation resistance superior to that of traditional milky-white quartz glass.

Description

Technical Field

[0001] This invention relates to the field of quartz materials technology, and in particular to a high-temperature service-oriented aluminum-doped opaque quartz glass and its manufacturing method. Background Technology

[0002] Milky white opaque quartz is widely used as a component in thermal process equipment in semiconductor wafer manufacturing, as well as in industrial lighting fixture covers and high-temperature kiln linings due to its excellent thermal stability, thermal shock resistance, low thermal conductivity and good infrared radiation characteristics.

[0003] Traditional opaque, milky-white quartz glass typically achieves its effect by introducing trace amounts of pore-forming agents (such as silicon carbide, silicon nitride, carbon powder, graphite powder, boron nitride, etc.) into high-purity quartz sand, which then melts at high temperatures to form numerous tiny bubbles. However, this material exhibits significant drawbacks under high-temperature (especially above 1200°C) and prolonged heating conditions: First, it has weak resistance to crystallization. The silicon and oxygen atoms in the glass network structure easily transform from a disordered amorphous state to an ordered cristobalite crystal. This crystallization phenomenon directly alters the thermal expansion coefficient of the surface quartz glass and easily leads to cracking or even peeling, ultimately causing device failure. Second, it has weak resistance to high-temperature deformation. Under its own weight or external load, quartz glass at high temperatures will undergo viscous flow, resulting in softening and deformation, leading to a significant decrease in the material's dimensional stability. These defects severely limit the application of traditional opaque, milky-white quartz glass in higher-temperature environments and in scenarios with higher lifespan requirements.

[0004] Existing technologies for optimizing the performance of quartz glass have significant limitations: Some technologies (such as CN1413175A) dope SiO2 particles with 5-20 ppm aluminum (in nano-scale Al2O3 form), but their core purpose is only to "increase viscosity". Moreover, the aluminum doping amount is too low to effectively suppress crystal nucleation growth at high temperatures, and it does not mention the consideration of "opaqueness". Other technologies (such as CN106430952B and CN106380072B) aim at "resistance to hydrofluoric acid corrosion" and increase the Al2O3 doping amount to 0.5-10% (i.e. 5000-100000 ppm). However, the high concentration of aluminum will destroy the uniformity of the bubbles formed by the pore-forming agent, resulting in a decrease in opacity, and it does not involve optimization for resistance to high-temperature crystallization and deformation. Conventional optimization methods in the industry (such as adjusting the type of pore-forming agent and optimizing the melting process) can only make minor adjustments to a single performance dimension and cannot achieve a synergistic improvement in "opaqueness, anti-crystallization, and resistance to high-temperature deformation." Therefore, developing a new type of opaque quartz material that combines the physical and chemical properties of conventional milky white opaque quartz glass with significantly enhanced resistance to crystallization and deformation has become an urgent technical challenge. Summary of the Invention

[0005] To address the issues of traditional opaque quartz glass being prone to crystallization and deformation at high temperatures, and the difficulty of balancing optical and mechanical properties with existing technologies, this invention proposes an aluminum-doped opaque quartz glass and its manufacturing method. The core innovation lies in achieving a synergistic effect of four properties—high whiteness (≥ 90%), low thermal conductivity, resistance to high-temperature crystallization, and resistance to high-temperature deformation—through specific concentrations of aluminum doping and precise process control.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: aluminum-doped opaque quartz glass, including milky white opaque quartz glass, wherein the bubble pore size in the milky white opaque quartz glass is in the range of 5-150 μm.

[0007] Preferably, when the thickness of the milky white opaque quartz glass is 10 mm, the whiteness is 70-90%.

[0008] Another topic is a method for manufacturing aluminum-doped opaque quartz glass, comprising the following steps: S1. High-purity quartz sand is selected as the matrix material; S2. Add aluminum-containing compounds and pore-forming agents to the high-purity quartz sand selected in step S1, and mix thoroughly to obtain a mixture. S3. Place the mixture from step S2 into a mold for shaping; S4. The calcined mixture is then subjected to an oxyhydrogen flame. S5. After calcination, allow the glass to cool naturally. Once cooled, demold to obtain milky white, opaque quartz glass.

[0009] Preferred options also include: S6. According to the product drawing requirements, the opaque quartz glass obtained in step S5 is machined to obtain the opaque quartz glass product. S7. Clean the milky white, opaque quartz glass product and allow it to air dry naturally. S8. Annealing and stress-relieving treatment is performed on the dried milky white opaque quartz glass product.

[0010] Preferably, in step S2, the purity of the aluminum compound is ≥ 99.99%, and the doping amount is 50-150 ppm; the purity of the pore-forming agent is ≥ 99.9%, the particle size is 500-800 mesh, and the doping amount is 0.1-5.0 wt%.

[0011] Preferably, the aluminum-containing compound is one or more of aluminum hydroxide, aluminum nitrate, or aluminum oxide; and the pore-forming agent is one or more of silicon carbide, silicon nitride, and boron nitride.

[0012] Preferably, the sintering time in step S4 is in the range of 30-60 min.

[0013] Preferably, the cleaning operation in step S7 is as follows: the qualified milky white opaque quartz glass product is placed in a hydrofluoric acid solution with a volume fraction of 5-10% and soaked for 10-30 minutes, and then rinsed repeatedly with pure water several times.

[0014] Preferably, the machining process in step S6 is a cold or hot processing process, including polishing, cutting, and sandblasting.

[0015] Preferably, the annealing temperature in step S8 is 1000~1100℃, and the holding time is 4~8 h.

[0016] Compared with the prior art, the advantage of this invention is that the anti-crystallization performance is significantly improved: aluminum element (Al 3+ It can replace some of the silicon element (Si) in the quartz glass network. 4+ This inhibits the formation and growth of cristobalite crystal nuclei. Samples were prepared and tested according to the standard GB / T 42800-2023. After being kept at 1200℃ for 24 hours, the thickness of the crystallized layer was less than 50 μm, which is significantly lower than that of traditional milky white opaque quartz products (60-80 μm).

[0017] Increased high-temperature resistance to deformation: The introduction of aluminum effectively increases the high-temperature viscosity of quartz glass. According to the GB / T42800-2023 standard, after sample preparation and testing, the deformation rate is <1% after holding at 1200℃ for 24 hours, which is lower than that of traditional opaque quartz glass (2.0-3.0%).

[0018] While maintaining high whiteness and low thermal conductivity, opaque milky white quartz glass exhibits superior resistance to high-temperature deformation compared to traditional milky white quartz glass. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic flowchart of the aluminum-doped opaque quartz glass preparation process of the present invention; Figure 2 This is a schematic diagram of the bubble distribution of the product of the present invention using an optical microscope; Figure 3A comparison diagram of the crystallization layer thickness of the conventional product and the product of this invention after being kept at 1200℃ for 24 hours; Figure 4 This is a comparison chart of the deformation rates of traditional products and the product of this invention after being kept at 1200℃ for 24 hours. Detailed Implementation

[0021] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that these descriptions are merely descriptive and exemplary and should not be construed as limiting the scope of the invention.

[0022] It should be noted that similar labels in the following figures indicate similar items; therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0023] refer to Figures 1-4 This invention provides a method for preparing aluminum-doped opaque quartz glass, the specific implementation of which is as follows: Example 1

[0024] A method for manufacturing aluminum-doped opaque quartz glass, comprising the following steps: S1. Select 80-200 mesh high-purity quartz sand (purity ≥ 99.99%) as the matrix material, feed the raw material into a screening machine for repeated screening, and obtain 100-140 mesh quartz sand raw material; S2. Weigh 1000 parts of the raw material after sieving in step S1 and add it to the mixing cylinder. Then add aluminum-containing compound and pore-forming agent. The aluminum-containing compound is used as an anti-crystallization and anti-deformation modifier, and the pore-forming agent is used as a bubble source. The doping amount of the aluminum-containing compound is calculated based on the Al element content. The aluminum-containing compound is aluminum hydroxide (aluminum element doping amount is 100 ppm), and the pore-forming agent is silicon nitride (doping amount is 2 wt%). Mix all materials thoroughly and evenly through the mixing cylinder to obtain a mixture. S3. Use a mold to shape the uniformly mixed mixture from step S2; S4. The calcined mixture is then subjected to an oxyhydrogen flame. S5. After calcination, allow the material to cool naturally. Once cooled, demold to obtain a milky white, opaque quartz glass blank. S6. According to the product drawings, the opaque quartz glass blank is machined. The machining process includes both hot and cold processing, such as polishing, cutting, sandblasting, etc., to obtain opaque quartz glass products with different application requirements. S7. Use a 7% (v / v) hydrofluoric acid solution and pure water to soak and rinse the milky white opaque quartz glass product, and let it air dry naturally. S8. The dried opaque quartz glass product is annealed and stress-relieved in a tunnel kiln to obtain the final opaque quartz glass product.

[0025] In step S2 above, high-purity quartz sand, aluminum-containing compounds, and pore-forming agents are weighed according to different proportion requirements, and all materials are uniformly mixed through a mixing cylinder and dried at 105-110℃ for 2-3 hours to remove adsorbed water. The aluminum hydroxide added in step S2 has a chemical purity of ≥99.99% to avoid introducing impurities that affect the purity of quartz glass. The silicon nitride added has a chemical purity of ≥99.9% and a particle size of 500-600 mesh.

[0026] In step S4 above, the temperature of the hydrogen-oxygen flame is 2200℃ and the calcination time is 40 min.

[0027] The cleaning step in step S7 above is as follows: After soaking the qualified milky white opaque quartz glass in a 7% hydrofluoric acid solution for 30 minutes, rinse it three times with pure water and let it air dry.

[0028] In step S8 above, the annealing temperature is 1050℃ and the holding time is 5 h.

[0029] Aluminum-doped opaque quartz glass, including milky white opaque quartz glass, was prepared by the above preparation method. The bubble pore size in the milky white opaque quartz glass is in the range of 5-150 μm.

[0030] When the thickness of the milky white opaque quartz glass is 10 mm, the whiteness is 90%.

[0031] Example 2

[0032] A method for manufacturing aluminum-doped opaque quartz glass, comprising the following steps: S1. Select 80-200 mesh high-purity quartz sand (purity ≥ 99.99%) as the matrix material, feed the raw material into a screening machine for repeated screening, and obtain 80-120 mesh quartz sand raw material; S2. Weigh 1000 parts of the sieved raw material from step S1 and add them to the mixing cylinder. Then add an aluminum-containing compound and a pore-forming agent. The aluminum-containing compound is used as an anti-crystallization and anti-deformation modifier, and the pore-forming agent is used as a bubble source. The doping amount of the aluminum-containing compound is calculated based on the Al element content. The aluminum-containing compound is aluminum hydroxide (aluminum element doping amount is 70 ppm), and the pore-forming agent is silicon nitride (doping amount is 0.5 wt%). Mix all materials thoroughly and evenly through the mixing cylinder to obtain a mixture. S3. Use a mold to shape the uniformly mixed mixture from step S2; S4. The calcined mixture is then subjected to an oxyhydrogen flame. S5. After calcination, allow the material to cool naturally. Once cooled, demold to obtain a milky white, opaque quartz glass blank. S6. According to the product drawings, the opaque quartz glass blank is machined. The machining process includes both hot and cold processing, such as polishing, cutting, sandblasting, etc., to obtain opaque quartz glass products with different application requirements. S7. Use a 7% (v / v) hydrofluoric acid solution and pure water to soak and rinse the milky white opaque quartz glass product, and let it air dry naturally. S8. The dried opaque quartz glass product is annealed and stress-relieved in a tunnel kiln to obtain the final opaque quartz glass product.

[0033] In step S2 above, high-purity quartz sand, aluminum-containing compounds, and pore-forming agents are weighed according to different proportion requirements, and all materials are uniformly mixed in a mixing cylinder and dried at 105-110℃ for 2-3 hours to remove adsorbed water. The chemical purity of the aluminum hydroxide added in step S2 is ≥ 99.99% to avoid introducing impurities that affect the purity of the quartz glass. The chemical purity of the added silicon nitride is ≥ 99.9%, and the particle size of the silicon nitride is 600-800 mesh.

[0034] In step S4 above, the temperature of the hydrogen-oxygen flame is 2200℃ and the calcination time is 30 min.

[0035] The cleaning step in step S7 above is as follows: After soaking the qualified milky white opaque quartz glass in a 7% hydrofluoric acid solution for 20 minutes, rinse it three times with pure water and let it air dry.

[0036] In step S8 above, the annealing temperature is 1050℃ and the holding time is 4 hours.

[0037] Aluminum-doped opaque quartz glass, including milky white opaque quartz glass, was prepared by the above preparation method. The bubble pore size in the milky white opaque quartz glass is in the range of 5-150 μm.

[0038] When the thickness of the milky white opaque quartz glass is 10 mm, the whiteness is 85%.

[0039] Example 3

[0040] A method for manufacturing aluminum-doped opaque quartz glass, comprising the following steps: S1. Select 80-200 mesh high-purity quartz sand (purity ≥ 99.99%) as the matrix material, feed the raw material into a screening machine for repeated screening, and obtain 160-200 mesh quartz sand raw material; S2. Weigh 1000 parts of the sieved raw material from step S1 and add them to the mixing cylinder. Then add an aluminum-containing compound and a pore-forming agent. The aluminum-containing compound acts as an anti-crystallization and anti-deformation modifier, and the pore-forming agent acts as a bubble source. The doping amount of the aluminum-containing compound is calculated based on the Al element content. The aluminum-containing compound is aluminum hydroxide (aluminum element doping amount is 120 ppm), and the pore-forming agent is silicon nitride (doping amount is 3 wt%). Mix all materials thoroughly and evenly through the mixing cylinder to obtain a mixture. S3. Use a mold to shape the uniformly mixed mixture from step S2; S4. The calcined mixture is then subjected to an oxyhydrogen flame. S5. After calcination, allow the material to cool naturally. Once cooled, demold to obtain a milky white, opaque quartz glass blank. S6. According to the product drawings, the opaque quartz glass blank is machined. The machining process includes both hot and cold processing, such as polishing, cutting, sandblasting, etc., to obtain opaque quartz glass products with different application requirements. S7. Use a 7% (v / v) hydrofluoric acid solution and pure water to soak and rinse the milky white opaque quartz glass product, and let it air dry naturally. S8. The dried opaque quartz glass product is annealed and stress-relieved in a tunnel kiln to obtain the final opaque quartz glass product.

[0041] In step S2 above, high-purity quartz sand, aluminum-containing compounds, and pore-forming agents are weighed according to different proportion requirements, and all materials are uniformly mixed in a mixing cylinder and dried at 105-110℃ for 2-3 hours to remove adsorbed water. The chemical purity of the aluminum hydroxide added in step S2 is ≥ 99.99% to avoid introducing impurities that affect the purity of the quartz glass. The chemical purity of the added silicon nitride is ≥ 99.9%, and the particle size of the silicon nitride is 500-600 mesh.

[0042] In step S4 above, the temperature of the hydrogen-oxygen flame is 2200℃ and the calcination time is 50 min.

[0043] The cleaning step in step S7 above is as follows: After soaking the qualified milky white opaque quartz glass in a 7% hydrofluoric acid solution for 30 minutes, rinse it three times with pure water and let it air dry.

[0044] In step S8 above, the annealing temperature is 1050℃ and the holding time is 6 hours.

[0045] Aluminum-doped opaque quartz glass, including milky white opaque quartz glass, was prepared by the above preparation method. The bubble pore size in the milky white opaque quartz glass is in the range of 5-150 μm.

[0046] When the thickness of the milky white opaque quartz glass is 10 mm, the whiteness is 92%.

[0047] The aluminum-doped opaque quartz glass and its manufacturing method provided by the present invention have been described above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the present invention and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An aluminum-doped opaque quartz glass, characterized in that, The opal opaque quartz glass comprises bubble holes with a pore size in the range of 5-150 μm.

2. The aluminum-doped opaque quartz glass according to claim 1, wherein The whiteness is 70-90% when the thickness of the opal opaque quartz glass is 10 mm.

3. A method of making the aluminum-doped opaque quartz glass of any one of claims 1-2, characterized in that, The method comprises the following steps: S1, selecting high-purity quartz sand as a base material; S2, adding an aluminum-containing compound and a pore-forming agent to the high-purity quartz sand selected in step S1, and mixing them thoroughly to obtain a mixture; S3, placing the mixture obtained in step S2 into a mold for shaping; S4, calcining the shaped mixture by using a hydrogen-oxygen flame; S5, naturally cooling the calcined mixture, and demolding the opal opaque quartz glass after natural cooling.

4. The method for manufacturing aluminum-doped opaque quartz glass according to claim 3, characterized in that, The method further comprises the following steps: S6, machining the opal opaque quartz glass obtained in step S5 according to product drawing requirements to obtain an opal opaque quartz glass product; S7, cleaning the opal opaque quartz glass product and naturally air-drying it; S8, annealing and stress relieving the dried opal opaque quartz glass product.

5. The method for manufacturing aluminum-doped opaque quartz glass according to claim 3, characterized in that, The purity of the aluminum-containing compound in step S2 is ≥99.99%, and the doping amount is 50-150 ppm; the purity of the pore-forming agent is ≥99.9%, the particle size is 500-800 mesh, and the doping amount is 0.1-5.0 wt%.

6. The method for manufacturing aluminum-doped opaque quartz glass according to claim 3, characterized in that, The aluminum-containing compound is one or more of aluminum hydroxide, aluminum nitrate, or aluminum oxide; and the pore-forming agent is one or more of silicon carbide, silicon nitride, or boron nitride.

7. The method for manufacturing aluminum-doped opaque quartz glass according to claim 3, characterized in that, The sintering time in step S4 is in the range of 30-60 min.

8. The method for manufacturing aluminum-doped opaque quartz glass according to claim 4, characterized in that, The cleaning operation in step S7 is as follows: placing the opal opaque quartz glass product that has passed the detection into a hydrofluoric acid solution with a volume fraction of 5-10% for 10-30 min, and then repeatedly rinsing it with pure water for several times.

9. The method for manufacturing aluminum-doped opaque quartz glass according to claim 4, characterized in that, The machining in step S6 is cold and hot machining, including polishing, cutting, and sandblasting.

10. The method for manufacturing aluminum-doped opaque quartz glass according to claim 4, characterized in that, The annealing temperature in step S8 is 1000-1100℃, and the annealing time is 4-8 h.

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