High-strength quartz sand ceramic material and preparation method and application thereof

Abstract

The application relates to a high-strength quartz sand ceramic material and a preparation method and application thereof. A multi-scale reinforcing network is constructed by gradient matching of quartz fibers and silicon carbide fibers, grain boundary sliding is inhibited, nano-scale micropores are formed on the fiber surfaces through HF acid etching, and the interface shear strength is improved by combining with a silane coupling agent bridge. In addition, the composite powder of Al2O3 and ZrO2 can inhibit abnormal grain growth in a sintering process through stage gradient sintering, that is, first stage degumming, second stage nucleation and third stage densification. Nano-crystalline grains are twisted through high-density dislocations and are pinned through a grain boundary pinning effect, so that the grain boundary sliding resistance is improved by 3 times. Meanwhile, Si-O-Al bonds are formed between excessive Al2O3 and modified fibers, which is beneficial to reducing the interface thermal resistance, improving the heat resistance of the material and avoiding thermal stress concentration.

Description

Technical Field

[0001] This invention relates to the field of lightweight building materials technology, and in particular to a high-strength quartz sand ceramic material and its preparation method. Background Technology

[0002] Quartz ceramic materials are widely used in aerospace, semiconductor and other fields due to their high temperature resistance and low dielectric loss. However, traditional materials have problems such as low strength, bending strength generally <50MPa, fracture toughness ≤0.8 MPa·m¹ / ², and poor thermal shock stability (cracking after ≤3 cycles of rapid cooling and heating). Moreover, existing molding processes (such as dry pressing and gel casting) are difficult to control porosity, resulting in a yield of only 75%. When reinforced with fiber, the dispersibility is poor (content ≤6wt.%), and grain growth agents can easily lead to a decrease in grain boundary strength, which limits their application in complex working conditions. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of low strength and poor thermal stability of quartz sand ceramic materials in the prior art. It provides a method that uses high-purity quartz sand, modified fiber, and Al2O3-ZrO2 grain growth agent in synergy, multi-stage ball milling dispersion, and vacuum impregnation molding and gradient sintering processes to construct a three-dimensional interpenetrating network structure. This method can improve the flexural strength of the material to 92MPa and prevent cracking after ≥10 water cooling cycles after 1200℃ thermal shock cycling.

[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution.

[0005] The first aspect of this invention provides a high-strength quartz sand ceramic material, made from the following raw materials in parts by weight: 85-90 parts high-purity quartz sand, 5-8 parts modified fiber, 1-3 parts grain grower, 0.5-1.5 parts dispersant, and 2-4 parts binder; wherein the modified fiber is a mixture of quartz fiber and silicon carbide fiber, and the grain grower is a composite powder of Al2O3 and ZrO2; the material is prepared by multi-stage ball milling dispersion, vacuum impregnation molding, and gradient sintering processes.

[0006] By using a mixture of quartz fiber and silicon carbide fiber as the modified fiber, the high-temperature resistance and high-temperature stability of the material are improved. The quartz fiber is arranged along the molding direction, and the silicon carbide fiber is arranged at a 45° cross to form a multi-level reinforcement network. The composite powder of Al2O3 and ZrO2 as the grain growth agent can inhibit abnormal grain growth during sintering, and the grain size can be controlled within 100 nanometers. This works synergistically with the reinforcement network to improve the yield strength of the material.

[0007] Furthermore, the quartz sand has a particle size D50 of 5-10 μm and a SiO2 purity of ≥99.9%.

[0008] Furthermore, the mass ratio of quartz fiber to silicon carbide fiber in the modified fiber is 4:1-1.5:1, and the average aspect ratio of the modified fiber is ≥50:1.

[0009] Furthermore, the modified fibers have an average aspect ratio of 50-80:1, ensuring both dispersibility and material toughness.

[0010] Furthermore, the modified fiber has an average aspect ratio of 50:1, at which point the coefficient of thermal expansion of the modified fiber is close to that of the Al2O3-ZrO2 interface, thus improving the material's thermal management capability.

[0011] Furthermore, the modified fiber has a mass ratio of quartz fiber to silicon carbide fiber of 7:3, which can ensure low thermal conductivity while maintaining high-temperature mechanical strength.

[0012] Furthermore, the mass ratio of Al2O3 to ZrO2 in the grain growth agent is 2:1-3:2, and the particle size is ≤1μm. On the one hand, the Al2O3 and ZrO2 inhibit grain growth during sintering, and on the other hand, the excess Al2O3 forms Si-O-Al bonds with the modified fibers, which helps to reduce interfacial thermal resistance, improve the heat resistance of the material, and avoid thermal stress concentration.

[0013] Furthermore, the dispersant is a polycarboxylate ammonium salt with an HLB value of 12-15.

[0014] Furthermore, the dispersant includes one or more of the following: ammonium polyacrylate, maleic acid-acrylic acid copolymer ammonium salt, polymethacrylate ammonium salt, and graft copolymerized polycarboxylate ammonium salt.

[0015] Furthermore, the adhesive is an acrylamide-acrylic acid copolymer.

[0016] Furthermore, the acrylamide-acrylic acid copolymer is one or more of the standard acrylamide-acrylic acid copolymer and the functionalized acrylamide-acrylic acid copolymer.

[0017] This invention also provides a method for preparing quartz sand ceramic material, comprising the following steps:

[0018] (1) Preparation of modified fibers: Quartz fibers and silicon carbide fibers are mixed, immersed in ethanol and ultrasonically treated, dried and then immersed in HF acid solution, stirred and reacted, filtered, washed with water and dried to obtain modified fibers;

[0019] (2) Mix the quartz sand with the grain growth agent to obtain a mixture;

[0020] (3) Add the modified fiber and dispersant to water, ultrasonically treat it, mix it with the binder, and ball mill it to form a slurry;

[0021] (4) Add the mixture from step (2) to the slurry from step (3), mix, impregnate, and dry to obtain a quartz sand ceramic matrix;

[0022] (5) The quartz sand ceramic matrix is ​​gradient sintered to obtain the quartz sand ceramic material.

[0023] Further, (1) Preparation of modified fiber: Quartz fiber and silicon carbide fiber are mixed in a mass ratio of 4:1-1.5:1, immersed in anhydrous ethanol, ultrasonically treated at 50-60℃ for 1-2 hours, vacuum dried, immersed in 30-60% HF acid solution, stirred for 0.5-1 hours, filtered and washed with water until neutral, and then dried to obtain the modified fiber.

[0024] Further, (2) the quartz sand and grain growth agent are added to the solvent and ball-milled together.

[0025] Furthermore, the solvent is anhydrous ethanol.

[0026] Further, (3) the modified fiber and dispersant from step (1) are added to deionized water, ultrasonically treated, mixed with binder, and subjected to multi-stage ball milling to form a high solids content slurry.

[0027] Further, (4) the mixture in step (2) is added to step (3) and mixed evenly, and then vacuum impregnation and drying are performed in sequence to obtain quartz sand ceramic matrix.

[0028] Further, (5) the quartz sand ceramic matrix from step (4) is subjected to gradient sintering:

[0029] First stage: Heat to 50-200℃ at a heating rate of 5-10℃ / min to remove volatile moisture;

[0030] Second stage: Heat to 200-800℃ at a heating rate of 3-5℃ / min and hold for 1-5 hours;

[0031] The third stage involves heating the material to 800-1250℃ at a rate of 10-15℃ / min and holding it at that temperature for 1.5-5 hours to obtain the quartz sand ceramic material.

[0032] Further, in step (1), the modified fiber is prepared as follows: quartz fiber and silicon carbide fiber are mixed in a mass ratio of 4:1-1.5:1, immersed in anhydrous ethanol, ultrasonically treated at 50-60℃ for 1-2 hours, vacuum dried, and then immersed in a 30-60% HF acid solution. The mixture is stirred and reacted for 0.5-1 hours, filtered, washed with water until neutral, dried, and then placed in an organosilicon coupling agent solution. After standing, it is vacuum dried to obtain the modified fiber. By cleaning with ethanol and then immersing in the HF acid solution, micropores are formed on the reaction surface, improving the interfacial bonding strength.

[0033] Furthermore, the multi-stage ball milling time in step (3) is 6-12 hours, and the multi-stage ball milling includes coarse grinding and fine grinding. In the coarse grinding process, steel balls with a diameter of 10-15 mm are used for particle crushing, and in the fine grinding process, steel balls with a diameter of 3-5 mm are used for particle refinement.

[0034] Furthermore, the vacuum impregnation step first uses 5-10MPa for pre-pressing and shaping, and then uses 180-220MPa for cold isostatic pressing.

[0035] The quartz sand ceramic material described in this invention is widely used in the fields of construction, machinery, and aviation.

[0036] The present invention has the following advantages over the prior art:

[0037] This invention achieves a leapfrog improvement in the performance of quartz sand ceramic materials through the synergistic effect of raw material system innovation, process optimization, and interface design.

[0038] Quartz fibers (low-temperature elastic phase) and silicon carbide fibers (high-temperature rigid phase) are mixed in a gradient ratio to construct a multi-scale reinforcement network. At low temperatures, quartz fibers provide plastic deformation capability and absorb energy; at high temperatures, silicon carbide fibers form a rigid skeleton, and the SiO2 glass phase generated by SiC oxidation chemically bonds with the matrix, inhibiting grain boundary slip.

[0039] The fiber surface is etched with HF acid to form nanoscale micropores, which are then bridged by a silane coupling agent, thus improving the interfacial shear strength. Simultaneously, the Al2O3 / ZrO2 composite powder can undergo staged gradient sintering during the sintering process—namely, debinding in the first stage, nucleation in the second stage, and densification in the third stage—to suppress abnormal grain growth, controlling the grain size to 50-100 nm, a 62.5% reduction compared to traditional processes. The nanocrystals, through high-density dislocation entanglement and grain boundary pinning effects, increase grain boundary slip resistance.

[0040] HF acid etching combined with silane coupling agent treatment achieves a fiber-matrix interface bonding strength of 25 MPa. The mixed solvent effectively extracts alkali metal impurities from the quartz sand, and the chemical adsorption of alkali metals by Al2O3-ZrO2 increases the resistivity. The gradient sintering process achieves a material density of 98.5%, a pore size of <1 μm, and a 60% reduction in thermal stress.

[0041] Synergistic effects of processes: Multi-stage ball milling achieves a particle uniformity CV value ≤5%, while vacuum impregnation combined with staged heating significantly improves the densification efficiency of the green body. The final material achieves a flexural strength of 92MPa and exhibits no cracking after 12 thermal shock cycles, demonstrating comprehensive performance breakthroughs over existing technological bottlenecks.

[0042] This invention provides a new paradigm for the development of high-performance ceramic materials in extreme environments through the innovative coupling of microstructure design and macro process control. Detailed Implementation

[0043] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0044] Example 1

[0045] Example 1 of the present invention: The present invention is based on the fact that high-strength quartz sand ceramic material belongs to lightweight building materials, and provides a high-strength quartz sand ceramic material, which, by weight, includes the following raw materials: 85 parts of high-purity quartz sand (D50=8μm, SiO2 purity is 99.9%), 6 parts of modified fiber, 1 part of composite powder of Al2O3 and ZrO2, 1 part of polycarboxylate ammonium salt (ZH-6010, Huangshan Zhonghao), and 2 parts of acrylamide-acrylic acid copolymer (CAS 9003-06-9, Hubei Gaide Chemical).

[0046] Another aspect of Embodiment 1 of the present invention provides a method for preparing a high-strength quartz sand ceramic material, comprising the following preparation steps: raw materials are proportioned according to the above-mentioned ratio.

[0047] (1) Preparation of modified fiber: Quartz fiber (domestic QF-300, average length 300μm, average diameter 6μm) and silicon carbide fiber (domestic SCS-6, average length 350μm, average diameter 7μm) were mixed in a mass ratio of 7:3, immersed in anhydrous ethanol, ultrasonically treated at 50℃ (frequency 40kHz, power 200W) for 1 hour, vacuum dried at 60℃ for 2 hours, immersed in 30% HF acid solution, stirred for 0.6 hours, filtered, washed with water until neutral, placed in organosilicon coupling agent solution (KH-570, weight concentration 2%, solvent is anhydrous ethanol) and stood for 2 hours, vacuum dried at 80℃ for 3 hours to obtain the modified fiber;

[0048] (2) High-purity quartz sand (D50=8μm, SiO2 purity is 99.9%) and grain growth agent (Al2O3:ZrO2=2:1, average particle size of both is 0.5μm) were added to anhydrous ethanol and ball-milled. First, 10mm steel balls were used for coarse grinding at 200rpm for 6h, and then 5mm steel balls were used for fine grinding at 300rpm for 6h to obtain a 62vol.% mixture slurry (D50=8.2μm, CV=5%).

[0049] (3) The modified fiber in step (1) is added to deionized water and ultrasonically treated with a power of 300W for 20 minutes to obtain an ammonia polyacrylic acid solution (0.5wt.%). This solution is then mixed with an acrylamide-acrylic acid copolymer and first coarsely ground with an 8mm steel ball at 200rpm for 3 hours, and then finely ground with a 5mm steel ball at 300rpm for 3 hours to form a slurry.

[0050] (4) Add the mixture slurry from step (2) to step (3). The mixture slurry and the slurry from step (3) are placed in a mixing tank and stirred at 50 rpm for 3 hours to mix evenly. Then, vacuum impregnation (first 5 MPa pre-pressing for 5 min, then 180 MPa cold isostatic pressing for 10 min), demolding, and drying are performed sequentially to obtain a quartz sand ceramic matrix.

[0051] (5) The quartz sand ceramic matrix from step (4) is subjected to gradient sintering:

[0052] First stage: Heat to 200℃ at a heating rate of 5℃ / min to remove volatile moisture;

[0053] Second stage: Heat to 800℃ at a heating rate of 3℃ / min and hold for 3 hours;

[0054] The third stage: the temperature is increased to 1250℃ at a heating rate of 15℃ / min and held for 3 hours to obtain quartz sand ceramic material.

[0055] Example 2

[0056] The difference between Example 2 and Example 1 is that no organosilicon coupling agent was added in step (1).

[0057] Example 3

[0058] The difference between Example 3 and Example 1 is that the mass ratio of quartz fiber to silicon carbide fiber is 4:1.

[0059] Example 4

[0060] The difference between Example 4 and Example 1 is that the mass ratio of quartz fiber to silicon carbide fiber is 3:2.

[0061] Example 5

[0062] The difference from Example 1 is that the mass ratio of Al2O3 to ZrO2 is 3:2.

[0063] Example 6

[0064] The difference from Example 1 lies in step (5).

[0065] First stage: Heat to 200℃ at a heating rate of 10℃ / min to remove volatile moisture;

[0066] Second stage: Heat to 800℃ at a heating rate of 3℃ / min and hold for 3 hours;

[0067] The third stage: the temperature is increased to 1250℃ at a heating rate of 15℃ / min and held for 3 hours to obtain quartz sand ceramic material.

[0068] Example 7

[0069] The difference from Example 1 lies in step (5).

[0070] First stage: Heat to 200℃ at a heating rate of 5℃ / min to remove volatile moisture;

[0071] Second stage: Heat to 500℃ at a heating rate of 3℃ / min and hold for 3 hours;

[0072] The third stage: the temperature is increased to 800℃ at a heating rate of 15℃ / min and held for 3 hours to obtain quartz sand ceramic material.

[0073] Example 8

[0074] The difference from Example 1 is that the mass ratio of quartz fiber to silicon carbide fiber is 5:1.

[0075] Comparative Example 1

[0076] A high-strength quartz sand ceramic material, by weight, comprises the following raw materials: 85 parts of high-purity quartz sand (D50=8μm, SiO2 purity is 99.9%), 6 parts of quartz fiber, 1 part of composite powder of Al2O3 and ZrO2, 1 part of ammonium polycarboxylate salt, and 2 parts of acrylamide-acrylic acid copolymer.

[0077] Another aspect of Embodiment 1 of the present invention provides a method for preparing a high-strength quartz sand ceramic material, comprising the following preparation steps:

[0078] (1) Preparation of quartz fiber: Quartz fiber (domestic QF-300, average length 300μm, average diameter 6μm) was immersed in anhydrous ethanol, ultrasonically treated at 50℃ (frequency 40kHz, power 200W) for 1 hour, vacuum dried at 60℃ for 2 hours, then immersed in 30% HF acid solution, stirred for 0.6 hours, filtered, washed with water until neutral, and then placed in organosilicon coupling agent solution (KH-570, weight concentration 2%, solvent is anhydrous ethanol) for 2 hours, and vacuum dried at 80℃ for 3 hours to obtain modified quartz fiber;

[0079] (2) High-purity quartz sand (D50=8μm, SiO2 purity is 99.9%) and grain growth agent (Al2O3:ZrO2=2:1, particle size 0.5μm) were ball-milled and mixed. First, 10mm steel balls were used to coarsely grind at 200rpm for 6h, and then 5mm steel balls were used to finely grind at 300rpm for 6h to obtain 62vol.% composite powder slurry (D50=8.2μm, CV=5%).

[0080] (3) The modified fiber in step (1) is added to deionized water and ultrasonically treated with a power of 300W for 20 minutes to obtain an ammonia polyacrylic acid solution (0.5wt.%). This solution is then mixed with an acrylamide-acrylic acid copolymer and first coarsely ground with an 8mm steel ball at 200rpm for 3 hours, and then finely ground with a 5mm steel ball at 300rpm for 3 hours to form a slurry.

[0081] (4) Add the mixture slurry from step (2) to step (3). The mixture slurry and the slurry from step (3) are placed in a mixing tank and stirred at 50 rpm for 3 hours to mix evenly. Then, vacuum impregnation (first 5 MPa pre-pressing for 5 min, then 180 MPa cold isostatic pressing for 10 min), demolding, and drying are performed sequentially to obtain a quartz sand ceramic matrix.

[0082] (5) The quartz sand ceramic matrix from step (4) is subjected to gradient sintering:

[0083] First stage: Heat to 200℃ at a heating rate of 5℃ / min to remove volatile moisture;

[0084] Second stage: Heat to 800℃ at a heating rate of 3℃ / min and hold for 3 hours;

[0085] The third stage: the temperature is increased to 1250℃ at a heating rate of 15℃ / min and held for 3 hours to obtain quartz sand ceramic material.

[0086] Comparative Example 2

[0087] The difference from Comparative Example 1 is that the quartz fiber was replaced with silicon carbide fiber (domestic SCS-6, average length 350μm, average diameter 7μm).

[0088] Comparative Example 3

[0089] The difference from Example 1 is that the grain growth agent is only ZrO2.

[0090] Comparative Example 4

[0091] The difference from Example 1 is that the grain growth agent is only Al2O3.

[0092] Comparative Example 5

[0093] The difference from implementation 1 is that step (5) involves sintering the quartz sand ceramic matrix in step (4) once: heating it to 1250℃ at a heating rate of 15℃ / min and holding it for 6 hours.

[0094] Comparative Example 6

[0095] The difference from Example 1 is that low-purity quartz sand with a SiO2 content of 98% is used.

[0096] Performance testing:

[0097] The bending strength was tested according to ASTM C1161; the dielectric constant and loss tangent were tested according to ASTM D2520-95; the fracture toughness was tested according to ASTM E1820-21; and the thermal shock stability was tested using the water quenching method according to ASTM C1171-21 (heating to 1200℃, holding for 20 min, rapid water quenching to room temperature to check for cracking, cyclic testing until cracking, and recording the number of cycles at cracking). The test data are detailed in Table 1.

[0098] Table 1 Performance test results of Examples 1-8 and Comparative Examples 1-6

[0099]

[0100] According to the experimental results of Example 1, the gradient ratio of quartz fiber and silicon carbide fiber and the synergy of nanocrystals significantly improved the flexural strength and fracture toughness. The composite powder of Al2O3 and ZrO2 could inhibit grain growth during sintering, improve the interfacial properties of the material, and thus improve the thermal stability of the material. However, Comparative Example 1, lacking the high-temperature support of silicon carbide fiber, experienced a sharp drop in strength at high temperatures, and cracked after only 2 thermal shock cycles. Comparative Example 2, with only silicon carbide fiber added, had low toughness. Example 8, with excessive quartz fiber content, improved flexural strength and fracture toughness compared to Comparative Example 2, but the grain size increased, the interfacial properties decreased, and the dielectric constant and thermal stability were somewhat reduced. Comparative Example 3, without ZrO2 synergy, resulted in grain coarsening. Comparative Example 4, without Al2O3 synergy, suffered from deteriorated dielectric properties. Comparative Example 5, using a single sintering process, resulted in excessive porosity and reduced overall performance. Comparative Example 6, using low-purity quartz sand, resulted in grain boundary defects. In summary, this invention creatively combines quartz fiber and silicon carbide fiber in a gradient ratio and controls the amount of each ratio. By utilizing multi-stage ball milling and gradient sintering processes, it achieves a leapfrog improvement in the performance of quartz sand ceramic materials.

[0101] The analytical methods involved in the invention have been described in detail. It should be noted that the above description is only to help those skilled in the art better understand the methods and ideas of the invention, and is not intended to limit the scope of the invention. Those skilled in the art can make appropriate adjustments or modifications to the invention without departing from its principles, and such adjustments and modifications should also fall within the protection scope of the invention.

Claims

1. A high-strength quartz sand ceramic material, characterized in that, It is made from the following raw materials in parts by weight: 85-90 parts high-purity quartz sand, 5-8 parts modified fiber, 1-3 parts grain grower, 0.5-1.5 parts dispersant, and 2-4 parts binder; the modified fiber is a mixture of quartz fiber and silicon carbide fiber, and the grain grower is a composite powder of Al2O3 and ZrO2; the high-strength quartz sand ceramic material is prepared by multi-stage ball milling dispersion, vacuum impregnation molding, and gradient sintering process; The preparation method of the high-strength quartz sand ceramic material includes the following steps: (1) Preparation of modified fibers: Quartz fibers and silicon carbide fibers are mixed, immersed in ethanol and ultrasonically treated, dried and then immersed in HF acid solution, stirred and reacted, filtered, washed with water and dried to obtain modified fibers. (2) Mix high-purity quartz sand with a grain growth agent to obtain a mixture; (3) Add the modified fiber and dispersant to water, ultrasonically treat it, mix it with the binder, and ball mill it to form a slurry; (4) Add the mixture from step (2) to the slurry from step (3), mix, impregnate, and dry to obtain a quartz sand ceramic matrix; (5) The quartz sand ceramic matrix in step (4) is subjected to gradient sintering: First stage: heating to 50-200℃ at a heating rate of 5-10℃ / min to remove volatile moisture; Second stage: heating to 200-800℃ at a heating rate of 3-5℃ / min and holding for 1-5 hours; Third stage: heating to 800-1250℃ at a heating rate of 10-15℃ / min and holding for 1.5-5 hours to obtain the quartz sand ceramic material.

2. The quartz sand ceramic material according to claim 1, characterized in that, The mass ratio of quartz fiber to silicon carbide fiber in the modified fiber is 4:1-1.5:1, and the average aspect ratio of the modified fiber is ≥50:

1.

3. The quartz sand ceramic material according to claim 1, characterized in that, The mass ratio of Al2O3 to ZrO2 in the grain growth agent is 2:1-3:2, and the particle size is ≤1μm.

4. The high-strength quartz sand ceramic material according to claim 1, characterized in that, The dispersant is a polycarboxylic acid ammonium salt with an HLB value of 12-15.

5. The quartz sand ceramic material according to claim 1, characterized in that, The adhesive is an acrylamide-acrylic acid copolymer.

6. The high-strength quartz sand ceramic material according to claim 1, characterized in that, In (1), the modified fiber is prepared by mixing quartz fiber and silicon carbide fiber in a mass ratio of 4:1-1.5:1, immersing them in anhydrous ethanol, ultrasonically treating them at 50-60℃ for 1-2 hours, vacuum drying them, immersing them in 30-60% HF acid solution, stirring and reacting them for 0.5-1 hours, filtering and washing them with water until neutral, and then drying them to obtain the modified fiber. And / or, in (2), high-purity quartz sand and grain growth agent are added to a solvent and ball-milled to obtain a slurry mixture; And / or, in (3), the modified fiber and dispersant in step (1) are added to deionized water, ultrasonically treated, mixed with binder, and subjected to multi-stage ball milling to form a high solids content slurry; And / or, in (4), the mixture in step (2) is added to step (3) and mixed evenly, and then vacuum impregnation and drying are performed in sequence to obtain quartz sand ceramic matrix.

7. The high-strength quartz sand ceramic material according to claim 6, characterized in that, Preparation of modified fibers in step (1): Quartz fibers and silicon carbide fibers are mixed in a mass ratio of 4:1-1.5:1, immersed in anhydrous ethanol, ultrasonically treated at 50-60℃ for 1-2 hours, vacuum dried, immersed in 30-60% HF acid solution, stirred and reacted for 0.5-1 hours, filtered and washed with water until neutral, dried, and then placed in organosilicon coupling agent solution. After standing, vacuum drying is performed to obtain the modified fibers. And / or, the multi-stage ball milling time in step (3) is 6-12 hours, and the multi-stage ball milling includes coarse grinding and fine grinding. In the coarse grinding process, steel balls with a diameter of 10-15 mm are used for particle crushing, and in the fine grinding process, steel balls with a diameter of 3-5 mm are used for particle refinement.

8. The quartz sand ceramic material according to claim 1, characterized in that, The high-purity quartz sand has a particle size D50 of 5-10 μm and a SiO2 purity of ≥99.9%.

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