Method for preparing high-strength and high-compactness quartz fiber reinforced quartz composite material

Abstract

The invention discloses a method for preparing a high-strength and high-compactness quartz fiber reinforced quartz composite material, and belongs to the technical field of quartz materials.The preparation method comprises the steps that a quartz fiber pre-woven body is subjected to heat treatment for 130-240 min at the temperature of 400-600 DEG C, and a pre-treated body is obtained; putting the pretreated body into a mold, vacuumizing until the pressure is less than 96 kPa, injecting the composite sol, and dipping for 60-120 minutes; keeping the sol liquid level to immerse the top of the pretreatment body, applying a pulsating pressure field of 0.2-0.5 MPa, and drying at 30-50 DEG C for 450-900 minutes to form a blank; and densifying and sintering the blank. The pulsating pressure field drives the sol to directionally migrate and keep the liquid level constant, so that the process operation is simplified, the penetration depth of a high component is remarkably improved, and the uniformity of a matrix is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of quartz materials, and particularly relates to a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material. Background Art

[0002] Quartz fiber-reinforced quartz matrix composites play an irreplaceable role in the field of aerospace wave-transmitting components due to their excellent dielectric properties, thermal stability, and mechanical strength. Currently, the mainstream preparation process uses the sol-gel method, and densification is achieved through repeated impregnation-drying cycles of the quartz fiber preform with acid silica sol. Existing technologies such as the patent CN118026717B have made progress in improving the impregnation efficiency through a staged liquid level lowering capillary impregnation process, but there are still significant limitations.

[0003] In this process, the height of capillary action is limited within 200 mm. For large components with a height exceeding 500 mm, the sol is difficult to effectively penetrate to the core area by capillary force, resulting in a sharp increase in the axial density of the component and seriously affecting the uniformity of product performance. In addition, to maintain the capillary infiltration effect, multiple manual operations of discharging the sol are required, which not only prolongs the process cycle but also introduces air into the system due to frequent opening, forming bubble defects inside the preform and reducing the structural reliability of the material.

[0004] Therefore, it is difficult for the existing technology to balance the impregnation uniformity and operation simplicity of large components: on the one hand, the intrinsic height limitation of capillary action restricts the upper limit of product size, and on the other hand, complex manual intervention steps increase the quality risk and production cost. There is an urgent need to develop a new preparation method that can break through the capillary height limitation and simplify the operation process. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material, including: S1. Heat-treating a quartz fiber preform at 400 - 600 °C for 130 - 240 min to obtain a pre-treated body; S2. Placing the pre-treated body in a mold, evacuating to a vacuum degree < 96 kPa, and then injecting a composite sol, and impregnating for 60 - 120 min; S3. Keeping the liquid level of the composite sol submerging the top of the pre-treated body, applying a pulsating pressure field of 0.2 - 0.5 MPa, and drying at 30 - 50 °C for 450 - 900 min to form a blank; S4. Sequentially performing densification treatment and sintering treatment on the blank.

[0006] In some embodiments, the pressure change period of the pulsating pressure field in S3 is 30 s for pressure increase / 60 s for pressure decrease.

[0007] In some embodiments, the composite sol comprises: 40-45 parts by mass of acid silica sol, 3-8 parts by mass of ZrO2 sol, and the viscosity of the composite sol < 15 mPa·s.

[0008] In some embodiments, the pressure range of the pulsating pressure field is 0.3-0.4 MPa.

[0009] In some embodiments, the addition amount of the ZrO2 sol is 5-7 parts by mass.

[0010] In some embodiments, after the drying of S3 is completed, the bottom 20-50 mm area of the blank is cut off.

[0011] In some embodiments, the height of the quartz fiber preform is 500-1500 mm, and the thickness is 6-30 mm.

[0012] In some embodiments, the specific steps of S4 include: S41, vacuum impregnating the blank in 40-45% acid silica sol for 60-120 min, and drying at 150-200 °C for 100-150 min; S42, vacuum impregnating the blank in 20-30% acid silica sol for 60-120 min; S43, sintering at 700-800 °C for 200-300 min.

[0013] In some embodiments, the vacuum degree of both S41 and S42 is 100 kPa.

[0014] In some embodiments, in S43, after the sintering, heat preservation is further included, and the heat preservation duration is 150-200 min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. By applying a pulsating pressure field of 0.2-0.5 MPa and keeping the sol liquid level constant, manual discharge is cancelled, so that the operation process is simplified, bubble defects are reduced, the penetration depth is increased, and high components are completely filled.

[0016] 2. Through the composite formula with the addition of 3-8 parts by mass of ZrO2 sol, the wettability of the sol is enhanced, the penetration efficiency is improved, and the density deviation rate in the height direction is reduced.

[0017] 3. Through staged concentration impregnation, the dense effect of the traditional 5-7 cycles can be achieved with only two impregnations, and the matrix density is uniform.

[0018] 4. By cutting off the bottom 20-50 mm area of the blank, the density gradient caused by gravity sedimentation is specifically eliminated, and the overall uniformity is improved with less material loss.

[0019] 5. By means of pulsating pressure cycle in coordination with low-temperature drying, the directional migration and solidification of the sol in the pores are completed synchronously, avoiding the deformation of the fiber skeleton and ensuring the mechanical integrity of the product. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0021] The present invention provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material, including: S1. Heat-treat the quartz fiber preform at 400 - 600 °C for 130 - 240 min to obtain a pre-treated body; S2. Place the pre-treated body in a mold, evacuate to a vacuum degree < 96 kPa, and then inject a composite sol, and impregnate for 60 - 120 min; S3. Keep the liquid level of the composite sol submerging the top of the pre-treated body, apply a pulsating pressure field of 0.2 - 0.5 MPa, and dry at 30 - 50 °C for 450 - 900 min to form a blank; S4. Perform densification treatment and sintering treatment on the blank in sequence.

[0022] In S1, the quartz fiber preform is heat-treated at 400 - 600 °C for 130 - 240 min to remove the sizing agent and organic impurities on the fiber surface. This process activates the fiber surface, improves the interfacial bonding force with the subsequent sol, and at the same time eliminates the capillary action hindrance caused by impurities, creating a clean pore channel for the penetration of the sol.

[0023] In S2, after the pre-treated body is placed in the mold, it is evacuated. The negative pressure environment discharges the trapped gas in the fiber pores, forming a low-pressure infiltration path. The injected composite sol quickly fills the pores under the pressure difference drive, and the 60 - 120 min impregnation ensures that the sol fully occupies the microscopic pore network. This step breaks through the capillary height limit of traditional static impregnation and lays a foundation for the subsequent directional migration.

[0024] In S3, first, the pulsating pressure field drives the directional migration. Boosting period (0.2 - 0.5 MPa): The external pressure field applies a positive pressure to the surface of the composite sol, forcing the sol to directionally migrate along the internal capillary network of the pretreatment body towards the unsaturated area at the top. The high-pressure environment overcomes the viscous resistance of the sol itself and the frictional resistance of the capillary wall, driving the sol to break through the height limit of traditional capillary action (>200 mm) and achieve deep penetration. Depressurizing period: The sudden pressure drop causes the dissolved gas in the sol to precipitate due to supersaturation. At the same time, the bubbles retained in the pores of the pretreatment body escape reversely along the capillaries under the pressure difference. This process clears the gas obstacles blocking the channels and restores the capillary penetration path. Then, low-temperature drying and curing are carried out. The solvent is slowly evaporated in an environment of 30 - 50°C, and the sol particles are orderly stacked in the capillaries to form a dense gel skeleton. During the boosting period, the liquid sol is pushed to supplement the microvoids generated by drying shrinkage. During the depressurizing period, the volatile components released during the formation of the gel skeleton are discharged, and finally a dense blank matrix with no density difference is formed. The drying process and the pulsating pressure act synergistically to ensure the uniform distribution of the gel in the pores and eliminate the density difference between the core and the surface.

[0025] In S4, the densification treatment is carried out by secondary infiltration and micropore filling, and sintering converts the gel into a continuous quartz phase, finally achieving the strong and tough bonding between the matrix and the fibers.

[0026] By driving the directional migration of the sol through the pulsating pressure field and keeping the liquid level constant, the process operation is simplified, the penetration depth of high components is significantly increased, and the matrix uniformity is enhanced.

[0027] In some embodiments, the pressure change period of the pulsating pressure field in S3 is 30 s for boosting / 60 s for depressurizing.

[0028] Repeatedly acting with a cycle of 30 s for boosting / 60 s for depressurizing forms a directional pressure. Each boosting cycle pushes the sol to supplement and fill the high-resistance areas (such as the cross-nodes of fiber bundles, the blind ends of micropores); the depressurizing stage creates space for the next cycle of penetration by gas discharge. The cyclic action continues until drying is completed, achieving the uniform distribution of the sol in the height direction (500 - 1500 mm).

[0029] During the working process of the pulsating pressure field, it replaces the function of the liquid level drop of manual discharge. The boosting simulates the penetration drive of "liquid level rise", and the depressurizing simulates the gas discharge of "exposed drying", but there is no risk of gas intrusion throughout the process. The sol at the top of the pretreatment body is always maintained immersed, eliminating the disturbance of the air-sol interface caused by the liquid level drop. The sol in the high-pressure area (near the liquid surface) is forced to migrate towards the low-pressure area (the top), automatically balancing the sedimentation of the sol caused by gravity and overcoming the defect of discontinuous filling caused by manual discharge.

[0030] In some embodiments, the composite sol contains: 40 - 45 parts by mass of acid silica sol, 3 - 8 parts by mass of ZrO2 sol, and the viscosity of the composite sol < 15 mPa·s.

[0031] The composite sol provides a high-solid-content matrix through 40-45 parts by mass of acid silica sol. At the same time, 3-8 parts by mass of ZrO2 sol is introduced to reduce the contact angle at the liquid-solid interface, enhancing the spreading ability of the sol on the inner wall of the capillary. Under the condition of maintaining the viscosity < 15 mPa·s, this ratio not only breaks through the solid content of traditional acid silica sol but also improves the longitudinal migration efficiency of the sol through the wetting modification of ZrO2, achieving uniform filling of high components (500-1500 mm) in a single impregnation and reducing the number of subsequent densification treatments.

[0032] In some embodiments, the pressure range of the pulsating pressure field is 0.3-0.4 MPa. The addition amount of the ZrO2 sol is 5-7 parts by mass.

[0033] By defining the pulsating pressure field of 0.3-0.4 MPa and the ZrO2 sol of 5-7 parts by mass, it not only ensures the migration efficiency of the sol breaking through high-resistance pores under high-pressure drive but also avoids the deformation of the fiber skeleton caused by excessive pressure. At the same time, the optimized addition amount of ZrO2 achieves a balance between significantly reducing the contact angle and maintaining the viscosity stability of the sol, thus realizing complete filling of the pores of high components on the premise of reducing process fluctuations and reducing the risk of gelation caused by sol agglomeration.

[0034] In some embodiments, after the drying of S3, the bottom 20-50 mm area of the blank is cut off. The height of the quartz fiber preform is 500-1500 mm, and the thickness is 6-30 mm.

[0035] In some embodiments, the height of the quartz fiber preform is 1500 mm, and the thickness is 18 mm.

[0036] By cutting off the bottom 20-50 mm area of the blank, the uneven part of the sol settlement caused by gravity in the 500-1500 mm high component is eliminated, while the main uniform structure formed by the pulsating pressure field is retained. This operation only cuts off the bottom < 10% area, ensuring the density consistency of the overall product at the cost of minimal material loss and avoiding the attenuation of the core-surface performance caused by the increase in height in traditional processes. It should be noted that the height of the quartz fiber preform refers to the length direction of the capillary channels in the quartz fiber, and the thickness is the cross-sectional dimension perpendicular to the height.

[0037] In some embodiments, the specific steps of S4 include: S41. Vacuum impregnate the blank in 40-45% acid silica sol for 60-120 min, and dry it at 150-200 °C for 100-150 min; S42. Vacuum impregnate the blank in 20-30% acid silica sol for 60-120 min; S43. Sinter at 700-800 °C for 200-300 min.

[0038] In some embodiments, the vacuum degrees of S41 and S42 are both 100 kPa.

[0039] In some embodiments, in S43, after sintering, heat preservation is further included, and the heat preservation duration is 150 - 200 min.

[0040] In S41, first, the blank is impregnated with 40 - 45% high - concentration acid silica sol under 100 kPa vacuum. Utilizing the high - solid - content characteristic, it preferentially occupies large - size pores and constructs a dense skeleton. Medium - temperature drying and curing of the main structure are carried out at 150 - 200 °C while retaining capillary channels. In S42, subsequently, it is switched to 20 - 30% low - concentration acid silica sol for secondary impregnation. Its low - viscosity characteristic enables it to penetrate into the fine pores that were not filled in the previous stage, and the same vacuum degree (100 kPa) maintains the penetration path unobstructed. In S43, sintering is carried out at 700 - 800 °C for 200 - 300 min, and combined with 150 - 200 min of heat preservation, amorphous SiO2 is transformed into a continuous quartz phase. At the same time, the previously introduced ZrO2 component inhibits the cristobalite phase transformation and reduces thermal stress cracks. This process uses a step - by - step filling mechanism of building a skeleton with high concentration and filling micro - pores with low concentration, replaces traditional multiple cycles with two impregnations, and the constant vacuum environment and optimized heat preservation duration ensure the thermodynamic balance of the phase - change process, eliminating local over - burning or under - burning defects.

[0041] The method of the present invention will be described in detail below with reference to examples, comparative examples and experimental data.

[0042] Example 1 This example provides a method for preparing a high - strength and high - density quartz fiber - reinforced quartz composite material, including the following steps: S1. Take a quartz fiber pre - woven body with a height of 1000 mm and a thickness of 18 mm, place the pre - woven body in an electric furnace, heat it at a rate of 10 °C / min to 500 °C, and keep it warm for 185 min to obtain a pre - treated body.

[0043] S2. Load the pre - treated body into a steel mold with a sealed cover, evacuate to 94 kPa, inject the composite sol, and impregnate for 90 min. Among them, the composite sol is 42.5 parts by mass of acid silica sol + 5.5 parts by mass of ZrO2 sol, and the viscosity is 12 mPa·s.

[0044] S3. Keep the sol liquid level submerging the top of the pre - treated body, connect the compressed air system to apply a pulsating pressure of 0.35 MPa, and operate according to the cycle of increasing pressure for 30 s / decreasing pressure for 60 s. Continuously dry at 40 °C for 675 min to form a blank. After drying, cut off a 35 - mm area at the bottom of the blank.

[0045] S41. Immerse the blank in 42.5% acid silica sol under 100 kPa vacuum for 90 min, take it out and dry at 175 °C for 125 min; S42. Immerse it again in 25% acid silica sol under 100 kPa vacuum for 90 min; S43. Place it in an electric furnace and sinter at 750 °C for 250 min, keep the temperature for 175 min to obtain a high-strength and high-density quartz fiber reinforced quartz composite material.

[0046] Example 2 This example provides a method for preparing a high-strength and high-density quartz fiber reinforced quartz composite material, including the following steps: S1. Take a quartz fiber preform with a height of 1000 mm and a thickness of 18 mm, place the preform in an electric furnace, and heat it up to 400 °C at a rate of 10 °C / min, keep the temperature for 130 min to obtain a pre-treated body.

[0047] S2. Load the pre-treated body into a steel mold with a sealed cover, evacuate to 94 kPa, inject the composite sol, and impregnate for 60 min. Among them, the composite sol is 40 parts by mass of acid silica sol + 3 parts by mass of ZrO2 sol, and the viscosity is 12 mPa·s.

[0048] S3. Keep the liquid level of the sol submerging the top of the pre-treated body, connect the compressed air system to apply a pulsating pressure of 0.2 MPa, and operate in a cycle of increasing pressure for 30 s / decreasing pressure for 60 s. Continuously dry at 30 °C for 450 min to form a blank. After drying, cut off a 20 mm area at the bottom of the blank.

[0049] S41. Immerse the blank in 40% acid silica sol under 100 kPa vacuum for 60 min, take it out and dry at 150 °C for 100 min; S42. Immerse it again in 20% acid silica sol under 100 kPa vacuum for 60 min; S43. Place it in an electric furnace and sinter at 700 °C for 200 min, keep the temperature for 150 min to obtain a high-strength and high-density quartz fiber reinforced quartz composite material.

[0050] Example 3 This example provides a method for preparing a high-strength and high-density quartz fiber reinforced quartz composite material, including the following steps: S1. Take a quartz fiber preform with a height of 1000 mm and a thickness of 18 mm, place the preform in an electric furnace, and heat it up to 600 °C at a rate of 10 °C / min, keep the temperature for 240 min to obtain a pre-treated body.

[0051] S2. Load the pretreated body into a steel mold with a sealed cover, evacuate to 94 kPa, inject the composite sol, and impregnate for 120 min. Here, the composite sol is 45 parts by mass of acid silica sol + 8 parts by mass of ZrO2 sol, with a viscosity of 12 mPa·s.

[0052] S3. Keep the sol liquid level submerging the top of the pretreated body, connect the compressed air system to apply a pulsating pressure of 0.5 MPa, and operate in a cycle of pressurization for 30 s / depressurization for 60 s. Continuously dry at 50 °C for 900 min to form a blank. After drying, cut off the 50 mm area at the bottom of the blank.

[0053] S41. Immerse the blank in 45% acid silica sol under 100 kPa vacuum for 120 min, and after taking it out, dry at 200 °C for 150 min; S42. Immerse it again in 30% acid silica sol under 100 kPa vacuum for 120 min; S43. Place it in an electric furnace and sinter at 800 °C for 300 min, and keep the temperature for 200 min to obtain a high-strength and high-density quartz fiber-reinforced quartz composite material.

[0054] Comparative Example 1 This comparative example provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material. The difference from Example 1 is that: The pulsating pressure field is cancelled, and the sol is discharged manually in stages: lower the liquid level by 200 mm every 180 min (a total of 4 discharges), and the other steps are the same as those in Example 1.

[0055] Comparative Example 2 This comparative example provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material. The difference from Example 1 is that: The composite sol only contains 42.5 parts by mass of acid silica sol (without ZrO2 sol), and the other steps are the same as those in Example 1.

[0056] Comparative Example 3 This comparative example provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material. The difference from Example 1 is that: The pulsating pressure field is changed to a constant pressure of 0.35 MPa, that is, the pressurization / depressurization cycle is cancelled, and the other steps are the same as those in Example 1.

[0057] Comparative Example 4 This comparative example provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material. The difference from Example 1 is that: In S3, the bottom area of the blank is not cut off, and the other steps are the same as those in Example 1.

[0058] Comparative Example 5 This comparative example provides a method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite, which is different from Example 1 in that: S41 and S42 use sols with the same concentration (both 42.5% acid silica sol), and the other steps are the same as those in Example 1.

[0059] Test the properties of the high-strength and high-density quartz fiber-reinforced quartz composites prepared by the methods provided in the above examples and comparative examples. The test method is as follows: 1. Density uniformity: Measurement method: Cut the finished product into 5 specimens (top / middle upper / middle / middle lower / bottom) at equal intervals along the height direction, and the cutting cross-section of each specimen is 20×20 mm 3 , then boil the specimens in water for 2 h and immerse them in room-temperature deionized water for 24 h until constant weight, and weigh the wet weight of the saturated water specimens with an electronic balance with an accuracy of 0.1 mg W w Dry the specimens at 105 °C until constant weight and weigh the dry weight W d Then calculate its apparent density according to the following formula: , where, W s For Weight of the specimen suspended in water, ρ water Take 1 g / cm 3 ; Then, according to the apparent densities of the 5 specimens ρ , calculate the average density ; Calculate the standard deviation of the 5 specimens according to the following formula σ : , where, ρ i is the density of a single specimen; and the density deviation rate δ : , where, ρ top is the density of the topmost specimen, ρ bottom is the density of the bottommost specimen.

[0060] 2. Penetration depth: Measurement method: After the drying in S3 is completed, cut the cross-section along the height direction of the blank, spray 0.1% methylene blue solution for staining for 30 s, and measure the height of the blue area (sol penetration area) after rinsing with clear water.

[0061] 3. Bubble defect density: Measurement method: Polish the cross-section of the finished product and count the number of bubbles (diameter > 50 μm) within a 1 cm 2 area under a 20x magnifying glass.

[0062]

[0063] Analysis of experimental results In Example 1, the standard deviation of density is 0.0085 g / cm 3 indicating a high degree of uniformity inside the material. A density deviation rate of 0.56% means there is almost no attenuation in the 1000 mm height direction; the penetration depth of 1000 mm is fully filled, and there are only 3 bubbles / cm 2 verifying the process stability.

[0064] In Example 2, the standard deviation of density is 0.0092 g / cm 3 and the penetration depth of 980 mm is slightly lower than that in Example 1, but the deviation rate of 0.62% and 4 bubbles / cm 2 still meet the requirements of high uniformity.

[0065] In Example 3, the penetration depth is 1500 mm, and the low standard deviation of 0.0078 g / cm 3 and the deviation rate of 0.51% show the adaptability of the optimized parameters to super-large components. There are 2 bubbles / cm 2 which is the best in the whole group.

[0066] In Comparative Example 1, the bubble defects increase to 18 bubbles / cm 2 (500% higher than that in Example 1), and the standard deviation is 0.032 g / cm 3 indicating that multiple mold openings introduce structural disturbances, and although the penetration depth reaches 1000 mm, the uniformity deteriorates severely.

[0067] In Comparative Example 2, due to the lack of zirconia, the wettability of the sol is insufficient, the top is fully filled while the bottom is significantly under-filled, and the penetration depth is only 720 mm. However, due to no bubble interference, the density within the same height layer is relatively uniform. The deviation rate of 3.2% indicates a significant density attenuation in the height direction, proving the key role of zirconia in the longitudinal migration of the sol. In Comparative Example 1, due to manual discharge, the sol filling is discontinuous, and the bubbles are randomly distributed. The random bubbles cause local severe fluctuations, and σ is higher than that in Comparative Example 2.

[0068] In Comparative Example 3, the penetration depth is insufficient at 800 mm and there are 15 bubbles / cm 2 , indicating the necessity of periodic pressure changes for gas discharge and complete penetration.

[0069] In Comparative Example 4, the standard deviation is 0.021 g / cm3 It is 2.5 times that of Example 1, and the deviation rate of 1.9% confirms the negative impact of the bottom settlement area on the overall uniformity.

[0070] In Comparative Example 5, the standard deviation is 0.019 g / cm 3 significantly increases, indicating that a single concentration cannot balance macropore filling and micropore penetration, resulting in a decrease in the matrix density.

[0071] In summary, the pulsating pressure field (0.2 - 0.5 MPa) combined with the zirconia-modified sol (3 - 8 parts by mass) can stably achieve complete penetration of components with a height of 500 - 1500 mm (penetration depth = component height), and the density standard deviation ≤ 0.0092 g / cm 3 ; cutting 20 - 50 mm at the bottom compensates for the gravity settlement effect, making the density deviation rate in the height direction ≤ 0.62%; the staged concentration impregnation (40 - 45% → 20 - 30%) controls the bubble defects within ≤ 4 pieces / cm 2 , and the efficiency of the whole process is 24 times higher than that of the manual discharge process.

[0072] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a high-strength and high-density quartz fiber-reinforced quartz composite material, characterized in that, Including: S1. Heat-treat the quartz fiber preform at 400 - 600 °C for 130 - 240 min to obtain a pre-treated body; S2. Place the pre-treated body in a mold, evacuate to a vacuum degree < 96 kPa, and then inject a composite sol, and impregnate for 60 - 120 min; S3. Keep the liquid level of the composite sol submerging the top of the pre-treated body, apply a pulsating pressure field of 0.2 - 0.5 MPa, and dry at 30 - 50 °C for 450 - 900 min to form a blank; S4. Conduct densification treatment and sintering treatment on the blank in sequence.

2. The method according to claim 1, characterized in that, In S3, the pressure change period of the pulsating pressure field is 30 s for pressure increase / 60 s for pressure decrease.

3. The method according to claim 1 or 2, characterized in that: The composite sol includes: Acid silica sol 40 - 45 parts by mass, ZrO2 sol 3 - 8 parts by mass, and the viscosity of the composite sol < 15 mPa·s.

4. The method according to claim 1, wherein The pressure range of the pulsating pressure field is 0.3 - 0.4 MPa.

5. The method according to claim 3, characterized in that: The addition amount of the ZrO2 sol is 5 - 7 parts by mass.

6. The method according to claim 1, characterized in that, After the drying in S3 is completed, cut off the 20 - 50 mm area at the bottom of the blank.

7. The method according to claim 1, characterized in that, The height of the quartz fiber preform is 500 - 1500 mm, and the thickness is 6 - 30 mm.

8. The method according to claim 1, wherein The specific steps of S4 include: S41. Vacuum-impregnate the blank in 40 - 45% acid silica sol for 60 - 120 min, and dry at 150 - 200 °C for 100 - 150 min; S42. Vacuum-impregnate the blank in 20 - 30% acid silica sol for 60 - 120 min; S43. Sinter at 700 - 800 °C for 200 - 300 min.

9. The method according to claim 8, characterized in that, The vacuum degree in both S41 and S42 is 100 kPa.

10. The method according to claim 8, characterized in that, In S43, after the sintering, it also includes heat preservation, and the heat preservation duration is 150 - 200 min.

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