An antioxidant ablation-resistant short-cut oxide fiber preform and a forming preparation method thereof

Abstract

This invention relates to an antioxidant and ablation-resistant chopped oxide fiber preform and its molding preparation method, belonging to the technical field of heat insulation materials. The molding preparation method of the antioxidant and ablation-resistant chopped oxide fiber preform includes: mixing chopped oxide fibers, multi-component ceramic components, binder, adsorbent, water-soluble viscosity modifier, and water; heating and stirring to obtain a slurry; washing the slurry with alcohol and filtering by pressure to obtain a wet preform; and drying, curing, and carbonizing the wet preform to obtain the antioxidant and ablation-resistant chopped oxide fiber preform. The molding preparation method of the antioxidant and ablation-resistant chopped oxide fiber preform provided by this invention can overcome the density differences of raw materials, enabling the uniform introduction of medium-density ceramic particles and low-density hollow ceramic microspheres into the interior of a high-density chopped oxide fiber preform, resulting in a lightweight antioxidant and ablation-resistant chopped oxide fiber preform with excellent performance.

Description

Technical Field

[0001] This invention relates to the field of heat insulation materials technology, and in particular to an antioxidant and ablation-resistant short-cut oxide fiber preform and its molding and preparation method. Background Technology

[0002] Oxide fiber preforms are fibrous network structures formed by bonding adjacent short-cut oxide fibers at their intersections. They are characterized by low density, high porosity (with interconnected pores), low thermal conductivity, good high-temperature dimensional stability and chemical stability, making them suitable as reinforcing phases for manufacturing thermal insulation and ablation materials. They have important applications in the military, defense, aviation and aerospace industries.

[0003] Because oxide fibers, such as alumina and silicon oxide fibers, are generally polycrystalline or amorphous materials, their thermodynamically unstable crystal forms tend to transform into high-temperature stable crystal forms during temperature fluctuations. This results in significant volume effects, leading to fiber creep and embrittlement, making it difficult to maintain the mechanical properties of the composite material and severely limiting its long-term use at high temperatures (not lower than 1000℃). To address the high-temperature failure behavior of oxide fiber materials and improve their adaptability to extreme environments, it is necessary to modify the composition and structure of oxide fiber preforms.

[0004] From an engineering application perspective, the most direct and effective method for preparing ablation-resistant oxide fiber preforms is slurry modification. This involves mixing ceramic components (fibers, powders, etc.) with chopped oxide fibers to form an aqueous slurry, which is then filtered, dried, and cured to form a porous preform. However, oxide fibers have a high density, while ceramic powders have a low density. During slurry preparation, stratification and sedimentation easily occur, resulting in the ceramic components not being uniformly dispersed within the fiber preform. Consequently, the modified fiber preform tends to have poor uniformity, high density, and poor mechanical strength and high-temperature service capability. Summary of the Invention

[0005] To address one or more technical problems existing in the prior art, the present invention provides an antioxidant and ablation-resistant chopped oxide fiber preform and its molding preparation method. The molding preparation method of the antioxidant and ablation-resistant chopped oxide fiber preform provided by the present invention can overcome the difference in raw material density and realize the uniform introduction of medium-density ceramic particles and low-density hollow ceramic microspheres into the interior of high-density chopped oxide fiber preform, thereby obtaining a lightweight antioxidant and ablation-resistant chopped oxide fiber preform with excellent performance.

[0006] This invention provides a method for molding and preparing an antioxidant and ablation-resistant chopped oxide fiber preform, characterized in that the preparation method includes:

[0007] Short-cut oxide fibers, multi-component ceramic components, binder, adsorbent, water-soluble viscosity modifier and water are mixed and heated and stirred to obtain a slurry;

[0008] The slurry was washed with alcohol and then filtered to obtain a wet preform.

[0009] The wet preform is dried, cured, and carbonized to obtain an antioxidant and ablation-resistant short-cut oxide fiber preform.

[0010] Preferably, the amount of the ceramic component is 30-50% of the mass of the chopped oxide fibers;

[0011] The amount of the adhesive is 30-65% of the mass of the chopped oxide fibers; and / or

[0012] The amount of water used is 30 to 40 times the total mass of the chopped oxide fibers, binder, and ceramic components.

[0013] Preferably, the chopped oxide fiber is at least one of chopped alumina fiber, chopped silica fiber, chopped mullite fiber, and chopped zirconium oxide fiber;

[0014] The length of the chopped oxide fibers is 1–3 mm;

[0015] The multi-component ceramic component comprises at least two of the following: hollow silica microspheres, silicon carbide powder, and zirconium boride powder; and / or

[0016] The binder includes phenolic resin, starch, and glass fiber powder;

[0017] Preferably, the amount of phenolic resin used is 20-40% of the mass of the chopped oxide fibers;

[0018] The amount of starch used is 10-20% of the mass of the chopped oxide fiber; and / or

[0019] The amount of glass fiber powder used is 20-30% of the mass of the chopped oxide fibers.

[0020] Preferably, the amount of adsorbent used is 0.5% to 1% of the water mass; more preferably, the adsorbent is polyethyleneimine.

[0021] Preferably, the amount of the water-soluble viscosity modifier is 0.1-0.25% of the water mass; more preferably, the water-soluble viscosity modifier is one or more of polyacrylamide, gelatin, guar gum, and carrageenan.

[0022] Preferably, the heating and stirring temperature is 40–70°C, and the time is 1–2 hours.

[0023] Preferably, the amount of alcohol used in the alcohol washing process is 1.5 to 3 times the mass of water in the slurry; and / or

[0024] The pressure for the filter press is 50–200 kPa, and the time is 1–2 h.

[0025] Preferably, the drying temperature is 60–80°C and the drying time is 24–72 hours;

[0026] The curing temperature is 150–200°C, and the time is 2–4 hours; and / or

[0027] The carbonization temperature is 500–800℃, and the time is 2–4 hours.

[0028] In a second aspect, the present invention provides an ablation-resistant quartz fiber skeleton, which is prepared by the preparation method described in the first aspect.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] This invention introduces an adsorbent into the slurry to impart a positive charge to the surface of chopped oxide fibers, thereby adsorbing the negatively charged binder and ceramic components onto the surface and surrounding area of ​​the fibers. Furthermore, the addition of a water-soluble viscosity modifier creates a large gel-like network between the chopped oxide fibers, increasing the viscosity of the aqueous slurry. This better stabilizes the binder and ceramic powder around the fibers, promoting uniform adsorption of the binder and ceramic components on the surface and at the joints of the fibers. Simultaneously, the gel network formed by the water-soluble viscosity modifier encapsulates other components, resulting in a slurry with uniform structure and composition. This effectively solves the problem of existing slurry methods where the density difference between oxide fibers and ceramic components easily leads to stratification and sedimentation, preventing the production of a uniform slurry.

[0031] This invention overcomes the density differences of raw materials by combining the action of adsorbents and water-soluble viscosity modifiers. Medium and low density ceramic components are blended with high density short-cut oxide fibers to obtain a fiber slurry with relatively uniform composition. During the alcohol washing process, the gel network formed by the water-soluble viscosity modifier, which is not easily soluble in alcohol, encapsulates other components and causes them to detach and settle from the slurry, resulting in a co-precipitate containing short-cut oxide fibers, multi-component ceramic components, and a binder. The co-precipitate is then filtered by pressure to achieve solid-liquid separation, resulting in a wet preform with uniformly distributed components. Finally, after drying, curing, and carbonization, an oxidation-resistant and ablation-resistant short-cut oxide fiber preform with uniformly distributed multi-component ceramic components is obtained.

[0032] The molding and preparation method of the antioxidant and ablation-resistant chopped oxide fiber preform of the present invention can overcome the difference in raw material density and realize the uniform introduction of medium-density ceramic particles and low-density hollow ceramic microspheres into the interior of high-density chopped oxide fiber preform, so as to obtain a lightweight antioxidant and ablation-resistant chopped oxide fiber preform with excellent performance. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a comparison diagram of the slurry before and after alcohol washing in Example 6 of the present invention;

[0035] Figure 2 This is a physical image of the slurry in Comparative Example 1 of the present invention;

[0036] Figure 3 This is a microscopic image of the antioxidant and ablation-resistant chopped oxide fiber preform provided in Comparative Example 2 of the present invention;

[0037] Figure 4 This is a microscopic image of the antioxidant and ablation-resistant chopped oxide fiber preform provided in Comparative Example 8 of the present invention;

[0038] Figure 5 These are macroscopic and microscopic images of the antioxidant and ablation-resistant chopped oxide fiber preform provided in Embodiment 4 of the present invention;

[0039] Figure 6 These are macroscopic and microscopic images of the antioxidant and ablation-resistant chopped oxide fiber preform provided in Embodiment 5 of the present invention;

[0040] Figure 7 These are macroscopic and microscopic images of the antioxidant and ablation-resistant chopped oxide fiber preform provided in Embodiment 6 of the present invention;

[0041] Figure 8 These are macroscopic morphology images of the antioxidant and ablation-resistant short-cut oxide fiber preforms provided in Examples 4-6 and Comparative Example 10 of this invention after butane thermal testing (testing conditions: treatment at 1100℃ for 1800s). Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0043] This invention provides a method for molding and preparing an antioxidant and ablation-resistant chopped oxide fiber preform, characterized in that the preparation method includes:

[0044] Short-cut oxide fibers, multi-component ceramic components, binder, adsorbent, water-soluble viscosity modifier and water are mixed and heated and stirred to obtain a slurry;

[0045] The slurry was washed with alcohol and then filtered to obtain a wet preform.

[0046] The wet preform is dried, cured, and carbonized to obtain an antioxidant and ablation-resistant short-cut oxide fiber preform.

[0047] This invention introduces an adsorbent into the slurry to impart a positive charge to the surface of chopped oxide fibers, thereby adsorbing the negatively charged binder and ceramic components onto the surface and surrounding area of ​​the fibers. Furthermore, the addition of a water-soluble viscosity modifier creates a large gel-like network between the chopped oxide fibers, increasing the viscosity of the aqueous slurry. This better stabilizes the binder and ceramic powder around the fibers, promoting uniform adsorption of the binder and ceramic components on the surface and at the joints of the fibers. Simultaneously, the gel network formed by the water-soluble viscosity modifier encapsulates other components, resulting in a slurry with uniform structure and composition. This effectively solves the problem of existing slurry methods where the density difference between oxide fibers and ceramic components easily leads to stratification and sedimentation, preventing the production of a uniform slurry.

[0048] This invention overcomes the density differences of raw materials by combining the action of adsorbents and water-soluble viscosity modifiers. Medium and low density ceramic components are blended with high density short-cut oxide fibers to obtain a fiber slurry with relatively uniform composition. During the alcohol washing process, the gel network formed by the water-soluble viscosity modifier, which is not easily soluble in alcohol, encapsulates other components and causes them to detach and settle from the slurry, resulting in a co-precipitate containing short-cut oxide fibers, multi-component ceramic components, and a binder. The co-precipitate is then filtered by pressure to achieve solid-liquid separation, resulting in a wet preform with uniformly distributed components. Finally, after drying, curing, and carbonization, an oxidation-resistant and ablation-resistant short-cut oxide fiber preform with uniformly distributed multi-component ceramic components is obtained.

[0049] The molding and preparation method of the antioxidant and ablation-resistant chopped oxide fiber preform of the present invention can overcome the difference in raw material density and realize the uniform introduction of medium-density ceramic particles and low-density hollow ceramic microspheres into the interior of high-density chopped oxide fiber preform, so as to obtain a lightweight antioxidant and ablation-resistant chopped oxide fiber preform with excellent performance.

[0050] According to some preferred embodiments, the amount of the ceramic component is 30-50% of the mass of the chopped oxide fibers;

[0051] The amount of the adhesive is 30-65% of the mass of the chopped oxide fibers; and / or

[0052] The amount of water used is 30 to 40 times the total mass of the chopped oxide fibers, binder, and ceramic components.

[0053] According to some preferred embodiments, the chopped oxide fiber is at least one of chopped alumina fiber, chopped silica fiber, chopped mullite fiber, and chopped zirconia fiber.

[0054] According to some preferred embodiments, the length of the chopped oxide fiber is 1 to 3 mm.

[0055] According to some preferred embodiments, the multi-element ceramic component comprises at least two of the following: silicon oxide hollow microspheres, silicon carbide powder, and zirconium boride powder. This invention achieves uniform coating of ceramic powder on the surface of the oxide fiber preform and at the fiber overlap points by introducing ceramic powder and hollow ceramic microspheres into the slurry. The gaps between the fibers are filled with lightweight, high-strength hollow microspheres, and both are uniformly distributed within the oxide fiber preform, synergistically improving the material's ablation resistance.

[0056] According to some preferred embodiments, the binder includes phenolic resin, starch, and glass fiber powder. This invention, through the combined use of multiple binders including starch, phenolic resin, and glass fiber powder, ensures that the material maintains a good fibrous network structure from slurry extraction to high-temperature service, thereby obtaining an antioxidant and ablation-resistant chopped oxide fiber preform with excellent performance. The phenolic resin accounts for 20-40% of the weight of the chopped oxide fiber and is an important binder in both the dry (after drying) and finished product states, providing a binding effect at 80-1000℃; the glass fiber powder accounts for 20-30% of the weight of the chopped oxide fiber and is an important binder during the thermal testing process, providing a binding effect at 600-1200℃; the starch accounts for 10-20% of the weight of the chopped oxide fiber and, in combination with the water-soluble viscosity modifier polyacrylamide, is an important binder in both the slurry and wet preform states, providing a binding effect at 20-200℃.

[0057] According to some preferred embodiments, the amount of phenolic resin used is 20-40% of the mass of the chopped oxide fibers.

[0058] According to some preferred embodiments, the amount of starch used is 10-20% of the mass of the chopped oxide fiber.

[0059] According to some preferred embodiments, the amount of glass fiber powder used is 20-30% of the mass of the chopped oxide fibers.

[0060] According to some preferred embodiments, the amount of adsorbent used is 0.5% to 1% of the water mass; preferably, the adsorbent is polyethyleneimine.

[0061] According to some preferred embodiments, the amount of the water-soluble viscosity modifier is 0.1-0.25% of the water mass; preferably, the water-soluble viscosity modifier is one or more of polyacrylamide, gelatin, guar gum, and carrageenan, and more preferably one or more of nonionic polyacrylamide, cationic polyacrylamide, and anionic polyacrylamide.

[0062] According to some preferred embodiments, the heating and stirring temperature is 40–70°C, and the time is 1–2 hours. This invention mixes chopped oxide fibers, multi-component ceramic components, a binder, an adsorbent, a water-soluble viscosity modifier, and water. By controlling the amount of each component and heating and stirring, the dispersibility of the multi-component ceramic components and binder on the surface and between the chopped oxide fibers is improved, resulting in a slurry with relatively uniform structure and composition.

[0063] According to some preferred embodiments, the amount of alcohol used in the alcohol washing process is 1.5 to 3 times the mass of water in the slurry. This invention uses an alcohol washing process to allow a gel network formed by a water-soluble viscosity modifier to encapsulate other components, causing them to precipitate from the slurry and resulting in a co-precipitate with uniformly dispersed components. The purpose of alcohol washing is to precipitate substances insoluble in alcohol, achieving solid-liquid separation of the slurry; alcohol is more volatile than water, requiring a lower drying temperature; alcohol has low surface tension, resulting in less shrinkage of short-cut fiber products during drying. Solid-liquid separation can be achieved when the amount of alcohol is 1.5 to 3 times the amount of water in the slurry; if the amount of alcohol is too small, it dissolves in water, and polyacrylamide cannot precipitate; if the amount of alcohol is too large, it is wasteful. The inventors discovered that without alcohol washing, a viscous slurry is obtained, and after pressure filtration, the slurry shows no significant change, making solid-liquid separation impossible.

[0064] According to some preferred embodiments, the pressure of the filter press is 50-200 kPa and the time is 1-2 h.

[0065] According to some preferred embodiments, the drying temperature is 60-80°C and the time is 24-72 hours.

[0066] According to some preferred embodiments, the curing temperature is 150-200°C and the time is 2-4 hours.

[0067] According to some preferred embodiments, the carbonization temperature is 500–800°C and the time is 2–4 hours.

[0068] It should be noted that phenolic resin is an alcohol-soluble substance, and a small amount of it will be lost during the alcohol washing process, but this will not affect its overall curing and adsorption effects. During the drying process, while most of the solvent is removed, the phenolic resin is partially cured by heat, thus playing a bonding role. During the curing process, the phenolic resin is completely cured and strengthens the bonded block. During the carbonization process, small molecules and unstable groups in the framework are removed by the reaction.

[0069] In a second aspect, the present invention provides an antioxidant and ablation-resistant short-cut oxide fiber preform, which is prepared by the preparation method described in the first aspect.

[0070] The antioxidant and ablation-resistant chopped oxide fiber preform provided by this invention has ceramic components evenly distributed on the surface, at the fiber overlap points, and in the fiber gaps. This can improve the temperature resistance of the fiber skeleton, maintain a good fibrous network structure at high temperatures, and has excellent ablation resistance.

[0071] The density of the antioxidant and ablation-resistant chopped oxide fiber preform provided by this invention does not exceed 0.5 g / cm³. 3 The room temperature Z-axis compressive strength can reach 1.6 MPa, and the room temperature Z-axis thermal conductivity does not exceed 0.049 W·m. -1 ·K -1 After 900 seconds in a muffle furnace at 1000℃, the compressive strength retention rate was over 60%, and after 1800 seconds of butane ablation at 1100℃, the linear ablation rate was as low as 3.61 × 10⁻⁶. - 3 mm·s -1 The mass ablation rate can be as low as 2.41 × 10⁻⁶. -3 g·s -1 .

[0072] To more clearly illustrate the technical solution and advantages of the present invention, the present invention will be further described below with reference to embodiments. The present invention does not specifically limit the source of the reagents used in the embodiments and comparative examples; they can be directly purchased or synthesized in-house.

[0073] Example 1

[0074] (1) Mix polyethyleneimine with deionized water and stir thoroughly to obtain a polyethyleneimine aqueous solution, i.e., solution A; mix nonionic polyacrylamide with deionized water and heat and stir in a water bath at 60°C to obtain a polyacrylamide aqueous solution, i.e., solution B; then add chopped alumina fiber, phenolic resin powder, starch, glass fiber powder, zirconium boride powder, and silicon carbide powder to solution A in sequence, stir evenly, and then add an appropriate amount of solution B to obtain a mixture. Under the stirring action of stirring at a stirring speed of 300 r / min, heat in a water bath at 60°C and keep warm for 1 h to obtain a slurry; wherein, the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, starch, phenolic resin powder, glass fiber powder, zirconium boride powder, and silicon carbide powder is 700:5:1:10:1:3:2:1:2.

[0075] (2) The obtained slurry is mixed with ethanol (the amount of ethanol is twice the mass of deionized water in the slurry) and stirred at a stirring speed of 150 r / min for 30 min. The precipitated blend is taken out, transferred into a filter press mold, pressurized to 100 kPa and held for 2 h to obtain a wet blank.

[0076] (3) Place the sealed mold containing the wet blank into a 70℃ oven and dry it for 40 hours, and then demold it to obtain a dry blank; cure the obtained dry blank by heating it to 150℃ at a heating rate of 5℃ / min for 3 hours. After curing, a multi-element ceramic modified alumina fiber preform is obtained; place the above multi-element ceramic modified alumina fiber preform in an argon atmosphere for carbonization by heating it to 800℃ at a heating rate of 5℃ / min for 3 hours to obtain an oxidation-resistant and ablation-resistant short-cut oxide fiber preform.

[0077] Embodiments 2-6 of the present invention are basically the same as Embodiment 1, with the differences shown in Table 1 below.

[0078] Table 1. Comparison of parameters in the preparation process of Examples 1-6 of the present invention

[0079]

[0080] Note: The amount of ethanol used in the table is a multiple of the mass of ethanol to the mass of deionized water in the slurry.

[0081] Depend on Figure 1 It can be seen that the components in the slurry obtained after dispersion in Example 6 are uniformly dispersed, and a co-precipitate with uniformly dispersed components can be formed after alcohol washing. It should be noted that Examples 2-6 of the present invention can all obtain... Figure 1 Slurries and coprecipitates with similar morphologies will not be described in detail here.

[0082] Comparative Example 1

[0083] It is basically the same as Example 6, except that: polyethyleneimine and nonionic polyacrylamide were not added.

[0084] like Figure 2 As shown, due to the absence of polyethyleneimine and nonionic polyacrylamide, the ceramic components and fibers were severely separated during the dispersion process. The top layer of floating matter consisted of hollow silica microspheres, while the bottom layer of precipitate consisted of chopped alumina fibers and chopped silica fibers. Alcohol washing could not form coprecipitates.

[0085] Comparative Example 2

[0086] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:1:2.5:12:8:6:2:3:3:3:2.

[0087] like Figure 3 As shown, in this comparative example, the adsorption effect of the ceramic component was poor and the modification effect was not obvious due to the insufficient amount of polyethyleneimine. Electron microscopy images revealed that only a very small amount of ceramic component was adsorbed on the fiber surface and at the fiber overlaps in the final fiber preform, and the ceramic component exhibited agglomeration.

[0088] Comparative Example 3

[0089] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:0.5:12:8:6:2:3:3:3:2.

[0090] In this comparative example, due to insufficient use of nonionic polyacrylamide, although the ceramic components and fibers did not show obvious agglomeration during the dispersion process, the slurry separated into layers, and alcohol washing could not form coprecipitates.

[0091] Comparative Example 4

[0092] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:5:12:8:6:2:3:3:3:2.

[0093] In this comparative example, due to excessive use of nonionic polyacrylamide, multiple "dough-like" flocs were formed during the alcohol washing process, resulting in uneven distribution of ceramics and fibers; the shape was difficult to control during the curing process.

[0094] Comparative Example 5

[0095] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:2.5:12:8:6:0:3:3:3:2.

[0096] Because the slurry formed in this comparative example did not contain starch, its integrity was poor after alcohol washing, resulting in significant loss of ceramic components during the pressure filtration process.

[0097] Comparative Example 6

[0098] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:2.5:12:8:6:5:3:3:3:2.

[0099] In this comparative example, due to the excessive amount of starch added, uncontrolled sedimentation of each component occurred during the slurry preparation process, resulting in poor dispersion uniformity of each component in the slurry. Although co-precipitates could be formed after alcohol washing, only a very small amount of ceramic components were adsorbed on the fiber surface and fiber overlap. That is, most of the ceramic components and fibers settled separately, and the components were not evenly distributed.

[0100] Comparative Example 7

[0101] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:2.5:12:8:2:2:3:3:3:2.

[0102] In this comparative example, due to insufficient phenolic resin content, insufficient adhesion occurred after curing, resulting in powdering and easy structural damage.

[0103] Comparative Example 8

[0104] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:10:2.5:12:8:10:2:3:3:3:2.

[0105] In this comparative example, due to the excessive amount of phenolic resin, the adhesion was excessive, resulting in excessive density and hardening after curing. For example... Figure 4 As shown, only a very small amount of ceramic components are adsorbed on the fiber surface and fiber overlap in the final fiber preform, while a large amount of phenolic resin is adsorbed on the fiber surface and fiber overlap, blocking the pores and affecting the thermal insulation performance.

[0106] Comparative Example 9

[0107] The method is basically the same as Example 6, except that the mass ratio of deionized water, polyethyleneimine, nonionic polyacrylamide, chopped alumina fiber, chopped silica fiber, phenolic resin, starch, glass fiber powder, zirconium boride, silicon carbide, and silica hollow microspheres is 1500:0.23:0.31:12:8:6:2:3:3:3:2.

[0108] In this comparative example, due to the insufficient dosage of both polyethyleneimine and nonionic polyacrylamide, the ceramic components and fibers in the resulting slurry agglomerated, and the slurry separated into layers; alcohol washing failed to form coprecipitates.

[0109] Comparative Example 10

[0110] It is basically the same as Example 6, except that no ceramic components (zirconium boride, silicon carbide and silicon oxide hollow microspheres) were added.

[0111] Comparative Example 11

[0112] It is basically the same as Example 6, except that: alcohol washing was not performed, and the slurry from step (1) was directly pressure filtered.

[0113] Step (1) yields a viscous slurry. After pressure filtration, the slurry shows no significant change and solid-liquid separation cannot be achieved.

[0114] like Figure 5 As shown, in the oxidation-resistant and ablation-resistant chopped oxide fiber preform prepared in Example 4, the overlaps of the chopped alumina fibers, represented by aluminum (Al), are effectively bonded together by phenolic resin, represented by carbon (C), and glass fiber powder, represented by silicon (Si), exhibiting a dotted bond of approximately 100 μm. The surface and overlaps of the alumina fibers are filled with silicon carbide powder, represented by silicon (Si), and zirconium boride powder, represented by zirconium (Zr), with a distribution scale not exceeding 50 μm.

[0115] like Figure 6As shown, in the oxidation-resistant and ablation-resistant chopped oxide fiber preform prepared in Example 5, the overlaps of the chopped alumina fibers, represented by aluminum (Al), are effectively bonded together by phenolic resin, represented by carbon (C), and glass fiber powder, represented by silicon (Si), exhibiting a dotted bond of approximately 100 μm. The surface and overlaps of the alumina fibers are filled with silicon carbide powder, represented by silicon (Si), hollow silica microspheres, and zirconium boride powder, represented by zirconium (Zr), with a distribution scale not exceeding 50 μm.

[0116] like Figure 7 As shown, in the oxidation-resistant and ablation-resistant chopped oxide fiber preform prepared in Example 6, the overlaps of chopped alumina fibers (represented by aluminum (Al)) and chopped silica fibers (represented by silicon (Si)) are effectively bonded by phenolic resin (represented by carbon (C)) and glass fiber powder (represented by silicon (Si)), exhibiting a dotted bond of approximately 100 μm. The surfaces and overlaps of the alumina and silica fibers are filled with silicon carbide powder (represented by silicon (Si), silica hollow microspheres, and zirconium boride powder (represented by zirconium (Zr)), with a distribution scale not exceeding 50 μm.

[0117] Depend on Figure 8 It can be seen that the oxidation-resistant and ablation-resistant chopped oxide fiber preforms (all with dimensions of 80mm (length) × 80mm (width) × 20mm (height)) prepared in Examples 4-6 of this invention have smooth surfaces and no large-area pulverization after butane thermal testing, indicating that the addition of ceramic components significantly improves the shape retention and heat resistance of the fiber skeleton at high temperatures. In contrast, the oxidation-resistant and ablation-resistant chopped oxide fiber preform of Comparative Example 10 decomposed and pulverized layer by layer during the testing process, with large-area surface damage, indicating that oxide fiber preforms without the introduction of ceramic components have difficulty resisting thermal erosion and maintaining structural integrity and performance stability.

[0118] The performance data of the antioxidant and ablation-resistant chopped oxide fiber preforms of the present invention are shown in Table 2. The test methods for each performance data are all general test methods in the art.

[0119] Table 2. Performance data of the antioxidant and ablation-resistant chopped oxide fiber preforms of the present invention.

[0120]

[0121]

[0122] It should be noted that the test conditions for the linear ablation rate and mass ablation rate in the table are 1100℃ for 1800s, and the compressive strength retention rate is obtained after 1000℃ for 900s.

[0123] As can be seen from Table 1, the density of the antioxidant and ablation-resistant chopped oxide fiber preform provided in the embodiments of the present invention does not exceed 0.50 g / cm³. 3 The room temperature Z-axis compressive strength can reach 1.6 MPa, and the room temperature Z-axis thermal conductivity does not exceed 0.049 W·m. -1 ·K -1 After 900 seconds in a muffle furnace at 1000℃, the compressive strength retention rate was over 60%, and after 1800 seconds of butane ablation at 1100℃, the linear ablation rate was as low as 3.61 × 10⁻⁶. -3 mm·s -1 The mass ablation rate can be as low as 2.41 × 10⁻⁶. -3 g·s -1 .

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for molding and preparing an antioxidant and ablation-resistant chopped oxide fiber preform, characterized in that, The preparation method comprises the following steps: The short-cut oxide fiber, the multi-element ceramic component, the binder, the adsorbent, the water-soluble viscosity regulator and water are mixed, and heated and stirred to obtain a slurry; the amount of the multi-element ceramic component is 30-50% of the mass of the short-cut oxide fiber; the multi-element ceramic component is ceramic powder and / or ceramic hollow microspheres; the amount of the binder is 30-65% of the mass of the short-cut oxide fiber; and the amount of water is 30-40 times of the total mass of the short-cut oxide fiber, the binder and the multi-element ceramic component. The binder comprises phenolic resin, starch and glass fiber powder; the amount of the phenolic resin is 20-40% of the mass of the short-cut oxide fiber; the amount of the starch is 10-20% of the mass of the short-cut oxide fiber; and the amount of the glass fiber powder is 20-30% of the mass of the short-cut oxide fiber. The amount of the adsorbent is 0.5-1% of the mass of water; and the adsorbent is polyethylene imine. The amount of the water-soluble viscosity regulator is 0.1-0.25% of the mass of water; and the water-soluble viscosity regulator is one or more of polyacrylamide, gelatin, guar gum and carrageenan. The slurry is subjected to alcohol washing and pressure filtration to obtain a wet blank; the amount of alcohol used in the alcohol washing process is 1.5-3 times of the mass of water in the slurry. The wet blank is dried, solidified and carbonized to obtain an antioxidant and ablation-resistant short-cut oxide fiber preform.

2. The production method according to claim 1, characterized by, The short-cut oxide fiber is at least one of short-cut alumina fiber, short-cut silica fiber, short-cut mullite fiber and short-cut zirconia fiber. The length of the short-cut oxide fiber is 1-3 mm. The multi-element ceramic component is at least two of silica hollow microspheres, silicon carbide powder and zirconium boride powder.

3. The method of claim 1, wherein, The temperature of the heating and stirring is 40-70 ℃, and the time is 1-2 h.

4. The method of claim 1, wherein, The pressure of the pressure filtration is 50-200 kPa, and the time is 1-2 h.

5. The preparation method according to claim 1, characterized in that, The temperature of the drying is 60-80 ℃, and the time is 24-72 h. The temperature of the solidification is 150-200 ℃, and the time is 2-4 h.

6. The method of claim 1, wherein, The temperature of the carbonization is 500-800 ℃, and the time is 2-4 h.

7. An ablation-resistant quartz fiber skeleton, characterized by, The preparation method is prepared by any one of claims 1-6.

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