Boron phenolic aerogel multi-dimensional framework composite material for additive manufacturing and preparation method of boron phenolic aerogel multi-dimensional framework composite material

Abstract

The invention belongs to the technical field of high-temperature heat-proof composite materials, and particularly relates to a boron phenolic aerogel multi-dimensional framework composite material for additive manufacturing and a preparation method thereof. Comprising the following steps: synthesizing boron-containing phenolic resin by a sol-gel method, preparing a high-porosity ZrB2 ceramic skeleton by combining a photocuring 3D printing technology, filling pores of the skeleton with boron-containing phenolic aerogel by adopting a pressurized potting process, and carrying out gradient drying and curing to obtain the lightweight composite material. The density of the composite material is less than or equal to 0.50 g / cm, and the linear ablation rate of high-ablation resistance at 1000 DEG C is less than or equal to 0.01 mm / The multi-dimensional composite structure with light weight and high interface bonding strength is designed by combining an additive manufacturing technology with a sol-gel potting process, the ablation resistance of the material at high temperature is remarkably improved, and the material is suitable for thermal protection systems of rocket engines and hypersonic aircrafts.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature heat insulation composite materials, and particularly relates to an additive-manufactured boron phenolic aerogel multi-dimensional skeleton composite material and a preparation method thereof. Background Art

[0002] Although traditional heat insulation materials such as carbon / phenolic resin composites have certain ablation resistance, they have problems such as high density (usually > 0.8 g / cm 3 ), easy cracking at high temperatures, and insufficient ablation resistance (linear ablation rate > 0.05 mm / min). Although aerogel materials are lightweight and have excellent heat insulation performance, their mechanical strength is low, making it difficult to be used alone in high-shear environments and unable to meet the stringent requirements of the new generation of hypersonic aircraft for lightweight thermal protection materials.

[0003] In the prior art, for traditional heat insulation carbon / phenolic resin composites, the mechanical properties of resin-based composites are increased by introducing ceramic skeletons. For example, in the article "Preparation and Mechanical Properties of Three-Dimensional Network Ceramic Skeleton Reinforced Resin Matrix Composites" by Pan Meijuan, epoxy resin was infiltrated into a three-dimensional network ceramic skeleton under vacuum pressure to successfully prepare a new type of SiC 3D / epoxy resin composite material; in order to obtain better mechanical properties of such composites, the coupling agent KH550 was used to modify the interface of the two phases of the composites. The results showed that the density of the prepared composite material was 2.85 g / cm 3 , the relative density could reach more than 99%, and its compressive strength was 250 MPa. In the article "Preparation and Properties of Three-Dimensional Network SiC Ceramic / Al Composites" by Xiao Qing, a three-dimensional network SiC ceramic was first prepared by the organic foam impregnation method, with a porosity of 80% and a strength of 3.42 MPa, which could be used to prepare composites; subsequently, a three-dimensional network SiC ceramic / Al composite material was prepared by the in-situ reaction pressureless infiltration method; it was found that the incorporation of Mg affected the infiltration depth of the material. When its content was less than 5%, the infiltration effect was poor, and an addition amount of 8% was more appropriate; the addition of Si powder could control the interfacial reaction of the composite material and inhibit the formation of Al4C3 on the interface. By adjusting these experimental conditions, a three-dimensional network SiC ceramic / Al composite material with good interfacial bonding was prepared, with a maximum density of 2.784 g / cm 3 and a thermal conductivity of 165.38 W / m·K, and the compressive strength reached 832 MPa. For example, Application No. 201910777436.4 provides an aerogel and a preparation method and application thereof, a high-temperature heat insulation material or a lightweight heat insulation / heat protection material. The aerogel includes a phenolic skeleton and a zirconia skeleton, and the zirconia skeleton is uniformly distributed in the phenolic skeleton, and the phenolic skeleton and the zirconia skeleton form a molecular network structure.

[0004] The above-prepared ceramic-skeleton-reinforced composite material increases the mechanical properties of the resin-based composite material by introducing a ceramic skeleton, but the interface combination between the skeleton and the matrix is poor, and it is difficult to control the pore structure. Summary of the Invention

[0005] To solve the above problems, the present invention provides an additive-manufactured boron phenolic aerogel multi-dimensional skeleton composite material and a preparation method thereof. By combining the additive manufacturing technology with the sol-gel encapsulation process, a lightweight and high-interface-bonding-strength multi-dimensional composite structure is designed, significantly improving the anti-ablative performance of the material at high temperatures.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] The first object of the present invention is to provide a preparation method of an additive-manufactured boron phenolic aerogel multi-dimensional skeleton composite material, including the following steps: S1. Using zirconium boride ceramic slurry as a raw material, performing photocuring 3D printing to form a zirconium boride ceramic skeleton precursor, and sintering it in a protective atmosphere to obtain a porous skeleton.

[0008] S2. Using the sol-gel method, dissolving the boron-modified phenolic resin prepolymer in a solvent, and then adding an amine catalyst to form a boron phenolic aerogel precursor solution.

[0009] S3. Using the method of pressure encapsulation, filling the boron phenolic aerogel precursor solution into the porous skeleton at 0.2 MPa to 2 MPa, and performing gradient drying and then curing to obtain the boron phenolic aerogel multi-dimensional skeleton composite material.

[0010] Further, the gradient drying method adopts three-stage drying. The drying temperature in the first stage is 30°C to 500°C, and the time is 10 h to 14 h. The curing temperature in the second stage is 55°C to 65°C, and the time is 5 h to 8 h. The curing temperature in the third stage is 70°C to 90°C, and the time is 2 h to 4 h.

[0011] Further, the porosity of the porous skeleton is 60% to 85%, and the pore diameter is 10 μm to 200 μm.

[0012] Further, the dosage ratio of the boron-modified phenolic resin prepolymer, the first amine catalyst, and the solvent is 1 g: 0.02 g to 0.4 g: 2 mL to 25 mL. The first amine catalyst is triethylamine, ethylenediamine, or hexamethylenetetramine, and the curing temperature is 240°C to 260°C.

[0013] Further, the preparation method of the boron-modified phenolic resin prepolymer includes the following steps: Step 1. Mix boric acid and phenol and perform an esterification reaction to obtain a borate ester.

[0014] Step 2: mixing boric acid ester, polyformaldehyde and a second amine catalyst to form a reaction system, and performing a polymerization reaction to form a prepolymer.

[0015] Furthermore, the molar ratio of boric acid to phenol is 1:3-5, the temperature of the esterification reaction is 100°C-130°C, and the time is 2h-4h.

[0016] Furthermore, the molar ratio of borate ester to paraformaldehyde is 1:1.2-1.5, the polymerization temperature is 80°C-100°C, and the time is 2h-4h.

[0017] Furthermore, the amount of the second amine catalyst used is 0.5wt.% to 2wt.% of the total mass of the reaction system, and the amine catalyst is triethylamine, ethylenediamine or hexamethylenetetramine.

[0018] Furthermore, the sintering temperature is 1600° C. to 1800° C., and the sintering time is 2 h to 4 h.

[0019] The second object of the present invention is to provide a boron phenolic aerogel multi-dimensional skeleton composite material, which is prepared by the above-mentioned preparation method.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The method for preparing a boron phenolic aerogel multi-dimensional skeleton composite material provided by the present invention is based on the coordinated design of a boron-modified phenolic resin and a ZrB2 ceramic skeleton, prepares a ZrB2 ceramic skeleton by 3D printing technology, prepares a boron-modified phenolic resin sol by a sol-gel method, and pioneers a pressurized potting-gradient drying process, injects a boron-modified phenolic resin sol (boron phenolic aerogel precursor solution) into the skeleton pores under a pressure of 0.2MPa to 2MPa, and uses a gradient drying and curing method so that the aerogel fully penetrates the skeleton pores under pressurized potting to form a chemical bonding interface, a dense interface bonding, and avoids high-temperature stratification, and finally forms a ceramic-aerogel interpenetrating network structure. The prepared boron phenolic aerogel multi-dimensional skeleton composite material has a ZrB2 skeleton that provides a high-temperature antioxidant barrier, and the nanoporous structure of the aerogel effectively blocks heat flow, and the synergistic effect reduces the linear ablation rate by one order of magnitude compared with traditional materials.

[0021] The present invention uses 3D printing technology to prepare a ZrB2 ceramic skeleton, and obtains a porous skeleton by sintering. The skeleton has a high porosity of 60% to 85%, and a multi-level pore structure with a pore size distribution of 10 μm to 200 μm, which ensures the effective infusion of aerogel. The phenolic resin is modified by boron, and the boron content is controlled at 5wt% to 8wt%, which not only maintains the carbon-forming properties of the resin matrix, but also enhances the thermal stability through the BO bond.

[0022] The boron phenolic aerogel multi-dimensional skeleton composite material prepared by the present invention has ultra-light characteristics: composite density ≤0.50g / cm 3, which is more than 58.3% lower than traditional materials; Ablation resistance: The oxyacetylene ablation test at 1000°C shows that the linear ablation rate ≤ 0.01 mm / min, and the back temperature rise rate is reduced to 15°C / s; Structural stability: The strength retention rate is > 85% after the thermal shock test (1000°C → room temperature, 50 cycles); It is applicable to the thermal protection system in the extreme thermal environment of the aerospace field. Brief Description of the Drawings

[0023] Figure 1 It is the structural diagram of the boron phenolic aerogel multi-dimensional skeleton composite material prepared in Example 1 of the present invention. Figure 1 In Figure a, it is the boron phenolic aerogel multi-dimensional skeleton composite material, Figure b is the SEM image at a size of 200 μm, Figure c is the SEM image at a size of 10 μm, and Figure d is the SEM image at a size of 1 μm.

[0024] Figure 2 It is the structural diagram of the ZrB2 ceramic porous skeleton prepared in Example 1 of the present invention. Detailed Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the following embodiments of the present invention can be obtained through the market or prepared by existing methods.

[0027] Although the existing ceramic skeleton reinforced composite materials can improve the mechanical properties, the interface between the skeleton and the matrix is poorly combined, the pore structure regulation is difficult, and the preparation process is complex. Based on the above problems, the present invention provides a preparation method for an additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material, including the following steps:

[0028] S1. Using zirconium boride ceramic slurry as the raw material, performing photocuring 3D printing to form a zirconium boride ceramic skeleton precursor, and sintering it in a protective atmosphere to obtain a porous skeleton.

[0029] S2. Adopting the sol-gel method, dissolving the boron-modified phenolic resin prepolymer in a solvent, and then adding a first amine catalyst to form a boron phenolic aerogel precursor solution.

[0030] S3. In a pressure-sealing manner, fill the porous framework with the boron phenolic aerogel precursor solution at 0.2 MPa to 2 MPa, and perform curing after gradient drying to obtain the boron phenolic aerogel multi-dimensional framework composite material.

[0031] The preparation method of the boron phenolic aerogel multi-dimensional framework composite material provided by the present invention is based on the collaborative design of boron-modified phenolic resin and ZrB2 ceramic framework. The ZrB2 ceramic framework is prepared by 3D printing technology, and the boron-modified phenolic resin sol is prepared by the sol-gel method. The pressure-sealing - gradient drying process is pioneered. Under the pressure of 0.2 MPa to 2 MPa, the boron-modified phenolic resin sol (boron phenolic aerogel precursor solution) is injected into the pores of the framework, and after gradient drying and curing, the aerogel fully penetrates the pores of the framework under pressure-sealing to form a chemical bonding interface, forming a dense interface combination, avoiding high-temperature delamination, and finally forming a ceramic-aerogel interpenetrating network structure. For the prepared boron phenolic aerogel multi-dimensional framework composite material, its ZrB2 framework provides a high-temperature antioxidant barrier, and the nano-porous structure of the aerogel effectively blocks heat flow. The synergistic effect reduces the linear ablation rate by one order of magnitude compared with traditional materials.

[0032] In a specific embodiment, the gradient drying method adopts three-stage drying and curing. The temperature of the first-stage drying is 30°C to 50°C, and the time is 10 h to 14 h. The temperature of the second-stage drying is 55°C to 65°C, and the time is 5 h to 8 h. The temperature of the third-stage drying is 70°C to 90°C, and the time is 2 h to 4 h. It should be noted that the present invention adopts the vacuum pressure-sealing - gradient drying process. Through the three-stage drying method, the boron phenolic aerogel fully penetrates the pores of the framework under pressure-sealing to form a chemical bonding interface, forming a dense interface combination, avoiding high-temperature delamination, and finally forming a ceramic-aerogel interpenetrating network structure. Among them, the gradient drying adopts the critical CO2 drying method. For the obtained aerogel, the density of the aerogel is 0.1 g / cm 3 ~0.12 g / cm 3 .

[0033] In a specific embodiment, the porosity of the porous framework is 60% to 85%, and the pore diameter is 10 μm to 200 μm. It should be noted that during the preparation of the porous framework, zirconium boride ceramic slurry is prepared by mixing nano-ZrB2 powder (D 50 = 200 nm) and photosensitive resin in a volume ratio of 7:3. After forming by 3D printing technology (DLP printing), among them, during the 3D printing process, the layer thickness is 20 μm to 50 μm, and the light intensity is 8 mW / cm 2 ~12 mW / cm 2, a porous framework is obtained through parameter optimization and sintering in a protective atmosphere to achieve a high porosity of the porous framework, and a multi-level pore structure with a pore size of 10 μm to 200 μm is formed to ensure effective perfusion of the aerogel. In a preferred embodiment, during the 3D printing process, the layer thickness is 40 μm and the light intensity is 10 mW / cm 2 .

[0034] In a specific embodiment, the dosage ratio of the boron-modified phenolic resin prepolymer, the first amine catalyst, and the solvent is 1 g: 0.02 g to 0.4 g: 2 mL to 25 mL. The first amine catalyst is triethylamine, ethylenediamine, or hexamethylenetetramine, and the curing temperature is 240°C to 260°C.

[0035] In a specific embodiment, the preparation method of the boron-modified phenolic resin prepolymer includes the following steps: Step 1, mix boric acid and phenol and carry out an esterification reaction to obtain a borate ester.

[0036] Step 2, mix the borate ester, paraformaldehyde, and the second amine catalyst to form a reaction system and carry out a polymerization reaction to form a prepolymer.

[0037] It should be noted that in the present invention, the hydroxyl group of boric acid undergoes a condensation reaction with the hydroxyl group of phenol. Under the action of the second amine catalyst, paraformaldehyde decomposes into formaldehyde, and formaldehyde undergoes an electrophilic substitution reaction with the free phenolic hydroxyl group remaining in the borate ester to generate a hydroxymethylphenol structure prepolymer. The reaction efficiency of the preparation method is high, the yield is above 80%, and the polymer molecular weight is about 500.

[0038] In a specific embodiment, the molar ratio of boric acid to phenol is 1: 3 to 5, the temperature of the esterification reaction is 100°C to 130°C, and the time is 2 h to 4 h. It should be noted that in the present invention, by controlling the dosage of boric acid, the boron content of the boron-modified phenolic resin prepolymer is controlled at 5 wt.% to 8 wt.%, which not only maintains the carbon-forming characteristics of the resin matrix but also enhances the thermal stability through the B-O bond.

[0039] In a specific embodiment, the molar ratio of the borate ester to paraformaldehyde is 1: 1.2 to 1.5, the temperature of the polymerization reaction is 80°C to 100°C, and the time is 2 h to 4 h.

[0040] In a specific embodiment, the dosage of the second amine catalyst is 0.5 wt.% to 2 wt.% of the total mass of the reaction system, and the second amine catalyst is triethylamine, ethylenediamine, or hexamethylenetetramine.

[0041] In a specific embodiment, the sintering temperature is 1600°C to 1800°C, and the time is 2 h to 5 h.

[0042] In addition, the present invention also provides a boron phenolic aerogel multi-dimensional skeleton composite material, which has ultra-light characteristics: the composite density ≤ 0.50 g / cm 3 , which is more than 58.3% lower than that of traditional materials; ablation resistance: the oxyacetylene ablation test at 1000 °C shows that the linear ablation rate ≤ 0.01 mm / min, and the back temperature rise rate is reduced to 15 °C / s; structural stability: the strength retention rate > 85% after the thermal shock test (1000 °C → room temperature, 50 cycles); it is applicable to the thermal protection system in extreme thermal environments in the aerospace field.

[0043] The following is further illustrated by specific examples.

[0044] Example 1 A preparation method of an additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material includes the following steps: S1. Preparation of boron-modified phenolic resin prepolymer: Mix 0.1 mol of boric acid with 0.4 mol of phenol, carry out an esterification reaction at 120 °C for 3 h to obtain a transparent borate ester; mix the prepared transparent borate ester with 0.12 mol of paraformaldehyde to form a reaction system, add 1 wt% of triethylamine based on the total mass of the reaction system, and carry out a polymerization reaction at 90 °C for 2 h to obtain a viscous resin, which is the boron-modified phenolic resin prepolymer.

[0045] S2. Preparation of boron phenolic aerogel precursor solution: Adopt the sol-gel method, weigh 10 g of the prepared boron-modified phenolic resin prepolymer, dissolve it in 50 mL of ethanol, then add 0.8 g of hexamethylenetetramine, and stir for 30 min to form a boron phenolic aerogel precursor solution.

[0046] S3. Preparation of porous skeleton: Mix nano-ZrB2 powder (D 50 = 200 nm) and photosensitive resin in a volume ratio of 7:3 to prepare a zirconium boride ceramic slurry, and adopt the digital light processing (DLP) technology printing method to carry out photocuring 3D printing to form a zirconium boride ceramic skeleton precursor, and sinter it at 1700 °C for 2 h in an argon atmosphere to obtain a ZrB2 ceramic porous skeleton.

[0047] S3. Preparation of boron phenolic aerogel multi-dimensional skeleton composite material: Adopt the pressure potting method to fill the boron phenolic aerogel precursor solution into the porous skeleton at 1 MPa, and adopt the critical CO2 drying method for gradient drying. The drying and curing temperature in the first stage is 40 °C, and the time is 12 h. The drying and curing temperature in the second stage is 60 °C, and the time is 6 h. The drying and curing temperature in the third stage is 80 °C, and the time is 3 h. Subsequently, post-curing treatment is carried out at 250 °C to obtain the boron phenolic aerogel multi-dimensional skeleton composite material.

[0048] Example 2 A preparation method of an additive - manufactured boron - phenolic aerogel multi - dimensional skeleton composite material, comprising the following steps: S1. Preparation of boron - modified phenolic resin prepolymer: Mix 0.1 mol of boric acid with 0.5 mol of phenol, carry out an esterification reaction at 120 °C for 3 h to obtain a transparent borate ester; mix the prepared transparent borate ester with 0.15 mol of paraformaldehyde to form a reaction system, add 1.5 wt% of triethylamine based on the total mass of the reaction system, and carry out a polymerization reaction at 100 °C for 3 h to obtain a viscous resin, which is the boron - modified phenolic resin prepolymer.

[0049] S2. Preparation of boron - phenolic aerogel precursor solution: Adopt the sol - gel method, weigh 8 g of the prepared boron - modified phenolic resin prepolymer, dissolve it in 40 mL of ethanol, then add 0.6 g of hexamethylenetetramine, and stir for 30 min to form a boron - phenolic aerogel precursor solution.

[0050] S3. Preparation of porous skeleton: Mix nano - ZrB2 powder (D 50 = 200 nm) and photosensitive resin according to a volume ratio of 7:3 to prepare a zirconium boride ceramic slurry, and adopt the digital light processing (DLP) technology printing method to carry out photocuring 3D printing to form a zirconium boride ceramic skeleton precursor, and sinter it at 1800 °C for 2 h in an argon atmosphere to obtain a ZrB2 ceramic porous skeleton.

[0051] S3. Preparation of boron - phenolic aerogel multi - dimensional skeleton composite material: Adopt the pressure - filling and sealing method, fill the boron - phenolic aerogel precursor solution into the porous skeleton at 1 MPa, and after gradient drying and curing, the temperature of the first - stage drying and curing is 45 °C, the time is 10 h, the temperature of the second - stage drying and curing is 65 °C, the time is 5 h, the temperature of the third - stage drying and curing is 90 °C, the time is 2 h, and then obtain the boron - phenolic aerogel multi - dimensional skeleton composite material through post - curing treatment at 250 °C.

[0052] Example 3 A preparation method of an additive - manufactured boron - phenolic aerogel multi - dimensional skeleton composite material, comprising the following steps: S1. Preparation of boron - modified phenolic resin prepolymer: Mix 0.1 mol of boric acid with 0.3 mol of phenol and carry out an esterification reaction at 120 °C for 3 h to obtain a transparent borate ester; mix the above-prepared transparent borate ester with 0.13 mol of paraformaldehyde to form a reaction system, add 0.5 wt% of triethylamine based on the total mass of the reaction system, and carry out a polymerization reaction at 90 °C for 3 h to obtain a viscous resin, which is the boron-modified phenolic resin prepolymer.

[0053] S2. Preparation of the boron phenolic aerogel precursor solution: Using the sol-gel method, weigh 5 g of the above-prepared boron-modified phenolic resin prepolymer, dissolve it in 30 mL of ethanol, then add 0.4 g of hexamethylenetetramine, and stir for 30 min to form a boron phenolic aerogel precursor solution.

[0054] S3. Preparation of the porous framework: Mix nano-ZrB2 powder (D 50 = 200 nm) and a photosensitive resin in a volume ratio of 7:3 to prepare a zirconium boride ceramic slurry. Using the digital light processing (DLP) technology printing method, carry out photocuring 3D printing to form a zirconium boride ceramic framework precursor, and sinter it at 1600 °C for 3 h in an argon atmosphere to obtain a ZrB2 ceramic porous framework.

[0055] S3. Preparation of the boron phenolic aerogel multi-dimensional framework composite material: Using the pressure potting method, fill the boron phenolic aerogel precursor solution into the porous framework at 1 MPa, and after gradient drying and curing, the temperature of the first-stage drying and curing is 35 °C, the time is 14 h, the temperature of the second-stage drying and curing is 55 °C, the time is 8 h, the temperature of the third-stage drying and curing is 70 °C, the time is 4 h, and then obtain the boron phenolic aerogel multi-dimensional framework composite material through post-curing treatment at 250 °C.

[0056] Comparative Example 1 A preparation method of a carbon / phenolic composite material includes the following steps: Impregnate carbon fiber felt with phenolic resin, take it out and dry it after impregnation, and then carry out high-temperature carbonization at 1700 °C for 3 h in a nitrogen atmosphere to obtain a carbon / phenolic composite material.

[0057] Test the structure and properties of the boron phenolic aerogel multi-dimensional framework composite material prepared in Example 1, and the results are as follows: Figure 1 This is the structure diagram of the boron phenolic aerogel multi-dimensional framework composite material prepared in Example 1 of the present invention. Figure 1 In Figure a is the boron phenolic aerogel multi-dimensional framework composite material, Figure b is the SEM image at a size of 200 μm, Figure c is the SEM image at a size of 10 μm, and Figure d is the SEM image at a size of 1 μm. As Figure 1As shown, an interpenetrating network of the ZrB2 framework (gray) and the aerogel (black) is shown.

[0058] Figure 2 This is the structural diagram of the ZrB2 ceramic porous framework prepared in Example 1 of the present invention. As Figure 2 shown, a uniform porous structure is shown.

[0059] The material density and the linear ablation rate at 1000 °C of the composite materials prepared in Example 1 and Comparative Example 1 were tested. The results are shown in Table 1. Among them, the linear ablation rate at 1000 °C was tested according to the test method of GJB 323B-2018.

[0060] Table 1 Performance data of the composite materials prepared in Example 1 and Comparative Example 1 As shown in Table 1, under the same test conditions, the density of the composite material prepared in Example 1 of the present invention is 0.45 g / cm 3 , and the linear ablation rate at 1000 °C is 0.01 mm / min. While the density of the composite material prepared in Comparative Example 1 is 1.2 g / cm 3 , and the linear ablation rate is 0.12 mm / min. Compared with Comparative Example 1, the ablation rate of the composite material prepared by the present invention is reduced by 91.7%.

[0061] It should be noted that when the present invention relates to a numerical range, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the adopted step method is the same as that of the embodiment, in order to prevent repetition, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0062] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A preparation method of an additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material, characterized in that It includes the following steps: Using zirconium boride ceramic slurry as raw material, performing photocuring 3D printing to form a zirconium boride ceramic framework precursor, and sintering it under a protective atmosphere to obtain a porous framework; Adopting the sol-gel method, dissolving the boron-modified phenolic resin prepolymer in a solvent, and adding a first amine catalyst to form a boron phenolic aerogel precursor solution; Adopting the method of pressure encapsulation, filling the boron phenolic aerogel precursor solution into the porous framework at 0.2 MPa to 2 MPa, and performing gradient drying and then curing to obtain a boron phenolic aerogel multi-dimensional framework composite material.

2. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 1, characterized in that, The way of gradient drying adopts three-stage drying. The temperature of the first-stage drying is 30°C to 500°C, and the time is 10 h to 14 h. The curing temperature of the second stage is 55°C to 65°C, and the time is 5 h to 8 h. The curing temperature of the third stage is 70°C to 90°C, and the time is 2 h to 4 h.

3. The preparation method of the additive manufactured boron phenolic aerogel multi-dimensional skeleton composite material according to claim 1, characterized in that, The porosity of the porous framework is 60% to 85%, and the pore diameter is 10 μm to 200 μm.

4. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 1, characterized in that, The dosage ratio of the boron-modified phenolic resin prepolymer, the first amine catalyst and the solvent is 1 g: 0.02 g to 0.4 g: 2 mL to 25 mL. The first amine catalyst is triethylamine, ethylenediamine or hexamethylenetetramine, and the curing temperature is 240°C to 260°C.

5. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 1, characterized in that, The preparation method of the boron-modified phenolic resin prepolymer includes the following steps: Mixing boric acid and phenol, and performing an esterification reaction to obtain a borate ester; Mixing the borate ester, paraformaldehyde and a second amine catalyst to form a reaction system, and performing a polymerization reaction to form a prepolymer.

6. The preparation method of the additive manufactured boron phenolic aerogel multi-dimensional skeleton composite material according to claim 5, characterized in that, The molar ratio of boric acid to phenol is 1: 3 to 5, the temperature of the esterification reaction is 100°C to 130°C, and the time is 2 h to 4 h.

7. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 5, characterized in that The molar ratio of the borate ester to paraformaldehyde is 1: 1.2 to 1.5, the temperature of the polymerization reaction is 80°C to 100°C, and the time is 2 h to 4 h.

8. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 5, characterized in that, The dosage of the amine catalyst is 0.5 wt.% to 2 wt.% of the total mass of the reaction system. The second amine catalyst is triethylamine, ethylenediamine or hexamethylenetetramine.

9. The preparation method of the additive manufacturing boron phenolic aerogel multi-dimensional skeleton composite material according to claim 1, characterized in that, The sintering temperature is 1600°C to 1800°C, and the time is 2 h to 4 h.

10. A boron phenolic aerogel multi-dimensional framework composite material, characterized in that, Prepared by using the preparation method described in any one of claims 1 to 9.

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