Ablation-resistant high-silicon-oxygen-carbon fiber composite material and a preparation method thereof

Abstract

The application provides a kind of ablation-resistant high-silicon-oxygen-carbon fiber composite material and a preparation method thereof, and belongs to the field of carbon fiber composite materials.The ablation-resistant high-silicon-oxygen-carbon fiber composite material provided by the application has a specific layered structure, and a water glass fiber composite layer is arranged on the outer side of the composite material as an ablation-resistant layer to improve the ablation-resistant performance of the composite material; a phenolic fiber composite layer serves as a support layer to provide good mechanical strength and improve the mechanical properties of the composite material; meanwhile, each component fully plays its role during use, further improving the ablation-resistant performance and mechanical properties of the composite material.The experimental results show that the overall ablation rate of the ablation-resistant high-silicon-oxygen-carbon fiber composite material provided by the application is 0.05-0.14 g / s, the tensile strength is 15.92-33.17 MPa, the bending strength is 12.98-22.14 MPa, and the compressive strength is 48.67-55.63 MPa.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber composite materials, and more specifically to an ablation-resistant high-silica carbon fiber composite material and its preparation method. Background Technology

[0002] Currently, with the rapid development of aerospace, military, and other fields, ablation-resistant materials are playing an increasingly important role. In the aerospace field, carbon fiber composites possess excellent resistance to high-temperature combustion gases and high-temperature ablation; moreover, they are lightweight, high-strength, easy to mold, and corrosion-resistant, making them widely used in the preparation of ablation materials. High-silica glass fiber composites are a melting-type ablation material with a low thermal conductivity, allowing them to be used in harsher high-temperature environments. Carbon fiber high-silica composites are mainly composed of carbon fibers and high-silica glass fibers, inheriting the excellent structural and thermal properties of both.

[0003] Patent CN111253860A uses hydroxyl-terminated polydimethylsiloxane as the main component, combined with octaglycidyl etheroxypropyl, to prepare an ablation-resistant silicone resin material, improving its ablation resistance. However, the mechanical properties of the composite material are still poor and cannot meet practical application requirements. Patent CN116675951A uses fluorinated epoxy resin and carbon fiber to prepare a composite material, which has certain corrosion resistance and high specific strength, but its ablation resistance is not ideal. It is evident that commonly used ablation-resistant composite materials in the prior art cannot simultaneously meet the requirements of both mechanical properties and ablation resistance. Summary of the Invention

[0004] The purpose of this invention is to provide an ablation-resistant high-silica carbon fiber composite material, which has good ablation resistance and mechanical properties.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides an ablation-resistant high-silica carbon fiber composite material, comprising water glass fiber composite layers and phenolic fiber composite layers arranged alternately from the outside to the inside;

[0007] The water glass fiber composite layer comprises the following components in parts by weight:

[0008] 50-75 parts of carbon fiber short fibers

[0009] 50-70 parts of high-silica glass fiber short fibers

[0010] 15-25 parts of surfactant

[0011] 3-5 parts of sodium fluorosilicate

[0012] 4-5 parts aluminum sulfate

[0013] 4-5 parts of antimony trioxide

[0014] 60-80 parts of water glass;

[0015] The phenolic fiber composite layer comprises the following components in parts by weight:

[0016] 50-75 parts of carbon fiber short fibers

[0017] 50-70 parts of high-silica glass fiber short fibers

[0018] 15-25 parts of surfactant

[0019] 3-5 parts of sodium fluorosilicate

[0020] 4-5 parts aluminum sulfate

[0021] 4-5 parts of antimony trioxide

[0022] 11-17 parts of boron-modified phenolic resin solution.

[0023] Preferably, the water glass fiber composite layer comprises the following components in parts by weight:

[0024] 60-65 parts of carbon fiber short fibers

[0025] 55-60 parts of high-silica glass fiber short fibers

[0026] 16-18 parts of surfactant

[0027] Sodium fluorosilicate 3.5~3.8 parts

[0028] 4.2-4.4 parts aluminum sulfate

[0029] Antimony trioxide 4.2~4.4 parts

[0030] 65-70 parts of water glass;

[0031] The phenolic fiber composite layer comprises the following components in parts by weight:

[0032] 60-65 parts of carbon fiber short fibers

[0033] 55-60 parts of high-silica glass fiber short fibers

[0034] 16-18 parts of surfactant

[0035] Sodium fluorosilicate 3.5~3.8 parts

[0036] 4.2-4.4 parts aluminum sulfate

[0037] Antimony trioxide 4.2~4.4 parts

[0038] 13-14 parts of boron-modified phenolic resin solution.

[0039] Preferably, the mass ratio of surfactant, sodium fluorosilicate, aluminum sulfate and antimony trioxide in the water glass fiber composite layer and the phenolic fiber composite layer is independently (30~50):(6~10):(8~10):(8~10).

[0040] Preferably, the thickness of the water glass fiber composite layer and the phenolic fiber composite layer is independently 3~4 mm.

[0041] Preferably, the lengths of the carbon fiber short fibers and the high-silica glass fiber short fibers are independently 0.5~1mm.

[0042] The present invention also provides a method for preparing the high-silica carbon fiber composite material described in the above technical solution, comprising the following steps:

[0043] (1) Mix carbon fiber short fibers, high silica glass fiber short fibers, surfactants, sodium fluorosilicate, aluminum sulfate and antimony trioxide to obtain mixed fibers;

[0044] (2) Divide the mixed fibers obtained in step (1) into two equal parts. Mix one part with water glass solution to obtain water glass fiber mixture, and mix the other part with boron modified phenolic resin solution to obtain phenolic fiber mixture.

[0045] (3) The water glass fiber mixture and phenolic fiber mixture obtained in step (2) are alternately laid flat, with the water glass fiber mixture placed on the outermost layer, and then heated and pressurized to obtain the molded body;

[0046] (4) The molded body obtained in step (3) is cured to obtain a high silica carbon fiber composite material.

[0047] Preferably, the carbon fiber short fibers and high-silica glass fiber short fibers in step (1) are pretreated before use. The pretreatment includes: immersing the carbon fiber short fibers and high-silica glass fiber short fibers in sodium hydroxide solution and then drying them.

[0048] Preferably, the solvent for the boron-modified phenolic resin solution in step (2) is methanol, and the mass ratio of the boron-modified phenolic resin to methanol is 1:(5~6).

[0049] Preferably, the heating and pressurizing process in step (3) adopts a programmed temperature and pressure increase, including: a first stage of heating to 100~120℃ and pressurizing to 0~1MPa, with a holding time of 20~30min; a second stage of heating to 130~160℃ and pressurizing to 2~4MPa, with a holding time of 20~40min; a third stage of heating to 170~175℃ and pressurizing to 5~8MPa, with a holding time of 30~40min; and a fourth stage of heating to 180~200℃ and pressurizing to 18~20MPa, with a holding time of 10~20min.

[0050] Preferably, the curing temperature in step (4) is 170~180℃ and the curing time is 12~13h.

[0051] This invention provides an ablation-resistant high-silica carbon fiber composite material, comprising alternating layers of water glass fiber and phenolic fiber from the outside in. The water glass fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers, 50-70 parts of high-silica glass fiber short fibers, 15-25 parts of surfactant, 3-5 parts of sodium fluorosilicate, 4-5 parts of aluminum sulfate, 4-5 parts of antimony trioxide, and 60-80 parts of water glass. The phenolic fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers, 50-70 parts of high-silica glass fiber short fibers, 15-25 parts of surfactant, 3-5 parts of sodium fluorosilicate, 4-5 parts of aluminum sulfate, 4-5 parts of antimony trioxide, and 11-17 parts of boron-modified phenolic resin. The composite material provided by this invention has a specific layered structure. A water glass fiber composite layer, serving as an ablation-resistant layer, is disposed on the outer side of the composite material to improve its ablation resistance. Water glass fiber composite layers and phenolic fiber composite layers are alternately arranged, with the phenolic fiber composite layer acting as a support layer to provide good mechanical strength and improve the mechanical properties of the composite material. During use, the phenolic resin in the phenolic fiber composite layer decomposes upon heating, absorbing heat and generating pyrolysis gas to form a pyrolysis layer. This pyrolysis gas flows into the boundary layer between the pyrolysis layer and the liquid layer formed by the high-silica glass fiber short fibers, creating a "thermal blocking" effect. The carbon in the carbon fiber short fibers oxidizes, forming a carbonized layer. The high-silica... The silica on the surface of the short glass fiber melts, forming a liquid layer between the carbonized layer and the pyrolysis layer. The pyrolysis gases produced by the decomposition of phenolic resin continuously move towards the liquid layer. The process of silica melting to form the liquid layer absorbs heat, carrying away heat from the ablation process and improving the composite material's ablation resistance. The addition of antimony trioxide, aluminum sulfate, and sodium fluorosilicate significantly enhances the composite material's ablation resistance. Simultaneously, an endothermic reaction occurs between the high-silica glass fiber and the phenolic resin, absorbing some heat and further improving the composite material's ablation resistance. The resulting composite material also emits a certain degree of thermal radiation to the external environment, contributing to its excellent ablation resistance. The results of the embodiments show that the overall ablation rate of the composite material provided by this invention is 0.05~0.14 g / s, the tensile strength is 15.92~33.17 MPa, the flexural strength is 12.98~22.14 MPa, and the compressive strength is 48.67~55.63 MPa. Attached Figure Description

[0052] Figure 1 This is a temperature-time diagram of the programmed heating process and the curing process in Embodiment 1 of the present invention. Detailed Implementation

[0053] This invention provides an ablation-resistant high-silica carbon fiber composite material, comprising alternating layers of water glass fiber and phenolic fiber from the outside in. The water glass fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers, 50-70 parts of high-silica glass fiber short fibers, 15-25 parts of surfactant, 3-5 parts of sodium fluorosilicate, 4-5 parts of aluminum sulfate, 4-5 parts of antimony trioxide, and 60-80 parts of water glass. The phenolic fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers, 50-70 parts of high-silica glass fiber short fibers, 15-25 parts of surfactant, 3-5 parts of sodium fluorosilicate, 4-5 parts of aluminum sulfate, 4-5 parts of antimony trioxide, and 11-17 parts of boron-modified phenolic resin.

[0054] The composite material provided by the present invention includes water glass fiber composite layers and phenolic fiber composite layers arranged alternately from the outside to the inside.

[0055] In this invention, the outermost layer of the composite material is a water glass fiber composite layer. By placing the water glass fiber composite layer as the outermost ablation-resistant layer, this invention fully utilizes the ablation resistance of the water glass fiber composite layer, thereby improving the ablation resistance of the composite material.

[0056] In this invention, the water glass fiber composite layer and the phenolic fiber composite layer are alternately arranged. The phenolic fiber composite layer serves as a support layer, providing good mechanical strength and improving the mechanical properties of the composite material.

[0057] In this invention, the thicknesses of the water glass fiber composite layer and the phenolic fiber composite layer are preferably 3-4 mm, more preferably 3 mm. By selecting appropriate thicknesses for the water glass fiber composite layer and the phenolic fiber composite layer, the overall mass of the composite material is reduced while fully utilizing its ablation resistance and supporting functions, making it more suitable for the aerospace field.

[0058] In this invention, there is no particular limitation on the number of times the water glass fiber composite layer and the phenolic fiber composite layer alternate. The number of times the water glass fiber composite layer and the phenolic fiber composite layer alternate is set according to the actual required thickness of the composite material.

[0059] In this invention, the water glass fiber composite layer and the phenolic fiber composite layer, by weight, independently comprise 50-75 parts, preferably 50-70 parts, and more preferably 60-65 parts, of carbon fiber short fibers. In this invention, the carbon fiber short fibers provide support and improve the mechanical properties of the composite material; simultaneously, the carbon in the carbon fiber short fibers oxidizes during the ablation process, forming a carbonized layer that participates in the formation of the liquid layer, carrying away heat during the ablation process and improving the ablation resistance of the composite material.

[0060] In this invention, the length of the carbon fiber short fibers is preferably 0.5~1cm, more preferably 0.5~0.75cm. By selecting carbon fiber short fibers of appropriate length, the supporting capacity is improved, avoiding situations where the length is too short and the supporting effect is insignificant, or the length is too long and leads to breakage, thus reducing the mechanical properties of the composite material, thereby further improving the mechanical properties of the composite material.

[0061] In this invention, the carbon fiber short fibers are preferably one or a combination of two of T300 and T700. This invention improves the ablation resistance and mechanical properties of the composite material by selecting suitable carbon fibers, promoting their oxidation, and enhancing their support properties.

[0062] In this invention, based on a mass of 50-75 parts of carbon fiber short fibers, the water glass fiber composite layer and the phenolic fiber composite layer independently comprise 50-70 parts of high-silica glass fiber short fibers, preferably 50-65 parts, and more preferably 55-60 parts. In this invention, the silica on the surface of the high-silica glass fiber short fibers melts during the ablation process, forming a liquid layer between the carbonized layer and the pyrolysis layer formed by the decomposition of the phenolic resin. The formation of the liquid layer is heat-absorbing, carrying away the heat from the ablation process and improving the ablation resistance of the composite material. In the phenolic fiber composite layer, the high-silica glass fiber short fibers can also undergo an endothermic reaction between carbon and silicon with the phenolic resin, absorbing some heat and further improving the ablation resistance of the composite material.

[0063] In this invention, the length of the high-silica glass fiber short fibers is preferably 0.5~1cm, more preferably 0.5~0.75cm. By selecting high-silica glass fiber short fibers of suitable length, the ablation resistance of the composite material is further improved.

[0064] In this invention, based on 50-75 parts by weight of carbon fiber short fibers, the water glass fiber composite layer and the phenolic fiber composite layer independently include 15-25 parts of surfactant, preferably 15-20 parts, and more preferably 16-18 parts. In this invention, the surfactant reduces the surface tension of each component, improves the compatibility of each component, fully utilizes the role of each component, and further improves the ablation resistance and mechanical properties of the composite material.

[0065] The present invention does not have any particular limitation on the type of surfactant, and surfactants well known to those skilled in the art can be used to prepare it.

[0066] In this invention, based on 50-75 parts by weight of carbon fiber short fibers, the water glass fiber composite layer and the phenolic fiber composite layer independently comprise 3-5 parts of sodium fluorosilicate, preferably 3-4 parts, and more preferably 3.5-3.8 parts. In this invention, sodium fluorosilicate exhibits strong corrosion resistance and can form a protective sodium fluorosilicate film on the surface of the material to be protected, further improving the ablation resistance of the composite material.

[0067] In this invention, based on 50-75 parts by weight of carbon fiber short fibers, the water glass fiber composite layer and the phenolic fiber composite layer independently comprise 4-5 parts of aluminum sulfate, preferably 4-4.5 parts, and more preferably 4.2-4.4 parts. In this invention, the aluminum sulfate is decomposed by heating to form a dense alumina film, further improving the ablation resistance of the composite material.

[0068] In this invention, based on 50-75 parts by weight of carbon fiber short fibers, the water glass fiber composite layer and the phenolic fiber composite layer independently comprise 4-5 parts of antimony trioxide, preferably 4-4.5 parts, and more preferably 4.2-4.4 parts. In this invention, antimony trioxide melts during the ablation process to form a protective film, which, through internal heat absorption, lowers the ablation temperature of the material surface, further improving the ablation resistance of the composite material.

[0069] In this invention, the preferred mass ratio of surfactant, sodium fluorosilicate, aluminum sulfate, and antimony trioxide in the water glass fiber composite layer and the phenolic fiber composite layer is (30~50):(6~10):(8~10):(8~10), more preferably 30:6:8:8. By limiting the mass ratio of surfactant, sodium fluorosilicate, aluminum sulfate, and antimony trioxide, each component can fully exert its effect, further improving the ablation resistance of the composite material.

[0070] In this invention, based on a carbon fiber short fiber mass of 50-75 parts, the water glass fiber composite layer comprises 60-80 parts of water glass, preferably 60-75 parts, and more preferably 65-70 parts. In this invention, the addition of water glass, which has excellent corrosion resistance, further improves the ablation resistance of the composite material.

[0071] In this invention, based on 50-75 parts by weight of carbon fiber short fibers, the phenolic fiber composite layer comprises 11-17 parts, preferably 11-15 parts, and more preferably 13-14 parts, of boron-modified phenolic resin. In this invention, the phenolic resin decomposes upon heating, absorbing heat to generate pyrolysis gas and form a pyrolysis layer. The pyrolysis gas flows into the boundary layer, creating a "thermal blockage" effect. Simultaneously, the generated pyrolysis gas continuously moves towards the liquid layer, causing the liquid layer to carry away more heat, further improving the ablation resistance of the composite material. The use of boron-modified phenolic resin introduces inorganic boron into the molecular structure of the phenolic resin. Boron-modified phenolic resin exhibits superior heat resistance, instantaneous high-temperature resistance, and mechanical properties compared to phenolic resin, thus improving the ablation resistance of the composite material.

[0072] The ablation-resistant high-silica carbon fiber composite material provided by this invention has both excellent ablation resistance and mechanical properties, and can better meet practical needs.

[0073] The present invention also provides a method for preparing the ablation-resistant high-silica carbon fiber composite material described above, comprising the following steps:

[0074] (1) Mix carbon fiber short fibers, high silica glass fiber short fibers, surfactants, sodium fluorosilicate, aluminum sulfate and antimony trioxide to obtain mixed fibers;

[0075] (2) Divide the mixed fibers obtained in step (1) into two equal parts. Mix one part with water glass solution to obtain water glass fiber mixture, and mix the other part with boron modified phenolic resin solution to obtain phenolic fiber mixture.

[0076] (3) The water glass fiber mixture and phenolic fiber mixture obtained in step (2) are alternately laid flat, with the water glass fiber mixture placed on the outermost layer, and then heated and pressurized to obtain the molded body;

[0077] (4) The molded body obtained in step (3) is cured to obtain a high silica carbon fiber composite material.

[0078] This invention mixes carbon fiber short fibers, high-silica glass fiber short fibers, surfactants, sodium fluorosilicate, aluminum sulfate, and antimony trioxide to obtain mixed fibers.

[0079] In this invention, the carbon fiber short fibers and high-silica glass fiber short fibers are preferably pretreated before use; the pretreatment preferably includes: immersing the carbon fiber short fibers and high-silica glass fiber short fibers in sodium hydroxide solution and then drying them.

[0080] In this invention, the concentration of the sodium hydroxide solution is preferably 0.1~0.3 mol / L, more preferably 0.1 mol / L; the wetting time is preferably 1.5~2 h, more preferably 2 h. In this invention, by controlling the concentration and wetting time of the sodium hydroxide solution used to wet the carbon fiber short fibers and high-silica glass fiber short fibers, the surfaces of the carbon fiber short fibers and high-silica glass fiber short fibers can be thoroughly cleaned, increasing their wettability and further improving the ablation resistance and mechanical properties of the composite material.

[0081] In this invention, the drying temperature is preferably 80~100℃, more preferably 80℃; the drying time is preferably 20~24h, more preferably 20h.

[0082] After obtaining the mixed fibers, the present invention divides the mixed fibers into two equal parts. One part is mixed with a water glass solution to obtain a water glass fiber composite layer, and the other part is mixed with a boron-modified phenolic resin solution to obtain a phenolic fiber composite layer.

[0083] In this invention, the water glass solution is a mixed solution of water glass and water; the mass ratio of water glass to water is 1:(4~5).

[0084] In this invention, the mixing of the mixed fibers with the water glass solution is preferably carried out by immersing the mixed fibers in the water glass solution; the immersion time is preferably 10-12 hours, more preferably 10 hours. In this application, by limiting the immersion time of the mixed fibers in water glass, the mixed fibers can be fully dissolved, and the components can be fully contacted, thereby further improving the ablation resistance of the composite material.

[0085] In this invention, the solvent for the boron-modified phenolic resin solution is preferably methanol; the mass ratio of the boron-modified phenolic resin to methanol is preferably 1:(5~6), more preferably 1:5. By limiting the mass ratio of the boron-modified phenolic resin to methanol, the solubility and flowability of the phenolic resin are improved, allowing it to react better with other components and enhancing the ablation resistance of the composite material.

[0086] In this invention, the boron-modified phenolic resin is preferably a boron-modified phenolic resin product prepared by Jining Tangyi Chemical Co., Ltd., with the product brand name TY-04.

[0087] In this invention, the mixing of the mixed fibers with the boron-modified phenolic resin solution is preferably carried out by immersing the mixed fibers in the boron-modified phenolic resin solution; the immersion time is preferably 10-12 hours, more preferably 10 hours. By limiting the immersion time of the mixed fibers in the boron-modified phenolic resin solution, this invention ensures that the mixed fibers are fully dissolved and that the components are in full contact, thereby further improving the ablation resistance of the composite material.

[0088] After obtaining the water glass fiber composite layer and the phenolic fiber composite layer, the present invention alternately lays the water glass fiber composite layer and the phenolic fiber composite layer flat, with the water glass fiber composite layer placed on the outermost layer, and then performs heating and pressurization treatment to obtain the molded body.

[0089] The present invention does not impose any special limitations on the tiling operation; any technical means known to those skilled in the art can be used.

[0090] In this invention, the heating and pressurizing treatment preferably employs a programmed temperature and pressure increase method, comprising: a first stage preferably heating to 100~120℃, more preferably 100℃; preferably pressurizing to 0~1MPa, more preferably 0MPa; and holding the temperature and pressure for 20~30min, more preferably 20min; a second stage preferably heating to 130~160℃, more preferably 130℃; preferably pressurizing to 2~4MPa, more preferably 2MPa; and holding the temperature and pressure for 20~40min, more preferably 20min; a third stage preferably heating to 170~175℃, more preferably 170℃; preferably pressurizing to 5~8MPa, more preferably 5MPa; and holding the temperature and pressure for 30~40min, more preferably 30min; and a fourth stage preferably heating to 180~200℃, more preferably 180℃; preferably pressurizing to 18~20MPa, more preferably 18MPa; and holding the temperature and pressure for 10~20min, more preferably 10min. In this invention, by limiting the temperature, pressure and time, the raw materials are allowed to come into full contact, giving full play to their functions and further improving the ablation resistance of the composite material.

[0091] After obtaining the molded body, the present invention cures the molded body to obtain a high-silica carbon fiber composite material.

[0092] In this invention, the curing temperature is preferably 170~180℃, more preferably 170℃, and the curing time is preferably 12~13h, more preferably 12h. In this invention, by limiting the curing temperature and time, the raw materials are allowed to fully contact and react, further improving the ablation resistance of the composite material.

[0093] After curing, the present invention preferably cools the cured product naturally to room temperature to obtain an ablation-resistant high-silica carbon fiber composite material.

[0094] The method for preparing ablation-resistant high-silica carbon fiber composite material provided by this invention ensures that the reactants are evenly distributed and in full contact, resulting in a composite material with excellent ablation resistance and mechanical properties, which better meets practical needs.

[0095] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0096] Example 1

[0097] The ablation-resistant high-silica carbon fiber composite material of this embodiment has a structure consisting of alternating water glass fiber composite layers and phenolic fiber composite layers arranged from the outside to the inside.

[0098] The water glass fiber composite layer is composed of the following components in parts by weight:

[0099] 50g of carbon fiber short fibers

[0100] 50g of high silica glass fiber short fibers

[0101] 15g of surfactant

[0102] 3g of sodium fluorosilicate

[0103] 4g of aluminum sulfate

[0104] 4g of antimony trioxide

[0105] 60g of water glass;

[0106] The phenolic fiber composite layer is composed of the following components in parts by weight:

[0107] 50g of carbon fiber short fibers

[0108] 50g of high silica glass fiber short fibers

[0109] 15g of surfactant

[0110] 3g of sodium fluorosilicate

[0111] 4g of aluminum sulfate

[0112] 4g of antimony trioxide

[0113] 13.3g of boron-modified phenolic resin;

[0114] The thickness of both the water glass fiber composite layer and the phenolic fiber composite layer is 3 mm.

[0115] The total number of layers of the water glass fiber composite layer and the phenolic fiber composite layer is 5, and the thickness of the composite material is 15mm.

[0116] The lengths of the T300 carbon fiber short fibers and the high-silica glass fiber short fibers are both 0.5 cm.

[0117] The preparation method of the high-silica carbon fiber composite material consists of the following steps:

[0118] (1) The carbon fiber short fibers and the high-silica glass fiber short fibers were immersed in a 0.1 mol / L sodium hydroxide solution for 2 h, and the immersed carbon fiber short fibers and the high-silica glass fiber short fibers were dried at 80 °C for 24 h; the pretreated carbon fiber short fibers, the high-silica glass fiber short fibers, the surfactant, sodium fluorosilicate, aluminum sulfate and antimony trioxide were mixed to obtain mixed fibers;

[0119] (2) The mixed fibers obtained in step (1) are divided into two equal parts. One part is soaked in a water glass solution for 10 hours to obtain a water glass fiber mixture. The water glass solution is obtained by mixing water glass and water, and the mass ratio of water glass to water is 1:4. The other part is soaked in a boron-modified phenolic resin solution for 10 hours to obtain a phenolic fiber composite layer, thus obtaining a phenolic fiber mixture. The boron-modified phenolic resin solution is obtained by mixing boron-modified phenolic resin and methanol, and the mass ratio of boron-modified phenolic resin to methanol is 1:5.

[0120] (3) Use the water glass fiber mixture obtained in step (2) as the ablation-resistant layer 1; lay the phenolic fiber mixture obtained in step (2) as the support layer 2 on the ablation-resistant layer 1. When laying it, pay attention to pressing it tightly so that the support layer 2 is in close contact with the ablation-resistant layer 1 and cannot be loose; then lay the water glass fiber mixture as the ablation-resistant layer 3; then lay the phenolic fiber mixture as the support layer 4; continue to lay the water glass fiber mixture as the ablation-resistant layer 5 to obtain the preform.

[0121] (4) The preform obtained in step (3) is put into a mold, heated and pressurized in a vulcanizing machine, and demolded to obtain the molded body;

[0122] (5) The molded body obtained in step (4) is cured in an electric thermostatic blower and then naturally cooled to obtain a high silica carbon fiber composite material.

[0123] The temperature changes in steps (4) and (5) are as follows: Figure 1 As shown, the heating and pressurizing process is divided into four stages: the first stage is heating to 100℃ and pressurizing to 0MPa, with a holding time of 20min; the second stage is heating to 130℃ and pressurizing to 2MPa, with a holding time of 20min; the third stage is heating to 170℃ and pressurizing to 5MPa, with a holding time of 30min; the fourth stage is heating to 180℃ and pressurizing to 18MPa, with a holding time of 10min; cooling to 170℃ and holding for 12h for curing, and finally cooling to room temperature.

[0124] The ablation rate was tested using an oxy-acetylene ablation test (heat flux density 2 MW / m², ablation time 60 s), and the overall mass ablation rate was 0.12 g / s. The tensile strength, flexural strength, and compressive strength were measured using a mechanical testing machine to be 15.92 MPa, 12.98 MPa, and 50.91 MPa, respectively.

[0125] Example 2

[0126] The ablation-resistant high-silica carbon fiber composite material of this embodiment has a structure consisting of alternating water glass fiber composite layers and phenolic fiber composite layers arranged from the outside to the inside.

[0127] The water glass fiber composite layer is composed of the following components in parts by weight:

[0128] 50g of carbon fiber short fibers

[0129] 25g of high silica glass fiber short fibers

[0130] 15g of surfactant

[0131] 3g of sodium fluorosilicate

[0132] 4g of aluminum sulfate

[0133] 4g of antimony trioxide

[0134] 60g of water glass;

[0135] The phenolic fiber composite layer is composed of the following components by weight:

[0136] 50g of carbon fiber short fibers

[0137] 25g of high silica glass fiber short fibers

[0138] 15g of surfactant

[0139] 3g of sodium fluorosilicate

[0140] 4g of aluminum sulfate

[0141] 4g of antimony trioxide

[0142] 13.3g of boron-modified phenolic resin;

[0143] The thickness of both the water glass fiber composite layer and the phenolic fiber composite layer is 3 mm.

[0144] The total number of layers of the water glass fiber composite layer and the phenolic fiber composite layer is 5, and the thickness of the composite material is 15mm.

[0145] The lengths of the T300 carbon fiber short fibers and the high-silica glass fiber short fibers are both 0.5 cm.

[0146] The preparation method of the high-silica carbon fiber composite material consists of the following steps:

[0147] (1) The carbon fiber short fibers and the high-silica glass fiber short fibers were immersed in a 0.1 mol / L sodium hydroxide solution for 2 h, and the immersed carbon fiber short fibers and the high-silica glass fiber short fibers were dried at 80 °C for 24 h; the pretreated carbon fiber short fibers, the high-silica glass fiber short fibers, the surfactant, sodium fluorosilicate, aluminum sulfate and antimony trioxide were mixed to obtain mixed fibers;

[0148] (2) The mixed fibers obtained in step (1) are divided into two equal parts. One part is soaked in a water glass solution for 10 hours to obtain a water glass fiber mixture. The water glass solution is obtained by mixing water glass and water, and the mass ratio of water glass to water is 1:4. The other part is soaked in a boron-modified phenolic resin solution for 10 hours to obtain a phenolic fiber composite layer, thus obtaining a phenolic fiber mixture. The boron-modified phenolic resin solution is obtained by mixing boron-modified phenolic resin and methanol, and the mass ratio of boron-modified phenolic resin to methanol is 1:5.

[0149] (3) Use the water glass fiber mixture obtained in step (2) as the ablation-resistant layer 1; lay the phenolic fiber mixture obtained in step (2) as the support layer 2 on the ablation-resistant layer 1. When laying it, pay attention to pressing it tightly so that the support layer 2 is in close contact with the ablation-resistant layer 1 and cannot be loose; then lay the water glass fiber mixture as the ablation-resistant layer 3; then lay the phenolic fiber mixture as the support layer 4; continue to lay the water glass mixture as the ablation-resistant layer 5 to obtain the preform.

[0150] (4) The preform obtained in step (3) is put into a mold, heated and pressurized in a vulcanizing machine, and demolded to obtain the molded body;

[0151] (5) The molded body obtained in step (4) is cured in an electric thermostatic blower and then naturally cooled to obtain a high silica carbon fiber composite material.

[0152] The specific temperature change process in steps (4) and (5) is as follows: The heating and pressurizing process is divided into four stages: the first stage is heated to 100℃, pressurized to 0MPa, and the holding time is 20min; the second stage is heated to 130℃, pressurized to 2MPa, and the holding time is 20min; the third stage is heated to 170℃, pressurized to 5MPa, and the holding time is 30min; the fourth stage is heated to 180℃, pressurized to 18MPa, and the holding time is 10min; the temperature is then cooled to 170℃ and held for 12h for curing, and finally cooled to room temperature.

[0153] The ablation rate was tested using an oxy-acetylene ablation test (heat flux density 2 MW / m², ablation time 60 s), and the overall mass ablation rate was 0.14 g / s. The tensile strength, flexural strength, and compressive strength were measured using a mechanical testing machine to be 33.17 MPa, 22.14 MPa, and 48.67 MPa, respectively.

[0154] Example 3

[0155] The ablation-resistant high-silica carbon fiber composite material of this embodiment has a structure consisting of alternating water glass fiber composite layers and phenolic fiber composite layers arranged from the outside to the inside.

[0156] The water glass fiber composite layer is composed of the following components in parts by weight:

[0157] 75g of carbon fiber short fibers

[0158] 25g of high silica glass fiber short fibers

[0159] 15g of surfactant

[0160] 3g of sodium fluorosilicate

[0161] 4g of aluminum sulfate

[0162] 4g of antimony trioxide

[0163] 60g of water glass;

[0164] The phenolic fiber composite layer is composed of the following components in parts by weight:

[0165] 75g of carbon fiber short fibers

[0166] 25g of high silica glass fiber short fibers

[0167] 15g of surfactant

[0168] 3g of sodium fluorosilicate

[0169] 4g of aluminum sulfate

[0170] 4g of antimony trioxide

[0171] 13.3g of boron-modified phenolic resin;

[0172] The thickness of both the water glass fiber composite layer and the phenolic fiber composite layer is 3 mm.

[0173] The total number of layers of the water glass fiber composite layer and the phenolic fiber composite layer is 5, and the thickness of the composite material is 15mm.

[0174] The lengths of the T300 carbon fiber short fibers and the high-silica glass fiber short fibers are both 0.5 cm.

[0175] The preparation method of the high-silica carbon fiber composite material consists of the following steps:

[0176] (1) The carbon fiber short fibers and the high-silica glass fiber short fibers were immersed in a 0.1 mol / L sodium hydroxide solution for 2 h, and the immersed carbon fiber short fibers and the high-silica glass fiber short fibers were dried at 80 °C for 24 h; the pretreated carbon fiber short fibers, the high-silica glass fiber short fibers, the surfactant, sodium fluorosilicate, aluminum sulfate and antimony trioxide were mixed to obtain mixed fibers;

[0177] (2) The mixed fibers obtained in step (1) are divided into two equal parts. One part is soaked in a water glass solution for 10 hours to obtain a water glass fiber mixture. The water glass solution is obtained by mixing water glass and water, and the mass ratio of water glass to water is 1:4. The other part is soaked in a boron-modified phenolic resin solution for 10 hours to obtain a phenolic fiber composite layer, thus obtaining a phenolic fiber mixture. The boron-modified phenolic resin solution is obtained by mixing boron-modified phenolic resin and methanol, and the mass ratio of boron-modified phenolic resin to methanol is 1:5.

[0178] (3) Use the water glass fiber mixture obtained in step (2) as the ablation-resistant layer 1; lay the phenolic fiber mixture obtained in step (2) as the support layer 2 on the ablation-resistant layer 1. When laying it, pay attention to pressing it tightly so that the support layer 2 is in close contact with the ablation-resistant layer 1 and cannot be loose; then lay the water glass fiber mixture as the ablation-resistant layer 3; then lay the phenolic fiber mixture as the support layer 4; continue to lay the water glass fiber mixture as the ablation-resistant layer 5 to obtain the preform.

[0179] (4) The preform obtained in step (3) is put into a mold, heated and pressurized in a vulcanizing machine, and demolded to obtain the molded body;

[0180] (5) The molded body obtained in step (4) is cured in an electric thermostatic blower and then naturally cooled to obtain a high silica carbon fiber composite material.

[0181] The specific temperature change process in steps (4) and (5) is as follows: The heating and pressurizing process is divided into four stages: the first stage is heated to 100℃, pressurized to 0MPa, and the holding time is 20min; the second stage is heated to 130℃, pressurized to 2MPa, and the holding time is 20min; the third stage is heated to 170℃, pressurized to 5MPa, and the holding time is 30min; the fourth stage is heated to 180℃, pressurized to 18MPa, and the holding time is 10min; the temperature is then cooled to 170℃ and held for 12h for curing, and finally cooled to room temperature.

[0182] Its ablation rate was tested using an oxy-acetylene ablation experiment (heat flux density 2 MW / m). 2The ablation time was 60 s, and the overall mass ablation rate was 0.05 g / s. Its tensile strength was 26.88 MPa, flexural strength was 17.71 MPa, and compressive strength was 55.63 MPa, as measured by a mechanical testing machine.

Claims

1. An ablation-resistant high-silica carbon fiber composite material, comprising water glass fiber composite layers and phenolic fiber composite layers alternately arranged from the outside to the inside; The water glass fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers 50-70 parts of high-silica glass fiber short fibers 15-25 parts of surfactant 3-5 parts of sodium fluorosilicate 4-5 parts aluminum sulfate 4-5 parts of antimony trioxide 60-80 parts of water glass; The phenolic fiber composite layer comprises the following components in parts by weight: 50-75 parts of carbon fiber short fibers 50-70 parts of high-silica glass fiber short fibers 15-25 parts of surfactant 3-5 parts of sodium fluorosilicate 4-5 parts aluminum sulfate 4-5 parts of antimony trioxide 11-17 parts of boron-modified phenolic resin; The surfactant is a surfactant found in carbon fiber composite materials; The preparation method of the ablation-resistant high-silica carbon fiber composite material includes the following steps: (1) Mix carbon fiber short fibers, high silica glass fiber short fibers, surfactants, sodium fluorosilicate, aluminum sulfate and antimony trioxide to obtain mixed fibers; (2) Divide the mixed fibers obtained in step (1) into two equal parts. Mix one part with water glass solution to obtain water glass fiber mixture, and mix the other part with boron modified phenolic resin solution to obtain phenolic fiber mixture. (3) The water glass fiber mixture and phenolic fiber mixture obtained in step (2) are alternately laid flat, with the water glass fiber mixture placed on the outermost layer, and then heated and pressurized to obtain the molded body; (4) The molded body obtained in step (3) is cured to obtain a high-silica carbon fiber composite material; The carbon fiber short fibers and high-silica glass fiber short fibers in step (1) are pretreated before use. The pretreatment includes: Carbon fiber short fibers and high-silica glass fiber short fibers were respectively soaked in sodium hydroxide solution and then dried.

2. The ablation-resistant high-silica carbon fiber composite material according to claim 1, characterized in that, The water glass fiber composite layer comprises the following components in parts by weight: 60-65 parts of carbon fiber short fibers 55-60 parts of high-silica glass fiber short fibers 16-18 parts of surfactant Sodium fluorosilicate 3.5~3.8 parts 4.2-4.4 parts aluminum sulfate Antimony trioxide 4.2~4.4 parts 65-70 parts of water glass; The phenolic fiber composite layer comprises the following components in parts by weight: 60-65 parts of carbon fiber short fibers 55-60 parts of high-silica glass fiber short fibers 16-18 parts of surfactant Sodium fluorosilicate 3.5~3.8 parts 4.2-4.4 parts aluminum sulfate Antimony trioxide 4.2~4.4 parts 13-14 parts of boron-modified phenolic resin.

3. The ablation-resistant high-silica carbon fiber composite material according to claim 1, characterized in that, The thickness of the water glass fiber composite layer and the phenolic fiber composite layer is independently 3~4 mm.

4. The ablation-resistant high-silica carbon fiber composite material according to claim 1, characterized in that, The lengths of the carbon fiber short fibers and the high-silica glass fiber short fibers are independently 0.5~1mm.

5. The method for preparing the ablation-resistant high-silica carbon fiber composite material according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Mix carbon fiber short fibers, high silica glass fiber short fibers, surfactants, sodium fluorosilicate, aluminum sulfate and antimony trioxide to obtain mixed fibers; (2) Divide the mixed fibers obtained in step (1) into two equal parts. Mix one part with water glass solution to obtain water glass fiber mixture, and mix the other part with boron modified phenolic resin solution to obtain phenolic fiber mixture. (3) The water glass fiber mixture and phenolic fiber mixture obtained in step (2) are alternately laid flat, with the water glass fiber mixture placed on the outermost layer, and then heated and pressurized to obtain the molded body; (4) The molded body obtained in step (3) is cured to obtain a high silica carbon fiber composite material.

6. The method for preparing the ablation-resistant high-silica carbon fiber composite material according to claim 5, characterized in that, In step (2), the solvent for the boron-modified phenolic resin solution is methanol, and the mass ratio of the boron-modified phenolic resin to methanol is 1:(5~6).

7. The method for preparing the ablation-resistant high-silica carbon fiber composite material according to claim 5, characterized in that, The heating and pressurizing process in step (3) adopts a programmed temperature and pressure increase, including: the first stage of heating to 100~120℃ and pressurizing to 0~1MPa, and holding the temperature and pressure for 20~30min; the second stage of heating to 130~160℃ and pressurizing to 2~4MPa, and holding the temperature and pressure for 20~40min; the third stage of heating to 170~175℃ and pressurizing to 5~8MPa, and holding the temperature and pressure for 30~40min; the fourth stage of heating to 180~200℃ and pressurizing to 18~20MPa, and holding the temperature and pressure for 10~20min.

8. The method for preparing the ablation-resistant high-silica carbon fiber composite material according to claim 5, characterized in that, The curing temperature in step (4) is 170~180℃, and the curing time is 12~13h.

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