A high-strength silicon carbide fiber felt laminate with adjustable electrical properties and a method of making the same

Abstract

This invention discloses a high-strength silicon carbide fiber felt laminate with adjustable electrical properties and its preparation method. Silicon carbide fibers are subjected to plasma surface treatment, then added to a nano-dispersion liquid to obtain a fiber suspension. The fiber suspension is dehydrated, shaped, dried, and cured to obtain silicon carbide fiber felt. The silicon carbide fiber felt is impregnated or sprayed with a resin adhesive and pre-dried to obtain a silicon carbide fiber felt prepreg. The silicon carbide fiber felt prepreg is cut, layered, and then hot-pressed to obtain the silicon carbide fiber felt laminate. The silicon carbide fiber felt laminate provided by this invention has the characteristics of isotropy, high mechanical strength, non-delamination, adjustable electrical properties, and a tracking index ≥600V, and can be widely used in aviation, aerospace, new energy vehicles, and other fields.

Description

Technical Field

[0001] This invention relates to a high-strength silicon carbide fiber felt laminate with adjustable electrical properties and its preparation method, belonging to the technical field of silicon carbide fiber felt laminate preparation. Background Technology

[0002] Chinese patent CN109423002A points out that existing fiber laminates mainly use carbon fiber felt as raw material, but the fiber bundles in the carbon fiber felt are loose and disordered, with poor mutual restraint. Furthermore, while there has been considerable research on carbon fiber in recent years, research on laminates prepared using silicon carbide fiber as raw material is extremely limited.

[0003] Currently, the main methods for preparing silicon carbide fiber mats are electrospinning and needle punching. Electrospinning is extremely slow and has low yield; needle punching is difficult due to the high modulus and low cohesion of silicon carbide fibers, and the fibers are also brittle, causing significant damage during the needle punching process.

[0004] Wet-laid nonwoven fabric technology uses water as a medium to uniformly suspend short fibers. The water flow then causes the fibers to deposit onto a permeable curtain or porous roller, forming a wet web. The International Nonwovens Association defines it as: "A paper-like nonwoven fabric produced by the deposition of fibers suspended in a water tank, followed by a series of processing steps including web fixing." In other words, wet-laid nonwoven fabric is a nonwoven fabric obtained by dehydrating a fiber web of water, fibers, and chemical auxiliaries in a specialized forming device, followed by web fixing using physical and chemical methods.

[0005] Wet-laid nonwoven silicon carbide fiber mat laminates have the characteristics of isotropy, high mechanical strength, non-delamination, and adjustable electrical properties, and can be widely used in aviation, aerospace, new energy vehicle and other fields.

[0006] Patent (CN 105386237 A) discloses the use of polycarbosilane infusible fibers as a precursor, which are loosened by airflow and mixed into pulp. After wet deposition and drying, the fibers are sintered in a high-temperature furnace to obtain silicon carbide fiber felt. Specifically, the polycarbosilane infusible fiber felt is placed in a high-temperature furnace and heated to 1000-1300℃ at a rate of 15-240℃ / h under high-purity nitrogen protection, and held at that temperature for 1-1.5h to obtain silicon carbide fiber felt.

[0007] It is evident that the existing silicon carbide fiber felt preparation technology is relatively complex. It uses polycarbosilane as a precursor for preparation, followed by sintering after molding. The preparation time is long, the equipment requirements are high, the single preparation volume is small, the output is low, the basis weight of the fiber felt cannot be accurately controlled, continuous production is difficult, high temperature and high purity nitrogen protection are required, and the energy consumption is high. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties. The preparation method of this invention is simple, allows for continuous production, and provides freely controllable product specifications.

[0009] The second objective of this invention is to provide a silicon carbide fiber felt laminate prepared by the above-described method. The silicon carbide fiber felt laminate provided by this invention possesses isotropic properties, high mechanical strength, non-delamination, adjustable electrical properties, and a tracking resistance index ≥600V, making it widely applicable in fields such as aviation, aerospace, and new energy vehicles.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention discloses a method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties. The method involves plasma surface treatment of silicon carbide fibers, followed by addition to a nano-dispersion liquid to obtain a fiber suspension. The fiber suspension is then dehydrated, shaped, dried, and cured to obtain silicon carbide fiber felt. The silicon carbide fiber felt is impregnated or sprayed with a resin adhesive and pre-baked to obtain a silicon carbide fiber felt prepreg. The silicon carbide fiber felt prepreg is cut, layered, and then hot-pressed to obtain the silicon carbide fiber felt laminate.

[0012] The nano-dispersion is composed of the following components by weight: 0.5-25 parts surfactant, 0.2-15 parts fumed silica, 0.1-10 parts thickener, 0.1-0.5 parts defoamer, 0.5-10 parts softener, and 39.5-98.6 parts water.

[0013] The preparation method of this invention first involves surface treatment of short-cut fibers using low-temperature plasma. This only alters the physical and chemical properties of the material surface, introducing hydrophilic groups such as carboxyl, hydroxyl, and carbonyl groups onto the surface of silicon carbide fibers. This improves the wettability of the silicon carbide fiber surface, which is beneficial for fiber dispersion in nano-dispersion liquid. Compared with conventional oxidation methods, the surface etching effect is more significant, which can reduce the rigidity of silicon carbide fibers to a certain extent, improve fiber flexibility, and reduce flocculation problems during dispersion to a certain extent. It also helps to increase the contact area between the fiber and the resin material, improve the bonding strength, and enhance the performance of the composite material. In addition, the amount of hydrophilic groups introduced by plasma treatment is not significantly different.

[0014] The silicon carbide fibers are then dispersed in a nano-dispersion liquid to ensure uniform dispersion. This invention incorporates fumed silica powder into the dispersion liquid, which further modifies the surface, promotes the dispersibility of silicon carbide in water, and provides skeletal support. Firstly, the fumed silica forms a mesh structure during the composite felt forming process. This structure provides a robust support framework, preventing deformation and breakage of the silicon carbide fibers during forming. This skeletal support makes the overall structure of the composite felt more stable, increasing its mechanical strength and tensile properties. Furthermore, this structure helps the silicon carbide fiber felt maintain a certain thickness and shape, making it more suitable for various applications. Secondly, fumed silica can form a silica coating layer on the surface of silicon carbide fibers, thereby modifying the fiber surface. This surface modification can improve the chemical stability and antioxidant properties of silicon carbide fibers, extending their service life. Simultaneously, this coating layer can reduce the friction between fibers, improving their flexibility and wear resistance. Furthermore, the surface modification of silica can also affect the bonding performance between the fibers and the matrix, enhancing the overall stability of the fiber composite felt. Meanwhile, the surfactants in the nano-dispersion can improve the viscosity and flowability of the dispersion, promoting the wetting and dispersion of the fiber material. They possess the properties of dispersion, wetting, and reducing surface tension, forming a thin film between the fiber material and the liquid, improving the compatibility between the fiber material and the mixture. Thickeners also help to change the viscosity and thixotropic properties of the dispersion, preventing fiber dispersion and sedimentation. Softeners can improve the antistatic properties and increase the hydrophilicity of the fibers, improving their softness. Under the synergistic effect of the above, the prepared silicon carbide fiber felt has a uniform mass distribution, good appearance, and high strength.

[0015] Finally, the silicon carbide fiber felt is impregnated or sprayed with resin adhesive and pre-dried to obtain silicon carbide fiber felt prepreg. The silicon carbide fiber felt prepreg is then cut, stacked, and hot-pressed to obtain silicon carbide fiber felt laminate. The resulting silicon carbide fiber felt laminate is isotropic, has high mechanical strength, does not delaminate, and has adjustable electrical properties.

[0016] Further preferably, the nano-dispersion is composed of the following components by weight: 15-20 parts surfactant, 1-5 parts fumed silica, 4-10 parts thickener, 0.1-0.5 parts defoamer, 5-10 parts softener, and 39.5-98.6 parts water.

[0017] As a preferred embodiment, the length of the silicon carbide fiber is 4–15 mm. Controlling the length of the silicon carbide fiber in this invention is beneficial for subsequent dispersion. In this invention, the silicon carbide fiber is a short-cut carbon fiber obtained by cutting long silicon carbide fibers using a fiber cutting machine.

[0018] As a preferred embodiment, the conditions for the plasma surface hydrophilic modification treatment are: time of 5–90 min, power of 600–900 W, and pressure of 0.1–0.2 MPa. Higher power and pressure during the plasma surface hydrophilic treatment result in a more pronounced surface etching effect on the silicon carbide fibers. Controlling these conditions within the aforementioned range ensures the introduction of functional groups into the silicon carbide fibers, improving hydrophilicity, while avoiding a decrease in mechanical properties.

[0019] As a preferred embodiment, the preparation process of the nano-dispersion is as follows: surfactant, fumed silica, thickener, defoamer, and softener are added to water, and the pH is adjusted to 2-12, preferably 3-6, followed by sand milling and pulping. In this invention, the pH can be adjusted according to the fiber dispersion rate; the faster the dispersion rate, the better, as a suitable pH value can accelerate the dispersion process.

[0020] As a preferred embodiment, the softener is a polyether-modified silicone oil and / or a hydrophilic amino silicone oil.

[0021] As a preferred embodiment, the surfactant is at least one selected from sodium hexametaphosphate, fatty alcohol polyoxyethylene ether, fatty amine polyoxyethylene ether, alkyl ammonium salt, fatty alcohol and ethylene oxide condensate, polyethylene glycol, polyoxyethylene sorbitan monostearate, polyvinylpyrrolidone, and cetearyl alcohol polyoxyethylene ether; and the thickener is at least one selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyethylene oxide.

[0022] As a preferred embodiment, the defoamer is at least one selected from butyl phosphate, silicone, alkyl polyether, and polyether siloxane. Examples of butyl phosphate used in this invention include tributyl phosphate, silicone such as Defeng 2854, alkyl polyether such as Xinwancheng S-717, and polyether siloxane such as Tego 902W.

[0023] As a preferred embodiment, the viscosity of the fiber suspension is 5–400 mPa·s; the air content is 2–20%. The viscosity of the nano-dispersion can affect the stability of silicon carbide fibers in the slurry, while the air content affects the unit area weight during fiber mat forming. More preferably, the viscosity is 185–300 mPa·s, and the air content is 2–5%.

[0024] As a preferred embodiment, the sand milling and pulping time is 20–180 min.

[0025] In actual operation, the fiber suspension is sent to the grid for dehydration and molding.

[0026] As a preferred embodiment, the felt obtained after dehydration and molding is mixed with an adhesive and then dried and cured. The amount of adhesive added is 5-15% of the mass of the felt.

[0027] As a further preferred embodiment, the adhesive is selected from one of acrylic resin, polyurethane, silicone resin, phenolic resin, and epoxy resin. The adhesive is added by dip coating.

[0028] As a preferred embodiment, the resin adhesive comprises, by weight percentage, the following: 10-25 parts high-temperature resistant resin, 10-25 parts modified phenolic resin, 20-40 parts resin curing agent, 5-30 parts inorganic filler, 0.2-1.8 parts coupling agent, and 50-100 parts solvent.

[0029] More preferably, the high-temperature resistant resin is selected from at least one of amino resin, silicone resin, bisphenol A type epoxy resin, cyanuric acid epoxy resin, pyromellitic polyimide, bismaleimide resin, phenolic cyanate ester resin, bisphenol A type cyanate ester resin, polytetrafluoroethylene, polyphenylene oxide, and polyetheretherketone resin.

[0030] More preferably, the modified phenolic resin is selected from at least one of polyamide-modified phenolic resin, dicyandiamide-modified phenolic resin, organosilicon-modified phenolic resin, boron-modified phenolic resin, diphenyl ether formaldehyde resin, and modified neophenolic resin.

[0031] More preferably, the resin curing agent is selected from at least one of m-phenylenediamine, m-phenylenediamine, vinyltriamine, MDA-60, trimethylhexamethylenediamine, N,N-dimethylbenzylamine, triethylenetetramine, low molecular weight polyamide, trimellitic anhydride, and dicyandiamide.

[0032] More preferably, the inorganic filler is selected from at least one of titanium dioxide, talc, magnesium hydroxide, kaolin, and alumina.

[0033] More preferably, the coupling agent is selected from at least one of trichlorovinylsilane, triethoxyvinylsilane, trichloropropylene silane, tetrabutyl titanate, and triisostearoyl titanate isopropyl triisostearoyl titanate.

[0034] More preferably, the solvent is selected from at least one of toluene, xylene, ethanol, propylene glycol, acetone, ethyl acetate, and benzyl alcohol.

[0035] In a further preferred embodiment, high-temperature resistant resin and modified phenolic resin are added to a dispersion tank, stirred at 60-100℃ for 0.5-2 hours, inorganic filler, coupling agent, curing agent and solvent are added, and stirring is continued for 0.3-1.5 hours. The resin adhesive is obtained by removing air bubbles under vacuum and at a temperature of 55-65℃.

[0036] As a preferred embodiment, the pre-drying temperature is 60-160℃. In actual operation, the silicon carbide fiber felt is pre-dried through the drying tunnel of a horizontal gluing machine to obtain silicon carbide fiber felt prepreg.

[0037] As a preferred embodiment, the silicon carbide fiber felt prepreg contains 30%-60% silicon carbide fiber felt by mass.

[0038] As a preferred embodiment, the hot pressing temperature is 120-200℃, the hot pressing time is 0.5-30h, and the pressure is 200-500Kpa.

[0039] In a further preferred embodiment, the hot-pressing process involves first hot-pressing at 95-100℃ for 20-40 minutes, then raising the temperature to 120-140℃ and hot-pressing for 0.5-2 hours, controlling the hot-pressing pressure at 250-300 kPa. This preferred hot-pressing method yields the best final performance.

[0040] In actual operation, the silicon carbide fiber felt prepreg is cut to the required size according to the process and then stacked one or more layers or placed at 0 / 90° on a stainless steel plate coated with a release agent, and then sent into a hot press for hot pressing.

[0041] As a preferred embodiment, the thickness of the silicon carbide fiber felt laminate is 0.5-200 mm.

[0042] The present invention also provides a silicon carbide fiber felt laminate prepared by the above preparation method.

[0043] The silicon carbide fiber felt product prepared by this invention has the following advantages:

[0044] Using silicon carbide fiber felt as raw material, it has stable physical and chemical properties, and the fiber is resistant to temperature up to 1300℃. The laminate prepared with it has stable performance at high temperatures, and at the same time has the advantage of freely adjustable electrical properties, resulting in better application performance.

[0045] This invention uses silicon carbide short-cut fibers to directly obtain silicon carbide fiber felt products through wet felting technology, and the raw materials for silicon carbide fiber felt can be obtained in batches. Attached Figure Description

[0046] Figure 1 This is a photograph of the silicon carbide fiber felt product prepared in Example 1.

[0047] Figure 2 A physical image of the silicon carbide fiber felt product prepared for Comparative Example 1.

[0048] Figure 3This is a photograph of the silicon carbide fiber felt laminate prepared in Example 1. Detailed Implementation

[0049] Example 1

[0050] 1. Preparation of silicon carbide fiber felt:

[0051] 1) Cut the silicon carbide fiber into 4mm short fibers using a fiber cutter;

[0052] 2) The short-cut fibers obtained in step 1) are surface-treated for 30 minutes using a low-temperature plasma surface treatment machine with a power of 800W and a working gas pressure of 0.101Mpa.

[0053] 3) Add 74.9g of water to the dispersion tank, then add 10g of sodium hexametaphosphate, 5g of polyethylene glycol, 1g of hydrophilic fumed silica, 4g of carboxymethyl cellulose, 0.1g of GTE 902w and 5g of polyether silicone modified silicone oil in sequence. Adjust the pH value to 3-6, and after sand milling for 1 hour, the nano-dispersion is ready.

[0054] 4) Weigh a certain amount of silicon carbide fiber from step 2) and add it to the nano-dispersion prepared in step 3). Stir and disperse the mixture in a dispersion tank to prepare a uniform silicon carbide fiber suspension with a viscosity of 185 mPa·s and an air content of 5%.

[0055] 5) The silicon carbide fiber suspension prepared in step 4) is transported to a grid for dehydration and molding. Then, 4% acrylic emulsion adhesive is added and the mixture is dried and cured in a forced-air oven. The product is then cut to obtain the silicon carbide fiber felt.

[0056] 2. High-strength, tracking-resistant resin adhesive: Amino resin and polyamide-modified phenolic resin are added to a dispersion tank at room temperature. After stirring at 60°C for 0.5 hours, titanium dioxide, trichlorovinylsilane, MDA-60 (purchased from Tongchuang Chemical), and toluene are added. Stirring continues for 0.5 hours. Air bubbles are removed under vacuum at 60°C to obtain the target resin adhesive. The composition includes 15 parts by weight of amino resin, 15 parts by weight of polyamide-modified phenolic resin, 35 parts by weight of MDA-60, 14 parts by weight of titanium dioxide, 8 parts by weight of talc, 0.4 parts by weight of trichlorovinylsilane, and 60 parts by weight of toluene.

[0057] 3. Preparation of silicon carbide felt prepreg: The wet silicon carbide fiber felt obtained in step 1 is kept at a temperature of 60°C and impregnated or sprayed with the resin adhesive described in step 2 using a horizontal gluing machine to obtain silicon carbide fiber felt prepreg.

[0058] 4. Preparation of silicon carbide fiber felt laminate: The silicon carbide fiber felt prepreg is cut into the required size according to the process and then layered one or more layers. The composite material is then vacuumed for 30 minutes, placed on a stainless steel plate coated with a release agent, and sent into a hot press. The pressure is set to 300 kPa, the temperature is 100℃ for 30 minutes, and the temperature is 140℃ for 60 minutes to form the laminate. The thickness of the laminate after forming is 0.5-200 mm, and the silicon carbide fiber felt composite laminate material is obtained.

[0059] Example 2

[0060] 1. Preparation of silicon carbide fiber felt:

[0061] 1) Cut the silicon carbide fiber into 12mm short fibers using a fiber cutter;

[0062] 2) The short-cut fibers obtained in step 1) were surface treated for 40 minutes using a low-temperature plasma surface treatment machine with a power of 800W and a working pressure of 0.101Mpa.

[0063] 3) Add 69.2g of water to the dispersion tank, then add 15g of sodium hexametaphosphate, 5g of polyvinylpyrrolidone, 1.5g of hydrophilic fumed silica, 4g of carboxypropyl methylcellulose, 0.3g of tributyl phosphate and 5g of polyether silicone modified silicone oil in sequence. Adjust the pH value to 10-12, and after sand milling for 1.5h, the nano-dispersion is ready.

[0064] 4) Weigh a certain amount of silicon carbide fiber from step 2) and add it to the nano-dispersion prepared in step 3). Stir and disperse the mixture in a dispersion tank to prepare a uniform silicon carbide fiber suspension with a viscosity of 200 mPa·s and an air content of 5%.

[0065] 5) The silicon carbide fiber suspension prepared in step 4) is transported to a grid for dehydration and molding. Then, 5% phenolic resin adhesive is added and the mixture is dried and cured in a forced-air oven. The product is then cut to obtain the silicon carbide fiber felt.

[0066] 2. High-strength, tracking-resistant resin adhesive: Epoxy resin and polyamide-modified phenolic resin are added to a dispersion tank at room temperature. After stirring at 60°C for 0.5 hours, titanium dioxide, trichlorovinylsilane, N,N-dimethylbenzylamine, and toluene are added, and stirring continues for another 0.5 hours. Air bubbles are removed under vacuum at 60°C to obtain the target resin adhesive. The composition includes 10 parts by weight of bisphenol A epoxy resin, 20 parts by weight of polyamide-modified phenolic resin, 32 parts by weight of N,N-dimethylbenzylamine, 10 parts by weight of titanium dioxide, 6 parts by weight of talc, 8 parts by weight of alumina powder, 0.5 parts by weight of trichlorovinylsilane, and 50 parts by weight of toluene.

[0067] 3. Preparation of silicon carbide felt prepreg: The wet silicon carbide fiber felt obtained in step 1 is kept at a temperature of 60°C and impregnated or sprayed with the resin adhesive described in step 2 using a horizontal gluing machine to obtain silicon carbide fiber felt prepreg.

[0068] 4. Preparation of silicon carbide fiber felt laminate: The prepared silicon carbide fiber felt prepreg is cut into the required size according to the process and placed in layers at 0 / 90°. Then, the composite material is vacuumed for 20 minutes and placed on a stainless steel plate coated with a release agent. It is then sent into a hot press with a pressure of 250 kPa, a temperature of 95℃ for 30 minutes, and a temperature of 120℃ for 60 minutes to form the laminate. The thickness of the laminate after forming is 0.5-200 mm, thus obtaining the silicon carbide fiber felt composite laminate material.

[0069] Comparative Example 1

[0070] The only difference between this comparative example and Example 1 is that plasma surface treatment was not performed; all other conditions and steps were the same. The prepared silicon carbide fiber suspension was transported to a grid for dehydration and molding, followed by the addition of an adhesive and drying and curing in a forced-air oven. The surface of the resulting fiber felt product was as shown in the image. Figure 2 The fiber agglomeration shown indicates that the product quality is substandard.

[0071] Comparative Example 2

[0072] Other conditions were the same as in Example 1, except that the silicon carbide fibers were not subjected to low-temperature plasma treatment. Instead, the obtained chopped silicon carbide fibers were added to a mixed aqueous solution of hydrofluoric acid and phosphoric acid in a ratio of 5:2, heated to 120°C, and kept at that temperature for 2 hours. After removal, the fibers were washed four times with alcohol and then dried in a 60°C oven for 3 hours before being added to the nano-dispersion solution. During the washing and drying process, the acid-treated modified silicon carbide fibers tended to clump together, increasing the difficulty of fiber dispersion and manufacturing costs. Acid washing also caused damage to the fiber surface and reduced strength, resulting in uneven agglomeration on the surface of the final felt.

[0073] Comparative Example 3

[0074] The only difference between this comparative example and Example 1 is that hydrophilic fumed silica was not added to the nano-dispersion, resulting in the tendency for the nano-dispersion to form bundles.

[0075] The silicon carbide fiber felt laminates obtained in the examples and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0076] Table 1

[0077]

Claims

1. A method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties, characterized in that: After plasma surface hydrophilic modification treatment of silicon carbide fibers, they are added to a nano-dispersion liquid to obtain a fiber suspension. The fiber suspension is dehydrated, shaped, dried, and cured to obtain silicon carbide fiber felt. The silicon carbide fiber felt is impregnated or sprayed with resin adhesive and pre-dried to obtain silicon carbide fiber felt prepreg. The silicon carbide fiber felt prepreg is cut and stacked, and then hot-pressed to obtain silicon carbide fiber felt laminate. The length of the silicon carbide fiber is 4~15mm; The conditions for the plasma surface hydrophilic modification treatment are: time 5~90 ​​min, power 600~900 W, and pressure 0.1~0.2 MPa. The nano-dispersion is composed of the following components by weight: 0.5-25 parts surfactant, 0.2-15 parts fumed silica, 0.1-10 parts thickener, 0.1-0.5 parts defoamer, 0.5-10 parts softener, and 39.5-98.6 parts water; the fumed silica is hydrophilic fumed silica.

2. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 1, characterized in that: The preparation process of the nano-dispersion is as follows: after adding surfactant, fumed silica, thickener, defoamer and softener to water, the pH is adjusted to 2~12 and then sand milling is performed; the sand milling time is 20~180min.

3. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 1 or 2, characterized in that: The softener is a polyether-modified silicone oil and / or a hydrophilic amino silicone oil; The surfactant is at least one of sodium hexametaphosphate, fatty alcohol polyoxyethylene ether, fatty amine polyoxyethylene ether, alkyl ammonium salt, polyethylene glycol, polyoxyethylene sorbitan monostearate, and polyvinylpyrrolidone; the thickener is at least one of carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyethylene oxide. The defoamer is at least one of butyl phosphate, organosilicon, and alkyl polyether.

4. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 1, characterized in that: The viscosity of the fiber suspension is 5~400 mPa·s; the air content is 2~20%; After dehydration and molding, the resulting felt is mixed with an adhesive and then dried and cured. The amount of adhesive added is 5-15% of the mass of the felt. The adhesive is selected from one of acrylic resin, polyurethane, silicone resin, phenolic resin, and epoxy resin.

5. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 1, characterized in that: The resin adhesive, by weight, comprises the following components: 10-25 parts high-temperature resistant resin, 10-25 parts modified phenolic resin, 20-40 parts resin curing agent, 5-30 parts inorganic filler, 0.2-1.8 parts coupling agent, and 50-100 parts solvent.

6. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 5, characterized in that: The high-temperature resistant resin is selected from at least one of amino resin, silicone resin, bisphenol A epoxy resin, cyanuric acid epoxy resin, pyromellitic polyimide, bismaleimide resin, phenolic cyanate ester resin, bisphenol A cyanate ester resin, polytetrafluoroethylene, polyphenylene oxide, and polyetheretherketone resin. The modified phenolic resin is selected from at least one of polyamide-modified phenolic resin, dicyandiamide-modified phenolic resin, organosilicon-modified phenolic resin, boron-modified phenolic resin, and diphenyl ether formaldehyde resin. The resin curing agent is selected from at least one of m-phenylenediamine, m-phenylenediamine, vinyltriamine, MDA-60, trimethylhexamethylenediamine, N,N-dimethylbenzylamine, triethylenetetramine, low molecular weight polyamide, trimellitic anhydride, and dicyandiamide; The inorganic filler is selected from at least one of titanium dioxide, talc, magnesium hydroxide, kaolin, and alumina; The coupling agent is selected from at least one of trichlorovinylsilane, triethoxyvinylsilane, trichloropropylene silane, tetrabutyl titanate, and triisostearoyl titanate isopropyl triisostearoyl titanate; The solvent is selected from at least one of toluene, xylene, ethanol, propylene glycol, acetone, ethyl acetate, and benzyl alcohol.

7. A method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 1 or 5, characterized in that: The preparation process of the resin adhesive is as follows: high-temperature resistant resin and modified phenolic resin are added to a dispersion tank, stirred at 60-100℃ for 0.5-2 hours, inorganic filler, coupling agent, curing agent and solvent are added, and stirring is continued for 0.3-1.5 hours. The resin adhesive is obtained by removing air bubbles under vacuum and at a temperature of 55-65℃.

8. The method for preparing a high-strength silicon carbide fiber felt laminate with adjustable electrical properties according to claim 7, characterized in that: The pre-baking temperature is 70-160℃; In the silicon carbide fiber felt prepreg, the mass fraction of silicon carbide fiber felt is 30%-60%; The hot pressing temperature is 120-200℃, the hot pressing time is 0.5-30h, and the pressure is 200-500kPa; The thickness of the silicon carbide fiber felt laminate is 0.5-200mm.

9. The silicon carbide fiber felt laminate prepared by the preparation method according to any one of claims 1-8.

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