SiCf / MoS2 / SiC high-temperature structure wave-absorbing composite material and preparation method thereof

Abstract

The invention belongs to the technical field of wave-absorbing materials, and relates to a SiCf / MoS2 / SiC high-temperature structure wave-absorbing composite material and a preparation method thereof. The preparation method comprises the following steps: firstly, completely immersing a treated SiC fiber preform into a MoS2 reaction solution, and uniformly covering the SiC fiber preform with the MoS2 reaction solution after immersing for a specified time; then, placing the soaked SiC fiber preform in a reaction container for reaction to obtain a SiC fiber preform with a MoS2 interface layer; and finally, performing gas-phase reaction on the SiC fiber preform with the MoS2 interface layer by using a chemical gas-phase infiltration method to prepare a SiC matrix, thereby completing the preparation of the SiCf / MoS2 / SiC high-temperature structure wave-absorbing composite material. The preparation method provided by the invention is simple in preparation process, controllable in process parameters, high in feasibility and good in repeatability.

Description

Technical Field

[0001] The present invention belongs to the technical field of wave absorbing materials, and relates to a high temperature wave absorbing composite material, and specifically to a SiC f / MoS 2 / SiC high temperature structural wave absorbing composite material and preparation method thereof. Background Art

[0002] With the development of science and technology, high temperature resistant structural absorbing materials have gradually become one of the important factors restricting the development of equipment. Among high temperature resistant structural absorbing materials, continuous fiber reinforced ceramic matrix composites have the most advantages. They have the advantages of high specific strength, high specific modulus, high toughness, etc. Through the design of the dielectric properties of the matrix and the reinforcement, high-performance high temperature absorbing materials can be prepared. At present, continuous fiber reinforced SiC-based composite materials mainly include SiC f / SiC (SiC fiber reinforced) and C f / SiC (C fiber reinforced). f / SiC can maintain its strength, modulus and other mechanical properties at over 2000℃ in an inert environment. However, C fiber itself has high conductivity, strong reflection of electromagnetic waves, and will be oxidized in an oxidizing atmosphere above 400℃, resulting in reduced material performance or even failure, thus limiting the application of C f / SiC is more widely used. Compared with C fiber, SiC fiber has better oxidation resistance and excellent compatibility with SiC ceramic matrix, so SiC f / SiC composite materials are an excellent combination of high temperature resistance and high thermal conductivity.

[0003] At present, in order to control SiC f The dielectric properties of SiC / SiC absorbing composite materials are mainly improved by adding absorbents to SiC or preparing an interface layer on the surface of SiC fibers. The existing Chinese patent document (publication number CN105237021A, announcement date: January 13, 2016) discloses a method for preparing a ceramic matrix composite material by modifying the interface of a SiC nanowire-modified ceramic matrix composite material. The method first immerses a porous fiber preform in a catalyst solution, and then in a CVD furnace, trichloromethyl alkane is used as a silicon source, argon is used as a diluent, and hydrogen is used as a carrier gas to deposit SiC nanowires in situ. After that, the fiber preform containing SiC nanowires is placed in a CVD furnace, trichloromethyl alkane is used as a silicon source, argon is used as a diluent, and a CVI process is used to prepare a SiC matrix, and a dense SiC nanowire-modified ceramic matrix composite material can be obtained. In this method, the introduction of SiC nanowires can improve the high-temperature oxidation resistance and mechanical properties of the composite material, but the SiC nanowires are prone to form a strong interface bond with the SiC fiber and the matrix, resulting in brittle failure of the composite material.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a SiC f / MoS 2 / SiC high temperature structural wave absorbing composite material and preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] This SiC f / MoS 2 The method for preparing a MoS / SiC high temperature structural wave absorbing composite material comprises: firstly, completely immersing a treated SiC fiber preform into a MoS 2 After soaking in the reaction solution for a specified time, the MoS 2 The reaction liquid is evenly covered on the SiC fiber preform; then, the soaked SiC fiber preform is placed in a reaction container for reaction to obtain a MoS 2 Finally, chemical vapor infiltration was used to form a SiC fiber preform with MoS 2 The SiC fiber preform of the interface layer undergoes a gas phase reaction to prepare a SiC matrix, thereby completing the SiC f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0008] Furthermore, the above preparation method specifically comprises the following steps:

[0009] Step 1, treatment of the SiC fiber preform: after ultrasonic cleaning the SiC fiber preform with anhydrous ethanol, the preform is placed in an oven for drying to obtain the treated SiC fiber preform;

[0010] Step 2: MoS 2 Preparation of the reaction solution: Mix the sulfur source and the molybdenum source in a molar ratio of 1:2, add deionized water, heat and stir until the mixture is uniform to obtain MoS 2 Reaction solution;

[0011] Step 3: MoS 2 Preparation of interface layer:

[0012] The treated SiC fiber preform is completely immersed in the MoS 2 The reaction solution was immersed for 0.5 to 1 h to allow the MoS 2The reaction liquid fully covers the SiC fiber preform; the soaked SiC fiber preform is placed in a reaction container and reacted at a temperature of 200 to 250°C for 20 to 24 hours. After the reaction is completed, after the temperature of the reactor drops to room temperature, take out the MoS 2 SiC fiber preform of the interface layer;

[0013] Step 4: Preparation of SiC substrate: 2 The SiC fiber preform of the interface layer is placed in a chemical vapor deposition furnace for gas phase reaction to prepare the SiC matrix, that is, the SiC f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0014] It should be noted that the order of step 1 and step 2 is not particularly limited. In principle, as long as the MoS 2 Complete the SiC fiber preform treatment before the interface layer, MoS 2 The reaction solution can be prepared, and the two steps can be carried out successively or simultaneously.

[0015] Specifically, the step 1 is as follows:

[0016] Step 1.1, immersing the SiC fiber preform in anhydrous ethanol, and ultrasonically vibrating for 10 to 30 minutes, and taking out the SiC fiber preform after the vibration ends;

[0017] Step 1.2, placing the SiC fiber preform in an oven at 80-120° C. for 15-30 minutes and then taking it out to obtain a SiC fiber preform after debonding.

[0018] Specifically, the step 2 is as follows:

[0019] Step 2.1, C 2 H 5 NS is a sulfur source, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is a molybdenum source, mixed with molybdenum and sulfur in a molar ratio of 1:2, and 120-250 ml of deionized water is added to form solution A;

[0020] Step 2.2, place the vessel containing the solution A on a magnetic stirrer, adjust the temperature to 40-50°C and the speed to 400-600 r / min, and heat and stir for 30-50 min to obtain MoS 2 Reaction liquid.

[0021] Specifically, the specified time in step 3 is 0.5 to 1 hour.

[0022] Specifically, the gas phase reaction in step 4 is specifically:

[0023] The chemical vapor deposition furnace is heated from room temperature to 900-1100° C. at a heating rate of 5-10° C. / min, the furnace pressure of the chemical vapor deposition furnace is maintained in the range of 6-8 kPa, and the SiC substrate is prepared by deposition for 15-30 hours;

[0024] After the deposition is completed, the SiC f / MoS 2 / SiC high temperature structural absorbing composite material.

[0025] Further, in step 4, the gas phase reaction is carried out with H 2 As carrier gas and H 2 The flow rate is 800-900 sccm; CH 3 SiCl 3 As the precursor, CO 2 is the reaction gas and CO 2 The flow rate is 100-600 sccm.

[0026] Specifically, the SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fibers in the SiC fiber braid is 10-12 μm, the fiber bundle ratio is 1:1000, and the electrical conductivity is 3-6 S / m.

[0027] In addition, the present invention also provides a SiC f / MoS 2 / SiC high temperature structural absorbing composite material, which is prepared by using the preparation method described in part or in whole above, and the high temperature structural absorbing composite material comprises: 32-50wt% (weight percentage) SiC fiber, 50-68wt% (weight percentage) SiC matrix and MoS 2 Interface layer (its content is not included in the total weight).

[0028] Furthermore, the MoS 2 The thickness of the interface layer is 100 to 150 nm.

[0029] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0030] 1) SiC prepared by the present invention f / MoS 2 / SiC high temperature structural microwave absorbing composite material, due to MoS 2 It is a layered compound with weak interlayer bonding and self-lubricating properties. fThe interface layer of the MoS / SiC composite material can form a weak interface layer between the composite fiber and the matrix, thereby improving the fracture toughness of the composite material. 2 As a semiconductor compound, MoS has moderate conductivity and will not cause strong reflection of electromagnetic waves. 2 The oxidation resistance is better than that of the carbon interface layer, the oxidation start temperature is higher, and the overall oxidation resistance of the composite material can be improved.

[0031] 2) The present invention introduces CO during the preparation process of the SiC matrix 2 The free carbon content in the matrix can be adjusted to effectively adjust the dielectric properties of the absorbing composite material, so that it has better absorbing performance. This method can not only ensure that the absorbing composite material has a high bending strength, but also effectively adjust the dielectric constant and dielectric loss of the absorbing composite material.

[0032] In summary, the preparation method provided by the present invention has simple preparation process, controllable process parameters, strong feasibility and good repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A SiC provided by the present invention f / MoS 2 Flow chart of the preparation method of / SiC high temperature structural absorbing composite material. DETAILED DESCRIPTION

[0036] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0038] Example 1

[0039] See also Figure 1 This embodiment provides a SiC f / MoS2 / SiC high temperature structure absorbing composite material preparation method, the specific preparation process is as follows:

[0040] Step 1: Processing of SiC fiber preform:

[0041] The 2.5-dimensional SiC fiber braid is immersed in anhydrous ethanol and subjected to ultrasonic vibration for 10 minutes. After the vibration, the SiC fiber braid is taken out, and the SiC fiber braid is placed in an oven at 80°C for 30 minutes and then taken out to obtain a SiC fiber preform after degumming treatment, which is used as a substrate for standby use. The SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fiber in the SiC fiber braid is 10 μm, the fiber bundle ratio is 1:1000, and the conductivity is 3S / m.

[0042] Step 2: MoS 2 Preparation of reaction solution:

[0043] C 2 H 5 NS is a sulfur source, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is a molybdenum source, mixed at a molybdenum-sulfur molar ratio of 1:2, and then 150 ml of deionized water is added to form solution A; the vessel containing solution A is placed on a magnetic stirrer, the temperature is adjusted to 40 ° C and the speed is adjusted to 400 r / min, and heated and stirred for 50 min until the solution is clear and has no solid components, to obtain MoS 2 Reaction liquid.

[0044] Step 3: MoS 2 Preparation of interface layer:

[0045] The matrix (SiC fiber preform) in step 1 is completely immersed in the MoS 2 The reaction solution was immersed for 0.5 h to make the MoS 2 The reaction liquid is fully and evenly covered on the substrate; the soaked substrate is placed in a stainless steel reactor lined with polytetrafluoroethylene and reacted at 200°C for 24 hours; after the reaction is completed, the substrate is taken out after the temperature of the reactor drops to room temperature to obtain MoS 2 SiC fiber preform of the interface layer.

[0046] Step 4: Preparation of SiC substrate:

[0047] There will be MoS 2 The SiC fiber preform of the interface layer was placed in a chemical vapor deposition furnace with H 2 As carrier gas, CH 3SiCl 3 As the precursor, CO 2 As the reaction gas, the SiC substrate was prepared by chemical vapor infiltration; H 2 The flow rate is 800sccm, CO 2 The flow rate is 100 sccm;

[0048] The preparation process is as follows: the chemical vapor deposition furnace is heated from room temperature to 900°C at a heating rate of 5°C / min, the furnace pressure of the chemical vapor deposition furnace is kept within the range of 6kPa, and the deposition is performed for 30 hours. After the deposition is completed, the SiC fiber preform is taken out after the furnace temperature of the chemical vapor deposition furnace drops to room temperature. f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0049] After testing, the SiC prepared in this embodiment f / MoS 2 / SiC high temperature structural absorbing composite material, composed of 32wt% SiC fiber, 68wt% SiC matrix and 100nm thick MoS 2 Interface layer composition, MoS 2 The content of the interface layer is not included, and its bending strength is 210MPa, the real part of the complex dielectric constant is 20-25, and the imaginary part is 27-32.

[0050] Example 2

[0051] This embodiment provides a SiC f / MoS 2 / SiC high temperature structure absorbing composite material preparation method, the specific preparation process is as follows:

[0052] Step 1: Processing of SiC fiber preform:

[0053] The 2.5-dimensional SiC fiber braid is immersed in anhydrous ethanol and ultrasonically vibrated for 15 minutes. After the vibration, the SiC fiber braid is taken out, and the SiC fiber braid is placed in an oven at 100°C for 25 minutes and then taken out to obtain a SiC fiber preform after degumming treatment, which is used as a substrate for standby use. The SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fiber in the SiC fiber braid is 11 μm, the fiber bundle ratio is 1:1000, and the conductivity is 4S / m.

[0054] Step 2: MoS 2 Preparation of reaction solution:

[0055] C 2 H 5 NS is a sulfur source, (NH 4 )6 Mo 7 O 24 ·4H 2 O is a molybdenum source, and the molybdenum and sulfur are mixed in a molar ratio of 1:2, and then 120 ml of deionized water is added to form solution A; the vessel containing solution A is placed on a magnetic stirrer, the temperature is adjusted to 45 ° C and the speed is adjusted to 450r / min, and heated and stirred for 40 minutes until the solution is clear and has no solid components, and MoS 2 Reaction liquid.

[0056] Step 3: MoS 2 Preparation of interface layer:

[0057] The matrix (SiC fiber preform) in step 1 is completely immersed in the MoS 2 The MoS 2 The reaction liquid is fully and evenly covered on the substrate; the soaked substrate is placed in a stainless steel reactor lined with polytetrafluoroethylene and reacted at 220°C for 22 hours; after the reaction is completed, the substrate is taken out after the temperature of the reactor drops to room temperature to obtain MoS 2 SiC fiber preform of the interface layer.

[0058] Step 4: Preparation of SiC substrate:

[0059] There will be MoS 2 The SiC fiber preform of the interface layer was placed in a chemical vapor deposition furnace with H 2 As carrier gas, CH 3 SiCl 3 As the precursor, CO 2 As the reaction gas, the SiC substrate was prepared by chemical vapor infiltration; H 2 The flow rate is 850sccm, CO 2 The flow rate is 300 sccm;

[0060] The preparation process is as follows: the chemical vapor deposition furnace is heated from room temperature to 950°C at a heating rate of 6°C / min, the furnace pressure of the chemical vapor deposition furnace is maintained within the range of 6.5kPa, and the deposition is performed for 20 hours. After the deposition is completed, the SiC fiber preform is taken out after the furnace temperature of the chemical vapor deposition furnace drops to room temperature. f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0061] After testing, the SiC prepared in this embodiment f / MoS 2 / SiC high temperature structural absorbing composite material consists of 37wt% SiC fiber, 63wt% SiC matrix and 120nm thick MoS2 The interface layer is composed of MoS 2 The interface layer is not included in the content; its bending strength is 225MPa, the real part of the complex dielectric constant is 20-30, and the imaginary part is 30-37.

[0062] Example 3

[0063] This embodiment provides a SiC f / MoS 2 / SiC high temperature structure absorbing composite material preparation method, the specific preparation process is as follows:

[0064] Step 1: Processing of SiC fiber preform:

[0065] The SiC fiber braid is immersed in anhydrous ethanol and ultrasonically vibrated for 20 minutes. After the vibration, the SiC fiber braid is taken out, and the SiC fiber braid is placed in an oven at 100°C for 20 minutes to obtain a SiC fiber preform after degumming treatment, which is used as a substrate for standby use. The SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fiber in the SiC fiber braid is 12 μm, the fiber bundle ratio is 1:1000, and the conductivity is 5 S / m.

[0066] Step 2: MoS 2 Preparation of reaction solution:

[0067] C 2 H 5 NS is a sulfur source, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is a molybdenum source, and the molybdenum and sulfur are mixed in a molar ratio of 1:2, and then 250 ml of deionized water is added to form a solution A; the vessel containing the formed solution A is placed on a magnetic stirrer, the temperature is adjusted to 50 ° C and the speed is adjusted to 550 r / min, and heated and stirred for 40 minutes until the solution is clear and has no solid components, and MoS 2 Reaction liquid.

[0068] Step 3: MoS 2 Preparation of interface layer:

[0069] The matrix (SiC fiber preform) in step 1 is completely immersed in the MoS 2 The reaction solution was immersed for 1 h to make the MoS 2 The reaction liquid is fully and evenly covered on the substrate; the soaked substrate is placed in a stainless steel reactor lined with polytetrafluoroethylene and reacted at 250°C for 20 hours; after the reaction is completed, the substrate is taken out after the temperature of the reactor drops to room temperature to obtain MoS2 SiC fiber preform of the interface layer.

[0070] Step 4: Preparation of SiC substrate:

[0071] There will be MoS 2 The SiC fiber preform of the interface layer was placed in a chemical vapor deposition furnace with H 2 As carrier gas, CH 3 SiCl 3 As the precursor, CO 2 As the reaction gas, the SiC substrate was prepared by chemical vapor infiltration; H 2 The flow rate is 900sccm, CO 2 The flow rate is 400 sccm;

[0072] The preparation process is as follows: the chemical vapor deposition furnace is heated from room temperature to 1000°C at a heating rate of 8°C / min, the furnace pressure of the chemical vapor deposition furnace is kept within the range of 7kPa, and the deposition is performed for 17 hours. After the deposition is completed, the SiC fiber preform is taken out after the furnace temperature of the chemical vapor deposition furnace drops to room temperature. f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0073] After testing, the SiC prepared in this embodiment f / MoS 2 / SiC high temperature structural absorbing composite material, composed of 40wt% SiC fiber, 60wt% SiC matrix and 130nm thick MoS 2 The interface layer is composed of MoS 2 The interface layer is not included in the content, and its bending strength is 220MPa, the real part of the complex dielectric constant is 24-39, and the imaginary part of the complex dielectric constant is 40-80.

[0074] Example 4

[0075] This embodiment provides a SiC f / MoS 2 / SiC high temperature structure absorbing composite material preparation method, the specific preparation process is as follows:

[0076] Step 1: Processing of SiC fiber preform:

[0077] The SiC fiber braid is immersed in anhydrous ethanol and ultrasonically vibrated for 30 minutes. After the vibration, the SiC fiber braid is taken out, and the SiC fiber braid is placed in an oven at 120°C for 15 minutes and then taken out to obtain a SiC fiber preform after degumming treatment, which is used as a substrate for standby use. The SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fiber in the SiC fiber braid is 12 μm, the fiber bundle ratio is 1:1000, and the conductivity is 6 S / m.

[0078] Step 2: MoS 2 Preparation of reaction solution:

[0079] C 2 H 5 NS is a sulfur source, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is a molybdenum source, and the molybdenum and sulfur are mixed in a molar ratio of 1:2, and then 150 ml of deionized water is added to prepare a solution; the vessel containing the solution is placed on a magnetic stirrer, the temperature is adjusted to 50 ° C and the speed is adjusted to 600 r / min, and heated and stirred for 30 minutes until the solution is clear and has no solid components, to obtain MoS 2 Reaction liquid.

[0080] Step 3: MoS 2 Preparation of interface layer:

[0081] The matrix (SiC fiber preform) in step 1 is completely immersed in the MoS 2 The reaction solution was immersed for 1 h to make the MoS 2 The reaction liquid is fully and evenly covered on the substrate; the soaked substrate is placed in a stainless steel reactor lined with polytetrafluoroethylene and reacted at 250°C for 20 hours; after the reaction is completed, the substrate is taken out after the temperature of the reactor drops to room temperature to obtain MoS 2 SiC fiber preform of the interface layer.

[0082] Step 4: Preparation of SiC substrate:

[0083] There will be MoS 2 The SiC fiber preform of the interface layer was placed in a chemical vapor deposition furnace with H 2 As carrier gas, CH 3 SiCl 3 As the precursor, CO 2 As the reaction gas, the SiC substrate was prepared by chemical vapor infiltration; H 2 The flow rate is 820sccm, CO 2 The flow rate is 600 sccm;

[0084] The preparation process is as follows: the chemical vapor deposition furnace is heated from room temperature to 1100°C at a heating rate of 10°C / min, the furnace pressure of the chemical vapor deposition furnace is kept within the range of 8kPa, and the deposition is performed for 15 hours. After the deposition is completed, the SiC fiber preform is taken out after the furnace temperature of the chemical vapor deposition furnace drops to room temperature. f / MoS 2 Preparation of / SiC high temperature structural microwave absorbing composite materials.

[0085] After testing, the SiC prepared in this embodiment f / MoS 2 / SiC high temperature structural absorbing composite material, composed of 50wt% SiC fiber, 50wt% SiC matrix and 150nm thick MoS 2 The interface layer is composed of MoS 2 The interface layer is not included in the content, and its bending strength is 250MPa, the real part of the complex dielectric constant is 30-35, and the imaginary part of the complex dielectric constant is 48-60.

[0086] In summary, the SiC prepared by the present invention f / MoS 2 / SiC high temperature structural absorbing composite material has a bending strength of 210-250MPa, a real part of a complex dielectric constant of 20-39, and an imaginary part of a complex dielectric constant of 27-80. It not only meets the required electrical properties but also has good absorbing properties.

[0087] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0088] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A SiC f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: First, the treated SiC fiber preform is completely immersed in the MoS2 reaction liquid, and after soaking for a specified time, the MoS2 reaction liquid is evenly covered on the SiC fiber preform; then, the immersed SiC fiber preform is placed in a reaction container for reaction to obtain a SiC fiber preform with a MoS2 interface layer; finally, the SiC fiber preform with the MoS2 interface layer is subjected to a gas phase reaction by chemical vapor infiltration to prepare a SiC matrix, thereby completing the SiC f Preparation of / MoS2 / SiC high temperature structural microwave absorbing composite materials.

2. SiC according to claim 1 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The specific steps include: Step 1, treatment of the SiC fiber preform: after ultrasonic cleaning the SiC fiber preform with anhydrous ethanol, the preform is placed in an oven for drying to obtain the treated SiC fiber preform; Step 2, preparation of MoS2 reaction solution: mixing a sulfur source and a molybdenum source at a molar ratio of molybdenum to sulfur of 1:2, adding deionized water, heating and stirring until the mixture is uniform to obtain a MoS2 reaction solution; Step 3: Preparation of MoS2 interface layer: Completely immerse the treated SiC fiber preform in the MoS2 reaction solution, and after soaking for a specified time, allow the MoS2 reaction solution to fully cover the SiC fiber preform; place the soaked SiC fiber preform in a reaction container, and react at a temperature of 200 to 250° C. for 20 to 24 hours. After the reaction is completed, take out the SiC fiber preform with the MoS2 interface layer after the temperature of the reactor drops to room temperature; Step 4: Preparation of SiC matrix: Place the SiC fiber preform with MoS2 interface layer into a chemical vapor deposition furnace for gas phase reaction to prepare SiC matrix, thereby completing SiC f Preparation of / MoS2 / SiC high temperature structural microwave absorbing composite materials.

3. SiC according to claim 2 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The step 1 is specifically as follows: Step 1.1, immersing the SiC fiber preform in anhydrous ethanol, and ultrasonically vibrating for 10 to 30 minutes, and taking out the SiC fiber preform after the vibration ends; Step 1.2, placing the SiC fiber preform in an oven at 80-120° C. for 15-30 minutes and then taking it out to obtain a SiC fiber preform after debonding.

4. SiC according to claim 2 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The step 2 is specifically as follows: Step 2.1, using C2H5NS as sulfur source, (NH4)6Mo7O 24 4H2O is used as the molybdenum source, mixed with molybdenum and sulfur in a molar ratio of 1:2, and 120-250 ml of deionized water is added to form solution A; Step 2.2, place the vessel containing the solution A on a magnetic stirrer, adjust the temperature to 40-50°C and the rotation speed to 400-600 r / min, and heat and stir for 30-50 min to obtain a MoS2 reaction solution.

5. SiC according to claim 2 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The specified time in step 3 is 0.5 to 1 h.

6. SiC according to claim 2 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The gas phase reaction in step 4 is specifically as follows: The chemical vapor deposition furnace is heated from room temperature to 900-1100° C. at a heating rate of 5-10° C. / min, the furnace pressure of the chemical vapor deposition furnace is maintained in the range of 6-8 kPa, and the SiC substrate is prepared by deposition for 15-30 hours; After the deposition is completed, the SiC f / MoS2 / SiC high temperature structural microwave absorbing composite material.

7. SiC according to claim 6 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: In step 4, the gas phase reaction uses H2 as carrier gas and the H2 flow rate is 800-900 sccm; uses CH3SiCl3 as precursor, uses CO2 as reaction gas and the CO2 flow rate is 100-600 sccm.

8. SiC according to claim 1 f A method for preparing a / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The SiC fiber preform is a 2.5-dimensional SiC fiber braid, and the diameter of the SiC fibers in the SiC fiber braid is 10-12 μm, the fiber bundle ratio is 1:1000, and the electrical conductivity is 3-6 S / m.

9. A SiC f / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The high-temperature structural absorbing composite material is prepared by the preparation method described in any one of claims 1 to 8, comprising: 32 to 50 wt% SiC fiber, 50 to 68 wt% SiC matrix and a MoS2 interface layer located therebetween.

10. The SiC according to claim 9 f / MoS2 / SiC high temperature structural wave absorbing composite material, characterized in that: The thickness of the MoS2 interface layer is 100-150 nm.

Images