Flexible heat-insulating silicon-based material for rockets and method for preparing same

Abstract

The application relates to a flexible heat-insulating silicon-based material for rockets, which comprises, in sequence: a silicone rubber layer, wherein hollow glass microspheres are dispersed; and a composite fabric layer, wherein the composite fabric layer comprises quartz fabric and porcelainized silicone rubber coated on the surface of the quartz fabric, and the porcelainized silicone rubber is internally dispersed with hollow microspheres. The flexible heat-insulating silicon-based material for rockets and the preparation method thereof are provided, the silicone rubber layer and the composite fabric layer are combined together, the hollow glass microspheres are dispersed in the silicone rubber layer, the silicone rubber layer can resist heat flushing, the composite fabric layer has the performances of low density and high heat insulation, and can be deformed at high temperature, so as to adapt to the volume expansion of the rocket engine shell. Therefore, the flexible heat-insulating silicon-based material for rockets provided by the application has the performances of high-temperature resistance, low density, heat insulation and high-temperature flexibility.

Description

Technical Field

[0001] This application relates to the aerospace field, and in particular to thermal insulation materials for rockets. Background Technology

[0002] Some rocket engine casings are rotating components and high-temperature, high-pressure structures. During operation, the external casing is subjected to prolonged exposure to high-temperature airflow reaching 1400°C to 1500°C. The outer thermal protection layer must maintain good dimensional retention under this prolonged exposure, with a recoil of no more than 2mm. Simultaneously, this thermal protection also needs to possess low density and good thermal insulation to ensure that the temperature of the inner carbon fiber structure layer does not exceed 200°C under external high-temperature conditions. Furthermore, rocket engines generate high internal pressure during operation, causing the engine casing to expand due to this pressure. Therefore, the outer thermal protection layer must withstand external high temperatures while maintaining a certain degree of flexibility to adapt to the dimensional changes caused by the expansion of the engine casing, preventing fracture due to expansion stress and maintaining structural integrity. However, currently known thermal protection materials struggle to simultaneously possess multiple properties such as high-temperature resistance, low density, thermal insulation, and flexibility under high temperatures. Summary of the Invention

[0003] This application provides a flexible thermal insulation silicon-based material for rockets and its preparation method, in order to solve the technical problem that thermal protection materials are difficult to possess multiple properties such as high temperature resistance, low density, thermal insulation and flexibility at high temperatures at the same time.

[0004] In a first aspect, embodiments of this application provide a flexible thermal insulation silicon-based material for rockets, comprising sequentially stacked layers:

[0005] A silicone rubber layer, wherein hollow glass microspheres are dispersed inside the silicone rubber layer;

[0006] A composite fabric layer comprising a quartz fabric and a ceramicized silicone rubber coating the surface of the quartz fabric, wherein hollow microspheres are dispersed within the ceramicized silicone rubber.

[0007] In some embodiments of this application, the mass ratio of the hollow microspheres to the ceramicized silicone rubber is 10-40:103-115; and / or,

[0008] In the silicone rubber layer, the mass ratio of hollow glass microspheres to silicone rubber is 20-80:100; and / or,

[0009] The quartz fabric has a fiber volume content of 25-35%.

[0010] Secondly, embodiments of this application provide a method for preparing a flexible thermal insulation silicon-based material for rockets, used to prepare the flexible thermal insulation silicon-based material for rockets described in any embodiment of the first aspect. The method for preparing the flexible thermal insulation silicon-based material for rockets includes the following steps:

[0011] The ceramicizable powder, hollow microspheres, and organosilicon resin are mixed to obtain the first mixture.

[0012] A quartz fabric is provided, and the quartz fabric is impregnated with the first mixture to obtain a prepreg;

[0013] Provides a silicone rubber layer with hollow glass microspheres dispersed inside;

[0014] The silicone rubber layer is stacked with the prepreg to obtain a flexible thermal insulation silicone-based material precursor.

[0015] The flexible thermal insulation silicon-based material precursor is heated to a predetermined temperature under external pressure to obtain the flexible thermal insulation silicon-based material.

[0016] In some embodiments of this application, the mixing of ceramic-forming powder, hollow microspheres, and organosilicon resin is wherein the mass ratio of the ceramic-forming powder, the hollow microspheres, and the organosilicon resin is 3-15:10-40:100; and / or,

[0017] In the silicone rubber layer, the mass ratio of hollow glass microspheres to silicone rubber is 20-80:100.

[0018] In some embodiments of this application, the fiber volume content of the quartz fabric is 25-35%.

[0019] In some embodiments of this application, the predetermined temperature is 150-180°C.

[0020] In some embodiments of this application, providing a silicone rubber layer with hollow glass microspheres dispersed inside includes the following steps:

[0021] Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture;

[0022] The silicone rubber layer is prepared using the second mixture.

[0023] In some embodiments of this application, the preparation of the silicone rubber layer using the second mixture includes the following steps:

[0024] The second mixture is added to the mold and leveled to form a thin liquid layer.

[0025] The liquid thin layer is vulcanized to obtain a silicone rubber sheet;

[0026] Several silicone rubber sheets are stacked and bonded together with an adhesive to form the silicone rubber layer.

[0027] In some embodiments of this application, the thickness of the silicone rubber sheet is 3-5 mm, and the thickness of the silicone rubber layer is 5-20 mm.

[0028] In some embodiments of this application, the adhesive is at least one of GD414 or GP-02A(B).

[0029] The technical solutions provided in this application have the following advantages compared with the prior art:

[0030] This application provides a flexible thermal insulation silicon-based material for rockets and its preparation method. By combining a silicone rubber layer and a composite fabric layer, hollow glass microspheres are dispersed inside the silicone rubber layer, enabling the silicone rubber layer to withstand heat erosion. The composite fabric layer has low density, high thermal insulation performance, and can deform at high temperatures to adapt to the volume expansion of the rocket engine shell. Therefore, the flexible thermal insulation silicon-based material for rockets provided by this application simultaneously possesses the properties of high temperature resistance, low density, thermal insulation, and flexibility at high temperatures. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart illustrating a method for preparing a flexible thermal insulation silicon-based material for rockets, as provided in an embodiment of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Unless otherwise specified, the terminology used herein should be understood as having the meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any conflict, this specification shall prevail.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Currently, there are technical challenges in using thermal protection materials for rocket engine casings to simultaneously possess multiple properties such as high temperature resistance, low density, heat insulation, and flexibility at high temperatures.

[0038] The technical solution provided in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0039] In a first aspect, embodiments of this application provide a flexible thermal insulation silicon-based material for rockets, comprising sequentially stacked layers:

[0040] A silicone rubber layer, wherein hollow glass microspheres are dispersed inside the silicone rubber layer;

[0041] A composite fabric layer comprising a quartz fabric and a ceramicized silicone rubber coating the surface of the quartz fabric, wherein hollow microspheres are dispersed within the ceramicized silicone rubber.

[0042] The flexible thermal insulation silicon-based material for rockets provided in this application is used as a thermal protection layer for the outer shell of a rocket engine. The engine shell of this type of rocket is a rotating component and a high-temperature, internally pressurized structural component. This requires the thermal protection layer to not only resist high-temperature erosion but also withstand the pressure from the expansion of the rocket shell. At the same time, it must also meet the general thermal protection requirements of a rocket engine outer shell, such as thermal insulation and low density.

[0043] The hollow glass microspheres described in this application refer to hollow spheres with a particle size in the micrometer range and made of glass.

[0044] The hollow microspheres described in this application refer to hollow spheres with a particle size in the micrometer range. The material can be any conventional material in the field, such as SiO2 hollow microspheres or phenolic hollow microspheres.

[0045] This application uses a silicone rubber layer as the outer layer, with hollow glass microspheres dispersed inside. The ceramicized silicone rubber itself has high thermal stability and resistance to heat erosion. The inner layer is a composite fabric layer with a quartz fabric skeleton. Quartz fabric itself has high thermal stability and will not change under high temperature conditions. The structure of quartz fabric contains a large number of pores, which helps to reduce the density of the material, improve the thermal insulation capacity of the material, and still has a certain deformation capacity at high temperatures, which can adapt to most of the expansion deformation of the rocket shell without affecting the outer silicone rubber layer. The ceramicized silicone rubber covering the surface of the quartz fabric further enhances the heat resistance of the composite fabric layer, and can also improve the strength of the composite fabric layer to a certain extent. It also increases the material compatibility between the composite fabric layer and the silicone rubber layer, so that the composite fabric layer and the silicone rubber layer can be more tightly bonded.

[0046] This application combines a silicone rubber layer and a composite fabric layer, dispersing hollow glass microspheres inside the silicone rubber layer to enable the silicone rubber layer to withstand heat erosion; the composite fabric layer has low density, high thermal insulation properties, and can deform at high temperatures to adapt to the volume expansion of the rocket engine shell; therefore, the flexible thermal insulation silicone-based material for rockets provided by this application has the properties of high temperature resistance, low density, thermal insulation, and flexibility at high temperatures.

[0047] In some embodiments of this application, the mass ratio of the hollow microspheres to the ceramicized silicone rubber is 10-40:103-115; and / or,

[0048] In the silicone rubber layer, the mass ratio of hollow glass microspheres to silicone rubber is 20-80:100; and / or,

[0049] The quartz fabric has a fiber volume content of 25-35%.

[0050] Hollow microspheres can increase the thermal insulation capacity of ceramicized silicone rubber, but too many hollow microspheres will affect the material strength of ceramicized silicone rubber. Setting the mass ratio of hollow microspheres to ceramicized silicone rubber to 10-40:103-115 can increase the thermal insulation capacity of ceramicized silicone rubber without affecting its material strength.

[0051] The primary function of the silicone rubber layer is to resist heat erosion. A higher mass ratio of hollow glass microspheres results in stronger heat erosion resistance. However, an excessively high mass ratio of hollow glass microspheres can also negatively impact the material strength of the silicone rubber. Setting the mass ratio of hollow glass microspheres to silicone rubber to 20-80:100 can simultaneously ensure both the heat erosion resistance and material strength of the silicone rubber layer.

[0052] The lower the fiber volume content of quartz fabric, the better the density, thermal insulation performance, and high-temperature deformation capacity of the composite fabric layer; however, too low a fiber volume content of quartz fabric will affect the material strength of the composite fabric layer. Setting the fiber volume content of quartz fabric to 25-35% can reduce the density of the composite fabric layer as much as possible, increase its thermal insulation capacity and high-temperature deformation capacity, and ensure that it has appropriate material strength.

[0053] Secondly, embodiments of this application provide a method for preparing a flexible thermal insulation silicon-based material for rockets, used to prepare the flexible thermal insulation silicon-based material for rockets described in any embodiment of the first aspect. Please refer to... Figure 1 The preparation method of the flexible thermal insulation silicon-based material for rockets includes the following steps:

[0054] S1: Mix ceramic powder, hollow microspheres and organosilicon resin to obtain the first mixture;

[0055] S2: Provide a quartz fabric, and impregnate the quartz fabric with the first mixture to obtain a prepreg;

[0056] S3: Provides a silicone rubber layer with hollow glass microspheres dispersed inside;

[0057] S4: Stack the silicone rubber layer with the prepreg to obtain a flexible thermal insulation silicone-based material precursor;

[0058] S5: The flexible heat-insulating silicon-based material precursor is heated at a predetermined temperature under external pressure to obtain the flexible heat-insulating silicon-based material.

[0059] In step S5, the flexible thermal insulation silicone-based material precursor is heated to a predetermined temperature under external pressure, causing the first mixture on the surface of the prepreg to vulcanize and vitrify, forming the composite fabric layer. Furthermore, at the contact points between the composite fabric layer and the silicone rubber layer, the vitrified silicone rubber mixes with the silicone rubber during the vulcanization and vitrification process to form a continuous phase, resulting in a tight bond between the composite fabric layer and the silicone rubber layer to form the flexible thermal insulation silicone-based material.

[0060] The primary function of external pressure is to bond the prepreg and silicone rubber layer together. External pressure can be provided using conventional equipment, such as a hot press. This application also provides a preferred method for providing external pressure and a predetermined temperature: first, a flexible insulating silicone-based material precursor is placed in a sealed bag and a vacuum is applied; at this point, the external pressure is atmospheric pressure, which tightly bonds the prepreg and silicone rubber layer together. Subsequently, the sealed bag is placed in a heating appliance, such as an oven, and the temperature is raised to the predetermined temperature for heating.

[0061] In some embodiments of this application, the mixing of ceramic-forming powder, hollow microspheres, and organosilicon resin is wherein the mass ratio of the ceramic-forming powder, the hollow microspheres, and the organosilicon resin is 3-15:10-40:100; and / or,

[0062] In the silicone rubber layer, the mass ratio of hollow glass microspheres to silicone rubber is 20-80:100.

[0063] The ceramicizable powder and the organosilicon resin are used together at high temperature to form ceramicized silicone rubber. The mass ratio of the ceramicizable powder, the hollow microspheres and the organosilicon resin is 3-15:10-40:100, which can obtain a material with a mass ratio of hollow microspheres to ceramicized silicone rubber of 10-40:103-115.

[0064] In some embodiments of this application, the fiber volume content of the quartz fabric is 25-35%.

[0065] In some embodiments of this application, the predetermined temperature is 150-180°C.

[0066] In some embodiments of this application, providing a silicone rubber layer with hollow glass microspheres dispersed inside includes the following steps:

[0067] S31: Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture;

[0068] S32: Prepare the silicone rubber layer using the second mixture.

[0069] The method for preparing the silicone rubber layer in step S32 using the second mixture can be a conventional method in the art, such as heating or vulcanizing it at room temperature.

[0070] In some embodiments of this application, the preparation of the silicone rubber layer using the second mixture includes the following steps:

[0071] S321: Add the second mixture to the mold and level it to form a thin liquid layer;

[0072] S322: Vulcanize the liquid thin layer to obtain a silicone rubber sheet;

[0073] S323: Several silicone rubber sheets are stacked and bonded together with an adhesive to form the silicone rubber layer.

[0074] The reason for preparing thinner silicone rubber sheets first and then bonding them together to form a silicone rubber layer is that the second mixture undergoes volume changes during vulcanization. If the mixture is too thick, it can easily lead to uneven thickness of the resulting silicone rubber layer. Therefore, preparing silicone rubber sheets of uniform thickness first and then bonding them together makes it easier to form a silicone rubber layer of uniform thickness.

[0075] In some embodiments of this application, the thickness of the silicone rubber sheet is 3-5 mm, and the thickness of the silicone rubber layer is 9-11 mm.

[0076] In some embodiments of this application, the adhesive is at least one of GD414 or GP-02A(B).

[0077] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0078] Example 1

[0079] This embodiment provides a method for preparing a flexible thermal insulation silicon-based material for rockets, including the following steps:

[0080] Sa: The ceramicizable powder, hollow microspheres and organosilicon resin are mixed in a mass ratio of 3:10:100 to obtain the first mixture;

[0081] Sb: A quartz fabric with a fiber volume content of 25% is provided, and the quartz fabric is impregnated with the first mixture to obtain a prepreg;

[0082] Sc: Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture, wherein the mass ratio of hollow glass microspheres to silicone resin is 20:100;

[0083] Sd: The second mixture is added to the mold and leveled to form a thin liquid layer;

[0084] Se: The liquid thin layer is vulcanized at room temperature to obtain a silicone rubber sheet with a thickness of 3 mm;

[0085] Sf: Several silicone rubber sheets are stacked and bonded together with adhesive to form a silicone rubber layer with a thickness of 9mm;

[0086] Sg: The silicone rubber layer is stacked with the prepreg to obtain a flexible thermal insulation silicone-based material precursor;

[0087] Sh: The flexible thermal insulation silicon-based material precursor is added to a sealed bag and vacuumed. The sealed bag is then placed in an oven and heated at 150°C for 2 hours. The obtained flexible thermal insulation silicon-based material is then removed from the sealed bag.

[0088] Example 2

[0089] This embodiment provides a method for preparing a flexible thermal insulation silicon-based material for rockets, including the following steps:

[0090] Sa: The ceramicizable powder, hollow microspheres, and organosilicon resin are mixed in a mass ratio of 15:40:100 to obtain the first mixture;

[0091] Sb: A quartz fabric with a fiber volume content of 35% is provided, and the quartz fabric is impregnated with the first mixture to obtain a prepreg;

[0092] Sc: Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture, wherein the mass ratio of hollow glass microspheres to silicone resin is 80:100;

[0093] Sd: The second mixture is added to the mold and leveled to form a thin liquid layer;

[0094] Se: The liquid thin layer is vulcanized at room temperature to obtain a silicone rubber sheet with a thickness of 5 mm;

[0095] Sf: Several silicone rubber sheets are stacked and bonded together with adhesive to form a silicone rubber layer with a thickness of 10mm;

[0096] Sg: The silicone rubber layer is stacked with the prepreg to obtain a flexible thermal insulation silicone-based material precursor;

[0097] Sh: The flexible thermal insulation silicon-based material precursor is added to a sealed bag and vacuumed. The sealed bag is then placed in an oven and heated at 180°C for 2 hours. The obtained flexible thermal insulation silicon-based material is then removed from the sealed bag.

[0098] Example 3

[0099] This embodiment provides a method for preparing a flexible thermal insulation silicon-based material for rockets, including the following steps:

[0100] Sa: The ceramicizable powder, hollow microspheres and organosilicon resin are mixed in a mass ratio of 7:19:100 to obtain the first mixture;

[0101] Sb: A quartz fabric with a fiber volume content of 28% is provided, and the quartz fabric is impregnated with the first mixture to obtain a prepreg;

[0102] Sc: Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture, wherein the mass ratio of hollow glass microspheres to silicone resin is 60:100;

[0103] Sd: The second mixture is added to the mold and leveled to form a thin liquid layer;

[0104] Se: The liquid thin layer is vulcanized at room temperature to obtain a silicone rubber sheet with a thickness of 3 mm;

[0105] Sf: Several silicone rubber sheets are stacked and bonded together with adhesive to form a silicone rubber layer with a thickness of 9mm;

[0106] Sg: The silicone rubber layer is stacked with the prepreg to obtain a flexible thermal insulation silicone-based material precursor;

[0107] Sh: The flexible thermal insulation silicon-based material precursor is added to a sealed bag and vacuumed. The sealed bag is then placed in an oven and heated at 160°C for 2 hours. The obtained flexible thermal insulation silicon-based material is then removed from the sealed bag.

[0108] Relevant experimental and effect data:

[0109] The flexible thermal insulation silicon-based materials obtained in Examples 1-3 were subjected to density measurement, thermal insulation performance testing, high-temperature erosion testing, and material tensile strength testing. Specifically,

[0110] The method for density measurement is as follows: GB / T533-2008 "Determination of density of vulcanized rubber or thermoplastic rubber"

[0111] The method for testing thermal insulation performance is: GB / T10295-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Heat Flow Meter Method"

[0112] The method for high-temperature erosion testing is as follows: typical thermal environment electric arc wind tunnel test or GJB323A-96 "Test Methods for Ablation of Ablation Materials".

[0113] The method for testing the tensile strength of materials is: GB / T528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber"

[0114] The obtained data is shown in the table below:

[0115]

[0116]

[0117] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0118] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. For associations involving three or more related objects described using "and / or", it indicates that any one of the three related objects can exist alone, or at least two of them can exist simultaneously. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0119] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A flexible thermal insulation silicon-based material suitable for the volume expansion of rocket engine casings, characterized in that, The flexible thermal insulation silicon-based material for the rocket engine casing comprises sequentially stacked layers: A silicone rubber layer, wherein hollow glass microspheres are dispersed inside the silicone rubber layer, and the mass ratio of hollow glass microspheres to silicone rubber is 20-80:100; A composite fabric layer comprising a quartz fabric and a ceramicized silicone rubber coating the surface of the quartz fabric, wherein hollow microspheres are dispersed inside the ceramicized silicone rubber. In the vitrified silicone rubber, the mass ratio of the hollow microspheres to the vitrified silicone rubber is 10-40:103-115; the fiber volume content of the quartz fabric is 25-35%. The outer layer of the flexible heat-insulating silicon-based material is a silicone rubber layer, and the inner layer is a composite fabric layer.

2. A method for preparing a flexible thermal insulation silicon-based material suitable for the volume expansion of a rocket engine casing as described in claim 1, characterized in that, The method for preparing the flexible heat-insulating silicon-based material for the rocket engine casing includes the following steps: The ceramicizable powder, hollow microspheres, and organosilicon resin are mixed to obtain the first mixture. A quartz fabric is provided, and the quartz fabric is impregnated with the first mixture to obtain a prepreg; Provides a silicone rubber layer with hollow glass microspheres dispersed inside; The silicone rubber layer is stacked with the prepreg to obtain a flexible thermal insulation silicone-based material precursor. The flexible thermal insulation silicon-based material precursor is heated to a predetermined temperature under external pressure to obtain the flexible thermal insulation silicon-based material.

3. The method for preparing the flexible thermal insulation silicon-based material according to claim 2, characterized in that, The process involves mixing ceramic powder, hollow microspheres, and organosilicon resin, wherein the mass ratio of the ceramic powder, the hollow microspheres, and the organosilicon resin is 3-15:10-40:

100.

4. The method for preparing the flexible thermal insulation silicon-based material according to claim 2, characterized in that, The predetermined temperature is 150-180℃.

5. The method for preparing the flexible thermal insulation silicon-based material according to claim 2, characterized in that, The process of providing the silicone rubber layer with hollow glass microspheres dispersed inside includes the following steps: Hollow glass microspheres, silicone resin, and curing agent are mixed to obtain a second mixture; The silicone rubber layer is prepared using the second mixture.

6. The method for preparing the flexible thermal insulation silicon-based material according to claim 5, characterized in that, The preparation of the silicone rubber layer using the second mixture includes the following steps: The second mixture is added to the mold and leveled to form a thin liquid layer; The liquid thin layer is vulcanized to obtain a silicone rubber sheet; Several silicone rubber sheets are stacked and bonded together with an adhesive to form the silicone rubber layer.

7. The method for preparing the flexible thermal insulation silicon-based material according to claim 6, characterized in that, The thickness of the silicone rubber sheet is 3-5 mm, and the thickness of the silicone rubber layer is 5-20 mm.

8. The method for preparing the flexible thermal insulation silicon-based material according to claim 6, characterized in that, The adhesive is GD414.

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