Three-dimensional orthogonal woven ablation-resistant thermal-insulation composite material and preparation method thereof

Abstract

The application discloses a three-dimensional orthogonal woven ablation-resistant and heat-insulating composite material and a preparation method thereof, and belongs to the field of functional composite materials. The three-dimensional orthogonal woven hybrid preform is prepared by adopting carbon fibers and alumina fibers as raw materials, a three-layer structure of carbon fibers-alumina fibers-carbon fibers, and alternately binding the three-layer structure by using normal yarns through a three-dimensional weaving process; then, a boron-modified phenolic resin matrix is used to realize the preparation of the three-dimensional orthogonal woven ablation-resistant and heat-insulating composite material through a resin transfer molding technology. The three-dimensional orthogonal woven ablation-resistant and heat-insulating composite material prepared by the application is ablation-resistant, heat-insulating, high in bearing capacity and low in density, and meets the requirements of structural lightweight, ablation resistance and heat-insulating performance of a super-speed aircraft.

Description

Technical Field

[0001] This invention relates to a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material and its preparation method, belonging to the field of functional composite materials. Background Technology

[0002] Aerospace equipment components are often in extreme thermo-mechanical coupling environments during service. For example, when a hypersonic vehicle flies at high Mach numbers, the temperature generated by aerodynamic heating can reach 1800°C. When a rocket engine is working, the high-speed hot flow generated in the combustion chamber washes over the nozzle, and the temperature of the most demanding throat liner can exceed 2000°C. This places extremely stringent requirements on the high temperature resistance and load-bearing capacity of materials.

[0003] Traditional high-temperature components at the hot end of aerospace are mostly made of metal alloys or laminated composite materials, with a coating applied to the surface to achieve heat protection. However, this structure has disadvantages such as large mass, poor heat insulation, and difficulty in ensuring durability.

[0004] Currently, carbon / phenolic resin (C / Ph) is a typical carbon fiber reinforced composite material. It has low density, low composition, and short preparation cycle, and is widely used in the ablation-resistant layer of nozzles. However, the ablation performance of traditional C / Ph composite materials under ultra-high temperature, high pressure, and long-term operating conditions is increasingly unable to meet the thermal protection requirements of new high-performance aircraft. Therefore, how to improve the ablation performance and thermal insulation performance of C / Ph composite materials has become a hot topic in the research of advanced thermal protection materials.

[0005] Some researchers have used three-dimensional woven carbon fiber preforms as reinforcement, injected phenolic resin using the RTM process, introduced PBSZ through low-temperature carbonization and liquid-phase impregnation, and finally cured to obtain C / Ph-PBSZ composite materials; however, this process is complex. Other researchers have prepared high-temperature insulation materials by first impregnating carbon fibers with a slurry, then winding, curing, and high-temperature carbonizing; however, the slurry is prone to detachment, affecting service life. Still others have prepared carbon-carbon composite materials using carbon fiber preforms as a skeleton through chemical vapor deposition densification and purification processes. While these materials have long lifespans and are erosion-resistant, their high thermal conductivity results in poor insulation, long production cycles, and high costs. Still others have used carbon fiber soft felt as the main body, winding it around a carbon-carbon composite inner cylinder for support, and fixing the outermost layer of the soft felt with a rigid outer cylinder, using adhesives and colloids for fixation; however, this composite process is very difficult, the overall quality is poor, and the improvement in insulation is not significant. In addition to improving the structure of carbon fibers and preforms, some researchers have also modified composite resins or added some reinforcing agents to improve performance. Although these methods improve the performance of the final composite material, it is difficult to meet the requirements of high-temperature components for aerospace hot ends.

[0006] Therefore, how to improve the ablation performance, thermal insulation performance, load-bearing performance, and reduce the density of carbon / resin composite materials so that they can be used in the field of high-temperature components at the hot end of aerospace is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] [Technical Issues]

[0008] C / Ph composite materials cannot simultaneously satisfy both high ablation performance and high thermal insulation performance;

[0009] The preparation of C / Ph composite materials is complex;

[0010] Carbon-carbon composite materials have too high thermal conductivity, resulting in poor insulation performance, long production cycles, and high costs.

[0011] [Technical Solution]

[0012] To address the aforementioned issues, this invention utilizes carbon fiber and alumina fiber as raw materials, employing a three-layer structure of carbon fiber-alumina fiber-carbon fiber. The three layers are alternately bound using normal yarns, and a three-dimensional orthogonal woven hybrid preform is prepared through a three-dimensional weaving process. Subsequently, a boron-modified phenolic resin matrix is ​​used, and resin transfer molding technology is employed to prepare the three-dimensional orthogonal woven ablation-resistant thermal insulation composite material. The three-dimensional orthogonal woven ablation-resistant thermal insulation composite material prepared by this invention exhibits high ablation resistance, thermal insulation, load-bearing capacity, and low density, meeting the requirements for lightweight structure, ablation resistance, and thermal insulation performance of hypersonic aircraft.

[0013] The first objective of this invention is to provide a method for preparing a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material, comprising the following steps:

[0014] (1) Weaving three-dimensional orthogonal hybrid prefabricated structures:

[0015] The orthogonally placed warp yarns have a three-layer structure from top to bottom: an upper carbon fiber layer, an alumina fiber layer, and a lower carbon fiber layer. The thickness ratio of the upper carbon fiber layer, the alumina fiber layer, and the lower carbon fiber layer is 1:2-3:1.

[0016] The weft yarns and warp yarns are laid out in a completely consistent and corresponding manner;

[0017] Carbon fiber is used as the normal yarn;

[0018] Perform three-dimensional orthogonal weaving to form a weaving unit; then continue to repeat until the desired size is achieved, resulting in a three-dimensional orthogonal hybrid preform.

[0019] (2) Composite:

[0020] A three-dimensional orthogonal hybrid preform was cured using resin transfer molding technology to obtain a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material.

[0021] In one embodiment of the present invention, the carbon fiber in step (1) is T700 or T800 with a fineness of 600-800 tex; the alumina fiber is one or more of Nextel 610, Nextel 720, and ALF-FB3 with a fineness of 600-800 tex.

[0022] In one embodiment of the present invention, the warp density of the three-dimensional orthogonal weaving in step (1) is 20-40 threads / 10cm, and the weft density is 20-40 threads / 10cm.

[0023] In one embodiment of the present invention, the thickness of a braiding unit in step (1) is 5-20 mm.

[0024] In one embodiment of the present invention, before the resin transfer molding technology is used to cure in step (2), the three-dimensional orthogonal hybrid preform is first shaped with acetone and then placed in a mold for preheating.

[0025] In one embodiment of the present invention, the resin transfer molding technology in step (2) involves placing a three-dimensional orthogonal hybrid preform in a mold, injecting a resin solution, and then curing it.

[0026] Among them, the fiber volume fraction in the three-dimensional orthogonal woven ablation-resistant thermal insulation composite material is 50-55%;

[0027] The resin solution is obtained by mixing boron-modified phenolic resin, alumina powder, polyacrylamide, and anhydrous ethanol. The mass ratio of boron-modified phenolic resin, alumina powder, polyacrylamide, and water is 30-40:5-10:3-5:100.

[0028] The curing process involves curing at 80℃ for 3 hours, then increasing the temperature to 100℃ for 3 hours, increasing the temperature to 140℃ for 3 hours, increasing the temperature to 180℃ for 3 hours, and finally reducing the temperature to 80℃ for 36 hours.

[0029] The second objective of this invention is to obtain a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material prepared by the method described in this invention.

[0030] The third objective of this invention is the application of the three-dimensional orthogonal woven ablation-resistant thermal insulation composite material described herein in the field of aerospace equipment.

[0031] [Beneficial Effects]

[0032] (1) In the three-dimensional orthogonal woven ablation-resistant heat-insulating composite material prepared by the present invention, the heat insulation layer yarn is made of alumina fiber with excellent heat resistance, which can prevent heat from entering the interior of the material and play a heat insulation role; the load-bearing layer is made of carbon fiber, which can not only bear external loads, but also has excellent high temperature resistance; the normal yarn is made of carbon fiber, and by alternately binding multiple warp and weft yarns, delamination damage can be avoided, and the overall performance of the material can be significantly improved.

[0033] (2) The three-dimensional orthogonal woven ablation-resistant heat insulation composite material prepared by the present invention is injection molded with boron modified phenolic resin with low density and high carbon residue to obtain a low density / ablation-resistant / heat insulation material. The inner and outer layers of the material are divided into load-bearing laminate and heat insulation layer, which meets the requirements of lightweight material and has good ablation resistance and mechanical properties.

[0034] (3) The density of the three-dimensional orthogonal woven ablation-resistant thermal insulation composite material prepared by this invention is 1.2 g / cm³. 3 The following properties are required: tensile strength above 320 MPa, thermal conductivity below 0.31 W / (m·K), and linear ablation rate below 0.025 mm / s. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of a three-dimensional orthogonal hybrid prefabricated structure.

[0036] Figure 2 A side cross-sectional view of the structure of a three-dimensional orthogonal hybrid prefabricated body;

[0037] Among them, 1. warp yarn; 2. weft yarn; 3. normal yarn; 4. carbon fiber; 5. alumina fiber. Detailed Implementation

[0038] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0039] Test method:

[0040] 1. Density test:

[0041] The test was conducted according to GB / T1463-2005 "Test Methods for Density and Relative Density of Fiber Reinforced Plastics".

[0042] 2. Tensile strength test:

[0043] The test was conducted according to GB / T1447 "Test Method for Tensile Properties of Fiber Reinforced Plastics".

[0044] 3. Thermal conductivity testing:

[0045] The test was conducted according to ASTM / E1461-13, "Measuring thermal diffusivity or thermal conductivity by flash method".

[0046] 4. Line ablation rate test:

[0047] The test was conducted according to GJB323B-2018 "Test Method for Ablation of Ablation Materials".

[0048] Raw materials used in the examples:

[0049] Carbon fiber: T700, 800 tex;

[0050] Alumina fiber: Nextel 720, 600 tex;

[0051] Boron-modified phenolic resin: CAS: 9003-35-4, powder, 300 mesh;

[0052] Alumina powder: Powder, 300 mesh.

[0053] Example 1

[0054] A method for preparing a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material includes the following steps:

[0055] (1) Weaving three-dimensional orthogonal hybrid prefabricated structures:

[0056] The warp yarns are placed orthogonally, with a total thickness of 10mm. From top to bottom, they have a three-layer structure: an upper carbon fiber layer, an alumina fiber layer, and a lower carbon fiber layer. The thickness ratio of the upper carbon fiber layer, the alumina fiber layer, and the lower carbon fiber layer is 1:2:1.

[0057] The weft and warp yarns are laid out in perfect alignment; the total thickness is 10mm, and it has a three-layer structure from top to bottom: an upper carbon fiber layer, an alumina fiber layer, and a lower carbon fiber layer. The thickness ratio of the upper carbon fiber layer, the alumina fiber layer, and the lower carbon fiber layer is 1:2:1.

[0058] Carbon fiber is used as the normal yarn;

[0059] Three-dimensional orthogonal weaving is performed, with the warp density controlled at 30 yarns / 10cm and the weft density at 30 yarns / 10cm to form a weaving unit;

[0060] The specific weaving steps are as follows:

[0061] The warp yarns are fed into the loom according to the above requirements. The shedding mechanism drives the yarns to move up and down to form a shed. Then the weft yarns are introduced into the shed and interlaced. Then the normal yarns bind the warp and weft yarns together in a regular and uniform manner to form a weaving unit.

[0062] This process is repeated until the desired size is achieved, resulting in a three-dimensional orthogonal hybrid prefabricated body.

[0063] (2) Composite:

[0064] Boron-modified phenolic resin, alumina powder, polyacrylamide, and anhydrous ethanol were mixed in a mass ratio of 30:5:3:100 and dispersed evenly at 40°C to obtain a resin solution.

[0065] The three-dimensional orthogonal hybrid preform was laid into the composite mold and shaped with acetone. After the composite mold was closed with the top cover plate, it was placed in an oven for preheating at 50°C. Then, the composite mold was removed from the oven, resin solution was injected, and then cured at 80°C for 3 hours, then at 100°C for 3 hours, then at 140°C for 3 hours, then at 180°C for 3 hours, and finally at 80°C for 36 hours. The mixture was then cooled in the oven to obtain a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material with a fiber volume fraction of 55%.

[0066] Comparative Example 1

[0067] Adjust the preform in step (1) of Example 1 as follows:

[0068] Carbon fiber plain weave fabric with a warp density of 30 threads / 10cm and a weft density of 30 threads / 10cm, and alumina plain weave fabric with a warp density of 30 threads / 10cm and a weft density of 30 threads / 10cm, are laid flat to form a preform with a thickness of 10mm, with the thickness ratio of the upper carbon fiber fabric layer, the alumina fiber fabric layer, and the lower carbon fiber fabric layer being 1:2:1.

[0069] Everything else remained the same as in Example 1, resulting in a composite material.

[0070] Comparative Example 2

[0071] The alumina fiber in step (1) of Example 1 is omitted, and carbon fiber is used instead. Everything else is the same as in Example 1 to obtain a composite material.

[0072] Comparative Example 3

[0073] The carbon fiber in step (1) of Example 1 is omitted, and alumina fiber is used instead. Everything else is the same as in Example 1 to obtain a composite material.

[0074] Comparative Example 4

[0075] The arrangement of warp and weft yarns in step (1) of Example 1 is adjusted to be a three-layer structure from top to bottom: upper alumina fiber layer, carbon fiber layer, and alumina fiber layer;

[0076] Everything else remained the same as in Example 1, resulting in a composite material.

[0077] Comparative Example 5

[0078] The normal yarn in step (1) of Example 1 was changed to alumina fiber, while the rest remained the same as in Example 1, to obtain a composite material.

[0079] Comparative Example 6

[0080] The alumina powder in step (2) of Example 1 is omitted, and everything else is kept the same as in Example 1 to obtain the composite material.

[0081] Comparative Example 7

[0082] In step (2) of Example 1, the alumina fiber was changed to silicon nitride fiber, while the rest remained the same as in Example 1, to obtain the composite material.

[0083] Comparative Example 8

[0084] In step (2) of Example 1, the alumina powder was changed to silicon nitride powder, while the rest remained the same as in Example 1, to obtain the composite material.

[0085] The obtained composite material was subjected to performance testing, and the test results are shown in Table 1 below:

[0086] As can be seen from Table 1:

[0087] Compared with Comparative Example 1, replacing the three-layer structure with a fabric in Example 1 results in a decrease in the strength of the composite material.

[0088] Compared with Comparative Example 2, using only carbon fiber in Example 1 results in an excessively high thermal conductivity and poor thermal insulation performance of the composite material.

[0089] Compared with Comparative Example 3, the use of only alumina fibers in Example 1 results in poor mechanical properties of the composite material;

[0090] Compared with Comparative Example 4, the three-layer structure design of Example 1 is different, which leads to poor mechanical properties and poor ablation resistance.

[0091] Compared with Comparative Example 5, Example 1 uses alumina fiber for the normal yarn, which results in a poor binding effect and thus a decrease in mechanical properties.

[0092] Compared with Comparative Example 6, omitting the alumina powder in the resin in Example 1 results in poor ablation resistance;

[0093] Compared with Comparative Example 7, the heat resistance of the material is reduced after the alumina fiber is changed to silicon nitride fiber;

[0094] Compared with Comparative Example 8, changing the alumina powder to silicon nitride powder may result in poor bonding between the preform and the resin, thus reducing mechanical properties.

[0095] Table 1

[0096]

[0097] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material, characterized in that, The steps include the following: (1) Weaving three-dimensional orthogonal hybrid prefabricated body: The orthogonally placed warp yarns have a three-layer structure from top to bottom: an upper carbon fiber layer, an alumina fiber layer, and a lower carbon fiber layer. The thickness ratio of the upper carbon fiber layer, the alumina fiber layer, and the lower carbon fiber layer is 1:2-3:

1. The weft yarns and warp yarns are laid out in a completely consistent and corresponding manner; Carbon fiber is used as the normal yarn; Perform three-dimensional orthogonal weaving to form a weaving unit; then continue to repeat until the desired size is achieved, resulting in a three-dimensional orthogonal hybrid preform. (2) Composite: A three-dimensional orthogonal hybrid preform was cured using resin transfer molding technology to obtain a three-dimensional orthogonal woven ablation-resistant thermal insulation composite material. Among them, resin transfer molding technology involves placing a three-dimensional orthogonal hybrid preform in a mold, injecting a resin solution, and then curing it. The resin solution is obtained by mixing boron-modified phenolic resin, alumina powder, polyacrylamide, and anhydrous ethanol; the mass ratio of boron-modified phenolic resin, alumina powder, polyacrylamide, and water is 30-40:5-10:3-5:

100.

2. The method according to claim 1, characterized in that, In step (1), the carbon fiber is T700 or T800 with a fineness of 600-800 tex.

3. The method according to claim 1, characterized in that, In step (1), the alumina fiber is one or more of Nextel 610, Nextel 720, and ALF-FB3, with a fineness of 600-800 tex.

4. The method according to claim 1, characterized in that, In step (1), the thickness of a single braided unit is 5-20 mm.

5. The method according to claim 1, characterized in that, Before the resin transfer molding technology is used to cure in step (2), acetone is used to shape the three-dimensional orthogonal hybrid preform, and then it is placed in a mold for preheating.

6. The method according to claim 1, characterized in that, The fiber volume fraction in three-dimensional orthogonal woven ablation-resistant thermal insulation composite materials is 50-55%.

7. The three-dimensional orthogonal woven ablation-resistant thermal insulation composite material prepared by the method according to any one of claims 1-6.

8. The application of the three-dimensional orthogonal woven ablation-resistant thermal insulation composite material according to claim 7 in the field of aerospace equipment.

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