CN115477824B - Preparation method of nano-pore resin matrix composite material containing surface layer in-situ authigenic ablation-resistant layer - Google Patents
Preparation method of nano-pore resin matrix composite material containing surface layer in-situ authigenic ablation-resistant layer Download PDFInfo
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- 238000002679 ablation Methods 0.000 title claims abstract description 59
- 229920005989 resin Polymers 0.000 title claims abstract description 58
- 239000011347 resin Substances 0.000 title claims abstract description 58
- 239000010410 layer Substances 0.000 title claims abstract description 51
- 239000002131 composite material Substances 0.000 title claims abstract description 45
- 239000002344 surface layer Substances 0.000 title claims abstract description 45
- 239000011159 matrix material Substances 0.000 title claims abstract description 33
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 27
- 239000011148 porous material Substances 0.000 title claims abstract description 14
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 239000000835 fiber Substances 0.000 claims abstract description 87
- 239000012700 ceramic precursor Substances 0.000 claims abstract description 50
- 238000000034 method Methods 0.000 claims abstract description 24
- 238000001035 drying Methods 0.000 claims abstract description 23
- 239000000919 ceramic Substances 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 238000005245 sintering Methods 0.000 claims abstract description 15
- 238000005470 impregnation Methods 0.000 claims abstract description 11
- 230000008569 process Effects 0.000 claims abstract description 11
- 238000001723 curing Methods 0.000 claims description 27
- 238000005507 spraying Methods 0.000 claims description 27
- 230000010355 oscillation Effects 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 13
- 239000007921 spray Substances 0.000 claims description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 9
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 9
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 239000012454 non-polar solvent Substances 0.000 claims description 9
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 8
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000002798 polar solvent Substances 0.000 claims description 7
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 6
- 239000010453 quartz Substances 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 5
- -1 polysilborazine Polymers 0.000 claims description 5
- 238000003763 carbonization Methods 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 229920001709 polysilazane Polymers 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 3
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 claims description 3
- 229920006282 Phenolic fiber Polymers 0.000 claims description 3
- 239000012298 atmosphere Substances 0.000 claims description 3
- 239000004917 carbon fiber Substances 0.000 claims description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 claims description 3
- 239000004744 fabric Substances 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910052863 mullite Inorganic materials 0.000 claims description 3
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 3
- 229920003257 polycarbosilane Polymers 0.000 claims description 3
- 229920001296 polysiloxane Polymers 0.000 claims description 3
- 238000004321 preservation Methods 0.000 claims description 3
- 238000009941 weaving Methods 0.000 claims 1
- 238000000576 coating method Methods 0.000 abstract description 6
- 239000011248 coating agent Substances 0.000 abstract description 4
- 239000011241 protective layer Substances 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 35
- 230000000052 comparative effect Effects 0.000 description 15
- 238000012360 testing method Methods 0.000 description 9
- 239000000126 substance Substances 0.000 description 5
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 4
- 229920001568 phenolic resin Polymers 0.000 description 4
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- QFXZANXYUCUTQH-UHFFFAOYSA-N ethynol Chemical group OC#C QFXZANXYUCUTQH-UHFFFAOYSA-N 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000805 composite resin Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 239000011151 fibre-reinforced plastic Substances 0.000 description 2
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 239000002296 pyrolytic carbon Substances 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 238000010288 cold spraying Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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- 229920001971 elastomer Polymers 0.000 description 1
- 238000007676 flexural strength test Methods 0.000 description 1
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- 235000010299 hexamethylene tetramine Nutrition 0.000 description 1
- 239000004312 hexamethylene tetramine Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
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- 229920000548 poly(silane) polymer Polymers 0.000 description 1
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- 229920001169 thermoplastic Polymers 0.000 description 1
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- 238000012876 topography Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/02—Fibres or whiskers
- C08K7/04—Fibres or whiskers inorganic
- C08K7/10—Silicon-containing compounds
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
- C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
- C04B35/571—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained from Si-containing polymer precursors or organosilicon monomers
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
- C04B35/589—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride obtained from Si-containing polymer precursors or organosilicon monomers
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/71—Ceramic products containing macroscopic reinforcing agents
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- C04B35/80—Fibres, filaments, whiskers, platelets, or the like
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Abstract
The invention relates to a preparation method of a nano-porous resin matrix composite material containing a surface layer in-situ self-generated ablation-resistant layer, which comprises the following steps: preparing a ceramic precursor solution; pretreating the surface layer of the fiber felt; oscillating sintering, namely converting a ceramic precursor into an ablation-resistant ceramic layer in situ; preparing a resin solution; low pressure impregnation; sol-gel reaction; and (5) drying at normal pressure to obtain the nano-pore resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer. Compared with the composite material without the protective layer, the ablation rate of the composite material with the protective layer is obviously reduced, and the mechanical properties are all improved, so that the ablation resistance of the nano-pore resin matrix composite material can be effectively improved, the reliability of the composite material in extreme environments is improved, and the composite material has wide application prospect in the field of thermal protection. Compared with the existing coating preparation method, the method has the advantages of simple process, low cost, high efficiency, safety, effectiveness and the like.
Description
Technical Field
The invention relates to the field of composite materials, in particular to a preparation method of a nano-pore resin matrix composite material containing a surface layer in-situ self-generated ablation-resistant layer.
Background
The re-entry/entry of an aerospace vehicle into the atmosphere generates severe aerodynamic heating, and the thermal protection system is one of the critical subsystems necessary to ensure proper operation of the aircraft, while the thermal protection material is a critical component of the thermal protection system. With the rapid development of new generation anti-air-defense reverse-approaching hypersonic air-air missiles, the missiles can bear more severe long-time strong oxidation and high dynamic pressure high overload impact, and the thermal protection material becomes a key technical bottleneck for model development. The traditional ablation heat-proof material cannot fully exert the advantages of material ablation heat absorption under the existing thermal environment condition, and has no heat-proof and heat-insulating integrated function due to the fact that the thermal conductivity and density of the material are large, and the heat-proof design adopting the material can cause the structure of the aircraft to be too heavy. Therefore, developing a material with low density, low cost, ultra-long time low micro-ablation and long-acting heat insulation is an important task in the current hypersonic technical field.
The nano-porous resin matrix composite material is a low-density heat-proof integrated composite material which takes fiber as a preform and phenolic resin as a matrix, and has important application in the field of heat protection. However, the low density characteristic brings side effects that when the material is in a high heat flow-low enthalpy-high shear environment, the carbon layer is in a porous loose structure after the surface resin is pyrolyzed, so that the carbon layer is easily mechanically degraded and cannot provide protection for an inner layer matrix, and particularly in the process of re-entering the tail end after long-time heating, the airflow shearing is increased rapidly, and the surface layer of the material is degraded seriously. The direct protection of the material erosion surface by the coating method is the most direct and effective method, but for the ablation of the heat-resistant material, the traditional coating method has complex process and higher cost, and the coating is easy to fail at high temperature due to the generally poor heat matching performance of the coating and the matrix. And the anti-ablation modification by integrally dipping the ceramic precursor into the fiber preform can obviously improve the density and the heat conductivity of the material and influence the heat insulation performance of the material.
Disclosure of Invention
The invention aims to overcome at least one of the defects in the prior art and provide a preparation method of the nano-pore resin matrix composite material containing the surface layer in-situ self-generated anti-ablation layer, which can effectively improve the anti-ablation and anti-scouring performance of the nano-pore resin matrix composite material in a ballistic environment.
The aim of the invention can be achieved by the following technical scheme:
the preparation method of the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer comprises the following steps:
preparing a ceramic precursor solution: dissolving a ceramic precursor in a nonpolar solvent to obtain a ceramic precursor solution;
surface pretreatment of fiber mats: uniformly spraying the ceramic precursor solution on the surface layer of the fiber mat, and then drying and curing;
and (3) oscillating and sintering: placing the pretreated fiber mat into a carbonization furnace, sintering the fiber mat in inert atmosphere, and converting a ceramic precursor into an ablation-resistant ceramic layer in situ;
preparing a resin solution: dissolving resin by a polar solvent and adding a curing agent to obtain a resin solution;
low pressure impregnation: placing the fiber felt after oscillation sintering in a mould, and completely impregnating the fiber felt with a resin solution;
sol-gel reaction: sealing the mold, performing sol-gel reaction, and cooling to room temperature after the reaction is finished to obtain a composite material;
and (3) drying under normal pressure: and opening the mould, and then drying the composite material in a normal pressure environment to obtain the nano-pore resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer.
Further, the ceramic precursor comprises one or more of polycarbosilane, polysilazane, polysiloxane and metal polysilazane, and the nonpolar solvent comprises one or more of n-hexane, n-heptane, cyclohexane or toluene.
Further, the mass fraction of the ceramic precursor in the ceramic precursor solution is 25-100wt% and the mass fraction of the nonpolar solvent is 0-75wt%.
Further, the fiber felt comprises a fiber felt woven by one or more of carbon fiber, quartz fiber, mullite fiber, phenolic fiber or polyacrylonitrile fiber.
Further, the structural shape of the fiber feltComprises a quasi-three-dimensional needled structure, a fiber cloth layered structure, a needled fiber felt structure or a 2.5D woven structure, wherein the density of the fiber felt is 0.1-0.5g/cm 3 The thickness is 10-30mm.
Further, the curing temperature of the ceramic precursor is 50-100 ℃ and the curing time is 6-48h.
Further, the spraying method is a multi-time quantitative spraying-drying-curing process; the single spraying ceramic precursor solution is 30-50ml, and the total spraying amount is 90-150ml.
Further, during spraying, the spray gun is perpendicular to the surface of the fiber felt, the spraying pressure is 0.1-0.3MPa, the spraying height is 100-200mm, and the moving speed of the spray nozzle is 10-12cm/s.
Further, the basic heating rate of the oscillation heating sintering is 10 ℃/min, the oscillation amplitude is +/-5 ℃/min, the oscillation frequency is 1/15-1/60Hz, the heat preservation time of each oscillation is 1-10min, and the end point temperature is 450-550 ℃.
Further, the polar solvent comprises one or more of n-butanol, isopropanol, ethanol or ethylene glycol; the temperature of the sol-gel reaction is 80-140 ℃ and the time is 24-48h; the drying temperature is 20-120 ℃ and the drying time is 24-48h.
Compared with the prior art, the invention has the following advantages:
(1) In the invention, the cold spraying method sprays the ceramic precursor on the surface layer of the fiber preform and generates the ablation-resistant layer in situ, the raw materials are easy to obtain, the preparation conditions are not limited, and the nano pore structure of the material is not needed to be excessively relied on;
(2) In the invention, the surface layer can be uniformly distributed with ceramic components and the thickness is controllable by a plurality of quantitative spraying, drying and curing processes, and the phenomenon of surface large-scale cracking can be avoided;
(3) In the invention, the oscillation heating sintering is carried out, the heating rate is controlled to float up and down with a certain amplitude and frequency on the basic heating rate, so that the ceramic precursor is fully pyrolyzed, the anti-ablation ceramic layer is generated in situ on the surface layer of the fiber preform, and meanwhile, the cracking and falling off caused by overlarge heating rate in the main weightless temperature range are avoided;
(4) In the invention, the ceramic layer is tightly adhered with the surface fibers of the fiber felt, so that on one hand, the strong shearing erosion of heat flow is effectively resisted, the pyrolytic carbon layer is protected, and on the other hand, the warping and falling of the ablation-resistant layer in the heating process caused by poor heat matching performance between the resin matrix and the ceramic precursor are avoided;
(5) Compared with the whole impregnation pretreatment fiber preform, the method only generates the ceramic ablation layer in situ on the surface layer of the fiber preform, thereby avoiding affecting the interface bonding strength of the fiber and the resin matrix and affecting the mechanical property of the material;
(6) In the invention, the surface layer in-situ self-generated anti-ablation ceramic layer presents a flaky ladder-shaped distribution among surface layer fibers, is not a simple single-layer structure, has better anti-ablation effect, and does not influence the impregnation of resin.
Drawings
FIG. 1 is a surface view of the surface ablation resistant layer of the fiber mat preform of example 1;
FIG. 2 is an SEM image of the surface layer of the fiber after pretreatment of the fiber mat in example 1;
FIG. 3 is a topography of the composite skin of example 1;
FIG. 4 is a SEM image of a cross-section of an ablation-resistant layer of a composite surface layer according to example 1.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.
The preparation method of the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer comprises the following steps:
preparing a ceramic precursor solution: dissolving a ceramic precursor in a nonpolar solvent to obtain a ceramic precursor solution; the ceramic precursor comprises one or more of polycarbosilane, polysilabozane, polysilazane, polysiloxane and metal polysilane, and the nonpolar solvent comprises one or more of n-hexane, n-heptane, cyclohexane and toluene. The mass fraction of the ceramic precursor in the ceramic precursor solution is 25-100wt% and the mass fraction of the nonpolar solvent is 0-75wt%.
Surface pretreatment of fiber mats: injecting the ceramic precursor solution into a spray gun, uniformly spraying on the surface layer of the fiber felt, drying and curing in an oven for a period of time, taking out, and repeating the operation for three times; the fiber felt comprises fiber felt woven by one or more of carbon fiber, quartz fiber, mullite fiber, phenolic fiber or polyacrylonitrile fiber, and the structural form of the fiber comprises: a quasi-three-dimensional needled structure, a fiber cloth layered structure, a needled fiber felt structure or a 2.5D woven structure, wherein the density of the preform is 0.1-0.5g/cm 3 The thickness is 10-30mm. The curing temperature of the ceramic precursor is 50-100 ℃ and the curing time is 6-48h. The spraying method is a multiple quantitative spraying-drying-curing process. The single spraying ceramic precursor solution is 30-50ml, and the total spraying amount is 90-150ml. The spray gun is perpendicular to the surface of the fiber preform, the spraying pressure is 0.1-0.3MPa, the spraying height is 100-200mm, and the moving speed of the spray nozzle is 10-12cm/s.
And (3) oscillating and sintering: placing the pretreated fiber mat into a carbonization furnace, sintering the fiber mat in a nitrogen atmosphere, and converting a ceramic precursor into an ablation-resistant ceramic layer in situ; the basic heating rate of oscillation heating sintering is 10 ℃/min, the oscillation amplitude is +/-5 ℃/min, the oscillation frequency is 1/15-1/60Hz, the time of each oscillation heat preservation is 1-10min, and the end temperature is 450-550 ℃.
Preparing a resin solution: dissolving resin by a polar solvent and adding a curing agent to obtain a resin solution; the polar solvent is one or more of n-butanol, isopropanol, ethanol or ethylene glycol;
low pressure impregnation: placing the pretreated fiber mat in a proper mold, and completely impregnating the preform with a resin solution;
sol-gel reaction: sealing the mold, performing sol-gel reaction, and cooling to room temperature after the reaction is finished to obtain a composite material; the temperature of the sol-gel reaction is 80-140 ℃ and the time is 24-48h;
and (3) drying under normal pressure: and opening the mould, and then drying the composite material in an atmospheric environment to obtain the nano-pore resin matrix composite material surface anti-ablation layer. The drying temperature is 20-120 ℃ and the drying time is 24-48h.
Example 1
The preparation method of the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer comprises the following steps:
1. preparing a ceramic precursor solution: diluting the ceramic precursor in n-hexane to obtain a ceramic precursor solution with the concentration of 25 wt%;
2. quantitative spraying-drying-curing for a plurality of times: taking density of 0.26g/cm 3 And (3) vertically spraying a ceramic precursor solution on the surface layer of the quartz fiber felt by using a spray gun, drying and curing in a 100 ℃ oven for 6 hours, and taking out, wherein the specific spraying parameters are as follows: the spraying amount is 90ml/s, the spraying distance is 200mm, the spraying pressure is 0.2MPa, and the moving speed of the nozzle is 12cm/s. Repeating the spraying-drying-curing operation three times, wherein the volume density of the fiber is 0.29g/cm 3 。
3. And (3) oscillating and sintering: placing the fiber preform pretreated in the step 2 into a carbonization furnace, and sintering under nitrogen atmosphere, wherein the specific oscillation heating program is controlled as follows: keeping the temperature at 10 ℃/min to 100 ℃ for 10min; keeping the temperature at 15 ℃/min to 250 ℃ for 10min; keeping the temperature at 10 ℃/min to 350 ℃ for 10min; preserving heat for 10min at 5 ℃/min to 400 ℃; keeping the temperature at 10 ℃/min to 500 ℃ for 30min; and then cooling to room temperature at 10 ℃ per minute to obtain the fiber preform with the surface anti-ablation layer.
4. Preparing a resin solution: dissolving phenolic resin by using a polar solvent isopropanol and adding a curing agent hexamethylenetetramine with the mass of 14% of the resin to obtain a resin solution with the concentration of 30 wt%;
5. low pressure impregnation: placing the quartz fiber preform with the surface anti-ablation layer in a mold, and completely impregnating the quartz fiber felt with a resin solution, wherein the impregnation pressure is 0.05MPa;
6. sol-gel reaction: sealing the mould, performing sol-gel reaction at 80 ℃, and cooling to room temperature after 48 hours of reaction to obtain a composite material;
7. and (3) drying under normal pressure: and opening the mould, and then drying the composite material for 48 hours in the environment of normal temperature and normal pressure to obtain the nano-pore resin matrix composite material surface anti-ablation layer.
Example 2
The difference from example 1 is that the concentration of the ceramic precursor solution in step 1 is 50wt%.
Example 3
The difference from example 1 is that the concentration of the ceramic precursor solution in step 1 is 75wt%.
Example 4
The difference from example 1 is that the concentration of the ceramic precursor solution in step 1 is 100wt%.
Example 5
The difference from example 1 is that the drying curing temperature in step 1 is 75℃and the curing time is 12 hours.
Example 6
The difference from example 1 is that the drying curing temperature in step 1 is 50℃and the curing time is 24 hours.
Comparative example 1
The difference from example 1 is that there is no step 1, and the fiber preform in step 3 is a silica fiber mat which has not been surface layer-ceramifiable pretreatment, and has a density of 0.26g/cm 3 The size is 220×220×10mm.
Comparative example 2
The difference from example 1 is that the fiber preform is pretreated in step 1 by immersing the entire fiber preform in a 5wt% ceramic precursor solution for 1 hour.
Comparative example 3
The difference from example 1 is that the fiber preform is pretreated in step 1 with a single spray-cure, the total amount of single spray being the same as the total amount of three sprays in example 1.
The phenolic resin in all examples and comparative examples is a commercially available thermoplastic phenolic resin, and specific sources are, for example, the chemical industry of micronaire in atanan, futai rubber in Dongguan, the chemical industry of star in Nantong, the chemical industry of cushing She Hao, and the like.
All examples and comparative examples were subjected to oxyacetylene test, flexural strength test and compressive strength test, and the results are shown in table 1 below.
Oxyacetylene test: oxyacetylene ablation test with GJB 323A-1996 (2000 ℃ C. And 4.2MW/m 2 )；
Tensile strength test: the tensile strength of the material is tested by using an electronic universal testing machine Metts CMT4204, and the tensile property testing method standard GB/T1447-2005 of fiber reinforced plastics is adopted;
compression strength test: compression strength of the material in the Z-axis direction (thickness direction) is tested by adopting an electronic universal testing machine Meite CMT4204, and standard GB/T1448-2005 of a fiber reinforced plastic compression performance test method is adopted.
TABLE 1
| Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 | Comparative example 1 | Comparative example 2 | Comparative example 3 | |
| Density/g.cm -3 | 0.66 | 0.65 | 0.66 | 0.67 | 0.69 | 0.64 | 0.66 | 0.67 | 0.66 |
| Ceramic precursor solution concentration/% | 25 | 50 | 75 | 100 | 25 | 25 | 25 | 5 | 25 |
| Pretreatment curing temperature/. Degree.C | 50 | 50 | 50 | 50 | 75 | 100 | / | 50 | 50 |
| Pretreatment curing time/h | 48 | 48 | 48 | 48 | 24 | 6 | / | 48 | 48 |
| Linear ablation rate/mm.s -1 | 0.138 | 0.135 | 0.130 | 0.148 | 0.136 | 0.135 | 0.155 | 0.148 | 0.142 |
| Mass ablation rate/mg.s -1 | 24.3 | 25.1 | 26.3 | 27.5 | 24.3 | 24.1 | 28.1 | 26.5 | 25.3 |
| Back temperature rise/°c | 61 | 65 | 72 | 98 | 63 | 62 | 40 | 26 | 63 |
| Tensile Strength/MPa | 62 | 68 | 67 | 70 | 63 | 61 | 63 | 57 | 61 |
| Compressive Strength/MPa | 224 | 250 | 248 | 244 | 223 | 226 | 229 | 204 | 228 |
In the embodiment 1, the surface diagram of the ablation-resistant layer on the surface layer of the fiber preform is shown in fig. 1, after pretreatment, gaps among fibers of the surface layer of the preform are filled with the ceramic precursor, and the gaps are uniformly distributed, which shows that the process of pretreating the fiber preform by spraying, drying and curing for multiple times can well avoid uneven local ablation resistance caused by overlarge single spraying amount (for example, comparative example 3). In the embodiment 1, the morphology of the surface layer of the composite material is shown in fig. 3, the surface layer of the material presents grid lines, but the surface layer does not have large-scale cracks, because the surface layer fibers and the resin are separated by a ceramic sheet layer in the process of impregnating the resin, the outermost thin resin layer is not supported by the fibers, and the volume shrinkage of the resin layer is larger when the material is dried, so that grid cracks shown in fig. 3 appear. The SEM image of the cross section of the ablation-resistant layer of the surface layer in example 1 is shown in fig. 4, and the microscopic morphology is complete and has no cracks, which shows that the surface ceramic layer and the resin matrix are mutually filled without influencing the impregnation of the resin.
Compared with comparative example 1, the linear ablation rate and the mass ablation rate of examples 1-4 both show a tendency of descending first and ascending later, because the surface anti-ablation ceramic layer has a good supporting effect, the surface hardness of the material is increased, the resin and pyrolytic carbon are prevented from being mechanically degraded, the resin better plays the ablation heat-proof effect, and the ablation rate is reduced. However, the excessive concentration of the precursor can lead to the reduction of the resin content of the surface layer of the composite material, the ablation heat-resistant function is damaged, the internal temperature rise of the material is quicker, and the inner layer resin matrix is rapidly oxidized, so that the ablation rate is increased instead. The tensile and compressive strength of examples 1-4 were slightly increased compared to comparative example 1 because the ceramic layer bonded adjacent fibers together in a flake form effectively increased the stiffness of the preform surface layer fibers, thereby increasing the mechanical strength of the material, as shown in SEM images of the pretreated fiber surface layer in example 1, fig. 2.
Examples 1-4 compared to comparative example 2 demonstrate that the overall impregnation of the pretreated fiber preform reduces the mechanical strength of the composite because the untreated fiber surface has a large number of reactive groups such as hydroxyl groups that are capable of forming stable chemical bonds with the resin and the interfacial strength between the fiber and the resin matrix is high. After the whole dipping pretreatment, the surface active groups are covered by the ceramic precursor, the interface bonding strength between the fiber preform and the resin matrix is reduced, and the mechanical property of the material is reduced, so that the method for spraying the ceramic precursor in-situ authigene ceramic layer on the surface layer of the fiber preform is further shown, the whole interface bonding strength of the material is not influenced, the ablation resistance is improved, and meanwhile, the mechanical stability of the material is ensured. However, examples 1 to 4 have a higher back temperature than comparative example 2 because comparative example 2 uses an overall impregnation pretreatment fiber reinforcement, only a thinner ceramic layer is attached to the surface of the fiber, and a denser ceramic layer does not exist on the surface layer of the material, so that the overall nano-pore structure of the material is not affected, and the heat insulation performance of the material is not greatly affected.
Examples 1-4, compared to comparative example 1, although the material density was nearly the same, the back temperature increased as the concentration of the ceramic precursor increased, because the unique porous structure of the nanoporous resin-based composite material effectively reduced the thermal conductivity of the material, and the radiative heat transfer of the material was negligible at room temperature, as the concentration of the ceramic precursor increased, the ceramic component content in the surface layer of the material increased, reducing the resin matrix content, while the thickness direction (Z direction) fibers were "bridged" by the ceramic component, improving the solid state thermal conduction in that direction, and thus the thermal conductivity of the material as a whole.
Compared with the composite material without the protective layer, the ablation rate of the composite material with the protective layer is obviously reduced, and the mechanical properties are all improved, so that the ablation resistant layer can effectively improve the ablation resistance of the nano-pore resin-based composite material, the reliability of the material in extreme environments is improved, and the composite material has wide application prospect in the field of thermal protection. Compared with the existing coating preparation method, the method has the advantages of simple process, low cost, high efficiency, safety, effectiveness and the like.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the invention in any way, and any person skilled in the art may make modifications or alterations to the disclosed technical content to the equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (7)
1. The preparation method of the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer is characterized by comprising the following steps:
preparing a ceramic precursor solution: dissolving a ceramic precursor in a nonpolar solvent to obtain a ceramic precursor solution;
surface pretreatment of fiber mats: uniformly spraying the ceramic precursor solution on the surface layer of the fiber mat, and then drying and curing;
and (3) oscillating and sintering: placing the pretreated fiber mat into a carbonization furnace, sintering the fiber mat in inert atmosphere, and converting a ceramic precursor into an ablation-resistant ceramic layer in situ;
preparing a resin solution: dissolving resin by a polar solvent and adding a curing agent to obtain a resin solution;
low pressure impregnation: placing the fiber felt after oscillation sintering in a mould, and completely impregnating the fiber felt with a resin solution;
sol-gel reaction: sealing the mold, performing sol-gel reaction, and cooling to room temperature after the reaction is finished to obtain a composite material;
and (3) drying under normal pressure: opening the mould, and then drying the composite material in a normal pressure environment to obtain a nano-pore resin matrix composite material containing a surface layer in-situ self-generated ablation-resistant layer;
the spraying method is a multiple quantitative spraying-drying-curing process; the ceramic precursor solution sprayed once is 30-50ml, and the total sprayed amount is 90-150ml;
when spraying, the spray gun is vertical to the surface of the fiber felt, the spraying pressure is 0.1-0.3MPa, the spraying height is 100-200mm, and the moving speed of the spray nozzle is 10-12cm/s;
the basic heating rate of the oscillation heating sintering is 10 ℃/min, the oscillation amplitude is +/-5 ℃/min, the oscillation frequency is 1/15-1/60Hz, the heat preservation time of each oscillation is 1-10min, and the end temperature is 450-550 ℃.
2. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer according to claim 1, wherein the ceramic precursor comprises one or more of polycarbosilane, polysilborazine, polysilazane, polysiloxane and metal polysilocarane, and the nonpolar solvent comprises one or more of n-hexane, n-heptane, cyclohexane and toluene.
3. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer, which is disclosed in claim 1, is characterized in that the mass fraction of the ceramic precursor in the ceramic precursor solution is 25-100wt%, and the mass fraction of the nonpolar solvent is 0-75wt%.
4. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer according to claim 1, wherein the fiber felt comprises a fiber felt woven by one or more of carbon fibers, quartz fibers, mullite fibers, phenolic fibers and polyacrylonitrile fibers.
5. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer according to claim 1, wherein the structural form of the fiber mat comprises a quasi-three-dimensional needling structure, a fiber cloth layering structure, a needled fiber mat structure or a 2.5D weaving structure, and the density of the fiber mat is 0.1-0.5g/cm 3 The thickness is 10-30mm.
6. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer according to claim 1, wherein the curing temperature of the ceramic precursor is 50-100 ℃ and the curing time is 6-48h.
7. The method for preparing the nano-porous resin matrix composite material containing the surface layer in-situ self-generated ablation-resistant layer according to claim 1, wherein the polar solvent comprises one or more of n-butanol, isopropanol, ethanol or ethylene glycol; the temperature of the sol-gel reaction is 80-140 ℃ and the time is 24-48h; the drying temperature is 20-120 ℃ and the drying time is 24-48h.
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