A resin-based heat-resistant composite material with a surface-coated low-temperature curing and high-temperature infrared stealth coating and a preparation method thereof

Abstract

The present invention relates to the technical field of high-temperature infrared stealth resin matrix composites, and specifically discloses a resin matrix heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating, which sequentially includes a resin matrix heat-resistant composite material and a high-temperature infrared stealth coating from the inside to the outside. The high-temperature infrared stealth coating uses nano-metal and flaky metal powders as low-emissivity fillers, and glass phase and organic resin as bonding phases. The composite material preparation method in the present invention has the characteristics of low cost and low energy consumption, and reduces the damage to the resin matrix heat-resistant composite material. The high-temperature infrared stealth coating on the surface of the composite material has a wide temperature range of low emissivity and high bonding characteristics, avoiding the shedding and peeling of the high-temperature infrared stealth coating due to the decomposition of the composite material in the use environment, and solving the stealth problem of the aircraft in a wide temperature range.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature infrared stealth resin-based composite materials, and particularly relates to a resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating and a preparation method thereof. Background Art

[0002] When a high-speed aircraft is flying at high speed, the air around the aircraft is strongly compressed and severely rubbed. Most of the kinetic energy of the aircraft is converted into heat energy, resulting in a sharp increase in the air temperature around the aircraft, forming an aerodynamic heating flow field with high temperature, high pressure, and high heat flux. Therefore, the heat protection problem is one of the key problems that must be solved for high-speed aircraft. On the other hand, aerodynamic heating causes the surface of the aircraft to have a relatively high temperature, and the infrared exposure characteristics are prominent, making the aircraft seriously threatened by infrared detection and guidance weapon equipment. The infrared stealth problem is another key problem that must be solved for high-speed aircraft.

[0003] Resin-based heat-resistant composite materials are a type of composite materials that are widely used in the heat protection system of high-speed aircraft at present. On the one hand, a large amount of heat is carried away through mechanisms such as decomposition and carbonization of the resin-based heat-resistant composite materials in a thermal environment, playing a role in heat insulation; on the other hand, by coating a high-temperature infrared stealth coating on the surface of the resin-based heat-resistant composite materials, the infrared radiation characteristics can be significantly reduced, playing a role in infrared stealth. Coating a high-temperature infrared stealth coating on the resin-based heat-resistant composite materials needs to meet the following conditions: First, the infrared stealth coating has a low emissivity in a wide temperature range and can still firmly adhere to the material surface without falling off when the composite material decomposes at high temperature; second, the construction process is simple and should have the characteristics of low cost and low energy consumption; third, the high-temperature infrared stealth coating should have the characteristics of low-temperature curing to prevent the decomposition of the resin-based heat-resistant composite materials caused by high-temperature treatment. Chinese Patent with Publication No. CN112920442A discloses a resin-based heat-resistant composite material with a surface coated with a high-temperature infrared stealth coating and a preparation method thereof, which is dried and cured at 120-150°C, causing too much damage to some resin-based composite material systems; after the resin-based heat-resistant composite material with a surface coated with a high-temperature infrared stealth coating is subjected to a thermal shock test at 800°C for 10 minutes, there are basically no obvious cracking, peeling and other phenomena, and the infrared emissivity of the coating does not change significantly after the test, but it can be seen from the coating photos after the test that there is a small amount of peeling of the coating after the test, and the high-temperature bonding performance between the coating and the resin-based heat-resistant composite material needs to be further improved. Summary of the Invention

[0004] Aiming at the above deficiencies, the present invention provides a resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating and a preparation method thereof. The composite material has the advantages of low infrared emissivity in a wide temperature range, high bonding performance between the coating and the substrate in a wide temperature range, excellent high-temperature resistance, etc. The specific technical solutions are as follows:

[0005] A resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, which sequentially includes a resin-based heat-resistant composite material and a high-temperature infrared stealth coating from inside to outside. The high-temperature infrared stealth coating is composed of a low-emissivity filler and a binder phase. The low-emissivity filler is a mixed filler composed of nano silver powder or nano silver-palladium powder and flaky aluminum powder. The binder phase is composed of a glass phase and an organic resin.

[0006] Preferably, in the above-mentioned resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, the mass fraction of the low-emissivity filler in the coating is 80% - 95%, the mass fraction of nano silver or nano silver-palladium powder in the mixed filler is 10% - 90%, and the mass fraction of flaky aluminum powder is 10% - 90%; the mass fraction of palladium in the nano silver-palladium powder is 5% - 30%, and the mass fraction of nano silver is 70% - 95%; the particle size of the nano silver and palladium powder is 30nm - 150nm, and the particle size of the flaky aluminum powder is 5μm - 40μm.

[0007] Preferably, in the above-mentioned resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, the mass content of the organic resin in the binder phase is 5% - 10%, and the mass content of the glass phase is 90 - 95%. The organic resin is one of epoxy resin, acrylic resin, epoxy-modified silicone resin, and fluororesin; the glass phase is a lead-containing low-melting-point glass, and the main components are PbO - B2O3, where the mass fraction of PbO is 1% - 30%, the mass fraction of B2O3 is 20% - 80%, and the softening point temperature is 350°C - 400°C. Adding an organic resin to the binder phase is beneficial for low-temperature curing, achieving low infrared emissivity, and improving the bonding property between the coating and the substrate; the content of the organic resin needs to be controlled within a certain range. If the content of the organic resin is too high, it will affect the infrared stealth performance and will decompose severely during high-temperature use, resulting in coating peeling. If the content is too low, it will affect the film formation of the coating.

[0008] Preferably, in the above-mentioned resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, the reinforcement of the resin-based heat-resistant composite material is one of carbon fiber, glass fiber, high-silica fiber, aramid fiber, and quartz fiber, and the resin matrix is one of epoxy resin, phenolic resin, benzoxazine resin, arylacetylene resin, and silicon arylacetylene resin; the weaving form of the reinforcement is one of three-dimensional five-directional fabric, 2.5D fabric, stitched fabric, and needle-punched fabric; the density of the resin-based heat-resistant composite material is 0.5g / cm 3 ~1.5g / cm 3 .

[0009] Preferably, in the above-mentioned resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, the thickness of the high-temperature infrared stealth coating is 10μm - 200μm.

[0010] A preparation method of a resin-based heat-resistant composite material with a surface-coated low-temperature-curing and high-temperature infrared stealth coating, comprising the following steps:

[0011] (1) Prepare the resin-based heat-resistant composite material;

[0012] (2) Grind and roughen the surface of the resin-based heat-resistant composite material to be coated;

[0013] (3) Apply the high-temperature infrared stealth coating to the surface of the resin-based heat-resistant composite material by brushing or normal-temperature spraying, and after low-temperature curing and polishing, the low-temperature curing process parameters are: the temperature is 70°C to 100°C, and the time is 1h to 2h, to obtain the high-temperature infrared stealth coating.

[0014] Preferably, in the above preparation method, in step (1), it includes cleaning the mold, applying a release agent on the surface of the mold to complete the mold treatment; assembling the resin-based composite material fabric with the mold and performing an airtightness inspection; injecting the liquid resin into the closed mold cavity by pressure to complete the infiltration of the resin-based composite material fabric, and obtaining the resin-based heat-resistant composite material through heating and curing and demolding.

[0015] Preferably, in the above preparation method, the infiltration pressure is 0.2 MPa to 1.2 MPa; the viscosity of the liquid resin is 20 mPa·s to 600 mPa·s; the heating and curing temperature is 50°C to 280°C, and the curing time is 2h to 40h.

[0016] Preferably, in the above preparation method, the high-temperature infrared stealth coating mainly consists of a low-emissivity filler, a binder, and an organic carrier; the binder consists of glass powder and an organic resin. The high-temperature infrared stealth coating is prepared by the following method: passing the glass powder after melting, water cooling, and ball milling through a 200-400 mesh sieve, then mixing the glass powder and the low-emissivity filler evenly with a planetary gravity mixer, and then mixing evenly with the organic resin and the organic carrier, and grinding with a three-roll grinder to obtain the high-temperature infrared stealth coating.

[0017] Preferably, in the above preparation method, the organic carrier mainly consists of 70% to 80% by mass of butyl carbitol, 8% to 12% of tributyl citrate, 2% to 5% of ethyl cellulose, 2% to 5% of Span-85, and 3% to 6% of 1,4-butyrolactone, and the mass fraction of the organic carrier in the high-temperature infrared stealth coating is 5% to 25%.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The resin-based heat-resistant composite material with a surface-coated high-temperature infrared stealth coating adopts a high-temperature infrared stealth coating system with a mixed powder of nano-metal and flaky metal with low emissivity characteristics as the filler, and an organic resin with low-temperature curing characteristics and low-melting-point glass as the bonding phase. The flaky metal powder in this coating has good coverage and can quickly cure into a film at low temperature to achieve low emissivity. In addition, the nano-scale metal powder in this coating has high sintering activity and can quickly sinter in a high-temperature environment, and also has low emissivity characteristics at high temperature, so that low emissivity in a wide temperature range can be achieved, solving the stealth problem of the aircraft in a wide temperature range.

[0020] 2. The high-temperature infrared stealth coating of the present invention uses an organic resin and low-melting-point glass as a mixed bonding phase. The organic resin in this coating is responsible for bonding the low-emissivity filler in the low-temperature region, so that the coating adheres to the surface of the composite material. In a high-temperature use environment, the organic resin decomposes, and the glass phase can quickly melt and provide bonding in the high-temperature region together with the sintering characteristics of the metal powder, so that the low-emissivity filler can firmly adhere to the surface of the resin-based composite material, avoiding the peeling and stripping of the high-temperature infrared stealth coating due to the decomposition of the composite material in the use environment, thereby maintaining the infrared stealth function of the aircraft.

[0021] 3. In the composite material preparation method of the present invention, a low-temperature curing process is adopted, which has low energy consumption and reduces damage to the resin-based heat-resistant composite material.

[0022] 4. A relatively simple coating application process is adopted in the present invention. The process and equipment are simple, large components can be prepared, and it is suitable for large-scale industrial production. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a photo of the resin-based heat-resistant composite material after grinding and roughening treatment in Embodiment 1 of the present invention.

[0025] Figure 2 It is a photo of the high-temperature infrared stealth coating prepared in Embodiment 1 of the present invention.

[0026] Figure 3 It is a photo of the resin-based heat-resistant composite material with a surface-coated high-temperature infrared stealth coating after heat inspection at 600°C - 10 min and 1000°C - 10 min in Embodiment 1 of the present invention.

[0027] Figure 4This is a photo of the resin-based heat-resistant composite material with a high-temperature infrared stealth coating on its surface after being thermally tested by a quartz lamp in Example 1 of the present invention. Detailed Embodiments

[0028] The following provides a detailed description of the specific embodiments of the present invention. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Unless otherwise defined, all the professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0029] Example 1

[0030] A resin-based heat-resistant composite material with a low-temperature curing high-temperature infrared stealth coating, which consists of a resin-based heat-resistant composite material and a high-temperature infrared stealth coating from the inside to the outside. The resin-based heat-resistant composite material uses quartz fiber as the reinforcement and phenolic resin as the resin matrix. The weaving form of the reinforcement is 2.5D fabric, and the density of the resin-based heat-resistant composite material is 0.65 g / cm 3 . The high-temperature infrared stealth coating consists of a low-emissivity filler and a binder phase. The mass fraction of the low-emissivity filler in the high-temperature infrared stealth coating is 90%, which is composed of a mixed filler of 56% by mass of nano silver powder and 44% by mass of flaky aluminum powder. The particle size of the nano silver is 50 nm, and the particle size of the flaky aluminum powder is 30 μm; the binder phase consists of 90% by mass of PbO-B2O3 glass phase and 10% by mass of bisphenol A epoxy resin. The mass fraction of PbO in the PbO-B2O3 glass phase is 21%, and the mass fraction of B2O3 is 79%. The glass softening point temperature is 350 °C, and the thickness of the high-temperature infrared stealth coating is 100 μm.

[0031] This example also provides a preparation method for the resin-based heat-resistant composite material with a high-temperature infrared stealth coating on its surface, including the following steps:

[0032] (1) Clean the mold, apply a release agent on the surface of the mold, and complete the mold treatment;

[0033] (2) Assemble the resin-based composite fabric with the mold and conduct an airtightness inspection;

[0034] (3) Inject liquid phenolic resin with a viscosity of 50 mPa·s into the closed mold cavity under a pressure of 0.4 MPa to complete the infiltration of the resin-based composite fabric. Heat and cure at 80 °C for 36 h, and then remove the mold to complete the preparation of the resin-based heat-resistant composite material;

[0035] (4) The surface of the resin-based thermal protection composite material to be coated is polished and roughened. The resin-based thermal protection composite material after the polishing and roughening treatment is as Figure 1 shown;

[0036] (5) The high-temperature infrared stealth coating is coated on the surface of the resin-based thermal protection composite material by brushing process, cured at 70 °C for 2 h, and the high-temperature infrared stealth coating is prepared after polishing treatment (see Figure 2 ).

[0037] Among them, in step (5), the high-temperature infrared stealth coating is prepared by the following method: the glass powder after melting and ball milling is sieved through a 200-400 mesh sieve, and then the glass powder, nano-silver powder, and flaky aluminum powder are mixed evenly, and finally mixed evenly with bisphenol A epoxy resin and organic carrier and ground to obtain the high-temperature infrared stealth coating. The organic carrier in the high-temperature infrared stealth coating is mainly composed of 80% by mass of butyl carbitol, 10% of tributyl citrate, 3% of ethyl cellulose, 3% of Span-85 and 4% of 1,4-butyrolactone, and the mass fraction of the organic carrier in the high-temperature infrared stealth coating is 20%.

[0038] The high-temperature infrared stealth coating prepared in this example has good bonding with the surface of the resin-based thermal protection composite material. Referring to the standard GB9286-1998 for the coating adhesion test, the coating without peeling after sticking is grade 0, and the adhesion is qualified. Figure 3 The photograph shows the resin-based thermal protection composite material with a high-temperature infrared stealth coating on the surface after 600 °C - 10 min and 1000 °C - 10 min thermal assessments, Figure 4 The photograph shows the resin-based thermal protection composite material with a high-temperature infrared stealth coating on the surface after being tested by a quartz lamp. It can be seen from the photograph that the high-temperature infrared stealth coating is intact without cracking, peeling and other phenomena. The measured normal temperature infrared emissivities at 3-5 μm in the original state of the coating (before assessment), after 600 °C thermal assessment, after 1000 °C thermal assessment, and after quartz lamp assessment (the hottest heat flux is 150 kW / m 2 , the assessment time is 600 s) are 0.23, 0.10, 0.13 and 0.13 respectively. The infrared emissivity of the high-temperature infrared stealth coating decreases significantly after thermal assessment, indicating that the high-temperature infrared stealth coating prepared on the surface of the resin-based thermal protection composite material exhibits the characteristics of wide temperature range and low emissivity, excellent heat resistance, and strong high-temperature bonding with the substrate.

[0039] Comparative Example 1

[0040] The difference between this comparative example and Example 1 is that the low-emissivity filler is nano-silver powder with a particle size of 50 nm; other components and preparation methods are the same as those in Example 1.

[0041] The coating prepared in this comparative example has good bonding with the surface of the resin-based thermal protection composite material. After gluing, the coating has no peeling, which is grade 0, and the adhesion is qualified. The normal temperature infrared emissivities of the coating in its original state (before assessment), after thermal assessment at 600 °C, after thermal assessment at 1000 °C, and after quartz lamp assessment in the range of 3 - 5 μm are 0.29, 0.20, 0.16, and 0.15 respectively.

[0042] Comparative Example 2

[0043] The difference between this comparative example and Example 1 is that the bonding phase is a PbO - B2O3 glass phase, and bisphenol A epoxy resin is not added; other components and preparation methods are the same as those in Example 1.

[0044] In the process of preparing the coating in this comparative example, during step (5), it is cured at 70 °C for 2 h. The high-temperature infrared stealth coating has poor bonding with the resin-based thermal protection composite material. After gluing, the coating shows peeling, which is grade 3, and the adhesion is unqualified. The normal temperature infrared emissivities of the coating prepared in this comparative example in its original state (before assessment), after thermal assessment at 600 °C, after thermal assessment at 1000 °C, and after quartz lamp assessment in the range of 3 - 5 μm are 0.38, 0.23, 0.25, and 0.24 respectively.

[0045] Comparative Example 3

[0046] The difference between this comparative example and Example 1 is that the bonding phase is composed of 85% by mass of PbO - B2O3 glass phase and 18% by mass of bisphenol A epoxy resin; other component parameters and preparation methods are the same as those in Example 1.

[0047] In the process of preparing the coating in this comparative example, during step (5), it is cured at 70 °C for 2 h. The high-temperature infrared stealth coating has good bonding with the resin-based thermal protection composite material. After gluing, the coating has no peeling, which is grade 0, and the adhesion is qualified. The normal temperature infrared emissivities of the coating in its original state (before assessment), after thermal assessment at 600 °C, after thermal assessment at 1000 °C, and after quartz lamp assessment in the range of 3 - 5 μm are 0.24, 0.30, 0.39, and 0.37 respectively. After the assessment at 600 °C and 1000 °C, a small part of the coating falls off.

[0048] Example 2

[0049] A resin-based thermal protection composite material with a low-temperature-cured high-temperature infrared stealth coating on its surface, which consists of a resin-based thermal protection composite material and a high-temperature infrared stealth coating from the inside out. The resin-based thermal protection composite material uses glass fiber as the reinforcement and benzoxazine resin as the resin matrix. The weaving form of the reinforcement is a stitched fabric. The density of the resin-based thermal protection composite material is 1.50 g / cm 3。The high-temperature infrared stealth coating is composed of low-emissivity fillers and a binder phase. The mass fraction of the low-emissivity fillers in the high-temperature infrared stealth coating is 85%, which consists of a mixed filler of 45% by mass of nano silver powder and 55% by mass of flaky aluminum powder. The particle size of the nano silver is 60 nm, and the particle size of the flaky aluminum powder is 40 μm. The binder phase consists of 92% by mass of PbO-B2O3 glass phase and 8% by mass of bisphenol A epoxy resin. In the PbO-B2O3 glass phase, the mass fraction of PbO is 28% and the mass fraction of B2O3 is 72%. The glass softening point temperature is 350 °C, and the thickness of the high-temperature infrared stealth coating is 80 μm.

[0050] This embodiment also provides a preparation method of a resin-based heat-resistant composite material with a high-temperature infrared stealth coating on its surface, including the following steps:

[0051] (1) Clean the mold, apply a mold release agent on the surface of the mold, and complete the mold treatment;

[0052] (2) Assemble the resin-based composite fabric with the mold and conduct an airtightness inspection;

[0053] (3) Inject liquid benzoxazine resin with a viscosity of 50 mPa·s into the closed mold cavity under a pressure of 0.6 MPa to complete the infiltration of the resin-based composite fabric, heat and cure at 200 °C for 5 h, and then remove the mold to complete the preparation of the resin-based heat-resistant composite material;

[0054] (4) Conduct a grinding and roughening treatment on the surface of the resin-based heat-resistant composite material to be coated;

[0055] (5) Apply the high-temperature infrared stealth coating on the surface of the resin-based heat-resistant composite material by brush coating process, cure at 90 °C for 2 h, and complete the preparation of the high-temperature infrared stealth coating after polishing treatment.

[0056] Among them, in step (5), the high-temperature infrared stealth coating is prepared by the following method: Pass the glass powder after melting and ball milling through a 200 - 400 mesh sieve, then mix the glass powder, nano silver powder, and flaky aluminum powder evenly, and finally mix and grind them with bisphenol A epoxy resin and an organic carrier to obtain the high-temperature infrared stealth coating. The organic carrier in the high-temperature infrared stealth coating mainly consists of 75% by mass of butyl carbitol, 10% by mass of tributyl citrate, 5% by mass of ethyl cellulose, 5% by mass of Span-85, and 5% by mass of 1,4-butyrolactone. The mass fraction of the organic carrier in the high-temperature infrared stealth coating is 20%.

[0057] The high-temperature infrared stealth coating prepared in this example has good bonding with the surface of the resin-based heat-resistant composite material. After gluing, the coating has no peeling, which is grade 0, and the adhesion is qualified. The resin-based heat-resistant composite material with a high-temperature infrared stealth coating on its surface has passed the thermal tests at 600°C for 10 minutes and 1000°C for 10 minutes, and the quartz lamp thermal test (the hottest heat flux is 150 kW / m 2 , and the test time is 600 s). After the tests, the high-temperature infrared stealth coating is intact, without cracking, peeling and other phenomena. The measured normal-temperature infrared emissivities of the coating in its original state (before the test), after the 600°C thermal test, after the 1000°C thermal test, and after the quartz lamp test in the range of 3 - 5 μm are 0.25, 0.13, 0.15, and 0.15 respectively. The infrared emissivity of the high-temperature infrared stealth coating decreases significantly after the thermal test, indicating that the high-temperature infrared stealth coating prepared on the surface of the resin-based heat-resistant composite material exhibits the characteristics of low emissivity in a wide temperature range, excellent heat resistance, and strong high-temperature bonding with the substrate.

[0058] Example 3

[0059] A resin-based heat-resistant composite material with a low-temperature curing high-temperature infrared stealth coating on its surface consists of a resin-based heat-resistant composite material and a high-temperature infrared stealth coating from the inside to the outside. The resin-based heat-resistant composite material uses high-silica fiber as the reinforcement and phenolic resin as the resin matrix. The weaving form of the reinforcement is a needle-punched fabric, and the density of the resin-based heat-resistant composite material is 0.63 g / cm 3 . The high-temperature infrared stealth coating consists of a low-emissivity filler and a binder phase. The mass fraction of the low-emissivity filler in the high-temperature infrared stealth coating is 95%, which is composed of a mixed filler of 80% by mass of nano silver-palladium powder and 20% by mass of flaky aluminum powder. The mass fraction of nano silver powder in the nano silver-palladium powder is 85%, and the mass fraction of nano palladium powder is 15%. The particle size of the nano silver powder is 70 nm, the particle size of the nano palladium powder is 50 nm, and the particle size of the flaky aluminum powder is 35 μm. The binder phase consists of 95% by mass of PbO - B2O3 glass phase and 5% by mass of acrylic resin. The mass fraction of PbO in the PbO - B2O3 glass phase is 25%, and the mass fraction of B2O3 is 75%. The glass softening point temperature is 350°C, and the thickness of the high-temperature infrared stealth coating is 150 μm.

[0060] This example also provides a preparation method for the resin-based heat-resistant composite material with a high-temperature infrared stealth coating on its surface, including the following steps:

[0061] (1) Clean the mold and apply a mold release agent on the surface of the mold to complete the mold treatment;

[0062] (2) Assemble the resin-based composite fabric with the mold and conduct an airtightness inspection;

[0063] (3) Inject liquid phenolic resin with a viscosity of 40 mPa·s into the closed mold cavity under a pressure of 0.4 MPa to complete the infiltration of the resin matrix composite fabric, heat and cure it at 90 °C for 32 h, and then remove the mold to complete the preparation of the resin matrix heat-resistant composite material;

[0064] (4) Grind and roughen the surface of the resin matrix heat-resistant composite material to be coated;

[0065] (5) Coat the surface of the resin matrix heat-resistant composite material with a high-temperature infrared stealth coating by brush coating process, cure it at 100 °C for 2 h, and complete the preparation of the high-temperature infrared stealth coating after polishing.

[0066] Among them, in step (5), the high-temperature infrared stealth coating is prepared by the following method: Pass the glass powder after melting and ball milling through a 200-400 mesh sieve, then mix the glass powder, nano silver-palladium powder, and flaky aluminum powder evenly, and finally mix and grind them with acrylic resin and organic carrier to obtain the high-temperature infrared stealth coating. The organic carrier in the high-temperature infrared stealth coating is mainly composed of 73% butyl carbitol, 12% tributyl citrate, 5% ethyl cellulose, 4% Span-85, and 6% 1,4-butyrolactone by mass fraction, and the mass fraction of the organic carrier in the high-temperature infrared stealth coating is 20%.

[0067] The high-temperature infrared stealth coating prepared in this example has good adhesion to the surface of the resin matrix heat-resistant composite material. After sticking, the coating has no peeling and is rated as 0 level, and the adhesion is qualified. The resin matrix heat-resistant composite material with a high-temperature infrared stealth coating on the surface has passed the thermal tests at 600 °C for 10 min and 1000 °C for 10 min, and the quartz lamp thermal test (the hottest heat flux is 150 kW / m 2 , and the test time is 600 s). After the test, the high-temperature infrared stealth coating is intact without cracking, peeling and other phenomena. The measured normal temperature infrared emissivities of the coating in the original state (before the test), after the 600 °C thermal test, after the 1000 °C thermal test, and after the quartz lamp test at 3-5 μm are 0.21, 0.10, 0.12, and 0.12 respectively. The infrared emissivity of the high-temperature infrared stealth coating decreases significantly after the thermal test, indicating that the high-temperature infrared stealth coating prepared on the surface of the resin matrix heat-resistant composite material exhibits the characteristics of wide-temperature range and low emissivity, excellent heat resistance, and strong high-temperature bonding with the substrate.

[0068] The foregoing description of the specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A resin-based heat-resistant composite material with a low-temperature curing high-temperature infrared stealth coating on its surface, characterized in that: The invention comprises, from the inside to the outside, a resin-based heat-proof composite material and a high-temperature infrared stealth coating, wherein the high-temperature infrared stealth coating is composed of a low-emissivity filler and a bonding phase, wherein the low-emissivity filler is a mixed filler composed of nano silver powder or nano silver palladium powder and flaky aluminum powder, and the bonding phase is composed of a glass phase and an organic resin; the mass fraction of the low-emissivity filler in the coating is 80% to 95%, the mass fraction of the nano silver or nano silver palladium powder in the mixed filler is 10% to 90%, and the mass fraction of the flaky aluminum powder is 10% to 90%; the mass fraction of nano palladium in the nano silver palladium powder is 5% to 30%, and the mass fraction of nano silver is 70% to 95%; the particle size of the nano silver and nano palladium is 30nm to 150nm, and the particle size of the flaky aluminum powder is 5μm to 40μm; the mass content of the organic resin in the bonding phase is 5% to 10%, and the mass content of the glass phase is 90% to 95%, and the organic resin is one of epoxy resin, acrylic resin, epoxy-modified silicone resin, and fluororesin.

2. The resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating according to claim 1, characterized in that: The main component of the glass phase is PbO-B2O3, wherein the mass fraction of PbO is 1% to 30%, the mass fraction of B2O3 is 20% to 80%, and the softening point temperature is 350°C to 400°C.

3. The resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating according to claim 1, characterized in that: The resin-based heat-resistant composite material reinforcement is one of carbon fiber, glass fiber, high-silica fiber, aramid fiber, and quartz fiber; the resin matrix is ​​one of epoxy resin, phenolic resin, benzoxazine resin, aromatic acetylene resin, and silicon aromatic acetylene resin; the braiding form of the reinforcement is one of three-dimensional five-directional fabric, 2.5D fabric, stitched fabric, and needle-punched fabric; the density of the resin-based heat-resistant composite material is 0.5g / cm 3 ~1.5g / cm 3 .

4. The resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating according to claim 1, characterized in that: The high-temperature infrared stealth coating has a thickness of 10 μm to 200 μm.

5. A method for preparing a resin-based heat-resistant composite material with a surface coated with a low-temperature curing high-temperature infrared stealth coating as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Preparation of resin-based heat-resistant composite materials; (2) Grinding and roughening the coating surface of the resin-based heat-resistant composite material to be coated; (3) The high-temperature infrared stealth coating is applied to the surface of the resin-based heat-resistant composite material by brushing or room-temperature spraying, and then subjected to low-temperature curing and polishing. The low-temperature curing process parameters are: temperature of 70°C to 100°C and time of 1h to 2h to obtain a high-temperature infrared stealth coating.

6. The preparation method according to claim 5, characterized in that: The step (1) comprises cleaning the mold, applying a mold release agent on the mold surface, and completing mold processing; assembling the resin-based composite material fabric with the mold and performing an air tightness inspection; injecting liquid resin into the closed mold cavity under pressure to complete the infiltration of the resin-based composite material fabric, and obtaining the resin-based heat-resistant composite material through heating, curing, and demolding.

7. The preparation method according to claim 6, characterized in that: The infiltration pressure is 0.2MPa~1.2MPa; the viscosity of the liquid resin is 20mPa‧s~600mPa‧s; the heating curing temperature is 50℃~280℃, and the curing time is 2h~40h.

8. The preparation method according to claim 5, characterized in that: The high-temperature infrared stealth coating is mainly composed of a low-emissivity filler, a binder and an organic carrier; the binder is composed of glass powder and an organic resin; the high-temperature infrared stealth coating is prepared by the following method: the glass powder after melting, water cooling and ball milling is passed through a 200-400 mesh sieve, and then the glass powder and the low-emissivity filler are mixed evenly with a planetary gravity mixer, and then mixed evenly with the organic resin and the organic carrier, and then ground with a three-roll grinder to obtain the high-temperature infrared stealth coating.

9. The preparation method according to claim 8, characterized in that: The organic carrier is mainly composed of 70% to 80% by mass of butyl carbitol, 8% to 12% by mass of tributyl citrate, 2% to 5% by mass of ethyl cellulose, 2% to 5% by mass of Span-85 and 3% to 6% by mass of 1,4-butyrolactone. The mass fraction of the organic carrier in the high-temperature infrared stealth coating is 5% to 25%.

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