A high-efficiency modified absorber, a preparation method thereof, and a coating containing the modified absorber

Abstract

The present invention provides a high-efficiency modified absorber and its preparation method and a coating containing the modified absorber, the absorber including the following raw material components by mass: alloy powder (5-35): coating material (10-20): auxiliary agent (0.3-2); wherein the alloy powder is iron powder 20: nickel powder 1.8: cobalt 0.5 in parts by mass, smelted after vacuuming in a vacuum arc furnace, and then rapidly quenched by vacuum melt; the coating material is one of silicon carbide, iron oxide, graphene and conductive carbon black; the auxiliary agent is at least one of a silane coupling agent and a dispersant. The absorber of the present invention can be well dispersed in the coating with a dispersant of 0.05-0.3 parts by mass, has good radar absorption effect at the same thickness, and has a certain infrared stealth function. The preparation method is simple in process, cheap in price, suitable for mass production, and can be applied to military protection, etc.

Description

Technical Field

[0001] The present invention generally relates to the technical field of stealth materials and camouflage materials, and in particular to a high-efficiency modified absorber and a preparation method thereof, and a coating containing the modified absorber. Background Art

[0002] In the modern information battlefield, command, control, communication, computer, destruction, surveillance, reconnaissance (C 4 The integrated integration of technologies such as KISR, the rapid development and extensive application of various modern reconnaissance technologies and precision-guided weapons have formed all-weather and all-day reconnaissance capabilities based on satellites, early warning aircraft, drones, and high-altitude and high-speed reconnaissance aircraft, as well as a variety of strike methods such as long-range precision-guided missiles and smart bombs. Ground targets are facing increasingly severe battlefield threats.

[0003] Stealth coatings are the material foundation of camouflage and a crucial vehicle for achieving the desired stealth effect. They offer numerous advantages: First, they are versatile. They can be used directly for camouflage coatings on both stationary and mobile targets. They also serve as a foundational camouflage material, serving as a decorative coating on other camouflage equipment, such as camouflage nets, enhancing their performance. Second, they offer internal camouflage, a fundamental development in camouflage equipment. Informationized warfare demands full-scale mobility, with troops primarily engaged in mobile operations, both offensively and defensively. This demands that camouflage equipment adapted to the characteristics of modern warfare remain relevant and maintain mobility. Stealth coatings, as an internal camouflage technology, are well-suited for protecting weapons and equipment during mobile operations, making them a crucial component of ground weapon and equipment protection. Third, they are easy to use and cost-effective, making them suitable for widespread deployment and a widely adopted stealth method by military forces both domestically and internationally.

[0004] Of course, with the development of reconnaissance, surveillance, guidance and acquisition technologies, especially the development of multi-band, multi-system sensor fusion detection technology, stealth coatings must also develop and advance to adapt to these changes and meet these challenges. This requires the development of corresponding materials, coatings, processes, etc.

[0005] In the radar band, battlefield threats facing ground targets primarily come from reconnaissance and surveillance by various short-range search, tracking, and fire control radars, and radar-guided strikes by precision-guided weapons. The former primarily operate in the X- and Ku-bands, while the latter primarily operate in the Ku-, Ka-, and W-bands. To effectively counter reconnaissance and guided strikes, ground equipment requires multi-band stealth capabilities encompassing the C-, X-, Ku-, and Ka-bands. Traditional radar absorbers have a relatively narrow absorption band and are unable to achieve multi-band stealth capabilities across the C-, X-, Ku-, and Ka-bands. Summary of the Invention

[0006] The present invention aims to provide a highly efficient modified absorber, a preparation method thereof, and a coating containing the modified absorber. The highly efficient modified absorber is formed by coating the surface of alloy powder having magnetic loss properties with a conductive material. While maintaining the absorber's magnetic loss properties, it also maintains electrical loss properties, achieving electromagnetic loss compatibility and realizing multi-band stealth capabilities in the C, X, Ku, and Ka bands. Furthermore, a preparation method is provided, and the highly efficient modified absorber can be used in research fields requiring multi-band radar absorption, such as multi-spectrum camouflage coatings.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a high-efficiency modified absorber, comprising the following raw material components: alloy powder, coating material, and additives. The raw materials of the alloy powder include iron powder, nickel powder, and cobalt powder. The iron powder, nickel powder, and cobalt powder are smelted in a vacuum arc furnace after vacuuming in a ratio of 20:1.8:0.5 by mass.

[0008] Furthermore, the alloy powder of the present invention is in the form of flakes with a thickness of 1-5 μm and a particle size of 20-60 μm.

[0009] The preparation method of the alloy powder comprises the following steps:

[0010] Step 1: Place the raw materials weighed according to the formula in a vacuum arc furnace to reach 1.0×10 -4 -1.0×10 -5 Pa-level vacuum melting, melting temperature is 1580-1650℃, and the molten sample is stirred to make it evenly mixed. After melting, it is naturally cooled to obtain alloy balls;

[0011] Step 2: Grind the alloy ball with a grinding wheel to remove the oxide layer on the surface of the ball;

[0012] Step 3: After removing the oxide layer, the sample is mechanically crushed and placed in a quartz tube. The quartz tube is vacuumed to a pressure of 1.0×10 -4 -1.0×10 -5 Vacuum degree in Pa level;

[0013] Step 4: Then, high-purity argon gas is flushed into the quartz tube, and the sample is melted by induction melting. After it is completely melted, the atmospheric pressure difference inside and outside the quartz tube is used to spray the molten alloy ball onto a rapidly rotating copper roller at a speed of 600-1500r / min to obtain flaky alloy powder;

[0014] Furthermore, the coating material is one of silicon carbide, iron oxide, graphene and conductive carbon black.

[0015] Furthermore, the high-efficiency modified absorber comprises alloy powder, coating material, and additive in a mass ratio of (5-35): (10-20): (0.3-2).

[0016] Furthermore, the auxiliary agent is at least one of a silane coupling agent and a dispersant.

[0017] The present invention also provides a method for preparing the above-mentioned high-efficiency modified absorber, comprising the following steps:

[0018] S1: Weigh each raw material component, add a predetermined amount of solvent, and ball mill for 4-12 hours to obtain a high-efficiency modified absorber slurry;

[0019] S2: removing the solvent from the obtained high-efficiency modified absorber slurry by suction filtration;

[0020] S3: using anhydrous ethanol to disperse and clean the filtered high-efficiency modified absorber;

[0021] S4: Repeat steps S2-S3 2-3 times to obtain a high-efficiency modified absorber slurry containing ethanol;

[0022] S5: vacuum drying the high-efficiency modified absorber slurry obtained in S4 at 60-80° C. until the ethanol is completely volatilized to obtain the high-efficiency modified absorber finished product.

[0023] Preferably, in step S1, the solvent is one of xylene, acetone and DMF, and the amount of the solvent is in a ratio of (10-28) to (5-35) by mass of the alloy powder.

[0024] Preferably, in step S1, ball milling refers to adding zirconia balls with a diameter of 2.0-2.5 mm to the raw material components and ball milling at a speed of 500-600 r / min in a planetary ball mill.

[0025] Preferably, in step S2 and step S3, anhydrous ethanol is used as a cleaning agent for both the filtration and the dispersion cleaning, wherein the dispersion cleaning refers to adding the filtered high-efficiency modified absorber to ethanol and then dispersing it at a speed of 200-400 r / min for 3-8 minutes.

[0026] The present invention also provides a radar absorbing coating, the raw material components of which include the high-efficiency modified absorber of the present invention, and the coating components include, by mass, 6-10 parts of modified epoxy resin: 50-80 parts of high-efficiency modified absorber: 10-20 parts of diluent: and 0.05-0.3 parts of dispersant.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The high-efficiency modified radar absorber provided by the present invention includes alloy powder and a coating material that coats the alloy powder. The alloy powder includes iron powder, nickel powder, and cobalt powder, which are smelted in a vacuum arc furnace after evacuation. Compared with traditional radar absorbers, when the addition amount and spray thickness are the same, the radar absorber of the present invention has better radar absorbing effect and wider absorption frequency band, and can achieve multi-band stealth capability in the C, X, Ku, and Ka bands.

[0029] 2. The vacuum quenching technique employed in this invention to produce thin (flake) alloy powders allows for the solidification of metals or alloys at extremely high undercooling rates, resulting in a non-equilibrium microstructure with an ultrafine structure. Furthermore, because the speed of the cooling copper roller is adjustable, the cooling rate can be strictly controlled, thereby achieving control over the grain size of the metal or alloy. When the liquid alloy is directly sprayed onto a high-speed rotating copper roller, the solidification process is non-equilibrium, and the size of the alloy grains is closely related to the undercooling. When the quenching rate is less than 600 r / min, the temperature gradient is small, resulting in larger grains in the sample. When the copper roller speed exceeds 1500 r / min, the undercooling increases, forming more crystal nuclei. At this point, the grains have little time to grow, and the alloy is fully solidified, resulting in very small grains in the quenched zone, leading to the appearance of an amorphous phase. Another advantage of vacuum melt quenching is that since cooling occurs in a vacuum, nearly all metals and alloys can be quenched, and amorphous phases can be formed in a variety of metals and alloys. Therefore, vacuum quenching can not only control the crystalline and amorphous states of metals and alloys, but also the grain size of the crystalline metals or alloys, particularly producing nanocrystalline grains. By adjusting the copper wheel speed between 40m / s and 60m / s, the present invention produces alloy powder with an amorphous-to-crystalline ratio of 1:1 (1-2.5). The alloy powder has a particle size of 1-30 microns and a thickness of 20-40μm. This combination of amorphous-to-crystalline and particle size achieves optimal radar absorption.

[0030] 3. The present invention prepares a high-efficiency modified absorber through the selection of coating process and coating material. Compared with traditional absorbers, the radar absorbing coating prepared has a wider absorption band, better radar absorption effect and infrared stealth function at the same thickness and the same absorber addition amount.

[0031] 4. The preparation method of the high-efficiency modified absorber provided by the present invention has simple process performance, is suitable for mass production, and is inexpensive. Coatings containing the high-efficiency modified absorber can also be well applied in engineering construction without requiring harsh construction conditions. They can be used in military protection, such as wide-band radar stealth and infrared stealth. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] These and / or other aspects and advantages of the present invention will become more apparent and more readily understood from the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0033] Figure 1 This is a scanning electron microscope image of the high-efficiency modified absorber obtained in the present invention;

[0034] Figure 2 2-18 GHz and 26.5-40 GHz radar reflectivity curves of radar absorbing coatings prepared from the alloy powder obtained in the present invention and three metal powders;

[0035] Figure 3 Radar reflectivity curves of the modified absorber at 2-18 GHz and 26.5-40 GHz in Example 2;

[0036] Figure 4 2-18 GHz and 26.5-40 GHz radar reflectivity curves of the high-efficiency modified absorber obtained in Example 3;

[0037] Figure 5 Radar reflectivity curves of the modified absorber obtained in Example 4 at 2-18 GHz and 26.5-40 GHz;

[0038] Figure 6 Schematic diagram of the vacuum quenching device used in the present invention; wherein, 1-induction coil; 2-cooling copper roller; 3-quartz tube; 4-molten alloy; 5-flaky powder. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of the present invention.

[0040] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] Unless otherwise specified, all drugs / reagents used were commercially available.

[0042] Example 1

[0043] Disclosed is an alloy powder. The alloy powder comprises iron powder, nickel powder and cobalt powder in a ratio of 20:1.8:0.5 by mass. The raw materials are smelted in a vacuum arc melting furnace after vacuuming.

[0044] The specific preparation method comprises the following steps:

[0045] S1: The raw materials weighed according to the formula are placed in a vacuum arc furnace to reach 1.0×10 -4 Melt the sample in a vacuum of Pa level at 1600℃ and stir the sample with a hand crank for 2 minutes to make the sample as evenly mixed as possible. After melting and cooling, a well-mixed alloy ball is formed.

[0046] S2: The alloy balls are polished with a grinding wheel to remove the oxide layer on the surface of the balls. The alloy balls obtained after smelting have coarse grains, which is not conducive to obtaining samples with excellent performance. Therefore, the alloy balls need to be processed using melt rapid quenching technology;

[0047] S3: The smelted sample is mechanically crushed and placed into the bottom quartz tube, and the quartz tube is vacuumed to 1.0×10 -4 Level of vacuum;

[0048] S4: High-purity argon gas is then injected into the quartz tube, and then the alloy balls are melted by induction melting at a temperature of 1600°C. After they are completely melted, the atmospheric pressure difference between the inside and outside of the quartz tube is used to spray the molten alloy balls onto a rapidly rotating copper roller at a speed of 1200 r / min. The rapidly rotating copper roller has an extremely fast cooling rate, which can produce a flake sample. The final alloy powder has a thickness of 1-5 μm and a particle size of 20-60 μm.

[0049] The specific process of steps S3-S4 involves the following devices: Figure 6 As shown, the induction coil 1 is used to melt the mechanically crushed sample inside the quartz tube 3 to form a molten alloy 4. The molten alloy 4 is ejected onto the rotating cooling copper roller 2 due to the pressure difference inside the quartz tube 3. Due to the temperature and rotation speed of the cooling copper roller 2, the molten alloy 4 forms flaky powder.

[0050] The formula of the radar absorbing coating using the alloy powder prepared in Example 1 as the absorbing agent and the three raw materials alone as the absorbing agents is shown in Table 1 below:

[0051] Table 1 Radar absorbing coating formula prepared from alloy powder and three raw materials (parts by mass)

[0052]

[0053] The prepared radar absorbing coating was prepared in a ratio of coating: curing agent = 10:1 to a viscosity of 18-22s (4-cup coating method). The obtained coating was sprayed on a 300mm×300mm aluminum plate in multiple times with a thickness of 1mm±0.1. The radar reflectivity curves of the coating in the C, X, Ku and Ka bands were tested as shown below. Figure 2 As shown, it can be seen that the radar absorbing performance of the alloy powder prepared in this embodiment is better than the radar absorbing performance of the radar absorbing coatings prepared from the three raw materials alone.

[0054] Example 2

[0055] A graphene-coated modified absorber and a radar absorbing coating containing the modified absorber

[0056] A graphene-coated absorber comprises raw materials comprising alloy powder, graphene, acetone, and a silane coupling agent in a ratio of 35:20:28:2 by mass; the alloy powder is the alloy powder obtained in Example 1, and the raw materials are ball-milled in a container containing zirconium oxide balls to obtain a graphene-coated modified absorber.

[0057] The specific preparation method comprises the following steps:

[0058] S1: Weigh the raw material components of the high-efficiency modified absorber according to the mass ratio, and ball-mill for 12 hours to obtain a graphene-modified absorber slurry;

[0059] S2: removing the solvent from the obtained graphene-modified absorber slurry by suction filtration;

[0060] S3: The filtered graphene absorber is dispersed and cleaned with anhydrous ethanol;

[0061] S4: Repeat steps S2-S3 2-3 times to obtain a graphene-modified absorber slurry containing ethanol;

[0062] S5: The graphene-modified absorber slurry obtained in S4 is vacuum-dried at 60-80° C. until the ethanol is completely volatilized, thereby obtaining the desired graphene-modified absorber product.

[0063] The specific formula of a radar absorbing coating containing a graphene-modified absorber is shown in Table 2:

[0064] Table 2 Radar absorbing coating formula based on graphene modified absorber

[0065]

[0066] The prepared radar absorbing coating was prepared in a ratio of coating: curing agent = 10:1 to a viscosity of 18-22s (4 cup coating method). The obtained coating was sprayed on a 300mmX300mm aluminum plate in multiple times with a thickness of 1mm±0.1. The radar reflectivity curves of the coating in the C, X, Ku and Ka bands were tested as shown below. Figure 3 The infrared emissivity of 3-5μm and 8-14μm is shown in Table 5.

[0067] Tests have shown that the radar absorption performance and infrared stealth performance obtained in this embodiment meet the requirements of relevant national military standards.

[0068] Example 3

[0069] A silicon carbide-coated modified absorber and a radar absorbing coating containing the modified absorber

[0070] A silicon carbide-coated wave absorber, comprising raw materials comprising alloy powder, silicon carbide, acetone, and a silane coupling agent in a ratio of 5:10:15:0.5 by mass; the alloy powder is the alloy powder obtained in Example 1, and the raw materials are ball-milled in a container containing zirconium oxide balls to obtain a silicon carbide-coated modified wave absorber.

[0071] The specific preparation method comprises the following steps:

[0072] S1: Weigh the raw material components of the high-efficiency modified absorber according to the mass ratio, and ball-mill for 4 hours to obtain a silicon carbide modified absorber slurry;

[0073] S2: removing the solvent from the obtained silicon carbide modified absorber slurry by suction filtration;

[0074] S3: using anhydrous ethanol to disperse and clean the filtered silicon carbide absorber;

[0075] S4: Repeat steps S2-S3 2-3 times to obtain an ethanol-containing silicon carbide modified absorber slurry;

[0076] S5: The silicon carbide modified absorber slurry obtained in S4 is vacuum dried at 60-80° C. until the ethanol is completely volatilized to obtain the desired silicon carbide modified absorber finished product.

[0077] A radar absorbing coating with a silicon carbide modified absorber, the specific formula is shown in Table 3:

[0078] Table 3 Multi-spectrum coating formulation based on silicon carbide modified absorber

[0079]

[0080] The prepared radar absorbing coating was prepared in a ratio of coating: curing agent = 12.5:1 to a viscosity of 18-22s (4 cup coating method). The obtained coating was sprayed on a 300mmX300mm aluminum plate in multiple times with a thickness of 1mm±0.1. The radar reflectivity curves of the coating in the C, X, Ku and Ka bands were tested as shown below. Figure 4 The infrared emissivity at 3-5 μm and 8-14 μm is shown in Table 5. The radar absorbing performance and infrared stealth performance obtained in this embodiment meet the requirements of relevant national military standards.

[0081] Example 4

[0082] A modified wave absorbing agent coated with iron oxide and a radar absorbing coating containing the modified wave absorbing agent

[0083] A modified iron oxide-coated absorber is obtained by ball milling the raw materials in a container containing zirconium oxide balls to obtain an iron oxide-coated modified absorber. The raw materials of the silicon carbide-coated absorber include alloy powder, iron oxide, acetone, and a dispersant in a mass ratio of 20:15:10:0.3. The alloy powder is the alloy powder obtained in Example 1.

[0084] The specific preparation method comprises the following steps:

[0085] S1: Weigh the raw material components of the high-efficiency modified absorber according to the mass ratio, and ball-mill for 8 hours to obtain an iron oxide modified absorber slurry;

[0086] S2: removing the solvent from the obtained iron oxide modified absorber slurry by suction filtration;

[0087] S3: using anhydrous ethanol to disperse and clean the filtered iron oxide absorber;

[0088] S4: Repeat steps S2-S3 2-3 times to obtain an iron oxide modified absorber slurry containing ethanol;

[0089] S5: The iron oxide modified absorber slurry obtained in S4 is vacuum dried at 60-80° C. until the ethanol is completely volatilized to obtain the desired iron oxide modified absorber product.

[0090] A radar absorbing coating with an iron oxide modified absorber, the specific formula is shown in Table 4:

[0091] Table 4 Radar absorbing coating formula based on iron oxide modified absorber

[0092]

[0093] The prepared radar absorbing coating was prepared in a ratio of coating: curing agent = 11:1 to a viscosity of 18-22s (4 cup coating method). The obtained coating was sprayed on a 300mmX300mm aluminum plate in multiple times with a thickness of 1mm±0.1. The radar reflectivity curves of the coating in the C, X, Ku and Ka bands were tested as shown below. Figure 5 The infrared emissivity at 3-5 μm and 8-14 μm is shown in Table 5: The radar absorbing performance and infrared stealth performance obtained in this embodiment meet the requirements of relevant national military standards.

[0094] The test data related to the embodiment are shown in Table 5:

[0095] Table 5 Test results of the coatings obtained in Examples 1-4 of the present invention

[0096]

[0097] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. Therefore, the scope of the present invention shall be determined by the scope of the claims.

Claims

1. A radar absorbing coating, characterized in that: The coating comprises 6-10 parts by mass of a modified epoxy resin, 50-80 parts by mass of a high-efficiency modified absorber, 10-20 parts by mass of a diluent, and 0.05-0.3 parts by mass of a dispersant. The coating can achieve multi-band stealth capabilities in the C, X, Ku, and Ka bands, and also possesses infrared stealth capabilities. The high-efficiency modified absorber comprises the following raw material components: Alloy powder, coating material, and additive, wherein the coating material is coated on the surface of the alloy powder; the mass ratio of the alloy powder, coating material, and additive is (5-35): (10-20): (0.3-2); The raw materials of the alloy powder include iron powder, nickel powder and cobalt powder, which are smelted in a vacuum arc furnace at a ratio of 20:1.8:0.5 by mass; The alloy powder is in the form of flakes with a thickness of 1-5 μm and a particle size of 20-60 μm. The preparation method of the alloy powder comprises the following steps: Step 1: Place the raw materials weighed according to the formula in a vacuum arc furnace to reach 1.0×10 -4 -1.0×10 - 5 Pa-level vacuum melting, melting temperature is 1580-1650℃, and the molten sample is stirred to make it evenly mixed. After melting, it is naturally cooled to obtain alloy balls; Step 2: Grind the alloy ball with a grinding wheel to remove the oxide layer on the surface of the ball; Step 3: After removing the oxide layer, the sample is mechanically crushed and placed in a quartz tube, and the quartz tube is vacuumed to a pressure of 1.0×10 -4 -1.0×10 -5 Vacuum degree in Pa level; Step 4: Then, high-purity argon gas is flushed into the quartz tube, and then the sample is melted by induction melting. After it is completely melted, the atmospheric pressure difference inside and outside the quartz tube is used to spray the molten alloy ball onto a rapidly rotating cooling copper roller at a speed of 800-1500r / min, so that a flake sample can be obtained, and finally the alloy powder is obtained; The coating material is one of silicon carbide, iron oxide, graphene and conductive carbon black; The preparation method of the high-efficiency modified absorber comprises the following steps: S1: Weigh each raw material component, add a predetermined amount of solvent, and ball mill for 4-12 hours to obtain a high-efficiency modified absorber slurry; S2: removing the solvent from the obtained high-efficiency modified absorber slurry by suction filtration; S3: using anhydrous ethanol to disperse and clean the filtered high-efficiency modified absorber; S4: Repeat steps S2-S3 2-3 times to obtain a high-efficiency modified absorber slurry containing ethanol; S5: vacuum drying the high-efficiency modified absorber slurry obtained in S4 at 60-80° C. until the ethanol is completely volatilized to obtain the high-efficiency modified absorber finished product.

2. The radar absorbing coating according to claim 1, characterized in that: The auxiliary agent is at least one of a silane coupling agent and a dispersant.

3. The radar absorbing coating according to claim 1, characterized in that: In the step S1, the solvent is one of xylene, acetone and DMF, and the amount of the solvent is in a ratio of (10-28) to (5-35) based on the mass of the alloy powder.

4. The radar absorbing coating according to claim 1, characterized in that: In step S1, ball milling refers to adding zirconia balls with a diameter of 2.0-2.5 mm to the raw material components and ball milling at a speed of 500-600 r / min in a planetary ball mill.

5. The radar absorbing coating according to claim 1, characterized in that: In step S2 and step S3, anhydrous ethanol is used as a cleaning agent for both the suction filtration and the dispersion cleaning, wherein the dispersion cleaning refers to adding the filtered high-efficiency modified absorber into ethanol and then dispersing it at a speed of 200-400 r / min for 3-8 minutes.

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