A kind of high absorption and high emission thermal control coating on aluminum alloy surface and preparation method thereof

Abstract

The present invention discloses a high-absorption and high-emission thermal control coating on the surface of an aluminum alloy and a preparation method thereof, and relates to the field of surface engineering technology. The method comprises: pre-treatment of the aluminum alloy; placing the pre-treated aluminum alloy as an anode in an oxidation tank, using a sulfuric acid solution as a reaction solution, and adopting a multi-stage reaction method to oxidize the pre-treated aluminum alloy; placing the aluminum alloy in a coloring tank, and coloring it with a black acid dye solution as a coloring liquid; coating the surface of the aluminum alloy with a surface modifier, and obtaining the high-absorption and high-emission thermal control coating on the surface of the aluminum alloy after solidification of the surface modifier. The present invention utilizes anodizing, coloring and sol-gel composite coating technology to prepare a high-absorption and high-emission thermal control coating with low vacuum volatile pollution and good bonding strength on the surface of the aluminum alloy, which solves the problems of vacuum volatiles causing optical component pollution and poor coating bonding strength in the thermal control coating on the surface of the current spacecraft aluminum alloy optical device.

Description

Technical Field

[0001] The present invention relates to the field of surface engineering technology, and in particular to a high-absorption and high-emission thermal control coating on an aluminum alloy surface and a preparation method thereof. Background Art

[0002] High absorption and high emission thermal control coatings have high absorption rates (generally > 0.80) for sunlight in the 0.3-2.5μm and 2.5-25μm bands, and also have high emissivity (generally > 0.80) in the 2.5-25μm range. This type of coating can significantly improve detection accuracy and resolution when applied to aerospace infrared imaging optical systems. In addition, high absorption and high emission coatings can also be used as stray light elimination materials for aerospace optical devices, playing a role in eliminating stray light in optical systems and effectively improving the sensitivity and reliability of optical detectors. It is precisely because of its unique optical and thermal radiation properties that it has been widely used in spacecraft such as remote sensing and high-resolution detection satellites.

[0003] At present, the high-absorption and high-emission thermal control coatings for spacecraft mainly use organic adhesives and black pigments. For example, American spacecraft mostly use Z306, Russian spacecraft mostly use AK-512, AK-243, KO-818, etc., and my country's spacecraft use independently developed SR107-E51, E51-M, HA95, ERB-2B, etc. Such high-absorption and high-emission thermal control coatings mainly use silicone resin, acrylic resin, epoxy resin, etc. as adhesives. After long-term service under high vacuum conditions, as the low molecular weight substances in the coating are gradually released, the surface of the optical element is easily contaminated, and the organic coating also has problems such as easy aging, insufficient bonding strength, and short service life. With the continuous improvement of the detection accuracy, service life and reliability requirements of spacecraft at home and abroad, there is an urgent need for inorganic and organic-inorganic hybrid high-absorption and high-emission thermal control coatings with low molecular weight release characteristics.

[0004] Aluminum alloy is a commonly used structural material for spacecraft optical devices. The development of high-absorption and high-emission thermal control coatings with low-molecular-weight release characteristics suitable for the surface of aluminum alloy is of great value for improving the detection capability, service life and reliability of spacecraft. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to provide a high-absorption and high-emission thermal control coating with low-molecular-weight release characteristics suitable for the surface of aluminum alloy.

[0006] In order to solve the above problems, in a first aspect, the present invention provides a method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface, comprising:

[0007] S1, placing the pre-treated aluminum alloy as an anode in an oxidation tank, using a sulfuric acid solution as a reaction solution, and performing an oxidation reaction on the pre-treated aluminum alloy in a multi-stage reaction manner, wherein the multi-stage reaction includes a first-stage reaction, a second-stage reaction, and a third-stage reaction; the voltage of the first-stage reaction is 10-15V, and the reaction time is 5-10min; the voltage of the second-stage reaction is 15-20V, and the reaction time is 10-40min; the voltage of the third-stage reaction is 20-30V, and the reaction time is 0.5-5min;

[0008] S2, placing the aluminum alloy treated in step S1 in a coloring tank, and coloring the aluminum alloy using a black acid dye solution with a pH value of 4-6.5 as a coloring liquid, wherein the coloring time is 10-40 minutes;

[0009] S3, coating the surface modifier on the surface of the aluminum alloy treated in step S2, and obtaining a high-absorption and high-emission thermal control coating on the surface of the aluminum alloy after the surface modifier is solidified, wherein the surface modifier includes silica sol and metal salt, the particle size range of the silica sol is 50-100nm, the concentration of the silica sol is 1-5wt%, and the concentration of the metal salt is 0.2-5wt%.

[0010] Step S1 adopts a multi-stage reaction, which can avoid the problem of excessive stress and the resulting cracking caused by a complete one-time reaction.

[0011] The further technical solution is that in step S1, the concentration of the sulfuric acid solution is 140-200 g / L; the temperature of the sulfuric acid solution is 20-50°C

[0012] A further technical solution is that in step S2, the black acid dye solution includes a colorant, and the concentration of the colorant is 5-15 g / L; the temperature of the black acid dye solution is 20-50°C.

[0013] A further technical solution is that the colorant includes at least one of acid black ATT and Everlight K032.

[0014] A further technical solution is that in step S2, the metal salt includes at least one of Co(CH3COO)2, Na3VO4 and Fe2(SO4)3.

[0015] Its further technical solution is that step S3 comprises:

[0016] The surface modifier is coated on the surface of the aluminum alloy treated in step S2 by spraying, and the surface modifier is cured by heat preservation at 40-100° C. for 1-15 hours, wherein the number of spraying is 4-8 times.

[0017] A further technical solution is that after the pre-treated aluminum alloy is subjected to oxidation reaction in a multi-stage reaction manner, step S1 further comprises:

[0018] The aluminum alloy after the oxidation reaction is taken out from the oxidation tank, cleaned with pure water, and dried. Specifically, the drying can be done by natural drying or compressed air drying.

[0019] A further technical solution is that after the coloring treatment is performed using a black acid dye solution with a pH value of 4-6.5 as the coloring liquid, step S2 further includes:

[0020] The aluminum alloy after dyeing is taken out from the coloring tank, cleaned with pure water, and dried. Specifically, the drying can be done by natural drying or compressed air drying.

[0021] A further technical solution is that, before step S1, the method further includes:

[0022] Use an organic solvent to wipe the surface of the aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it;

[0023] The aluminum alloy is immersed in a 60-90° C. sodium hydroxide solution for 10-70 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy is completely removed, the aluminum alloy is taken out and cleaned with pure water and dried to obtain the pre-treated aluminum alloy; wherein the concentration of the sodium hydroxide solution used is 10-60 g / L, and the concentration of the nitric acid used is 200-400 g / L.

[0024] Specifically, the drying can be carried out by natural air drying or compressed air drying.

[0025] A further technical solution is that the grades of aluminum alloy include 2024, 6063 and 7055.

[0026] In a second aspect, the present invention provides a high-absorption and high-emissive thermal control coating on the surface of an aluminum alloy, wherein the high-absorption and high-emissive thermal control coating on the surface of an aluminum alloy is prepared by the method described in the first aspect.

[0027] Compared with the prior art, the technical effects achieved by the present invention include:

[0028] (1) The present invention utilizes anodizing, coloring and sol-gel composite coating technology to prepare a high-absorption and high-emission thermal control coating with low vacuum volatile pollution and good bonding strength on the surface of aluminum alloy, which solves the problems of vacuum volatiles causing optical component pollution and unsatisfactory coating bonding strength in the organic high-absorption and high-emission thermal control coatings widely used on the surface of aluminum alloy optical devices of current spacecraft, and thus makes it difficult to meet the requirements of long-life and high-reliability service of aerospace products. This technology has important application value in the manufacture of high-performance detection payloads such as spacecraft optical devices.

[0029] (2) The high-absorption and high-emission thermal control coating on the surface of the aluminum alloy prepared by the present invention has a coating thickness of 35-50 μm, a coating solar absorptivity of 0.82-0.95, an infrared emissivity of 0.85-0.95, a cross-hatch bonding strength of level 1, a vacuum condensable volatile matter requirement of ≤0.5%, and no damage or shedding after 100 times of thermal cycling at -196°C to +100°C. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments are described clearly and completely below. Obviously, the embodiments described below are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0032] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0033] Example 1

[0034] The present embodiment provides a method for preparing a high-absorption and high-emission thermal control coating on the surface of an aluminum alloy, which is specifically prepared according to the following steps:

[0035] (1) Pretreatment

[0036] Use gasoline to wipe the surface of the aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it. The grade of the aluminum alloy is 2024;

[0037] The aluminum alloy was immersed in a 60°C sodium hydroxide solution for 30 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy was completely removed, the aluminum alloy was taken out and cleaned with pure water and dried; wherein the concentration of the sodium hydroxide solution used was 30g / L, and the concentration of the nitric acid used was 250g / L.

[0038] (2) Sulfuric acid anodizing

[0039] The aluminum alloy treated in step (1) is placed in an oxidation tank as an anode, and a sulfuric acid solution is used as a reaction solution. The aluminum alloy treated in step (1) is oxidized by a multi-stage reaction, wherein the multi-stage reaction includes a first-stage reaction, a second-stage reaction, and a third-stage reaction; the voltage of the first-stage reaction is 10V, and the reaction time is 10min; the voltage of the second-stage reaction is 17V, and the reaction time is 15min; the voltage of the third-stage reaction is 20V, and the reaction time is 2min; the aluminum alloy after the oxidation reaction is taken out of the oxidation tank, cleaned with pure water, and dried. The concentration of the sulfuric acid solution is 140g / L; the temperature of the sulfuric acid solution is 30°C.

[0040] (3) Coloring

[0041] S2, placing the aluminum alloy treated in step (2) in a coloring tank, and coloring the aluminum alloy with a black acid dye solution having a pH value of 5 as a coloring liquid, wherein the coloring time is 20 minutes; taking the aluminum alloy out of the coloring tank after the coloring is completed, cleaning it with pure water, and drying it. The colorant of the black acid dye solution is acid black ATT, and the solvent is a mixture of ethanol, methanol and pure water, wherein the volume ratio of ethanol, methanol and pure water is 1:1:1, and the concentration of the colorant is 5g / L; the temperature of the black acid dye solution is 30°C.

[0042] (4) Surface coating

[0043] The surface modifier is coated on the surface of the aluminum alloy treated in step (3) by spraying, and the surface modifier is solidified by keeping the temperature at 100°C for 8 hours, wherein the spraying is repeated 5 times, and the surface modifier includes silica sol and metal salt Co(CH3COO)2, the particle size of the silica sol is 50nm, the concentration of the silica sol is 1wt%, and the concentration of the metal salt is 0.2wt%; the solvent of the surface modifier is a mixture of ethanol, methanol and pure water, wherein the volume ratio of ethanol, methanol and pure water is 1:1:1.

[0044] The high-absorption and high-emission thermal control coating on the aluminum alloy surface prepared in this embodiment has a coating thickness of 40 μm, a solar absorptivity of 0.92, an infrared emissivity of 0.87, a cross-hatch bonding strength of level 1, and a vacuum condensable volatile content of 0.2%. It can withstand 100 thermal cycles from -196°C to +100°C without being damaged or falling off.

[0045] Example 2

[0046] The present embodiment provides a method for preparing a high-absorption and high-emission thermal control coating on the surface of an aluminum alloy, which is specifically prepared according to the following steps:

[0047] (1) Pretreatment

[0048] Use ethanol to wipe the surface of the aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it. The grade of the aluminum alloy is 6063;

[0049] The aluminum alloy was immersed in a 60°C sodium hydroxide solution for 30 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy was completely removed, the aluminum alloy was taken out and cleaned with pure water and dried; wherein the concentration of the sodium hydroxide solution used was 30g / L, and the concentration of the nitric acid used was 400g / L.

[0050] (2) Sulfuric acid anodizing

[0051] The aluminum alloy treated in step (1) is placed in an oxidation tank as an anode, and a sulfuric acid solution is used as a reaction solution. The aluminum alloy treated in step (1) is oxidized by a multi-stage reaction, wherein the multi-stage reaction includes a first-stage reaction, a second-stage reaction, and a third-stage reaction; the voltage of the first-stage reaction is 10V, and the reaction time is 5min; the voltage of the second-stage reaction is 15V, and the reaction time is 20min; the voltage of the third-stage reaction is 20V, and the reaction time is 3min; the aluminum alloy after the oxidation reaction is taken out of the oxidation tank, cleaned with pure water, and dried. The concentration of the sulfuric acid solution is 200g / L; the temperature of the sulfuric acid solution is 50°C.

[0052] (3) Coloring

[0053] S2, placing the aluminum alloy treated in step (2) in a coloring tank, and coloring the aluminum alloy with a black acid dye solution having a pH value of 6.5 as a coloring liquid, wherein the coloring time is 40 minutes; taking the aluminum alloy out of the coloring tank after the coloring is completed, cleaning it with pure water, and drying it. The colorant of the black acid dye solution is Yongguang K032, and the solvent is a mixture of ethanol, methanol and pure water, wherein the volume ratio of ethanol, methanol to pure water is 1:1:1. The concentration of the colorant is 15g / L; and the temperature of the black acid dye solution is 40°C.

[0054] (4) Surface coating

[0055] The surface modifier is coated on the surface of the aluminum alloy treated in step (3) by spraying, and the surface modifier is cured by keeping the temperature at 90°C for 15 hours, wherein the spraying is performed 6 times, the surface modifier includes silica sol and metal salt Na3VO4, the particle size of the silica sol is 80nm, the concentration of the silica sol is 3wt%, and the concentration of the metal salt is 2wt%; the solvent of the surface modifier is a mixture of ethanol, methanol and pure water, wherein the volume ratio of ethanol, methanol and pure water is 1:1:1.

[0056] The high-absorption and high-emission thermal control coating on the aluminum alloy surface prepared in this embodiment has a coating thickness of 45 μm, a solar absorptivity of 0.93, an infrared emissivity of 0.88, a cross-hatch bonding strength of level 1, a vacuum condensable volatile requirement of 0.28%, and no damage or falling off occurs after 100 times of thermal cycling at -196°C to +100°C.

[0057] Example 3

[0058] The present embodiment provides a method for preparing a high-absorption and high-emission thermal control coating on the surface of an aluminum alloy, which is specifically prepared according to the following steps:

[0059] (1) Pretreatment

[0060] Use gasoline to wipe the surface of the aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it. The grade of the aluminum alloy is 7055;

[0061] The aluminum alloy was immersed in a 90°C sodium hydroxide solution for 20 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy was completely removed, the aluminum alloy was taken out and cleaned with pure water and dried; wherein the concentration of the sodium hydroxide solution used was 50g / L, and the concentration of the nitric acid used was 300g / L.

[0062] (2) Sulfuric acid anodizing

[0063] The aluminum alloy treated in step (1) is placed in an oxidation tank as an anode, and a sulfuric acid solution is used as a reaction solution. The aluminum alloy treated in step (1) is oxidized by a multi-stage reaction, wherein the multi-stage reaction includes a first-stage reaction, a second-stage reaction, and a third-stage reaction; the voltage of the first-stage reaction is 15V, and the reaction time is 7min; the voltage of the second-stage reaction is 20V, and the reaction time is 20min; the voltage of the third-stage reaction is 30V, and the reaction time is 1min; the aluminum alloy after the oxidation reaction is taken out of the oxidation tank, cleaned with pure water, and dried. The concentration of the sulfuric acid solution is 140g / L; the temperature of the sulfuric acid solution is 30°C.

[0064] (3) Coloring

[0065] S2, placing the aluminum alloy treated in step (2) in a coloring tank, and coloring the aluminum alloy with a black acid dye solution having a pH value of 4 as a coloring liquid, wherein the coloring time is 30 minutes; taking the aluminum alloy out of the coloring tank after the coloring is completed, cleaning it with pure water, and drying it. The colorant of the black acid dye solution is a mixture of acid black ATT and Yongguang K032 in a mass ratio of 1:1; the solvent is a mixture of ethanol, methanol and pure water in a volume ratio of 1:1:1, and the concentration of the colorant is 10g / L; the temperature of the black acid dye solution is 30°C.

[0066] (4) Surface coating

[0067] The surface modifier is coated on the surface of the aluminum alloy treated in step (3) by spraying, and the surface modifier is cured by keeping the temperature at 80°C for 12 hours, wherein the number of spraying is 4 times. The surface modifier includes silica sol and metal salts Na3VO4 and Fe2(SO4)3. The particle size range of the silica sol is 70nm, the concentration of the silica sol is 3wt%, the concentration of Na3VO4 is 1wt%; the concentration of Fe2(SO4)3 is 1wt%; the solvent of the surface modifier is a mixture of ethanol, methanol and pure water, and the volume ratio of ethanol, methanol and pure water is 1:1:1.

[0068] The high-absorption and high-emission thermal control coating on the aluminum alloy surface prepared in this embodiment has a coating thickness of 35 μm, a solar absorptivity of 0.88, an infrared emissivity of 0.87, a cross-hatch bonding strength of level 1, a vacuum condensable volatile requirement of 0.4%, and no damage or falling off occurs after 100 times of thermal cycling at -196°C to +100°C.

[0069] Comparative Example 1

[0070] Using 2024 aluminum alloy as the substrate, a comparative coating was prepared according to the following steps:

[0071] (1) Pretreatment

[0072] Use gasoline to wipe the surface of 2024 aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it;

[0073] The aluminum alloy was immersed in a 60°C sodium hydroxide solution for 30 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy was completely removed, the aluminum alloy was taken out and cleaned with pure water and dried; wherein the concentration of the sodium hydroxide solution used was 30g / L, and the concentration of the nitric acid used was 250g / L.

[0074] (2) Sulfuric acid anodizing

[0075] The aluminum alloy treated in step (1) is placed in an oxidation tank as an anode, and a sulfuric acid solution is used as a reaction solution to perform an oxidation reaction on the aluminum alloy treated in step (1), the reaction voltage is 20V, and the reaction time is 30min; the aluminum alloy after the oxidation reaction is taken out from the oxidation tank, cleaned with pure water, and dried. The concentration of the sulfuric acid solution is 120g / L; the temperature of the sulfuric acid solution is 25°C.

[0076] (3) Coloring

[0077] S2, placing the aluminum alloy treated in step (2) in a coloring tank, and coloring the aluminum alloy with a black acid dye solution having a pH value of 5 as a coloring liquid, wherein the coloring time is 8min; taking the aluminum alloy out of the coloring tank after the coloring is completed, cleaning it with pure water, and drying it. The colorant of the black acid dye solution is acid black ATT, and the solvent is a mixture of ethanol, methanol and pure water, wherein the volume ratio of ethanol, methanol to pure water is 1:1:1. The concentration of the colorant is 1g / L; and the temperature of the black acid dye solution is 30°C.

[0078] (4) Surface coating

[0079] The silica sol is coated on the surface of the aluminum alloy treated in step (3) by spraying, and is cured by keeping at 100° C. for 8 hours. The number of spraying is 5 times. The particle size range of the silica sol is 120 nm, the concentration is 1wt%, and the mixture of ethanol, methanol and pure water is 5wt%, wherein the volume ratio of ethanol, methanol and pure water is 1:1:1.

[0080] The high-absorption and high-emission thermal control coating on the aluminum alloy surface prepared in this embodiment has a coating thickness of 37 μm, a solar absorptivity of 0.83, an infrared emissivity of 0.84, a cross-hatch bonding strength of level 3, and a vacuum condensable volatile content of 0.27%. After 100 times of thermal cycling at -196°C to +100°C, local cracking of the coating occurred.

[0081] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0084] The above is a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface, characterized in that: include: S1, placing the pre-treated aluminum alloy as an anode in an oxidation tank, using a sulfuric acid solution as a reaction solution, and performing an oxidation reaction on the pre-treated aluminum alloy in a multi-stage reaction manner, wherein the multi-stage reaction includes a first-stage reaction, a second-stage reaction, and a third-stage reaction; the voltage of the first-stage reaction is 10-15V, and the reaction time is 5-10min; the voltage of the second-stage reaction is 15-20V, and the reaction time is 10-40min; the voltage of the third-stage reaction is 20-30V, and the reaction time is 0.5-5min; S2, placing the aluminum alloy treated in step S1 in a coloring tank, and coloring the aluminum alloy using a black acid dye solution with a pH value of 4-6.5 as a coloring liquid, wherein the coloring time is 10-40 minutes; S3, coating the surface modifier on the surface of the aluminum alloy treated in step S2, and obtaining a high-absorption and high-emission thermal control coating on the surface of the aluminum alloy after the surface modifier is solidified, wherein the surface modifier includes silica sol and metal salt, the particle size range of the silica sol is 50-100nm, the concentration of the silica sol is 1-5wt%, the concentration of the metal salt is 0.2-5wt%, and the metal salt includes at least one of Co(CH3COO)2, Na3VO4 and Fe2(SO4)3.

2. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: In step S1, the concentration of the sulfuric acid solution is 140-200 g / L; the temperature of the sulfuric acid solution is 20-50°C.

3. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: In step S2, the black acid dye solution includes a colorant, and the concentration of the colorant is 5-15 g / L; the temperature of the black acid dye solution is 20-50°C.

4. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 3, characterized in that: The colorant includes at least one of acid black ATT and Everlight K032.

5. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: Step S3 includes: The surface modifier is coated on the surface of the aluminum alloy treated in step S2 by spraying, and the surface modifier is cured by heat preservation at 40-100° C. for 1-15 hours, wherein the number of spraying is 4-8 times.

6. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: After the pre-treated aluminum alloy is subjected to oxidation reaction in a multi-stage reaction manner, step S1 further comprises: The aluminum alloy after the oxidation reaction is taken out from the oxidation tank, cleaned with pure water, and dried.

7. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: After the coloring process is performed using a black acid dye solution with a pH value of 4-6.5 as the coloring liquid, step S2 further includes: After dyeing, take the aluminum alloy out of the dyeing tank, clean it with pure water, and dry it.

8. The method for preparing a high-absorption and high-emission thermal control coating on an aluminum alloy surface according to claim 1, characterized in that: Before step S1, the method further includes: Use an organic solvent to wipe the surface of the aluminum alloy, remove the oil stains on the surface of the aluminum alloy and dry it; The aluminum alloy is immersed in a 60-90° C. sodium hydroxide solution for 10-70 seconds, taken out and cleaned with pure water and dried, then placed in a nitric acid solution to react until the floating film on the surface of the aluminum alloy is completely removed, the aluminum alloy is taken out and cleaned with pure water and dried to obtain the pre-treated aluminum alloy; wherein the concentration of the sodium hydroxide solution used is 10-60 g / L, and the concentration of the nitric acid used is 200-400 g / L.

9. A high-absorption and high-emission thermal control coating on the surface of aluminum alloy, characterized in that: It is prepared by the method according to any one of claims 1 to 8.