High-temperature-resistant low-absorptivity thermal control functional coating, preparation method thereof, element and spacecraft

Abstract

The application provides a high-temperature-resistant low-absorptivity thermal control functional coating, a preparation method thereof, an element and a spacecraft, and relates to the field of functional coatings. The high-temperature-resistant low-absorptivity thermal control functional coating comprises a bonding layer, a porous conduction inhibition layer and a radiation inhibition layer which are sequentially stacked; the bonding layer comprises NiCoCrAlY; the porous conduction inhibition layer comprises A2O3, Y2O3 and ZrO2, wherein A comprises one or more of Gd, Yb, Lu, Er, Eu, Nd and La; and the radiation inhibition layer comprises YCrO3 modified noble metal, YCrO3 coated noble metal, and the noble metal comprises one or more of Ag, Pt, Pd and Au. The porous conduction inhibition layer with low thermal conductivity and the radiation inhibition layer with low absorptivity (emissivity) are arranged to achieve high-temperature resistance and heat control performance with low thermal conductivity, low absorptivity (emissivity).

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional coating, in particular to a high-temperature-resistant low-absorption heat control functional coating, a preparation method thereof, a component and a spacecraft. BACKGROUND

[0002] When a spacecraft is running in space, it is not protected by the atmosphere, and the surface temperature of the spacecraft can vary by more than several hundred degrees Celsius when the sunlight is directly incident and when the spacecraft is in the shade. All components and devices on the spacecraft must be kept within a relatively constant temperature range to ensure safe and stable operation. The harsh high-low temperature alternating space environment poses a great challenge to the service of the spacecraft. Effective heat control design must be adopted to maintain the temperature variation of the components and devices of the spacecraft within the allowable range of the devices under various working conditions, and to ensure the normal operation of the spacecraft. Heat control coating is a functional coating coated on the surface of the spacecraft, which can adjust the surface heat exchange characteristics to achieve the purpose of heat control.

[0003] Currently, heat control coatings are mostly prepared from materials with low solar absorption and high infrared emissivity. Low solar absorption can reduce the surface energy absorption, and high infrared emissivity can enhance the surface heat radiation to the outside. However, according to the Boltzmann law, the emissivity of an object is equal to its absorption, and the solar radiation contains infrared radiation. Therefore, it is difficult to achieve a large difference between the solar absorption and the infrared emissivity of a material. In addition, when the spacecraft is in direct sunlight (high temperature), a coating with low solar absorption and high infrared emissivity can reduce the surface temperature. However, when the spacecraft is in the shade (low temperature), the high infrared emissivity of the coating will accelerate the heat loss of the spacecraft, thereby further reducing the surface temperature of the spacecraft, which is not conducive to heat preservation.

[0004] Therefore, there is an urgent need to provide a heat control coating to solve the above problems. SUMMARY

[0005] The present application aims to provide a high-temperature-resistant low-absorption heat control functional coating, a preparation method thereof, a component and a spacecraft. The combination of a conduction inhibition layer and a radiation inhibition layer can achieve the following effects: when the spacecraft is in direct sunlight (high temperature), the surface radiation inhibition layer reduces the surface heat absorption, and the lower conduction inhibition layer inhibits the heat conduction to the inside, preventing the spacecraft from heating up; when the spacecraft is in the shade (low temperature), the lower conduction inhibition layer inhibits the heat conduction to the outside, and the surface radiation inhibition layer reduces the surface heat loss, so that the spacecraft can maintain a stable internal temperature in a high-low temperature alternating environment.

[0006] To achieve the above purpose, the first aspect of the present application provides a high-temperature-resistant low-absorption heat control functional coating, which comprises a bonding layer, a porous conduction inhibition layer and a radiation inhibition layer arranged in sequence.

[0007] The adhesive layer comprises NiCoCrAlY;

[0008] The porous conduction inhibition layer comprises A2O3, Y2O3 and ZrO2, wherein A comprises one or more of Gd, Yb, Lu, Er, Eu, Nd and La;

[0009] The radiation inhibition layer comprises YCrO3 modified noble metal, YCrO3 coated noble metal, and the noble metal comprises one or more of Ag, Pt, Pd and Au.

[0010] Optionally, the high-temperature-resistant low-absorption heat control functional coating satisfies at least one of the following conditions:

[0011] (1) The total mass of the elements of the NiCoCrAlY is 100%, comprising:

[0012] Co 20%-25%, Cr 20%-25%, Al 5%-8%, Y 0.5%-1%, and the balance being Ni;

[0013] (2) The thickness of the adhesive layer is 50-120 μm.

[0014] Optionally, the high-temperature-resistant low-absorption heat control functional coating satisfies at least one of the following conditions:

[0015] (1) The mass ratio of the A2O3, the Y2O3 and the ZrO2 is X:Y:1-X-Y, wherein 0.05≤X≤0.15 and 0.06≤Y≤0.09;

[0016] (2) The thickness of the porous conduction inhibition layer is 150-350 μm;

[0017] (3) The porosity of the porous conduction inhibition layer is 15-35%.

[0018] Optionally, the high-temperature-resistant low-absorption heat control functional coating satisfies at least one of the following conditions:

[0019] (1) The mass ratio of YCrO3 and noble metal in the YCrO3 modified metal is 1-4:1;

[0020] (2) The thickness of the radiation inhibition layer is 30-120 μm;

[0021] (3) The noble metal comprises a flaky shape.

[0022] The second aspect of the present application provides a preparation method of the high-temperature-resistant low-absorption heat control functional coating, comprising:

[0023] adopting first plasma spraying to set the adhesive layer on the surface of the metal substrate;

[0024] a mixture powder of Al, A2O3, Y2O3 and ZrO2 is arranged on the surface of the adhesive layer by second plasma spraying to obtain a conduction inhibition layer, and the conduction inhibition layer is mixed with sodium hydroxide to obtain a porous conduction inhibition layer;

[0025] YCrO3 modified noble metal paint is sprayed on the surface of the porous conduction inhibition layer to obtain a radiation inhibition layer by first curing.

[0026] Optionally, the preparation method of the high-temperature-resistant and low-absorption heat control functional coating satisfies at least one of the following conditions:

[0027] (1) the spraying distance of the first plasma spraying is 140 mm-220 mm, the argon flow rate is 30-40 slpm, the hydrogen flow rate is 6-10 slpm, and the power is 30-40 kW;

[0028] (2) the volume ratio of the Al to the mixture powder is 1:6-9;

[0029] (3) the spraying distance of the second plasma spraying is 90 mm-150 mm, the argon flow rate is 36-44 slpm, the hydrogen flow rate is 6-13 slpm, and the power is 35-43 kW;

[0030] (4) the concentration of sodium hydroxide is 5-10 mol / L;

[0031] (5) the preparation method of the YCrO3 modified noble metal paint comprises:

[0032] first ball milling of noble metal powder to obtain flaky noble metal, mixing the flaky noble metal with YCrO3 powder, second ball milling to obtain YCrO3 coated flaky noble metal, and mixing the binder, water and the YCrO3 coated flaky noble metal;

[0033] (6) the temperature of the first curing is 160-250°C, and the time is 1-2 h.

[0034] Optionally, the preparation method of the high-temperature-resistant and low-absorption heat control functional coating satisfies at least one of the following conditions:

[0035] (1) the grinding material of the first ball milling comprises zirconia balls, the ball-to-material mass ratio is 2-3:1, and the ball milling time is 6-8 h;

[0036] (2) the second ball milling time is 8-12 h;

[0037] (3) the mass ratio of the binder, the water and the YCrO3 coated flaky noble metal is 0.1-0.4:0.4-0.7:1;

[0038] (4) the adhesive comprises aluminum dihydrogen phosphate.

[0039] Optionally, before the YCrO3 modified noble metal coating is sprayed, the porous conduction inhibition layer is also subjected to sealing treatment.

[0040] The sealing treatment comprises: mixing YCrO3 powder, noble metal powder, adhesive and water to obtain sealing coating; and spraying the sealing coating on the surface of the porous conduction inhibition layer to perform second solidification.

[0041] The third aspect of the application provides an element comprising a metal substrate and a coating layer arranged on the surface of the metal substrate, wherein the coating layer comprises the high-temperature-resistant low-absorptivity thermal control functional coating or is prepared by the preparation method of the high-temperature-resistant low-absorptivity thermal control functional coating.

[0042] The fourth aspect of the application provides a spacecraft comprising the element.

[0043] Compared with the prior art, the application has the following beneficial effects:

[0044] The high-temperature-resistant low-absorptivity thermal control functional coating provided by the application comprises a porous conduction inhibition layer with low thermal conductivity and a radiation inhibition layer with low absorptivity (emissivity). The porous conduction inhibition layer is made of rare earth doped zirconia material with low thermal conductivity. The addition of rare earth elements introduces high concentrations of point defects (rare earth solute ions and oxygen vacancies introduced by the rare earth solute ions) to cause extremely strong scattering of phonons, the main carrier of heat conduction, thereby greatly reducing the thermal conductivity of the material. The thermal conductivity of the coating layer is related to the intrinsic properties of the material and the structure of the coating layer. The porous structure further reduces the thermal conductivity of the coating layer. The low-absorptivity (emissivity) layer is made of YCrO3 modified noble metal. Noble metal materials usually have extremely low absorptivity (emissivity), but once oxidized, the emissivity will increase sharply. The application coats the noble metal with YCrO3 to prevent oxidation of the noble metal. Moreover, the YCrO3 material has excellent high-temperature resistance and can protect the surface of the metal material. At the same time, the material has a low infrared emissivity, which can ensure that the emissivity value of the composite powder remains at a low level.

[0045] The preparation method of the high-temperature-resistant low-absorptivity thermal control functional coating provided by the application dissolves Al in the coating layer with an alkali solution to form a porous structure coating, thereby further reducing the thermal conductivity of the coating layer. The preparation method is simple to operate and the raw materials are easy to obtain.

[0046] The element and the spacecraft provided by the application can be prepared on the surface of a metal material and have excellent heat control performance of high-temperature resistance, low heat conduction and low absorption rate, so that the element and the spacecraft can safely and effectively serve in a severe high-low temperature alternating space environment. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope of the application.

[0048] Figure 1 SEM diagram of the high-temperature-resistant low-absorption-rate heat control functional coating provided for embodiment 1;

[0049] Figure 2 Structural schematic diagram of the high-temperature-resistant low-absorption-rate heat control functional coating provided for embodiment 1.

[0050] Main element symbol explanation:

[0051] 100-bonding layer; 200-porous conduction inhibition layer; 300-radiation inhibition layer; 400-metal substrate. DETAILED DESCRIPTION

[0052] It should be noted that there are three ways of heat propagation, namely heat conduction, heat convection and heat radiation. In the space vacuum environment, there is no heat convection because of the lack of fluid medium.

[0053] The application realizes heat control of the spacecraft in a cold-hot alternating environment by coating a high-temperature-resistant low-absorption-rate heat control functional coating on the outer surface of the spacecraft and the element, so that the spacecraft is in a relatively stable temperature range to ensure normal operation.

[0054] First, the scheme provided by the application is explained in more detail as follows:

[0055] The application provides a high-temperature-resistant low-absorption-rate heat control functional coating, which comprises a bonding layer, a porous conduction inhibition layer and a radiation inhibition layer which are sequentially stacked.

[0056] The bonding layer comprises NiCoCrAlY;

[0057] The porous conduction inhibition layer comprises A2O3, Y2O3 and ZrO2, wherein A comprises one or more of Gd, Yb, Lu, Er, Eu, Nd and La;

[0058] It is worth noting that ZrO2 has extremely low intrinsic thermal conductivity and excellent fracture toughness, which provides advantages for constructing thermal conduction inhibition coatings under extreme thermal cycling conditions; Y2O3 forms a stable cubic phase structure with zirconia, providing high-temperature phase stability for the coating, which is a prerequisite for the application of the coating in high-temperature environments; rare earth ions have greater mass and larger ionic radius, and their doping can cause strong lattice distortion, greatly enhancing phonon scattering effects and effectively blocking the conduction of lattice thermal vibrations (i.e. phonon heat conduction), thereby greatly reducing the thermal conductivity of the material; at the same time, appropriate rare earth doping can have a synergistic effect with Y 3+ 2O3, further enhancing the stability of the cubic phase, avoiding phase separation or new phase formation that may be caused by the introduction of rare earth elements, and ensuring the reliability of the material; this "synergistic modification" effect enables the coating to maintain excellent stability while achieving excellent thermal conduction inhibition performance.

[0059] The radiation inhibition layer includes YCrO3 modified noble metal, YCrO3 coated noble metal, and the noble metal includes one or more of Ag, Pt, Pd, and Au.

[0060] It is worth noting that noble metal materials with excellent high-temperature oxidation resistance are selected as low-absorption (emission) rate materials, and their morphology and surface are modified, and the noble metal is coated with YCrO3 to protect the surface of the metal material.

[0061] It is also worth noting that the bonding layer ensures the durability of the system, providing a guarantee for the stable existence of the multi-layer structure; the conduction inhibition layer and the radiation inhibition layer achieve "segmented resistance" and "functional complementation" in the heat control path - the conduction inhibition layer is responsible for solving internal phonon heat conduction, while the radiation inhibition layer solves surface photon heat conduction. Three layers progress one by one, support each other, and together form an integrated thermal control system that still has ultra-low heat control in high and low temperature alternating environments.

[0062] In some embodiments, the high-temperature-resistant low-absorption rate thermal control functional coating satisfies at least one of the following conditions:

[0063] (1) The total mass of the elements of the NiCoCrAlY is 100%, including:

[0064] Co 20%-25%, Cr 20%-25%, Al 5%-8%, Y 0.5%-1%, and the balance being Ni;

[0065] Optionally, the total mass of elements of the NiCoCrAlY is 100%, Co can be 20%, 21%, 22%, 23%, 24%, 25% or any value between 20% and 25%, Cr can be 20%, 21%, 22%, 23%, 24%, 25% or any value between 20% and 25%, Al can be 5%, 6%, 7%, 8% or any value between 5% and 8%, Y can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or any value between 0.5% and 1%, and the balance is Ni;

[0066] (2) the thickness of the bonding layer is 50-120 μm.

[0067] Optionally, the thickness of the bonding layer can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or any value between 50 μm and 120 μm.

[0068] It should be noted that the bonding layer provides long-term "life" for the entire coating system, ensures firm bonding with the substrate and oxidation / corrosion resistance by forming a dense and excellent adhesion thermally grown oxide (TGO) layer, provides a solid foundation guarantee for the stable existence of the upper ceramic functional layer, and is the guarantee of system durability.

[0069] In some embodiments, the high-temperature-resistant low-absorption heat control functional coating satisfies at least one of the following conditions:

[0070] (1) the mass ratio of the A2O3, the Y2O3 and the ZrO2 is X:Y:1-X-Y, wherein 0.05≤X≤0.15 and 0.06≤Y≤0.09;

[0071] Optionally, X can be 0.05, 0.1, 0.15 or any value between 0.05 and 0.15, and Y can be 0.06, 0.07, 0.08, 0.09 or any value between 0.06 and 0.09;

[0072] It should be noted that 6-9% of Y2O3 is required to form a non-phase change, highly stable full-cubic phase zirconia. A content that is too low cannot completely stabilize the cubic phase, resulting in martensitic phase change of the material during cold and hot alternation, causing the coating to crack and peel off. A content that is too high will form a yttrium-rich phase that is not conducive to mechanical properties, and excessive Y 3+The solid solution of Y2O3 will excessively reduce the fracture toughness of the material, and the preferred 6-9% Y2O3 provides the coating with indispensable high phase stability and toughness in the service environment. The A2O3 content of 5-15% is far lower than the required concentration to form rare earth stabilized zirconium oxide (such as A2Zr2O7), to ensure that rare earth atoms exist in the form of substitutional solid solution in the Y-ZrO2 lattice, rather than forming a second phase. The addition of more than 5% of rare earth elements with larger ionic radius introduces strong lattice strain and stress field in the lattice, thereby causing strong scattering of heat transfer phonons, which can further lower the thermal conductivity of the coating;

[0073] (2) The thickness of the porous conduction inhibition layer is 150-350 μm;

[0074] Optionally, the thickness of the porous conduction inhibition layer can be 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, or any value between 150-350 μm;

[0075] (3) The porosity of the porous conduction inhibition layer is 15-35%.

[0076] Optionally, the porosity of the porous conduction inhibition layer can be 15%, 20%, 25%, 30%, 35%, or any value between 15-35%.

[0077] It should be noted that the setting of 15-35% porosity is based on the delicate balance of the thermal insulation, strength, and durability of the conduction inhibition layer. The pores in the coating can effectively scatter phonons (the main carrier of heat conduction), greatly reducing the thermal conductivity of the coating. A porosity higher than 15% can provide a significantly better thermal insulation effect than a dense coating. If the porosity of the coating is lower than 15%, the coating is too dense, the thermal conductivity will increase, and it cannot effectively block the transfer of heat by conduction. In addition, the ceramic layer is highly brittle and has a very low strain tolerance. In the cold and hot cycle, the stress cannot be released through microstructure adjustment, and it is easy to produce and expand through cracks, leading to early peeling and failure of the coating. If the porosity of the coating exceeds 35%, although the thermal conduction inhibition performance may be better, the layer bonding strength, hardness, and elastic modulus will decrease below the critical value, and it is easy to break and fall off in service.

[0078] In some embodiments, the high-temperature-resistant low-absorption rate thermal control functional coating satisfies at least one of the following conditions:

[0079] (1) The mass ratio of YCrO3 to noble metal in the YCrO3 modified metal is 1-4:1;

[0080] Optionally, the mass ratio of YCrO3 to noble metal in the YCrO3 modified metal can be 1:1, 1:2, 1:3, 1:4, or any value between 1-4:1;

[0081] (2) the thickness of the radiation suppression layer is 30-120 μm;

[0082] Optionally, the thickness of the radiation suppression layer can be 30 μm, 60 μm, 90 μm, 120 μm or any value between 30-120 μm;

[0083] (3) the noble metal comprises a sheet shape.

[0084] It should be noted that the coating prepared by using the sheet-shaped noble metal filler can further reduce the infrared emissivity of the coating, so that the outermost layer of the coating has high temperature resistance and low infrared emissivity, and can effectively achieve thermal radiation suppression.

[0085] The second aspect of the present application provides a preparation method of the high-temperature-resistant and low-absorptivity thermal control functional coating, comprising:

[0086] a bonding layer is arranged on the surface of the metal substrate by first plasma spraying;

[0087] a mixed powder of Al, A2O3, Y2O3 and ZrO2 is arranged on the surface of the bonding layer by second plasma spraying to obtain a conduction suppression layer, and the conduction suppression layer is mixed with sodium hydroxide to obtain a porous conduction suppression layer;

[0088] a YCrO3 modified noble metal coating is sprayed on the surface of the porous conduction suppression layer to obtain a radiation suppression layer after first solidification.

[0089] In some embodiments, the preparation method of the high-temperature-resistant and low-absorptivity thermal control functional coating satisfies at least one of the following conditions:

[0090] (1) the spraying distance of the first plasma spraying is 140-220 mm, the argon flow rate is 30-40 slpm, the hydrogen flow rate is 6-10 slpm, and the power is 30-40 kW;

[0091] Optionally, the spraying distance of the first plasma spraying can be 140 mm, 150 mm, 200 mm, 220 mm or any value between 140-220 mm, the argon flow rate can be 30 slpm, 35 slpm, 40 slpm or any value between 30-40 slpm, the hydrogen flow rate can be 6 slpm, 7 slpm, 8 slpm, 9 slpm, 10 slpm or any value between 6-10 slpm, and the power can be 30 kW, 35 kW, 40 kW or any value between 30-40 kW;

[0092] (2) the volume ratio of the Al to the mixed powder is 1:6-9;

[0093] Optionally, the volume ratio of Al and the mixed powder can be 1:6, 1:7, 1:8, 1:9, or any value between 1:6 and 1:9.

[0094] (3) The spraying distance of the second plasma spraying is 90-150 mm, the argon flow rate is 36-44 slpm, the hydrogen flow rate is 6-13 slpm, and the power is 35-43 kW.

[0095] Optionally, the spraying distance of the second plasma spraying can be 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, or any value between 90 mm and 150 mm, the argon flow rate can be 36 slpm, 38 slpm, 40 slpm, 42 slpm, 44 slpm, or any value between 36 slpm and 44 slpm, the hydrogen flow rate can be 6 slpm, 8 slpm, 10 slpm, 13 slpm, or any value between 6 slpm and 13 slpm, and the power can be 35 kW, 40 kW, 43 kW, or any value between 35 kW and 43 kW.

[0096] (4) The concentration of sodium hydroxide is 5-10 mol / L.

[0097] Optionally, the concentration of sodium hydroxide can be 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, or any value between 5 mol / L and 10 mol / L.

[0098] (5) The preparation method of the YCrO3 modified noble metal coating comprises:

[0099] The noble metal powder is first ball milled to obtain flaky noble metal, the flaky noble metal and YCrO3 powder are mixed and second ball milled to obtain YCrO3 coated flaky noble metal, and the binder, water, and the YCrO3 coated flaky noble metal are mixed.

[0100] (6) The temperature of the first solidification is 160-250℃, and the time is 1-2 h.

[0101] Optionally, the temperature of the first solidification can be 160℃, 200℃, 250℃, or any value between 160℃ and 250℃, and the time can be 1 h, 1.5 h, 2 h, or any value between 1 h and 2 h.

[0102] In some embodiments, the preparation method of the high-temperature-resistant low-absorption heat control functional coating satisfies at least one of the following conditions:

[0103] (1) the grinding material of the first ball milling includes zirconia balls, the mass ratio of ball to material is 2-3:1, and the ball milling time is 6-8h;

[0104] Optionally, the mass ratio of ball to material can be 2:1, 2.5:1, 3:1 or any value between 2-3:1, and the ball milling time can be 6h, 7h, 8h or any value between 6-8h;

[0105] (2) the second ball milling time is 8-12h;

[0106] Optionally, the second ball milling time can be 8h, 10h, 12h or any value between 8-12h;

[0107] (3) the mass ratio of the binder, the water and the YCrO3 coated flaky noble metal is 0.1-0.4:0.4-0.7:1;

[0108] Optionally, the mass ratio of the binder, the water and the YCrO3 coated flaky noble metal can be 0.1:0.4:1, 0.4:0.4:1, 0.1:0.7:1, 0.4:0.7:1 or any value between 0.1-0.4:0.4-0.7:1;

[0109] (4) the binder includes aluminum dihydrogen phosphate.

[0110] In some embodiments, before the YCrO3 modified noble metal coating is sprayed, the porous conduction inhibition layer is also subjected to a sealing treatment;

[0111] It should be noted that if the YCrO3 modified noble metal coating is directly sprayed on the surface of the porous conduction inhibition layer to prepare a radiation inhibition layer, since the YCrO3 modified noble metal coating penetrates into the pores, the surface roughness of the cured radiation inhibition layer is large, and the infrared emissivity of the radiation inhibition layer is proportional to the roughness, thus it is not conducive to achieving the low infrared emissivity of the high-temperature-resistant low-absorptivity thermal control functional coating, i.e., the radiation inhibition performance. Therefore, before the radiation inhibition layer is prepared, a material with the same element composition as the radiation inhibition layer is used, but the sealing coating formed by the YCrO3 powder and the noble metal powder is used to perform a sealing treatment on the surface area of the porous conduction inhibition layer to form a thin surface-dense transition layer. The transition layer has low thermal conductivity and low infrared emissivity characteristics, and can ensure that the subsequent outermost thermal radiation inhibition has a relatively smooth surface, thereby having a lower infrared absorptivity (emissivity).

[0112] The sealing treatment includes: mixing YCrO3 powder, noble metal powder, a binder and water to obtain a sealing coating; and spraying the sealing coating on the surface of the porous conduction inhibition layer to perform a second curing.

[0113] It should be noted that when the coating is in the direct sunlight, the outermost low-absorption layer (radiation suppression layer) can suppress the radiation absorption of heat by the spacecraft or element, and the lower porous conduction suppression layer (low-thermal-conductivity layer) can suppress the heat conduction from the surface to the interior, thereby suppressing the temperature rise in the interior of the spacecraft or element; when the coating is in the back sun, the porous conduction suppression layer (low-thermal-conductivity layer) can suppress the heat conduction from the interior of the spacecraft or element to the outer surface, and the outermost low-absorption layer (radiation suppression layer) can suppress the radiation loss of heat of the spacecraft, thereby suppressing the temperature drop in the interior of the spacecraft or element; in general, through the double suppression of heat conduction and heat radiation, the heat exchange between the interior and the exterior of the spacecraft is reduced, so that when the temperature of the outer surface of the spacecraft alternates between cold and hot, the temperature in the interior of the spacecraft is maintained in a relatively stable range.

[0114] The third aspect of the present application provides an element comprising a metal substrate and a coating arranged on the surface of the metal substrate, wherein the coating comprises the high-temperature-resistant low-absorption heat control functional coating or is prepared by the preparation method of the high-temperature-resistant low-absorption heat control functional coating.

[0115] The fourth aspect of the present application provides a spacecraft comprising the element.

[0116] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0117] Example 1

[0118] The present embodiment provides a high-temperature-resistant low-absorption heat control functional coating, which comprises a bonding layer 100, a porous conduction suppression layer 200 and a radiation suppression layer 300 arranged in sequence.

[0119] The thickness of the bonding layer 100 is 100 μm, and the bonding layer 100 comprises NiCoCrAlY, wherein the total mass of the elements of the NiCoCrAlY is 100%, Co is 25%, Cr is 20%, Al is 5%, Y is 0.8%, and the balance is Ni;

[0120] The thickness of the porous conduction suppression layer 200 is 350 μm, and the porosity is 25%, and the porous conduction suppression layer 200 comprises A2O3, Y2O3 and ZrO2, wherein A comprises Gd, and the mass ratio of A2O3, Y2O3 and ZrO2 is 0.08:0.08:0.84;

[0121] The thickness of the radiation suppression layer 300 is 50 μm, and the radiation suppression layer 300 comprises YCrO3 modified noble metal, YCrO3 coated flaky noble metal, and the noble metal comprises Pt, and the mass ratio of YCrO3 to the noble metal is 3:1.

[0122] The application comprises a preparation method of a high-temperature-resistant low-absorption heat control functional coating, and the specific steps are as follows:

[0123] S1: The NiCoCrAlY alloy powder is arranged on the surface of the metal substrate (aluminum alloy substrate) 400 by using first plasma spraying to obtain the bonding layer 100, the spraying distance of the first plasma spraying is 160 mm, the argon flow rate is 36 slpm, the hydrogen flow rate is 8 slpm, and the power is 38 kW;

[0124] S2: The mixed powder of Al, A2O3, Y2O3 and ZrO2 is arranged on the surface of the bonding layer 100 by using second plasma spraying to obtain the conduction suppression layer, the volume ratio of Al to the mixed powder is 1:6, the spraying distance of the second plasma spraying is 110 mm, the argon flow rate is 40 slpm, the hydrogen flow rate is 12 slpm, and the power is 39 kW;

[0125] S4: The conduction suppression layer is soaked in a sodium hydroxide solution with a concentration of 5 mol / L for 5 h to obtain the porous conduction suppression layer 200;

[0126] S5: The YCrO3 powder, the noble metal powder Pt, the aluminum dihydrogen phosphate and water are mixed according to the mass ratio of 0.5:0.5:2:4 to obtain a sealing coating, the sealing coating is sprayed on the surface of the porous conduction suppression layer by using an air spray gun, and the sealing coating is cured at 150℃ for 1 h to form a 10 μm permeation layer on the inside of the upper side of the porous conduction suppression layer for sealing treatment;

[0127] S6: The noble metal powder is first ball milled by using zirconium oxide balls as the milling material, the mass ratio of the balls to the material is 3:1, and the ball milling time is 8 h to obtain flaky noble metal, the flaky noble metal and the YCrO3 powder are mixed and second ball milled for 8 h to obtain YCrO3 coated flaky noble metal, the aluminum dihydrogen phosphate, water and the YCrO3 coated flaky noble metal are mixed according to the mass ratio of 0.4:0.7:1 to obtain YCrO3 modified noble metal coating, the YCrO3 modified noble metal coating is sprayed on the surface of the material prepared in S5, and the YCrO3 modified noble metal coating is cured at 200℃ for 1 h to obtain the radiation suppression layer 300.

[0128] The SEM of the high-temperature-resistant low-absorption heat control functional coating is shown in Figure 1 , and the structural diagram is shown in Figure 2 .

[0129] Example 2

[0130] The difference from Example 1 is that: no S5 step is performed, i.e., no sealing treatment is performed.

[0131] Comparative Example 1

[0132] The difference from Example 1 is that: no adhesive layer is provided.

[0133] Comparative Example 2

[0134] The difference from Example 1 is that: no porous conduction inhibition layer is provided.

[0135] Comparative Example 3

[0136] The difference from Example 1 is that: no radiation inhibition layer is provided.

[0137] Comparative Example 4

[0138] The difference from Example 1 is that: the porous conduction inhibition layer is not provided with a porous structure, specifically:

[0139] The mixed powder of A2O3, Y2O3 and ZrO2 is provided on the surface of the adhesive layer by second plasma spraying to obtain a conduction inhibition layer, and then the preparation of the radiation inhibition layer is directly performed.

[0140] Comparative Example 5

[0141] The difference from Example 1 is that: the porous conduction inhibition layer does not add Y2O3.

[0142] Comparative Example 6

[0143] The difference from Example 1 is that: the porous conduction inhibition layer does not add A2O3.

[0144] Comparative Example 7

[0145] The difference from Example 1 is that: in the S6 step, the noble metal, YCrO3, aluminum dihydrogen phosphate and water are directly mixed to prepare a YCrO3-noble metal coating, and then spraying is performed for preparation.

[0146] The high-temperature-resistant low-absorption heat control functional coating provided by the above examples and comparative examples is subjected to performance testing, and the specific test results are shown in Table 1.

[0147] Table 1 Performance Test

[0148]

[0149] Analysis:

[0150] From the above results, it can be seen that, in Example 2, no sealing treatment is performed, the surface roughness of the radiation suppression layer after curing is high, the infrared emissivity of the coating is high, which is not conducive to the radiation suppression function; no adhesive layer is set, the bonding strength of the subsequent coating and the substrate is low, and peeling occurs during the spraying process; no porous conduction suppression layer is set, the overall thermal conductivity of the coating is high due to the absence of low thermal conductivity materials and the extremely high thermal conductivity of the metal materials in the radiation suppression layer, and the coating cannot play the heat conduction suppression performance; no radiation suppression layer is set, the outermost side of the coating is the porous ceramic layer, which leads to extremely high infrared emissivity of the coating, and the coating does not have the radiation suppression function; the porous conduction suppression layer is not provided with a porous structure, the thermal conductivity of the dense structure coating is higher than that of the porous structure coating, and the conduction suppression is poor; the porous conduction suppression layer does not add Y2O3, and the coating peels off during the spraying process due to the phase change of zirconium oxide; the porous conduction suppression layer does not add A2O3, and the strong scattering of heat phonons by rare earth elements is absent, which makes the thermal conductivity of the coating high and the conduction suppression of the coating poor; the non-flaky noble metal is used to prepare the radiation suppression layer, and the infrared emissivity of the coating is higher than that of the flaky coating, which is not conducive to the radiation suppression function of the coating.

[0151] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0152] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, any one of the claimed embodiments can be used in any combination. The information disclosed in the BACKGROUND section is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A high-temperature resistant, low-absorption thermal control coating, characterized in that, It includes an adhesive layer, a porous conduction suppression layer, and a radiation suppression layer stacked sequentially; The adhesive layer comprises NiCoCrAlY; The porous conduction suppression layer comprises A2O3, Y2O3 and ZrO2, wherein A includes one or more of Lu, Er, Eu, Nd and La; The radiation suppression layer comprises YCrO3 coated with a noble metal, wherein the noble metal comprises one or more of Ag, Pt, Pd and Au; The total elemental mass of the NiCoCrAlY is calculated as 100%, including: Co 20%-25%, Cr 20%-25%, Al 5%-8%, Y 0.5%-1%, balance Ni; The mass ratio of A2O3, Y2O3 and ZrO2 is X:Y:1-XY, where 0.05≤X≤0.15 and 0.06≤Y≤0.

09. The porosity of the porous conduction suppression layer is 15-35%; The mass ratio of YCrO3 to noble metal in the YCrO3-coated noble metal is 1-4:1; The thickness of the radiation suppression layer is 30-120 μm.

2. The high-temperature resistant, low-absorption thermal control coating according to claim 1, characterized in that, The thickness of the adhesive layer is 50-120 μm.

3. The high-temperature resistant, low-absorption thermal control coating according to claim 1, characterized in that, The thickness of the porous conduction suppression layer is 150-350 μm.

4. The high-temperature resistant, low-absorption thermal control coating according to claim 1, characterized in that, The precious metals include those in sheet form.

5. A method for preparing a high-temperature resistant, low-absorption thermal control functional coating according to any one of claims 1-4, characterized in that, include: An adhesive layer is formed on the surface of a metal substrate by first plasma spraying; A mixed powder of Al, A2O3, Y2O3 and ZrO2 is applied to the surface of the adhesive layer by a second plasma spraying process to obtain a conduction inhibition layer. The conduction inhibition layer is then mixed with sodium hydroxide to obtain a porous conduction inhibition layer. The YCrO3-coated noble metal coating is sprayed onto the surface of the porous conduction suppression layer and then cured for the first time to obtain the radiation suppression layer.

6. The method for preparing the high-temperature resistant, low-absorption thermal control functional coating according to claim 5, characterized in that... The first plasma spraying has a spraying distance of 140mm-220mm, an argon flow rate of 30-40slpm, a hydrogen flow rate of 6-10slpm, and a power of 30-40kW. The volume ratio of Al to the mixed powder is 1:6-9; The second plasma spraying has a spraying distance of 90mm-150mm, an argon flow rate of 36-44 slpm, a hydrogen flow rate of 6-13 slpm, and a power of 35-43kW. The concentration of sodium hydroxide is 5-10 mol / L; The preparation method of the YCrO3-coated noble metal coating includes: The precious metal powder is first ball-milled to obtain flake-shaped precious metal. The flake-shaped precious metal is mixed with YCrO3 powder and then ball-milled a second time to obtain YCrO3-coated flake-shaped precious metal. The binder, water and the YCrO3-coated flake-shaped precious metal are then mixed. The first curing temperature is 160-250℃, and the time is 1-2 hours.

7. The method for preparing the high-temperature resistant, low-absorption thermal control functional coating according to claim 6, characterized in that, The abrasive used in the first ball mill includes zirconia balls, with a ball-to-material mass ratio of 2-3:1, and a milling time of 6-8 hours. The second ball milling time is 8-12 hours; The mass ratio of the adhesive, the water, and the YCrO3-coated flake noble metal is 0.1-0.4:0.4-0.7:

1. The adhesive includes aluminum dihydrogen phosphate.

8. The method for preparing the high-temperature resistant, low-absorption thermal control functional coating according to claim 5, characterized in that, Before spraying the YCrO3-coated precious metal coating, the porous conduction inhibition layer is also sealed. The sealing process includes: mixing YCrO3 powder, precious metal powder, adhesive and water to obtain a sealing coating; spraying the sealing coating onto the surface of the porous conduction inhibition layer and performing a second curing.

9. A component, characterized in that, It includes a metal substrate and a coating disposed on the surface of the metal substrate, wherein the coating includes the high-temperature resistant and low-absorption-rate thermal control functional coating according to any one of claims 1-4 or the high-temperature resistant and low-absorption-rate thermal control functional coating prepared by the preparation method of the high-temperature resistant and low-absorption-rate thermal control functional coating according to any one of claims 5-8.

10. A spacecraft, characterized in that, Includes the element as described in claim 9.

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