Doped M-phase VO2 core-shell particles, intelligent radiation coating and preparation method

Abstract

The present invention provides doped M-phase VO2 core-shell particles, an intelligent radiation coating, and a preparation method. The intelligent radiation coating comprises a base layer and a resin layer; the upper surface of the resin layer is uniformly dispersed with horizontally oriented flaky doped VO2(M) core-shell particles; the flaky doped VO2(M) core-shell particles comprise flaky aluminum powder as the core material, an X material as the intermediate layer, and a doped VO2 shell as the surface layer. The doped VO2(M) core-shell particles, Al@X@VO2(M), are used to achieve a transition between infrared light reflection and absorption properties; incident infrared waves induce a resonant response, resulting in enhanced absorption of the coating and correspondingly enhanced emissivity, achieving a cooling effect. The present invention features intelligent dynamic temperature control, a simple structure, ease of large-scale preparation, and zero energy consumption, making it of great significance for solving the problem of over-cooling and alleviating the urban heat island effect. Furthermore, it has potential for application in fields such as infrared camouflage.

Description

Technical Field

[0001] The invention relates to an intelligent radiation coating and a preparation method thereof, and belongs to the field of photothermal regulation and phase change temperature control. Background Art

[0002] With the continuous acceleration of urbanization, the urban heat island effect is becoming increasingly severe. This not only leads to a continuous rise in urban temperatures, but also a sharp increase in the energy consumption required for cooling indoor temperatures. Traditional cooling methods, based on the principles of heat convection and heat conduction, while effective in reducing temperatures, also bring serious problems such as high energy consumption, environmental pollution, and greenhouse gas emissions. These drawbacks not only exacerbate the urban heat island effect but also form a vicious cycle that is difficult to break, resulting in a persistent negative impact on the environment. Therefore, how to solve this environmental problem has become a critical issue that requires urgent attention in contemporary society.

[0003] Against this backdrop, radiative cooling technology, as an innovative thermal management method, offers new potential for addressing environmental challenges with its unique advantages of zero energy consumption and zero emissions. Unlike traditional cooling methods, radiative cooling eliminates reliance on electricity, refrigerants, or mechanical components. Instead, it dissipates heat naturally by directly emitting infrared waves. This process, without the intervention of any media, demonstrates exceptional environmental friendliness and potential for application. Furthermore, radiative cooling technology has even expanded into space, providing efficient cooling solutions for spacecraft and demonstrating its broad application potential in diverse environmental conditions. However, despite its commercialization, radiative cooling products still face a key challenge: overcooling. During winter months or periods when additional cooling is not required, passive radiative cooling devices are unable to intelligently sense and adapt to changes in ambient temperature and continue to radiate heat. This not only increases the heating burden but also wastes energy. This limitation restricts the practical application of radiative cooling technology in mitigating the urban heat island effect.

[0004] In order to overcome this challenge, future development should focus on improving the intelligence level of radiant cooling devices. Variable emissivity (radiation) intelligent temperature control materials can automatically change their own radiation properties according to internal and external environment / temperature changes, realize intelligent regulation of heat transfer with the external environment, and achieve on-demand cooling. In this way, it can not only effectively reduce the urban heat island burden, but also promote the efficient use and sustainable development of energy, and provide technical support for building a greener and more energy-saving urban environment. At the same time, this also opens up broad prospects for the application of radiant cooling technology in more fields, making it an important force in promoting sustainable social development. Summary of the Invention

[0005] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide an intelligent radiation coating and a preparation method thereof to address the problem that the radiation characteristics of traditional radiation refrigeration materials are fixed and cannot be changed with changes in the environment. By coating VO2 with thermoinduced phase change properties on flaky aluminum powder and further preparing an Al@X@VO2 coating with directional floating arrangement characteristics, it can achieve variable emissivity modulation performance in the infrared band (2.5~14μm) (emissivity increases with increasing temperature), thereby obtaining an intelligent coating material with adjustable thermal control characteristics.

[0006] In order to achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows:

[0007] The first object of the present invention is to provide a smart radiation coating comprising a substrate layer 5 and a resin layer 1 above the substrate layer 5; the upper surface of the resin layer 1 is uniformly dispersed with horizontally oriented flake-shaped doped VO2(M) core-shell particles Al@X@VO2(M);

[0008] The flake-doped VO2(M) core-shell particles Al@X@VO2(M) have a core material of flaky aluminum powder 2 with a reflectivity greater than 90%, an intermediate layer of X material 3 with an infrared transmittance greater than 95%, and a surface layer of doped VO2 shell 4. The X material 3 is calcium fluoride, zinc sulfide, zinc selenide, or barium fluoride.

[0009] Horizontally oriented doped VO2(M) core-shell particles, Al@X@VO2(M), are used to achieve the transition between infrared light reflection and absorption properties.

[0010] Below the phase transition temperature, the permeability of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating; above the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell transforms into M phase, i.e. metallic phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

[0011] As a preferred embodiment, the particle size of the flaky aluminum powder 2 is 5 to 15 μm;

[0012] And / or the shell thickness of the X material 3 is 300nm-1000nm.

[0013] As a preferred embodiment, in the smart radiation coating, the thickness of the VO2 shell layer 4 is 20nm-60nm.

[0014] As a preferred embodiment, in the smart radiation coating, the VO2 shell layer 4 is doped with tungsten, molybdenum and boron elements to reduce its phase transition temperature.

[0015] As a preferred embodiment, in the intelligent radiation coating, the base layer 5 is a copper sheet, a flexible tin foil, a textile cloth, a steel plate or an aluminum alloy plate.

[0016] A second object of the present invention is to provide a method for preparing doped M-phase VO2 core-shell particles, comprising the following steps:

[0017] Step 1: Prepare flaky aluminum powder with a particle size of 5 to 15 μm for later use;

[0018] Step 2: Using atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a thickness of 300 nm to 1000 nm of X material to obtain flaky Al@X core-shell particles;

[0019] Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition:

[0020] (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic layer deposition equipment. Then, raise the chamber temperature to the set value. While filling with argon and maintaining a certain pressure, rotate the chamber to stir the powder and begin growing the coating layer by atomic layer deposition (ALD).

[0021] (3.2) First, a vanadium source and a dopant are introduced and allowed to react for a certain period of time with the –OH groups on the surface of the Al@X core-shell particle substrate. Then, a carrier gas N2 is introduced to remove the methane byproduct generated in this reaction.

[0022] (3.3) Water vapor is then introduced into the cavity to fully react with the –CH3 on the surface. The carrier gas N2 is then introduced again to remove the byproduct CH4. This constitutes one cycle. Al@X@VOx core-shell particles with different shell thicknesses can be obtained by setting different numbers of cycles.

[0023] Step 4: Al@X@VO prepared in step 3 x The particles are calcined in a certain atmosphere to promote VO x The shell transforms to the M phase to obtain doped VO2(M) core-shell particles;

[0024] The atmosphere calcination in step 4 is divided into two stages: the first stage is to keep the temperature at 550°C for 2 hours under 99.99% pure nitrogen;

[0025] The second stage is to keep the temperature at 400-650°C for 10-30 minutes under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

[0026] As a preferred embodiment, in the method for preparing doped M-phase VO2 core-shell particles, the chamber temperature in step (3.1) is set to 150-200°C;

[0027] And / or in step (3.2), the vanadium source is triisopropoxyvanadium oxide, and the dopant is ammonium molybdate, sodium tungstate or boric acid.

[0028] And / or the cycle period in step (3.3) is 400-2000 times.

[0029] The third object of the present invention is to provide a doped M-phase VO2 core-shell particle obtained by the above-mentioned preparation method.

[0030] A fourth object of the present invention is to provide a method for preparing a smart radiation coating, which comprises:

[0031] First, a certain amount of compound solvent is taken, and a resin with a solid content of 50% in the compound solvent is added and stirred evenly in a dispersant; secondly, a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 6 or 7 and a certain amount of floating agent and dispersant are added and continued to be stirred evenly to obtain a spraying slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20% to 50%; the mass ratio of doped M-phase VO2 core-shell particles: floating agent: dispersant is 5:1:1, and finally, the smart radiation coating is obtained by spraying it on the substrate.

[0032] As a preferred embodiment, in the method for preparing the intelligent radiation coating, the components of the compound solvent are ethyl acetate: butyl acetate: xylene = 6:3:4 in terms of mass ratio;

[0033] And / or the resin is acrylic resin, silicone resin, styrene, polyethylene or polystyrene.

[0034] and / or the floating agent is oleic acid;

[0035] And / or the dispersant is Hemmings dispersant 904S.

[0036] Beneficial effects

[0037] (1) Traditional radiant cooling materials can only guarantee a certain cooling effect, but cannot also have a heat preservation function. Therefore, they can only be used in relatively high temperature periods. In low temperature conditions, over-cooling will occur. The intelligent radiant coating provided by the present invention has the functions of cooling, heat preservation, and waterproofing, and can be used in all seasons, making it more practical.

[0038] (2) The intelligent radiation coating proposed in this invention avoids the multilayer film structure commonly used in current VO2 intelligent radiation device materials, which helps reduce the difficulty of optical performance design. In terms of application design, compared with thin film methods, the coating process is simpler and more convenient. In addition, it can be applied to a variety of substrate surfaces such as stainless steel plates, fabrics, and epoxy boards, and has waterproof and heat-insulating functions, and excellent radiant cooling effects.

[0039] (3) The present invention arranges the VO2 core-shell particles uniformly and horizontally on the resin surface. At low temperatures, VO2 is highly permeable, and the high reflectivity of the flaky aluminum powder makes the emissivity of the coating low. At high temperatures (greater than the phase transition temperature), vanadium dioxide is in a metallic phase, forming a metal-medium-metal "sandwich structure". The incident infrared waves will cause a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving the effect of high-temperature cooling. Therefore, the intelligent radiation coating of the present invention radiates energy to the outside when the temperature is high, and hardly radiates energy to the outside when the temperature is low, achieving the purpose of intelligent temperature control and dynamic cooling, and is not affected by the resin type (high infrared absorption characteristics).

[0040] (4) The present invention mainly adopts the atomic layer deposition method to prepare the shell material of VO2 core-shell particles. This method can accurately control the thickness of the shell by controlling the cyclic growth period, thereby greatly optimizing and controlling the infrared modulation performance of the coating, achieving the purpose of increasing the emissivity change value and improving the thermal regulation capability.

[0041] (5) Vanadium dioxide (VO2) undergoes a reversible phase transition from a low-temperature insulating state to a high-temperature metallic state at 68°C. This high phase transition temperature limits its practical application. The present invention dopes VO2 with elements such as tungsten, molybdenum, and boron to lower the phase transition temperature of the smart window device. By controlling the doping levels of different elements, smart radiation coatings with different phase transition temperatures can be obtained to meet the energy-saving control needs of buildings in different regions.

[0042] In summary, the present invention features intelligent dynamic temperature control, a simple structure, ease of large-scale fabrication, and zero energy consumption, making it crucial for addressing over-refrigeration and mitigating the urban heat island effect. Furthermore, it has potential applications in areas such as infrared camouflage. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure and principle of the dual-band smart window.

[0044] Figure 2 It is the modulation performance of VO2 smart radiation coating in the medium-wave infrared atmospheric window.

[0045] Figure 3 It is the modulation performance of VO2 smart radiation coating in the long-wave infrared atmospheric window.

[0046] 1-resin layer, 2-flaky aluminum powder, 3-X material, 4-VO2 shell layer, 5-base layer. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0048] The embodiment provides a smart radiation coating, comprising a base layer 5 and a resin layer 1 above the base layer 5; the upper surface of the resin layer 1 is uniformly dispersed with horizontally oriented flake-shaped doped VO2(M) core-shell particles Al@X@VO2(M);

[0049] The flake-doped VO2(M) core-shell particles Al@X@VO2(M) have a core material of flaky aluminum powder 2 with a reflectivity greater than 90%, an intermediate layer of X material 3 with an infrared transmittance greater than 95%, and a surface layer of doped VO2 shell 4. The X material 3 is calcium fluoride, zinc sulfide, zinc selenide, or barium fluoride.

[0050] Horizontally oriented doped VO2(M) core-shell particles, Al@X@VO2(M), are used to achieve the transition between infrared light reflection and absorption properties.

[0051] Below the phase transition temperature, the permeability of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating; above the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell transforms into M phase, i.e. metallic phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

[0052] In some embodiments, the particle size of the flaky aluminum powder 2 is 5 to 15 μm.

[0053] In some embodiments, the shell thickness of the X material 3 is 300 nm-1000 nm.

[0054] In some embodiments, the VO2 shell layer 4 has a thickness of 20 nm to 60 nm.

[0055] In some embodiments, the VO2 shell layer 4 is doped with tungsten, molybdenum, and boron to lower its phase transition temperature.

[0056] In some embodiments, the base layer 5 is a copper sheet, a flexible tin foil, a textile cloth, a steel plate or an aluminum alloy plate.

[0057] In some embodiments, a method for preparing doped M-phase VO2 core-shell particles is provided, comprising the following steps:

[0058] Step 1: Prepare flaky aluminum powder with a particle size of 5 to 15 μm for later use;

[0059] Step 2: Using atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a thickness of 300 nm to 1000 nm of X material to obtain flaky Al@X core-shell particles;

[0060] Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition:

[0061] (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic layer deposition equipment. Then, raise the chamber temperature to the set value. While filling with argon and maintaining a certain pressure, rotate the chamber to stir the powder and begin growing the coating layer by atomic layer deposition (ALD).

[0062] (3.2) First, a vanadium source and a dopant are introduced and allowed to react for a certain period of time with the –OH groups on the surface of the Al@X core-shell particle substrate. Then, a carrier gas N2 is introduced to remove the methane byproduct generated in this reaction.

[0063] (3.3) Water vapor is then introduced into the cavity to fully react with the –CH3 on the surface. The carrier gas N2 is then introduced again to remove the byproduct CH4. This constitutes one cycle. Al@X@VOx core-shell particles with different shell thicknesses can be obtained by setting different numbers of cycles.

[0064] Step 4: Al@X@VO prepared in step 3 x The particles are calcined in a certain atmosphere to promote VO x The shell transforms to the M phase to obtain doped VO2(M) core-shell particles;

[0065] The atmosphere calcination in step 4 is divided into two stages: the first stage is to keep the temperature at 550°C for 2 hours under 99.99% pure nitrogen;

[0066] The second stage is to keep the temperature at 400-650°C for 10-30 minutes under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

[0067] In some embodiments, the chamber temperature in step (3.1) is set to 150-200°C;

[0068] In some embodiments, the vanadium source in step (3.2) is triisopropoxyvanadium oxide, and the dopant is ammonium molybdate, sodium tungstate, or boric acid.

[0069] In some embodiments, the cycle period in step (3.3) is 400-2000 times.

[0070] In some embodiments, a doped M-phase VO2 core-shell particle is obtained by the preparation method.

[0071] In some embodiments, a method for preparing a smart radiation coating is provided: first, a certain amount of a compound solvent is taken, a resin with a solid content of 50% in the compound solvent is added, and the mixture is stirred evenly in a dispersant; secondly, a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 6 or 7 and a certain amount of a floating agent and a dispersant are added and continued to be stirred evenly to obtain a spraying slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20% to 50%; the mass ratio of the doped M-phase VO2 core-shell particles: floating agent: dispersant is 5:1:1, and finally, the smart radiation coating is obtained by spraying it on the base layer.

[0072] In some embodiments, the preparation method of the smart radiation coating includes: the components of the compounded solvent are, by weight, ethyl acetate: butyl acetate: xylene = 6:3:4; and / or the resin is acrylic resin, silicone resin, styrene, polyethylene, or polystyrene; and / or the floating agent is oleic acid; and / or the dispersant is Hemmings Dispersant 904S.

[0073] like Figure 1 As shown in the figure, the proposed intelligent radiation coating is primarily composed of Al@X@VO2 core-shell particles, a resin binder, and a substrate. First, doped VO2 core-shell particles are obtained through atomic layer deposition and high-temperature calcination. Then, a spray-coated intelligent coating material with high infrared radiation modulation performance is obtained. During use, the VO2 phase transition temperature can be adjusted according to different regions, climates, and time periods to meet the energy-saving requirements of different buildings.

[0074] The performance of the intelligent radiation coating proposed in this invention is analyzed through simulation. Figure 2 and Figure 3The figure shows the coating's modulation performance in the infrared band. The core material is 10μm aluminum flake powder, the middle layer is calcium fluoride, the shell is 500nm thick, the outer layer is VO2, and the thickness is 30nm. The substrate is stainless steel. As can be seen from the figure, the coating's infrared emissivity increases with increasing temperature (the emissivity change is greater than 0.35) in both the mid-wave infrared and far-infrared atmospheric windows. At low temperatures, the window has low radiation properties, thus achieving thermal insulation. As the temperature rises, the emissivity increases, and the window can dissipate heat through radiation, thereby cooling the air and ultimately achieving intelligent temperature control.

[0075] Example 1:

[0076] Preparation of Al@HfO2 core-shell particles:

[0077] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1 Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0078] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0079] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO xThe powder was calcined at 550°C under a nitrogen atmosphere for 1.5 hours, reducing the VO2 shell to V2O3. A constant ratio of oxygen and nitrogen (5% oxygen partial pressure) was then introduced while maintaining the pressure in the vacuum tube furnace at 500°C for 30 minutes to yield the target product, Al@HfO2@VO2(M).

[0080] Preparation of Al@HfO2@VO2 smart radiation coating:

[0081] First, a certain amount of compound solvent (prepared in a mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4) was added to a certain amount of silicone resin (50% solid content). The mixture was stirred and dispersed in a disperser at 1300 r / min for 2 hours. A certain amount of Al@HfO2@VO2(M) was added and stirred and dispersed at 1300 r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed onto a tinplate. The sample was left at room temperature for 4 hours and then baked in a 200°C oven for 2 hours to obtain a coating thickness of 50-60μm.

[0082] Example 2:

[0083] Preparation of Al@HfO2 core-shell particles:

[0084] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1 Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 6000 cycles to obtain Al@HfO2 core-shell particles.

[0085] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0086] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 400 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550°C under a nitrogen atmosphere for 1.5 hours, reducing the VO2 shell to V2O3. A constant ratio of oxygen and nitrogen (5% oxygen partial pressure) was then introduced while maintaining the pressure in the vacuum tube furnace at 500°C for 30 minutes to yield the target product, Al@HfO2@VO2(M).

[0087] Preparation of Al@HfO2@VO2 smart radiation coating:

[0088] First, a certain amount of compound solvent (prepared in a mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4) was added to a certain amount of silicone resin (50% solid content). The mixture was stirred and dispersed in a disperser at 1300 r / min for 2 hours. A certain amount of Al@HfO2@VO2(M) was added and stirred and dispersed at 1300 r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed onto a tinplate. The sample was left at room temperature for 4 hours and then baked in a 200°C oven for 2 hours to obtain a coating thickness of 50-60μm.

[0089] Example 3:

[0090] Preparation of Al@HfO2 core-shell particles:

[0091] Step 1: First, a certain amount of flaky Al powder (10 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formula growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0092] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0093] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((2s-8s-1.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 400 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550°C under a nitrogen atmosphere for 1.5 hours, reducing the VO2 shell to V2O3. A constant ratio of oxygen and nitrogen (5% oxygen partial pressure) was then introduced while maintaining the pressure in the vacuum tube furnace at 500°C for 30 minutes to yield the target product, Al@HfO2@VO2(M).

[0094] Preparation of Al@HfO2@VO2 smart radiation coating:

[0095] First, a certain amount of compound solvent (prepared in a mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4) was added to a certain amount of silicone resin (50% solid content). The mixture was stirred and dispersed in a disperser at 1300 r / min for 2 hours. A certain amount of Al@HfO2@VO2(M) was added and stirred and dispersed at 1300 r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed onto a tinplate. The sample was left at room temperature for 4 hours and then baked in a 200°C oven for 2 hours to obtain a coating thickness of 50-60μm.

[0096] Example 4:

[0097] Preparation of Al@HfO2 core-shell particles:

[0098] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1 Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0099] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0100] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550°C under a nitrogen atmosphere for 1.5 hours, reducing the VO2 shell to V2O3. A constant ratio of oxygen and nitrogen (5% oxygen partial pressure) was then introduced while maintaining the pressure in the vacuum tube furnace at 500°C for 30 minutes to yield the target product, Al@HfO2@VO2(M).

[0101] Preparation of Al@HfO2@VO2 smart radiation coating:

[0102] First, a certain amount of compound solvent (prepared in a mass ratio of ethyl acetate:butyl acetate:xylene = 6:3:4) was added to a certain amount of silicone resin (solid content 50%). The mixture was stirred and dispersed in a disperser at 1300 r / min for 2 hours. A certain amount of Al@HfO2@VO2(M), Hemmings dispersant 904S, and oleic acid were added and stirred and dispersed at 1300 r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed onto a textile fiber cloth. The sample was left at room temperature for 4 hours and then baked in a 200°C oven for 2 hours to obtain a coating with a thickness of 20-30 μm.

[0103] Example 5:

[0104] Preparation of Al@HfO2 core-shell particles:

[0105] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1 Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0106] Doped Al@HfO2@V 1-y Mo y O x (M) Preparation of core-shell particles:

[0107] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature to 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, ammonium molybdate is used as a dopant, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source (dopant)-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@V1-y Mo y O x Core-shell particles. Finally, the dried Al@HfO2@V 1-y Mo y O x The powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere. At this time, the shell VO2 was reduced to V2O3. Then a certain ratio of oxygen and nitrogen (oxygen partial pressure was 5%) was introduced, and the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, Al@HfO2@V 1-y Mo y O2 target product.

[0108] Al@HfO2@V 1-y Mo y Preparation of O2 smart radiation coating:

[0109] First, a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4) was taken, and then a certain amount of silicone resin (solid content 50%) was added. The mixture was stirred and dispersed in a disperser at a speed of 1300 r / min for 2 hours. A certain amount of Al@HfO2@V was added. 1-y Mo y O2, Hemmings dispersant 904S, and oleic acid were stirred and dispersed at 1300 r / min for 5 minutes to produce a coating. The prepared coating was then sprayed onto a textile fiber cloth. The sample was left at room temperature for 4 hours and then baked in an oven at 200°C for 2 hours to obtain a coating with a thickness of 20-30 μm.

[0110] Example 6:

[0111] Preparation of Al@HfO2 core-shell particles:

[0112] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 ° C and maintained for 1 hour to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 ° C, and argon was filled and the pressure was maintained at 17.3 Pa (1.3×10 -1 Torr) conditions, the powder was stirred in a rotating chamber and the coating layer was grown using ALD. Next, tetrakis(ethylmethylamino hafnium), H2O, and Ar were used as the Hf precursor, oxidant, and purge gas, respectively. The feed and purge times of the Hf precursor were fixed at 1.5s and 30s, respectively, while the feed and purge times of the oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was repeated for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0113] Doped Al@HfO2@V 1-y W y Preparation of O2(M) core-shell particles:

[0114] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature to 200°C, fill it with argon and maintain the pressure at 2.5 torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, ammonium tungstate is used as a dopant, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source (dopant)-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@V 1-y W y O x Core-shell particles. Finally, the dried Al@HfO2@V 1-y W y O x The powder was calcined at 600℃ in a nitrogen atmosphere for 1.5 hours. At this time, the shell VO2 was reduced to V2O3. Then a certain ratio of oxygen and nitrogen (oxygen partial pressure of 10%) was introduced, while the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30 minutes, Al@HfO2@V 1-y W y O2 target product.

[0115] Al@HfO2@V 1-y W y Preparation of O2 smart radiation coating:

[0116] First, a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4) was taken, and then a certain amount of silicone resin (solid content 50%) was added. The mixture was stirred and dispersed in a disperser at a speed of 1300 r / min for 2 hours. A certain amount of Al@HfO2@V was added. 1-y W y O2, Hemmings dispersant 904S, and oleic acid were stirred and dispersed at 1300 r / min for 5 minutes to produce a coating. The prepared coating was then sprayed onto a textile fiber cloth. The sample was left at room temperature for 4 hours and then baked in a 200°C oven for 2 hours to obtain a coating with a thickness of 30-40 μm.

[0117] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A smart radiation coating, characterized in that: It comprises a base layer (5) and a resin layer (1) above the base layer (5); the upper surface of the resin layer (1) is uniformly dispersed with horizontally oriented flaky doped VO2(M) core-shell particles Al@X@VO2(M); The flake-doped VO2(M) core-shell particles Al@X@VO2(M) have a core material of flake aluminum powder (2) with a reflectivity greater than 90%, an intermediate layer of X material (3) with an infrared transmittance greater than 95%, and a surface layer of a doped VO2 shell (4), wherein the X material (3) is calcium fluoride, zinc sulfide, zinc selenide or barium fluoride, and the thickness of the VO2 shell (4) is 20nm-60nm; Horizontally oriented doped VO2(M) core-shell particles, Al@X@VO2(M), are used to achieve the transition between infrared light reflection and absorption properties. Below the phase transition temperature, the permeability of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating; above the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell transforms into the M phase, i.e. the metallic phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

2. The smart radiation coating according to claim 1, characterized in that: The particle size of the flaky aluminum powder (2) is 5-15 μm; And / or the shell thickness of the X material (3) is 300nm-1000nm.

3. The smart radiation coating according to claim 1, characterized in that: The VO2 shell layer (4) is doped with tungsten, molybdenum and boron elements to reduce its phase transition temperature.

4. The smart radiation coating according to claim 1, characterized in that: The base layer (5) is a copper sheet, a flexible tin foil, a textile cloth, a steel plate or an aluminum alloy plate.

5. A method for preparing doped M-phase VO2 core-shell particles, characterized in that The following steps are involved: Step 1: Prepare flaky aluminum powder with a particle size of 5-15 μm for later use; Step 2: Using atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a 300 nm to 1000 nm thick X material to obtain flaky Al@X core-shell particles; the X material is calcium fluoride, zinc sulfide, zinc selenide, or barium fluoride; Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition: (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic layer deposition equipment. Then, raise the chamber temperature to the set value. While filling with argon and maintaining a certain pressure, rotate the chamber to stir the powder and begin growing the coating layer using atomic layer deposition (ALD). (3.2) First, a vanadium source and dopant are introduced and allowed to react for a certain period of time with the –OH groups on the surface of the Al@X core-shell particle substrate. Then, a carrier gas, N2, is introduced to remove the methane byproduct generated in this reaction. (3.3) Water vapor is then introduced into the cavity to fully react with the –CH3 on the surface. The carrier gas N2 is then introduced again to remove the byproduct CH4. This constitutes one cycle, and Al@X@VOx core-shell particles with different shell thicknesses can be obtained by setting different numbers of cycles. Step 4: Al@X@VO prepared in step 3 x The particles are calcined in a certain atmosphere to promote VO x The shell transforms to the M phase to obtain doped VO2(M) core-shell particles; The atmosphere calcination in step 4 is divided into two stages: the first stage is to keep the temperature at 550°C for 2 hours under 99.99% pure nitrogen; The second stage is to keep the temperature at 400-650°C for 10-30 minutes under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

6. The method for preparing doped M-phase VO2 core-shell particles according to claim 5, characterized in that: The chamber temperature in step (3.1) is set to 150-200°C; And / or in step (3.2), the vanadium source is triisopropoxyvanadium oxide, and the dopant is ammonium molybdate, sodium tungstate or boric acid; And / or the cycle period in step (3.3) is 400-2000 times.

7. A doped M-phase VO2 core-shell particle, characterized in that The method is obtained by the preparation method according to claim 5 or 6.

8. A method for preparing an intelligent radiation coating, characterized in that: First, a certain amount of compound solvent is taken, and a resin with a solid content of 50% in the compound solvent is added and stirred evenly in a dispersant; secondly, a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 5 or 6 and a certain amount of floating agent and dispersant are added and continued to be stirred evenly to obtain a spraying slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20%~50%; the mass ratio of doped M-phase VO2 core-shell particles: floating agent: dispersant is =5:1:1, and finally, the smart radiation coating is obtained by spraying it on the substrate.

9. The method for preparing the smart radiation coating according to claim 8, characterized in that: The components of the composite solvent are ethyl acetate: butyl acetate: xylene = 6:3:4 in terms of mass ratio; and / or the resin is acrylic resin, silicone resin, styrene, polyethylene or polystyrene; and / or the floating agent is oleic acid; And / or the dispersant is Hemmings dispersant 904S.

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